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

Sensors ◽  
2018 ◽  
Vol 18 (11) ◽  
pp. 3611 ◽  
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.

scholarly journals Trajectory Tracking Control of Intelligent Electric Vehicles Based on the Adaptive Spiral Sliding Mode

2021 ◽  
Vol 11 (24) ◽  
pp. 11739
Author(s):  
Yanxin Nie ◽  
Minglu Zhang ◽  
Xiaojun Zhang
Keyword(s):  
Electric Vehicles ◽  
Trajectory Tracking ◽  
Control Strategy ◽  
Sliding Mode ◽  
Sliding Mode Controller ◽  
Lateral Deviation ◽  
Distribution Method ◽  
Tire Force ◽  
Tracking Model ◽  
Vehicle Trajectory

Aiming at the multi-objective control problem of the tracking effect and vehicle stability in the process of intelligent vehicle trajectory tracking, a coordinated control strategy of the trajectory tracking and stability of intelligent electric vehicles is proposed based on the hierarchical control theory. The vehicle dynamics model and trajectory tracking model are established. In order to tackle the chattering problem in the traditional sliding mode controller, an Adaptive Spiral Sliding Mode controller is designed by taking the derivative of the controller as the upper controller, which is intended to reduce the heading deviation and lateral deviation in the trajectory tracking process whilst ensuring the stability of the vehicle itself. In the lower controller, a four-wheel tire force optimal distribution method is designed. According to the requirements of the upper controller, combined with the yaw stability of the vehicle, the directional control distribution of the four-wheel tire force is realized. A joint simulation model was built based on CarSim and Simulink, and simulation experiments were performed. The results show that the proposed control strategy can effectively control the heading deviation and lateral deviation in the vehicle trajectory tracking while ensuring the lateral stability of the vehicle.

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

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.

scholarly journals A New Control Strategy for Bi-directional DC/DC Converter in DC Microgrid

2021 ◽  
Vol 233 ◽  
pp. 01051
Author(s):  
Tianze Miao ◽  
Xiaona Liu ◽  
Siyuan Liu ◽  
Lihua Wang
Keyword(s):  
Steady State ◽  
Control Strategy ◽  
Feedback Linearization ◽  
Sliding Mode ◽  
Response Speed ◽  
Fast Response ◽  
Sliding Mode Controller ◽  
Exponential Approximation ◽  
Dc Microgrid ◽  
Simulation Results

The bi-directional DC / DC converter in DC microgrid is a typical nonlinear system which has large voltage disturbance during lead accumulator charging and discharging. In order to solve the problem of voltage disturbance, the linearization of the converter is realized by exact feedback linearization, and the sliding mode controller is designed by using exponential approximation law. The simulation results show that the method has fast response speed, strong anti-interference ability and good steady-state characteristics.

scholarly journals Trajectory tracking control for chain-series robot manipulator: Robust adaptive fuzzy terminal sliding mode control with low-pass filter

2020 ◽  
Vol 17 (3) ◽  
pp. 172988142091698 ◽  
Author(s):  
Pengcheng Wang ◽  
Dengfeng Zhang ◽  
Baochun Lu
Keyword(s):  
Trajectory Tracking ◽  
Sliding Mode ◽  
Sliding Mode Controller ◽  
Continuous Control ◽  
Terminal Sliding Mode ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Adaptive Fuzzy ◽  
Low Pass ◽  
Robust Adaptive

This article investigates a difficult problem which focuses on the external disturbance and dynamic uncertainty in the process of trajectory tracking. This article presents a robust adaptive fuzzy terminal sliding mode controller with low-pass filter. The low-pass filter can provide smooth position and speed signals. The fuzzy terminal sliding mode controller can achieve fast convergence and desirable tracking precision. Chattering is eliminated with continuous control law, due to high-frequency switching terms contained in the first derivative of actual control signals. Ignoring the prior knowledge upper bound, the controller can reduce the influence of the uncertain kinematics and dynamics in the actual situation. Finally, the experiment is carried out and the results show the performance of the proposed controller.

Trajectory Tracking of Underactuated Surface Vessels Based on Hierarchical Sliding Mode

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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