The Experts below are selected from a list of 243 Experts worldwide ranked by ideXlab platform

Toshimasa Miyazaki - One of the best experts on this subject based on the ideXlab platform.

  • Switching Controller-less Approach and Contact Controls Based on Force Impulse Regulator
    2020 IEEE ASME International Conference on Advanced Intelligent Mechatronics (AIM), 2020
    Co-Authors: Yusuke Kawai, Yuki Yokokura, Kiyoshi Ohishi, Toshimasa Miyazaki
    Abstract:

    This paper proposes an approach and contact controls based on the force impulse regulator. The force impulse regulator is constructed using two-spring resonant system using the motor-Side Velocity control and the force and position sensors integrated disturbance disturbance observer (FPIDO). Control gains are determined using pole placement method and the force impulse command is determined according to desired approach speed. The proposed approach is verified through the numerical simulation and experimental results.

  • Fine Torsion Torque Control for Geared Motors by a State-Reference-Dependent Variable-Order Friction Observer
    2020 IEEE 29th International Symposium on Industrial Electronics (ISIE), 2020
    Co-Authors: Juan Padron, Yusuke Kawai, Yuki Yokokura, Kiyoshi Ohishi, Toshimasa Miyazaki
    Abstract:

    Controlling torsion torque in geared motors is essential for precise control of load-Side dynamics. An I-P torsion torque controller (TTC) structure combined with a friction observer based on the disturbance observer has been previously proposed for this means. However, in motors with strong nonlinear friction, this method is not able to quickly compensate nonlinear friction when rotation direction changes, severely affecting the torsion torque control performance. This paper proposes a variable-order friction observer with a switching law based on the motor-Side Velocity (state) and torque command (reference) that is able to compensate for the effects of friction in the torsion torque response, while also preventing limit cycles due to the friction compensation itself. First, a review of the conventional I-P TTC with zero-order friction observer method is given. Followed by this we explain the decomposition process of a high-order friction observer into a variable-order form. Next, a stability analysis of the variable-order friction observer is done. Then, appropriate switching functions are designed to effectively compensate friction and prevent limit cycles. Finally, the effectiveness of the proposed method is proven by numerical simulation results and experimental results with a 1 DOF robotic arm.

  • Realization of Resonance Ratio Control Focusing on Duality of Torque and Velocity for Two-Inertia System with Environment
    2019 IEEE 28th International Symposium on Industrial Electronics (ISIE), 2019
    Co-Authors: Yusuke Kawai, Yuki Yokokura, Kiyoshi Ohishi, Toshimasa Miyazaki
    Abstract:

    Conventionally, the two-inertia system with environment has two resonant frequencies and one anti-resonant frequency. In the case of using resonance ratio control (RRC) for a two-inertia system with environment, it is difficult to determine the resonance ratio. Thus, this paper focuses on the duality between torque and Velocity, and a two-spring resonant system is constructed based on motor-Side Velocity control. In addition, RRC based on motor-Side Velocity control and load-Side Velocity observer (LVOB) is proposed, and the duality between the two-inertia resonant system and two-spring resonant system is demonstrated. Finally, load-Side torque control based on RRC is confirmed, and that the RRC is the same as conventional RRC. Compared with the RRC of two-inertia system and RRC of two-spring system, a duality is demonstrated, and the effectiveness of the proposed control method is verified through numerical simulation and experiment.

  • ISIE - Realization of Resonance Ratio Control Focusing on Duality of Torque and Velocity for Two-Inertia System with Environment
    2019 IEEE 28th International Symposium on Industrial Electronics (ISIE), 2019
    Co-Authors: Yusuke Kawai, Yuki Yokokura, Kiyoshi Ohishi, Toshimasa Miyazaki
    Abstract:

    Conventionally, the two-inertia system with environment has two resonant frequencies and one anti-resonant frequency. In the case of using resonance ratio control (RRC) for a two-inertia system with environment, it is difficult to determine the resonance ratio. Thus, this paper focuses on the duality between torque and Velocity, and a two-spring resonant system is constructed based on motor-Side Velocity control. In addition, RRC based on motor-Side Velocity control and load-Side Velocity observer (LVOB) is proposed, and the duality between the two-inertia resonant system and two-spring resonant system is demonstrated. Finally, load-Side torque control based on RRC is confirmed, and that the RRC is the same as conventional RRC. Compared with the RRC of two-inertia system and RRC of two-spring system, a duality is demonstrated, and the effectiveness of the proposed control method is verified through numerical simulation and experiment.

  • Analysis of Estimation Performance of Load-Side Torque and Load-Side Velocity Observers for Human Interaction Control Based on Torsion Torque Control
    2018 IEEE ASME International Conference on Advanced Intelligent Mechatronics (AIM), 2018
    Co-Authors: Yusuke Kawai, Yuki Yokokura, Kiyoshi Ohishi, Toshimasa Miyazaki
    Abstract:

    This paper proposes a back-forward drivable control based on torsion torque control (TTC) that achieves both back-forward drivability and vibration suppression for a two-inertia system. The proposed system combines the TTC that consists of I-P controller and Velocity deviation feedback and a motor-Side normalization compensator (MNC) to facilitate human-robot interactions. For the Velocity deviation estimation, load-Side torque observer (LTOB) and load-Side Velocity observer (LVOB) are evaluated on estimation performance. The better observer is applied to the TTC from the analysis results. The effectiveness of the proposed control system is verified by simulation and experimental results, and the vibration of the back-forward drivable response is conSiderably suppressed.

Enver Tatlicioglu - One of the best experts on this subject based on the ideXlab platform.

  • CDC - Nonlinear control of tendon driven robot manipulators: Elimination of actuator Side position measurements
    2015 54th IEEE Conference on Decision and Control (CDC), 2015
    Co-Authors: Beytullah Okur, Erkan Zergeroglu, Enver Tatlicioglu
    Abstract:

    In this study, a partial state feedback controller is proposed for the link position tracking control problem of flexible tendon driven robotic systems. Specifically; a nonlinear model based controller is formulated for tendon driven robot manipulators under the constraint that only the link position and tendon expansion force measurements are available. Despite the lack of link and actuator Side Velocity and actuator position measurements, the proposed controller ensures exponential link position tracking. To eliminate the need of actuator position and Velocity measurements, a model based Velocity observer has been utilized. Stability of the closed loop system and boundedness of system states are proven via Lyapunov based arguments. The performance of the purposed observer-controller couple is then verified by a set of numerical simulations.

  • Nonlinear control of tendon driven robot manipulators: Elimination of actuator Side position measurements
    2015 54th IEEE Conference on Decision and Control (CDC), 2015
    Co-Authors: Beytullah Okur, Erkan Zergeroglu, Enver Tatlicioglu
    Abstract:

    In this study, a partial state feedback controller is proposed for the link position tracking control problem of flexible tendon driven robotic systems. Specifically; a nonlinear model based controller is formulated for tendon driven robot manipulators under the constraint that only the link position and tendon expansion force measurements are available. Despite the lack of link and actuator Side Velocity and actuator position measurements, the proposed controller ensures exponential link position tracking. To eliminate the need of actuator position and Velocity measurements, a model based Velocity observer has been utilized. Stability of the closed loop system and boundedness of system states are proven via Lyapunov based arguments. The performance of the purposed observer-controller couple is then verified by a set of numerical simulations.

Alin Albu-schäffer - One of the best experts on this subject based on the ideXlab platform.

  • Optimal Control for Maximizing Link Velocity of Robotic Variable Stiffness Joints
    IFAC Proceedings Volumes, 2016
    Co-Authors: Sami Haddadin, Michael Weis, Sebastian Wolf, Alin Albu-schäffer
    Abstract:

    Abstract In this paper we evaluate the potential of Variable Stiffness Actuation to utilize its inherent joint elasticity and capability to adjust the intrinsic joint stiffness. These abilities make it possible to realize fundamentally different motion control schemes in comparison to intrinsically stiff robots. In this paper we treat the problem of how to generate optimally fast link Side Velocity at a certain time instant by fully exploiting the elastic energy transfer effects between motor, joint elasticity, stiffness adjustment mechanism, and link. Based on optimal control theory we show that it is possible to significantly and optimally exceed the motor maximum Velocity by appropriate motor commands. We solve the problem for models of increasing complexity in order to consecutively elaborate the core insights into the chosen problem. Finally, we present experimental results with a VIA joint prototype, confirming the correctness of the developed formalism.

  • IROS - On impact decoupling properties of elastic robots and time optimal Velocity maximization on joint level
    2012 IEEE RSJ International Conference on Intelligent Robots and Systems, 2012
    Co-Authors: Sami Haddadin, Nico Mansfeld, Kai Krieger, Alin Albu-schäffer
    Abstract:

    Designing intrinsically elastic robot systems, making systematic use of their properties in terms of impact decoupling, and exploiting temporary energy storage and release during excitative motions is becoming an important topic in nowadays robot design and control. In this paper we treat two distinct questions that are of primary interest in this context. First, we elaborate an accurate estimation of the maximum contact force during simplified human/obstacle-robot collisions and how the relation between reflected joint stiffness, link inertia, human/obstacle stiffness, and human/obstacle inertia affect it. Overall, our analysis provides a safety oriented methodology for designing intrinsically elastic joints and clearly defines how its basic mechanical properties influence the overall collision behavior. This can be used for designing safer and more robust robots. Secondly, we provide a closed form solution of reaching maximum link Side Velocity in minimum time with an intrinsically elastic joint, while keeping the maximum deflection constraint. This gives an analytical tool for determining suitable stiffness and maximum deflection values in order to be able to execute desired optimal excitation trajectories for explosive motions.

  • On impact decoupling properties of elastic robots and time optimal Velocity maximization on joint level
    IEEE International Conference on Intelligent Robots and Systems, 2012
    Co-Authors: Sami Haddadin, Nico Mansfeld, Kai Krieger, Alin Albu-schäffer
    Abstract:

    Designing intrinsically elastic robot systems, making systematic use of their properties in terms of impact decoupling, and exploiting temporary energy storage and release during excitative motions is becoming an important topic in nowadays robot design and control. In this paper we treat two distinct questions that are of primary interest in this context. First, we elaborate an accurate estimation of the maximum contact force during simplified human/obstacle-robot collisions and how the relation between reflected joint stiffness, link inertia, human/obstacle stiffness, and human/obstacle inertia affect it. Overall, our analysis provides a safety oriented methodology for designing intrinsically elastic joints and clearly defines how its basic mechanical properties influence the overall collision behavior. This can be used for designing safer and more robust robots. Secondly, we provide a closed form solution of reaching maximum link Side Velocity in minimum time with an intrinsically elastic joint, while keeping the maximum deflection constraint. This gives an analytical tool for determining suitable stiffness and maximum deflection values in order to be able to execute desired optimal excitation trajectories for explosive motions.

Yusuke Kawai - One of the best experts on this subject based on the ideXlab platform.

  • Switching Controller-less Approach and Contact Controls Based on Force Impulse Regulator
    2020 IEEE ASME International Conference on Advanced Intelligent Mechatronics (AIM), 2020
    Co-Authors: Yusuke Kawai, Yuki Yokokura, Kiyoshi Ohishi, Toshimasa Miyazaki
    Abstract:

    This paper proposes an approach and contact controls based on the force impulse regulator. The force impulse regulator is constructed using two-spring resonant system using the motor-Side Velocity control and the force and position sensors integrated disturbance disturbance observer (FPIDO). Control gains are determined using pole placement method and the force impulse command is determined according to desired approach speed. The proposed approach is verified through the numerical simulation and experimental results.

  • Fine Torsion Torque Control for Geared Motors by a State-Reference-Dependent Variable-Order Friction Observer
    2020 IEEE 29th International Symposium on Industrial Electronics (ISIE), 2020
    Co-Authors: Juan Padron, Yusuke Kawai, Yuki Yokokura, Kiyoshi Ohishi, Toshimasa Miyazaki
    Abstract:

    Controlling torsion torque in geared motors is essential for precise control of load-Side dynamics. An I-P torsion torque controller (TTC) structure combined with a friction observer based on the disturbance observer has been previously proposed for this means. However, in motors with strong nonlinear friction, this method is not able to quickly compensate nonlinear friction when rotation direction changes, severely affecting the torsion torque control performance. This paper proposes a variable-order friction observer with a switching law based on the motor-Side Velocity (state) and torque command (reference) that is able to compensate for the effects of friction in the torsion torque response, while also preventing limit cycles due to the friction compensation itself. First, a review of the conventional I-P TTC with zero-order friction observer method is given. Followed by this we explain the decomposition process of a high-order friction observer into a variable-order form. Next, a stability analysis of the variable-order friction observer is done. Then, appropriate switching functions are designed to effectively compensate friction and prevent limit cycles. Finally, the effectiveness of the proposed method is proven by numerical simulation results and experimental results with a 1 DOF robotic arm.

  • Realization of Resonance Ratio Control Focusing on Duality of Torque and Velocity for Two-Inertia System with Environment
    2019 IEEE 28th International Symposium on Industrial Electronics (ISIE), 2019
    Co-Authors: Yusuke Kawai, Yuki Yokokura, Kiyoshi Ohishi, Toshimasa Miyazaki
    Abstract:

    Conventionally, the two-inertia system with environment has two resonant frequencies and one anti-resonant frequency. In the case of using resonance ratio control (RRC) for a two-inertia system with environment, it is difficult to determine the resonance ratio. Thus, this paper focuses on the duality between torque and Velocity, and a two-spring resonant system is constructed based on motor-Side Velocity control. In addition, RRC based on motor-Side Velocity control and load-Side Velocity observer (LVOB) is proposed, and the duality between the two-inertia resonant system and two-spring resonant system is demonstrated. Finally, load-Side torque control based on RRC is confirmed, and that the RRC is the same as conventional RRC. Compared with the RRC of two-inertia system and RRC of two-spring system, a duality is demonstrated, and the effectiveness of the proposed control method is verified through numerical simulation and experiment.

  • ISIE - Realization of Resonance Ratio Control Focusing on Duality of Torque and Velocity for Two-Inertia System with Environment
    2019 IEEE 28th International Symposium on Industrial Electronics (ISIE), 2019
    Co-Authors: Yusuke Kawai, Yuki Yokokura, Kiyoshi Ohishi, Toshimasa Miyazaki
    Abstract:

    Conventionally, the two-inertia system with environment has two resonant frequencies and one anti-resonant frequency. In the case of using resonance ratio control (RRC) for a two-inertia system with environment, it is difficult to determine the resonance ratio. Thus, this paper focuses on the duality between torque and Velocity, and a two-spring resonant system is constructed based on motor-Side Velocity control. In addition, RRC based on motor-Side Velocity control and load-Side Velocity observer (LVOB) is proposed, and the duality between the two-inertia resonant system and two-spring resonant system is demonstrated. Finally, load-Side torque control based on RRC is confirmed, and that the RRC is the same as conventional RRC. Compared with the RRC of two-inertia system and RRC of two-spring system, a duality is demonstrated, and the effectiveness of the proposed control method is verified through numerical simulation and experiment.

  • Analysis of Estimation Performance of Load-Side Torque and Load-Side Velocity Observers for Human Interaction Control Based on Torsion Torque Control
    2018 IEEE ASME International Conference on Advanced Intelligent Mechatronics (AIM), 2018
    Co-Authors: Yusuke Kawai, Yuki Yokokura, Kiyoshi Ohishi, Toshimasa Miyazaki
    Abstract:

    This paper proposes a back-forward drivable control based on torsion torque control (TTC) that achieves both back-forward drivability and vibration suppression for a two-inertia system. The proposed system combines the TTC that consists of I-P controller and Velocity deviation feedback and a motor-Side normalization compensator (MNC) to facilitate human-robot interactions. For the Velocity deviation estimation, load-Side torque observer (LTOB) and load-Side Velocity observer (LVOB) are evaluated on estimation performance. The better observer is applied to the TTC from the analysis results. The effectiveness of the proposed control system is verified by simulation and experimental results, and the vibration of the back-forward drivable response is conSiderably suppressed.

Beytullah Okur - One of the best experts on this subject based on the ideXlab platform.

  • CDC - Nonlinear control of tendon driven robot manipulators: Elimination of actuator Side position measurements
    2015 54th IEEE Conference on Decision and Control (CDC), 2015
    Co-Authors: Beytullah Okur, Erkan Zergeroglu, Enver Tatlicioglu
    Abstract:

    In this study, a partial state feedback controller is proposed for the link position tracking control problem of flexible tendon driven robotic systems. Specifically; a nonlinear model based controller is formulated for tendon driven robot manipulators under the constraint that only the link position and tendon expansion force measurements are available. Despite the lack of link and actuator Side Velocity and actuator position measurements, the proposed controller ensures exponential link position tracking. To eliminate the need of actuator position and Velocity measurements, a model based Velocity observer has been utilized. Stability of the closed loop system and boundedness of system states are proven via Lyapunov based arguments. The performance of the purposed observer-controller couple is then verified by a set of numerical simulations.

  • Nonlinear control of tendon driven robot manipulators: Elimination of actuator Side position measurements
    2015 54th IEEE Conference on Decision and Control (CDC), 2015
    Co-Authors: Beytullah Okur, Erkan Zergeroglu, Enver Tatlicioglu
    Abstract:

    In this study, a partial state feedback controller is proposed for the link position tracking control problem of flexible tendon driven robotic systems. Specifically; a nonlinear model based controller is formulated for tendon driven robot manipulators under the constraint that only the link position and tendon expansion force measurements are available. Despite the lack of link and actuator Side Velocity and actuator position measurements, the proposed controller ensures exponential link position tracking. To eliminate the need of actuator position and Velocity measurements, a model based Velocity observer has been utilized. Stability of the closed loop system and boundedness of system states are proven via Lyapunov based arguments. The performance of the purposed observer-controller couple is then verified by a set of numerical simulations.