Extended nicosia-tomei observer-based tracking control of robot manipulators

This paper presents an observer-based control of robot manipulators for velocity estimation and trajectory tracking. The proposed scheme does not require the velocity feedback because velocity measurements may not be available due to cost and weight. We introduce parameters involving the tracking and estimation errors and their derivatives into the observer-controller. Exploiting the structural properties, we propose the new combined form of observer-controller to ensure the closed loop stability of the tracking and estimation. Moreover, we show that the proposed controller-observer scheme achieves semi-globally exponential stability results for tracking errors and estimation errors. The proposed observer-controller facilitates the stability analysis and explicitly extends Nicosia-Tomei observer-based tracking control. To validate the proposed scheme, we conduct numerical simulation of a two-link robot. The simulation results clearly indicate that the proposed scheme improves the error convergence for both trajectory tracking and velocity estimation.