Powered Transtibial Prosthetic Device Control System Design, Implementation, and Bench Testing

Abstract

This article outlines the controller design for a specific active transtibial prosthesis. The controller governs the power output of a DC motor attached to a fourbar mechanism and torsional spring. Active power reinforcement is used to assist the push off at later stages of the stance phase and achieve ground clearance during the swing phase. A two level control algorithm which includes a higher level finite state controller and lower level proportionalintegralderivative (PID) controllers is applied. To implement this control algorithm, a digital signal processor (DSP) control board was used to realize the higher level control and an offtheshelf motor controller was used to realize the lower level PID control. Sensors were selected to provide the desired feedback. A dynamic simulation was performed to obtain the proper PID parameters which were then utilized in a bench test to verify the approach.