The Experts below are selected from a list of 324 Experts worldwide ranked by ideXlab platform
Gerd Hirzinger - One of the best experts on this subject based on the ideXlab platform.
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on the passivity based impedance control of flexible joint robots
IEEE Transactions on Robotics, 2008Co-Authors: Alin Albuschaffer, Andreas Kugi, Gerd HirzingerAbstract:In this paper, a novel type of impedance controllers for flexible joint robots is proposed. As a target impedance, a desired stiffness and damping are considered without Inertia shaping. For this problem, two controllers of different complexity are proposed. Both have a cascaded structure with an inner torque feedback loop and an outer impedance controller. For the torque feedback, a physical interpretation as a scaling of the Motor Inertia is given, which allows to incorporate the torque feedback into a passivity-based analysis. The outer impedance control law is then designed differently for the two controllers. In the first approach, the stiffness and damping terms and the gravity compensation term are designed separately. This outer control loop uses only the Motor position and velocity, but no noncollocated feedback of the joint torques or link side positions. In combination with the physical interpretation of torque feedback, this allows us to give a proof of the asymptotic stability of the closed-loop system based on the passivity properties of the system. The second control law is a refinement of this approach, in which the gravity compensation and the stiffness implementation are designed in a combined way. Thereby, a desired static stiffness relationship is obtained exactly. Additionally, some extensions of the controller to viscoelastic joints and to Cartesian impedance control are given. Finally, some experiments with the German Aerospace Center (DLR) lightweight robots verify the developed controllers and show the efficiency of the proposed control approach.
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a unified passivity based control framework for position torque and impedance control of flexible joint robots
The International Journal of Robotics Research, 2007Co-Authors: Alin Albuschaffer, Gerd HirzingerAbstract:This paper describes a general passivity-based framework for the control of flexible joint robots. Recent results on torque, position, as well as impedance control of flexible joint robots are summarized, and the relations between the individual contributions are highlighted. It is shown that an inner torque feedback loop can be incorporated into a passivity-based analysis by interpreting torque feedback in terms of shaping of the Motor Inertia. This result, which implicitly was already included in earlier work on torque and position control, can also be used for the design of impedance controllers. For impedance control, furthermore, potential energy shaping is of special interest. It is shown how, based only on the Motor angles, a potential function can be designed which simultaneously incorporates gravity compensation and a desired Cartesian stiffness relation for the link angles. All the presented controllers were experimentally evaluated on DLR lightweight robots and their performance and robustness shown with respect to uncertain model parameters. Experimental results with position controllers as well as an impact experiment are presented briefly, and an overview of several applications is given in which the controllers have been applied.
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ICRA - A passivity based Cartesian impedance controller for flexible joint robots - part I: torque feedback and gravity compensation
IEEE International Conference on Robotics and Automation 2004. Proceedings. ICRA '04. 2004, 2004Co-Authors: Christian Ott, Alin Albu-schaffer, Andreas Kugi, S. Stamigioli, Gerd HirzingerAbstract:In this paper a novel approach to the Cartesian impedance control problem for robots with flexible joints is presented. The proposed controller structure is based on simple physical considerations, which are motivating the extension of classical position feedback by an additional feedback of the joint torques. The torque feedback action can be interpreted as a scaling of the apparent Motor Inertia. Furthermore the problem of gravity compensation is addressed. Finally, it is shown that the closed loop system can be seen as a feedback interconnection of passive systems. Based on this passivity property a proof of asymptotic stability is presented.
Hou-tsan Lee - One of the best experts on this subject based on the ideXlab platform.
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ADAPTIVE SPR SPEED/POSITION CONTROL OF INDUCTION Motor
IFAC Proceedings Volumes, 2016Co-Authors: Hou-tsan Lee, Su-hau HsuAbstract:Abstract This paper proposes an adaptive speed/position tracking control of an induction Motor subject to unknown load torque via strictly positive real (SPR) analysis. The controller is developed under a special nonlinear coordinate transform such that either speed or position control objective can be fulfilled. The underlying design concepts are to endow the close-loop system while under lack of knowledge of some key system parameters, such as the rotor resistance, Motor Inertia and Motor damping coefficient. The proposed control scheme comes along with a thorough proof derived based on Lyapunov stability theory. The experimental results are also given to validate the effectiveness of the presented control scheme.
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Adaptive speed/position control of induction Motor based on SPR approach
International Journal of Control, 2014Co-Authors: Hou-tsan LeeAbstract:A sensorless speed/position tracking control scheme for induction Motors is proposed subject to unknown load torque via adaptive strictly positive real (SPR) approach design. A special nonlinear coordinate transform is first provided to reform the dynamical model of the induction Motor. The information on rotor fluxes can thus be derived from the dynamical model to decide on the proportion of input voltage in the d-q frame under the constraint of the maximum power transfer property of induction Motors. Based on the SPR approach, the speed and position control objectives can be achieved. The proposed control scheme is to provide the speed/position control of induction Motors while lacking the knowledge of some mechanical system parameters, such as the Motor Inertia, Motor damping coefficient, and the unknown payload. The adaptive control technique is thus involved in the field oriented control scheme to deal with the unknown parameters. The thorough proof is derived to guarantee the stability of the speed ...
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Adaptive PC-based backstepping position control of induction Motor
International Journal of Power Electronics, 2011Co-Authors: Hou-tsan LeeAbstract:An adaptive position tracking control scheme for induction Motors is proposed subject to unknown load torque via adaptive backstepping design. An observer derived from the dynamical model is also given to provide the information of rotor flux angle which decides the proportion of input voltage in d-q frame. Besides, the controller is developed under a special non-linear coordinate transform such that position control objective can be fulfilled with backstepping approach. The underlying design concept is to endow the closed-loop system while lacking the knowledge of some mechanical system parameters, such as the Motor Inertia Motor damping coefficient, and the unknown payload. The proposed control scheme comes along with a thorough proof based on Lyapunov stability theory. PC-based experimental results are also given to validate the effectiveness of the proposed control scheme.
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CDC - Sensorless Adaptive Backstepping Speed Control of Induction Motor
Proceedings of the 45th IEEE Conference on Decision and Control, 2006Co-Authors: Hou-tsan Lee, Feng-li LianAbstract:This paper proposes an adaptive speed tracking control scheme for an induction Motor subject to unknown load torque via backstepping analysis. The controller is developed under a special nonlinear coordinate transform such that speed control objective can be fulfilled. The underlying design concept is to endow the closed-loop system while lacking the knowledge of some key system parameters, such as the rotor resistance, Motor Inertia, and Motor damping coefficient. The proposed control scheme comes along with a thorough proof derived based on Lyapunov stability theory. Experimental results are also given to validate the effectiveness of the proposed control scheme.
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Nonlinear adaptive control of induction Motor with unknown rotor resistance
Proceedings of the 41st IEEE Conference on Decision and Control 2002., 2002Co-Authors: Hou-tsan Lee, Lee-jyi WangAbstract:The paper proposes an adaptive speed/position tracking control of an induction Motor subject to unknown load torque. The controller is developed based on a dynamic model obtained from the d-q-axis model (w.r.t. the stationary reference frame) of the Motor under a special nonlinear coordinate transform so that either the speed or position control objective can be fulfilled. The underlying design concept is to endow the closed-loop system with a so-called maximal power transfer property while under lack of knowledge of some key system parameters, such as the rotor resistance, Motor Inertia and Motor damping coefficient. To be rigorous, the proposed control scheme comes with a thorough proof derived based on Lyapunov stability theory. Numerical simulations and experimental results are also given to validate the effectiveness of the presented control scheme.
Kyo-beum Lee - One of the best experts on this subject based on the ideXlab platform.
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Robust and stable disturbance observer of servo system for low speed operation using the radial basis function network
Fourtieth IAS Annual Meeting. Conference Record of the 2005 Industry Applications Conference 2005., 2005Co-Authors: Kyo-beum Lee, Frede BlaabjergAbstract:A new scheme to estimate the moment of Inertia in the servo Motor drive system in very low speed is proposed in this paper. The speed estimation scheme in most servo drive systems for low speed operation is sensitive to the variation of machine parameter, especially the moment of Inertia. To estimate the Motor Inertia value, the observer using the radial basis function network (RBFN) is applied. A control law for stabilizing the system and adaptive laws for updating both of the weights in the RBFN and a bounding constant are established so that the whole closed-loop system is stable in the sense of Lyapunov. The effectiveness of the proposed Inertia estimation is verified by simulations and experiments. It is concluded that the speed control performance in low speed region is improved with the proposed disturbance observer using RBFN.
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Disturbance observer that uses radial basis function networks for the low speed control of a servo Motor
IEE Proceedings - Control Theory and Applications, 2005Co-Authors: Kyo-beum LeeAbstract:A scheme to estimate the moment of Inertia in a servo Motor drive system at very low speed is proposed. The typical speed estimation scheme used in most servo systems operated at low speed is highly sensitive to variations in the moment of Inertia. An observer that uses a radial basis function network to estimate the Motor Inertia value is proposed. The effectiveness of this observer is confirmed by both simulations and experiments.
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Performance improvement of servo machine for low speed operation using RBFN disturbance observer
30th Annual Conference of IEEE Industrial Electronics Society 2004. IECON 2004, 2004Co-Authors: Kyo-beum Lee, Frede BlaabjergAbstract:A new scheme to estimate the moment of Inertia in the servo Motor drive system in very low speed is proposed in this paper. The typical speed estimation scheme in most servo system for low speed operation is sensitive to the variation of machine parameters, especially the moment of Inertia. To estimate the Motor Inertia value, the observer using the radial basis function networks (RBFN) is applied. The effectiveness of the proposed Inertia estimation method is verified by experiments. It is concluded that the speed control performance in the low speed region is improved with the proposed disturbance observer using RBFN.
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Improvement of low speed operation of electric machine with an Inertia identification using ROELO
IEE Proceedings - Electric Power Applications, 2004Co-Authors: Kyo-beum Lee, Ji-yoon Yoo, Joong-ho Song, Ick ChoyAbstract:A new scheme to estimate the moment of Inertia in the Motor drive system in very low speed is proposed. The simple speed estimation scheme, which is used in most servo systems for low-speed operation, is sensitivity to variations in machine parameters especially the moment of Inertia. To estimate the Motor Inertia value, a reduced-order extended Luenberger observer (ROELO) is applied. The effectiveness of the proposed ROELO is verified by simulation and experiment.
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An Inertia identification using ROELO for low speed control of electric machine
Eighteenth Annual IEEE Applied Power Electronics Conference and Exposition 2003. APEC '03., 2003Co-Authors: Kyo-beum Lee, Joong-ho Song, Ick Choy, Ji-yoon YooAbstract:A new scheme to estimate the moment of Inertia in the Motor drive system in very low speed is proposed in this paper. The simple speed estimation scheme, which is usually used in most servo system for low speed operation, is sensitive to the variation of the machine parameter, especially the moment of Inertia. To estimate the Motor Inertia value, reduced-order extended Luenberger observer (ROELO) is applied. The effectiveness of the proposed ROELO is applied by simulations.
Alin Albuschaffer - One of the best experts on this subject based on the ideXlab platform.
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on the passivity based impedance control of flexible joint robots
IEEE Transactions on Robotics, 2008Co-Authors: Alin Albuschaffer, Andreas Kugi, Gerd HirzingerAbstract:In this paper, a novel type of impedance controllers for flexible joint robots is proposed. As a target impedance, a desired stiffness and damping are considered without Inertia shaping. For this problem, two controllers of different complexity are proposed. Both have a cascaded structure with an inner torque feedback loop and an outer impedance controller. For the torque feedback, a physical interpretation as a scaling of the Motor Inertia is given, which allows to incorporate the torque feedback into a passivity-based analysis. The outer impedance control law is then designed differently for the two controllers. In the first approach, the stiffness and damping terms and the gravity compensation term are designed separately. This outer control loop uses only the Motor position and velocity, but no noncollocated feedback of the joint torques or link side positions. In combination with the physical interpretation of torque feedback, this allows us to give a proof of the asymptotic stability of the closed-loop system based on the passivity properties of the system. The second control law is a refinement of this approach, in which the gravity compensation and the stiffness implementation are designed in a combined way. Thereby, a desired static stiffness relationship is obtained exactly. Additionally, some extensions of the controller to viscoelastic joints and to Cartesian impedance control are given. Finally, some experiments with the German Aerospace Center (DLR) lightweight robots verify the developed controllers and show the efficiency of the proposed control approach.
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a unified passivity based control framework for position torque and impedance control of flexible joint robots
The International Journal of Robotics Research, 2007Co-Authors: Alin Albuschaffer, Gerd HirzingerAbstract:This paper describes a general passivity-based framework for the control of flexible joint robots. Recent results on torque, position, as well as impedance control of flexible joint robots are summarized, and the relations between the individual contributions are highlighted. It is shown that an inner torque feedback loop can be incorporated into a passivity-based analysis by interpreting torque feedback in terms of shaping of the Motor Inertia. This result, which implicitly was already included in earlier work on torque and position control, can also be used for the design of impedance controllers. For impedance control, furthermore, potential energy shaping is of special interest. It is shown how, based only on the Motor angles, a potential function can be designed which simultaneously incorporates gravity compensation and a desired Cartesian stiffness relation for the link angles. All the presented controllers were experimentally evaluated on DLR lightweight robots and their performance and robustness shown with respect to uncertain model parameters. Experimental results with position controllers as well as an impact experiment are presented briefly, and an overview of several applications is given in which the controllers have been applied.
Frede Blaabjerg - One of the best experts on this subject based on the ideXlab platform.
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robust and stable disturbance observer of servo system for low speed operation
IEEE Transactions on Industry Applications, 2007Co-Authors: Frede BlaabjergAbstract:A new scheme to estimate the moment of Inertia in the servo Motor drive system in very low speed is proposed in this paper. The speed estimation scheme in most servo drive systems for low-speed operation is sensitive to the variation of machine parameter, especially the moment of Inertia. To estimate the Motor Inertia value, the observer using the Radial Basis Function Network (RBFN) is applied. A control law for stabilizing the system and adaptive laws for updating both of the weights in the RBFN and a bounding constant are established so that the whole closed-loop system is stable in the sense of Lyapunov. The effectiveness of the proposed Inertia estimation is verified by simulations and experiments
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Robust and stable disturbance observer of servo system for low speed operation using the radial basis function network
Fourtieth IAS Annual Meeting. Conference Record of the 2005 Industry Applications Conference 2005., 2005Co-Authors: Kyo-beum Lee, Frede BlaabjergAbstract:A new scheme to estimate the moment of Inertia in the servo Motor drive system in very low speed is proposed in this paper. The speed estimation scheme in most servo drive systems for low speed operation is sensitive to the variation of machine parameter, especially the moment of Inertia. To estimate the Motor Inertia value, the observer using the radial basis function network (RBFN) is applied. A control law for stabilizing the system and adaptive laws for updating both of the weights in the RBFN and a bounding constant are established so that the whole closed-loop system is stable in the sense of Lyapunov. The effectiveness of the proposed Inertia estimation is verified by simulations and experiments. It is concluded that the speed control performance in low speed region is improved with the proposed disturbance observer using RBFN.
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Performance improvement of servo machine for low speed operation using RBFN disturbance observer
30th Annual Conference of IEEE Industrial Electronics Society 2004. IECON 2004, 2004Co-Authors: Kyo-beum Lee, Frede BlaabjergAbstract:A new scheme to estimate the moment of Inertia in the servo Motor drive system in very low speed is proposed in this paper. The typical speed estimation scheme in most servo system for low speed operation is sensitive to the variation of machine parameters, especially the moment of Inertia. To estimate the Motor Inertia value, the observer using the radial basis function networks (RBFN) is applied. The effectiveness of the proposed Inertia estimation method is verified by experiments. It is concluded that the speed control performance in the low speed region is improved with the proposed disturbance observer using RBFN.