Design of a New Magnetorheological Damper Based on Passive Oleo-Pneumatic Landing Gear

Abstract

In this research, a new type of magnetorheological (MR) damper, applicable to the landing gear system of airplanes, is presented. As a first step, an oleo-pneumatic damper, which is used for the landing gear system of small airplanes, is adopted. Its damping force is tested to determine the principal design parameters for the proposed MR damper. Thereafter, the structural configuration of the MR damper is characterized according to the operating principles of the adopted damper. The MR damper has two orifices and a recoil valve where one orifice is to be controlled by the flow direction. An analytical model for the field-dependent damping force is derived under both compressed and extended modes, followed by the analysis of the magnetic field intensity of the MR damper using the finite element method. After investigating the field-dependent damping characteristics, the dynamic equation for half of the airplane model is derived, and a simple, but effective, skyhook controller is formulated by considering the safety condition. Through computer simulations, it is shown that the proposed MR damper can provide the best vibration control and highest efficiency, which indicates the shock absorption capability of the damper during the landing stage.