A variable structure control system for a 6 dof puma 560 robot manipulator

Abstract

This paper deals with the application of a variable structure observer developed for a class of nonlinear systems to solve the trajectory tracking problem for rigid robot manipulators. The considered observer design approach proposes a simple design methodology for systems having completely observable linear parts and bounded nonlinearities and/or uncertainties. The considered observer is basically the conventional Luenberger observer with an additional switching term that is used to guarantee robustness against modeling errors and system uncertainties. We propose to modify this observer structure and use the system nonlinearities in the observer structure under the Lipschitz condition. To solve the tracking problem, we have used a control law developed for robot manipulators in the full information case. The closed loop system is shown to be globally asymptotically stable based on Lyapunov arguments. Simulation results on a six D-O-F robot manipulator show the asymptotic convergence of the observation and tracking error vectors