To successfully incorporate human skills into a wearable robot, it is required to design its joint mechanism so that it does not interfere with the human skills. From this viewpoint, this paper first addresses six design goals for the joint mechanism. Based on the result of preliminary examination for two well-known mechanisms, a new 6-DOF mechanism referred to as the Wearable HEXA mechanism is proposed. This is based on the HEXA, which has been originally developed as a high-speed manipulator. Detail of its design process is given, and evaluation of a trial mechanism manufactured along the design process is also reported.

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.

Problems of modeling and controlling the 3D motion of a flexible space robot is discussed. By concentrating the mass at the joint and neglecting the link mass, the model of the flexible robot is derived based on Lagrange dynamics and rigid and flexible coordinates transformation. For further frequency analysis, the obtained linear model is modified so that state variables of the model are independent. The model has been verified by simulation results and experiments using the laboratory robot. The resultant model is simple and easy to be executed efficiently in the real-time control. Control problems are then discussed based on the derived model. A control scheme for adaptation to variations of dynamics due to configuration changes is presented and has been implemented in a space flexible robot.>