New Electro-Hydraulic Foot Prosthesis

This project develops an electronic-controlled version of the advanced hydraulic foot/ankle (MCI Foot) demonstrating the feasibility of the automatic adjustment of resistance throughout the range of motion. The advanced MCI Foot, especially the automatic-controlled version, contributes to the function of the prosthesis wearer, resulting in advanced and more natural walking benefits. The project objectives include: (1) Implementation of electric servo-valves into the existing foot-ankle design. Manual valves have been developed at present, and in preliminary testing, shown to be successful at setting the foot wearer’s preference for dorsi-flexion and plantar flexion; (2) Development of sensor for ankle position, inclination, temperature, and load for integration into the ankle electronic Controller. The sensors utilize a rugged design, for long-term reliable usage in the foot, and small size to fit within the anatomical shape of the foot; (3) Implementation of an algorithm for ankle control by microprocessor. The automatic control of ankle resistance depends upon the variable of position, inclination, and load, indicating the point in the gait cycle in which the walker’s step is taken. The temperature is automatically compensated for as the hydraulic fluid warms and changes viscosity. Success in the function of the auto-controller is evaluated in-house, in the Foot Testing Center.