Multi-Agent Systems for Formation and Coupling Control of Compound Aircraft

• Applicants: Professorin Dr. Steffi Knorn; Professor Dr.-Ing. Alexander Köthe
• Subject Area: Fluid Mechanics ; Automation, Mechatronics, Control Systems, Intelligent Technical Systems, Robotics
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 554941770

To use unmanned aerial vehicles as high-altitude platforms complementary to satellites, they must operate at high altitudes for long periods. Since solar energy is the only available energy source and is limited, these aircraft must have low aerodynamic drag, which is achieved through high aspect ratios at low airspeeds. Although they operate in the stratosphere with fewer atmospheric disturbances, they must pass through the turbulent troposphere, requiring a stiff structure that increases structural weight and energy consumption, hindering their use as high-altitude platforms. A solution to this limitation is the concept of the compound aircraft. This consists of several individual aircraft with low aspect ratios that fly separately into the stratosphere and then form a formation. The mechanical connections between the aircraft prevent the transfer of structural loads. The current state of the art includes the flight dynamic modeling and central control of the compound; however, the coupling process and its associated control are still unexplored. This research project aims, in the first step, to develop a mathematical model for the coupling process of a compound consisting of n individual aircraft. First, an aerodynamic model will be created to depict the interactions between a compound of m aircraft and an aircraft to be coupled. The aerodynamic model, along with other known kinetic and kinematic models, will be described in a Multi-Agent System (MAS) to establish a foundational framework. This framework enables the transition from a central to a decentralized control approach. Each individual aircraft will have its own controller, exchanging information with its neighbor to avoid a single point of failure and ensure the safe, scalable operation of the compound aircraft. The concept of decentralized control will first be applied to the compound and compared with the central control approach. It will then be transferred to the coupling process, closing a gap in the state of the art and enabling the use of compound aircraft as high-altitude platforms. A trajectory for an individual aircraft will be defined to couple as energy-efficiently as possible with a compound or another individual aircraft. The trajectory will be executed through a combination of feedforward and feedback control. To validate the results, a highly accurate simulation environment will be created in which the control of the compound flight and the coupling process will be tested. Nonlinear simulation results will allow conclusions to be drawn about the methods, models, and results developed, further improving the research findings and confirming the developed modeling approaches and control strategies.

• DFG Programme: Research Grants
• International Connection: Netherlands, USA
• Cooperation Partners: Professor Dr. Bart Besselink; Professor Dr. Carlos Cesnik