ER Fluid Applications to Vibration Control Devices and an Adaptive Neural-Net Controller

Abstract

This article describes several applications of electro-rheological (ER) fluid to vibra tion control actuators and an adaptive neural-net control system suitable for the controller of ER ac tuators. ER fluid is a kind of colloidal suspension, and has a notable characteristic feature in that its apparent viscosity can be controlled in response to applied electric field strength. Viscosity can be varied in a wide range and the response time is very short, as short as several milliseconds. Accord ing to previous studies, one promising application is a controllable damper. In the present article, four applications are proposed: a shock absorber system for automobiles, a squeeze film damper bearing for rotational machines, a dynamic damper for multi-degree-of-freedom structures and a vibration isolator. Furthermore, an adaptive neural-net control system, composed of a forward model network for structural identification and a controller network, was introduced for the control system of these ER actuators. As an example study of intelligent vibration control systems, an experi ment was conducted in which the ER dynamic damper was attached to a beam structure and con trolled by the present neural-net controller so that the vibration in several modes of the beam was reduced with a single dynamic damper.