The growing use of unmanned aerial vehicles (UAVs) in various sectors has created market demands for drones which can carry heavier payloads and have longer flight endurance. As the endurance of a UAV is highly dependent on the weight of the payload that it carries, drone makers are exploring new and more efficient power sources to produce UAVs that can fly longer while carrying a heavy payload. Previous studies have mainly presented the potentials of fuel cell (FC) as a power source solution for mini to small sized fixed-wing UAVs. The design considerations and performance when implementing the FC system in larger sized UAVs for the purpose of carrying heavier payload and have extended flight endurance has yet been evaluated. This paper describes the design and construction of a 39 kg fuel cell powered heavy-lift medium sized hexacopter and presents the results of its performance, using an analysis of real data from flight tests. It also discusses the possibility of extending flight endurance by increasing the amount of hydrogen fuel using a larger hydrogen tank. In order to provide enough power for the 39 kg medium-sized hexacopter, a 5.2 kw hydrogen fuel cell system was produced by linking two 2.6 kW class power modules. Experiments were conducted to check the performance of the 5.2 kW hydrogen fuel cell system before mounting the system into the hexacopter. Results showed that hydrogen discharge pressure of the hydrogen tanks distributed in Korea cannot cope with the required pressure of 1 bar when loaded with the 5.2 kW power module, so a regulator was used to control discharge pressure. The hexacopter was specially designed to be loaded with the linked FC systems and optimized in terms of weight and structural strength. Structural strength analysis was performed using NASTRAN and PASTRAN to check the design safety margin of the composite skin and the internal structures during structural optimization. Special design considerations were also given to the airflow intake to ensure that the FC system was provided with enough airflow to reach high performance. The flight control system communication and power platform were also modified to adapt to the linked power modules. Flight tests were performed to check the performance and endurance of the UAV. The flight test results demonstrated the feasibility of the designed fuel cell powered heavy-lift hexacopter to perform stable flights. The consumption rate of hydrogen mass was evaluated from the flight test results and the flight time was estimated for the case of a larger hydrogen fuel amount. The consumption rate of hydrogen mass was calculated to be 6 g/min and it was estimated that the flight time could be increased by 6 min by using a larger hydrogen tank to store an additional 36 g of hydrogen fuel.
Design and Performance Analysis of a Fuel Cell Powered Heavy-Lift Multirotor Drone
Lect. Notes Electrical Eng.
Asia-Pacific International Symposium on Aerospace Technology ; 2021 ; Korea (Republic of) November 15, 2021 - November 17, 2021
The Proceedings of the 2021 Asia-Pacific International Symposium on Aerospace Technology (APISAT 2021), Volume 1 ; Chapter : 20 ; 269-282
2022-08-31
14 pages
Article/Chapter (Book)
Electronic Resource
English
Analysis of Preliminary Design Requirements of a Heavy Lift Multirotor Drone for Agricultural Use
DOAJ | 2017
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