Perching and Grasping Mechanism Inspired by a Bird’s Claw

Abstract

In nature, birds can freely observe and rest on the surface of objects such as tree branches, mainly due to their flexible claws, thus this paper is inspired by bird perching and shows two imitation bird claw perching grasping mechanisms in the shape of “three in front and one at the back”. One is articulated, the other is resilient, the difference being that the former has a pin-articulated claw structure and uses a double fishing line to perform the grasping and resetting action, while the latter uses a resilient linking piece, a single fishing line and resilient linking piece to perform the grasping and resetting action. To verify the grasping effect, experiments were designed to grasp objects of different shapes and maximum grasping weight load. The results show that the two types of perching grasping mechanism can reach a large degree of toe bending, have good passive bending deformation ability, can grasp different types of objects, including the articulated type has a stronger deformation ability, and can grasp branches with a diameter in the range of 12.5–55.8 mm. The elastic reset type is smoother than the articulated type toe bending curve, and the maximum graspable object weight is about three times the overall weight of the grasping mechanism. The maximum gripping weight is about three times the overall weight of the gripping mechanism and the load capacity is about two times that of the articulated type.