Life-like Control for Neural Prostheses: "Proximal Controls Distal"

We describe the model and implementation of the hierarchical hybrid method for controlling of the lower-arm (pronation/supination and elbow flexion/extension) in humans with disabilities. The control follows the strategy found in able-bodied humans where the movement is planned based on the task and the most distal part of the arm; yet, the command starts from the most proximal segment. The controller uses a black box of the movement and relies on temporal and spatial synergies. The driving signals are the shoulder flexion/extension velocity and acceleration, the outputs are four stimulation patterns for the control of elbow flexion/extension and pronation/supination. The operation is discrete at the voluntary and coordination levels, and continuous at the actuator level. The repertoire of movement that were considered was limited to a set of typical daily activities within the normal workspace in the sitting position only. The main application of this control is the therapeutic electrical stimulation in post-stroke hemiplegic patients