| Vehicles are an important vehicle for people to travel and carry goods daily.Hydro-pneumatic suspension systems can effectively reduce the vibration of moving vehicles and help to improve the ride comfort and handling stability of vehicles.The construction of the oil-gas spring is simple,the high-pressure inert gas is used as the elastic medium and the hydraulic oil is used as the conductive force medium.Hydro-pneumatic springs make the suspension system of hydro-pneumatic suspensions have strong non-linear stiffness and non-linear damping characteristics,which improves the suspension's ability to absorb vibration.Hydro-pneumatic suspension nonlinear stiffness characteristics can adapt to the vehicle load changes,and the nonlinear damping characteristics can well buffer the body vibration.The stiffness and damping of the hydro-pneumatic suspension are well-designed,and the system stiffness can be changed by adjusting the air pressure in the air chamber,and the height of the vehicle body can also be adjusted by charging and discharging the oil-gas spring.Therefore,it is of great significance to study the influence of the parameters of the hydro-pneumatic suspension system on the vibration characteristics of the vehicle.Firstly,this paper introduces the structure and working principle of the oil-air spring.Combining mechanical vibration theory,gas mechanics and liquid mechanics,the mathematical model of the single-compartment oil-gas spring is deduced,and the nonlinear mathematical model of the 2-DOF vehicle-hydraulic suspension is established.Secondly,using the incremental harmonic balance method,the periodic response and time-domain response of a two-degree-of-freedom single-chamber oil-gas suspension dynamics model are obtained.Comparing with the fourth-order Runge-Kutta numerical integration method(RK method),it is verified that the IHB method can meet the calculation accuracy by taking three harmonic terms,and the IHB method(incremental harmonic balance method)was used to obtain the amplitude and frequency characteristics of the suspension system.The influence of the system parameters on the vibration characteristics of the system was studied.Thirdly,according to the similar system theory,the spring and damper in the mechanical system correspond to the resistance and capacitance of the circuit,respectively.The first-order equations obtained by the equations of the two-degree-of-freedom single-chamber oil-gas suspension system are derived and the corresponding circuit diagrams are according to the circuit diagram to get the circuit equation.The circuit is simulated by Multisim software and the phase diagram obtained by the circuit is compared with the numerical simulation results of the mechanical system.Verifying the feasibility of the mechanical system through the circuit simulation experiment provides a theoretical reference for the simulation of the mechanical model with the circuit system when it is difficult to establish a mechanical experiment system. |
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