Performance comparison between electromechanical and electro-hydrostatic regenerative shock absorbers

Abstract

Controllable damping solutions are increasingly finding their way into passenger cars and other vehicles. They improve ride quality by enhancing comfort and handling performance. Semi-active solutions based on controlled valves or variable-rheology fluids are by far the most common technologies in the automotive industry. However, regenerative alternatives that employ electric machines can be seen as a desirable evolution of the suspension market. In this context, the present paper studies two regenerative solutions: electro-hydrostatic and rotary electromechanical dampers. Transmission interfaces are particularly relevant in these technologies. Adequate choices are needed to guarantee proper packaging, performance, structural integrity, and high efficiency. This work compares both technologies in terms of design and packaging. Furthermore, experimental results are analysed to understand the performance of damping solutions. It is demonstrated that the rotary electromechanical device outperforms its electro-hydrostatic counterpart in important features, such as conversion efficiency, envelope, mass and dynamic behaviour.