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Yangquan Chen - One of the best experts on this subject based on the ideXlab platform.

  • State-periodic adaptive compensation of cogging and Coulomb friction in permanent magnet Linear Motors
    Proceedings of the 2005 American Control Conference 2005., 2005
    Co-Authors: Yangquan Chen
    Abstract:

    This paper focuses on the state-periodic adaptive compensation of cogging and Coulomb friction for permanent magnet Linear Motors (PMLM) executing a task repeatedly. The cogging force is considered as a position dependent disturbance and the considered Coulomb friction is non-Lipschitz at zero velocity. The key idea of our disturbance compensation method is to use one trajectory-period past information along the state axis to update the current adaptation law. The new method consists of three different steps: firstly, in the first repetitive trajectory, an adaptive compensator is designed to guarantee the l/sub 2/-stability of the overall system. Secondly, from the second repetitive trajectory and onwards, a trajectory-periodic adaptive compensator is designed to stabilize the system. Finally, to make use of the stored past state-dependent cogging information, a search process is utilized for adapting the current cogging coefficient. The validity of our adaptive cogging and friction compensator is illustrated through a simulation example.

  • state periodic adaptive compensation of cogging and coulomb friction in permanent magnet Linear Motors
    IEEE Transactions on Magnetics, 2005
    Co-Authors: Yangquan Chen
    Abstract:

    This paper focuses on the state-periodic adaptive compensation of cogging and Coulomb friction for permanent-magnet Linear Motors (PMLMs) executing a task repeatedly. The cogging force is considered as a position-dependent disturbance and the Coulomb friction is non-Lipschitz at zero velocity. The key idea of our disturbance compensation method is to use past information for one trajectory period along the state axis to update the current adaptation law. The new method consists of three different steps: 1) in the first repetitive trajectory, an adaptive compensator is designed to guarantee the l/sub 2/-stability of the overall system; 2) from the second repetitive trajectory and onward, a trajectory-periodic adaptive compensator stabilizes the system; and 3) to make use of the stored past state-dependent cogging information, a search process is utilized for adapting the current cogging coefficient. We illustrate the validity of our state-periodic adaptive cogging and friction compensator by actual PMLM-model-based simulation.

Li Xu - One of the best experts on this subject based on the ideXlab platform.

  • adaptive robust motion control of Linear Motors for precision manufacturing
    Mechatronics, 2002
    Co-Authors: Li Xu
    Abstract:

    Linear Motors offer several advantages over their rotary counterparts in many precision manufacturing applications requiring Linear motion; Linear Motors can achieve a much higher speed and have the potential of gaining a higher load positioning accuracy due to the elimination of mechanical transmission mechanisms. However, these advantages are obtained at the expense of added difficulties in controlling such a system. Specifically, Linear Motors are more sensitive to disturbances and parameter variations. Furthermore, certain types of Linear Motors such as the iron core are subject to significant nonLinear effects due to periodic cogging force and force ripple. To address all these issues, the recently proposed adaptive robust control (ARC) strategy is applied and a discontinuous projection-based ARC controller is constructed. In particular, based on the special structures of various periodic nonLinear forces, design models consisting of known basis functions with unknown weights are used to approximate those unknown nonLinear forces. On-line parameter adaptation is then utilized to reduce the effect of various parametric uncertainties such as unknown weights, inertia, and motor parameters while certain robust control laws are used to handle the uncompensated uncertain nonLinearities effectively for high performance. The resulting ARC controller achieves a guaranteed transient performance and a guaranteed final tracking accuracy in the presence of both parametric uncertainties and uncertain nonLinearities. In addition, in the presence of parametric uncertainties, the controller achieves asymptotic output tracking. Extensive simulation results are shown to illustrate the effectiveness of the proposed algorithm.

  • Adaptive robust precision motion control of Linear Motors with ripple force compensations: theory and experiments
    Proceedings of the 2000. IEEE International Conference on Control Applications. Conference Proceedings (Cat. No.00CH37162), 2000
    Co-Authors: Li Xu
    Abstract:

    This paper studies the high performance robust motion control of Linear Motors which are subjected to significant force ripple. Based on the structural property of Linear Motors, some simple models with unknown weights are used to approximate the force ripple as well as other reproducible nonLinearities, such as friction. The unknown weights are adjusted online via certain parameter adaptation law to achieve an improved model compensation. The model approximation error as well as lumped disturbance are handled via certain robust control law to achieve a guaranteed robust performance. Experimental results are obtained for the motion control of an iron core Linear motor and verify the high performance of the proposed scheme.

  • adaptive robust precision motion control of Linear Motors with negligible electrical dynamics theory and experiments
    American Control Conference, 2000
    Co-Authors: Li Xu
    Abstract:

    This paper studies the high performance robust motion control of Linear Motors that have a negligible electrical dynamics. A discontinuous projection based adaptive robust controller (ARC) is first constructed. The controller guarantees a prescribed transient performance and final tracking accuracy in general while achieving asymptotic tracking in the presence of parametric uncertainties only. A desired compensation ARC scheme is then presented, in which the regressor is calculated using desired trajectory information only. The resulting controller has several implementation advantages. Both schemes are implemented and compared on an epoxy core Linear motor. Extensive comparative experimental results are presented to illustrate the effectiveness and the achievable control performance of the two ARC designs.

  • adaptive robust control of Linear Motors for precision manufacturing
    IFAC Proceedings Volumes, 1999
    Co-Authors: Li Xu
    Abstract:

    Abstract Linear Motors are sensitive to disturbances and parameter variations. Certain types of Linear Motors such as the iron core are also subject to nonLinear effects due to periodic cogging force and force ripple. An adaptive robust controller based on the discontinuous projection method is constructed to address these issues. In particular, based on the particular structures of various periodic nonLinear forces, design models consisting of known basis functions with unknown weights are used to approximate those unknown nonLinear forces. On-line parameter adaptation is then utilized to reduce the effect of various parametric uncertainties such as unknown weights, inertia, and motor parameters while certain robust control laws are used to handle the uncompensated uncertain nonLinearities effectively for high performance. Simulation results are shown to illustrate the effectiveness of the proposed algorithm.

Qingfeng Wang - One of the best experts on this subject based on the ideXlab platform.

  • adaptive robust precision motion control of Linear Motors with integrated compensation of nonLinearities and bearing flexible modes
    IEEE Transactions on Industrial Informatics, 2013
    Co-Authors: Zheng Chen, Qingfeng Wang
    Abstract:

    To realize the high performance potential of Linear motor drive systems, various nonLinearities inherited to the system and their compensations have been extensively studied during the past decade. However, existing research tends to focus on one or several types of nonLinearities at a time and thus do not offer a complete overall solution. This paper studies precision motion control of Linear Motors in the presence of parameter variations and disturbances. An adaptive robust control (ARC) algorithm with simultaneous compensation of all significant nonLinearities is developed. Those nonLinearities include Coulomb friction, cogging force, and nonLinear electromagnetic field effect. The proposed ARC with and without nonLinearity compensation have also been implemented on the Y-axis of a Linear-motor-driven industrial gantry. Comparative experimental results show that the proposed ARC algorithm with simultaneous compensation of all significant nonLinearities achieves better motion tracking performance than existing ones. In addition, high-frequency structural flexible modes due to bearing, which are neglected in the previous researches, are explicitly identified experimentally, and their effects are carefully examined. Theoretical analysis is then conducted to generate a set of practically useful guidelines on the tuning of controller gains to optimize the achievable performance in practice.

  • Adaptive robust precision motion control of Linear Motors with high frequency flexible modes
    2012 12th IEEE International Workshop on Advanced Motion Control (AMC), 2012
    Co-Authors: Zheng Chen, Qingfeng Wang
    Abstract:

    This paper studies precision motion control of Linear Motors in the presence of parameter variations, disturbances and various significant nonLinearity effects. An adaptive robust control (ARC) algorithm with integrated compensation of major nonLinearities ranging from Coulomb friction and cogging force to the nonLinear electromagnetic field effect is developed. High frequency structural flexible modes and dynamics in Linear Motors, which are neglected in the previous researches, are explicitly identified experimentally and their effects are carefully examined. With the knowledge of those high frequency dynamics, theoretical analysis is subsequently conducted to generate a set of practically useful guidelines on the tuning of controller gains in maximizing the achievable performance in practice. Comparative experiments of the propose ARC control law with different controller gains are carried out to illustrate the usefulness of the generated guidelines. In addition, to further push the achievable control performance, explicit compensation of the known high-frequency flexible modes and dynamics using pole/zero cancelation is also investigated, and its effectiveness is evaluated through comparative experimental results as well.

  • Adaptive robust precision motion control of Linear Motors with electromagnetic nonLinearity compensation
    2011 IEEE ASME International Conference on Advanced Intelligent Mechatronics (AIM), 2011
    Co-Authors: Zheng Chen, Qingfeng Wang
    Abstract:

    Iron-core Linear Motors have been widely used in high-speed/high-accuracy positioning systems due to the elimination of mechanical transmissions. Many control methodologies have been developed for Linear motor motion control, such as H∞ control, adaptive control and sliding mode control. Compensations of various nonLinearities such as frictions and cogging forces have also been carried out to obtain better tracking performance. However, the relationship between the driving current and the resulting motor force has been assumed to be Linear, which is invalid for high driving coil currents due to the saturating electromagnetic field effect. This paper focuses on the effective compensation of nonLinear electromagnetic field effect so that the system can be operated at even higher acceleration or heavier load without losing achievable control performance. Specifically, cubic polynomials are used for an effective approximation of the unknown inverse nonLinearity between the electromagnetic force and the driving current. The effectiveness of such an approximation is verified by off-line identification experiments. An adaptive robust control (ARC) algorithm with inversion compensation of nonLinear electro-magnetic force is then developed. Theoretically, the proposed ARC algorithm achieves a guaranteed transient and steady-state performance for position tracking, as well as zero steady-state tracking error when subjected to parametric uncertainties only. Comparative experiments of ARC with and without compensation of electromagnetic nonLinearity done on a Linear-motor-driven industrial gantry are shown. The results show that the proposed ARC algorithm achieves better tracking performance than existing ones, validating the effectiveness of the proposed approach in practical applications.

  • accurate motion control of Linear Motors with adaptive robust compensation of nonLinear electromagnetic field effect
    ASME 2011 Dynamic Systems and Control Conference and Bath ASME Symposium on Fluid Power and Motion Control Volume 1, 2011
    Co-Authors: Zheng Chen, Qingfeng Wang
    Abstract:

    Iron-core Linear Motors have been widely used in high-speed/high-accuracy positioning systems due to the elimination of mechanical transmissions. Many control methodologies have been developed for Linear motor motion control, such as H∞ control, adaptive control and sliding mode control. Compensations of various nonLinearities such as frictions and cogging forces have also been carried out to obtain better tracking performance. However, the relationship between the driving current and the resulting motor force has been assumed to be Linear, which is invalid for high driving coil currents due to the saturating electromagnetic field effect. This paper focuses on the effective compensation of nonLinear electromagnetic field effect so that the system can be operated at even higher acceleration or heavier load without losing achievable control performance. Specifically, cubic polynomials with unknown weights are used for an effective approximation of the unknown nonLinearity between the electromagnetic force and the driving current. The effectiveness of such an approximation is verified by off-line identification experiments. An adaptive robust control (ARC) algorithm with online tuning of the unknown weights and other system parameters is then developed to account for various uncertainties. Theoretically, the proposed ARC algorithm achieves a guaranteed transient and steady-state performance for position tracking, as well as zero steady-state tracking error when subjected to parametric uncertainties only. Comparative experiments of ARC with and without compensation of electromagnetic nonLinearity done on a Linear-motor-driven industrial gantry will be shown. The results show that the proposed ARC algorithm achieves better tracking performance than existing ones, validating the effectiveness of the proposed approach in practical applications.Copyright © 2011 by ASME

Po-huan Chou - One of the best experts on this subject based on the ideXlab platform.

  • DSP-based cross-coupled synchronous control for dual Linear Motors via intelligent complementary sliding mode control
    CHUSER 2012 - 2012 IEEE Colloquium on Humanities Science and Engineering Research, 2012
    Co-Authors: Po-huan Chou, Chin Sheng Chen, Faa-jeng Lin, Feng Chi Lee
    Abstract:

    A digital signal processor (DSP)-based cross-coupled intelligent complementary sliding mode control (ICSMC) system is proposed in this paper for the synchronous control of a dual Linear motor servo system. The dual Linear motor servo system with two parallel permanent magnet Linear synchronous Motors is installed in a gantry position stage. The dynamic model of single-axis motion control system with a lumped uncertainty, which comprises parameter variations, external disturbances, and nonLinear friction force, is introduced first. Then, to achieve an accurate trajectory tracking performance with robustness, a cross-coupled ICSMC is developed. In this approach, a Takagi–Sugeno–Kang-type fuzzy neural network estimator with accurate approximation capability is implemented to estimate the lumped uncertainty. Moreover, since a cross-coupled technology is incorporated into the proposed intelligent control scheme for the gantry position stage, both the position tracking and synchronous errors of the dual Linear Motors will simultaneously converge to zero. Furthermore, to effectively demonstrate the control performance of the proposed intelligent control approach, a 32-b floating-point DSP-based control computer is developed for the implementation of the proposed cross-coupled ICSMC system. Finally, some experimental results are illustrated to show the validity of the proposed control approach.

  • DSP-based cross-coupled synchronous control for dual Linear Motors via intelligent complementary sliding mode control
    2012 IEEE Colloquium on Humanities Science and Engineering (CHUSER), 2012
    Co-Authors: Po-huan Chou, Chin Sheng Chen
    Abstract:

    A digital signal processor (DSP)-based cross-coupled intelligent complementary sliding mode control (ICSMC) system is proposed in this study for the synchronous control of a dual Linear Motors servo system. The dual Linear Motors servo system with two parallel permanent magnet Linear synchronous Motors (PMLSMs) is installed in a gantry position stage. The dynamic model of single-axis motion control system with a lumped uncertainty, which comprises parameter variations, external disturbances and nonLinear friction force, is introduced first. Then, to achieve an accurate trajectory tracking performance with robustness, a cross-coupled ICSMC is developed. In this approach, a Takagi-Sugeno-Kang type fuzzy neural network (TSKFNN) estimator with accurate approximation capability is implemented to estimate the lumped uncertainty. Moreover, since a cross-coupled technology is incorporated into the proposed intelligent control scheme for the gantry position stage, both the position tracking error and synchronous error of the dual Linear Motors will converge to zero simultaneously. Finally, some experimental results are illustrated to show the validity of the proposed control approach.

  • DSP-based cross-coupled synchronous control for dual Linear Motors via functional link radial basis function network
    2011 IEEE International Conference on Fuzzy Systems (FUZZ-IEEE 2011), 2011
    Co-Authors: Chin Sheng Chen, Po-huan Chou
    Abstract:

    A digital signal processor (DSP)-based cross-coupled functional link radial basis function network (FLRBFN) control is proposed in this study for the synchronous control of a dual Linear Motors servo system which is installed in a gantry position stage. The dual Linear Motors servo system comprises two parallel permanent magnet Linear synchronous Motors (PMLSMs). First, the dynamics of the field-oriented control PMLSM servo drive with a lumped uncertainty, which contains parameter variations, external disturbance and friction force, is introduced. Then, to achieve accurate trajectory tracking performance with robustness, an intelligent control approach using FLRBFN is proposed for the field-oriented control PMLSM servo drive system. The proposed FLRBFN is a radial basis function network (RBFN) embedded with a functional link neural network (FLNN). The network structure and its on-line learning algorithms for connective weights, means and standard derivations are described in detail. Moreover, since a cross-coupled technology is incorporated into the proposed intelligent control scheme for the gantry position stage, both of the position tracking errors and synchronous errors of dual Linear Motors will converge to zero, simultaneously. Finally, some experimental results are illustrated to depict the validity of the proposed control approach.

  • digital signal processor based cross coupled synchronous control of dual Linear Motors via functional link radial basis function network
    Iet Control Theory and Applications, 2011
    Co-Authors: H J Hsieh, Po-huan Chou
    Abstract:

    A digital signal processor-based cross-coupled functional link (FL) radial basis function network (FLRBFN) control is proposed in this study for the synchronous control of a dual Linear Motors servo system that is installed in a gantry position stage. The dual Linear Motors servo system comprises two parallel permanent magnet Linear synchronous Motors (PMLSMs). First, the dynamics of the field-oriented control PMLSM servo drive with a lumped uncertainty, which contains parameter variations, external disturbance and friction force, is introduced. Then, to achieve accurate trajectory tracking performance with robustness, an intelligent control approach using FLRBFN is proposed for the field-oriented control PMLSM servo drive system. The proposed FLRBFN is a radial basis function network embedded with a FL neural network. Moreover, to guarantee the convergence of the FLRBFN, a discrete-type Lyapunov function is provided to determine the varied learning rates of the FLRBFN. In addition, since a cross-coupled technology is incorporated into the proposed intelligent control scheme for the gantry position stage, both the position tracking errors and synchronous errors of dual Linear Motors will converge to zero, simultaneously. Finally, some experimental results are illustrated to depict the validity of the proposed control approach.

Zheng Chen - One of the best experts on this subject based on the ideXlab platform.

  • adaptive robust precision motion control of Linear Motors with integrated compensation of nonLinearities and bearing flexible modes
    IEEE Transactions on Industrial Informatics, 2013
    Co-Authors: Zheng Chen, Qingfeng Wang
    Abstract:

    To realize the high performance potential of Linear motor drive systems, various nonLinearities inherited to the system and their compensations have been extensively studied during the past decade. However, existing research tends to focus on one or several types of nonLinearities at a time and thus do not offer a complete overall solution. This paper studies precision motion control of Linear Motors in the presence of parameter variations and disturbances. An adaptive robust control (ARC) algorithm with simultaneous compensation of all significant nonLinearities is developed. Those nonLinearities include Coulomb friction, cogging force, and nonLinear electromagnetic field effect. The proposed ARC with and without nonLinearity compensation have also been implemented on the Y-axis of a Linear-motor-driven industrial gantry. Comparative experimental results show that the proposed ARC algorithm with simultaneous compensation of all significant nonLinearities achieves better motion tracking performance than existing ones. In addition, high-frequency structural flexible modes due to bearing, which are neglected in the previous researches, are explicitly identified experimentally, and their effects are carefully examined. Theoretical analysis is then conducted to generate a set of practically useful guidelines on the tuning of controller gains to optimize the achievable performance in practice.

  • Adaptive robust precision motion control of Linear Motors with high frequency flexible modes
    2012 12th IEEE International Workshop on Advanced Motion Control (AMC), 2012
    Co-Authors: Zheng Chen, Qingfeng Wang
    Abstract:

    This paper studies precision motion control of Linear Motors in the presence of parameter variations, disturbances and various significant nonLinearity effects. An adaptive robust control (ARC) algorithm with integrated compensation of major nonLinearities ranging from Coulomb friction and cogging force to the nonLinear electromagnetic field effect is developed. High frequency structural flexible modes and dynamics in Linear Motors, which are neglected in the previous researches, are explicitly identified experimentally and their effects are carefully examined. With the knowledge of those high frequency dynamics, theoretical analysis is subsequently conducted to generate a set of practically useful guidelines on the tuning of controller gains in maximizing the achievable performance in practice. Comparative experiments of the propose ARC control law with different controller gains are carried out to illustrate the usefulness of the generated guidelines. In addition, to further push the achievable control performance, explicit compensation of the known high-frequency flexible modes and dynamics using pole/zero cancelation is also investigated, and its effectiveness is evaluated through comparative experimental results as well.

  • Adaptive robust precision motion control of Linear Motors with electromagnetic nonLinearity compensation
    2011 IEEE ASME International Conference on Advanced Intelligent Mechatronics (AIM), 2011
    Co-Authors: Zheng Chen, Qingfeng Wang
    Abstract:

    Iron-core Linear Motors have been widely used in high-speed/high-accuracy positioning systems due to the elimination of mechanical transmissions. Many control methodologies have been developed for Linear motor motion control, such as H∞ control, adaptive control and sliding mode control. Compensations of various nonLinearities such as frictions and cogging forces have also been carried out to obtain better tracking performance. However, the relationship between the driving current and the resulting motor force has been assumed to be Linear, which is invalid for high driving coil currents due to the saturating electromagnetic field effect. This paper focuses on the effective compensation of nonLinear electromagnetic field effect so that the system can be operated at even higher acceleration or heavier load without losing achievable control performance. Specifically, cubic polynomials are used for an effective approximation of the unknown inverse nonLinearity between the electromagnetic force and the driving current. The effectiveness of such an approximation is verified by off-line identification experiments. An adaptive robust control (ARC) algorithm with inversion compensation of nonLinear electro-magnetic force is then developed. Theoretically, the proposed ARC algorithm achieves a guaranteed transient and steady-state performance for position tracking, as well as zero steady-state tracking error when subjected to parametric uncertainties only. Comparative experiments of ARC with and without compensation of electromagnetic nonLinearity done on a Linear-motor-driven industrial gantry are shown. The results show that the proposed ARC algorithm achieves better tracking performance than existing ones, validating the effectiveness of the proposed approach in practical applications.

  • accurate motion control of Linear Motors with adaptive robust compensation of nonLinear electromagnetic field effect
    ASME 2011 Dynamic Systems and Control Conference and Bath ASME Symposium on Fluid Power and Motion Control Volume 1, 2011
    Co-Authors: Zheng Chen, Qingfeng Wang
    Abstract:

    Iron-core Linear Motors have been widely used in high-speed/high-accuracy positioning systems due to the elimination of mechanical transmissions. Many control methodologies have been developed for Linear motor motion control, such as H∞ control, adaptive control and sliding mode control. Compensations of various nonLinearities such as frictions and cogging forces have also been carried out to obtain better tracking performance. However, the relationship between the driving current and the resulting motor force has been assumed to be Linear, which is invalid for high driving coil currents due to the saturating electromagnetic field effect. This paper focuses on the effective compensation of nonLinear electromagnetic field effect so that the system can be operated at even higher acceleration or heavier load without losing achievable control performance. Specifically, cubic polynomials with unknown weights are used for an effective approximation of the unknown nonLinearity between the electromagnetic force and the driving current. The effectiveness of such an approximation is verified by off-line identification experiments. An adaptive robust control (ARC) algorithm with online tuning of the unknown weights and other system parameters is then developed to account for various uncertainties. Theoretically, the proposed ARC algorithm achieves a guaranteed transient and steady-state performance for position tracking, as well as zero steady-state tracking error when subjected to parametric uncertainties only. Comparative experiments of ARC with and without compensation of electromagnetic nonLinearity done on a Linear-motor-driven industrial gantry will be shown. The results show that the proposed ARC algorithm achieves better tracking performance than existing ones, validating the effectiveness of the proposed approach in practical applications.Copyright © 2011 by ASME