Proposal of a SkilMate finger for EVA gloves

It has been pointed out that the hard structure of an EVA glove deteriorates efficiency of tasks in the space environment. We also found a claim that an EVA glove did not allow an astronaut to acquire contact information at the fingertips. In the study, we proposed a SkilMate Hand for space EVA gloves which has both a tactile media and a power assist devices. We locate SkilMate in a wider framework of wearable intelligent machines which assist in affording such working surroundings that they can exhibit their skills in spite of their necessity for wearing special suits typically in hazardous environments. The paper focuses on the development of a finger system of a SkilMate Hand, and begins with determination of the design guidelines through analyses from an interview with an astronaut. To improve the task efficiency, we manufacture a power assist device which compensates the bending moment exerted at a human finger joint utilizing an ultrasonic motor. We show the structure and the control strategy of the motor drives. To overcome the second problem of tactile insensibleness, we produce a tactile media device which is composed of a slip sensor element on the outer side and a vibrotactile display element on the inner side of a SkilMate Hand. Transduction characteristics of both pressure sensitive conductive rubber and piezo-rubber are experimentally examined in the low temperature region. Finally, piezo-rubber is chosen to be used as a slip sensing transducer.