Abstract
In the previous paper [1], a novel type of semi-active damper that is composed of a cylinder injected with Magnetic Fluid (M.F.) and a magnetic flux controller was proposed for improving the ride comfort of trains. In this paper, at first, a modified model considering nonlinear characteristic of M.F. such as a Non-Newtonian-Fluid is proposed. Next, in order to enhance the control effects, two kinds of improvements are made in the semi-active damper. One is to change the voltage control input to an electromagnet into the current control input. The other is to expand the control range for the M.F. damper by means of feeding a bias current to the electromagnet. Finally, the effects of the improved semi-active damper are shown by various digital simulations and vibration experiments.