Design of active and energy-regenerative controllers for DC-motor-based suspension

In this paper, active and energy-regenerative controllers are designed for the DC-motor-based suspension, which is able to operate in two modes: active control for ride comfort promotion and energy-regenerative control for energy harvesting. In order to achieve these two modes, the main/torque-tracking loop control structure is presented in this paper. Then by simplifying torque-tracking loop, working areas of the DC-motor actuator are analyzed. As for main loop controller design, H∞ robust control is investigated for the active suspension based on a full-car suspension model. The restricted H∞ controller, which is the combination of proposed H∞ controller and a restriction strategy that confines the motor to the working areas of energy regeneration, is employed as the main controller to realize energy regeneration. Simulations are carried out with random uneven road inputs and the results demonstrate that better ride comfort can be achieved by proposed active suspension and energy-regenerative (ER) suspension compared with passive counterpart. Moreover, effects of uncertainties are also investigated under several cases, indicating good robustness of designed suspension systems. Meanwhile, capacity of energy regeneration is also ensured by the ER suspension.