Fuzzy-control of a hand orthosis for restoring tip pinch, lateral pinch, and cylindrical prehensions to patients with elbow flexion intact.

This study examines, through simulation, the use of fuzzy logic as a feasible control scheme for a hand orthosis that can restore fingertip pinch, lateral pinch, and cylindrical grasps to individuals suffering from C5-C7 spinal cord injuries. A simplified hand orthosis model, consisting of four fingers and a thumb, was derived for the purpose of planning appropriate grasp trajectories and for validating the fuzzy logic control architecture. For comparison a proportional-plus-integral-plus-derivative (PID) controller was also designed. Fuzzy logic is advantageous for this system since it eliminates solving coupled nonlinear equations of motion. For the various grips, the fuzzy controller produced better performance than the PID controller.