Adaptive-observer-based dynamic surface tracking of a class of mobile robots with nonlinear dynamics considering unknown wheel slippage

摘要

This paper addresses an adaptive-observer-based control design problem for path tracking of a class of wheeled mobile robots in the presence of unknown slippage effects. The linear and angular velocities of mobile robots are assumed to be unmeasurable. This causes nonlinear coupling terms between the unmeasurable velocities and unknown skidding and slipping effects in the robot dynamics, making the design of an adaptive observer difficult. An adaptive observer is presented to estimate unmeasured velocities of the mobile robots and to compensate for the skidding and slipping effects. Then, a simple adaptive controller at the dynamic level is derived using dynamic surface design methodology. Fuzzy logic systems are employed to overcome the coupling problems between the unmeasurable velocities and unknown skidding and slipping effects in the controller design procedure. From Lyapunov stability analysis, the stability of the controlled closed-loop system is analyzed under slippage conditions.