Design Outlook of a Magneto Rheological (MR) Damper for Prosthetic Knee Use
In this work, a magneto rheological (MR) damper is designed based on swing-phase trajectory of an above-knee prosthesis where damping effecting is principal. Initially, a swing phase model of the desired single axis knee incorporating MR damper is built. A parametric model is utilized to represent the dynamic properties of the damper. The damper parameters that govern damping force of the damper are identified and optimized to enable the prosthetic knee to produce near normal swing phase trajectory for level-ground walking as obtained from experimental data. Based on the optimal damper parameters, the design of an MR damper valve, which is geometrically constrained in a desired cylindrical volume, is developed and its performance is evaluated for the intended application. Ideal structure of the damper is also proposed. The results show the designed MR damper is better than off-the-shelf MR dampers for the application, up to 70.4% reduction in weight has been achieved.
Keywords - Prosthetic Knee, Swing Phase, Magneto-Rheological (MR) Damper, Damping Force.