LIU S B, LI Z, ZHANG Z Y,et al. Fixed-time parameter-varying sliding synchronous control of manipulators with actuator faults and nonlinearities[J].Journal of Henan Polytechnic University(Natural Science) ,2025,44(6):172-181.

doi:10.16186/j.cnki.1673-9787.2023120054

Received: 2023/12/19

Revised: 2024/04/10

Published: 2025/10/14

Fixed-time parameter-varying sliding synchronous control of manipulators with actuator faults and nonlinearities

Liu Shubo1,2, Li Zhi1,2, Zhang Zhiyuan1,2, Luo Xianxi1,2

1.Jiangxi Industrial Technology Research Institute of Rehabilitation Assistance， East China University of Technology， Nanchang  330013， Jiangxi， China；2.School of Mechanical and Electronic Engineering， East China University of Technology， Nanchang  330013， Jiangxi， China

Abstract: Objectives It is needed to attenuate the adverse effects caused by unknown actuator nonlinearities， actuator faults， and bounded disturbances， and to achieve fast and high-precision tracking of the desired trajectory of manipulator. Methods A fixed-time parameter-varying sliding fault tolerant synchronous control（FPS-FTSC） strategy was proposed based on the sum-of-squares（SOS） theory for a class of uncertain manipulator systems. Firstly， a unified mathematical model of actuators with unknown nonlinearity and faults was established. Secondly， a synchronous error control term was introduced to ensure the coordination between the various axes of manipulators， and it was combined with the prescribed performance function（PPF） to complete error transformation. With the parameter-varying terminal sliding framework， it was demonstrated that synchronous error and position tracking error could converge to the range limited by PPF within a fixed time based on Lyapunov stability theory. Then， while solving for the gain of parameter-varying controller， the conditions for the existence of global optimal H_∞ disturbance suppression performance of the system were given. Results In simulation and experiment， the FPS-FTSC strategy enabled both position tracking error and synchronization error to quickly converge to a small neighborhood of zero under ideal conditions without actuator faults and nonlinearity； In the presence of various actuator faults and nonlinearity， the proposed strategy could still achieve fast and stable tracking of the desired trajectory， and had better control performance than existing algorithms. Conclusions Simulation and experimental results showed that the proposed control strategy could achieve good transient and steady-state performance of the system under multiple constraints， demonstrating good robustness and fault tolerance.

Key words: manipulator; actuator fault; parameter-varying sliding synchronous control; fixed-time fault-tolerant control; actuator nonlinearity