Parts in a framework
Somewhat simplified, you can say that aircraft have traditionally been designed on a piece-by-piece basis – the undercarriage, the wings, the radar, and so on, each component designed independently of the others. Multidisciplinary design optimization (MDO) regards the complete vehicle as an entirety, and right from the start the design of each component takes the larger, unified system into consideration.
Athanasios Papageorgiou with his thesis.
MDO involves computer models for each individual part being run together in a large, automated framework. This demonstrates how the different parts influence each other, and how the final result for the complete aircraft depends on the input values.
In his doctoral thesis, Design Optimization of Unmanned Aerial Vehicles: A System of Systems Approach, Athanasios Papageorgiou investigates how design optimisation can be improved for unmanned aerial vehicles (drones). The research has been carried out in collaboration with Saab, and has led to new models principally for sensors, communication systems and electrical systems.
Design with compromises
The thesis also discusses models for what is known as “stealth technology” and how it influences other properties of the drone.
“Design always involves compromise. If you give priority to, for example, aerodynamics, you will use another design than you would to give priority to strength or propulsion”, says Athanasios Papageorgiou.
Illustration of how UAV:s can be used together with helicopters and boats.
“My job is not to determine which design is best. What I do, in contrast, is to develop tools for the people who take such decisions. They can base their decisions on a better foundation, quite simply.”
In the second part of the thesis, Athanasios Papageorgiou takes an additional step and investigates what are known as “systems of systems” (SoS) for drones. In this case, the individual vehicle is considered not only as an entirety, but also as a component in a larger system with other independent units.
A concrete example is when drones are used together with helicopters and boats for search and rescue operations. The components complement each other and create an effective unity – drones are effective for discovering people in need but are not very good at providing assistance. Boats and helicopters are better for this.
The SoS paradigm also takes into consideration that the area of application of unmanned aerial vehicles is not static, but can change with time.
- “Both MDO and SoS are already used in the aerospace industry. They can each be used independently, or they can be combined to obtain more knowledge of complex products”, says Athanasios Papageorgiou.
The thesis work also led to a completely unexpected result. Simulations showed that the search for missing people can be made more efficient when drones are used.
“Indeed – we have seen how three drones can improve the search within a certain area. This is a positive effect that we did not expect”, says Athanasios Papageorgiou.
The thesis is a compilation thesis in which seven articles are included. It is based on two theoretical literature studies and four practical case studies.
What is most importan? Different prioritizations affects the design of an aircraft.