An Energy-Regenerative Vehicle Suspension System – Development, Optimization, and Improvement

With the rapid development of hybrid and fully electric vehicles, electromagnetic suspensions have shown great potential for capturing energy while offering high-level ride comfort. The objective of this research was to develop an electromagnetic-based vehicle suspension system that allows for regeneration of road-induced vibration energy and supplies better dynamics control. A small-scale proof-of-concept system consisting of a mass-spring-damper system, ball screw mechanism, and direct current (DC) machine was designed. The vibration energy in the mass-spring-damper system caused vertical motion of sprung mass and the ball screw mechanism to convert the translational motion into rotary motion, which resulted in the generation of back electromotive force of the DC machine. Systematic optimization methodologies were utilized to provide for selective adaption of suspension parameters, such as spring constant (rate) and damping coefficient, according to different road surface conditions, including harmonic and stochastic waveforms. By maximizing the average of power generation or minimizing the root-mean-square of the sprung mass’s absolute acceleration by selecting optimal parameters, the suspension allowed operation in either energy-oriented mode or control-oriented mode. Furthermore, a bandwidth enhancement technique utilizing cubic nonlinearities was demonstrated to improve the energy harvesting capability of the suspension system. A self-powered regenerative Skyhook control strategy was proposed to overcome the trade-off between passive control (insufficient control) and active control (external energy demand) for the suspension system.