Biomimetic control of FES reaching

We are developing a biomimetic controller to restore BION-assisted reaching movements to quadriplegic patients. The controller has a hierarchical structure similar to that of the central nervous system (CNS), mimics the biological control circuits in the spinal cord and integrates with the patient´s residual voluntary movements. To demonstrate the feasibility of the proposed control strategy, we have examined one of its most critical components, i.e. the ability of subjects to produce adequate voluntary command signals to drive the functional electrical stimulation (FES) control of paralyzed joints. Normal subjects use their shoulder movements to drive a simulated lower arm in a virtual reality environment (VRE) to reach targets in 3D workspace of the arm. The preliminary results show that the type of the voluntary command signal and the type of FES control strategy have significant effect on the successful completion of the reaching tasks, the reachable workspace and the learning rate.