Adaptive sliding mode control strategy based on disturbance observer and neural network for lower limb rehabilitative robot

Abstract In this study, to achieve accurate tracking of the desired trajectory during passive control of the lower limb rehabilitation robot, an adaptive sliding mode controller based on disturbance observer and radial basis function neural network (RBFNN) is proposed for the lower limb rehabilitati...

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Main Authors: Yihang Ma, Jirong Wang, Qianying Li, Lianwen Shi, Yunhao Qin, Huabo Liu, Hongzhi Tian
Format: Article
Language:English
Published: Wiley 2023-03-01
Series:IET Control Theory & Applications
Online Access:https://doi.org/10.1049/cth2.12371
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author Yihang Ma
Jirong Wang
Qianying Li
Lianwen Shi
Yunhao Qin
Huabo Liu
Hongzhi Tian
author_facet Yihang Ma
Jirong Wang
Qianying Li
Lianwen Shi
Yunhao Qin
Huabo Liu
Hongzhi Tian
author_sort Yihang Ma
collection DOAJ
description Abstract In this study, to achieve accurate tracking of the desired trajectory during passive control of the lower limb rehabilitation robot, an adaptive sliding mode controller based on disturbance observer and radial basis function neural network (RBFNN) is proposed for the lower limb rehabilitative robot in the presence of uncertain parameters and external bounded disturbances. First, the Euler–Lagrange dynamic model of the lower limb rehabilitative robot is described. Second, a sliding mode controller is designed to stabilize the system with an improved sliding mode reach rate under the assumption that all parameters of the dynamics model are known. To achieve a sliding mode controller without the above assumptions, the proposed adaptive RBFNN and the disturbance observers are employed to compensate for disturbances and the uncertainties in the robot's dynamic mode via feedforward loops. The Lyapunov stability theory is used to prove that the proposed controller has accomplished a significant control effect with excellent performance and the output tracking error can be converted to a very small neighborhood through reasonable design parameters. Finally, the performance of the controller based on the state feedback and state observer are demonstrated by numerical simulations, respectively.
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spelling doaj.art-78ebf21bc6fa4210b54b0854b11c99452023-03-02T05:58:24ZengWileyIET Control Theory & Applications1751-86441751-86522023-03-0117438139910.1049/cth2.12371Adaptive sliding mode control strategy based on disturbance observer and neural network for lower limb rehabilitative robotYihang Ma0Jirong Wang1Qianying Li2Lianwen Shi3Yunhao Qin4Huabo Liu5Hongzhi Tian6College of Mechanical and Electrical Engineering Qingdao University Qingdao Shandong ChinaCollege of Mechanical and Electrical Engineering Qingdao University Qingdao Shandong ChinaShanghai Jiao Tong University Shanghai ChinaCollege of Mechanical and Electrical Engineering Qingdao University Qingdao Shandong ChinaShanghai Sixth People's Hospital Affiliated to Shanghai Jiaotong University School of Medicine Shanghai ChinaSchool of Automation Qingdao University Qingdao Shandong ChinaCollege of Mechanical and Electrical Engineering Qingdao University Qingdao Shandong ChinaAbstract In this study, to achieve accurate tracking of the desired trajectory during passive control of the lower limb rehabilitation robot, an adaptive sliding mode controller based on disturbance observer and radial basis function neural network (RBFNN) is proposed for the lower limb rehabilitative robot in the presence of uncertain parameters and external bounded disturbances. First, the Euler–Lagrange dynamic model of the lower limb rehabilitative robot is described. Second, a sliding mode controller is designed to stabilize the system with an improved sliding mode reach rate under the assumption that all parameters of the dynamics model are known. To achieve a sliding mode controller without the above assumptions, the proposed adaptive RBFNN and the disturbance observers are employed to compensate for disturbances and the uncertainties in the robot's dynamic mode via feedforward loops. The Lyapunov stability theory is used to prove that the proposed controller has accomplished a significant control effect with excellent performance and the output tracking error can be converted to a very small neighborhood through reasonable design parameters. Finally, the performance of the controller based on the state feedback and state observer are demonstrated by numerical simulations, respectively.https://doi.org/10.1049/cth2.12371
spellingShingle Yihang Ma
Jirong Wang
Qianying Li
Lianwen Shi
Yunhao Qin
Huabo Liu
Hongzhi Tian
Adaptive sliding mode control strategy based on disturbance observer and neural network for lower limb rehabilitative robot
IET Control Theory & Applications
title Adaptive sliding mode control strategy based on disturbance observer and neural network for lower limb rehabilitative robot
title_full Adaptive sliding mode control strategy based on disturbance observer and neural network for lower limb rehabilitative robot
title_fullStr Adaptive sliding mode control strategy based on disturbance observer and neural network for lower limb rehabilitative robot
title_full_unstemmed Adaptive sliding mode control strategy based on disturbance observer and neural network for lower limb rehabilitative robot
title_short Adaptive sliding mode control strategy based on disturbance observer and neural network for lower limb rehabilitative robot
title_sort adaptive sliding mode control strategy based on disturbance observer and neural network for lower limb rehabilitative robot
url https://doi.org/10.1049/cth2.12371
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