抄録
This paper proposes a linear motion mechanism for a robot gripper that can exert a large grasp force. A robot gripper requires speed when opening and closing its jaws, and force when grasping an object. The proposed linear motion mechanism can drive its output quickly to an object and can generate a large grasp force by using a lever. The mechanism has two feed screws with different pitches along one screw shaft. Initially a gear is fastened on the feed screw with the smaller pitch to rotate the shaft. The feed screw with the larger pitch enables quick motion of the output nut. After the output makes contact with an object, the rotation of the shaft stops. By further driving the gear, it becomes loosened and begins to move axially by the feed screw. The gear pushes the lever, which generates a large fingertip force. We have developed an 86g gripper with this mechanism and experimentally verified that it can grasp objects of various sizes and can exert a large grasp force over 200N. It is also experimentally verified that the gripper can grasp and ungrasp an object reliably over 5000 times if machine lubricant is properly supplied.
