Coordinated control of active tire lateral forces and roll centre height via active camber

Abstract

Active camber suspensions (ACS) can adjust wheel cambers by actively altering suspension geometry, showing great potential for improving vehicle dynamics. The active adjustment of suspension geometry will lead to much larger variations of vehicle roll centre height (RCH), which should be considered for vehicle dynamics. In this paper, the coordinated control methodology of active tire forces and roll centre height (CCM–ATF–RCH) via active camber of rear multi-link suspension is proposed to improve vehicle lateral dynamics. To explicitly exploit the coupling between camber and roll centre height, the kinematic characteristics of the multi-link active camber suspension (MACS) are embedded in both an eight-degrees-of-freedom (8-DOF) plant model and a 3-DOF control-oriented reference model. On this basis, the MPC-based coordinated controller is developed that dynamically updates vehicle parameters, including RCH, and allocates rear wheel camber to balance lateral force generation and roll stability under actuator and camber constraints. Simulation results demonstrate that the proposed CCM–ATF–RCH can adjust tire lateral forces and increase vehicle roll centre height simultaneously via cambering the wheel. Under a 60° step steer at 90 km/h ( $\mu$  = 0.85), the proposed CCM–ATF–RCH reduces the peak roll angle, yaw rate, and sideslip angle by 7.91%, 4.31%, and 12.37% compared with RCH-fixed active camber control. In a 108 km/h double lane change, it lowers the peak roll angle by about 7.6% while keeping similar yaw rate and side slip responses and the rear tires further from their friction limits, highlighting improved roll stability without loss of handling performance.