Design of feedback control strategies for an arm neuroprothesis combined with an exoskeleton

For restoration of reaching function in patients with upper motor neuron lesion a noval control strategy for a neuroprosthesis was developed within the EU project MUNDUS. By applying controlled Functional Electrical Stimulation (FES) to the shoulder deltoid muscle and the biceps, functional arm movements can be achieved. An exoskeleton with three DOF partially compensates for gravitation and allows to lock joint angles for holding purposes. This is exploited by a feedback control strategy to reduce muscular fatigue. The control algorithm that sequentially controls the joint angles according to a given reference one after another is designed. The feasibility of the approach was demonstrated by successfully applying the strategy to one spinal cord injured (SCI) subject.