Hybrid Energy Solutions for Remotely Piloted Aircraft Systems

Unmanned aerial systems and drones are becoming more widespread, and there is a rapid development of new technologies, fascinating concepts, and useful services. Drones have some clear advantages with their small size, silent operation, and payload capacity for cameras and other sensors or small deliveries. Because of this, drones can perform operations previously carried out by helicopters and a new type of operations that previously has not been practically possible or economically feasible using helicopters. Typical operations where drones can be used are search and rescue, inspections, emergency support, rapid deliveries from A to B, or 3D-scanning of urban environments or construction sites. Limited endurance is a central limitation for increased commercial and industrial use of drones. One approach to extend the endurance is to use a power plant that is based on fuel cells and hydrogen. To achieve that, the system must provide more energy per mass than batteries can. This introduces some unique challenges. Some previous work has been done for integration on small fixed-wing UAVs, but there is much less experience on multirotor drone integration. Through the project, a prototype has been developed based on the Staaker BG-200 drone, a product manufactured and sold by Nordic Unmanned. It has a 2 kW fuel cell system, a 7.2L pressure vessel with hydrogen, and a take-off mass of 21 kg. The first test flight was successfully completed December 9th, 2020. Four papers have been produced that approach various aspects of integration and use of fuel cells to power multirotor drones. They answer questions regarding the threshold for when a fuel cell powered drone will provide better endurance than a battery-powered one, what the prototype performance is, what the prospects of further adoption are, and how the performance can be further improved. The work looks at regulatory aspects, technical maturity, and operational challenges. Altogether the research establishes knowledge about how fuel cells can be used to extend multirotor endurance, and has provided a solid foundation for further research and commercial development.

- Det er utviklet en prototype av en multirotor drone med brenselceller som er demonstrert og flytestet. - Prosjektet har etablert en solid basis for videre forskning og kommersiell utvikling. - Gjennom å bli et av de første luftfartøyene med hydrogen og brenselceller til å få flytillatelse fra Luftfartstilsynet, har prosjektet bidratt til en viktig milepel inn mot å oppnå mer miljøvennlig luftfart. - Universitetet i Stavanger har fått innblikk i et nytt og fremtidsrettet fagfelt.

As Remotely Piloted Aircraft Systems (RPAS) are becoming more widespread and efforts are being made for industrial utilization of such systems, flight time is a key aspect. To solve demanding operations in urban arctic environments, the flight time must be increased from the current standards. This PhD project is a collaboration between University of Stavanger (UiS) and Nordic Unmanned AS (NUM), and aim to minimize the weight of, and maximize the energy available for a Remotely Piloted Aircraft System. That will be done through using advanced materials in the structural design, optimizing design parameters, implementing advanced fuel cell and battery technology, and optimizing the performance in challenging operational conditions. The goals of the project are to extend the flight time compared to battery alone performance, and to demonstrate a prototype with innovations from the research. The main challenges are expected to be sufficient power and energy capacity, and integration through making the system compact, robust, reliable, and simple to use.