Adaptive and sliding mode tracking control for wheeled mobile robots with unknown visual parameters

Abstract

The trajectory tracking control problem of dynamic nonholonomic wheeled mobile robots is considered via visual servoing feedback. A novel visual feedback tracking error model is proposed. Its tracking controller is independent of uncalibrated visual parameters by using new methods. This controller consists of two units: one is an adaptive control for compensation of the uncertainties of dynamic parameters, the other is a variable structure control for the interference suppression. In addition, the torque tracking controller is global and smooth, and the chattering phenomenon is eliminated. The asymptotic convergence of tracking errors to equilibrium point is rigorously proved by the Lyapunov method. Simulation and experiment results are provided to illustrate the performance of the control law.