Hydraulic regenerative braking system studies based on a nonlinear dynamic model of a full vehicle

To obtain a reasonable match of the main parameters of a hydraulic regenerative braking system and to improve the energy recovery efficiency, this paper establishes the corresponding mathematical models and testbed for a hydraulic regenerative braking system. The proposed system is analysed and verified through simulation and experiments. Then, the linear and nonlinear mathematical models of a full vehicle are built, with joint simulation of the hydraulic regenerative braking system, and the influence of the hydraulic regenerative braking system on braking performance under different running conditions is discussed. The results indicate that the deviations in the simulation results between the linear and nonlinear dynamic models are very small. When the brake deceleration and road adhesion coefficient are 0.2, deviations are within 1.38 %. With an increase in the braking deceleration and road adhesion coefficient, the deviations in braking time and distance between the systems become larger and larger. When the braking deceleration and road adhesion coefficient are 0.7, the deviation reaches 30 %. Finally, with braking energy recovery efficiency and braking distance as the optimization objectives, the nonlinear braking energy recovery system parameters are optimized. After optimization, the energy recovery efficiency of the nonlinear system reaches 76.3 %, and the braking distance is 22.8 m.