Abstract
KEYWORDS –Semi-active suspension; Vehicle lateral stability; Variable stiffness and damping; Roll moment distribution; Nonlinear controller
ABSTRACT –
Existing control schemes distribute damping forces between front and rear axles through semi-active suspension (SAS). However, these control schemes lack a theoretical foundation. Given that a new variable stiffness and damping system configuration may only require adjusting the damping force of a variable damper, this study considers an ordinary magnetorheological damper (MRD) SAS (including tires) as a variable stiffness and variable damping suspension system. The configuration of the SAS does not need any modifications. A novel control strategy is presented to control the stiffness of suspension to distribute the roll moment between the front and rear axles. This strategy considers the minimization of body accelerations in three directions as well as the neutral steer as the control target. A nonlinear controller for the roll moment distribution and three fuzzy controllers for the control of the vehicle body attitude are designed. The roll moment distribution coefficient is combined with three output control forces from the fuzzy controllers. Through a decoupling arithmetic, the control forces in three directions are decoupled into four control forces generated by four MRDs. Simulation results demonstrate that the proposed control strategy can achieve both favorable handling stability and ride comfort.