Adaptive super‐twisting algorithm‐based fractional‐order sliding mode control of redundantly actuated cable driving parallel robot with uncertainty and disturbance estimation

Abstract

This paper proposed an adaptive super-twisting (AST)-based fractional-order sliding mode control algorithm under disturbances for redundantly actuated cable driving parallel robots. A novel fractional-order non-singular fast terminal sliding mode surface is constructed, and the fast response convergence and accuracy tracking performance can be obtained in the sliding mode phase; meanwhile, an auxiliary system is designed to overcome the adverse effects of the input saturation. Then, to compensate for the model uncertainty and external disturbances, the uncertainty and disturbance estimation is designed, and a novel AST algorithm is developed to suppress the estimation error without the known bound of the adaptive gains and guarantee the finite-time convergence in the reaching phase. The Lyapunov stability theory is employed to prove the convergence of the proposed controller. Finally, numerical simulations are conducted in the commercial software of MATLAB/SIMULINK to demonstrate the effectiveness of the proposed controller.