A model of a paralyzed hand gripping and lifting an object was developed using anaesthetized cats. Functional neuromuscular stimulation (FNS) applied to the ankle plantarflexor muscles caused the footpad to press against and grip an object. Electroneurographic activity (ENG) activity generated by skin mechanoreceptors in the footpad was recorded with a cuff electrode implanted on the tibial nerve. Sharp bursts evident in the ENG signaled any slips between the object and the skin. This information was used in an event-driven controller that allowed the FNS system to compensate for slips. In this way an "artificial gripping reflex" was implemented that compensated automatically for internal changes (fatigue) and the external perturbations (increased load, changed frictional coefficient). This control scheme proved to be robust and is proposed to be applicable for restoration of precision grip in paralyzed humans.
展开▼
