Research On A Control Method For Front Energy Absorption Structures Of Passenger Cars With Magnetorheological Damper

With the continuous improvement of road conditions,passenger cars driving speed have been rapidly increase,the safety performance demand of vehicles has become more and more strict.The front energy absorption structures of passenger cars have an important role in improving the passive safety performance of the vehicle.The traditional energy absorption structures in the collision conditions neither adapt the buffer effect,nor achieve better protection effect.Magnetorheological damper,based on magnetorheological technology,has the characteristics of large output resistance,damping continuously adjustable,wide dynamic range and fast response speed,which orientates the new direction for developing intelligent energy absorption structures.Therefore,it is important to study the influence of the control method of the magnetorheological damper on the impact of the collision buffer,and it is of great significance to broaden the application range of the magnetorheological damper and the passive safety performance of the passenger cars.The main research contents include the following aspects:(1)In this paper,the research status of magnetorheological damper and the significance of the application in the collision condition of passenger cars are described.Based on the Bingham-plastic modify(BPM)model,the mathematic model of the magnetorheological damper at high speed is deduced,and the dynamic characteristics of the magnetorheological damper are analyzed.The nonlinear dynamic model of the magnetorheological damper is proposed,which laid the foundation for the next work.(2)The nonlinear dynamic model of the magnetorheological damper is identified by using the damped least squares method,and the results of the parameter recognition are verified though simulation.The inverse dynamic model of the magnetorheological damper is established based on the BP neural network,and control current of the magnetorheological damper is calculated.This work provides the condition for the study of the control method of the magnetorheological damper.(3)The vehicle two-degree-of-freedom collision model is developed by using the spring/damping-mass method.Based on the vehicle’s state parameters,the LQR controller is designed to obtain the optimal control force.According to the expected control force,the BP reverse model and the fuzzy control are used to calculate the control current,and comparative analysis is made about the control effect,the better one is chosen as control method.(4)The finite element model is simplified and two kinds of finite element collision models which include without damping element and with damping unit are established.The energy dissipation,speed and acceleration of the energy tank and the front beam are compared and analyzed to determine the buffer energy absorption effect of the magnetorheological damper.