Young-Won Yun, Seong-Min Lee, Myeoung-Kwan Park*
The Journal of Mechanical Science and Technology, vol. 24, no. 11, pp.2297-2305, 2010

Abstract : This study describes the development, modeling, and testing of a hybrid damper for semi-active suspension. The goal of this study is to improve the performance of conventional passive oil dampers using a magneto-rheological (MR) accumulator that consists of a gas accumulator and an MR device. The level of damping is continuously variable by means of control of the applied current in an MR device that is fitted to a floating piston that separates the gas and oil chamber. A small MR device is used to resist the movement of the floating piston. At first, a mathematical model that describes all flows within the damper is formulated and developed in Matlab/Simulink. The MR device is also devised. A mathematical model is adopted to characterize the performance of the device. The formulas derived for the different components of the damper force are combined into a full damper model. Then, the applicability of the MR device to a conventional passive oil damper is tested in a manufactured test environment and evaluated in terms of the damping force vs. the piston velocity. From the results, it is possible to ascertain the MF device’s capability to work as a damper that can supply a variable damping force. Moreover, this research affords a lot of new information about the applicability of MR devices and improvement of the damping force.

Keyword : Magneto-rheological fluids; Oil damper; Floating piston; Accumulator