Gain-Scheduling Control of Vehicle Roll Stiffness Distribution

The influence of lateral load transfer on vehicle´s handling and stability is analyzed via a 3 degree of freedom (3 DOF) vehicle dynamics model. A proper distribution of front and rear roll stiffness to control the lateral load transfer on the front and rear axles can improve the vehicle´s handling and stability obviously. A roll stiffness distribution control scheme is proposed based on gain-scheduling technique, for intense nonlinearity exists between tire and road and a precise mathematical model is difficult to obtain between the roll stiffness controlling and the handling, stability of the vehicle. A PID controller taking a semi-active suspension as the actuator is designed, whose gains can be tuned to adapt the changing of the running condition and an optimal roll stiffness distribution can be obtained. Some simulation results demonstrate that the vehicle handling and stability can be improved efficiently in the linear region of the tire, though it is difficult to bring the vehicle back to stability when the tire has fallen into saturation. So it may be a good method to take roll stiffness control as a complement for the vehicle stability control.