Comparison of Static and Dynamic Models for the Force Output of Magnetorheological Dampers

Magnetorheolgical (MR) fluid dampers have the capability of changing their effective damping force depending on the current input to the damper. A number of factors in the construction of the damper, as well as the properties of the fluid and the electromagnet, create a dynamic response of the damper that cannot be fully described with a static model dependant on current and velocity. In this paper, a static deterministic model for the force response of a damper will be compared to a time dependant dynamic model. Data collection was performed by providing a normally distributed random signal for velocity and a uniformly distributed random signal for current to Lord rheonetic seat damper; the signal distributions were chosen so dynamic effects were not artificially reduced. The parameters for the static and dynamic models were found by minimizing the error in force output. The error of the models is then compared, as well as the probability distribution for both models and the original data.Copyright © 2007 by ASME