Design of a Low-Cost Prosthetic Leg Using Magnetorheological Fluid

Abstract

This chapter deals with the design and modeling of a prosthetic leg for above-knee amputees using magnetorheological (MR) fluid. MR fluid is a smart material, which changes its rheological properties according to the magnetic field around it. It is essentially constituted of a carrier fluid (some organic/inorganic oil), ferromagnetic particles and additives for better stabilization. This smart material has found its application in the field of biomechanics, prosthetics to be more precise. Using it as a working fluid in a device like a damper, one can quickly achieve the required forces and torques to achieve limb-like movement. This chapter illustrates a prosthetic leg’s design whose knee joint can be controlled by an MR damper. A few MR dampers and details of the design and construction of a twin-tube MR damper are also discussed. A complete kinematic analysis using the software ‘SOLIDWORKS’ is shown and discussed in detail. Dynamic analysis of a human leg using the analytical method is illustrated. Both computational fluid dynamics (CFD) using ANSYS Fluent and magnetic analysis using COMSOL have been explained. Various control strategies to stabilize the system are also discussed. This is the field of research that has an ever-increasing demand because the number of amputees globally is increasing at a very high rate.