Biomimetic EMG-prosthesis-hand

The purpose of this study is to develop a myoelectric prosthetic hand that simulates fundamental dynamic properties of the neuromuscular control system of human hand. In particular, this prosthetic hand mimics the property that both muscle viscoelasticity and gain of the stretch reflex vary linearly with the activity of muscle. Those nonlinear properties of the neuromuscular control system were realized by using a position control system of the finger movement, force feedback and variable gain which was modulated by amplitude of rectified and smoothed EMG signals. The prosthetic hand consisted of a processing unit of surface EMG signals, a digital servo system of DC motor and a mechanical hand of one-degree-of-freedom with three fingers. Usefulness of the developed prosthetic hand was shown in myoelectric control experiments with an amputated subject. Both the finger-angle and the stiffness of the hand were voluntarily controlled with EMG signals and soft objects were grasped smoothly