Abstract
In order to compensate the drawbacks of individually equipped DYC and 4WS subsystems, a chassis control integration structure based on main-loop and servo-loop is proposed. In the main-loop, a sliding mode controller is designed to obtain the desired longitudinal, lateral forces and stabilizing yaw moment of the vehicle. In the servo-loop, for optimally distributing the forces and moment among wheels, a nonlinear sequential quadratic programming approach is adopted to get appropriate target slip ratios and slip angles, and ultimately compute the optimal control inputs, i.e. wheel control torques and active steering angles. Simulation results indicate that significant improvement in vehicle handling performance and stability margin can be expected from the proposed integration structure.
Keywords: Vehicle dynamics, integrated vehicle control, four wheel steering, direct yaw moment control, tyre nonlinearities