Computational Design of a Bird-Inspired Perching Landing Gear Mechanism

Abstract

To support the design of a mechanism with two opposing, underactuated, multi-segmented feet that enables a small UAV to grasp and perch upon a branch or similar structure, a hybrid empirical-computational model has been developed that can be used to predict whether the mechanism can kinematically grasp structures with a range of cross-section shapes and sizes in various orientations and to quantify the forces exerted by the grasp. The model, based on experimentally-determined parameters, relates the curvature of the feet to the displacement and tension of the cable tendon which is related in turn to the weight of the UAV. The working principle of the landing gear follows the anatomy of birds that grasp and perch as tendons in their legs and feet are tensioned. Results demonstrate how the model can be used to simulate and evaluate grasping in order to determine the size and weight of a UAV for landing and perching upon a range of target structures.