Magnetorheological Damper Design and Numerical Analysis for Assistive Knee Exoskeleton

This paper presents the design of MRD for assistive knee exoskeleton. The study aimed to design MRD to provide controlled and adjustable resistance to movement, primarily in the knee joint during flexion and extension to overcome excessive vibrations and shocks. Mathematical model of magnetic circuit according to Ohm's law was developed and ANSYS (Mechanical APDL 2022 R2) was used to build an axisymmetric FEM model to analyze the magnetic flux density, magnetic field strength, and other properties of the magnetic circuit. The dynamic performance characteristics of the damper was predicted based on Bingham's plastic model. The results demonstrated that the damper can provide a damping force of 446.6N at 1.1A current that will help to absorb and dissipate energy generated during movement, reducing impact forces and providing a smoother and more controlled motion. It will also minimize excessive vibrations and shocks, thereby improving user comfort and reducing the risk of injury.