Research On A Vehicle Active Suspension Device And The Control Strategy

Acting as an important component of the vehicle system, the suspension system hasa critical influence on the vehicle running smoothness, riding comfort and handlingstability. Compared with the passive suspension, the active suspension can generateand regulate the control force proactively based on the road timely input so that thevehicle can have great vibration isolation performance and maximize the performanceof the suspension system. Therefore, research on the vehicle active suspensiontechnology has a broad application prospect and a very important practicalsignificance.This dissertation mainly combined with the program named “Research on inertialcontrol suspension technology”, which is one of key planning projects of thetechnology development program in Jilin province. In this paper, the developmentsituation and trend of active suspension technology at home and abroad are analyzed.In order to improve the vehicle riding comfort and handling stability, anelectro-hydraulic servo active suspension system based on a hydraulic cylinderactuator controlled by a servo valve is designed and research on fuzzy control strategyand variable universe fuzzy control strategy of active suspension system is conductedin this paper.This paper firstly analyzes the impact of the vehicle suspension system on thevehicle riding comfort and handling stability. Based on this, an evaluation ofsuspension system is put forward. A seven-degrees-of-freedom vehicle suspensionmathematical model is established and modeling of random road input is put forward.Through the study of the vehicle active suspension system, an electro-hydraulic servoactive suspension system based on a hydraulic cylinder actuator controlled by a servovalve is designed. At the same time, the study on active suspension control strategies is conducted and fuzzy control strategy, which is much more robustness and does notneed a precise mathematical model of the controlled object, is used as the vehicleactive suspension control theory. The variable universe fuzzy control strategy is putforward in order to further improve the accuracy of the control. Then, a fuzzycontroller and a variable universe fuzzy controller are designed for the activesuspension system. In order to verify the control effect of the two active suspensioncontrollers, a road random input model, a passive suspension model and an activesuspension model are created under the Matlab/Simulink software environment andsimulation experiment is conducted by using the models. The simulation results showthat, compared with the passive suspension, the active suspension using the fuzzycontrol strategy and the variable universe fuzzy control strategy in this paper caneffectively reduce the vertical vibration, pitching and rolling of the vehicle body underrandom road input and reduce the fluctuations of tire dynamic load of the vehicle, sothat the vehicle has a better riding comfort and handling stability.