Research on Damping Noncoincidence and Its Influence Factors of Multibranch Hydropneumatic Suspension

Multibranch interconnected hydropneumatic suspension (MIHS) is increasingly applied in heavy multiaxle vehicle (HMV) for its superior characteristics, such as adjustable damping, and the antiroll and balancing axle load ability. However, as for multibranch hydropneumatic suspension, the stiffness and damping are coupled with each other tightly, which represents damping noncoincidence (DNC) problem. The DNC problem has become a key obstacle for developing suspension control technology and improving suspension performance. Firstly, a kind of MIHS structure is developed for an HMV, and the interconnected structure and principle are explained. Then the DNC problem is proposed and is given a description. And then, according to the researching needs, the suspension system model of single cylinder connected with multiple branches is built up based on the knowledge of state change of fluid and gas. Fourthly, the root cause of DNC problem is given according to simulation results. Fifthly, the impacts of three factors on DNC problem are studied, respectively, by adjusting excitation signal and system parameters in the simulation. The simulation results are quantitatively compared with regard to damping noncoincidence rate (DNCR). In the end, some conclusions are drawn based on the discussion and analysis and the future work is proposed.