Three-dimensional dynamic surface grasping with dry adhesion

Abstract

Most robotic grasping research focuses on objects that are either not large in comparison to the gripper or have small graspable features; however, there are important applications that involve large flat or gently curved surfaces. Examples include robots that grasp the solar panels of space craft, handle large panels in manufacturing, or climb or perch on surfaces. We present a solution for grasping such surfaces consisting of groups of tiles coated with a controllable gecko-inspired adhesive. The tiles are loaded with two sets of tendons: one for distributing the forces evenly while grasping and the other for release. The gripper is passive and can attach and detach with little effort so that it does not disturb either the robot or the object to be grasped. The maximum gripping force in the normal direction can be over 1000 times greater than the required detaching force. The gripper is also fast, allowing a flying quadrotor to attach to a surface milliseconds after the tiles make contact. We present a model of the gripping mechanism and use the model to design the layout of the tiles to best support anticipated normal and tangential loads.