History of Robotics Research and Development of Japan2005ManipulationLoad-Sensitive Continuously Variable Transmission for Robot Hands

Takeshi TakakiTokyo Institute of Technology
Toru OmataTokyo Institute of Technology
We proposed a load-sensitive continuously variable transmission (CVT) for finger joints. Fingers of robot hands require force when grasping an object and speed when opening and closing. Therefore a CVT is ideal to improve the power transmission of a finger joint. Existing friction CVTs are too big and heavy to be installed in a finger joint. By focusing on the fact that finger joints do not necessarily rotate 360 degrees, this paper presents a remarkably simple and small load-sensitive CVT consisting of a five-bar linkage and a torsion coiled spring. Experimental results show that the CVT can increase its reduction ratio from 0.5 to 3.3 in response to a load. We have developed a two-finger gripper with the CVTs, which can grasp an object powerfully and manipulate quickly. These motions would be impossible without the CVT. 20th RSJ Best Paper Award in 2006.
Prototype of the CVT
100g-100N finger
2-DOF finger

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