Hiroshi Yoshinada

Design and experiments for a coupled tendon-driven manipulator

The authors describe the operation of a tendon-driven manipulator, the CT ARM-I, which has a tendon traction force transmission mechanism in which the pair of tendons that drive a joint are pulled from base actuators via pulleys mounted on the base-side joints. The mechanism makes the most of the coupled drive function of the tendon traction forces and thus enables the lightweight manipulator to exhibit enormous payload capability. The manipulator has a solid structure and is inexpensive to manufacture because of its mechanical simplicity. Experiments demonstrate that the CT ARM-I has an active compliance arm and offers payload capability superior to that of conventional manipulators.<<ETX>>

Development of a hyper-redundant multijoint manipulator for maintenance of nuclear reactors

A tendon-driven manipulator, the CT Arm, has a specific tendon traction transmission mechanism, in which a pair of tendons for driving a joint is pulled from base actuators via pulleys mounted on the based-side joints. The mechanism makes the most of the coupled drive function of the tendon tractions and thus enables the lightweight manipulator to exhibit enormous payload capability. By this tendon-driven mechanism, a multijoint manipulator with super-redundant degrees of freedom could be realized, which is suitable to the maintenance of nuclear reactors. In this article, we introduce the CT Arm and discuss the possibility of generating a multijoint maintenance manipulator for nuclear reactors, which must have super-redundant degrees of freedom. A position-coordination approach for a hyper-redundant manipulator to carry tools or inspection equipment passing through a hole to a work location in a nuclear reactor is also proposed. Computer simulation has been used to show the validity of the hyper-redundant...

CT ARM-I: coupled tendon-driven manipulator model I-design and basic experiments

A nine-degree-of-freedom multijoint manipulator called the CT ARM-I has been developed. The CT ATM-I is based on the concept of coupled drive and the connected differential mechanism, and thus the force for lifting a payload does not concentrate on one actuator but is distributed among all actuators. This manipulator has a specific tendon traction force transmission mechanism in which a pair of tendons for driving a joint are pulled from base actuators via pulleys mounted on the base-side joints. The mechanism uses the coupled drive function of the tendon traction forces and thus enables the lightweight manipulator to exhibit high payload capability. Through the experimental study, it was demonstrated that the CT ARM-I has an active compliance arm and offers payload capability far superior to conventional designs.<<ETX>>

Seawater hydraulic actuator system for underwater manipulator

A seawater hydraulic actuator system for a subsea robot has been developed. The system consists of a high pressure axial piston pump, flow control servovalves and actuators which transform controlled flow into motion, and it is very effective in miniaturizing a subsea robot. In order to confirm overall characteristic of this power systems, a prototype telemanipulator for underwater work has been also developed. A manipulator control system is based on a master-slave method with some telepresence technique to provide easy operation of a manipulator. Through running experiments in underwater manipulation, overall characteristic of the seawater hydraulic system and working performance of the prototype subsea manipulator have been confirmed to be good enough for practical use.<<ETX>>

Development of coupled tendon-driven multijoint manipulator

A coupled tendon-driven manipulator, CT arm, is presented. In its tendon traction force transmission mechanism, the pair of tendons driving a joint is pulled by base actuators via pulleys mounted on the base-side joints. The mechanism uses coupled drive function of the tendon traction forces and thus exhibits a large payload capability for such a light-weight manipulator arm. CT arm has a solid structure and can be manufactured inexpensively because of its mechanical simplicity. Through experimental simulation, it is known that CT arm has the structure of a variable compliance arm and has an unusually large payload capacity.<<ETX>>

Bi-Lateral Manipulator for Construction Works

In this paper, we describe the bi-lateral manipulator for construction works, in which the large scale manipulartor with remote operation is needed. Through the experiments, it was verified that the bi-lateral master-slave manipulator enables sensitive force control, smooth positioning and easy operating. The availability for construction works has been verified by the applications for two works, troweling concrete in the tunnel, and erecting shield-segments.