Fixed-Time Tracking Control of Wheel Mobile Robot in Slipping and Skidding Conditions

This work develops a fixed-time control scheme to address the tracking control problem for a wheeled mobile robot (WMR) in lumped disturbance conditions involving slipping, skidding, and external disturbances. A novel fixed-time velocity control law is first developed for the error kinematics of the WMR system based on an intermediate-term design. To ensure high-performance tracking for the generated velocity in lumped disturbance cases, the impacts of slipping and skidding are incorporated into the dynamics of the WMR system. A fixed-time trajectory tracking control law that integrates a fast fixed-time disturbance observer is also proposed. Specifically, the well-designed observer is developed to estimate the lumped disturbances. The proposed control scheme avoids the commonly existing singular problem and ensures that the error states of WMR can converge into a neighborhood of the origin within a fixed time during slipping and skidding. Based on comparison experiments, the proposed control scheme exhibits superior performance and effectiveness.