Verification of erroneous operation of myoelectric prosthesis with shear force and pressure sensor

Abstract

The purpose of this research is to verify the cause of malfunction of a myoelectric prosthesis. Subjects were 14 healthy adults wearing simulated artificial hands. Shearing force and pressure at elbow flexion and extension were measured with a thin sensor. Three sensors were affixed in the socket : 1) Outer electrode installation position (outer part), 2) 2.5 cm above the olecranon (above the olecranon), and 3) Inner electrode installation position (inside part). Shear forces at elbow flexion and extension had low values. Therefore, it was difficult to conclude that malfunction occurred due to the electrode being displaced on the skin. On the other hand, the pressure was significantly lower in the inner part than outer part. This result showed that the inner part was liable to cause poor contact with the stump compared to the outer part. It is suggested that this likelihood is one of the factors behind the malfunction of a myoelectric prosthesis.