Design And Key Influence Factors Analysis Of Rotary MR Damper

With the development of the magnetorheological(MR) technological application, rotary magnetorheological dampers have been used in more and more control occasions. Such as the force feedback device of steer by wire, driving control of unmanned aerial vehicle,ABS controller rotor system vibration control and so on.In these occasions, not only output torque and volume. are considered,but also the response speed, energy consumption and controllability are becoming more and more important. the requirementsfor the key performance differ in different situations. Based on these different requirements, a series ofevaluation indexes of rotary MR damper is proposed in this paper.In addition, the key factors which influence the performance are analyzed.The specific works include the followings.(1) The distinction and relation of several MR fluidmodel were analyzed.Based on the practical application,the simplified model between the magnetic shear yield stress and magnetic flux density was constructed.(2) Based traditional disc and drum MR damper,a new MR damper with T-shape rotor was proposed,which works on all end and side faces.According to the torque models of disc and drum MR damper,the torque model of T-shape rotor damper was derived.(3) The evaluation criterion indexes were built, which include the torque desnsity, the efficiency, the controlbility, the torque response. The parametric formulas of the key structures were derived.The different evaluation criterion indexes were expressed as expected magnetic flux density, rotor radius,rotor length and fluid gap of these three MR dampers. Then, the relationship between the structure parameters and evaluation criterions was studied, the result shows that the rotor radius, the rotor length, the fulid gap and the coil average radius are the key influence factors of the rotary MR damper.(4) The simulations were built to investigate the validity of theoretical research. Some suitable parameters of structure and material were chosed to build the three MR damper ifinite element anynasis(FEA) models in ANSYS software.The errors of magnetic flux density between simulation value and theoretical value were compared.Besides,The keyperformance influence factors of the three dampers werestudied and comparedwithin the Matlab software,the proposed evaluating indicators were researched by changing the rotor radius, MR fluid gap,coil average radius and rotor thickness.Finally,The results reveal that all the criterion indexes except the controlbility increase quickly with the rotor radius growing,on the contrary, the controlbility shows the the opposite trend, beyond that, the torque density, the torque response. the controlbility of the T-shape rotor MR damper are better than the traditional drum damper and the disc damper. The fluid gap affects the power consumption and the response time of the rotary MR dampers, the power consumption increases with the fluid gap growing but the response time decreases. The growing of the coil average radius will raise the power consumption and shorten the response time, and there is a optimum coil average radius minimize the volume of the MR damper. The power consumption and the response time do not change with the rotor length, the power consumption of the dis MR damper increases with the rotor length,but the response time showed a opposite trend. As for the disc and the drum dampers, a optimum rotor length exists which maximize the torque density.