Optimal Synthesis of a Four-bar Linkage for Human Gait Rehabilitation

Abstract

Linkage mechanisms are major parts of robotic gait rehabilitation systems. Four-bar linkage mechanisms are the basic forms of linkage mechanisms synthesized for human gait path generation. The relationship between the limiting position characteristics of linkages and gait trajectory phases need to be analyzed due to the timing requirements of gait training. However, it is seldom mentioned among the available literatures. A new synthesis method and genetic algorithms based optimization of the basic linkage mechanism is presented in this paper, which contains: (1) the desired human gait path curve, (2) the new synthesis method of the basic linkage mechanism, (3) optimization and simulation of the basic linkage mechanism. The coupler curve generated by the mechanism designed with this process is shown to match well with the desired gait trajectory, illustrating the feasibility of the presented method.