Disturbance Observer-Based Prescribed-Time Tracking Control for Robotic Manipulators with Uncertainties and Disturbances

Abstract

This paper proposes a prescribed-time tracking control scheme combined with a disturbance observer, ensuring prescribed time convergence for n -link rigid robotic manipulators, while considering both internal uncertainties and external disturbances. Initially, we respectively employ a finite-time function and correction terms to facilitate the design of the controller and disturbance observer, guaranteeing convergence of the system within a predetermined time. In order to address the adverse effects of persistent uncertainties, a prescribed-time disturbance observer is constructed to estimate these uncertainties and ensure that the estimation error converges to zero within the predefined time. Furthermore, in conjunction with the disturbance observer, a prescribed-time controller is formulated via backstepping derivation, executed through refining the virtual tracking errors. Utilizing Lyapunov’s direct method, the proposed controller demonstrates outstanding convergence of full-state tracking errors within a predetermined convergence time, irrespective of initial conditions. Finally, the efficacy of the proposed approach is validated through simulations of a two-link robotic manipulator.