A Methodology for evaluating Commercial Off The Shelf parachutes designed for sUAS failsafe systems

Abstract

Many Small Unmanned Aerial Systems (sUAS) are incapable of meeting the safety requirements to provide a sufficient low risk of a fatality while operating above populous areas or gatherings. A recognized mitigation of this risk is a failsafe system that in the event that the sUAS is unable to maintain stable flight, terminates the flight and activates an emergency parachute. This paper proposes a methodology for assessment of Commercial Off the Shelf parachutes for sUAS failsafe systems. The methodology encompasses the evaluation criteria for the selection of parachutes based on a user-defined Maximum Takeoff Weight and the failure scenario tests for assessment of reliability and efficiency. The current standard specification on parachutes for sUAS published by the American Society of Testing and Materials has inspired the failure scenario tests. These failure scenario tests consist of a bench/destructive test and a full power cut test. The multirotor used for test of the proposed methodology is a ∼ 2kg hexarotor. The results suggests the use of one specific parachute. Furthermore, the deployment time and impact energy have been estimated to be 1.2s and 21J, respectively. This impact energy suggests a probability of fatality of less than 0.01. This work is the first step towards selecting and evaluating parachute systems for sUAS. The proposed next steps are the refinement of the assessment of parachutes and increase of parachutes included in the failure scenario tests. Additionally, this will lead to the development of parachute recovery systems for sUAS with manual and autonomous triggering.