Sheet-Based Gripper Featuring Passive Pull-In Functionality for Bin Picking and for Picking Up Thin Flexible Objects

This letter presents a novel versatile parallel gripper equipped with a sheet-embedded belt that enables passive pull-in operations. The belt is wrapped around each fingertip of the gripper, and it passively moves with the opening and closing motions of the gripper. The fingertip is made of plastic, and it is deflected when a grasping force is applied to the fingertip. This deflection enables the belt to roll up with the closing motion of the gripper, thereby passively pulling the grasped workpiece towards the gripper. This pull-in mechanism is effective in performing bin-picking tasks as well as in picking up thin, flexible objects one at a time. The softness of the sheet-embedded belt surface provides high adaptability to the shape of the object; therefore, many kinds of workpieces can be picked up. The effectiveness of the proposed gripper is experimentally demonstrated in this study.