Vehicle lateral velocity and yaw rate control with two independent control inputs

Vehicle cornering stability and stable handling are important both from the viewpoints of safety and passenger comfort. To attain superior stability and maneuverability, it is desired that the vehicle system can control lateral velocity and yaw rate at any desired values simultaneously. This requires at least one additional control input, which is independent of the front steering angle. This paper explores the use of the differential torqute (force) between two front wheels, that of two rear wheels, and the rear steering augle as a second control input. The analysis utilizes a linearized vehicle model for lateral and yaw motions. A control algorithm with two independent control inputs, which features gain scheduling mechanism, is presented. Performance evaluation is based on a simulation study on a nonlinear vehicle model and an experimental study with a four wheel steering and four wheel drive laboratory model vehicle.