Passive Transformable Fingertip to Augment Tableware Grasp Capability

This paper suggests a transformable fingertip that can make a gripper grasp tableware of various sizes and shapes. Our fingertip can enhance both the graspable range of the gripper and the grasp success rate in various tableware. A gripper design for tableware is difficult due to constraints such as limited graspable region by food on the objects and a mechanical disadvantage to making the gripper large to grip tableware of various sizes. We overcame this challenge with a novel fingertip mechanism that can rotate its fingers. The gripper can take advantage of multiple contact surfaces, the shape of which is customized for grasping objects of various widths and shapes by rotating the fingers. We mounted our prototype fingertip on a commercial gripper and compared it with a conventional fingertip. As a result, we could observe that the proposed fingertip enhances not only the gripper's grasp success rate but also its graspable range.