PALGRIP-Twin for Handling a Piece of Fabric

A pick-and-place operation of fabric pieces is a fundamental task in automated garment manufacturing. For easy installation of the robotic hand, we developed the Passive Actuator-Less Gripper (PALGRIP), which enables pick-and-place operation of a piece of fabric without the use of actuators. Maintaining fabric flatness during transport is essential for high-precision operations and typically requires a dual-arm system to grasp at least two points on the piece of fabric while keeping a small tension on the fabric. In this paper, we propose PALGRIP-Twin, a novel passive gripper that can hold two points of a fabric piece using a single manipulator, enabling the fabric to be lifted and transported in a spread state without any actuators. PALGRIP-Twin consists of two passive pinching mechanisms and one self-locking mechanism, while PALGRIP consists of one passive pinching mechanism and one self-locking mechanism. By placing two passive pinching mechanisms on both sides of the self-locking mechanism, the distance from the robot endpoint to the fingertips of the gripper can be made small. We demonstrate the effectiveness of PALGRIP-Twin through experiments, confirming its ability to perform pick-and-place tasks while maintaining fabric flatness and ensuring reliable separation of a fabric from a fabric stack.