Fixed-time parameter-varying sliding synchronous control of manipulators with actuator faults and nonlinearities
Liu Shubo
Li Zhi
Zhang Zhiyuan
Luo Xianxi
Abstract：Objectives It is needed to attenuate the adverse effects caused by unknown actuator nonlineari-ties,actuator faults,and bounded disturbances,and to achieve fast and high-precision tracking of the de-sired 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 coordina-tion between the various axes of manipulators,and it was combined with the prescribed performance func-tion(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 perfor-mance 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 re-sults 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.
Keywords：manipulatoractuator faultparameter-varying sliding synchronous controlfixed-time fault-tolerant controlactuator nonlinearity
Publication Date：2025-11-30
Online Publishing Date：2025-10-22(First online date of this platform, not the publication date of the document)
Pages：10( 172-181 )