Abstract
We developed a motor-driven joint exerciser for the hip and knee incorporating three-dimensional load sensors in the thigh and calf supports of the machine. The machine can memorize and replay exactly the same exercise as therapists teach with three degrees of freedom of motion in the median plane. The previous investigation focuses on the virtual mechanical impedance control which enables soft movement like the exercise for the spastic joints by the human therapists. In this study we proposed the new controls adding the integral term to the equation for the impedance control so that the machine could stretch the stiff joint overcoming resistive joint force. Numerical calculation could show the new controls worked well both for the stiff and spastic joints. We installed the new controls in the machine, and demonstrated stretching effects of the controls on the stiff hamstrings muscles.
