Thermal equilibrium in a dynamic electrorheological fluid model of a high-speed traversing/positioning mechanism

A high speed traversing/positioning mechanism using two electro-rheological clutches is described. The traversing mechanism can be used to wind filaments onto bobbins. The traverse speed is 5 m/s, the required turn round period is 10 to 20 milli-seconds, the traverse length is 250 mm, the turn around position must be controllable and repeatable within +/- 1 mm and the traverse requires to be controlled to shape the resulting bobbin ends. These combined criteria of high speed and controllability makes the use of electro- rheological fluids a potentially viable solution. A dynamic simulation is available to predict the performance of the mechanism, however, a number of the electro-rheological fluid properties required by this simulation are temperature dependent. The methodology for predicting the thermal equilibrium temperature of the electro-rheological fluid within the high speed traversing mechanism is presented. Heat generation within the electro-rheological fluid, due to the fundamental operating mechanics of the mechanism, shearing of the electro-rheological fluid and the electrical excitation, are combined with the heat transfer from the mechanism to enable the operating temperature of the fluid to be determined. This operating temperature enables the temperature dependent fluid properties to be used in simulating the dynamic performance of the mechanism.