Fixed-time Trajectory Tracking Control for Pneumatic Multi-DOF Manipulator System with Unknown Disturbances

In this paper, a novel fixed-time control scheme is developed to obtain desired trajectory tracking control performances for the pneumatic multi-degrees of freedom (DOF) manipulator system driven by pneumatic muscles (PMs). A fixed-time disturbance observer (FTDO) is proposed to estimate unknown disturbances in the pneumatic multi-DOF manipulator system, and estimation errors converge into the bounded region effectively in fixed-time. Moreover, a fixed-time dynamic surface controller (FTDSC) is designed to improve trajectory tracking control performances, and the pneumatic multi-DOF manipulator system is proven to be uniformly ultimately fixed-time bounded stable by Lyapunov analysis. Finally, comparative simulations are presented to demonstrate the effectiveness of the proposed control approach.