抄録
Myoelectric hand is required that enabling user to achieve various kinds of Activities of Daily Living (ADL). Above all, grasping behavior which accounts for 85 percent of ADL is necessary to achieve first. In grasping behavior, human controls the five fingers dexterously. In the five fingers' movements, the most important movements are opposition-apposition and adduction-abduction of thumb for grasping behavior. Therefore it is necessary that myoelectric hand has the two movements of thumb. Actually, there are some myoelectric hands which are being marketed. But these are so heavy that wearing those hands are a burden to users. To solve that problem, myoelectric hands used tendon driven which enable to make hands light have been being developed now. But, previous thumb mechanism is short for range of motion and torque. So it does not achieve enough kinds of grasping behavior. In this study, we developed a coupled-tendon driven thumb mechanism which can do opposition-apposition and adduction-abduction. This mechanism does opposition-apposition by using cylindrical guide set on opposition axis to enable to balance two wires. And this one dose adduction-abduction and flexion-extension by towing three links set on the link which moves around opposition axis perpendicularly from palp of hand. A prototype confirmed that proposal mechanism is enough to light to use as myoelectric hand and has range of motion the same as human. Moreover, prototype confirmed that it has more torque of adduction up to 670% than previous mechanism and achieves grasping behavior used in daily living.
