Scientific Articles, Reports & Theses
List of Publications
Select tag “Algoryx” for publications affiliated with Algoryx, or “External” for external publications that use or cite Algoryx software.
2022 |
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![]() | Yang, Yuxuan; Stork, Johannes A; Stoyanov, Todor: Online Model Learning for Shape Control of Deformable Linear Objects. 2022 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), pp. 4056-4062, 2022. (Type: Journal Article | Abstract | Links | BibTeX | Tags: External) @article{yang2022, title = {Online Model Learning for Shape Control of Deformable Linear Objects}, author = {Yuxuan Yang and Johannes A. Stork and Todor Stoyanov}, url = {https://ieeexplore.ieee.org/document/9981080}, doi = {10.1109/IROS47612.2022.9981080}, year = {2022}, date = {2022-12-26}, journal = {2022 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)}, pages = {4056-4062}, abstract = {Traditional approaches to manipulating the state of deformable linear objects (DLOs) - i.e., cables, ropes - rely on model-based planning. However, constructing an accurate dynamic model of a DLO is challenging due to the complexity of interactions and a high number of degrees of freedom. This renders the task of achieving a desired DLO shape particularly difficult and motivates the use of model-free alternatives, which while maintaining generality suffer from a high sample complexity. In this paper, we bridge the gap between these fundamentally different approaches and propose a framework that learns dynamic models of DLOs through trial-and-error interaction. Akin to model-based reinforcement learning (RL), we interleave learning and exploration to solve a 3D shape control task for a DLO. Our approach requires only a fraction of the interaction samples of the current state-of-the-art model-free RL alternatives to achieve superior shape control performance. Unlike offline model learning, our approach does not require expert knowledge for data collection, retains the ability to explore, and automatically selects relevant experience.}, keywords = {External}, pubstate = {published}, tppubtype = {article} } Traditional approaches to manipulating the state of deformable linear objects (DLOs) - i.e., cables, ropes - rely on model-based planning. However, constructing an accurate dynamic model of a DLO is challenging due to the complexity of interactions and a high number of degrees of freedom. This renders the task of achieving a desired DLO shape particularly difficult and motivates the use of model-free alternatives, which while maintaining generality suffer from a high sample complexity. In this paper, we bridge the gap between these fundamentally different approaches and propose a framework that learns dynamic models of DLOs through trial-and-error interaction. Akin to model-based reinforcement learning (RL), we interleave learning and exploration to solve a 3D shape control task for a DLO. Our approach requires only a fraction of the interaction samples of the current state-of-the-art model-free RL alternatives to achieve superior shape control performance. Unlike offline model learning, our approach does not require expert knowledge for data collection, retains the ability to explore, and automatically selects relevant experience. |
![]() | Styrud, Jonathan ; Iovino, Matteo ; Norrlöf, Mikael ; Björkman, Mårten ; Smith, Christian : Combining planning and learning of behavior trees for robotic assembly. 2022 International Conference on Robotics and Automation (ICRA), pp. 11511–11517, IEEE, 2022. (Type: Inproceedings | Abstract | Links | BibTeX | Tags: External) @inproceedings{styrud2022combining, title = {Combining planning and learning of behavior trees for robotic assembly}, author = {Styrud, Jonathan and Iovino, Matteo and Norrlöf, Mikael and Björkman, Mårten and Smith, Christian}, url = {https://ieeexplore.ieee.org/abstract/document/9812086 https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=9812086}, doi = {10.1109/ICRA46639.2022.9812086}, year = {2022}, date = {2022-10-01}, booktitle = {2022 International Conference on Robotics and Automation (ICRA)}, pages = {11511--11517}, publisher = {IEEE}, abstract = {Industrial robots can solve tasks in controlled environments, but modern applications require robots able to operate also in unpredictable surroundings. An increasingly popular reactive policy architecture in robotics is Behavior Trees (BTs) but as other architectures, programming time drives cost and limits flexibility. The two main branches of algorithms to generate policies automatically, automated planning and machine learning, both have their own drawbacks and have not previously been combined for generation of BTs. We propose a method for creating BTs by combining these branches, inserting the result of an automated planner into the population of a Genetic Programming algorithm. Experiments confirm that the proposed method performs well on a variety of robotic assembly problems and outperforms the base methods used separately. We also show that this high level learning of Behavior Trees can be transferred to a real system without further training.}, keywords = {External}, pubstate = {published}, tppubtype = {inproceedings} } Industrial robots can solve tasks in controlled environments, but modern applications require robots able to operate also in unpredictable surroundings. An increasingly popular reactive policy architecture in robotics is Behavior Trees (BTs) but as other architectures, programming time drives cost and limits flexibility. The two main branches of algorithms to generate policies automatically, automated planning and machine learning, both have their own drawbacks and have not previously been combined for generation of BTs. We propose a method for creating BTs by combining these branches, inserting the result of an automated planner into the population of a Genetic Programming algorithm. Experiments confirm that the proposed method performs well on a variety of robotic assembly problems and outperforms the base methods used separately. We also show that this high level learning of Behavior Trees can be transferred to a real system without further training. |
![]() | Cosgun, A; van Steen,: Impact-aware dual-arm grasping through time-invariant reference spreading. 2022. (Type: Journal Article | Abstract | Links | BibTeX | Tags: External) @article{cosgunimpact, title = {Impact-aware dual-arm grasping through time-invariant reference spreading}, author = {Cosgun, A and van Steen}, url = {https://pure.tue.nl/ws/portalfiles/portal/224201404/1020574_Impact_aware_grasping_through_time_invariant_reference_spreading.pdf}, year = {2022}, date = {2022-10-01}, abstract = {Eindhoven University of Technology}, abstract = {In robotic applications which involve handling objects or interaction with the environment, robots generally establish contact at near-zero speed due to the effect of impacts. At impact, rapid velocity changes occur in the robot joints accompanied by large contact forces, which can cause damage to the robot, humans, or the environment. As a result, robots typically accelerate and decelerate repeatedly to achieve a task that involves contact, which negatively affects the energy consumption and throughput. In order to increase the performance, control strategies are proposed that take into account the impact dynamics, which are referred to as impact-aware control. Impact-aware control strategies exploit impacts, to increase the swiftness of the performed tasks and reach a more human-like behavior. One of the challenges in impact-aware control strategies is that, in presence of uncertainties, a robot can experience an impact at a different time than expected. This causes the actual state of the system to reside in a different mode than prescribed by the time-based reference trajectory, which can cause the robot to compensate aggressively and possibly becoming unstable. Furthermore, when contact is expected to be established at multiple contact points simultaneously, the controller can enter an unspecified and typically unpredictable mode. Lastly, in case of external perturbations, the robot can lag behind compared to its reference state at that time instant, which would cause the robot to “catch up” in order to reach its desired state, which would generally be undesired. The combination of a time-invariant control strategies and an impact-aware reference spreading control strategy can provide a possible solution for these challenges. By employing a reference that is solely a function of the robot’s position and orientation, and extending it around an expected impact position, robots can be controlled towards an intentional impact in the presence of uncertainties. Therefore, the goal of this project is to design an impact-aware time-invariant reference spreading control strategy for a dual-arm robotic system capable of swift grasping. To achieve this, a procedure is proposed to generate time-invariant references that can steer the robots towards a desired position and speed to swiftly grasp an object, while ensuring the reference is compatible through the impact dynamics. In order to be applicable on a dual-arm robotic system, the time-invariant reference spreading control strategy is cast into a task-based quadratic-programming control framework, which is a common framework for control of complex systems. Furthermore, an intermediate mode control strategy is proposed to ensure full contact is established when a loss of simultaneity occurs. Additionally, a synchronization strategy is formulated to ensure the robots reach the object at the same time. Finally, the effectiveness of the proposed control approach is validated by means of numerical simulation studies on a two-dimensional, and a more complex three-dimensional scenario, which consists of a realistic seven degrees of freedom robot setup.}, keywords = {External}, pubstate = {published}, tppubtype = {article} } Eindhoven University of Technology}, abstract = {In robotic applications which involve handling objects or interaction with the environment, robots generally establish contact at near-zero speed due to the effect of impacts. At impact, rapid velocity changes occur in the robot joints accompanied by large contact forces, which can cause damage to the robot, humans, or the environment. As a result, robots typically accelerate and decelerate repeatedly to achieve a task that involves contact, which negatively affects the energy consumption and throughput. In order to increase the performance, control strategies are proposed that take into account the impact dynamics, which are referred to as impact-aware control. Impact-aware control strategies exploit impacts, to increase the swiftness of the performed tasks and reach a more human-like behavior. One of the challenges in impact-aware control strategies is that, in presence of uncertainties, a robot can experience an impact at a different time than expected. This causes the actual state of the system to reside in a different mode than prescribed by the time-based reference trajectory, which can cause the robot to compensate aggressively and possibly becoming unstable. Furthermore, when contact is expected to be established at multiple contact points simultaneously, the controller can enter an unspecified and typically unpredictable mode. Lastly, in case of external perturbations, the robot can lag behind compared to its reference state at that time instant, which would cause the robot to “catch up” in order to reach its desired state, which would generally be undesired. The combination of a time-invariant control strategies and an impact-aware reference spreading control strategy can provide a possible solution for these challenges. By employing a reference that is solely a function of the robot’s position and orientation, and extending it around an expected impact position, robots can be controlled towards an intentional impact in the presence of uncertainties. Therefore, the goal of this project is to design an impact-aware time-invariant reference spreading control strategy for a dual-arm robotic system capable of swift grasping. To achieve this, a procedure is proposed to generate time-invariant references that can steer the robots towards a desired position and speed to swiftly grasp an object, while ensuring the reference is compatible through the impact dynamics. In order to be applicable on a dual-arm robotic system, the time-invariant reference spreading control strategy is cast into a task-based quadratic-programming control framework, which is a common framework for control of complex systems. Furthermore, an intermediate mode control strategy is proposed to ensure full contact is established when a loss of simultaneity occurs. Additionally, a synchronization strategy is formulated to ensure the robots reach the object at the same time. Finally, the effectiveness of the proposed control approach is validated by means of numerical simulation studies on a two-dimensional, and a more complex three-dimensional scenario, which consists of a realistic seven degrees of freedom robot setup. |
![]() | van Oorschot, S P M: Design and numerical validation of a dual-arm telerobotic simulation for object grabbing. Eindhoven University of Technology, 2022. (Type: Masters Thesis | Abstract | Links | BibTeX | Tags: External) @mastersthesis{Oorschot2022, title = {Design and numerical validation of a dual-arm telerobotic simulation for object grabbing}, author = {van Oorschot, S.P.M.}, url = {https://pure.tue.nl/ws/portalfiles/portal/211664977/1014209_Oorschot.pdf}, year = {2022}, date = {2022-10-01}, school = {Eindhoven University of Technology}, abstract = {Currently, most robots in the parcel industry manipulate objects by making contact with a near-zero velocity, limiting their movement to pick-and-place actions. The incorporation of impacts, i.e., making contact with non-zero velocity, in the control of robots can extend the robot’s actions with grabbing, which improves the throughput of such systems. The control of robots during impact requires the use of novel control algorithms, for which an estimation of the robot’s impact behavior is required. The application and development of such control algorithms, and the study towards robot impacts in order to improve such estimations are both subjected to the impulsive nature of impacts, and the complications that arise consequentially. First of all, impacting with robots poses a safety hazard for both the operator, the robot, and the environment, as impacts are often paired with quick changes in velocity, peaking forces, and peaking torques. Second of all, the generation of reference trajectories for robotic grabbing is time-consuming and undextrous, which raises the need for a more human-oriented method of instructing robot reference trajectories. In this work, a software framework is developed which aims at tackling both of the aforementioned problems. This framework combines the human capability of trajectory planning and of performing swift grabbing actions by controlling the robot setup via teleoperation. The teleoperated reference trajectories control a QP controller, which interacts with a simulation of the robot scene which mimics real life physics, allowing preliminary testing to be conducted on this virtual system. Experiments are conducted to test the usability of the teleoperation system. Furthermore, to illustrate that the system can indeed aid in development of novel control techniques and impact behavior estimations, experiments are conducted which focus on the effect of the robot posture and the end effector impact location on the impact behavior of the system. Results show that the developed system is intuitive to use, and that the robot elbow pose and the location of the impact have a significant effect on the robot’s impact behavior.}, keywords = {External}, pubstate = {published}, tppubtype = {mastersthesis} } Currently, most robots in the parcel industry manipulate objects by making contact with a near-zero velocity, limiting their movement to pick-and-place actions. The incorporation of impacts, i.e., making contact with non-zero velocity, in the control of robots can extend the robot’s actions with grabbing, which improves the throughput of such systems. The control of robots during impact requires the use of novel control algorithms, for which an estimation of the robot’s impact behavior is required. The application and development of such control algorithms, and the study towards robot impacts in order to improve such estimations are both subjected to the impulsive nature of impacts, and the complications that arise consequentially. First of all, impacting with robots poses a safety hazard for both the operator, the robot, and the environment, as impacts are often paired with quick changes in velocity, peaking forces, and peaking torques. Second of all, the generation of reference trajectories for robotic grabbing is time-consuming and undextrous, which raises the need for a more human-oriented method of instructing robot reference trajectories. In this work, a software framework is developed which aims at tackling both of the aforementioned problems. This framework combines the human capability of trajectory planning and of performing swift grabbing actions by controlling the robot setup via teleoperation. The teleoperated reference trajectories control a QP controller, which interacts with a simulation of the robot scene which mimics real life physics, allowing preliminary testing to be conducted on this virtual system. Experiments are conducted to test the usability of the teleoperation system. Furthermore, to illustrate that the system can indeed aid in development of novel control techniques and impact behavior estimations, experiments are conducted which focus on the effect of the robot posture and the end effector impact location on the impact behavior of the system. Results show that the developed system is intuitive to use, and that the robot elbow pose and the location of the impact have a significant effect on the robot’s impact behavior. |
![]() | Aoshima, Koji ; Lindmark, Daniel ; Servin, Martin : Examining the simulation-to-reality-gap of a wheel loader interacting with deformable terrain. 11th Asia-Pacific Regional Conference of the ISTVS September 26-28, 2022, Harbin, China, 2022. (Type: Conference | Abstract | Links | BibTeX | Tags: External) @conference{aoshima2022examining, title = {Examining the simulation-to-reality-gap of a wheel loader interacting with deformable terrain}, author = {Aoshima, Koji and Lindmark, Daniel and Servin, Martin}, url = {http://umit.cs.umu.se/wl-sim2real/}, year = {2022}, date = {2022-09-01}, booktitle = {11th Asia-Pacific Regional Conference of the ISTVS September 26-28, 2022, Harbin, China}, abstract = {Simulators are essential for developing autonomous control of off-road vehicles and heavy equipment. They allow automatic testing under safe and controllable conditions, and the generation of large amounts of synthetic and annotated training data necessary for deep learning to be applied [1]. Limiting factors are the computational speed and how accurately the simulator reflects the real system. When the deviation is too large, a controller transfers poorly from the simulated to the real environment. On the other hand, a finely resolved simulator easily becomes too computationally intense and slow for running the necessary number of simulations or keeping realtime pace with hardware in the loop. We investigate how well a physics-based simulator can be made to match its physical counterpart, a full-scale wheel loader instrumented with motion and force sensors performing a bucket filling operation [2]. The simulated vehicle is represented as a rigid multibody system with nonsmooth contact and driveline dynamics. The terrain model combines descriptions of the frictional-cohesive soil as a continuous solid and particles, discretized in voxels and discrete elements [3]. Strong and stable force coupling with the equipment is mediated via rigid aggregate bodies capturing the bulk mechanics of the soil. The results include analysis of the agreement between a calibrated simulation model and the field tests, and of how the simulation performance and accuracy depend on spatial and temporal resolution. The system’s degrees of freedom range from hundreds to millions and the simulation speed up to ten times faster than realtime. Furthermore, it is investigated how sensitive a deep learning controller is to variations in the simulator environment parameters.}, keywords = {External}, pubstate = {published}, tppubtype = {conference} } Simulators are essential for developing autonomous control of off-road vehicles and heavy equipment. They allow automatic testing under safe and controllable conditions, and the generation of large amounts of synthetic and annotated training data necessary for deep learning to be applied [1]. Limiting factors are the computational speed and how accurately the simulator reflects the real system. When the deviation is too large, a controller transfers poorly from the simulated to the real environment. On the other hand, a finely resolved simulator easily becomes too computationally intense and slow for running the necessary number of simulations or keeping realtime pace with hardware in the loop. We investigate how well a physics-based simulator can be made to match its physical counterpart, a full-scale wheel loader instrumented with motion and force sensors performing a bucket filling operation [2]. The simulated vehicle is represented as a rigid multibody system with nonsmooth contact and driveline dynamics. The terrain model combines descriptions of the frictional-cohesive soil as a continuous solid and particles, discretized in voxels and discrete elements [3]. Strong and stable force coupling with the equipment is mediated via rigid aggregate bodies capturing the bulk mechanics of the soil. The results include analysis of the agreement between a calibrated simulation model and the field tests, and of how the simulation performance and accuracy depend on spatial and temporal resolution. The system’s degrees of freedom range from hundreds to millions and the simulation speed up to ten times faster than realtime. Furthermore, it is investigated how sensitive a deep learning controller is to variations in the simulator environment parameters. |
![]() | Fälldin, Arvid: Learning by Digging: A Differentiable Prediction Model for an Autonomous Wheel Loader. Department of Physics, Umeå University, 2022. (Type: Masters Thesis | Abstract | Links | BibTeX | Tags: External) @mastersthesis{Falldin2022, title = {Learning by Digging: A Differentiable Prediction Model for an Autonomous Wheel Loader}, author = {Arvid Fälldin}, url = {http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-197165 http://www.diva-portal.org/smash/get/diva2:1675538/FULLTEXT01.pdf}, year = {2022}, date = {2022-06-22}, school = {Department of Physics, Umeå University}, abstract = {Wheel loaders are heavy duty machines that are ubiquitous on construction sites and in mines all over the world. Fully autonomous wheel loaders remains an open problem but the industry is hoping that increasing their level of autonomy will help to reduce costs and energy consumption while also increasing workplace safety. Operating a wheel loader efficiently requires dig plans that extend over multiple dig cycles and not just one at a time. This calls for a model that can predict both the performance of a dig action and the resulting shape of the pile. In this thesis project, we use simulations to develop a data-driven artificial neural network model that can predict the outcome of a dig action. The model is able to predict the wheel loader’s productivity with an average error of 7.3%, and the altered shape of the pile with an average relative error of 4.5%. We also show that automatic differentiation techniques can be used to accurately differentiate the model with respect to input. This makes it possible to use gradient-based optimization methods to find the dig action that maximises the performance of the wheel loader.}, keywords = {External}, pubstate = {published}, tppubtype = {mastersthesis} } Wheel loaders are heavy duty machines that are ubiquitous on construction sites and in mines all over the world. Fully autonomous wheel loaders remains an open problem but the industry is hoping that increasing their level of autonomy will help to reduce costs and energy consumption while also increasing workplace safety. Operating a wheel loader efficiently requires dig plans that extend over multiple dig cycles and not just one at a time. This calls for a model that can predict both the performance of a dig action and the resulting shape of the pile. In this thesis project, we use simulations to develop a data-driven artificial neural network model that can predict the outcome of a dig action. The model is able to predict the wheel loader’s productivity with an average error of 7.3%, and the altered shape of the pile with an average relative error of 4.5%. We also show that automatic differentiation techniques can be used to accurately differentiate the model with respect to input. This makes it possible to use gradient-based optimization methods to find the dig action that maximises the performance of the wheel loader. |
![]() | Özdemir, Erdougan ; Coramik, Mustafa : Development of a virtual teaching environment with Algodoo:‘eye’and ‘cactus type light source’models. Physics Education, 57 (4), pp. 045022, 2022. (Type: Journal Article | Links | BibTeX | Tags: External) @article{ozdemir2022development, title = {Development of a virtual teaching environment with Algodoo:‘eye’and ‘cactus type light source’models}, author = {Özdemir, Erdougan and Coramik, Mustafa}, url = {https://iopscience.iop.org/article/10.1088/1361-6552/ac60b0/pdf}, year = {2022}, date = {2022-05-01}, journal = {Physics Education}, volume = {57}, number = {4}, pages = {045022}, keywords = {External}, pubstate = {published}, tppubtype = {article} } |
![]() | Cao, Muqing ; Cao, Kun ; Yuan, Shenghai ; Nguyen, Thien-Minh ; Xie, Lihua : NEPTUNE: Non-Entangling Planning for Multiple Tethered Unmanned Vehicles. arxiv:2212.01536, 2022. (Type: Journal Article | Links | BibTeX | Tags: External) @article{Cao2022, title = {NEPTUNE: Non-Entangling Planning for Multiple Tethered Unmanned Vehicles}, author = {Cao, Muqing and Cao, Kun and Yuan, Shenghai and Nguyen, Thien-Minh and Xie, Lihua}, url = {https://arxiv.org/abs/2212.01536 https://arxiv.org/pdf/2212.01536}, year = {2022}, date = {2022-04-01}, journal = {arxiv:2212.01536}, keywords = {External}, pubstate = {published}, tppubtype = {article} } |
![]() | Wallin, E; Wiberg, V; Vesterlund, F; Holmgren, J; Persson, H; Servin, M: Learning multiobjective rough terrain traversability. Journal of Terramechanics, 102 , pp. 17-26, 2022. (Type: Journal Article | Abstract | Links | BibTeX | Tags: External) @article{wallin2022, title = {Learning multiobjective rough terrain traversability}, author = {Wallin, E. and Wiberg, V. and Vesterlund, F. and Holmgren, J. and Persson, H. and Servin, M.}, url = {https://authors.elsevier.com/sd/article/S0022489822000313 https://www.sciencedirect.com/science/article/pii/S0022489822000313/pdfft?md5=5dda8fdd1e395ea0e205c16deda5aed4&pid=1-s2.0-S0022489822000313-main.pdf https://arxiv.org/pdf/2203.16354.pdf}, doi = {10.1016/j.jterra.2022.04.002 }, year = {2022}, date = {2022-04-01}, journal = {Journal of Terramechanics}, volume = {102}, pages = {17-26}, abstract = {We present a method that uses high-resolution topography data of rough terrain and ground vehicle simulation to predict traversability. Traversability is expressed as three independent measures: the ability to traverse the terrain at a target speed, energy consumption, and acceleration. The measures are continuous and reflect different objectives for planning that go beyond binary classification. A deep neural network is trained to predict the traversability measures from the local heightmap and target speed. To produce training data, we use an articulated vehicle with wheeled bogie suspensions and procedurally generated terrains. We evaluate the model on laser-scanned forest terrains, previously unseen by the model. The model predicts traversability with an accuracy of 90%. Predictions rely on features from the high-dimensional terrain data that surpass local roughness and slope relative to the heading. Correlations show that the three traversability measures are complementary to each other. With an inference speed 3000 times faster than the ground truth simulation and trivially parallelizable, the model is well suited for traversability analysis and optimal route planning over large areas.}, keywords = {External}, pubstate = {published}, tppubtype = {article} } We present a method that uses high-resolution topography data of rough terrain and ground vehicle simulation to predict traversability. Traversability is expressed as three independent measures: the ability to traverse the terrain at a target speed, energy consumption, and acceleration. The measures are continuous and reflect different objectives for planning that go beyond binary classification. A deep neural network is trained to predict the traversability measures from the local heightmap and target speed. To produce training data, we use an articulated vehicle with wheeled bogie suspensions and procedurally generated terrains. We evaluate the model on laser-scanned forest terrains, previously unseen by the model. The model predicts traversability with an accuracy of 90%. Predictions rely on features from the high-dimensional terrain data that surpass local roughness and slope relative to the heading. Correlations show that the three traversability measures are complementary to each other. With an inference speed 3000 times faster than the ground truth simulation and trivially parallelizable, the model is well suited for traversability analysis and optimal route planning over large areas. |
![]() | Shintani, T; Saito, Y; Kiritani, Y; Ozawa, S; Obayashi, K: Applying Model-based Development to Performance Development of Hydraulic Excavators Using 1DCAE. Komatsu Technical Report (Vol.67 No.174), 2022. (Type: Technical Report | Abstract | Links | BibTeX | Tags: External) @techreport{Shintani2022, title = {Applying Model-based Development to Performance Development of Hydraulic Excavators Using 1DCAE}, author = {Shintani, T. and Saito, Y. and Kiritani, Y. and Ozawa, S. and Obayashi, K.}, url = {https://www.komatsu.jp/en/-/media/home/aboutus/innovation/technology/techreport/2021/en/174e01.pdf}, year = {2022}, date = {2022-03-31}, number = {Vol.67 No.174}, institution = {Komatsu Technical Report}, abstract = {The requirements for construction machinery are becoming more sophisticated year by year, and the systems are becoming larger and more complex. Komatsu is aiming for efficient development even in large and complicated systems by applying model-based development to vehicle performance development. This paper reports an application example of using 1DCAE for the performance development of a hydraulic excavator, and also introduces examples of further utilization of 1DCAE such as a simulator.}, keywords = {External}, pubstate = {published}, tppubtype = {techreport} } The requirements for construction machinery are becoming more sophisticated year by year, and the systems are becoming larger and more complex. Komatsu is aiming for efficient development even in large and complicated systems by applying model-based development to vehicle performance development. This paper reports an application example of using 1DCAE for the performance development of a hydraulic excavator, and also introduces examples of further utilization of 1DCAE such as a simulator. |
![]() | Song, Ruitao ; Ye, Zhixian ; Wang, Liyang ; He, Tianyi ; Zhang, Liangjun : Autonomous Wheel Loader Trajectory Tracking Control Using LPV-MPC. arxiv:2203.08944, 2022. (Type: Journal Article | Abstract | Links | BibTeX | Tags: External) @article{Song2022, title = {Autonomous Wheel Loader Trajectory Tracking Control Using LPV-MPC}, author = {Song, Ruitao and Ye, Zhixian and Wang, Liyang and He, Tianyi and Zhang, Liangjun}, url = {https://arxiv.org/abs/2203.08944 https://youtu.be/QbNfS_wZKKA}, doi = {https://doi.org/10.48550/arxiv.2203.08944}, year = {2022}, date = {2022-03-30}, journal = {arxiv:2203.08944}, abstract = {In this paper, we present a systematic approach for high-performance and efficient trajectory tracking control of autonomous wheel loaders. With the nonlinear dynamic model of a wheel loader, nonlinear model predictive control (MPC) is used in offline trajectory planning to obtain a high-performance state-control trajectory while satisfying the state and control constraints. In tracking control, the nonlinear model is embedded into a Linear Parameter Varying (LPV) model and the LPV-MPC strategy is used to achieve fast online computation and good tracking performance. To demonstrate the effectiveness and the advantages of the LPV-MPC, we test and compare three model predictive control strategies in the high-fidelity simulation environment. With the planned trajectory, three tracking control strategies LPV-MPC, nonlinear MPC, and LTI-MPC are simulated and compared in the perspectives of computational burden and tracking performance. The LPV-MPC can achieve better performance than conventional LTI-MPC because more accurate nominal system dynamics are captured in the LPV model. In addition, LPV-MPC achieves slightly worse tracking performance but tremendously improved computational efficiency than nonlinear MPC. A video with loading cycles completed by our autonomous wheel loader in the simulation environment can be found here: this https URL.}, keywords = {External}, pubstate = {published}, tppubtype = {article} } In this paper, we present a systematic approach for high-performance and efficient trajectory tracking control of autonomous wheel loaders. With the nonlinear dynamic model of a wheel loader, nonlinear model predictive control (MPC) is used in offline trajectory planning to obtain a high-performance state-control trajectory while satisfying the state and control constraints. In tracking control, the nonlinear model is embedded into a Linear Parameter Varying (LPV) model and the LPV-MPC strategy is used to achieve fast online computation and good tracking performance. To demonstrate the effectiveness and the advantages of the LPV-MPC, we test and compare three model predictive control strategies in the high-fidelity simulation environment. With the planned trajectory, three tracking control strategies LPV-MPC, nonlinear MPC, and LTI-MPC are simulated and compared in the perspectives of computational burden and tracking performance. The LPV-MPC can achieve better performance than conventional LTI-MPC because more accurate nominal system dynamics are captured in the LPV model. In addition, LPV-MPC achieves slightly worse tracking performance but tremendously improved computational efficiency than nonlinear MPC. A video with loading cycles completed by our autonomous wheel loader in the simulation environment can be found here: this https URL. |
![]() | Ürek, Handan; Çoramik, Mustafa: A Suggestion and Evaluation of a STEM Activity about Friction Coefficient for Pre-Service Science Teachers. Journal of Computer and Education Research, 10 (19), pp. 202 - 235, 2022. (Type: Journal Article | Abstract | Links | BibTeX | Tags: External) @article{Urek2022, title = {A Suggestion and Evaluation of a STEM Activity about Friction Coefficient for Pre-Service Science Teachers}, author = {Handan Ürek and Mustafa Çoramik}, url = {https://dergipark.org.tr/en/pub/jcer/issue/69325/1063301 https://dergipark.org.tr/en/download/article-file/2214073}, doi = {10.18009/jcer.1063301}, year = {2022}, date = {2022-01-02}, journal = {Journal of Computer and Education Research}, volume = {10}, number = {19}, pages = {202 - 235}, abstract = {In this study, the process of developing and evaluating a STEM activity which can be implemented during Science Teaching Laboratory Practice course in accordance with the 5E Model related to the concept of friction coefficient was addressed. The implementation of the activity was conducted in the form of a case study with the participation of 16 third year pre-service science teachers. Student journal forms and worksheets were utilized for the evaluation of the activity. As a result, it was determined that planned activity could be successfully applied to the pre-service teachers during the weekly course hours of Science Teaching Laboratory Practice course. In addition, positive feedbacks were obtained from pre-service teachers’ evaluation for the activity. It is believed that such studies, which establish connections between science and different disciplines, can contribute to the training of qualified science teachers and that such studies should be given more space in science teacher education. }, keywords = {External}, pubstate = {published}, tppubtype = {article} } In this study, the process of developing and evaluating a STEM activity which can be implemented during Science Teaching Laboratory Practice course in accordance with the 5E Model related to the concept of friction coefficient was addressed. The implementation of the activity was conducted in the form of a case study with the participation of 16 third year pre-service science teachers. Student journal forms and worksheets were utilized for the evaluation of the activity. As a result, it was determined that planned activity could be successfully applied to the pre-service teachers during the weekly course hours of Science Teaching Laboratory Practice course. In addition, positive feedbacks were obtained from pre-service teachers’ evaluation for the activity. It is believed that such studies, which establish connections between science and different disciplines, can contribute to the training of qualified science teachers and that such studies should be given more space in science teacher education. |
![]() | Mustafa, Erdoğan Özdemir
Coramik: Development of a virtual teaching environment with Algodoo: eye and cactus type light source models. Physics Education, 57 (4), pp. 045022, 2022. (Type: Journal Article | Abstract | Links | BibTeX | Tags: External) @article{Özdemir2022, title = {Development of a virtual teaching environment with Algodoo: eye and cactus type light source models}, author = {Erdoğan Özdemir Coramik Mustafa}, url = {https://iopscience.iop.org/article/10.1088/1361-6552/ac60b0 https://iopscience.iop.org/article/10.1088/1361-6552/ac60b0/pdf?casa_token=V8xrPx7vhDAAAAAA:rPLZ6ro88reQ4VsHcF3r17FcMFZS5zgzLEr7VJMegEl3W8ni7Xy9hDyRQKmWdtQBQqQDDVQR}, doi = {10.1088/1361-6552/ac60b0}, year = {2022}, date = {2022-01-01}, journal = {Physics Education}, volume = {57}, number = {4}, pages = {045022}, abstract = {It is often necessary to enrich the teaching environment in order for students to learn optics in depth and to interpret the real optical situations with the information they have learned. In this study, a virtual teaching environment was developed using by Algodoo, a 2D simulation software. An eye model was created in order to explain the formation of the image in the eye in the teaching environment. Also, a cactus type light source model has also been developed to demonstrate that the image can be created in optics by using rays other than special rays. In order to show the success of the virtual teaching environment in modelling, previously known situations that the students had difficulty in understanding were simulated. Finally, some suggestions were made about the use of the virtual teaching environment. }, keywords = {External}, pubstate = {published}, tppubtype = {article} } It is often necessary to enrich the teaching environment in order for students to learn optics in depth and to interpret the real optical situations with the information they have learned. In this study, a virtual teaching environment was developed using by Algodoo, a 2D simulation software. An eye model was created in order to explain the formation of the image in the eye in the teaching environment. Also, a cactus type light source model has also been developed to demonstrate that the image can be created in optics by using rays other than special rays. In order to show the success of the virtual teaching environment in modelling, previously known situations that the students had difficulty in understanding were simulated. Finally, some suggestions were made about the use of the virtual teaching environment. |
2021 |
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![]() | Andersson, Jennifer; Servin, Martin: Predicting Gripability Heatmaps using Conditional GANs. Department of Physics. Umeå University Technical report, (diva2:1622970), 2021. (Type: Technical Report | Abstract | Links | BibTeX | Tags: External) @techreport{Andersson2021b, title = {Predicting Gripability Heatmaps using Conditional GANs}, author = {Jennifer Andersson and Martin Servin}, url = {https://www.diva-portal.org/smash/record.jsf?pid=diva2:1622970 https://www.diva-portal.org/smash/get/diva2:1622970/FULLTEXT01.pdf}, year = {2021}, date = {2021-12-15}, number = {diva2:1622970}, institution = {Department of Physics. Umeå University}, abstract = {The feasibility of using conditional GANs (Generative Adversarial Networks) to predict gripability in log piles is investigated. This is done by posing gripability heatmap prediction from RGB-D data as an image-to-image translation problem. Conditional GANs have previously achieved impressive results on several image-to-image translation tasks predicting physical properties and adding details not present in the input images. Here, piles of logs modelled as sticks or rods are generated in simulation, and groundtruth gripability maps are created using a simple algorithm streamlining the datacollection process. A modified SSIM (Structural Similarity Index) is used to evaluate the quality of the gripability heatmap predictions. The results indicate promising model performance on several different datasets and heatmap designs, including using base plane textures from a real forest production site to add realistic noise in the RGB data. Including a depth channel in the input data is shown to increase performance compared to using pure RGB data. The implementation is based on the general Pix2Pix network developed by Isola et al. in 2017. However, there is potential to increase performance and model generalization, and the adoption of more advanced loss functions and network architectures are suggested. Next steps include using terrains reconstructed from highdensity laser scans in physics-based simulation for data generation. A more in-depth discussion regarding the level of sophistication required in the gripability heatmaps should also be carried out, along with discussions regarding other specifications that will be required for future deployment. This will enable derivation of a tailored gripability metric for ground-truth heatmap generation, and method evaluation on less ideal data.}, type = {Technical report}, keywords = {External}, pubstate = {published}, tppubtype = {techreport} } The feasibility of using conditional GANs (Generative Adversarial Networks) to predict gripability in log piles is investigated. This is done by posing gripability heatmap prediction from RGB-D data as an image-to-image translation problem. Conditional GANs have previously achieved impressive results on several image-to-image translation tasks predicting physical properties and adding details not present in the input images. Here, piles of logs modelled as sticks or rods are generated in simulation, and groundtruth gripability maps are created using a simple algorithm streamlining the datacollection process. A modified SSIM (Structural Similarity Index) is used to evaluate the quality of the gripability heatmap predictions. The results indicate promising model performance on several different datasets and heatmap designs, including using base plane textures from a real forest production site to add realistic noise in the RGB data. Including a depth channel in the input data is shown to increase performance compared to using pure RGB data. The implementation is based on the general Pix2Pix network developed by Isola et al. in 2017. However, there is potential to increase performance and model generalization, and the adoption of more advanced loss functions and network architectures are suggested. Next steps include using terrains reconstructed from highdensity laser scans in physics-based simulation for data generation. A more in-depth discussion regarding the level of sophistication required in the gripability heatmaps should also be carried out, along with discussions regarding other specifications that will be required for future deployment. This will enable derivation of a tailored gripability metric for ground-truth heatmap generation, and method evaluation on less ideal data. |
![]() | Aoshima, Koji; Servin, Martin; Wadbro, Eddie: Simulation-Based Optimization of High-Performance Wheel Loading. Proceedings of the 38th International Symposium on Automation and Robotics in Construction (ISARC), International Association for Automation and Robotics in Construction (IAARC), 2021, ISBN: 978-952-69524-1-3. (Type: Conference | Abstract | Links | BibTeX | Tags: Algoryx, External) @conference{Aoshima2021, title = {Simulation-Based Optimization of High-Performance Wheel Loading}, author = {Koji Aoshima and Martin Servin and Eddie Wadbro}, editor = {Feng, Chen and Linner, Thomas and Brilakis, Ioannis and Castro, Daniel and Chen, Po-Han and Cho, Yong and Du, Jing and Ergan, Semiha and Garcia de Soto, Borja and Gaparík, Jozef and Habbal, Firas and Hammad, Amin and Iturralde, Kepa and Bock, Thomas and Kwon, Soonwook and Lafhaj, Zoubeir and Li, Nan and Liang, Ci-Jyun and Mantha, Bharadwaj and Ng, Ming Shan and Hall, Daniel and Pan, Mi and Pan, Wei and Rahimian, Farzad and Raphael, Benny and Sattineni, Anoop and Schlette, Christian and Shabtai, Isaac and Shen, Xuesong and Tang, Pingbo and Teizer, Jochen and Turkan, Yelda and Valero, Enrique and Zhu, Zhenhua}, url = {https://www.iaarc.org/publications/2021_proceedings_of_the_38th_isarc/simulation_based_optimization_of_high_performance_wheel_loading.html https://arxiv.org/abs/2107.14615 http://umit.cs.umu.se/hp_loading/}, doi = {10.22260/ISARC2021/009310.22260/ISARC2021/0093}, isbn = {978-952-69524-1-3}, year = {2021}, date = {2021-08-02}, booktitle = {Proceedings of the 38th International Symposium on Automation and Robotics in Construction (ISARC)}, pages = {688-695}, publisher = {International Association for Automation and Robotics in Construction (IAARC)}, abstract = {Having smart and autonomous earthmoving in mind, we explore high-performance wheel loading in a simulated environment. This paper introduces a wheel loader simulator that combines contacting 3D multibody dynamics with a hybrid continuum-particle terrain model, supporting realistic digging forces and soil displacements at real-time performance. A total of 270,000 simulations are run with different loading actions, pile slopes, and soil to analyze how they affect the loading performance. The results suggest that the preferred digging actions should preserve and exploit a steep pile slope. High digging speed favors high productivity, while energy-efficient loading requires a lower dig speed.}, howpublished = {38th International Symposium on Automation and Robotics in Construction (ISARC), Dubai, UAE (2021). arXiv:2107.14615 }, keywords = {Algoryx, External}, pubstate = {published}, tppubtype = {conference} } Having smart and autonomous earthmoving in mind, we explore high-performance wheel loading in a simulated environment. This paper introduces a wheel loader simulator that combines contacting 3D multibody dynamics with a hybrid continuum-particle terrain model, supporting realistic digging forces and soil displacements at real-time performance. A total of 270,000 simulations are run with different loading actions, pile slopes, and soil to analyze how they affect the loading performance. The results suggest that the preferred digging actions should preserve and exploit a steep pile slope. High digging speed favors high productivity, while energy-efficient loading requires a lower dig speed. |
![]() | Selby, Nicholas S; Asada, Harry H: Learning of Causal Observable Functions for Koopman-DFL Lifting Linearization of Nonlinear Controlled Systems and Its Application to Excavation Automation. IEEE Robotics and Automation Letters, 6 (4), pp. 6297 - 6304, 2021. (Type: Journal Article | Abstract | Links | BibTeX | Tags: External) @article{selby2021learning, title = {Learning of Causal Observable Functions for Koopman-DFL Lifting Linearization of Nonlinear Controlled Systems and Its Application to Excavation Automation}, author = {Nicholas S Selby and Harry H Asada}, url = {https://arxiv.org/abs/2104.02004 https://arxiv.org/pdf/2104.02004 }, doi = {https://doi.org/10.1109/LRA.2021.3092256}, year = {2021}, date = {2021-06-01}, journal = {IEEE Robotics and Automation Letters}, volume = {6}, number = {4}, pages = {6297 - 6304}, abstract = {Effective and causal observable functions for low-order lifting linearization of nonlinear controlled systems are learned from data by using neural networks. While Koopman operator theory allows us to represent a nonlinear system as a linear system in an infinite-dimensional space of observables, exact linearization is guaranteed only for autonomous systems with no input, and finding effective observable functions for approximation with a low-order linear system remains an open question. Dual-Faceted Linearization uses a set of effective observables for low-order lifting linearization, but the method requires knowledge of the physical structure of the nonlinear system. Here, a data-driven method is presented for generating a set of nonlinear observable functions that can accurately approximate a nonlinear control system to a low-order linear control system. A caveat in using data of measured variables as observables is that the measured variables may contain input to the system, which incurs a causality contradiction when lifting the system, i.e., taking derivatives of the observables. The current work presents a method for eliminating such anti-causal components of the observables and lifting the system using only causal observables. The method is applied to excavation automation, a complex nonlinear dynamical system, to obtain a low-order lifted linear model for control design.}, keywords = {External}, pubstate = {published}, tppubtype = {article} } Effective and causal observable functions for low-order lifting linearization of nonlinear controlled systems are learned from data by using neural networks. While Koopman operator theory allows us to represent a nonlinear system as a linear system in an infinite-dimensional space of observables, exact linearization is guaranteed only for autonomous systems with no input, and finding effective observable functions for approximation with a low-order linear system remains an open question. Dual-Faceted Linearization uses a set of effective observables for low-order lifting linearization, but the method requires knowledge of the physical structure of the nonlinear system. Here, a data-driven method is presented for generating a set of nonlinear observable functions that can accurately approximate a nonlinear control system to a low-order linear control system. A caveat in using data of measured variables as observables is that the measured variables may contain input to the system, which incurs a causality contradiction when lifting the system, i.e., taking derivatives of the observables. The current work presents a method for eliminating such anti-causal components of the observables and lifting the system using only causal observables. The method is applied to excavation automation, a complex nonlinear dynamical system, to obtain a low-order lifted linear model for control design. |
![]() | Susanti, D; Yaqiina, MH ; Maulana, S: Newton’s Gravity Interactive Simulation to Improve 10th-Grade Students’ Learning Outcome. Journal of Physics: Conference Series, 2377 (1), IOP Publishing, 2021. (Type: Conference | Links | BibTeX | Tags: External) @conference{susanti2022newton, title = {Newton’s Gravity Interactive Simulation to Improve 10th-Grade Students’ Learning Outcome}, author = {Susanti, D and Yaqiina, MH and Maulana, S}, url = {https://iopscience.iop.org/article/10.1088/1742-6596/2377/1/012091/meta}, year = {2021}, date = {2021-06-01}, booktitle = {Journal of Physics: Conference Series}, volume = {2377}, number = {1}, pages = {012091}, publisher = {IOP Publishing}, keywords = {External}, pubstate = {published}, tppubtype = {conference} } |
![]() | Shima, Daichi; Furukawa, Tomoyuki; Aoba, Ryuma; Ohashi, Ayato; Tsuruno, Kota; Naruse, Keitaro: Team Activity of Robot Competition of Simulated Robot in World Robot Summit 2020. SHS Web of Conferences, pp. 04016, EDP Sciences 2021, ISSN: 2261-2424. (Type: Inproceedings | Abstract | Links | BibTeX | Tags: External) @inproceedings{shima2021team, title = {Team Activity of Robot Competition of Simulated Robot in World Robot Summit 2020}, author = {Daichi Shima and Tomoyuki Furukawa and Ryuma Aoba and Ayato Ohashi and Kota Tsuruno and Keitaro Naruse}, url = {https://www.shs-conferences.org/articles/shsconf/abs/2021/13/shsconf_etltc2021_04016/shsconf_etltc2021_04016.html https://www.shs-conferences.org/articles/shsconf/pdf/2021/13/shsconf_etltc2021_04016.pdf }, issn = {2261-2424}, year = {2021}, date = {2021-05-08}, booktitle = {SHS Web of Conferences}, volume = {102}, pages = {04016}, organization = {EDP Sciences}, abstract = {World Robot Summit (WRS) has several robot competitions, and we will participate it in the infrastructure and disaster response category. Participating teams develop their robot system by teleoperation and/or autonomous operation and run it in a set of courses modelling and simplifying disaster responding situations. The authors will attend the challenge of the tunnel disaster response and recovery, in which we are requested to achieve an investigation and rescue scenario of a tunnel fire with simulated robots. As preparation, we develop simulated robot models and corresponding software as a team. In this article, we report out activity to the robot competition and student’s project-based learning by joining it.}, keywords = {External}, pubstate = {published}, tppubtype = {inproceedings} } World Robot Summit (WRS) has several robot competitions, and we will participate it in the infrastructure and disaster response category. Participating teams develop their robot system by teleoperation and/or autonomous operation and run it in a set of courses modelling and simplifying disaster responding situations. The authors will attend the challenge of the tunnel disaster response and recovery, in which we are requested to achieve an investigation and rescue scenario of a tunnel fire with simulated robots. As preparation, we develop simulated robot models and corresponding software as a team. In this article, we report out activity to the robot competition and student’s project-based learning by joining it. |
![]() | Gieselmann, Robert; Pokorny, Florian T: Planning-Augmented Hierarchical Reinforcement Learning. IEEE Robotics and Automation Letters, 6 (3), pp. 5097-5104, 2021. (Type: Journal Article | Abstract | Links | BibTeX | Tags: External) @article{Gieselmann2021, title = {Planning-Augmented Hierarchical Reinforcement Learning}, author = {Robert Gieselmann and Florian T Pokorny}, doi = {10.1109/LRA.2021.3071062}, year = {2021}, date = {2021-01-01}, journal = {IEEE Robotics and Automation Letters}, volume = {6}, number = {3}, pages = {5097-5104}, abstract = {Abstract—Planning algorithms are powerful at solving longhorizon decision-making problems but require that environment dynamics are known. Model-free reinforcement learning has recently been merged with graph-based planning to increase the robustness of trained policies in state-space navigation problems. Recent ideas suggest to use planning in order to provide intermediate waypoints guiding the policy in long-horizon tasks. Yet, it is not always practical to describe a problem in the setting of state-to-state navigation. Often, the goal is defined by one or multiple disjoint sets of valid states or implicitly using an abstract task description. Building upon previous efforts, we introduce a novel algorithm called Planning-Augmented Hierarchical Reinforcement Learning (PAHRL) which translates the concept of hybrid planning/RL to such problems with implicitly defined goal. Using a hierarchical framework, we divide the original task, formulated as a Markov Decision Process (MDP), into a hierarchy of shorter horizon MDPs. Actor-critic agents are trained in parallel for each level of the hierarchy. During testing, a planner then determines useful subgoals on a state graph constructed at the bottom level of the hierarchy. The effectiveness of our approach is demonstrated for a set of continuous control problems in simulation including robot arm reaching tasks and the manipulation of a deformable object.}, keywords = {External}, pubstate = {published}, tppubtype = {article} } Abstract—Planning algorithms are powerful at solving longhorizon decision-making problems but require that environment dynamics are known. Model-free reinforcement learning has recently been merged with graph-based planning to increase the robustness of trained policies in state-space navigation problems. Recent ideas suggest to use planning in order to provide intermediate waypoints guiding the policy in long-horizon tasks. Yet, it is not always practical to describe a problem in the setting of state-to-state navigation. Often, the goal is defined by one or multiple disjoint sets of valid states or implicitly using an abstract task description. Building upon previous efforts, we introduce a novel algorithm called Planning-Augmented Hierarchical Reinforcement Learning (PAHRL) which translates the concept of hybrid planning/RL to such problems with implicitly defined goal. Using a hierarchical framework, we divide the original task, formulated as a Markov Decision Process (MDP), into a hierarchy of shorter horizon MDPs. Actor-critic agents are trained in parallel for each level of the hierarchy. During testing, a planner then determines useful subgoals on a state graph constructed at the bottom level of the hierarchy. The effectiveness of our approach is demonstrated for a set of continuous control problems in simulation including robot arm reaching tasks and the manipulation of a deformable object. |
![]() | Styrud, Jonathan; Iovino, Matteo; Norrlöf, Mikael; Björkman, Mårten; Smith, Christian: Combining Planning and Learning of Behavior Trees for Robotic Assembly. arXiv preprint arXiv:2103.09036, 2021. (Type: Journal Article | Abstract | Links | BibTeX | Tags: External) @article{styrud2021combining, title = {Combining Planning and Learning of Behavior Trees for Robotic Assembly}, author = {Jonathan Styrud and Matteo Iovino and Mikael Norrlöf and Mårten Björkman and Christian Smith}, url = {https://arxiv.org/abs/2103.09036 https://arxiv.org/pdf/2103.09036 https://github.com/jstyrud/planning-and-learning }, year = {2021}, date = {2021-01-01}, journal = {arXiv preprint arXiv:2103.09036}, abstract = {Industrial robots can solve very complex tasks in controlled environments, but modern applications require robots able to operate in unpredictable surroundings as well. An increasingly popular reactive policy architecture in robotics is Behavior Trees but as with other architectures, programming time still drives cost and limits flexibility. There are two main branches of algorithms to generate policies automatically, automated planning and machine learning, both with their own drawbacks. We propose a method for generating Behavior Trees using a Genetic Programming algorithm and combining the two branches by taking the result of an automated planner and inserting it into the population. Experimental results confirm that the proposed method of combining planning and learning performs well on a variety of robotic assembly problems and outperforms both of the base methods used separately. We also show that this type of high level learning of Behavior Trees can be transferred to a real system without further training.}, keywords = {External}, pubstate = {published}, tppubtype = {article} } Industrial robots can solve very complex tasks in controlled environments, but modern applications require robots able to operate in unpredictable surroundings as well. An increasingly popular reactive policy architecture in robotics is Behavior Trees but as with other architectures, programming time still drives cost and limits flexibility. There are two main branches of algorithms to generate policies automatically, automated planning and machine learning, both with their own drawbacks. We propose a method for generating Behavior Trees using a Genetic Programming algorithm and combining the two branches by taking the result of an automated planner and inserting it into the population. Experimental results confirm that the proposed method of combining planning and learning performs well on a variety of robotic assembly problems and outperforms both of the base methods used separately. We also show that this type of high level learning of Behavior Trees can be transferred to a real system without further training. |
2020 |
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Li, Guoyuan; Waldum, Håkon Bjerkgaard; Grindvik, Marcus Olai; Jørundl, Ruben Svedal; Zhang, Houxiang: Development of a vision-based target exploration system for snake-like robots in structured environments. International Journal of Advanced Robotic Systems, pp. 1-11, 2020. (Type: Journal Article | Abstract | Links | BibTeX | Tags: External) @article{Li2020, title = {Development of a vision-based target exploration system for snake-like robots in structured environments}, author = {Guoyuan Li and Håkon Bjerkgaard Waldum and Marcus Olai Grindvik and Ruben Svedal Jørundl and Houxiang Zhang}, url = {https://journals.sagepub.com/doi/full/10.1177/1729881420936141 https://www.researchgate.net/publication/342710008_Development_of_a_vision-based_target_exploration_system_for_snake-like_robots_in_structured_environments}, doi = {10.1177/1729881420936141}, year = {2020}, date = {2020-07-06}, journal = {International Journal of Advanced Robotic Systems}, pages = {1-11}, abstract = {Applying snake-like robots to environmental exploration has been a hot topic for years. How to achieve free navigation for target search in a complex environment in a safe and efficient manner is one of the main tasks that researchers in the field of robotics currently face. This article presents a target exploration system that takes advantages of visual sensing to navigate the snake-like robot in structured environments. Two cameras are utilized in the system. The first one is mounted on the head of the snake-like robot for target recognition and the other is an overhead camera which is responsible for locating the robot and identifying surrounding obstacles. All dead ends in the environment can thus be recognized using a template-based method. A search strategy for traversal of the dead ends is employed for generating exploration paths. Several gaits are developed for the snake-like robot. By switching between these gaits, the snake-like robot is able to follow the paths to search for the target. Two experiments are conducted in a maze environment. The experimental results validate the effectiveness of the proposed system for snake-like robots exploring in structured environments.}, keywords = {External}, pubstate = {published}, tppubtype = {article} } Applying snake-like robots to environmental exploration has been a hot topic for years. How to achieve free navigation for target search in a complex environment in a safe and efficient manner is one of the main tasks that researchers in the field of robotics currently face. This article presents a target exploration system that takes advantages of visual sensing to navigate the snake-like robot in structured environments. Two cameras are utilized in the system. The first one is mounted on the head of the snake-like robot for target recognition and the other is an overhead camera which is responsible for locating the robot and identifying surrounding obstacles. All dead ends in the environment can thus be recognized using a template-based method. A search strategy for traversal of the dead ends is employed for generating exploration paths. Several gaits are developed for the snake-like robot. By switching between these gaits, the snake-like robot is able to follow the paths to search for the target. Two experiments are conducted in a maze environment. The experimental results validate the effectiveness of the proposed system for snake-like robots exploring in structured environments. | |
![]() | Borgström, Johan: Methodology for Real Time Simulations of Autonomous Utility Vehicles. 2020. (Type: Miscellaneous | Abstract | Links | BibTeX | Tags: External) @misc{borgstrom2020methodology, title = {Methodology for Real Time Simulations of Autonomous Utility Vehicles}, author = {Johan Borgström}, url = {http://ltu.diva-portal.org/smash/record.jsf?pid=diva2%3A1437952&dswid=-7032 http://ltu.diva-portal.org/smash/get/diva2:1437952/FULLTEXT02.pdf}, year = {2020}, date = {2020-01-01}, abstract = {This master thesis is a part of a research project where Luleå University of Technology (LTU) collaborates with University of Oulu, SINTEF Narvik and Oulu University of Applied Sciences. The goal with the research project is to develop a Nordic platform for development of autonomous, environmental friendly and energy efficient heavy vehicles in the forest, harbor and mining industry. The purpose with the master thesis is to assist LTU in their role in the research project. The Nordic platform was positioned in the product development process, with the result that it could be useful in the fourth phase ”Detail design” and in the fifth phase ”Testing and refinement” in the Ulrich and Eppinger product development process. A methodology has been developed, covering all necessary steps going from an assembly of a vehicle in an arbitrary CAD program to perform real time simulations (including HiL simulations) of the vehicle in Simulink. The off-road research platform for forest- and agriculture applications developed by LTU was used as a case study in the master thesis. Applying the methodology on this platform showed that choosing correct simulation frequency is important and that graphics enabled in real time simulations requires large computational power.}, keywords = {External}, pubstate = {published}, tppubtype = {misc} } This master thesis is a part of a research project where Luleå University of Technology (LTU) collaborates with University of Oulu, SINTEF Narvik and Oulu University of Applied Sciences. The goal with the research project is to develop a Nordic platform for development of autonomous, environmental friendly and energy efficient heavy vehicles in the forest, harbor and mining industry. The purpose with the master thesis is to assist LTU in their role in the research project. The Nordic platform was positioned in the product development process, with the result that it could be useful in the fourth phase ”Detail design” and in the fifth phase ”Testing and refinement” in the Ulrich and Eppinger product development process. A methodology has been developed, covering all necessary steps going from an assembly of a vehicle in an arbitrary CAD program to perform real time simulations (including HiL simulations) of the vehicle in Simulink. The off-road research platform for forest- and agriculture applications developed by LTU was used as a case study in the master thesis. Applying the methodology on this platform showed that choosing correct simulation frequency is important and that graphics enabled in real time simulations requires large computational power. |
![]() | Pereira, JG; Ellman, A: From CAD to Physics-Based Digital Twin: Framework for Real-Time Simulation of Virtual prototypes. Proceedings of the Design Society: DESIGN Conference, pp. 335–344, Cambridge University Press 2020. (Type: Inproceedings | Abstract | Links | BibTeX | Tags: External) @inproceedings{pereira2020cad, title = {From CAD to Physics-Based Digital Twin: Framework for Real-Time Simulation of Virtual prototypes}, author = {JG Pereira and A Ellman}, url = {https://www.cambridge.org/core/services/aop-cambridge-core/content/view/479604733E3644CA38B927FFCC09B519/S2633776220000473a.pdf/from-cad-to-physics-based-digital-twin-framework-for-real-time-simulation-of-virtual-prototypes.pdf}, doi = {doi:10.1017/dsd.2020.47}, year = {2020}, date = {2020-01-01}, booktitle = {Proceedings of the Design Society: DESIGN Conference}, volume = {1}, pages = {335--344}, organization = {Cambridge University Press}, abstract = {Engineering work is mostly done in 3D CAD software throughout the engineering process from conceptual design and layout of products. Physics-Based Virtual Prototypes are very valuable addition on Computer Aided Engineering enabling product development simulators, training simulators and digital twin concept in product lift-cycle process. In this work, we present a framework, how such virtual prototypes can be developed from 3D CAD models with meaningful effort.}, keywords = {External}, pubstate = {published}, tppubtype = {inproceedings} } Engineering work is mostly done in 3D CAD software throughout the engineering process from conceptual design and layout of products. Physics-Based Virtual Prototypes are very valuable addition on Computer Aided Engineering enabling product development simulators, training simulators and digital twin concept in product lift-cycle process. In this work, we present a framework, how such virtual prototypes can be developed from 3D CAD models with meaningful effort. |
![]() | Suzuki, Kenta; Kawabata, Kuniaki: Development of a simulator for underwater reconnaissance tasks by utilizing remotely operated robots. 2020 IEEE/SICE International Symposium on System Integration (SII), pp. 1100–1106, IEEE 2020. (Type: Inproceedings | Abstract | Links | BibTeX | Tags: External) @inproceedings{suzuki2020development, title = {Development of a simulator for underwater reconnaissance tasks by utilizing remotely operated robots}, author = {Kenta Suzuki and Kuniaki Kawabata}, doi = {10.1109/SII46433.2020.9026281}, year = {2020}, date = {2020-01-01}, booktitle = {2020 IEEE/SICE International Symposium on System Integration (SII)}, pages = {1100--1106}, organization = {IEEE}, abstract = {This paper describes the development of a simulator for underwater reconnaissance tasks by utilizing remotely operated robots. The developed simulator replicates physical effect such as fluid dynamics, buoyancy and fluid resistance in the area assumed to be filled with water. The simulated thrusters generate propulsion force and torque. The simulator also provides camera view disturbance models for a blur, distortion and noise. In this paper, we discussed the requirements to realistically simulate underwater remote reconnaissance tasks and explain the implementation methodologies. By using the developed simulator, we also demonstrate a simulation of a remotely operated vehicle (ROV) that was utilized in Fukushima Daiichi Nuclear Power Station (FDNPS).}, keywords = {External}, pubstate = {published}, tppubtype = {inproceedings} } This paper describes the development of a simulator for underwater reconnaissance tasks by utilizing remotely operated robots. The developed simulator replicates physical effect such as fluid dynamics, buoyancy and fluid resistance in the area assumed to be filled with water. The simulated thrusters generate propulsion force and torque. The simulator also provides camera view disturbance models for a blur, distortion and noise. In this paper, we discussed the requirements to realistically simulate underwater remote reconnaissance tasks and explain the implementation methodologies. By using the developed simulator, we also demonstrate a simulation of a remotely operated vehicle (ROV) that was utilized in Fukushima Daiichi Nuclear Power Station (FDNPS). |
![]() | Laezza, Rita; Karayiannidis, Yiannis: Shape Control of Elastoplastic Deformable Linear Objects through Reinforcement Learning. IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)
Las Vegas (Virtual), USA, 2020-10-25 - 2020-10-29, 2020. (Type: Conference | Abstract | Links | BibTeX | Tags: External) @conference{laezzashape2020, title = {Shape Control of Elastoplastic Deformable Linear Objects through Reinforcement Learning}, author = {Rita Laezza and Yiannis Karayiannidis}, url = {https://ras.papercept.net/proceedings/IROS20/3496.pdf}, year = {2020}, date = {2020-01-01}, booktitle = {IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS) Las Vegas (Virtual), USA, 2020-10-25 - 2020-10-29}, abstract = {Deformable object manipulation tasks have longbeen regarded as challenging robotic problems. However, untilrecently, very little work had been done on the subject, withmost robotic manipulation methods being developed for rigidobjects. As machine learning methods are becoming morepowerful, there are new model-free strategies to explore forthese objects, which are notoriously hard to model. This paperfocuses on shape control problems for Deformable Linear Objects (DLOs). Despite being one of the most researched classesof DLOs in terms of geometry, no other paper has focusedon materials with elastoplastic properties. Therefore, a novelshape control task, requiring permanent plastic deformationis implemented in a simulation environment. ReinforcementLearning methods are used to learn a continuous controlpolicy. To that end, a discrete curvature measure is usedas a low-dimensional state representation and as part of anintuitive reward function. Finally, three state-of-the-art actor-critic algorithms are compared on the proposed environmentand successfully achieve the goal shape.}, keywords = {External}, pubstate = {published}, tppubtype = {conference} } Deformable object manipulation tasks have longbeen regarded as challenging robotic problems. However, untilrecently, very little work had been done on the subject, withmost robotic manipulation methods being developed for rigidobjects. As machine learning methods are becoming morepowerful, there are new model-free strategies to explore forthese objects, which are notoriously hard to model. This paperfocuses on shape control problems for Deformable Linear Objects (DLOs). Despite being one of the most researched classesof DLOs in terms of geometry, no other paper has focusedon materials with elastoplastic properties. Therefore, a novelshape control task, requiring permanent plastic deformationis implemented in a simulation environment. ReinforcementLearning methods are used to learn a continuous controlpolicy. To that end, a discrete curvature measure is usedas a low-dimensional state representation and as part of anintuitive reward function. Finally, three state-of-the-art actor-critic algorithms are compared on the proposed environmentand successfully achieve the goal shape. |
![]() | Major, Pierre; Zhang, Houxiang; Hildre, Hans Petter; Edet, Mathieu: Virtual prototyping of offshore operations: a review. Ship Technology Research, pp. 1–18, 2020. (Type: Journal Article | Abstract | Links | BibTeX | Tags: External) @article{major2020virtual, title = {Virtual prototyping of offshore operations: a review}, author = {Pierre Major and Houxiang Zhang and Hans Petter Hildre and Mathieu Edet}, doi = {10.1080/09377255.2020.1831840}, year = {2020}, date = {2020-01-01}, journal = {Ship Technology Research}, pages = {1--18}, publisher = {Taylor & Francis}, abstract = {Virtual prototyping of offshore operations (VPOO) is performed to plan and validate planning of infrequent or demanding operations characterized by high risk and low margins of error in hostile and remote environments distant from emergency response bases that require expensive equipment. Key elements of VPOO is the rapidity of virtual prototyping and the human-centric approach necessitating high quality visuals and real-time time-domain simulation. This survey reviews publications, commercial software and simulators, and regulations on offshore operations. Findings indicate that the VPOO is not common in the industry, offshore operation regulations lag behind the state of the art in industry in terms of mission planning, and this field has been subject to scarce commercial and scientific scrutiny so far. A discussion of future developments and trends concludes the paper.}, keywords = {External}, pubstate = {published}, tppubtype = {article} } Virtual prototyping of offshore operations (VPOO) is performed to plan and validate planning of infrequent or demanding operations characterized by high risk and low margins of error in hostile and remote environments distant from emergency response bases that require expensive equipment. Key elements of VPOO is the rapidity of virtual prototyping and the human-centric approach necessitating high quality visuals and real-time time-domain simulation. This survey reviews publications, commercial software and simulators, and regulations on offshore operations. Findings indicate that the VPOO is not common in the industry, offshore operation regulations lag behind the state of the art in industry in terms of mission planning, and this field has been subject to scarce commercial and scientific scrutiny so far. A discussion of future developments and trends concludes the paper. |
![]() | Yuan, Shuai; Major, Pierre; Zhang, Houxiang: Flexible riser replacement operation based on advanced virtual prototyping. Ocean Engineering, 210 , pp. 107502, 2020. (Type: Journal Article | Abstract | Links | BibTeX | Tags: External) @article{yuan2020flexible, title = {Flexible riser replacement operation based on advanced virtual prototyping}, author = {Shuai Yuan and Pierre Major and Houxiang Zhang}, doi = {10.1016/j.oceaneng.2020.107502}, year = {2020}, date = {2020-01-01}, journal = {Ocean Engineering}, volume = {210}, pages = {107502}, publisher = {Elsevier}, abstract = {As a critical campaign in the offshore oil and gas engineering, flexible riser replacements involve complex operations that need to be optimized and detailed to factor in trends in the industry. Since it allows engineers to interact with simulation tools in real time during the operation design phase, virtual prototyping (VP) is an efficient method to obtain an optimal solution and improve operational procedures in terms of safety and effectiveness for risk-based integrity management of flexible risers. In this study, a real-time VP model is adopted to simulate the process of a water injection flexible riser pulled in from an installation vessel to a jacket platform, which is one of the riser replacements tasks. The results are validated against results based on a finite element analysis. Attention is paid to the configuration, tension, and maximum bending curvature along the flexible riser during the operation. The innovative approach presented in this paper can provide guidance with respect to the operation limitations of a flexible pipe in practical engineering.}, keywords = {External}, pubstate = {published}, tppubtype = {article} } As a critical campaign in the offshore oil and gas engineering, flexible riser replacements involve complex operations that need to be optimized and detailed to factor in trends in the industry. Since it allows engineers to interact with simulation tools in real time during the operation design phase, virtual prototyping (VP) is an efficient method to obtain an optimal solution and improve operational procedures in terms of safety and effectiveness for risk-based integrity management of flexible risers. In this study, a real-time VP model is adopted to simulate the process of a water injection flexible riser pulled in from an installation vessel to a jacket platform, which is one of the riser replacements tasks. The results are validated against results based on a finite element analysis. Attention is paid to the configuration, tension, and maximum bending curvature along the flexible riser during the operation. The innovative approach presented in this paper can provide guidance with respect to the operation limitations of a flexible pipe in practical engineering. |
![]() | Yang, Yajue; Pan, Jia; Long, Pinxin; Song, Xibin; Zhang, Liangjun: Time Variable Minimum Torque Trajectory Optimization for Autonomous Excavator. arXiv preprint arXiv:2006.00811, 2020. (Type: Journal Article | Abstract | Links | BibTeX | Tags: External) @article{yang2020time, title = {Time Variable Minimum Torque Trajectory Optimization for Autonomous Excavator}, author = {Yajue Yang and Jia Pan and Pinxin Long and Xibin Song and Liangjun Zhang}, url = {https://arxiv.org/abs/2006.00811 https://arxiv.org/pdf/2006.00811}, year = {2020}, date = {2020-01-01}, journal = {arXiv preprint arXiv:2006.00811}, abstract = {In this paper, we present a minimal torque and time variable trajectory optimization method for autonomous excavator considering the soil-tool interaction. The method formulates the excavation motion generation as a trajectory optimization problem and takes into account geometric, kinematic and dynamics constraints. To generate time-efficient trajectory and improve the overall optimization efficiency, we propose a time variable trajectory optimization mechanism so that the time intervals between the keypoints along the trajectory subject to the optimization. As a result, the method uses few keypoints and reduces the total number of optimization variables. We further introduce a soil-tool interaction force model, which considers the geometric shape of the bucket and the physical properties of the soil. The experimental result on a high fidelity dynamic simulator shows our method can generate feasible trajectories, which satisfy excavation task constraints and are adaptive to different soil conditions.}, keywords = {External}, pubstate = {published}, tppubtype = {article} } In this paper, we present a minimal torque and time variable trajectory optimization method for autonomous excavator considering the soil-tool interaction. The method formulates the excavation motion generation as a trajectory optimization problem and takes into account geometric, kinematic and dynamics constraints. To generate time-efficient trajectory and improve the overall optimization efficiency, we propose a time variable trajectory optimization mechanism so that the time intervals between the keypoints along the trajectory subject to the optimization. As a result, the method uses few keypoints and reduces the total number of optimization variables. We further introduce a soil-tool interaction force model, which considers the geometric shape of the bucket and the physical properties of the soil. The experimental result on a high fidelity dynamic simulator shows our method can generate feasible trajectories, which satisfy excavation task constraints and are adaptive to different soil conditions. |
![]() | Maruyama, T; Ogawa, S; Noda, K; Edaya, M; Jaklin, N; Tolsma, S; Takeda, N: Structural displacement compensation of a gigantic manipulator via deep learning. 2020 IEEE/SICE International Symposium on System Integration (SII), pp. 219–224, IEEE 2020. (Type: Inproceedings | Abstract | Links | BibTeX | Tags: External) @inproceedings{maruyama2020structural, title = {Structural displacement compensation of a gigantic manipulator via deep learning}, author = {T Maruyama and S Ogawa and K Noda and M Edaya and N Jaklin and S Tolsma and N Takeda}, doi = {10.1109/SII46433.2020.9026263}, year = {2020}, date = {2020-01-01}, booktitle = {2020 IEEE/SICE International Symposium on System Integration (SII)}, pages = {219--224}, organization = {IEEE}, abstract = {Structures of robotic systems that handle extremely heavy loads undergo static displacement. The ITER blanket remote handling system, which handles 4-ton objects, has displacements of up to 100 mm at the end effector. We propose a novel method that combines deep learning with a physics-based virtual reality system to compensate for displacement. Our deep learning model was trained by using data obtained from both the virtual reality system and physical measurement data of end effector positions. By using a prototype of the ITER blanket remote handling system, we experimentally show that our method successfully reduces the displacement at the end effector to a maximum error of 5.7 mm and a median error of 1.2 mm. We conclude that our approach provides an effective contribution to ensuring the feasibility and safety of the remote maintenance procedures that are to be performed within the ITER project.}, keywords = {External}, pubstate = {published}, tppubtype = {inproceedings} } Structures of robotic systems that handle extremely heavy loads undergo static displacement. The ITER blanket remote handling system, which handles 4-ton objects, has displacements of up to 100 mm at the end effector. We propose a novel method that combines deep learning with a physics-based virtual reality system to compensate for displacement. Our deep learning model was trained by using data obtained from both the virtual reality system and physical measurement data of end effector positions. By using a prototype of the ITER blanket remote handling system, we experimentally show that our method successfully reduces the displacement at the end effector to a maximum error of 5.7 mm and a median error of 1.2 mm. We conclude that our approach provides an effective contribution to ensuring the feasibility and safety of the remote maintenance procedures that are to be performed within the ITER project. |
2019 |
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![]() | Wang, Lin; Kim, Hyuncheol; Kim, Imgyu; Han, Soonhung: A visual simulation of ocean floating wind power system. Computer Animation and Virtual Worlds, 30 (2), pp. e1859, 2019. (Type: Journal Article | Abstract | Links | BibTeX | Tags: External) @article{wang2019visual, title = {A visual simulation of ocean floating wind power system}, author = {Lin Wang and Hyuncheol Kim and Imgyu Kim and Soonhung Han}, doi = {10.1002/cav.1859}, year = {2019}, date = {2019-01-01}, journal = {Computer Animation and Virtual Worlds}, volume = {30}, number = {2}, pages = {e1859}, publisher = {Wiley Online Library}, abstract = {The development of ocean floating wind power has been burgeoning in recent years because of its low cost and high efficiency. To facilitate effectiveness, 3D visualization using virtual reality and augmented reality technologies has been applied to many operating systems. However, most of the existing 3D motion visualizations are “pseudo” visualization, and there are a few realistic visualization systems that base the motion of ocean floating wind power on simulation and experiment results. Therefore, in this paper, we conducted research related to the design for a realistic motion visualization system based on numerical simulation data using a commercial game engine (Unity 3D). In our system, the six‐degree‐of‐freedom motion (Surge, Sway, Heave, Roll, Pitch, and Yaw) is simulated and visualized based on numerical analysis results of two hydrodynamics simulation softwares, which can illuminate the nuance between simulation results and experiment results and give us a “real‐time” visual experience about motion in each direction. Meanwhile, comprehensive sea environment conditions, such as wind, rain, water, sound, and cloudiness, are also visualized in Unity 3D.}, keywords = {External}, pubstate = {published}, tppubtype = {article} } The development of ocean floating wind power has been burgeoning in recent years because of its low cost and high efficiency. To facilitate effectiveness, 3D visualization using virtual reality and augmented reality technologies has been applied to many operating systems. However, most of the existing 3D motion visualizations are “pseudo” visualization, and there are a few realistic visualization systems that base the motion of ocean floating wind power on simulation and experiment results. Therefore, in this paper, we conducted research related to the design for a realistic motion visualization system based on numerical simulation data using a commercial game engine (Unity 3D). In our system, the six‐degree‐of‐freedom motion (Surge, Sway, Heave, Roll, Pitch, and Yaw) is simulated and visualized based on numerical analysis results of two hydrodynamics simulation softwares, which can illuminate the nuance between simulation results and experiment results and give us a “real‐time” visual experience about motion in each direction. Meanwhile, comprehensive sea environment conditions, such as wind, rain, water, sound, and cloudiness, are also visualized in Unity 3D. |
![]() | Major, Pierre; Skulstad, Robert; Li, Guoyuan; Zhang, Houxiang: Virtual prototyping: a case study of positioning systems for drilling operations in the Barents Sea. Ships and Offshore Structures, 14 (sup1), pp. 364–373, 2019. (Type: Journal Article | Abstract | Links | BibTeX | Tags: External) @article{major2019virtual, title = {Virtual prototyping: a case study of positioning systems for drilling operations in the Barents Sea}, author = {Pierre Major and Robert Skulstad and Guoyuan Li and Houxiang Zhang}, doi = {10.1080/17445302.2019.1601322}, year = {2019}, date = {2019-01-01}, journal = {Ships and Offshore Structures}, volume = {14}, number = {sup1}, pages = {364--373}, publisher = {Taylor & Francis}, abstract = {This study proposes a framework for comparative study on three different positioning solutions for mobile offshore drilling units (MODUs) using high modulus polyethylene (HMPE) ropes, including active mooring with an HMPE rope, conventional dynamic positioning (DP) and active hybrid position-keeping (AHP-K). The goal of the positioning systems is to keep the MODU above the wellhead with acceptable riser-angle loading, minimal energy consumption, reduced underwater noise generation, and harmful emissions. This is the first time a holistic study has been performed on positioning that factors in the financial and environmental costs. The time domain simulation, which includes sea-state, wind, and current profiles, is performed with a well-developed software architecture and control algorithms for MODU position-keeping. The case study addresses a MODU drilling in the Barents Sea. Simulation results show that AHP-K is more efficient compared to the other two positioning solutions for drilling operations in the studied environment.}, keywords = {External}, pubstate = {published}, tppubtype = {article} } This study proposes a framework for comparative study on three different positioning solutions for mobile offshore drilling units (MODUs) using high modulus polyethylene (HMPE) ropes, including active mooring with an HMPE rope, conventional dynamic positioning (DP) and active hybrid position-keeping (AHP-K). The goal of the positioning systems is to keep the MODU above the wellhead with acceptable riser-angle loading, minimal energy consumption, reduced underwater noise generation, and harmful emissions. This is the first time a holistic study has been performed on positioning that factors in the financial and environmental costs. The time domain simulation, which includes sea-state, wind, and current profiles, is performed with a well-developed software architecture and control algorithms for MODU position-keeping. The case study addresses a MODU drilling in the Barents Sea. Simulation results show that AHP-K is more efficient compared to the other two positioning solutions for drilling operations in the studied environment. |
![]() | Suzuki, Kenta; Kawabata, Kuniaki: Development of a multi-copter simulator and a projection system for virtual operation experience. 2019 IEEE/SICE International Symposium on System Integration (SII), pp. 1–6, IEEE 2019. (Type: Inproceedings | Abstract | Links | BibTeX | Tags: External) @inproceedings{suzuki2019development, title = {Development of a multi-copter simulator and a projection system for virtual operation experience}, author = {Kenta Suzuki and Kuniaki Kawabata}, doi = {10.1109/SII.2019.8700412}, year = {2019}, date = {2019-01-01}, booktitle = {2019 IEEE/SICE International Symposium on System Integration (SII)}, pages = {1--6}, organization = {IEEE}, abstract = {Our motivation is to utilize simulation technology to accelerate the decommissioning of Fukushima Daiichi Nuclear Power Station (FDNPS) by remote operated robots. We already developed several simulation functions in our previous work. Recently multi-copter was utilized for reconnaissance tasks at FDNPS. This paper described to design a simulation function for multi-copter operation training. Fluid dynamics affected to flying body are simulated by implemented function. We also attempt the demonstration of immersive operation environment based on a 3D projection system that provides virtual operation experience.}, keywords = {External}, pubstate = {published}, tppubtype = {inproceedings} } Our motivation is to utilize simulation technology to accelerate the decommissioning of Fukushima Daiichi Nuclear Power Station (FDNPS) by remote operated robots. We already developed several simulation functions in our previous work. Recently multi-copter was utilized for reconnaissance tasks at FDNPS. This paper described to design a simulation function for multi-copter operation training. Fluid dynamics affected to flying body are simulated by implemented function. We also attempt the demonstration of immersive operation environment based on a 3D projection system that provides virtual operation experience. |
![]() | Kanehiro, Fumio; Nakaoka, Shin’ichiro; Sugihara, Tomomichi; Wakisaka, Naoki; Ishigami, Genya; Ozaki, Shingo; Tadokoro, Satoshi: Simulator for disaster response robotics. S., Tadokoro (Ed.): Disaster Robotics, 128 , pp. 453–477, Springer, 2019. (Type: Incollection | Abstract | Links | BibTeX | Tags: External) @incollection{kanehiro2019simulator, title = {Simulator for disaster response robotics}, author = {Fumio Kanehiro and Shin’ichiro Nakaoka and Tomomichi Sugihara and Naoki Wakisaka and Genya Ishigami and Shingo Ozaki and Satoshi Tadokoro}, editor = {Tadokoro S. }, doi = {10.1007/978-3-030-05321-5_9}, year = {2019}, date = {2019-01-01}, booktitle = {Disaster Robotics}, volume = {128}, pages = {453--477}, publisher = {Springer}, series = {Springer Tracts in Advanced Robotics}, abstract = {This chapter presents a simulator for disaster response robots based on the Choreonoid framework. Two physics engines and a graphics engine were developed and integrated into the framework. One physics engine enables robust contact-force computation among rigid bodies based on volumetric intersection and a relaxed constraint, whereas the other enables accurate and computationally efficient computation of machine–terrain interaction mechanics based on macro and microscopic approaches. The graphics engine allows simulating natural phenomena, such as rain, fire, and smoke, based on a particle system to resemble tough scenarios at disaster sites. In addition, wide-angle vision sensors, such as omnidirectional cameras and LIDAR sensors, can be simulated using multiple rendering screens. Overall, the simulator provides a tool for the efficient and safe development of disaster response robots.}, keywords = {External}, pubstate = {published}, tppubtype = {incollection} } This chapter presents a simulator for disaster response robots based on the Choreonoid framework. Two physics engines and a graphics engine were developed and integrated into the framework. One physics engine enables robust contact-force computation among rigid bodies based on volumetric intersection and a relaxed constraint, whereas the other enables accurate and computationally efficient computation of machine–terrain interaction mechanics based on macro and microscopic approaches. The graphics engine allows simulating natural phenomena, such as rain, fire, and smoke, based on a particle system to resemble tough scenarios at disaster sites. In addition, wide-angle vision sensors, such as omnidirectional cameras and LIDAR sensors, can be simulated using multiple rendering screens. Overall, the simulator provides a tool for the efficient and safe development of disaster response robots. |
![]() | João, Pereira Jr: Development of a Harvester Machine Simulator in Virtual Reality. Faculty of Engineering and Natural Sciences, Tampere University, 2019. (Type: Masters Thesis | Abstract | Links | BibTeX | Tags: External) @mastersthesis{pereira2019development, title = {Development of a Harvester Machine Simulator in Virtual Reality}, author = {Pereira Jr João}, url = {https://trepo.tuni.fi/bitstream/handle/10024/115646/Pereira.pdf?sequence=2}, year = {2019}, date = {2019-01-01}, school = {Faculty of Engineering and Natural Sciences, Tampere University}, abstract = {Computer-aided design (CAD) software is used in the product design and development to design complex and detailed prototypes. It provides good assistance and solid data generation to designers and engineers. In order to remain competitive, industry is always seeking for higher process efficiency and product quality enhancement in the shortest period of time. Continuous research keeps going to make it possible. Virtual reality has been one of the research focus in the recent years. It is studied and applied to be used as an assistant tool in the product lifecyle management, particularly in facilitating the development phase. However, the implementation process from CAD to virtual reality remains a challenge due to time consumption and technology complexibility. In this work a real-time virtual reality harvester simulator was developed. The start point was a 3D harvester CAD model. It was used the CAD simulator AGX Momentum, a game engine Unity and the physics engine AGX Dynamics to create dynamics simulation, to design a virtual forest environment and to enable physical controllers interact with the model. With the capabilities of AGX Momentum, it was added dynamics motion directly in the CAD software, creating fast CAD simulations. A virtual scene was designed with Unity to simulate an environment and the immersion of the user on it with Oculus Rift device. The harvester model was imported to the Unity scene with AGX Dynamics. In the end it was obtained a real size virtual prototype, with the possibility of interacting and control it using physical controllers. The user can visualise the scene in real-time through a head mounted display, providing him the experience of a real machine operator. Driving the harvester in a simulated forest, allowed to test the model in a hypothetical real scenario. The process of implementing the CAD model in virtual reality used in this work, revealed to be efficient and intuitive. However, because it is a complex and large model, it was necessary to remove certain bodies (without dynamics effect) and reduce the number of contact points between components in order to balance the speed and performance of the simulator. Following the same method used in this work, Other CAD models can be imported to virtual reality and be dynamically simulated.}, keywords = {External}, pubstate = {published}, tppubtype = {mastersthesis} } Computer-aided design (CAD) software is used in the product design and development to design complex and detailed prototypes. It provides good assistance and solid data generation to designers and engineers. In order to remain competitive, industry is always seeking for higher process efficiency and product quality enhancement in the shortest period of time. Continuous research keeps going to make it possible. Virtual reality has been one of the research focus in the recent years. It is studied and applied to be used as an assistant tool in the product lifecyle management, particularly in facilitating the development phase. However, the implementation process from CAD to virtual reality remains a challenge due to time consumption and technology complexibility. In this work a real-time virtual reality harvester simulator was developed. The start point was a 3D harvester CAD model. It was used the CAD simulator AGX Momentum, a game engine Unity and the physics engine AGX Dynamics to create dynamics simulation, to design a virtual forest environment and to enable physical controllers interact with the model. With the capabilities of AGX Momentum, it was added dynamics motion directly in the CAD software, creating fast CAD simulations. A virtual scene was designed with Unity to simulate an environment and the immersion of the user on it with Oculus Rift device. The harvester model was imported to the Unity scene with AGX Dynamics. In the end it was obtained a real size virtual prototype, with the possibility of interacting and control it using physical controllers. The user can visualise the scene in real-time through a head mounted display, providing him the experience of a real machine operator. Driving the harvester in a simulated forest, allowed to test the model in a hypothetical real scenario. The process of implementing the CAD model in virtual reality used in this work, revealed to be efficient and intuitive. However, because it is a complex and large model, it was necessary to remove certain bodies (without dynamics effect) and reduce the number of contact points between components in order to balance the speed and performance of the simulator. Following the same method used in this work, Other CAD models can be imported to virtual reality and be dynamically simulated. |
2018 |
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![]() | Lenerand, Torstein Sundnes: Component-Based Simulator for Modelling the Design and Dynamics of Modular Robots. 2018. (Type: Masters Thesis | Abstract | Links | BibTeX | Tags: External) @mastersthesis{lenerand2018component, title = {Component-Based Simulator for Modelling the Design and Dynamics of Modular Robots}, author = {Torstein Sundnes Lenerand}, url = {http://hdl.handle.net/11250/2581432 https://ntnuopen.ntnu.no/ntnu-xmlui/bitstream/handle/11250/2581432/Lenerand%2c%20Torstein%20S.%202018.pdf?sequence=1&isAllowed=y}, year = {2018}, date = {2018-01-01}, abstract = {This project presents the design of a component-based simulator used for modelling the design and movement of chain-based modular robots. This work is in collaboration with NTNU Ålesund and implemented in the Unity® game engine with Algoryx® Dynamics for physics calculations. The focus is on Modular robots, along with techniques for simulator creation and software development such as Component-Based Software Engineering and Design. The Unified Process is used for prototyping and research, while the finished design is verified using tests, reviews, and use-case studies. This thesis discusses the impact of using Component-Based Design in a relatively small project, and the advantages/disadvantages of this decision. The goal is to provide the optimum tool for students to learn about, and researchers to develop, customized modular robots.}, keywords = {External}, pubstate = {published}, tppubtype = {mastersthesis} } This project presents the design of a component-based simulator used for modelling the design and movement of chain-based modular robots. This work is in collaboration with NTNU Ålesund and implemented in the Unity® game engine with Algoryx® Dynamics for physics calculations. The focus is on Modular robots, along with techniques for simulator creation and software development such as Component-Based Software Engineering and Design. The Unified Process is used for prototyping and research, while the finished design is verified using tests, reviews, and use-case studies. This thesis discusses the impact of using Component-Based Design in a relatively small project, and the advantages/disadvantages of this decision. The goal is to provide the optimum tool for students to learn about, and researchers to develop, customized modular robots. |
2017 |
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![]() | Hatledal, Lars Ivar; Zhang, Houxiang; Halse, Karl Henning; Hildre, Hans Petter: Numerical study for a catamaran gripper-monopile mechanism of a novel offshore wind turbine assembly installation procedure. ASME 2017 36th International Conference on Ocean, Offshore and Arctic Engineering, American Society of Mechanical Engineers Digital Collection 2017. (Type: Inproceedings | Abstract | Links | BibTeX | Tags: External) @inproceedings{hatledal2017numerical, title = {Numerical study for a catamaran gripper-monopile mechanism of a novel offshore wind turbine assembly installation procedure}, author = {Lars Ivar Hatledal and Houxiang Zhang and Karl Henning Halse and Hans Petter Hildre}, url = {https://www.semanticscholar.org/paper/Numerical-Study-for-a-Catamaran-Gripper-Monopile-of-Hatledal-Zhang/cc2cd384a1d1b1a36cab675be59b6aecc7e6432c?p2df}, doi = {10.1115/OMAE2017-62342}, year = {2017}, date = {2017-01-01}, booktitle = {ASME 2017 36th International Conference on Ocean, Offshore and Arctic Engineering}, organization = {American Society of Mechanical Engineers Digital Collection}, abstract = {Current methods for installation of offshore wind turbines are all sensitive to the weather conditions and the present cost level of offshore wind power is more than twice the cost of land-based units, increasing with water depth. This paper presents numerical simulations of a novel experimental gripper design to reduce the environmental effects applied to a catamaran type of vessel during wind turbine installation. In SFI MOVE project in NTNU Aalesund, our team proposed a novel wind turbine installation process. A new catamaran vessel will carry pre-assembled wind turbines to the installation location. Two new designed grippers on the deck will make a lifting operation to install the wind turbine onto the turbine foundation. Three prismatic grippers with several rolling contact points at the end are attached in an arc at the catamaran’s aft, designed to grasp the turbine foundation in order to make a connection between the two in the horizontal plane. This paper will only emphasize the contact responses between the turbine foundation and the three grippers during the wind turbine installation process. Numerical simulations are carried out using the virtual prototyping framework Vicosim which is developed by NTNU Aalesund. The simulation results show validation of a key part of the proposed new wind turbine installation idea.}, keywords = {External}, pubstate = {published}, tppubtype = {inproceedings} } Current methods for installation of offshore wind turbines are all sensitive to the weather conditions and the present cost level of offshore wind power is more than twice the cost of land-based units, increasing with water depth. This paper presents numerical simulations of a novel experimental gripper design to reduce the environmental effects applied to a catamaran type of vessel during wind turbine installation. In SFI MOVE project in NTNU Aalesund, our team proposed a novel wind turbine installation process. A new catamaran vessel will carry pre-assembled wind turbines to the installation location. Two new designed grippers on the deck will make a lifting operation to install the wind turbine onto the turbine foundation. Three prismatic grippers with several rolling contact points at the end are attached in an arc at the catamaran’s aft, designed to grasp the turbine foundation in order to make a connection between the two in the horizontal plane. This paper will only emphasize the contact responses between the turbine foundation and the three grippers during the wind turbine installation process. Numerical simulations are carried out using the virtual prototyping framework Vicosim which is developed by NTNU Aalesund. The simulation results show validation of a key part of the proposed new wind turbine installation idea. |
![]() | Nakaoka, Shiníchiro; Cisneros, Rafael; Morisawa, Mitsuharu; Sakaguchi, Takeshi; Kaneko, Kenji; Kajita, Shuuji; Kanehiro, Fumio: Developing semi-autonomous humanoid robots that perform various composite tasks via a task sequencer and dynamics simulator. 2017 IEEE Workshop on Advanced Robotics and its Social Impacts (ARSO), pp. 1–8, IEEE 2017. (Type: Inproceedings | Abstract | Links | BibTeX | Tags: External) @inproceedings{nakaoka2017developing, title = {Developing semi-autonomous humanoid robots that perform various composite tasks via a task sequencer and dynamics simulator}, author = {Shiníchiro Nakaoka and Rafael Cisneros and Mitsuharu Morisawa and Takeshi Sakaguchi and Kenji Kaneko and Shuuji Kajita and Fumio Kanehiro}, doi = {10.1109/ARSO.2017.8025188}, year = {2017}, date = {2017-01-01}, booktitle = {2017 IEEE Workshop on Advanced Robotics and its Social Impacts (ARSO)}, pages = {1--8}, organization = {IEEE}, abstract = {This paper proposes a system to enable a humanoid robot to perform various tasks semi-autonomously according to higher-layer procedures called task sequences. A task sequence is a sequentially structured procedure that describes how to perform a particular task based on sensing data, motion planners, and a robot controller. These task sequences are processed by the task sequencer to move the robot. The goal of our system is to support comprehensive tasks, such as disaster response, with a number of task sequences defined for various subtasks. To efficiently develop required task sequences, the task sequencer is designed such that task sequences can be executed interactively; further, the task sequencer is integrated with a dynamics simulator that can be used to test the sequences without actually moving the robot. We verified our system by using it to make our HRP-2Kai robot perform the tasks defined in the DARPA Robotics Challenge, a competition involving disaster response robots.}, keywords = {External}, pubstate = {published}, tppubtype = {inproceedings} } This paper proposes a system to enable a humanoid robot to perform various tasks semi-autonomously according to higher-layer procedures called task sequences. A task sequence is a sequentially structured procedure that describes how to perform a particular task based on sensing data, motion planners, and a robot controller. These task sequences are processed by the task sequencer to move the robot. The goal of our system is to support comprehensive tasks, such as disaster response, with a number of task sequences defined for various subtasks. To efficiently develop required task sequences, the task sequencer is designed such that task sequences can be executed interactively; further, the task sequencer is integrated with a dynamics simulator that can be used to test the sequences without actually moving the robot. We verified our system by using it to make our HRP-2Kai robot perform the tasks defined in the DARPA Robotics Challenge, a competition involving disaster response robots. |
![]() | Li, Guoyuan; Urbina, Rodrigo; Zhang, Houxiang; Gomez, Juan G: Concept design and simulation of a water proofing modular robot for amphibious locomotion. 2017 International Conference on Advanced Mechatronic Systems (ICAMechS), pp. 145–150, IEEE 2017. (Type: Inproceedings | Abstract | Links | BibTeX | Tags: External) @inproceedings{li2017concept, title = {Concept design and simulation of a water proofing modular robot for amphibious locomotion}, author = {Guoyuan Li and Rodrigo Urbina and Houxiang Zhang and Juan G Gomez}, doi = {10.1109/ICAMechS.2017.8316566}, year = {2017}, date = {2017-01-01}, booktitle = {2017 International Conference on Advanced Mechatronic Systems (ICAMechS)}, pages = {145--150}, organization = {IEEE}, abstract = {This paper will introduce a novel adaptive modular robot for amphibious locomotion research. First, an overview of modular robotic research is given systematically. In this project, we concentrate on designing a new kind of modular robot with a central part and adaptable covers, so to build different configurations. The assemble prototypes could be used for bio-inspired locomotion research not only on ground, but also in water. The modular design, interfaces, and different configurations will be presented throughout. After that, related simulations including locomotion and swimming are shown to confirm the concept and principle. In the end, a conclusion is given and future work is outlined.}, keywords = {External}, pubstate = {published}, tppubtype = {inproceedings} } This paper will introduce a novel adaptive modular robot for amphibious locomotion research. First, an overview of modular robotic research is given systematically. In this project, we concentrate on designing a new kind of modular robot with a central part and adaptable covers, so to build different configurations. The assemble prototypes could be used for bio-inspired locomotion research not only on ground, but also in water. The modular design, interfaces, and different configurations will be presented throughout. After that, related simulations including locomotion and swimming are shown to confirm the concept and principle. In the end, a conclusion is given and future work is outlined. |
2016 |
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![]() | Park, Kwang-Phil; Ham, Seung-Ho; Lee, Chan-Young: Application and validation of production planning simulation in shipbuilding. Ocean Engineering, 114 , pp. 154–167, 2016. (Type: Journal Article | Abstract | Links | BibTeX | Tags: External) @article{park2016application, title = {Application and validation of production planning simulation in shipbuilding}, author = {Kwang-Phil Park and Seung-Ho Ham and Chan-Young Lee}, doi = {10.1016/j.oceaneng.2016.01.008}, year = {2016}, date = {2016-01-01}, journal = {Ocean Engineering}, volume = {114}, pages = {154--167}, publisher = {Elsevier}, abstract = {As the weight and size of assembly blocks are getting increased, new production procedures by using floating cranes have been proposed to enhance the efficiency in shipyards. In this situation, simulation technology is required to evaluate potential risks of the procedure in advance. By such a necessity, we have developed a simulation system, named SIMSON (SIMulation System Of New production planning). SIMSON calculates the motion of the lifted block and floating bodies such as vessels and floating cranes based on the multibody system dynamics with the hydrostatic and hydrodynamic forces. The calculated motion and wire rope tension are used for dynamic effect estimation. In this paper, we present the application cases of SIMSON to real production process. The simulation results are compared by observing the situation in the real operations. The observation illustrates the simulation results are in harmony with the real situation and the application of SIMSON to production planning simulation in shipyards is quite feasible.}, keywords = {External}, pubstate = {published}, tppubtype = {article} } As the weight and size of assembly blocks are getting increased, new production procedures by using floating cranes have been proposed to enhance the efficiency in shipyards. In this situation, simulation technology is required to evaluate potential risks of the procedure in advance. By such a necessity, we have developed a simulation system, named SIMSON (SIMulation System Of New production planning). SIMSON calculates the motion of the lifted block and floating bodies such as vessels and floating cranes based on the multibody system dynamics with the hydrostatic and hydrodynamic forces. The calculated motion and wire rope tension are used for dynamic effect estimation. In this paper, we present the application cases of SIMSON to real production process. The simulation results are compared by observing the situation in the real operations. The observation illustrates the simulation results are in harmony with the real situation and the application of SIMSON to production planning simulation in shipyards is quite feasible. |
![]() | He, Dahai: Virtual Winch Prototyping-Design, Modeling, Simulation and Testing of A Marine Hydraulic Winch System with Active Heave Compensation.. 2016. (Type: Masters Thesis | Abstract | Links | BibTeX | Tags: External) @mastersthesis{he2016virtual, title = {Virtual Winch Prototyping-Design, Modeling, Simulation and Testing of A Marine Hydraulic Winch System with Active Heave Compensation.}, author = {Dahai He}, url = {https://ntnuopen.ntnu.no/ntnu-xmlui/bitstream/handle/11250/2417673/He%2c%20D.%202016.pdf?sequence=1&isAllowed=y https://ntnuopen.ntnu.no/ntnu-xmlui/handle/11250/2417673 http://hdl.handle.net/11250/2417673}, year = {2016}, date = {2016-01-01}, abstract = {This thesis is to develop a standard virtual prototyping system for hydraulic winch system including developing a library of standard sub-models of hydraulic system, mechanical system and control system (AHC), and visualizing the simulation and operation of the virtual winch prototyping system. To be more specific: Chapter 1. Motivation and background of winch prototyping is introduced so as to break down the problems and formulate the objectives of this projects. Chapter 2. Theoretical background is shown in this part. It contains the briefly descriptions of the important theory applied in virtual prototyping winch system. Chapter 3. Methodology is shown in this part. It contains the detailed theory basis applied in the modelling of hydraulic and mechanical sub-systems of winch system. Chapter 4. This chapter describes the implementation of mechanical sub-system. 3D modelling, parameterization and visualization are implemented by using WebGL technology with three.js library. The outcome of the mechanical part can be easily integrated into the virtual prototyping framework. Chapter 5. This chapter elaborates the method and the process of hydraulic and control (AHC) sub-model modelling. Bond graph theory is applied during the modelling process. Different alternatives of hydraulic system structure are analysed and compared to finalize a better solution of hydraulic system structure. Chapter 6: This chapter explains the integration method of virtual prototyping winch system framework. Chapter 7: Results of mechanical modelling, hydraulic with control modelling and co-simulation of integrated virtual prototyping winch system are shown and discussed to evaluate the performance of virtual prototyping system. Chapter 8: This part makes conclusions, modelling alternatives and future work for the virtual prototyping winch system.}, keywords = {External}, pubstate = {published}, tppubtype = {mastersthesis} } This thesis is to develop a standard virtual prototyping system for hydraulic winch system including developing a library of standard sub-models of hydraulic system, mechanical system and control system (AHC), and visualizing the simulation and operation of the virtual winch prototyping system. To be more specific: Chapter 1. Motivation and background of winch prototyping is introduced so as to break down the problems and formulate the objectives of this projects. Chapter 2. Theoretical background is shown in this part. It contains the briefly descriptions of the important theory applied in virtual prototyping winch system. Chapter 3. Methodology is shown in this part. It contains the detailed theory basis applied in the modelling of hydraulic and mechanical sub-systems of winch system. Chapter 4. This chapter describes the implementation of mechanical sub-system. 3D modelling, parameterization and visualization are implemented by using WebGL technology with three.js library. The outcome of the mechanical part can be easily integrated into the virtual prototyping framework. Chapter 5. This chapter elaborates the method and the process of hydraulic and control (AHC) sub-model modelling. Bond graph theory is applied during the modelling process. Different alternatives of hydraulic system structure are analysed and compared to finalize a better solution of hydraulic system structure. Chapter 6: This chapter explains the integration method of virtual prototyping winch system framework. Chapter 7: Results of mechanical modelling, hydraulic with control modelling and co-simulation of integrated virtual prototyping winch system are shown and discussed to evaluate the performance of virtual prototyping system. Chapter 8: This part makes conclusions, modelling alternatives and future work for the virtual prototyping winch system. |
![]() | Li, Guoyuan; Skogeng, Pedersen Birger; Deng, Yuxiang; Hatledal, Lars Ivar; Zhang, Houxiang: Towards a virtual prototyping framework for ship maneuvering in offshore operations. OCEANS 2016-Shanghai, pp. 1–6, IEEE 2016. (Type: Inproceedings | Abstract | Links | BibTeX | Tags: External) @inproceedings{li2016towards, title = {Towards a virtual prototyping framework for ship maneuvering in offshore operations}, author = {Guoyuan Li and Pedersen Birger Skogeng and Yuxiang Deng and Lars Ivar Hatledal and Houxiang Zhang}, url = {https://folk.ntnu.no/gulj/myPaper/2016_li_towards.pdf}, year = {2016}, date = {2016-01-01}, booktitle = {OCEANS 2016-Shanghai}, pages = {1--6}, organization = {IEEE}, abstract = {This paper presents a virtual prototyping framework that can achieve modeling, simulation and control for ship maneuvering in offshore operations. To fast construct scenario for certain ship maneuvering tasks, a scenario editor is designed to model the ship, the environment disturbances and the scene, respectively. The corresponding scenario containing physical properties is built up in a physics simulation engine AgX. A graphical user interface responsible for visualizing the simulation and plotting data in a real-time manner is developed, in which dynamic interaction including manual control, failure/recover of thrusters and weather change is implemented. Taking advantages of a distributed communication architecture, the plug-in control mechanism is realized to increase the flexibility for evaluating ship maneuvering performance. Through a case study of trajectory tracking, the framework is verified efficient in constructing scenario and testing control model for ship maneuvering applications.}, keywords = {External}, pubstate = {published}, tppubtype = {inproceedings} } This paper presents a virtual prototyping framework that can achieve modeling, simulation and control for ship maneuvering in offshore operations. To fast construct scenario for certain ship maneuvering tasks, a scenario editor is designed to model the ship, the environment disturbances and the scene, respectively. The corresponding scenario containing physical properties is built up in a physics simulation engine AgX. A graphical user interface responsible for visualizing the simulation and plotting data in a real-time manner is developed, in which dynamic interaction including manual control, failure/recover of thrusters and weather change is implemented. Taking advantages of a distributed communication architecture, the plug-in control mechanism is realized to increase the flexibility for evaluating ship maneuvering performance. Through a case study of trajectory tracking, the framework is verified efficient in constructing scenario and testing control model for ship maneuvering applications. |
2015 |
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![]() | Hatledal, Lars Ivar; Schaathun, Hans Georg; Zhang, Houxiang: A software architecture for simulation and visualisation based on the functional mock-up interface and web technologies. Proceedings of The 57th Conference on Simulation and Modelling (SIMS 56): October, 7-9, 2015, Linköping University, Sweden, Linköping University Electronic Press, Linköpings universitet 2015. (Type: Inproceedings | Abstract | Links | BibTeX | Tags: External) @inproceedings{hatledal2015software, title = {A software architecture for simulation and visualisation based on the functional mock-up interface and web technologies}, author = {Lars Ivar Hatledal and Hans Georg Schaathun and Houxiang Zhang}, url = {https://www.researchgate.net/profile/Hans-Georg-Schaathun/publication/300217936_A_Software_Architecture_for_Simulation_and_Visualisation_based_on_the_Functional_Mock-up_Interface_and_Web_Technologies/links/575a9bc108aec91374a603fd/A-Software-Architecture-for-Simulation-and-Visualisation-based-on-the-Functional-Mock-up-Interface-and-Web-Technologies.pdf }, doi = {10.3384/ecp15119123}, year = {2015}, date = {2015-01-01}, booktitle = {Proceedings of The 57th Conference on Simulation and Modelling (SIMS 56): October, 7-9, 2015, Linköping University, Sweden}, organization = {Linköping University Electronic Press, Linköpings universitet}, abstract = {This paper presents a software architecture for a collabora-tive virtual environment (CVE) for simulation and visual-isation based on the Functional Mock-up Interface (FMI)for co-simulation and web technologies. FMI has beenchosen in order to have a standardised and independentinterface to models created in different modelling tools.The user interface has been implemented using webtechnologies, which enables a very high degree of flexi-bility. The Web Graphics Library (WebGL) is used for in-teractive 3D visualisations, enabling native cross-platformrendering directly in the browser without the need ofinstalling any additional plug-ins. Employing the bi-directional communication capabilities of the WebSocketprotocol, multiple users can interact with the same simu-lation models simultaneously.A software prototype has been developed in order todemonstrate the applicability of the proposed architecture.As a case study, we have considered virtual prototypingof marine cranes, to illustrate the use on real world prob-lems.}, keywords = {External}, pubstate = {published}, tppubtype = {inproceedings} } This paper presents a software architecture for a collabora-tive virtual environment (CVE) for simulation and visual-isation based on the Functional Mock-up Interface (FMI)for co-simulation and web technologies. FMI has beenchosen in order to have a standardised and independentinterface to models created in different modelling tools.The user interface has been implemented using webtechnologies, which enables a very high degree of flexi-bility. The Web Graphics Library (WebGL) is used for in-teractive 3D visualisations, enabling native cross-platformrendering directly in the browser without the need ofinstalling any additional plug-ins. Employing the bi-directional communication capabilities of the WebSocketprotocol, multiple users can interact with the same simu-lation models simultaneously.A software prototype has been developed in order todemonstrate the applicability of the proposed architecture.As a case study, we have considered virtual prototypingof marine cranes, to illustrate the use on real world prob-lems. |
2014 |
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![]() | Metrikin, Ivan: A software framework for simulating stationkeeping of a vessel in discontinuous ice. Modeling, Identification and Control 2014, pp. 211–248, Norsk Forening for Automatisering, 2014. (Type: Inproceedings | Abstract | Links | BibTeX | Tags: External) @inproceedings{metrikin2014software, title = {A software framework for simulating stationkeeping of a vessel in discontinuous ice}, author = {Ivan Metrikin}, url = {https://ntnuopen.ntnu.no/ntnu-xmlui/bitstream/handle/11250/2392045/MIC-2014-4-2%2b-%2bMetrikin.pdf?sequence=3&isAllowed=y http://hdl.handle.net/11250/2392045}, doi = {10.4173/mic.2014.4.2}, year = {2014}, date = {2014-01-01}, booktitle = {Modeling, Identification and Control 2014}, volume = {35}, number = {4}, pages = {211--248}, publisher = {Norsk Forening for Automatisering}, abstract = {This paper describes a numerical package for simulating stationkeeping operations of an offshore vessel in floating sea ice. The software has found broad usage in both academic and industrial projects related to design and operations of floating structures in the Arctic. Interactions with both intact and broken ice conditions can be simulated by the numerical tool, but the main emphasis is placed on modelling managed ice environments relevant for prospective petroleum industry operations in the Arctic. The paper gives a thorough description of the numerical tool from both theoretical and software implementation perspectives. Structural meshing, ice field generation, multibody modelling and ice breaking aspects of the model are presented and discussed. Finally, the main assumptions and limitations of the computational techniques are elucidated and further work directions are suggested.}, keywords = {External}, pubstate = {published}, tppubtype = {inproceedings} } This paper describes a numerical package for simulating stationkeeping operations of an offshore vessel in floating sea ice. The software has found broad usage in both academic and industrial projects related to design and operations of floating structures in the Arctic. Interactions with both intact and broken ice conditions can be simulated by the numerical tool, but the main emphasis is placed on modelling managed ice environments relevant for prospective petroleum industry operations in the Arctic. The paper gives a thorough description of the numerical tool from both theoretical and software implementation perspectives. Structural meshing, ice field generation, multibody modelling and ice breaking aspects of the model are presented and discussed. Finally, the main assumptions and limitations of the computational techniques are elucidated and further work directions are suggested. |
2012 |
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Metrikin, Ivan; Lu, Wenjun; Lubbad, Raed; Løset, Sveinung; Kashafutdinov, Marat: Numerical Simulation of a Floater in a Broken-Ice Field: Part I—Model Description. International Conference on Offshore Mechanics and Arctic Engineering, pp. 579–588, American Society of Mechanical Engineers 2012. (Type: Inproceedings | Abstract | Links | BibTeX | Tags: External) @inproceedings{metrikin2012numerical, title = {Numerical Simulation of a Floater in a Broken-Ice Field: Part I—Model Description}, author = {Ivan Metrikin and Wenjun Lu and Raed Lubbad and Sveinung Løset and Marat Kashafutdinov}, doi = {10.1115/OMAE2012-83938}, year = {2012}, date = {2012-01-01}, booktitle = {International Conference on Offshore Mechanics and Arctic Engineering}, volume = {44939}, pages = {579--588}, organization = {American Society of Mechanical Engineers}, abstract = {This paper presents a novel concept for simulating the ice-floater interaction process. The concept is based on a mathematical model which emphasizes the station-keeping scenario, i.e. when the relative velocity between the floater and the ice is comparatively small. This means that the model is geared towards such applications as dynamic positioning in ice and ice management. The concept is based on coupling the rigid multibody simulations with the Finite Element Method (FEM) simulations. The rigid multibody simulation is implemented through a physics engine which is used to model the dynamic behaviour of rigid bodies which undergo large translational and rotational displacements (the floater and the ice floes). The FEM is used to simulate the material behaviour of the ice and the fluid, i.e. the ice breaking and the hydrodynamics of the ice floes. Within this framework, the physics engine is responsible for dynamically detecting the contacts between the objects in the calculation domain, and the FEM software is responsible for calculating the contact forces. The concept is applicable for simulations in a three-dimensional space (3D). The model described in this paper is divided into two main parts: the mathematical ice model and the mathematical floater model. The mathematical ice model allows modelling both intact level ice and discontinuous ice within a single framework. However, the primary focus of this paper is placed on modelling the broken ice conditions. A floater is modelled as a rigid body with 6 degrees of freedom, i.e. no deformations of the floater’s hull are allowed. Nevertheless, the hydrodynamics of the floater and the ice is considered within the outlined model. The presented approach allows implementing realistic, high fidelity 3D simulations of the ice-fluid-structure interaction process.}, keywords = {External}, pubstate = {published}, tppubtype = {inproceedings} } This paper presents a novel concept for simulating the ice-floater interaction process. The concept is based on a mathematical model which emphasizes the station-keeping scenario, i.e. when the relative velocity between the floater and the ice is comparatively small. This means that the model is geared towards such applications as dynamic positioning in ice and ice management. The concept is based on coupling the rigid multibody simulations with the Finite Element Method (FEM) simulations. The rigid multibody simulation is implemented through a physics engine which is used to model the dynamic behaviour of rigid bodies which undergo large translational and rotational displacements (the floater and the ice floes). The FEM is used to simulate the material behaviour of the ice and the fluid, i.e. the ice breaking and the hydrodynamics of the ice floes. Within this framework, the physics engine is responsible for dynamically detecting the contacts between the objects in the calculation domain, and the FEM software is responsible for calculating the contact forces. The concept is applicable for simulations in a three-dimensional space (3D). The model described in this paper is divided into two main parts: the mathematical ice model and the mathematical floater model. The mathematical ice model allows modelling both intact level ice and discontinuous ice within a single framework. However, the primary focus of this paper is placed on modelling the broken ice conditions. A floater is modelled as a rigid body with 6 degrees of freedom, i.e. no deformations of the floater’s hull are allowed. Nevertheless, the hydrodynamics of the floater and the ice is considered within the outlined model. The presented approach allows implementing realistic, high fidelity 3D simulations of the ice-fluid-structure interaction process. | |
Metrikin, Ivan; Borzov, Andrey; Lubbad, Raed; Løset, Sveinung: Numerical simulation of a floater in a broken-ice field: Part II—Comparative study of physics engines. International Conference on Offshore Mechanics and Arctic Engineering, pp. 477–486, American Society of Mechanical Engineers 2012. (Type: Inproceedings | Abstract | Links | BibTeX | Tags: External) @inproceedings{metrikin2012numericalb, title = {Numerical simulation of a floater in a broken-ice field: Part II—Comparative study of physics engines}, author = {Ivan Metrikin and Andrey Borzov and Raed Lubbad and Sveinung Løset}, doi = {10.1115/OMAE2012-83430}, year = {2012}, date = {2012-01-01}, booktitle = {International Conference on Offshore Mechanics and Arctic Engineering}, volume = {44939}, pages = {477--486}, organization = {American Society of Mechanical Engineers}, abstract = {Numerical simulation of a floater in ice-infested waters can be performed using a physics engine. This software can dynamically detect contacts and calculate the contact forces in a three-dimensional space among various irregularly shaped bodies, e.g. the floater and the ice floes. Previously, various physics engines were successfully applied to simulate floaters in ice. However, limited attention was paid to the criteria for selecting a particular engine for the simulation of a floater in broken-ice conditions. In this paper, four publicly available physics engines (AgX Multiphysics, Open Dynamics Engine, PhysX and Vortex) are compared in terms of integration performance and contact detection accuracy. These two aspects are assumed to be the most important for simulating a floater in broken ice. Furthermore, the access to code, documentation quality and the level of technical support are evaluated and discussed. The main conclusion is that each physics engine has its own strength and weaknesses and none of the engines is perfect. These strength and weaknesses are revealed and discussed in the paper.}, keywords = {External}, pubstate = {published}, tppubtype = {inproceedings} } Numerical simulation of a floater in ice-infested waters can be performed using a physics engine. This software can dynamically detect contacts and calculate the contact forces in a three-dimensional space among various irregularly shaped bodies, e.g. the floater and the ice floes. Previously, various physics engines were successfully applied to simulate floaters in ice. However, limited attention was paid to the criteria for selecting a particular engine for the simulation of a floater in broken-ice conditions. In this paper, four publicly available physics engines (AgX Multiphysics, Open Dynamics Engine, PhysX and Vortex) are compared in terms of integration performance and contact detection accuracy. These two aspects are assumed to be the most important for simulating a floater in broken ice. Furthermore, the access to code, documentation quality and the level of technical support are evaluated and discussed. The main conclusion is that each physics engine has its own strength and weaknesses and none of the engines is perfect. These strength and weaknesses are revealed and discussed in the paper. | |
2011 |
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![]() | Wan, Yijun: Discrete element method in granular material simulations. 2011. (Type: Masters Thesis | Abstract | Links | BibTeX | Tags: External) @mastersthesis{wan2011discrete, title = {Discrete element method in granular material simulations}, author = {Yijun Wan}, url = {https://pure.tue.nl/ws/portalfiles/portal/47015912/716753-1.pdf}, year = {2011}, date = {2011-01-01}, journal = {Institute of Fraunhofer ITWM Kaiserslautern/Technical University of Kaiserslautern}, abstract = {This thesis describes the theories and simulations of granular material using discrete element method. With wide applications in agriculture and mechanical engineering, granular material exhibits a number of unique physical properties. The understanding of such properties is important in order to evaluate the performance of existing methodologies and to trigger the development of new models for different functionalities in the future. As a microscopic approach, discrete element method has been proved to be adequate in most simulations of granular material. An elaborated description is provided to illustrate a three-phase scheme from the fundamental discrete element model, which includes contact detection, force interaction and time integration. Additional to the conventional scheme, we present a bonding model with a connecting rod between each pair of contacted particles. Two enhanced bonding models are discussed in detail, with special characteristics in accordance with brittle and crack propagation features, respectively. On the contrary, continuum mechanical models give a macroscopic view to investigate granular material behaviors. Difficulties arise from the solving of a complex system of partial differential equations and the connections between model parameters and phenomenological ones. Moreover, triaxial test, uniaxial compression test and blade test are chosen as three representative experiments in granular material study. Simulation results implementing discrete element method are analyzed and discussed regarding the role of different parameters. By carefully choosing models and adjusting parameters, simulation results can have a good quantitative agreement with laboratory measurements. One of our kernel concerns is the computational complexity. Therefore, we focus on exploring effective simplified models with fewer variables.}, keywords = {External}, pubstate = {published}, tppubtype = {mastersthesis} } This thesis describes the theories and simulations of granular material using discrete element method. With wide applications in agriculture and mechanical engineering, granular material exhibits a number of unique physical properties. The understanding of such properties is important in order to evaluate the performance of existing methodologies and to trigger the development of new models for different functionalities in the future. As a microscopic approach, discrete element method has been proved to be adequate in most simulations of granular material. An elaborated description is provided to illustrate a three-phase scheme from the fundamental discrete element model, which includes contact detection, force interaction and time integration. Additional to the conventional scheme, we present a bonding model with a connecting rod between each pair of contacted particles. Two enhanced bonding models are discussed in detail, with special characteristics in accordance with brittle and crack propagation features, respectively. On the contrary, continuum mechanical models give a macroscopic view to investigate granular material behaviors. Difficulties arise from the solving of a complex system of partial differential equations and the connections between model parameters and phenomenological ones. Moreover, triaxial test, uniaxial compression test and blade test are chosen as three representative experiments in granular material study. Simulation results implementing discrete element method are analyzed and discussed regarding the role of different parameters. By carefully choosing models and adjusting parameters, simulation results can have a good quantitative agreement with laboratory measurements. One of our kernel concerns is the computational complexity. Therefore, we focus on exploring effective simplified models with fewer variables. |