A Novel Fast Fixed-Time Control for Robotic Manipulator Based on Disturbance Observer

This paper studies the problem of trajectory tracking control for robotic manipulators subject to model uncertainties, external disturbance and actuator saturation. At first, a nonsingular fixed-time sliding mode variable is developed based on a novel fixed-time stable system, which solves the singularity problem brought by the terminal sliding mode control and obtains a fast convergence rate. After that, a novel fixed-time sliding mode observer is designed to estimate and compensate the model uncertainties and external disturbance. The fixed-time stability of the system under the proposed composite control is proved by Lyapunov stability theory. Finally, the effectiveness of the method is verified by comparative simulation.