An Avian-inspired Mechanism for UAVs Perching and Grasping

Multirotor unmanned aerial vehicles (UAVs) are constrained by limited battery capacity, which makes it challenging to support long-duration and high-frequency missions. A widely adopted strategy to conserve energy or enable mid-mission charging is to allow UAVs to perch on various surfaces. Inspired by the structure and function of avian claws, this paper presents a novel bionic perching mechanism designed to overcome the limitations of existing UAV landing gear, such as the lack of active control and slow grasping response. The proposed mechanism includes a series of innovative designs, such as a zygodactyl toe arrangement and a tendon-spring-based passive stabilization system. A passive claw-closing mechanism is developed to enable automatic grasping and ensure stable perching, which is actuated by changes in tendon paths upon contact. A spring-trigger system is presented to facilitate energy pre-storage and rapid release, which equips the system with active grasping capabilities. Multiple experiments are conducted to evaluate the performance of perching and grasping. Experimental results on perching show that the mechanism has a prominent capability in shock absorption and stability, with secure perching on tree branches under a load of 600 grams. Grasping tests further verify the mechanism’s strong gripping performance, with a 95% success rate.