Multi-objective H ∞ optimal control for four-wheel steering vehicle based on yaw rate tracking

In this paper, a lateral controller is designed for four-wheel steering (4WS) vehicles. The linear lateral dynamics of 4WS vehicles are deduced and then analysed, aided with three-dimensional graphs. To improve vehicle handling and stability at high speed, a multiobjective H ∞ optimal control algorithm is presented, while yaw rate is the only feedback signal. Simulation shows that the sideslip angle, yaw rate, and lateral acceleration of the 4WS vehicle follow and maintain preferable characteristics. The 4WS vehicle is agile and consistent with the steering input and does not understeer excessively.