Trajectory Tracking of Flexible-Joint Robots Actuated by PMSM via a Novel Smooth Switching Control Strategy

This paper presents the trajectory tracking control of a flexible-joint manipulator driven by permanent magnet synchronous motor (PMSM). Combining the PMSM electrical equation and mechanical equation of robotic manipulators, a novel smooth switching control scheme is proposed. Firstly, the position loop controller of the system is designed, with an improved hierarchical sliding mode control (IHSMC) algorithm proposed to further the response speed of the system, additionally, a robust interconnection and damping assignment passivity-based controller (IDA-PBC) is designed to improve the steady state performance of the system. Then, the IDA-PBC control strategy is leveraged to design the current loop controller of the system, on which basis a hybrid controller with smooth switching is designed. Furthermore, Gaussian function is applied as the smooth switching function of the hybrid controller to promote the switching performance. As a result, the hybrid controller has both good dynamic and steady performance. The simulation results verify the effectiveness of the algorithms.

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Smooth-Switching Control of Robot-Based Permanent-Magnet Synchronous Motors via Port-Controlled Hamiltonian and Feedback Linearization

Energies ◽

10.3390/en13215731 ◽

2020 ◽

Vol 13 (21) ◽

pp. 5731

Author(s):

Anxing Liu ◽

Haisheng Yu

Keyword(s):

Control Strategy ◽

Feedback Linearization ◽

Dynamic Performance ◽

Switching Control ◽

Switching Function ◽

Complete Model ◽

Robot System ◽

Permanent Magnet Synchronous Motors ◽

Loop Feedback ◽

Smooth Switching

To solve the contradiction between dynamic performance and steady-state performance of the robot system, a smooth-switching control strategy is proposed. By combining robot and motor model, the complete model of the robot driving system is established. The single-loop Feedback Linearization (FL) controller and Port-Controlled Hamiltonian (PCH) controller based on the complete model are derived to ensure the rapidity and stability of the system respectively. A smooth-switching function based on position error is designed. It can ensure the smooth-switching between two controllers and avoid the instability caused by switch-switching. The proposed algorithm can make the robot system have good dynamic and steady performance. Simulation and experiment results demonstrate the effectiveness of the smooth-switch control strategy.

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Research on an Improved Sliding Mode Sensorless Six-Phase PMSM Control Strategy Based on ESO

Electronics ◽

10.3390/electronics10111292 ◽

2021 ◽

Vol 10 (11) ◽

pp. 1292

Author(s):

Hanying Gao ◽

Guoqiang Zhang ◽

Wenxue Wang ◽

Xuechen Liu

Keyword(s):

Control System ◽

Control Strategy ◽

Sliding Mode ◽

High Reliability ◽

Permanent Magnet Synchronous Motor ◽

Torque Ripple ◽

Estimation Accuracy ◽

Switching Function ◽

Motor Speed ◽

Rotor Position

The six-phase motor control system has low torque ripple, low harmonic content, and high reliability; therefore, it is suitable for electric vehicles, aerospace, and other applications requiring high power output and reliability. This study presents a superior sensorless control system for a six-phase permanent magnet synchronous motor (PMSM). The mathematical model of a PMSM in a stationary coordinate system is presented. The information of motor speed and position is obtained by using a sliding mode observer (SMO). As torque ripple and harmonic components affect the back electromotive force (BEMF) estimated value through the traditional SMO, the function of the frequency-variable tracker of the stator current (FVTSC) is used instead of the traditional switching function. By improving the SMO method, the BEMF is estimated independently, and its precision is maintained under startup or variable-speed states. In order to improve the estimation accuracy and resistance ability of the observer, the rotor position error was taken as the disturbance term, and the third-order extended state observer (ESO) was constructed to estimate the rotational speed and rotor position through the motor mechanical motion equation. Finally, the effectiveness of the method is verified by simulation and experiment results. The proposed control strategy can effectively improve the dynamic and static performance of PMSM.

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Event-triggered integral sliding mode fixed time control for trajectory tracking of autonomous underwater vehicle

Transactions of the Institute of Measurement and Control ◽

10.1177/0142331221994380 ◽

2021 ◽

pp. 014233122199438

Author(s):

Bo Su ◽

Hongbin Wang ◽

Ning Li

Keyword(s):

Trajectory Tracking ◽

Control Strategy ◽

Autonomous Underwater Vehicle ◽

Sliding Mode ◽

Fixed Time ◽

Underwater Vehicle ◽

Reference Trajectory ◽

Integral Sliding Mode ◽

Time Control ◽

Event Triggered

In this paper, an event-triggered integral sliding mode fixed-time control method for trajectory tracking problem of autonomous underwater vehicle (AUV) with disturbance is investigated. Initially, the global fixed time stability is ensured with conventional periodic sampling method for reference trajectory tracking. By introducing fixed time integral sliding mode manifold, fixed time control strategy is expressed for the AUV, which can effectively eliminate the singularity. Correspondingly, in order to reduce the damage caused by chattering phenomenon, an adaptive fixed-time method is proposed based on the designed continuous integral terminal sliding mode (ITSM) to ensure that the trajectory tracking for AUV is achieved in fixed-time with external disturbance. In order to reduce resource consumption in the process of transmission network, the event-triggered sliding mode control strategy is designed which condition is triggered by an event. Also, Zeno behavior is avoided by proof of theoretical. It is shown that the upper bounds of settling time are only dependent on the parameters of controller. Theoretical analysis and simulation experiment results show that the presented methods can realize the control object.

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Trajectory Tracking of Underactuated Surface Vessels Based on Hierarchical Sliding Mode

Volume 8B: Ocean Engineering ◽

10.1115/omae2014-24236 ◽

2014 ◽

Author(s):

Cheng Liu ◽

Zaojian Zou ◽

Jianchuan Yin

Keyword(s):

Trajectory Tracking ◽

Degrees Of Freedom ◽

Closed Loop ◽

Sliding Mode ◽

Underactuated System ◽

Sliding Mode Controller ◽

Control Field ◽

Surface Vessels ◽

Underactuated Surface Vessels ◽

Hierarchical Sliding Mode

Trajectory tracking is an importance practice in ship motion control field. It attracts more attention recently due to its difficulties. Trajectory tracking requires the ship to arrive pinpoint location at exact time. It is a underactuated system because the degrees of freedom of control inputs are fewer than the degrees of freedom that needed to be controlled. In this paper, a hierarchical sliding mode controller and a common sliding mode controller are proposed to deal with the trajectory tracking problem of underactuated surface vessels. Simulation results validate the tracking performance of the proposed controllers. The closed-loop stability is testified by the Lyapunov stability theorem.

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Development, Dynamic Modeling, and Multi-Modal Control of a Therapeutic Exoskeleton for Upper Limb Rehabilitation Training

Sensors ◽

10.3390/s18113611 ◽

2018 ◽

Vol 18 (11) ◽

pp. 3611 ◽

Cited By ~ 7

Author(s):

Qingcong Wu ◽

Hongtao Wu

Keyword(s):

Dynamic Modeling ◽

Upper Limb ◽

Trajectory Tracking ◽

Control Strategy ◽

Sliding Mode ◽

Human Robot Interaction ◽

Sliding Mode Controller ◽

Modal Control ◽

Cooperative Training ◽

Passive Training

Robot-assisted training is a promising technology in clinical rehabilitation providing effective treatment to the patients with motor disability. In this paper, a multi-modal control strategy for a therapeutic upper limb exoskeleton is proposed to assist the disabled persons perform patient-passive training and patient-cooperative training. A comprehensive overview of the exoskeleton with seven actuated degrees of freedom is introduced. The dynamic modeling and parameters identification strategies of the human-robot interaction system are analyzed. Moreover, an adaptive sliding mode controller with disturbance observer (ASMCDO) is developed to ensure the position control accuracy in patient-passive training. A cascade-proportional-integral-derivative (CPID)-based impedance controller with graphical game-like interface is designed to improve interaction compliance and motivate the active participation of patients in patient-cooperative training. Three typical experiments are conducted to verify the feasibility of the proposed control strategy, including the trajectory tracking experiments, the trajectory tracking experiments with impedance adjustment, and the intention-based training experiments. The experimental results suggest that the tracking error of ASMCDO controller is smaller than that of terminal sliding mode controller. By optimally changing the impedance parameters of CPID-based impedance controller, the training intensity can be adjusted to meet the requirement of different patients.

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