Thermal Effects of a Homogeneous ER Fluid Device

The viscous coefficient of a homogeneous ER fluid can be changed by the application of an electric field. However, the ER effect of the fluid is easily varied by temperature variation. Therefore, an envelopment and time in which the fluid is applied is limited. In this paper, we examine the influence of the thermal effects induced on the fluid by the device, in order to construct more reliable homogeneous ER devices. We discuss two kinds of thermal effects caused by joule heat and the dissipation of viscous energy. The results of simulations and experiments suggest that most of the exothermic elements of the homogeneous ER fluid are caused by the dissipation of viscosity energy in the fluid. Therefore, it seems reasonable to drive the clutch at a low rotating speed for short periods. We think that a robot arm for impedance control is more effective than a damper for vibration control.