Design and Simulation of a Rotating Magnetorheological Fluid Damper for the Ankle Rehabilitation Robot

The existing rehabilitation robots are not compliant enough, which can easily lead to the secondary injury of patients. Magnetorheological fluid (MRF) can be used to change the damping force of the mechanism and then is applied to the compliant mechanism because it changes its yield stress with the change of magnetic field. In this study, a rotating magnetorheological fluid damper was designed and its mechanical model was established to calculate its output torque. A magnetic field simulation of the designed rotating magnetorheological fluid damper was analyzed. The relation between the magnetic field of the MRF in the damper and the input current was investigated, which can obtain the output torque of the rotating magnetorheological fluid damper by controlling the input current. Finally, a prototype of rotating magnetorheological fluid damper and a 1-DOF ankle rehabilitation robot based on the rotating magnetorheological fluid damper were built to test the performance of designed damper and conduct rehabilitation training.