Fixed-Time Generalized VGESO-Based Trajectory Tracking Control for WMRs on Uneven Road: A Fully Actuated System Approach

Abstract

In this paper, a trajectory tracking control problem is investigated for a wheeled mobile robot (WMR) on uneven road. A mapping relationship is established between the velocity and position to describe the motion of the robot on uneven road. An adaptive kinematic controller (AKC) is designed to improve the trajectory tracking accuracy, where robot parameters and control gains are both estimated. Then, a fixed-time generalized variable gain extended state observer (VGESO) is proposed to estimate the states and disturbance caused by uneven road, where a balance is maintained between disturbance rejection and noise suppression. Next, a dynamic controller is put forward by combining fully actuated system (FAS) approach with practical prescribed time (PPT) control. It is analyzed that the velocity tracking error system is PPT stable. Finally, experimental results demonstrate effectiveness and superiority of the proposed method.