Effects of integrated control of active four wheel steering and individual wheel torque on vehicle handling and stability - A comparison of alternative control strategies

This paper investigates the effectiveness of several different combinations of control inputs for improvement of vehicle handling and stability. Three combinations of control inputs are considered in this paper; namely, (1) rear wheel steering control with conventional front wheel steering and standard brake system, (2) four wheel torque control plus conventional front wheel steering, (3) front and rear wheel steering control plus four wheel torque control. The focus of this investigation is to clarify the relative merit of the different control strategies to accomplish a given task. The theory for nonlinear predictive control was extended to take into account partially given input and applied to the design of the control system. Simulations of braking combined with steering and braking under mu-split condition indicate that the integrated control of four wheel steering and individual wheel torque control results in a vehicle that can maintain directional control and stability.