Prototype of a Continuous Passive Motion Device for the Knee Joint with a Function of Active Exercise

In this study, an active exercise function was added to a continuous passive motion device, which is widely used in rehabilitation therapy for function enhancement. The objective is to reduce physical overwork on the part of physical therapists and promote self-rehabilitation in patients. Impedance control based on position control was applied to provide active exercise load. Various active exercise loads are required to reproduce daily life muscle activity. Accordingly, a friction load model was introduced in the impedance control system. The effects of increasing the types of active exercise loads were evaluated by analysis of muscle activity during experimental tests, and a new muscle activity that could not be attained by the conventional spring-mass-damper load model was confirmed.