Research And Design Of The Dual Coil Built-in Magnetorheological Damper

The shimmy is a self-oscillating shock during the aircraft's taxiing,the most effective way to prevent the shimmy is to install a damper.At present,hydraulic-type dampers are commonly installed on aircraft.Magneto-rheological fluid dampers have been studied and applied in fields such as machinery,automobiles,and building earthquake-resistance because of their fast response speed and adjustable damping force.Based on the fast response speed of the magnetorheological damper,the adjustable and damping characteristics of the damping force,which can effectively satisfy the different needs of the damping force of the landing gear shimmy damper caused by changes of the use environment such as different loads and different taxi speeds,and have the feasibility of replacing the existing hydraulic-type dampers.Based on the piston type damper,the magneto-rheological fluid is used as the medium,and a dual coil built-in magneto-rheological damper is designed based on the technical requirements of shimmy damper of a certain type UAV.The shimmy damper has two characteristics in structural aspects: the coil is directly fixed on the cap,which facilitates heat dissipation,and the damping channel is fixed,the piston structure is relatively simple and convenient for miniaturization.In the magnetic circuit,a double coil is used to provide a magnetic field,which is convenient for control.In the experiment,the two coils can add the same current and different current.Taguchi optimization algorithm is used to optimize the design parameters of the shimmy damper.The main factors affecting the damping force of the damper are the length of the damping channel,the damping gap,the effective area of the piston,and the size of the current.Based on the Taguchi optimization algorithm,the Max Well software was used to simulate the magnetic field.The difference between the simulated damping force and the required damping force of the damper and the adjustable multiple of the damping force were used as the objective function to optimize the structural parameters of the shimmy damper.Based on the optimization results,combined with the installation size of the shimmy damper of a certain type UVA,and the required equivalent damping coefficient,a shimmy damper has been designed and tested.Based on the calculation formula of the damping force of the shimmy damper,the theoretical output damping force of the designed damper is calculated and compared with the experimental data to verify the theoretical calculation method of the damping force,the relevant theory and the feasibility of the magnetic field simulation.The calculation formula of damping force of the damper is modified by experimental data.Analyzing the experimental data,the damper has good damping characteristics at low frequencies,the power map is full,the adjustable multiple is high,the response speed is slightly slower at high frequencies,and the adjustable multiple is reduced compared to the low frequency.Through the shimmy experiment,it was verified that the damper has a certain effect on the suppression of landing gear shimmy,which verifies the feasibility of the design scheme.