scholarly journals Prescribed Performance Control for the Upper-Limb Exoskeleton System in Passive Rehabilitation Training Tasks

2021 ◽  
Vol 11 (21) ◽  
pp. 10174
Author(s):  
Zhirui Zhao ◽  
Jichun Xiao ◽  
Hongyun Jia ◽  
Hang Zhang ◽  
Lina Hao
Keyword(s):  
Upper Limb ◽  
Control Method ◽  
Controller Design ◽  
Sliding Mode ◽  
Tracking Error ◽  
Adaptive Sliding Mode Control ◽  
Model Parameters ◽  
Prescribed Performance ◽  
Upper Limb Exoskeleton ◽  
Model Free

In this study, a model-free adaptive sliding mode control method was developed in combination with the prescribed performance method. On this basis, this study attempted to fulfill the joint position tracking trajectory task for the one-degree of freedom (DOF) upper-limb exoskeleton in passive robot-assisted rehabilitation. The proposed method is capable of addressing the defect of the initial error in the controller design and the application by adopting a tuning function, as compared with other prescribed performance methods. Moreover, the method developed here was not determined by the dynamic model parameters, which merely exploit the input and output data. Theoretically, the stability exhibited by the proposed controller and the tracking performance can be demonstrated. From the experimental results, the root mean square of the tracking error is equal to 1.06 degrees, and the steady-state tracking error converges to 1.91 degrees. These results can verify the expected performance of the developed control method.

scholarly journals Adaptive Sliding Mode Control Method for Z-Axis Vibrating Gyroscope Using Prescribed Performance Approach

2020 ◽  
Vol 10 (14) ◽  
pp. 4779 ◽  
Author(s):  
Cheng Lu ◽  
Liang Hua ◽  
Xinsong Zhang ◽  
Huiming Wang ◽  
Yunxiang Guo
Keyword(s):  
Sliding Mode Control ◽  
Error Bound ◽  
Control Method ◽  
Sliding Mode ◽  
Tracking Error ◽  
Adaptive Sliding Mode Control ◽  
Performance Control ◽  
Prescribed Performance ◽  
Adaptive Sliding Mode ◽  
Mode Control

This paper investigates one kind of high performance control methods for Micro-Electro-Mechanical-System (MEMS) gyroscopes using adaptive sliding mode control (ASMC) scheme with prescribed performance. Prescribed performance control (PPC) method is combined with conventional ASMC method to provide quantitative analysis of gyroscope tracking error performances in terms of specified tracking error bound and specified error convergence rate. The new derived adaptive prescribed performance sliding mode control (APPSMC) can maintain a satisfactory control performance which guarantees system tracking error, at any time, to be within a predefined error bound and the error convergences faster than the error bound. Besides, adaptive control (AC) technique is integrated with PPC to online tune controller parameters, which will converge to their true values at last. The stability of the control system is proved in the Lyapunov stability framework and simulation results on a Z-axis MEMS gyroscope is conducted to validate the effectiveness of the proposed control approach.

scholarly journals Adaptive Sliding Mode Control for a Class of Manipulator Systems with Output Constraint

Complexity ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Guangshi Li
Keyword(s):  
Sliding Mode Control ◽  
Control Method ◽  
Sliding Mode ◽  
Tracking Error ◽  
Lyapunov Stability Theory ◽  
Adaptive Sliding Mode Control ◽  
Compact Set ◽  
Adaptive Sliding Mode ◽  
Mode Control ◽  
System Output

In this paper, an adaptive sliding mode control method based on neural networks is presented for a class of manipulator systems. The main characteristic of the discussed system is that the output variable is required to keep within a constraint set. In order to ensure that the system output meets the time-varying constraint condition, the asymmetric barrier Lyapunov function is selected in the design process. According to Lyapunov stability theory, the stability of the closed-loop system is analyzed. It is demonstrated that all signals in the resulted system are bounded, the tracking error converges to a small compact set, and the system output limits in its constrained set. Finally, the simulation example is used to show the effectiveness of the presented control strategy.

Design of adaptive sliding mode controller applied to ultrasonic motor

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Gangfeng Yan
Keyword(s):  
Sliding Mode Control ◽  
Control Method ◽  
Sliding Mode ◽  
Tracking Error ◽  
Adaptive Sliding Mode Control ◽  
Sliding Mode Controller ◽  
Control Parameters ◽  
Content Type ◽  
Adaptive Sliding Mode ◽  
Mode Control

Purpose The purpose of this paper is to achieve high-precision sliding mode control without chattering; the control parameters are easy to adjust, and the entire controller is easy to use in engineering practice. Design/methodology/approach Using double sliding mode surfaces, the gain of the control signal can be adjusted adaptively according to the error signal. A kind of sliding mode controller without chattering is designed and applied to the control of ultrasonic motors. Findings The results show that for a position signal with a tracking amplitude of 35 mm, the traditional sliding mode control method has a maximum tracking error of 0.3326 mm under the premise of small chattering; the boundary layer sliding mode control method has a maximum tracking error of 0.3927 mm without chattering, and the maximum tracking error of continuous switching adaptive sliding mode control is 0.1589 mm, and there is no chattering. Under the same control parameters, after adding a load of 0.5 kg, the maximum tracking errors of the traditional sliding mode control method, the boundary layer sliding mode control method and the continuous switching adaptive sliding mode control are 0.4292 mm, 0.5111 mm and 0.1848 mm, respectively. Originality/value The proposed method not only switches continuously, but also the amplitude of the switching signal is adaptive, while maintaining the robustness of the conventional sliding mode control method, which has strong engineering application value.

scholarly journals Finite-Time Synchronization Between Two Different Chaotic Systems by Adaptive Sliding Mode Control

2021 ◽  
Vol 7 ◽  
Author(s):  
Nipaporn Tino ◽  
Piyapong Niamsup
Keyword(s):  
Sliding Mode Control ◽  
Finite Time ◽  
Chaotic Systems ◽  
Control Method ◽  
Sliding Mode ◽  
Tracking Error ◽  
Adaptive Sliding Mode Control ◽  
Terminal Sliding Mode ◽  
Mode Control ◽  
Different Chaotic Systems

The finite-time chaos synchronization between two different chaotic systems with uncertain parameters and external disturbances is studied. A new and improved adaptive fast nonsingular terminal sliding mode control (ANFTSM) has been designed for a fast rate convergence of tracking error to zero in finite time. The effectiveness of the proposed control method is shown in simulation results.

A Robust Adaptive Sliding Mode Control Method for Attitude Control of the Quad-Rotor

2014 ◽  
Vol 852 ◽  
pp. 391-395
Author(s):  
Yong Gao ◽  
Zhao Qing Song ◽  
Xiao Liu
Keyword(s):  
Attitude Control ◽  
Control Method ◽  
Sliding Mode ◽  
Tracking Error ◽  
Robust Adaptive Control ◽  
Adaptive Sliding Mode Control ◽  
Control Law ◽  
Unknown Disturbances ◽  
Robust Adaptive ◽  
Uncertainty Parameters

Quad-rotor is a multi-variable and strong coupling system which has nonlinear and uncertainties. According to the quad-rotor, a dynamic model of attitude which included uncertainty parameters and unknown disturbances was established. The tracking error state was used to design a slide mode surface, and a Lyapunov function which includes slide mode surface and unknown parameter was built. Further more, a robust adaptive control law was designed. At last, the designed control law was simulated, and the results justify the feasibility of the proposed control law.

Adaptive sliding mode repetitive learning control of the upper-limb exoskeleton with unknown dynamics

2021 ◽  
pp. 095965182110087
Author(s):  
Yan Zhang ◽  
Jian Liu ◽  
Yuteng Zhang ◽  
Ying Zhou ◽  
Lingling Chen
Keyword(s):  
Upper Limb ◽  
Control Strategy ◽  
Sliding Mode ◽  
External Disturbance ◽  
Tracking Error ◽  
Learning Control ◽  
Lyapunov Theory ◽  
Adaptive Sliding Mode ◽  
Upper Limb Exoskeleton ◽  
Repetitive Learning

This article proposes a new adaptive sliding mode repetitive learning control strategy. The proposed controller can obtain satisfactory position tracking performance in the presence of unknown dynamics and external disturbance. The unknown dynamics parameters of the exoskeleton system can be estimated via an adaptive algorithm, which is used to design the sliding mode control law. Besides, the periodic external disturbance of the system can be compensated by repetitive learning to reduce the tracking error. The stability of the proposed method is demonstrated rigorous by the Lyapunov theory. Using an upper-limb exoskeleton model, simulation results demonstrate the effectiveness of the control strategy. The proposed method has a better control performance than other methods.

scholarly journals Adaptive sliding mode control with gravity compensation: Application to an upper-limb exoskeleton system

2019 ◽  
Vol 261 ◽  
pp. 06001
Author(s):  
Sana Bembli ◽  
Nahla Khraief Haddad ◽  
Safya Belghith
Keyword(s):  
Upper Limb ◽  
Sliding Mode ◽  
Robustness Analysis ◽  
Stability Study ◽  
Adaptive Sliding Mode Control ◽  
Parametric Uncertainties ◽  
Gravity Compensation ◽  
Adaptive Sliding Mode ◽  
Upper Limb Exoskeleton ◽  
Flexion Extension

This paper presents a robust control algorithm with gravity compensation in presence of parametric uncertainties. The application deals with an upper limb exoskeleton system, aimed for a rehabilitation application. The treated system is an robot with two degrees of freedom acting on the flexion / extension movement of the shoulder and elbow. An adaptive sliding mode algorithm with gravity compensation has been developed to control the upper limb exoskeleton system. A Stability study is realized. Then, a robustness analysis in the presence of parametric uncertainties using Monte Carlo simulation is developed. To prove the performance of the gravity compensation approach, a comparison study is done. Simulation results are presented to highlight the performances and the effectiveness of the proposed controller using gravity compensation.

scholarly journals Command-Filtered Backstepping Integral Sliding Mode Control with Prescribed Performance for Ship Roll Stabilization

2019 ◽  
Vol 9 (20) ◽  
pp. 4288 ◽  
Author(s):  
Zhongjia Jin ◽  
Weiming Zhang ◽  
Sheng Liu ◽  
Min Gu
Keyword(s):  
Sliding Mode Control ◽  
Controller Design ◽  
Sliding Mode ◽  
Tracking Error ◽  
Sea Waves ◽  
Prescribed Performance ◽  
Mode Control ◽  
Ship Roll ◽  
Roll Stabilization ◽  
Differential Expansion

In this paper, a novel, robust fin controller based on the backstepping control strategy and sliding mode control is proposed to handle the problem of ship roll stabilization. First, the mathematical model of the fin control system is established, including the modeling errors and the external disturbances generated by sea waves. In order to address the side effects caused by differential expansion, a command-filter is implemented within the backstepping controller design. By introducing a new performance function and a corresponding error transformation, the compensated tracking error can be bounded to achieve the desired prescribed dynamic and steady-state responses. The sliding mode disturbance rejection control with prescribed performance is realized by combining the disturbance observer. Simulations are presented to demonstrate the effectiveness of the proposed control scheme.

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