In this study, a semi-active magnetorheological (MR) damper for the main landing gear suspension system of the aircraft is proposed. MR damper is designed with two magnetic cores to control the effective damping force and also with annular bypass for fast expanding speed considering the characteristics of the aircraft landing. A controllable yield force of the MR fluid with respect to the input current is analyzed as a first step, and a vertical landing model with MR damper is considered to evaluate aircraft landing efficiency. In this work, a sky-ground controller is designed and applied to MR damper to maximize the landing efficiency of the drop simulation. The damping force of MR damper is controlled by the input current calculated by the proper choice of the sky hook gain and ground hook gain, respectively. It is demonstrated through the comparative work between the passive and proposed semi-active MR damper based landing gear that the landing gear efficiency of the passive damper can be enhanced a lot showing the efficiency above 90%.
Airplane landing gears are subjected to a wide range of excitation conditions due to variations in sink speed and road condition. An existing passive type damper for the landing gear is hard to satisfy these various conditions. A semi-active type magnetorheological (MR) damper is one of attractive solutions to resolve this problem. This work presents design and analysis of MR damper applicable to the landing gear system. MR damper is designed based on the required damping force and packaging constraints. Especially, the geometry of the magnetic core is optimized in terms of magnetic intensity at magnetic poles to achieve uniform magnetic intensity under the packaging constraints. The effectiveness of the proposed MR damper is given by presenting the field-dependent damping force and the efficiency.
This paper proposes a new type of a direct-drive valve (DDV) suspension system for vehicle controlled by the piezostack actuator associated with displacement amplifier. In order to achieve this goal, a new type of controllable piezostack DDV damper is designed and its performance evaluation of damping force is undertaken. Next, a full vehicle suspension system consisting of sprung mass, spring, tire and the piezostack DDV damper is constructed. After deriving the governing equations of the motion for the proposed the piezostack DDV suspension system, the skyhook controller is implemented for the realization of the full vehicle. Analytical model of the whole suspension system is then derived and performance characteristics are analyzed through numerical simulation. Finally, vibration control responses of the vehicle suspension system such as vertical acceleration are evaluated under both bump and sine road conditions.