Richard F. ff. Weir, PhD, Principal Investigator
Dilip Thaker, Instrument Maker Funded by: Veterans Administration Merit Review Proposal A2364R  The second project is Merit Review Proposal A2364R: "Development of a Four Degree-of-Freedom Hand", a three year project started in April 2000. This project is to develop a multiple degree-of-freedom externally-powered prosthetic hand for persons with amputations proximal to the wrist. This design is limited to those degrees-of-freedom necessary to generate tip, palmar, lateral and cylindrical grasp patterns on the assumption that to be clinically viable it is impractical to expect to reproduce all the degrees-of-freedom of a natural hand.
The mechanism uses three motors in the hand and two motors for the wrist. One motor to drive a single DOF thumb that operates along the preferred 45 degree plane; one motor to drive the index finger; one motor to drive the middle, ring and little fingers as a unit; one motor to provide wrist extension/flexion and one motor to provide wrist rotation. Fuzzy logic is used to discriminate between multiple surface myoelectric control signals. Fuzzy membership functions are used to detect EMG onset while an inference engine (or rules) provide pattern recognition to classify user intent. The membership functions and the inference engine are generated automatically using algorithms based on previously recorded EMG signal statistics and on fuzzy clustering techniques. | 
