Design of Observer-Controller Combination for Nonholonomic Mobile Robots

Abstract

This paper presents a combined observer-controller for nonholonomic mobile robots with the immeasurable direction angle. To conquer the local stability caused by the dynamic feedback linearization method, an asymptotically global stable velocity control law is proposed by employing Lyapunov method. This control method removes the restriction of dimension of nonlinear system, and the controller design process is simplified by using virtual control inputs and derivable Lyapunov function. Furthermore, the pole placement method is designed to design the control gain scheduling method. Meanwhile, the angle-error observer is adopted to estimate the sine and cosine of orientation angle error by the available position information of mobile robot. The convergence of the controlled robot system is proved by the Lyapunov theory. Simulation and real experiment are implemented to validate the theoretical analysis.