Observer-Based Prescribed Performance Adaptive Terminal Sliding Mode Control for Path Tracking of Autonomous Ground Vehicles

This paper investigates the path tracking control problem of the autonomous ground vehicles with the prescribed performance in the presence of the system uncertainties. An observer-based prescribed performance adaptive terminal sliding mode controller is developed. Firstly, considering the parameter uncertainties and unknown external disturbances, the vehicle kinematics model and the 2-DOF vehicle dynamics model are established. Then, a novel finite-time extended state observer is first designed to observe the unmeasured states and the lumped disturbances of the lateral motion control system simultaneously, which can achieve finite-time convergence of the estimated errors. On this basis, to further improve the transient and steady-state performance of the path tracking of the autonomous ground vehicles, a robust path tracking controller is presented based on the adaptive fast nonsingular terminal sliding mode control and the prescribed performance control. It is demonstrated that the path tracking errors can reach the origin in finite time and have the predefined maximum overshoots and steady-state errors. The joint simulation results of MATLAB and CarSim show that the newly proposed control algorithm can realize the precise path tracking control of the autonomous ground vehicles, keep the tracking errors within the prescribed bounds, and has strong robustness.