Optimization and finite-frequency H_infin; Control of active suspensions in in-wheel motor driven electric ground vehicles

In this paper, the parameter optimization and _H∞ control problem of active suspensions equipped in in-wheel motor driven electric ground vehicles are investigated. In order to better isolate the force transmitted to motor bearing, dynamic vibration absorber (DVA) is installed in the active suspension. Parameters of the vibration isolation modules are also optimized in order to achieve better suspension performances. As the human body is much sensitive to vibrations between 4 and 8 Hz, a finite-frequency state-feedback _H∞ controller is designed to achieve the targeted disturbance attenuation in the concerned frequency range while other performances such as road holding capability and small suspension deflection are also maintained. The performance of the proposed finite-frequency _H∞ controller is compared with that of an entire frequency one, simulation results prove the effectiveness of the proposed control method.