Development of Multi Joint Gripper and Its Dexterous Grasping

In our research, we have developed a Gripper with Multi Joint Fingers (MJF) that achieves envelope grasping adapting to shape of objects. In this paper, we discuss grasping motion using two or three MJFs. The MJF has 4 serially connected joints controlled by only two actuators, one for driving all joints at the same time for envelope grasping, the other for controlling the stiffness of every joint all together. This MJG achieves envelope grasping adapting various object shapes without sensory feedback from finger parts. The paper also reports an extended mechanism that enables a smooth transition from a state of pinching object with fingertips to a stable envelope grasping. It also shows the gripper can detect a multiple contact points during envelope grasping with no touch or force sensors on the finger sole.