Development of an MR-brake-based haptic device

This paper describes the design, testing and modelling of a magneto-rheological (MR) fluid brake as well as its application in a haptic device. The MR device, in disc shape, is composed of a rotary shaft and plate, an electromagnetic coil, MR fluids, and casings. The working principle of the actuator is discussed and the transmitted torque equation employed by using the Bingham plastic model. The optimal dimensions of the actuator were obtained by finite-element analysis using the COSMOSEMS package. Following manufacturing and fabrication of the actuator prototype, the steady-state performance of the MR actuator was measured using a force gauge. The experimental results show that the actuator exhibits hysteresis behaviour. A sub-hysteresis model was then proposed and the model parameters were identified. Example applications of this actuator in virtual reality are demonstrated.