Collision Recovery Control of a Foldable Quadrotor

TL;DR

This paper introduces a foldable quadrotor with integrated mechanical compliance that can withstand collisions and recover autonomously, enhancing UAV safety during critical missions.

Contribution

A novel foldable quadrotor design with integrated torsional spring compliance enabling collision resilience and simple recovery control algorithms.

Findings

Spring-damper design reduces rebound velocity

Enhanced collision recovery compared to rigid quadrotors

Successful flight tests demonstrating collision endurance

Abstract

Autonomous missions of small unmanned aerial vehicles (UAVs) are prone to collisions owing to environmental disturbances and localization errors. Consequently, a UAV that can endure collisions and perform recovery control in critical aerial missions is desirable to prevent loss of the vehicle and/or payload. We address this problem by proposing a novel foldable quadrotor system which can sustain collisions and recover safely. The quadrotor is designed with integrated mechanical compliance using a torsional spring such that the impact time is increased and the net impact force on the main body is decreased. The post-collision dynamics is analysed and a recovery controller is proposed which stabilizes the system to a hovering location without additional collisions. Flight test results on the proposed and a conventional quadrotor demonstrate that for the former, integrated spring-damper characteristics reduce the rebound velocity and lead to simple recovery control algorithms in the event of unintended collisions as compared to a rigid quadrotor of the same dimension.