Damping properties for vibration suppression in electrohydraulic servo-valve torque motor using magnetic fluid

Aiming to suppress high frequency vibrations of a torque motor in electrohydraulic servo-valves, damping properties of an ester-based Fe ₃O₄ magnetic fluid operating in the squeeze mode are studied in this Letter. The expression of damping forces due to the magnetic fluid on the torque motor is derived and simplified based on the measured magneto-viscosity property. Dynamic characteristics of the torque motor with and without the magnetic fluid are simulated and tested. Damping properties of magnetic fluid for the vibration suppression of a torque motor are verified by the good agreement between the predicted and tested results.