Model Reference Tracking Control of A 4WS Vehicle Using Single and Dual Steering Strategies

Control schemes and strategies of a 4WS vehicle are studied, where schemes are single and dual steering and strategies are zero side slip (ZSS), zero yaw rate (ZYR) and model reference tracking. While Single steering scheme controls only the front steering angle of vehicle, dual steering controls both rear and front steering angles independently. A special model reference tracker, which smoothes vehicle transient response and yields the same steady state yaw behavior as 2WS vehicle, is finally proposed. The dynamic models are a 2DOF linear handling model for controller and a 3DOF nonlinear handling model with CALSPAN tire coefficients for simulation.

Simulation results show that while dual steering scheme can effectively control yaw rate and lateral velocity references, single steering scheme is not able to track both of the mentioned variables. It is also shown that the proposed reference is able to improve the handling properties of vehicle.