Viscous control of a rotating device using smart fluid

Homogeneous electro-rheological fluid (ERF) is a smart fluid that can control its viscous coefficient by applying an electric field. Therefore, an application of this fluid can create a damping device in a mechanical system. However, an ER effect of the fluid is easily changed by shear rate variation or temperature variation. In this study, a viscous coefficient control method using variable structure control is proposed, and the application of the control method to a clutch using homogeneous ERF is demonstrated. As a result, the viscous coefficient of the clutch was accurately and speedily controlled by the proposed control method. Therefore, it is possible to obtain a reliable ER device that is not influenced by variations in this fluid property.