Study On Modeling And Control Algorithm Of MR Damper

Shimmy damper is located in the aircraft's nose landing gear, which is used to reduce shimmy. Shimmy is the lateral swing of nose wheels when aircraft is takeoff or landing, caused by the force between the tires and the runway and the influence of the airframe vibration. Shimmy is harmful, the most direct and effective way to reduce shimmy is to install shimmy damper. Traditional shimmy damper mostly use oil as damp fluid, which is cheap and simple, but this type of shimmy damper has fixed damping, it can't quickly reduce shimmy when there is violent disturbances and waste of energy when the aircraft is cornering. Shimmy has obvious nonlinear characteristics because the motion of the nose landing gear system is complex with lot of nonlinear force, which makes the study of shimmy difficult.Using magnetorheological(MR) fluid in shimmy damper may improve the situation. The research based on MR technology and ADAMS software, the former is a kind of smart materials whose damping can be changed by variable external magnetic, the latter can create virtual prototype and simulate the complex nonlinear forces like the MR shimmy damper's damping force.Firstly the model of nose landing gear with MRF shimmy damper was established by CATIA software and its virtual prototype was established by ADAMS software, non-linear shimmy was researched by simulation analysis, and the relationship between shimmy, shimmy damping and aircraft's velocity was clarified,the prior experience of fuzzy controller of MR shimmy damper was founded. Then the mechanical model of MR shimmy damper was established, and its fuzzy controller was designed. Finally, using ADAMS software and MATLAB software to make co-simulation to research MR shimmy, by comparing the results of shimmy between MR shimmy damper and normal shimmy damper, proved that MR shimmy damper can better reduce shimmy.