Flutter Control & LCO

Developments of the capabilities and reliability of aircraft control system hardware and software, combined with the growing flexibility, and hence potential for flutter problems solutions and for related weight reduction of optimized composite airframes, seem to have made the implementation of Active Flutter Suppression (AFS) technology closer than ever before. This makes the experimental study of current state of the art AFS important, especially from the perspectives of uncertainty, reliability, and the safety of flight vehicles in which this technology will be used.

Contributing to AFS technology development, and to flight vehicle active control in general, for many years, the Politecnico di Milan (POLIMI) developed in the mid-2000s a scaled actively controlled aeroservoelastic model of a three-surface passenger airplane and tested it in its large low-speed wind tunnel. Motivated by the need to return to the wind tunnel with an aeroservoelastic model of a configuration that would capture the aeroelastic behavior of current and emerging commercial passenger and cargo flight vehicles that may benefit from AFS, a research program has been launched by the Polytechnic of Milan and the University of Washington - Seattle (UWA) in  in 2018 to focus on the reliability and safety of AFS-dependent flight vehicles using a wind tunnel model that would be representative in complexity and aeroelastic characteristic to real aircraft. During the project ASDL Lab developed a modified version of the X-DIA aeroelastic platform to be used as a dedicated platform to experimentally validate active flutter control technologies. 

In a second phase, the TTails of XDIA model have been modified to embed an innovative mechanical system to implement accurate and small scale freeplay on the control surfaces, i.e. elevator and rudder. A dedicated WT campaign allowed to experimentally investigate LCO phenomena to validate different numerical approaches. 

The project ended in August 2024 with a succesfully wind tunnel test campaign where four different active flutter suppression controllers were tested.

• Berg, J., Morgansen, K.A., Livne, E., Riccobene, L., Fonte, F., Toffol, F., De Gaspari, A., Marchetti, L., Ricci, S., Mantegazza, P., Analytical and Experimental Evaluation of Multivariable Stability Margins in Active Flutter Suppression Wind Tunnel Tests, AIAA Scitech 2021 Forum, AIAA, 2021, ISBN: 9781624106095, p. 1-50, AIAA 2021-1261, Virtual Event, 11-21 Jan. 2021], DOI:10.2514/6.2021-1261

• Ricci, S., Marchetti, L., Riccobene, L., De Gaspari, A., Toffol, F., Fonte, F., Mantegazza, P., Berg, J., Morgansen, K.A., Livne, E., An Active Flutter Suppression (afs) Project: Overview, Results and Lessons Learned, AIAA Scitech 2021 Forum, AIAA, 2021, ISBN: 9781624106095, p. 1-22, AIAA 2021-0908, Virtual Event, 11-21 Jan. 2021, DOI:10.2514/6.2021-0908

• Marchetti, L., De Gaspari, A., Riccobene, L., Toffol, F., Fonte, F., Ricci, S., Mantegazza, P., Livne, E., Hinson, K., Active Flutter Suppression Analysis and Wind Tunnel Studies of an Uncertain Commercial Transport Configuration, , AIAA Scitech 2020 Forum, AIAA, 2020, ISBN: 9781624105951, p. 1-17, AIAA 2020-1677, Orlando, FL, USA, 6-10 Jan. 2020, DOI:10.2514/6.2020-1677

• Fonte, F., De Gaspari, A., Riccobene, L., Toffol, F., Malik, S., Marchetti, L., Ricci, S., Mantegazza, P., Livne, E., Development of a Wind Tunnel Model for Active Flutter Suppression Studies, AIAA Scitech 2019 Forum, AIAA, 2019, ISBN: 9781624105784, p. 1-14, AIAA 2019-2029, San Diego, CA, USA, 7-11 Jan. 2019, DOI:10.2514/6.2019-2029

• Fonte, F., De Gaspari, A., Riccobene, L., Toffol, F., Malik, S., Marchetti, L., Ricci, S., Mantegazza, P., Livne, E., Numerical and Experimental Investigations on Active Flutter Suppression Technologies, Paper presented at: 18th International Forum on Aeroelasticity and Structural Dynamics (IFASD 2019), 2019, p. 1-19, Savannah, GA, USA, 10-13 June 2019.