Balloon Pin Array Gripper: Mechanism for Deformable Grasping with Two-Step Shape Adaptation

Pin array grippers with many slidable pins arranged in parallel can adapt to complex object shapes. However, in conventional methods that move the pins only in specific directions, the conditions for successful grasping are limited by the shape, position, and orientation of the target object. In this study, we propose a balloon pin array gripper capable of inflating flexible balloons in the radial direction of each pin. This method makes the soft wrapping of objects possible from multiple directions in a two-step shape adaptation: pin array sliding and balloon expansion. A design method for combining balloons with a pin array, including an air supply system, was devised. Experiments and tests with the prototype demonstrated the validity of the concept.