Smooth robust tracking controllers for uncertain robot manipulators

Two smooth robust tracking controllers for uncertain robot manipulators are presented. The controllers yield smooth acceleration response. A deterministic approach is adopted in developing the controllers. The Lyapunov direct method is used, and a nonlinear Lyapunov function is employed to prove the stability of the system. The first controller is shown to render the closed-loop system practically stable, forcing the state tracking error to converge exponentially to a small neighborhood of the origin. The second controller is shown to render the closed-loop system asymptotically stable, forcing the state tracking error to converge to the origin. The efficacy of the controllers is verified by application to a planar two-link manipulator