An Adjustable Single Degree of Freedom System to Guide Natural Walking Movement for Rehabilitation

Abstract

This paper presents a linkage system designed to guide a natural ankle trajectory with the corresponding foot orientation. A sixbar linkage was designed to coordinate the joint angles of an RR chain (R denotes a revolute or hinged joint) that models the leg to achieve the desired ankle trajectory. The design is shown to be adjustable to meet a range of trajectories obtained in an individual's normal gait. Control of the foot position is obtained using a camdriven parallel chain that has the same input as the sixbar linkage. The design of the linkage was carried out using linkage synthesis theory and optimization methods. The result is a one degreeoffreedom system that guides a natural walking movement of the leg and foot. A solid model of the complete device is presented. The results of this research provide a procedure that focuses on the kinematics and mechanical design of a device named the UCI gait mechanism.