Optimization of a Hybrid MR Rotary Damper with Waveform Boundary Using in a Prosthetic Knee

The study focuses on the optimal design of a hybrid rotary MR (Magneto Rheological) with waveform boundary T-shaped rotor as prosthesis knee. In the biomechanical prosthesis knee MR fluid to create a variable braking torque depending on the magnetic field is used. By applying a magnetic field, the viscosity of the fluid is actively controlled to achieve the desired braking torque. After a brief description of the configuration of the rotary damper; achievable braking torque formulas is presented. In the following, optimization problem aims to find the optimal geometry in order to maximize the on-state braking torque while off-state torque and weight are within the permitted range. Depending on the application of the referred damper, the maximum braking torque, minimizing torque at off-state, minimizing damper’s weight and have uniform flux density are under consideration. The results of the optimized rotary damper are compared with the reference brake. Then, the performance improvement of the optimized MR brake is discussed.