Rotary regenerative shock absorbers for automotive suspensions

The increasingly strict limits on pollutant emissions are pushing the car industry towards the electrification of the powertrain and chassis. This scenario has driven the automotive field to the use of energy harvesters. Among these, regenerative shock absorbers are mechatronic devices that enable the energy recovery from road irregularities, thus yielding benefits in terms of fuel saving and ride quality. The state of the art proposes different technologies for regenerative dampers. In this context, rotary dampers represent an unexplored field from the scientific point of view. These devices feature a linkage and a gearbox to convert the suspension linear motion into rotation of an electric machine. This work proposes a novel system-level design methodology for rotary regenerative shock absorbers and explores their performance from an experimental perspective. The design is focused in yielding a compact solution able to fulfill a given damping specification. Hence, the integrated definition of electric machine, gearbox and linkage is addressed by the proposed method. To support the methodology, a case study is presented. A fully functional prototype is produced and successfully validated in terms of damping capability, total conversion efficiency and acoustic behavior. The obtained results demonstrate the validity of the proposed methodology and the advantageous features of rotary dampers with respect to other regenerative suspension solutions. •Regenerative shock absorbers allow recovering energy from road unevenness.•We propose a rotary damper with a lever, a gearbox and an electric machine.•A system-level method drives the design of electric machine and transmission.•A prototype is built and tested in terms of damping, efficiency and noise.