Ride Comfort, Road Holding, and Energy Harvesting of a Hydraulic Regenerative Vehicle Suspension

This article presents the suspension performance and the energy harvesting capabilities of a hydraulic regenerative suspension system. A regenerative shock absorber is designed based on a hydraulic transmission mechanism. The proposed regenerative shock absorber is implemented in a quarter-car model to replace the conventional passive damper. The nonlinear damping force of the regenerative shock absorber, which depends on the pressure in the shock absorber chambers, is derived. Using the continuity equation and Kirchhoff’s law, the flow of oil through the valves is described including the oil compressibility. The variation of the check valve opening as a function of pressure difference is also considered in the mathematical modeling. The amount of the harvested power and the efficiency of the regenerative system are introduced to assess the effectiveness of the new suspension system compared to the traditional passive suspension system. Suspension performance indices such as ride comfort and road holding are evaluated for the regenerative suspension to be compared with the performance of the conventional passive suspension system at different speeds. After this, the performance of the regenerative suspension system is studied at different roads with different roughness. The effect of the regenerative shock absorber size on both the suspension performance and the energy harvesting is introduced. The sensitivity of the suspension system to the variation of the external resistance of the regenerative shock absorber is proved. Results showed that the regenerative shock absorber could play a vital role in improving the suspension performance by increasing the ride comfort and improving the road holding in addition to the ability to harvest a portion of the wasted energy in the suspension system.