Crash-perching on vertical poles with a hugging-wing robot

TL;DR

This paper introduces a passive, wing-morphing UAV design that enables crash-landing and perching on vertical poles and trees, simplifying the process compared to complex control systems.

Contribution

The study presents a novel passive reorientation and perching method using dual-purpose wings inspired by animals, allowing simple crash-landing on various vertical structures.

Findings

Reorients at impact angles above 15° and speeds of 3-9 m/s

Successfully perches on poles larger than 28% of wingspan

Achieved 71% success rate in crash-perching on tree trunks

Abstract

Perching with winged Unmanned Aerial Vehicles has often been solved by means of complex control or intricate appendages. Here, we present a simple yet novel method that relies on passive wing morphing for crash-landing on trees and other types of vertical poles. Inspired by the adaptability of animals' and bats' limbs in gripping and holding onto trees, we design dual-purpose wings that enable both aerial gliding and perching on poles. With an upturned nose design, the robot can passively reorient from horizontal flight to vertical upon a head-on crash with a pole, followed by hugging with its wings to perch. We characterize the performance of reorientation and perching in terms of impact speed and angle, pole material, and size. The robot robustly reorients at impact angles above 15{\deg} and speeds of 3 m/s to 9 m/s, and can hold onto various pole types larger than 28% of its wingspan in diameter. We demonstrate crash-perching on tree trunks with an overall success rate of 71%. The method opens up new possibilities for the use of aerial robots in applications such as inspection, maintenance, and biodiversity conservation.