Design and Experimental Validation of an MR-Fluid Based Brake for Use in Haptics

In this work, the design of an MR-fluid based brake system is given which is aimed to be used in kinaesthetic haptic devices. The brake design proposes a solution to the stiction problem which is common among the MR-brake based haptic devices. This problem occurs when the brake is activated to constrain the motion of the handle in one direction and the user wants to move the handle in the other direction. The development process, which consists of 3D designing, Finite Element Analysis (FEA) simulation and mathematical modelling, aims to achieve the optimal design with high performance to volume ratio. The prototype design is constructed, and its performance is evaluated via experimental tests. A polynomial equation is calculated to fit the experimental current-torque data, which captures the hysteresis behaviour of the system. According to the test results, the applicable torque range of the prototype is from a minimum of 0.15 Nm to a maximum of 3.8 Nm and the bandwidth is calculated to be 63 rad/s.