An investigation into unified chassis control scheme for optimised vehicle stability and manoeuvrability

Abstract

This paper describes a unified chassis control (UCC) strategy to improve the lateral stability andmanoeuvrability of vehicles by integrating individual chassis control modules such as electronic stability control (ESC), active front steering (AFS) and continuous damping control (CDC). In order to achieve a target lateral vehicle response, an integrated AFS and four individual wheel braking controls have been used for an optimum distribution of longitudinal and lateral tyre forces the desired yaw moment for lateral stability has been designed by the sliding control method using a planar bicycle model and taking into consideration cornering stiffness uncertainties. The desired yaw moment is generated by the coordinated control of AFS and ESC. Optimal coordination of the control authority for the AFS and the ESC has been determined to minimise longitudinal deceleration. Estimated vertical tyre forces have been used for the optimum distribution of the longitudinal and lateral tyre forces. For the improved performance of the lateral stability control system, the damping forces at the four corners have been controlled to minimise roll angle by the CDC system. The response of the vehicle to the UCC system has been evaluated via computer simulations using vehicle dynamic software CarSim and a UCC controller coded with Matlab/Simulink. Computer simulations of a closed-loop driver–vehicle–controller system subjected to double lane change have been carried out to prove the improved performance of the proposed UCC strategy over a conventional ESC.