Research On Active And Passive Switchable Suspension System For The Special Vehicles

The suspension system of the vehicle directly affects its ride comfort,safety and operational stability.Because the traditional passive suspension system has a fixed stiffness and damping,in the case of complex and variable road conditions,its performance is difficult to meet the normal needs of people,not to mention the special emergency rescue vehicles.Therefore,it is particularly urgent to develop a time-varying stiffness and damper suspension system,or to use active suspension system to adjust body attitude at all times in order to improve ride comfort.This paper relies on the national key research and development plan "The key technology research of High-mobility emergency rescue vehicles’(including fire-fighting vehicles)special chassis and suspension"(project number:2016YFC0802902),and based on my large number of reading domestic and foreign related literature,mainly for Hydro-pneumatic Suspension System and active suspension system are studied in depth.The specific research work is as follows:1.The switchable principle of active and passive suspension system is introduced,and the mathematical model of single-bridge interconnected Hydro-pneumatic suspension under passive condition is established.The effects of different structural parameters and external excitation parameters of Hydro-pneumatic suspension on its displacement,velocity,stiffness and damping characteristics are analyzed.2.Based on the physical model of the vehicle,the dynamic models of the9-DOF Hydro-pneumatic suspension system and the active suspension system are established respectively.Correlation analysis was carried out on the input excitation of the left and right wheels of the vehicle,a random pavement model was established,and the performance evaluation index of the suspension system was pointed out.3.A generalized error dynamics model based on the ideal skyhook dampingreference model is established,and the sliding mode controller is designed.The fuzzy control strategy is used to optimize the gain of the approaching law coefficient of the sliding mode control,and the universe of the fuzzy controller is transformed by artificial intelligence.A variable-universe fuzzy sliding mode variable structure controller is designed.4.The simulation model of the Hydro-pneumatic suspension and active suspension is built with Simulink.The simulation results show that the performance of the active suspension is better than that of the Hydro-pneumatic suspension,which can improve ride comfort.