For optimization of performances of a hydraulic-electricity energy regenerative suspension (HERS) unit, the tradeoff point was determined based on study of ride comfort and energy-regenerative characteristics of a HERS unit in this study. A HERS unit as a new energy reclaiming suspension device is equipped with an energy-harvesting hydraulic electromagnetic shock absorber (HESA). The HESA together with a quarter car was modeled based on theoretical analysis and experiments, in which the root mean square (RMS) values of the sprung mass vibration acceleration and the recovered power are regarded as the optimization objectives under different road excitation conditions such as the constraints (natural frequency, dynamic displacement, and dynamic load of wheels). The HERS unit was optimized after the relationship between the ride comfort and the energy regeneration was obtained. In comparison with the traditional suspension, the HERS unit may be utilized to improve the ride comfort and meet the vehicle-driving requirements. Moreover, the total input power may be saved by 34-100 W on average while the vibration acceleration is among 0.65-1.06 m/s2. Furthermore, it is verified that the HERS damping force control is the feasible under various load currents
