The Experts below are selected from a list of 147 Experts worldwide ranked by ideXlab platform

Joel W. Burdick - One of the best experts on this subject based on the ideXlab platform.

  • IROS - Motion planning and control for a Tethered, rimless wheel differential drive vehicle
    2013 IEEE RSJ International Conference on Intelligent Robots and Systems, 2013
    Co-Authors: Krishna Shankar, Joel W. Burdick
    Abstract:

    This paper considers motion planning and control problems that are motivated by the design of Tethered, extreme terrain robots. We abstract the mobility structure of these systems using a Tethered differential drive robot with rimless wheels. We analyze several important issues related to this geometry. First it is shown that this vehicle cannot be modeled deterministically unless an additional degree of freedom relative to the standard differential drive vehicle is provided. The simplest kinematically consistent model is one that allows for slight prismatic motion of the axle, approximating the effects of wheel slip. We show that under mild assumptions, such a vehicle's reachable set is dense in SE(2), implying local maneuverability. Next we study some of the constraints which the Tether places on the vehicle's motions and derive scaling laws relating wheel and vehicle speeds. Using these results, we provide simple planning and approximate path-following methods that allow Tether Management. In particular, we consider trajectories produced by solving an optimal control problem to minimize the integral of absolute Tether-reeling rate.

  • Motion planning and control for a Tethered, rimless wheel differential drive vehicle
    2013 IEEE RSJ International Conference on Intelligent Robots and Systems, 2013
    Co-Authors: Krishna Shankar, Joel W. Burdick
    Abstract:

    This paper considers motion planning and control problems that are motivated by the design of Tethered, extreme terrain robots. We abstract the mobility structure of these systems using a Tethered differential drive robot with rimless wheels. We analyze several important issues related to this geometry. First it is shown that this vehicle cannot be modeled deterministically unless an additional degree of freedom relative to the standard differential drive vehicle is provided. The simplest kinematically consistent model is one that allows for slight prismatic motion of the axle, approximating the effects of wheel slip. We show that under mild assumptions, such a vehicle's reachable set is dense in SE(2), implying local maneuverability. Next we study some of the constraints which the Tether places on the vehicle's motions and derive scaling laws relating wheel and vehicle speeds. Using these results, we provide simple planning and approximate path-following methods that allow Tether Management. In particular, we consider trajectories produced by solving an optimal control problem to minimize the integral of absolute Tether-reeling rate.

Krishna Shankar - One of the best experts on this subject based on the ideXlab platform.

  • IROS - Motion planning and control for a Tethered, rimless wheel differential drive vehicle
    2013 IEEE RSJ International Conference on Intelligent Robots and Systems, 2013
    Co-Authors: Krishna Shankar, Joel W. Burdick
    Abstract:

    This paper considers motion planning and control problems that are motivated by the design of Tethered, extreme terrain robots. We abstract the mobility structure of these systems using a Tethered differential drive robot with rimless wheels. We analyze several important issues related to this geometry. First it is shown that this vehicle cannot be modeled deterministically unless an additional degree of freedom relative to the standard differential drive vehicle is provided. The simplest kinematically consistent model is one that allows for slight prismatic motion of the axle, approximating the effects of wheel slip. We show that under mild assumptions, such a vehicle's reachable set is dense in SE(2), implying local maneuverability. Next we study some of the constraints which the Tether places on the vehicle's motions and derive scaling laws relating wheel and vehicle speeds. Using these results, we provide simple planning and approximate path-following methods that allow Tether Management. In particular, we consider trajectories produced by solving an optimal control problem to minimize the integral of absolute Tether-reeling rate.

  • Motion planning and control for a Tethered, rimless wheel differential drive vehicle
    2013 IEEE RSJ International Conference on Intelligent Robots and Systems, 2013
    Co-Authors: Krishna Shankar, Joel W. Burdick
    Abstract:

    This paper considers motion planning and control problems that are motivated by the design of Tethered, extreme terrain robots. We abstract the mobility structure of these systems using a Tethered differential drive robot with rimless wheels. We analyze several important issues related to this geometry. First it is shown that this vehicle cannot be modeled deterministically unless an additional degree of freedom relative to the standard differential drive vehicle is provided. The simplest kinematically consistent model is one that allows for slight prismatic motion of the axle, approximating the effects of wheel slip. We show that under mild assumptions, such a vehicle's reachable set is dense in SE(2), implying local maneuverability. Next we study some of the constraints which the Tether places on the vehicle's motions and derive scaling laws relating wheel and vehicle speeds. Using these results, we provide simple planning and approximate path-following methods that allow Tether Management. In particular, we consider trajectories produced by solving an optimal control problem to minimize the integral of absolute Tether-reeling rate.

Nikola Georgiev - One of the best experts on this subject based on the ideXlab platform.

  • IROS - Series Elastic Tether Management for Rappelling Rovers
    2018 IEEE RSJ International Conference on Intelligent Robots and Systems (IROS), 2018
    Co-Authors: Travis Brown, Alessandro Stefanini, Jacek Sawoniewicz, Issa Nesnas, Nikola Georgiev
    Abstract:

    The Axel rappelling rover was designed to enable access to intriguing and important science sites that lie in difficult terrains that are inaccessible to conventional rovers. Extended autonomous rappelling calls for careful control of Tether tension, precise Management of Tether spooling, and some measure of shock tolerance. This paper covers the design and testing of a first-generation Tether Management system (TMS) for Axel. The system uses a double bull-wheel capstan driven by a low-stiffness series elastic actuator (SEA) to provide tension control and decouple internal spooling tension from external Tether tension. A series elastic actuator was chosen for this application to permit closed-loop Tether tension control and to provide shock/drop tolerance of the rappelling system both while moving and when the system is inactive with the motors locked. Experiments on the new TMS show that this design performs well in keeping nearly constant spooling tension while rejecting large dynamic disturbances at the output. While the SEA is very effective at maintaining a given tension contribution, the additional effects of friction and the unique mechanical properties of the Tether result in substantial errors in the measured output tension. Upcoming field trials will be used to evaluate the effectiveness and sufficiency of this system when integrated in Axel.

  • Series Elastic Tether Management for Rappelling Rovers
    2018 IEEE RSJ International Conference on Intelligent Robots and Systems (IROS), 2018
    Co-Authors: Travis Brown, Alessandro Stefanini, Jacek Sawoniewicz, Issa Nesnas, Nikola Georgiev
    Abstract:

    The Axel rappelling rover was designed to enable access to intriguing and important science sites that lie in difficult terrains that are inaccessible to conventional rovers. Extended autonomous rappelling calls for careful control of Tether tension, precise Management of Tether spooling, and some measure of shock tolerance. This paper covers the design and testing of a first-generation Tether Management system (TMS) for Axel. The system uses a double bull-wheel capstan driven by a low-stiffness series elastic actuator (SEA) to provide tension control and decouple internal spooling tension from external Tether tension. A series elastic actuator was chosen for this application to permit closed-loop Tether tension control and to provide shock/drop tolerance of the rappelling system both while moving and when the system is inactive with the motors locked. Experiments on the new TMS show that this design performs well in keeping nearly constant spooling tension while rejecting large dynamic disturbances at the output. While the SEA is very effective at maintaining a given tension contribution, the additional effects of friction and the unique mechanical properties of the Tether result in substantial errors in the measured output tension. Upcoming field trials will be used to evaluate the effectiveness and sufficiency of this system when integrated in Axel.

Travis Brown - One of the best experts on this subject based on the ideXlab platform.

  • IROS - Series Elastic Tether Management for Rappelling Rovers
    2018 IEEE RSJ International Conference on Intelligent Robots and Systems (IROS), 2018
    Co-Authors: Travis Brown, Alessandro Stefanini, Jacek Sawoniewicz, Issa Nesnas, Nikola Georgiev
    Abstract:

    The Axel rappelling rover was designed to enable access to intriguing and important science sites that lie in difficult terrains that are inaccessible to conventional rovers. Extended autonomous rappelling calls for careful control of Tether tension, precise Management of Tether spooling, and some measure of shock tolerance. This paper covers the design and testing of a first-generation Tether Management system (TMS) for Axel. The system uses a double bull-wheel capstan driven by a low-stiffness series elastic actuator (SEA) to provide tension control and decouple internal spooling tension from external Tether tension. A series elastic actuator was chosen for this application to permit closed-loop Tether tension control and to provide shock/drop tolerance of the rappelling system both while moving and when the system is inactive with the motors locked. Experiments on the new TMS show that this design performs well in keeping nearly constant spooling tension while rejecting large dynamic disturbances at the output. While the SEA is very effective at maintaining a given tension contribution, the additional effects of friction and the unique mechanical properties of the Tether result in substantial errors in the measured output tension. Upcoming field trials will be used to evaluate the effectiveness and sufficiency of this system when integrated in Axel.

  • Series Elastic Tether Management for Rappelling Rovers
    2018 IEEE RSJ International Conference on Intelligent Robots and Systems (IROS), 2018
    Co-Authors: Travis Brown, Alessandro Stefanini, Jacek Sawoniewicz, Issa Nesnas, Nikola Georgiev
    Abstract:

    The Axel rappelling rover was designed to enable access to intriguing and important science sites that lie in difficult terrains that are inaccessible to conventional rovers. Extended autonomous rappelling calls for careful control of Tether tension, precise Management of Tether spooling, and some measure of shock tolerance. This paper covers the design and testing of a first-generation Tether Management system (TMS) for Axel. The system uses a double bull-wheel capstan driven by a low-stiffness series elastic actuator (SEA) to provide tension control and decouple internal spooling tension from external Tether tension. A series elastic actuator was chosen for this application to permit closed-loop Tether tension control and to provide shock/drop tolerance of the rappelling system both while moving and when the system is inactive with the motors locked. Experiments on the new TMS show that this design performs well in keeping nearly constant spooling tension while rejecting large dynamic disturbances at the output. While the SEA is very effective at maintaining a given tension contribution, the additional effects of friction and the unique mechanical properties of the Tether result in substantial errors in the measured output tension. Upcoming field trials will be used to evaluate the effectiveness and sufficiency of this system when integrated in Axel.

Alessandro Stefanini - One of the best experts on this subject based on the ideXlab platform.

  • IROS - Series Elastic Tether Management for Rappelling Rovers
    2018 IEEE RSJ International Conference on Intelligent Robots and Systems (IROS), 2018
    Co-Authors: Travis Brown, Alessandro Stefanini, Jacek Sawoniewicz, Issa Nesnas, Nikola Georgiev
    Abstract:

    The Axel rappelling rover was designed to enable access to intriguing and important science sites that lie in difficult terrains that are inaccessible to conventional rovers. Extended autonomous rappelling calls for careful control of Tether tension, precise Management of Tether spooling, and some measure of shock tolerance. This paper covers the design and testing of a first-generation Tether Management system (TMS) for Axel. The system uses a double bull-wheel capstan driven by a low-stiffness series elastic actuator (SEA) to provide tension control and decouple internal spooling tension from external Tether tension. A series elastic actuator was chosen for this application to permit closed-loop Tether tension control and to provide shock/drop tolerance of the rappelling system both while moving and when the system is inactive with the motors locked. Experiments on the new TMS show that this design performs well in keeping nearly constant spooling tension while rejecting large dynamic disturbances at the output. While the SEA is very effective at maintaining a given tension contribution, the additional effects of friction and the unique mechanical properties of the Tether result in substantial errors in the measured output tension. Upcoming field trials will be used to evaluate the effectiveness and sufficiency of this system when integrated in Axel.

  • Tether Management and tension control for rappelling rovers
    2018
    Co-Authors: Alessandro Stefanini
    Abstract:

    Extreme Terrain Robotics Mobility: the work focuses on designing, building and testing a Tether Management system for JPL's Axel rover.

  • Series Elastic Tether Management for Rappelling Rovers
    2018 IEEE RSJ International Conference on Intelligent Robots and Systems (IROS), 2018
    Co-Authors: Travis Brown, Alessandro Stefanini, Jacek Sawoniewicz, Issa Nesnas, Nikola Georgiev
    Abstract:

    The Axel rappelling rover was designed to enable access to intriguing and important science sites that lie in difficult terrains that are inaccessible to conventional rovers. Extended autonomous rappelling calls for careful control of Tether tension, precise Management of Tether spooling, and some measure of shock tolerance. This paper covers the design and testing of a first-generation Tether Management system (TMS) for Axel. The system uses a double bull-wheel capstan driven by a low-stiffness series elastic actuator (SEA) to provide tension control and decouple internal spooling tension from external Tether tension. A series elastic actuator was chosen for this application to permit closed-loop Tether tension control and to provide shock/drop tolerance of the rappelling system both while moving and when the system is inactive with the motors locked. Experiments on the new TMS show that this design performs well in keeping nearly constant spooling tension while rejecting large dynamic disturbances at the output. While the SEA is very effective at maintaining a given tension contribution, the additional effects of friction and the unique mechanical properties of the Tether result in substantial errors in the measured output tension. Upcoming field trials will be used to evaluate the effectiveness and sufficiency of this system when integrated in Axel.