Abstract
A four wheel steering (4WS) control strategy is derived and evaluated using a nonlinear vehicle model along with a nonlinear tire model. The vehicle model used is a three degree-of-freedom model. Yaw rate, lateral velocity and longitudinal velocity are considered with the roll effects included in the calculation of the normal loads for each of the four wheels. These normal forces are used in the tire model to calculate the tire forces and moments for each wheel. The results of simulation indicate the potential benefits gained by using 4WS. These benefits include stability and performance at high speeds and maneuverability at low speeds. (A)