| With the development of science and technology as well as the modern automobile industry,the hydro-pneumatic suspension system is widely used in the fields of military tanks,excavator,crane and high-grade car due to its good vibration damping performance.The performance of suspension has a direct impact on the vehicle's mobility,safety and comfort,so research how to improve the performance of hydro-pneumatic suspension is necessary.It integrates with elasticity and damping at an organic whole without single shock absorber;because there is huge energy storage in every unit,the size of the hydro-pneumatic suspension is relatively small and it can be conveniently decorateed in the vehicle.In addition,compared with the traditional suspension system,non-linear damping and nonlinear stiffness of the hydro-pneumatic suspension are important characteristics,which make the safety and comfort of vehicle have greatly improved in the process of driving.In this study,the double chamber hydro-pneumatic suspension was taken as research object.With Matlab/Simulink system simulation and analysis,the characteristics of its non-linear stiffness and nonlinear damping were deeply investigated;the model of passive hydro-pneumatic suspension was established;on the basis of different control methods,three kinds of active hydro-pneumatic suspensions were established.And investigation in the performance of the suspension was carried out and good results were obtained.Details are as follows:1.The hydro-pneumatic suspension was modeled and simulated analysis.According to the working principle of hydro-pneumatic suspension system,a non-linear mathematical model of hydro-pneumatic suspension system was established and the nonlinear mathematical expression of the piston rod stress was deduced.To study the stress of the piston rod in hydro-pneumatic suspension system,when the road input filter were white noise A,B and the sinusoidal signal respectively.2.Parameters of the hydro-pneumatic suspension system were optimized and dynamic simulation.Research the stiffness and damping characteristics of the hydro-pneumatic suspension;through optimizing the structure parameters of the suspension system,the two kinds of features were linearization;To set up two degrees of freedom dynamic model of 1/4 vehicle,under the different road input,the linear and nonlinear of hydro-pneumatic suspension system were simulated.3.The active controller of hydro-pneumatic suspension system was designed.The theory knowledge of PID control,fuzzy control were detailed introduced,and based on three kinds of active control strategy,the active control hydro-pneumatic suspension was designed.4.Simulation study of the active Hydro-pneumatic suspension.Compared the three kinds of active control hydro-pneumatic suspension with the passive one,with the road inputs of white noise A,B and sine signal.The simulation result was that the performances of the active control suspension were improved on suspension dynamic deflection,wheel dynamic load and the center of mass acceleration. |
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