An underactuated gripper to unlatch door knobs and handles

This paper describes the development of an underactuated gripper designed to unlatch doors knobs and handles. The challenge was to create a mechanism that could manipulate a variety of door knobs and handles while using only one motor in order to create a low cost device. The final design evolved by exploring the limitations in the performance of an initial gripper prototype. In this paper, the cause of failure for the changes made in the second design. The final design was capable of twisting door knobs and handles in clockwise and counter-clockwise directions. It had a collet-cone shape for compliance gripping and centering, and it utilized one motor for both gripping and twisting actions. The discussed gripper was developed for the assistive technology domain; however, this gripper mechanism could be utilized in a wide variety of robotic domains that exits today.