SZTAKI researchers have been working on the future of aviation for more than a decade. The initial focus of component level fault diagnostics is shifting towards overall aircraft level design tools that lead to environmentally friendlier aircrafts.

As consortium leaders in the European Union, researchers from SZTAKI have participated in several international research projects. Solutions are developed in close cooperation with key players in the European aerospace industry.

Photo: SZTAKI

ADDSAFE

Initially, the researchers developed fault diagnosis algorithms. Later, between 2009 and 2012 as part of the ADDSAFE FP7 project, they participated in a competition in partnership with the leading Universities of Europe and research institutes to solve tasks defined by the aircraft manufacturer Airbus.

In the international competition, the SZTAKI team solved the fault detection problem of actuators mounted on the wings, which are responsible for moving the flight control surfaces. They tied first place with the University of Bordeaux, whose algorithm was later selected for onboard production implementation by Airbus.

As a special feature of the project, the theoretical research results were brought all the way to physical integration into the on-board avionics of the aircraft. The results of the competition were tested and ranked by independent Airbus engineers.

Photo: Fabian Vogl / TUM

FLEXOP

Building on the above mentioned successes, the RECONFIGURE FP7 project was launched, which targeted the autopilot system reconfiguration. The conditions were once again set by Airbus.

In 2015, with the help of the FLEXOP project of the EU Horizon 2020 program, ten significant representatives of the European aerospace industry – led by SZTAKI – formed a consortium with the goal of making aviation more economical.

Other members of the consortium included the German Aerospace Center, several well-known European universities (Bristol, Munich, Delft, Aachen), and major suppliers of the aerospace industry (Austrian FACC and Greek INASCO).

Researchers successfully studied the flexible behavior of aircraft wings and began to establish a control system capable of presenting the theoretical results of the project in an industrial environment. For the first time ever, an aircraft with aeroelastically tailored wings, aimed for load alleviation, flew in a real environment. The carbon fiber composite fiber orientation changes along the wing. The purpose of the flight was to test the passive damping of the load on the wings. This means that weight can be reduced, resulting in up to 7 percent in savings on fuel.

SZTAKI’s research laid the foundations for the models required for control design and the advanced control algorithms based on them. In addition to the theoretical results, on the practical side, SZTAKI designed, built and operated the on-board avionics (electric and electronic flight) system, including in-flight sensors and actuators, and the software and hardware components of the on-board autopilot system to collect data and execute repeatable experiments.

Photo: SZTAKI

FLiPASED

In 2019, an international project called FLiPASED (FLight Phase Adaptive Aero-Servo-Elastic Aircraft Design) was launched in the European Union’s Horizon 2020 framework program to modernize aircraft wings by developing and testing active-controlled wings.

SZTAKI is responsible for organizing the FliPASED . Control theory, aircraft structural and aerodynamic design are jointly developed to coordinate the physical design of the aircraft and the flight control software algorithms in a multidisciplinary environment. The following partners take part in the research: the Technical University of Munich (TUM), the German Aerospace Center (DLR), and the French Aerospace Lab (ONERA).

Aircraft needs the right mix of air resistance and lift to handle changing flight conditions. Aircraft manufacturers aim to reduce air resistance (drag) and thus save fuel. This is achieved by so-called composite wings, which are very slender and elastically deformable.

The wings are built by combining several materials and using fibers for reinforcement. These are known as composite materials. The technology used so far in the wings and engines of modern aircraft has now reached the limit of its efficiency.  More than 50 percent of the weight of the Boeing 787 and Airbus A350 aircraft consists of these composite materials. Commercial airlines spend more than 25 percent of their operating costs on fuel. More efficient fuel use is an important topic from both an environmental and financial perspective.

Until recently, the design process of structures and aerodynamics was only loosely coupled with the design of the control system. The tuning of the aeroelastic behavior in flight tests, such as handling wing flapping, could only be carried out passively by using extra weight and structural stiffeners.

Airplane wings were previously designed to have minimum drag for a single flight configuration. When conditions change, fine tuning of aerodynamic surfaces is required to change the lift to drag ratio. In contrast to the previous solutions, the shape of the actively controlled flexible wings is finely tunable and able to adapt to a wide range of flight conditions. One aim of the airlines is to reach their destination using the straightest and shortest path. Crossing atmospheric turbulence often causes problems both in terms of flight safety and the comfort of passengers. As a result of global warming, more and more turbulence-related meteorological fluctuations are expected in the atmosphere. Turbulence is much more noticeable for passengers on a rigid-wing aircraft.

The methods developed in the project due to the flexibility of the wing in addition to the active elastic control system lead to the reduction of the physical loads on the aircraft and passengers. In the same way, different wing shape settings can be selected for take-off and landing to achieve an enjoyable and efficient flying experience

Based on SZTAKI’s research results so far, the effect of gusts of wind can be reduced by 20 percent with an active wing. Fuel consumption can be improved by 10 percent, thanks to continuously deforming wing shapes along the route that reduces air resistance.

Experts measure more than 500 parameters 200 times a second on the experimental aircraft used for the development, creating significant amounts of data, representing 1.5 GB of raw data per hour.

SZTAKI’s IT laboratory is also involved in the project under the leadership of András Benczúr. Data mining methods will make it possible to fine-tune the optimal wing shape settings of aircrafts as the optimal parameters vary from aircraft to aircraft and as the wing ages.

The goal is to put the research results, scheduled for completion by the end of 2022, into practice within five to ten years. The project’s advisory board includes industry partners from Airbus Operations SAS (the world’s leading passenger aircraft company), Airbus Defense and Space (military and aerospace), and Dassault Aviation (business jets and autonomous drones), as well as Scientific advisors from the University of Michigan.

The results of the project will be presented not only in a simulation, but also on a seven-meter unmanned aerial vehicle built for research purposes.