Design Optimization of Miniature Magnetorheological Valves with Self-Sensing Capabilities Used for a Wearable Medical Application

Magnetorheological (MR) fluids are materials characterized as intelligent since their rheological properties may be controlled by the excitation of an external magnetic field. The application of the latter brings the fluid from a liquid to a semi-solid state. Due to their properties, these materials are widely used, among others, in biomedical applications. In the present work, multiple MR valves are incorporated as pressure limiters in a smart biomedical insole for diabetic patients. The diabetics are affected by high plantar pressures that cause ulceration and frequently, as a consequence of ulceration, lower extremity amputation. This novel insole aims at the active plantar pressure offloading. Thus, considering the small size of the insole, the number of the valves, as well as the high plantar pressures that reach up to 1 MPa on diabetic feet, a study is performed on optimizing the design of the MR valve, exploiting the Design of Experiments (DoE) techniques. Moreover, a testbench is presented for the examination of pressure self-sensing capabilities of the valves, with a future goal to integrate them in the design optimization and acquire a sensorless system.