Adaptive tracking control design for high-order nonholonomic mobile robot systems

Backstepping based tracking control designs for an uncertain mobile robot system with nonholonomic constraints are presented. Due to the necessity of the repeated differentiation of the virtual controller in the kinematic back stepping design stage, high-degree polynomial of the affine functions are generally included in many existing schemes. That unfortunately would cause the possible blowup of the actuators for high-order kinematic systems (e.g., a trailer type mobile robot) in high-speed motions. Regarding this, an exponentially modulated linear control function is included in this design to alleviate such a difficulty. Next at the dynamic design level, an adaptive control algorithm is developed for attaining the global asymptotic tracking stability of the overall closed-loop system. Simulation results on a unicycle wheeled mobile robot is given in the final to demonstrate the effectiveness of the proposed design.