Abstract:The design method of a new type multidisc MRF damper with large output damper torque, low initial damper force is introduced. The magnetic elements, nonmagnetic elements and magneto rheological fluid (MRF) in the gap constitute a closed serpentine flux path inside the damper. Aiming at the leakage problem, the design idea of ferrofluidic sealing is adopted, which significantly reduces the friction force at the rotating shaft. Based on the Bingham plastic model, the paper analyzes the mechanical characteristics of MRF, and derives the damper torque model. The ANSYS Maxwell software is used to conduct the finite element analysis of the damper, which verifies the accuracy of the flux path, and then the structure of the damper is improved on the basis of the original design. Finally, a small volume MRF damper was developed. An experiment platform was built by our own, on which torque measurement experiment and response time measurement experiment were carried out; the experiment results verify that the damper has the characteristics of large output torque, low initial damping force and low response time. The diameter of the damper is 33.6 mm, its height is 21.6 mm, and the weight is about 200 g; when the input current is 1.2 A, the output torque is about 350 N·mm, which reaches the required torque for the operator to grasp virtual objects.