Design Of The Pumping Magneto-rheological Damper And Its Application Simulation On Vehicle

Damper as an important part of suspension system is to isolate the vehicle body andpassengers from road surface disturbances. Compared with conventional passive damper,semi-active damper can improve the ride comfort and handling safety. MR（Magnetorheological） damper has many virtues such as broad controllable force range,fast response time, simple structure and low power, so that it has attracted considerableinterest recently.MR damper has a commercial products abroad, but due to the technological monopoly,its price is very high. Meanwhile single-tube MR damper has following shortcomings:(1)working cylinder has poor ability to withstand external bump;(2) gas chamber needs highsealing performance, so good manufacturing quality is required. Double-tube MR damperhas poor cool ability. In this paper, PMRD (Pumping MR damper) is personally designed,which has good cool ability, high reliability, simple configuration. The technologies of MRdamper are studied by adopting the methods of theoretical simulation and experimental study,meanwhile the control method of semi-active suspension system based on PMRD is studied.According to the above object, major work of the article is as follow:1) Design and magnetic analysis of the PMRD. First, according to original car data,external characteristic curve of the PMRD is gained, the structural parameters arecalculated, the materials of related components are selected; then using magneticfield finite element analysis software, the character of magnetic field is analyzed,including the comparison between double coil and single coil, comparison betweencurrent direction of double coil. The rule of key parameters affecting the magneticproperties is obtained: magnetic intensity increases with the increase of inside plate thickness, outside plate thickness and the applied current, and with the decrease ofthe gap size; finally, semi-empirical model of the magnetic intensity is established.2) Optimal design of PMRD. Firstly, mathematical formula of the response time isaddressed; then, on the basis of basic knowledge of fluid mechanics and Binghamplastic model, the theoretical model of damping force is derived; finally, usingco-simulation of the Matlab and Isight, multi-objective genetic algorithm asoptimized method is adopted, the optimization is carried out by damper force andrange of controllability as objective function, the structural parameters of themagnetic supply system as design variables, the response time and maximum shearyield stress of magnetorheological fluid as constraint conditions, by optimizing, anappropriate set of structure parameters is obtained.3) Experiment and dynamic character of PMRD. The sample is designed andmanufactured according to the result of optimization, and then tested with MTSsystem, experimental results show that (1) damping force of PMRD and hysteresisof damping force increases with the increase of speed and current;(2) characteristiccurve shows that feature of PMRD is non-linear;(3) when current direction ofdouble coil is reverse, the character of PMRD including damper force and range ofcontrollability is better than the same direction. Finally, based on the experimentaldata, the accuracy of the simulation result is verified, a mathematical model isadopted to characterize the dynamic response of the MR damper.4) Semi-active suspension ride simulation based on PMRD. The sky hook logic isadopt to calculates the ideal damping force, and the fuzzy control logic is used toadjust the electric current to make the practical force track the ideal force. Bysimulation, the performance of semi-active suspension with PMRD is better thanthe original passive suspension.