Force control of a 4WS4WD vehicle for path tracking

The aim of this paper is to develop a system where forces at the wheels of a ground vehicle are controlled to guide the vehicle along a planned path. The 7-order Bézier curves are applied to path planning and online path tracking, and used to obtain profiles of velocities and accelerations for the guidance of a 4WS4WD vehicle. The dynamic model used for force control is developed for the determination of the reference forces and steering angles at four wheels. The motion profiles obtained using the continuously updated Bézier segments are then applied to control the driving and steering motions of individual wheels. Note that this control methodology does not address the closed loop path tracking control, instead it only demonstrates the resilience of an open loop system through a vehicle design which only requires a dynamic model where the number of uncertain parameters are minimized. In future work, complementary steering control inputs will be generated through close loop path tracking control. Simulation results are provided to validate the proposed methodology.