Simulation Of Nonlinear Characteristic Of Ydro-pneumatic Suspension Of Heavy Vehicles

Hydro-pneumatic suspension is a new type suspension system with hydraulic oil transfer pressure and with inert gas (generally nitrogen) as the elastic medium, which integrates elastic elements and the damping device. With its excellent non-linear characteristics and damping performance, it can meet the requirements of the heavy vehicle ride and handling stability to the utmost.This thesis takes gas chamber hydro-pneumatic suspension of heavy vehicles as the research object, and introduces the structure and operating principle, and describes in detail the functions and characteristics, and briefly describes the balance design of hydro-pneumatic suspension system. The nonlinear mathematical model is established based on the structure. The simulation model is built on MATLAB/Simulink module, and simulated with different input signal, and then output the relationship between the force and displacement/velocity. The force variation was compared and the variation of the suspension characteristics was analyzed by changing the structural parameters (orifice area, the initial value of the accumulator) of hydro-pneumatic suspension. The elastic force and damping force mathematical models of hydro-pneumatic suspension system are established in the paper, and then the nonlinear stiffness and nonlinear damping are simulated. The influence is researched and summarized, which is the structural parameters (orifice area, the initial value of the accumulator) and operating parameters (excitation signal, suspended mass) on the stiffness and damping characteristics.According to the nonlinear characteristics of hydro-pneumatic suspension system, the single round and two degrees of freedom nonlinear dynamic model is established, which is based on the random road incentive. The time signal curves of the body acceleration, suspension travel and relative dynamic wheel load are got from the simulation model. Analysis of different road surface incentive effects on the vehicle ride comfort, which is based on the ride comfort assessment index. The structure parameters (orifice area, the initial value of the accumulator) influenced on the ride comfort is also studied.The thesis describes the structure and working principle of the adjustable damping valve, and obtains the flow area and flow characteristics by the formula. The feature of adjustable flow area is of great significance to hydro-pneumatic suspension system...