Abstract
The authors are developing a leg robot as educational tool for physical therapy training. The leg robot can simulate some problems of a knee joint, such as contracture, rigidity, spasticity and so on. However, there are two kinds of differences between actual knee joint mechanism of human and the knee joint mechanism of the previous patient robot. This paper presents a leg robot having a new knee joint mechanism with rolling, sliding and coming off. In the new knee joint mechanism the range of motion of the rolling motion becomes wider, and the coming off motion can be controlled.