Pub Date : 2013-05-06DOI: 10.1109/ICRA.2013.6631173
Nikolay A. Atanasov, Bharathwaj Sankaran, J. L. Ny, Thomas Koletschka, George J. Pappas, Kostas Daniilidis
One of the central problems in computer vision is the detection of semantically important objects and the estimation of their pose. Most of the work in object detection has been based on single image processing and its performance is limited by occlusions and ambiguity in appearance and geometry. This paper proposes an active approach to object detection by controlling the point of view of a mobile depth camera. When an initial static detection phase identifies an object of interest, several hypotheses are made about its class and orientation. The sensor then plans a sequence of viewpoints, which balances the amount of energy used to move with the chance of identifying the correct hypothesis. We formulate an active M-ary hypothesis testing problem, which includes sensor mobility, and solve it using a point-based approximate POMDP algorithm. The validity of our approach is verified through simulation and experiments with real scenes captured by a kinect sensor. The results suggest a significant improvement over static object detection.
{"title":"Hypothesis testing framework for active object detection","authors":"Nikolay A. Atanasov, Bharathwaj Sankaran, J. L. Ny, Thomas Koletschka, George J. Pappas, Kostas Daniilidis","doi":"10.1109/ICRA.2013.6631173","DOIUrl":"https://doi.org/10.1109/ICRA.2013.6631173","url":null,"abstract":"One of the central problems in computer vision is the detection of semantically important objects and the estimation of their pose. Most of the work in object detection has been based on single image processing and its performance is limited by occlusions and ambiguity in appearance and geometry. This paper proposes an active approach to object detection by controlling the point of view of a mobile depth camera. When an initial static detection phase identifies an object of interest, several hypotheses are made about its class and orientation. The sensor then plans a sequence of viewpoints, which balances the amount of energy used to move with the chance of identifying the correct hypothesis. We formulate an active M-ary hypothesis testing problem, which includes sensor mobility, and solve it using a point-based approximate POMDP algorithm. The validity of our approach is verified through simulation and experiments with real scenes captured by a kinect sensor. The results suggest a significant improvement over static object detection.","PeriodicalId":259746,"journal":{"name":"2013 IEEE International Conference on Robotics and Automation","volume":"71 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114289535","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2013-05-06DOI: 10.1109/ICRA.2013.6631337
Y. Mengüç, Yong‐Lae Park, E. Martinez-Villalpando, P. Aubin, Miriam Zisook, L. Stirling, R. Wood, C. Walsh
Motion sensing has played an important role in the study of human biomechanics as well as the entertainment industry. Although existing technologies, such as optical or inertial based motion capture systems, have relatively high accuracy in detecting body motions, they still have inherent limitations with regards to mobility and wearability. In this paper, we present a soft motion sensing suit for measuring lower extremity joint motion. The sensing suit prototype includes a pair of elastic tights and three hyperelastic strain sensors. The strain sensors are made of silicone elastomer with embedded microchannels filled with conductive liquid. To form a sensing suit, these sensors are attached at the hip, knee, and ankle areas to measure the joint angles in the sagittal plane. The prototype motion sensing suit has significant potential as an autonomous system that can be worn by individuals during many activities outside the laboratory, from running to rock climbing. In this study we characterize the hyperelastic sensors in isolation to determine their mechanical and electrical responses to strain, and then demonstrate the sensing capability of the integrated suit in comparison with a ground truth optical motion capture system. Using simple calibration techniques, we can accurately track joint angles and gait phase. Our efforts result in a calculated trade off: with a maximum error less than 8%, the sensing suit does not track joints as accurately as optical motion capture, but its wearability means that it is not constrained to use only in a lab.
{"title":"Soft wearable motion sensing suit for lower limb biomechanics measurements","authors":"Y. Mengüç, Yong‐Lae Park, E. Martinez-Villalpando, P. Aubin, Miriam Zisook, L. Stirling, R. Wood, C. Walsh","doi":"10.1109/ICRA.2013.6631337","DOIUrl":"https://doi.org/10.1109/ICRA.2013.6631337","url":null,"abstract":"Motion sensing has played an important role in the study of human biomechanics as well as the entertainment industry. Although existing technologies, such as optical or inertial based motion capture systems, have relatively high accuracy in detecting body motions, they still have inherent limitations with regards to mobility and wearability. In this paper, we present a soft motion sensing suit for measuring lower extremity joint motion. The sensing suit prototype includes a pair of elastic tights and three hyperelastic strain sensors. The strain sensors are made of silicone elastomer with embedded microchannels filled with conductive liquid. To form a sensing suit, these sensors are attached at the hip, knee, and ankle areas to measure the joint angles in the sagittal plane. The prototype motion sensing suit has significant potential as an autonomous system that can be worn by individuals during many activities outside the laboratory, from running to rock climbing. In this study we characterize the hyperelastic sensors in isolation to determine their mechanical and electrical responses to strain, and then demonstrate the sensing capability of the integrated suit in comparison with a ground truth optical motion capture system. Using simple calibration techniques, we can accurately track joint angles and gait phase. Our efforts result in a calculated trade off: with a maximum error less than 8%, the sensing suit does not track joints as accurately as optical motion capture, but its wearability means that it is not constrained to use only in a lab.","PeriodicalId":259746,"journal":{"name":"2013 IEEE International Conference on Robotics and Automation","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114459938","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2013-05-06DOI: 10.1109/ICRA.2013.6631099
A. Holladay, Jennifer L. Barry, L. Kaelbling, Tomas Lozano-Perez
We present an approach to robust placing that uses movable surfaces in the environment to guide a poorly grasped object into a goal pose. This problem is an instance of the inverse motion planning problem, in which we solve for a configuration of the environment that makes desired trajectories likely. To calculate the probability that an object will take a particular trajectory, we model the physics of placing as a mixture model of simple object motions. Our algorithm searches over the possible configurations of the object and environment and uses this model to choose the configuration most likely to lead to a successful place. We show that this algorithm allows the PR2 robot to execute placements that fail with traditional placing implementations.
{"title":"Object placement as inverse motion planning","authors":"A. Holladay, Jennifer L. Barry, L. Kaelbling, Tomas Lozano-Perez","doi":"10.1109/ICRA.2013.6631099","DOIUrl":"https://doi.org/10.1109/ICRA.2013.6631099","url":null,"abstract":"We present an approach to robust placing that uses movable surfaces in the environment to guide a poorly grasped object into a goal pose. This problem is an instance of the inverse motion planning problem, in which we solve for a configuration of the environment that makes desired trajectories likely. To calculate the probability that an object will take a particular trajectory, we model the physics of placing as a mixture model of simple object motions. Our algorithm searches over the possible configurations of the object and environment and uses this model to choose the configuration most likely to lead to a successful place. We show that this algorithm allows the PR2 robot to execute placements that fail with traditional placing implementations.","PeriodicalId":259746,"journal":{"name":"2013 IEEE International Conference on Robotics and Automation","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114569702","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2013-05-06DOI: 10.1109/ICRA.2013.6631010
Hongkai Dai, Russ Tedrake
In this paper we seek to quantify and explicitly optimize the robustness of a control system for a robot walking on terrain with uncertain geometry. Geometric perturbations to the terrain enter the equations of motion through a relocation of the hybrid event “guards” which trigger an impact event; these perturbations can have a large effect on the stability of the robot and do not fit into the traditional robust control analysis and design methodologies without additional machinery. We attempt to provide that machinery here. In particular, we quantify the robustness of the system to terrain perturbations by defining an L2 gain from terrain perturbations to deviations from the nominal limit cycle. We show that the solution to a periodic dissipation inequality provides a sufficient upper bound on this gain for a linear approximation of the dynamics around the limit cycle, and we formulate a semidefinite programming problem to compute the L2 gain for the system with a fixed linear controller. We then use either binary search or an iterative optimization method to construct a linear robust controller and to minimize the L2 gain. The simulation results on canonical robots suggest that the L2 gain is closely correlated to the actual number of steps traversed on the rough terrain, and our controller can improve the robot's robustness to terrain disturbances.
{"title":"L2-gain optimization for robust bipedal walking on unknown terrain","authors":"Hongkai Dai, Russ Tedrake","doi":"10.1109/ICRA.2013.6631010","DOIUrl":"https://doi.org/10.1109/ICRA.2013.6631010","url":null,"abstract":"In this paper we seek to quantify and explicitly optimize the robustness of a control system for a robot walking on terrain with uncertain geometry. Geometric perturbations to the terrain enter the equations of motion through a relocation of the hybrid event “guards” which trigger an impact event; these perturbations can have a large effect on the stability of the robot and do not fit into the traditional robust control analysis and design methodologies without additional machinery. We attempt to provide that machinery here. In particular, we quantify the robustness of the system to terrain perturbations by defining an L2 gain from terrain perturbations to deviations from the nominal limit cycle. We show that the solution to a periodic dissipation inequality provides a sufficient upper bound on this gain for a linear approximation of the dynamics around the limit cycle, and we formulate a semidefinite programming problem to compute the L2 gain for the system with a fixed linear controller. We then use either binary search or an iterative optimization method to construct a linear robust controller and to minimize the L2 gain. The simulation results on canonical robots suggest that the L2 gain is closely correlated to the actual number of steps traversed on the rough terrain, and our controller can improve the robot's robustness to terrain disturbances.","PeriodicalId":259746,"journal":{"name":"2013 IEEE International Conference on Robotics and Automation","volume":"59 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116617115","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2013-05-06DOI: 10.1109/ICRA.2013.6631148
Eduardo Arvelo, Eric J. Kim, N. C. Martins
This paper presents a method for the design of time-invariant memoryless control policies for robots tasked with persistent surveillance of an area in which there are forbidden regions. We model each robot as a controlled Markov chain whose state comprises its position on a finite two-dimensional lattice and the direction of motion. The goal is to find the minimum number of robots and an associated time-invariant memoryless control policy that guarantees that the largest number of states are persistently surveilled without ever visiting a forbidden state. We propose a design method that relies on a finitely parametrized convex program inspired by entropy maximization principles. For clarity of exposition, we focus on simple dynamics and state/control spaces, however the proposed methodology can be extended to more general cases. Numerical examples are provided.
{"title":"Maximal persistent surveillance under safety constraints","authors":"Eduardo Arvelo, Eric J. Kim, N. C. Martins","doi":"10.1109/ICRA.2013.6631148","DOIUrl":"https://doi.org/10.1109/ICRA.2013.6631148","url":null,"abstract":"This paper presents a method for the design of time-invariant memoryless control policies for robots tasked with persistent surveillance of an area in which there are forbidden regions. We model each robot as a controlled Markov chain whose state comprises its position on a finite two-dimensional lattice and the direction of motion. The goal is to find the minimum number of robots and an associated time-invariant memoryless control policy that guarantees that the largest number of states are persistently surveilled without ever visiting a forbidden state. We propose a design method that relies on a finitely parametrized convex program inspired by entropy maximization principles. For clarity of exposition, we focus on simple dynamics and state/control spaces, however the proposed methodology can be extended to more general cases. Numerical examples are provided.","PeriodicalId":259746,"journal":{"name":"2013 IEEE International Conference on Robotics and Automation","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116813931","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2013-05-06DOI: 10.1109/ICRA.2013.6631037
Nicholas J. Kohut, Andrew O. Pullin, D. Haldane, David Zarrouk, R. Fearing
For maximum maneuverability, terrestrial robots need to be able to turn precisely, quickly, and with a small radius. Previous efforts at turning in legged robots primarily have used leg force or velocity modulation. We developed a palm-sized legged robot, called TAYLRoACH. The tailed robot was able to make rapid, precise turns using only the actuation of a tail appendage. By rapidly rotating the tail as the robot runs forward, the robot was able to make sudden 90° turns at 360 °s-1. Unlike other robots, this is done with almost no change in its running speed. We have also modeled the dynamics of this maneuver, to examine how features, such as tail length and mass, affect the robot's turning ability. This approach has produced turns with a radius of 0.4 body lengths at 3.2 body lengths per second running speed. Using gyro feedback and bang-bang control, we achieve an accuracy of ± 5° for a 60° turn.
{"title":"Precise dynamic turning of a 10 cm legged robot on a low friction surface using a tail","authors":"Nicholas J. Kohut, Andrew O. Pullin, D. Haldane, David Zarrouk, R. Fearing","doi":"10.1109/ICRA.2013.6631037","DOIUrl":"https://doi.org/10.1109/ICRA.2013.6631037","url":null,"abstract":"For maximum maneuverability, terrestrial robots need to be able to turn precisely, quickly, and with a small radius. Previous efforts at turning in legged robots primarily have used leg force or velocity modulation. We developed a palm-sized legged robot, called TAYLRoACH. The tailed robot was able to make rapid, precise turns using only the actuation of a tail appendage. By rapidly rotating the tail as the robot runs forward, the robot was able to make sudden 90° turns at 360 °s-1. Unlike other robots, this is done with almost no change in its running speed. We have also modeled the dynamics of this maneuver, to examine how features, such as tail length and mass, affect the robot's turning ability. This approach has produced turns with a radius of 0.4 body lengths at 3.2 body lengths per second running speed. Using gyro feedback and bang-bang control, we achieve an accuracy of ± 5° for a 60° turn.","PeriodicalId":259746,"journal":{"name":"2013 IEEE International Conference on Robotics and Automation","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128445611","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2013-05-06DOI: 10.1109/ICRA.2013.6631053
Daniel Souto, A. Faíña, F. López-Peña, R. Duro
This paper is concerned with the design and implementation of a new concept of robot to clean the underwater sections of ship hulls without using any magnetic attachment. The use of this type of robots on a regular basis to preserve a clean hull, usually when ships are in port or anchored, will improve the efficiency of the ships and will permit a reduction in the use of chemicals that are harmful to the environment to prevent the growth of marine life on the hull. The main contribution of the robot described in this paper is that it is a completely novel design that through an appropriate morphology solves the problems that arise when moving along hulls, including changing planes, negotiating appendices, portholes, corners, and other elements. It thus provides a basis for completely autonomous operation. The design and implementation of the robot is described and some simulations and tests in real environments are presented.
{"title":"Lappa: A new type of robot for underwater non-magnetic and complex hull cleaning","authors":"Daniel Souto, A. Faíña, F. López-Peña, R. Duro","doi":"10.1109/ICRA.2013.6631053","DOIUrl":"https://doi.org/10.1109/ICRA.2013.6631053","url":null,"abstract":"This paper is concerned with the design and implementation of a new concept of robot to clean the underwater sections of ship hulls without using any magnetic attachment. The use of this type of robots on a regular basis to preserve a clean hull, usually when ships are in port or anchored, will improve the efficiency of the ships and will permit a reduction in the use of chemicals that are harmful to the environment to prevent the growth of marine life on the hull. The main contribution of the robot described in this paper is that it is a completely novel design that through an appropriate morphology solves the problems that arise when moving along hulls, including changing planes, negotiating appendices, portholes, corners, and other elements. It thus provides a basis for completely autonomous operation. The design and implementation of the robot is described and some simulations and tests in real environments are presented.","PeriodicalId":259746,"journal":{"name":"2013 IEEE International Conference on Robotics and Automation","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128268653","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2013-05-06DOI: 10.1109/ICRA.2013.6630701
Lonnie T. Parker, R. A. Coogle, A. Howard
Environmental monitoring of spatially-distributed geo-physical processes (e.g., temperature, pressure, or humidity) requires efficient sampling schemes, particularly, when employing an autonomous mobile agent to execute the sampling task. Many approaches have considered optimal sampling strategies which specialize in minimizing estimation error, while others emphasize reducing resource usage, yet rarely are both of these performance parameters used concurrently to influence the navigation. This work discusses how a spatial estimation process and resource awareness are integrated to generate an informed navigation policy for collecting useful measurement information. We also enable a direct comparison between this informed navigation method and more common approaches using two performance metrics. We show that our informed navigation outperforms these approaches based on performance evaluation as a function of estimation error and resource usage for a useful range of coverage within the sampling area.
{"title":"Estimation-informed, resource-aware robot navigation for environmental monitoring applications","authors":"Lonnie T. Parker, R. A. Coogle, A. Howard","doi":"10.1109/ICRA.2013.6630701","DOIUrl":"https://doi.org/10.1109/ICRA.2013.6630701","url":null,"abstract":"Environmental monitoring of spatially-distributed geo-physical processes (e.g., temperature, pressure, or humidity) requires efficient sampling schemes, particularly, when employing an autonomous mobile agent to execute the sampling task. Many approaches have considered optimal sampling strategies which specialize in minimizing estimation error, while others emphasize reducing resource usage, yet rarely are both of these performance parameters used concurrently to influence the navigation. This work discusses how a spatial estimation process and resource awareness are integrated to generate an informed navigation policy for collecting useful measurement information. We also enable a direct comparison between this informed navigation method and more common approaches using two performance metrics. We show that our informed navigation outperforms these approaches based on performance evaluation as a function of estimation error and resource usage for a useful range of coverage within the sampling area.","PeriodicalId":259746,"journal":{"name":"2013 IEEE International Conference on Robotics and Automation","volume":"84 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128567351","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2013-05-06DOI: 10.1109/ICRA.2013.6631417
A. Bajo, Ryan B. Pickens, S. Herrell, N. Simaan
Constrained motion control of robotic end-effectors is essential for safe operation in confined spaces such as the urinary bladder. This paper presents the clinical motivation for the development of new control algorithms for robotic-assisted transurethral bladder resection and surveillance using multisegment continuum robots. The anatomy, workspace, and access constraints for this procedure are identified and used as a guideline for the design of the telesurgical system and its control architecture. Constraints are mapped into the configuration space of the robot rather than in task space simplifying the modeling and the enforcement of virtual fixtures. The redundancy resolution is autonomously modified in order to exploit the remaining degrees of freedom using task priority. These methods are validated on a glass model of urinary bladder.
{"title":"Constrained motion control of multisegment continuum robots for transurethral bladder resection and surveillance","authors":"A. Bajo, Ryan B. Pickens, S. Herrell, N. Simaan","doi":"10.1109/ICRA.2013.6631417","DOIUrl":"https://doi.org/10.1109/ICRA.2013.6631417","url":null,"abstract":"Constrained motion control of robotic end-effectors is essential for safe operation in confined spaces such as the urinary bladder. This paper presents the clinical motivation for the development of new control algorithms for robotic-assisted transurethral bladder resection and surveillance using multisegment continuum robots. The anatomy, workspace, and access constraints for this procedure are identified and used as a guideline for the design of the telesurgical system and its control architecture. Constraints are mapped into the configuration space of the robot rather than in task space simplifying the modeling and the enforcement of virtual fixtures. The redundancy resolution is autonomously modified in order to exploit the remaining degrees of freedom using task priority. These methods are validated on a glass model of urinary bladder.","PeriodicalId":259746,"journal":{"name":"2013 IEEE International Conference on Robotics and Automation","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129255207","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2013-05-06DOI: 10.1109/ICRA.2013.6630901
C. Rossa, J. Lozada, A. Micaelli
This paper presents a stable control method for a hybrid haptic device comprising a brake and a motor. A review of stability condition via describing function analysis is first presented. The results show that while brakes are intrinsically stable, an active device is limited in terms of stiffness. The stability is however improved if the brake simulates a physical damping. Subsequently, the stability condition is obtained via passivity condition analysis. The results demonstrate that the stiffness is improved by engaging both actuators to create resistive forces and the passivity is respected assuming a passive virtual environment. An energy and a stiffness-bounding algorithms have been developed in order to assure the stability of the coupled system in this case. It has been tested and validated using a 1-DOF hybrid haptic device by the simulation of an unstable and an active virtual environments respectively . Experimental results show that the displayable stiffness is improved under stability conditions using the control method. Furthermore, it allows the hybrid system to simulate nonlinear and unstable virtual environments and the controller remains independent of the virtual environment model.
{"title":"Stable haptic interaction using passive and active actuators","authors":"C. Rossa, J. Lozada, A. Micaelli","doi":"10.1109/ICRA.2013.6630901","DOIUrl":"https://doi.org/10.1109/ICRA.2013.6630901","url":null,"abstract":"This paper presents a stable control method for a hybrid haptic device comprising a brake and a motor. A review of stability condition via describing function analysis is first presented. The results show that while brakes are intrinsically stable, an active device is limited in terms of stiffness. The stability is however improved if the brake simulates a physical damping. Subsequently, the stability condition is obtained via passivity condition analysis. The results demonstrate that the stiffness is improved by engaging both actuators to create resistive forces and the passivity is respected assuming a passive virtual environment. An energy and a stiffness-bounding algorithms have been developed in order to assure the stability of the coupled system in this case. It has been tested and validated using a 1-DOF hybrid haptic device by the simulation of an unstable and an active virtual environments respectively . Experimental results show that the displayable stiffness is improved under stability conditions using the control method. Furthermore, it allows the hybrid system to simulate nonlinear and unstable virtual environments and the controller remains independent of the virtual environment model.","PeriodicalId":259746,"journal":{"name":"2013 IEEE International Conference on Robotics and Automation","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129333236","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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