Passive Perching with Energy Storage for Winged Aerial Robots

Abstract

Perching in unmanned aerial vehicles (UAVs) offers the possibility of extending the range of aerial robots beyond the limits of their batteries. It has been a topic of intense study for multirotor UAVs. Perching in winged UAVs is harder because a kinetic energy balance has to be struck. Reducing too much energy results in the vehicle stalling and falling. Too much kinetic energy at touchdown could damage the vehicle. Most studies used dangerous pitch‐up maneuvers to manage this balance. This work presents a system that eliminates the pitch‐up maneuver by mechanically capturing and storing kinetic energy at impact. It is validated using a passive mechanical system consisting of a storage mechanism for energy recuperation and a claw for perching on a horizontal rod. The energy stored in the mechanism is then used to unperch. The mathematical model for the recuperation strategy is presented and perching success at various approach attitudes are characterized. The proof‐of‐concept claw recaptures 5% of the kinetic energy during perching. Experiments indicate that the device can successfully perch at a wide range of yaw angles, but requires more precision in roll. We show that our perching mechanism enables the fastest UAV perching to date (7.4 m s−1).

Powerful UAV manipulation via bioinspired self-adaptive soft self-contained gripper

“…Compared to existing rigid grippers for UAVs (15)(16)(17)(18)(19)(20), our soft self-contained gripper is lightweight and eliminates the need for gripper sensors, accurate models, or high-precision control, offering two grasping modes and safe grasping adaptivity. In comparison to existing soft grippers that are shaped like rigid grippers (30-37), our soft self-contained gripper has adaptability and dual-mode grasping capabilities to grasp various objects.…”

“…In the fields of unmanned aerial vehicles (UAVs), aerial transportation and manipulation (1)(2)(3)(4)(5)(6) have drawn more attention because they notably extend the capabilities of UAVs (7), where UAV grasping plays a crucial role (8,9). Numerous studies on UAV grasping (10)(11)(12)(13)(14) have been reported to date, including rigid grippers designed to mimic avian claws (15)(16)(17)(18)(19)(20), achieving grasping by establishing precise dynamic models of the entire system (19,21) or installing a series of sensors on the gripper (20). However, these approaches require complex controllers and heavy rigid grippers.…”

Review of Biomimetic Approaches for Drones

“…Excessive reduction of the kinematic energy causes unstable flight, but high kinematic energy at touchdown will damage the vehicle. Researchers at EPFL [56] developed a mechanism that transfers kinematic energy to other energies for opening and closing the claws and realizes high-speed perching at 7.4 m/s. Researchers at University of Seville [57] developed an ornithopter that uses shape memory alloy springs to reduce the weight and has bioinspired claws that can adapt to any shape.…”

How ornithopters can perch autonomously on a branch

“…In addition, ornithopters require an impact-resilient leg-claw system capable of stopping the fast-moving vehicle and tolerant to flight oscillations. Very recently, Stewart et al succeeded in perching fixed-wing robots from a catapult (23). This research presented impressive grasping capabilities at up to 7.4 m/s, widening the field of operation of fixed-wing robots, but perching from free flight is yet to be demonstrated.…”