Performance Analysis And Optimization Of Combat Vehicle’s Hydro-Pneumatic Suspension

Taking the hydro-pneumatic suspension of a certain type of combat vehicle as the research object and aiming at improving the ride comfort and handling stability of the combat vehicle under complex road conditions,a complete mathematical model of the combat vehicle hydro-pneumatic suspension is established by using fluid mechanics and fractional differential theory.On this basis,its stiffness characteristics,throttle damping characteristics and friction damping characteristics are analyzed,Thus,the optimization and improvement direction of the device is proved: an adaptive damping adjusting device based on pressure feedback principle is invented to improve the adaptability of hydro-pneumatic suspension to road conditions;the technology of variable clearance seal and surface texture is proposed to improve the suspension cylinder to reduce friction and wear;the nonlinear coupling dynamic model of road suspension load multi system is established to optimize the working parameters of hydro-pneumatic suspension.The specific work is as follows:Aiming at the problem that the damping device in the hydro-pneumatic suspension of a combat vehicle can not change the throttle damping according to the road conditions,an adaptive damping adjustment scheme based on the pressure feedback principle is proposed,and the corresponding adaptive damping adjustment device is designed.By establishing the mathematical model of the damping adjusting device under different working conditions,combined with the classic suspension design theory of the vehicle,the initial design parameters of each part are obtained,and the influence law of each parameter change on the damping characteristics of hydro-pneumatic suspension is obtained,which lays a foundation for the study of multi-objective parameter optimization.The test shows that the device can feed back the road condition information to the comparison piston depending on the change of hydraulic parameters,so as to control the adaptive adjustment of throttle port size and realize the better matching of road condition and damping.The road condition detection,signal feedback,deviation comparison and adjustment are all completed by the built-in self-adaptive damping adjustment device,which saves space and has good reliability.The theoretical adaptability of the combat vehicle to road conditions is improved from level B to level D.In order to solve the problems of high friction resistance and low dynamic response of the hydraulic cylinder of the hydro-pneumatic suspension of a combat vehicle,a combined structure of textured inner wall of the cylinder and variable clearance piston seal was proposed.Firstly,the mathematical model of piston lip deformation is established and its deformation law is simulated.Secondly,the bionic reticulate texture model was constructed by simplifying the biological surface morphology structure,and its tribological properties were numerically solved.The distribution of oil film pressure and velocity on the textured surface was studied by CFD flow field simulation,and the formation mechanism of hydrodynamic lubrication was explored.Then,the effect of texture lubrication on drag reduction was tested under different rotating speeds,clearances and temperatures,and it was found that the friction reduction lubrication performance was the most stable when the texture angle was 45°.Finally,the friction coefficient of variable clearance seal hydraulic cylinder with reticulate texture is reduced by more than 50%compared with that of ordinary hydraulic cylinder.Aiming at the problem of optimization and matching of the design parameters of the hydro-pneumatic suspension of a combat vehicle,a nonlinear coupling dynamic model of the road suspension load multi-system is proposed.Taking the ride comfort and handling stability of the vehicle as the evaluation index,the multi-objective optimization of the design parameters of the hydro-pneumatic suspension system is studied by using genetic algorithm.The optimization results show that the maximum reduction of the root mean square value of the body acceleration is 46.5%,the maximum reduction of the root mean square value of the wheel dynamic load is 24.3%,and the maximum reduction of the root mean square value of the suspension dynamic deflection is 44.9%.The performance of the optimized hydro-pneumatic suspension is significantly better than that of the existing hydro-pneumatic suspension of a combat vehicle.Through the design of vehicle hydro-pneumatic suspension test platform,each model is tested and verified,and the test results are in good agreement with the simulation results.The test results show that,for the optimized hydro-pneumatic suspension system,the root mean square value of vertical acceleration and the root mean square value of suspension dynamic deflection decrease by more than 30%,the root mean square value of wheel dynamic load decrease by more than 20%,and the maximum decrease of acceleration peak value is 38%.The test results show that the optimized hydro-pneumatic suspension can effectively improve the ride comfort and handling stability of a combat vehicle.