A Two-Fingered Independent Gripper Capable of High-Speed Contact Grasping Using Low-Friction Geared Electric Motors

Abstract

Most current industrial robots are composed of rigid links and joints, and thus, are not good at tasks involving physical contact. In order to make wide use of the industrial robots in the future, it is important to allow high-speed motion with physical contact in the presence of environmental recognition errors and positional accuracy errors of robots. Therefore, in this paper, a two fingered robot gripper was proposed as a solution to the problem of speeding up the contact operation from both hardware and software perspectives. On the hardware side, two geared electric motors capable of backdriving easily with low external force were adopted to this gripper. On the other hand, in terms of software, the proposed gripper does not require the robotic arm to stop for grasping, therefore, the takt time of the operation is reduced by continuously giving the end-effector position command. It was experimentally confirmed that the gripper can achieve high-speed grasping by utilizing backdriving of the actuators. The torque is simply turned off upon contact and turned on simultaneously with the upward motion of the robotic arm. From the experiments, it was confirmed that the developed gripper can grasp various objects without reducing the robotic arm speed.