Lyapunov-based control system design for trajectory tracking in electrical autonomous vehicles with in-wheel motors

Abstract

In this paper, a hierarchical three-layer control structure is presented for the vehicle’s path following. In the first layer, a Lyapunov-based control law is proposed for determining forces and torque required at the vehicle’s center of gravity that guarantees the convergence of tracking errors. Then, a feasible formulation is developed to distribute the longitudinal and lateral forces of the wheels. Each wheel’s forces are distributed in such a way that prevents saturation of that tire. In the third layer, a robust sliding mode control is developed to determine the driving/braking torques of each wheel. Finally, a co-simulation is performed using Carsim and MATLAB/Simulink to evaluate the performance of the proposed control system. The results show that the proposed algorithm is capable of tracking the desired values of the lateral position, velocity, and yaw angle. The Comparison between the proposed control system and two other studies in two different paths including lane-change and two-turn path close to the vehicle’s handling limit is carried out. Our proposed method shows more promising results in terms of root mean square of error criterion than the other two methods. In addition, the proposed controller is able to provide the actuator commands of each wheel properly, despite the parametric uncertainties.