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Two »Songbirds 150« from Germandrones were purchased as part of the ALBACOPTER^® research project to test and validate innovative attitude control systems, autopilots, sensors and energy management systems. The VTOL (Vertical Take-off and Landing) capable aircraft have a wingspan of 3 m and can carry a payload of up to 4 kg. This provides sufficient power for additional on-board computers and further sensors. As planned for the ALBACOPTER^® 0.5 aircraft, these drones also have swivel drives, making research results adaptable and easy to use. In order to be able to control the drones, four remote pilots from Fraunhofer IEM and IVI took part in a training course lasting several days. On Aug. 26, 2021, the aircraft were handed over to the two institutes in Berlin Moabit. 

Since the project's kick-off in January 2021, the six participating Fraunhofer institutes IVI, ICT, LBF, IOSB, IEM, IMS have contributed detailed work to the ALBACOPTER® 0.5 demonstrator concept and have designed the first models.

All three variations were evaluated on the basis of different criteria and their performance was compared. In close cooperation with industry partners, the advisory board and the participating institutes, additional investigations will be carried out and an implementation concept compiled. This implementation concept will have the following pre-defined features:

• ca. 7 m wingspan, ca. 3 m hull length
• Cargo box with 25 kg capacity, ca. 120 liters
• Take-off weight 125 kg
• Swivel-mounted drive units
• 5.5 kWh LiPo batteries
• SpaceFrame hull architecture
• Wings executed in conventional composite-monocoque construction
• PX4 flight control with risk management

Additional work is carried out simultaneously concerning the development of energy supply and drive system, as well as realizing autonomous flight.

During the virtual demonstrator meeting on July 21, 2021, the advisory board and industry partners had the opportunity to gain information on the current state of the project and were invited to contribute their own ideas and advice. Many exciting new approaches and potential future collaborations were generated by the discussions. 

The demands made of reliable environmental sensors are as diverse as the application areas of VTOL systems. Only robust object detection around aircrafts can serve as the foundation for safe flight control preventing collisions.

For this purpose, the Fraunhofer researchers work across disciplines and thus contribute effectively to the progress in each of their individual disciplines: Some examples of this are optical sensor technologies for distance measuring, digital twins, Ai algorithms for object detection, as well as solutions for data fusion and integration.

Within the ALBACOPTER^® project, the experts on sensors have joined to solve the task of achieving »low sensor weight with highest sensor performance and robustness«.

The newest LiDAR photo detector developed by Fraunhofer IMS (see image), for example, will be used within the project as a forward-looking prototype. With the help of this intelligent »light collector«, it is possible to record up to single photone events, which allows the researchers to create comprehensive distance senors. In terms of software, Fraunhofer IVI works on algorithms for the spherical visualization of camera data to realize environment recognition.

Due to the flexibility of being able to replace sensors by their respective newer generations, which is pursued within the ALBACOPTER^® project, a unique environment sensor experimenting platform will be created for the VTOL application field.

Within the scope of the ALBACOPTER^® Lighthouse Project, novel drive systems for eVTOL are being designed, demonstrated and tested. While direct drive systems are often used in the field of eVTOL today, the research partners of the  ALBACOPTER^® Lighthouse Project have deliberately chosen an alternative path towards realizing drive systems with higher performance. Their aim is to develop a safe drive system with a higher weight-specific continuous performance. During the current stage of the project, different solution approaches have been considered. »By now, we have investigated and evaluated various drive topologies, and we are seeing that our approach can have clear adavantages« announces Dr. Lars Fredrik Berg, project manager for energy storage systems and drive engineering. The preferred concept uses a high-speed synchronous machine combined with a multi-level spur gear unit in order to fulfill the high functional requirements made of the drive system. »Currently, we are in the end stages of the conceptual phase and will soon begin constructing the drive unit in detail« reports Dr. Berg. In addition to developing the drive unit, the Karlsruhe researchers are also designing a test stand for the realistic testing of eVTOL drive systems in the performance class up to 450 kW.

Secondary battery cells allow highly reversible intercalation and de-intercalation processes. Therefore, they can be charged and discharged for a very high number of times. After a certain time of use, however, degradation mechanisms nevertheless start to affect the cells and can lead to a loss of performance or even exothermic reactions. For this reason, Fraunhofer LBF scholars conduct targeted research into the behavior of different cells and power connectors during charging and discharging processes under very high currents that can occur, for example, during flight phases with special demands. A specific lab setup featuring secondary cells connected in series (see image) is being built for the purpose of investigating the temperature progression of cells and power connectors. The results will present data relevant to the reliable operation of eVTOL energy storage systems that has often been insufficiently considered until now.

January 2021 saw the kick-off of the Fraunhofer ALBACOPTER^® – Experimental Vertical Take-Off and Landing Glider Lighthouse Project. 

Conquering the Third Dimension within the ALBACOPTER^® Lighthouse Project

The Albatross is one of the most effective glider birds. Its superb maneuvering capability and effortless gliding for thousands of kilometers on air streams is highly admirable. A consortium consisting of six Fraunhofer Institutes aims to adopt this principle from nature by developing the ALBACOPTER^® , an aircraft with fantastic gliding characteristics and the ability to take off and land efficiently. The official kick-off meeting was held as a virtual event on March 8, 2021.

Stay informed about all details concerning the Fraunhofer ALBACOPTER^® Lighthouse Project – including news, expert contributions, workshops and conferences.

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