A simple linear stabilizing controller for a RLED robot with uncertain parameters and some related applications

Abstract

This study considers the stability problem of a rigid-link electrically driven (RLED) robot manipulator with uncertain parameters and unknown payload. We present a simple controller which ensures local exponential stability of the equilibrium point when the dynamics of the mechanical system as well as the electrical effects of the actuators are included in the model. As far as the mechanical system is concerned we assume that only bounds on the unknown parameters are available. In particular, a precise prior knowledge of the gravity force at the desired equilibrium point is not required. The proposed controller is linear and can easily be implemented. We demonstrate how the controller can be integrated in a global strategy that ensures the convergence of the system from any given initial condition to any selected set-point. We consider some possible applications with respect to issues like the stability of the system when vanishing and nonvanishing perturbation terms are included in the model, and small-signal finite-gain Lp stability.