The net power control of hydraulic-electricity energy regenerative suspension

For achieving the control of hydraulic-electricity energy regenerative suspension (HERS), a novel control algorithm, net power control (NPC), is applied in this study. A HERS unit as a new energy reclaiming suspension device is equipped with an energy-harvesting hydraulic-electricity shock absorber (HESA). The composition and classification of HESA damping force were analyzed based on the basic working principle of HESA. Thus, the mathematical model of HESA damping force is deduced as a function of suspension dynamic speed and load current. A series of experiments were made to verify the reliability of the model. Based on the energy flow analysis of the suspension system, the net power flowing into the suspension is calculated. In order to minimize the vibration acceleration of the vehicle body, a novel net power control is proposed. The comparison result indicates the control effect of NPC is more significant than skyhook control, especially in the high excitation frequency. Also, the HERS bench test was carried out to verify the feasibility of NPC. The related results show that the maximum acceleration of the vibration is improved by 34.23 % with NPC on bump pavement excitation. And on B-class random road, the root mean square (RMS) value of the sprung mass vibration acceleration is reduced by 65 %. Furthermore, the influence of suspension dynamic velocity and deflection on the optimal control load current is obtained.