A dual vibration reduction structure-based self-powered active suspension system with PMSM-ball screw actuator via an improved H2/H∞ control

PMSM-ball screw actuator used in active suspensions has a promise of high energy efficiency, large transmission ratio, and compact structure; however, the nonlinear damping and the overlarge equivalent inertial mass of the actuator have impeded development of the active suspension. In this study, a dual vibration reduction structure according to the stiffness and the damping enhancement is proposed to configure a self-powered featured active suspension. First, mechanics and energy regeneration of the proposed actuator are tested based on the varying charge voltage method. Subsequently, the dual vibration reduction structure is developed by adding the extra spring and damper between the unsprung mass and the conventional vibration reduction device. To regulate the proposed active suspension system, an improved H2/H∞ is developed based on a new soft constraint involved objective function to generate the applicable ideal active force via feedforward and feedback linearization modeling. Moreover, the dual vibration reduction structure is optimized through genetic algorithms according to the novel fitness function. Finally, the comparisons are carried out by evaluating the proposed active suspension, the ideal active suspension and the passive suspension. The results demonstrate that the proposed active suspension regulated by the improved H2/H∞ control is self-powered to achieve a near-ideal performance.