ℒ₁ Adaptive Flutter Suppression Control Strategy for Highly Flexible Structure

Abstract

The aim of this work is to apply an innovative adaptive ℒ 1 techniques to control flutter phenomena affecting highly flexible wings and to evaluate the efficiency of this control algorithm and architecture by performing the following tasks: i) adaptation and analysis of an existing simplified nonlinear plunging/pitching 2D aeroelastic model accounting for structural nonlinearities and a quasi-steady aerodynamics capable of describing flutter and post-flutter limit cycle oscillations, ii) implement the ℒ 1 adaptive control on the developed aeroelastic system to perform initial control testing and evaluate the sensitivity to system parameters, and iii) perform model validation and calibration by comparing the performance of the proposed control strategy with an adaptive back-stepping algorithm. The effectiveness and robustness of the ℒ 1 adaptive control in flutter and post-flutter suppression is demonstrated. Results and discussion will follow with pertinent conclusions and future outlooks. CITATION: Cassaro, M., Battipede, M., Marzocca, P., Cestino, E. et al., "ℒ Adaptive Flutter Suppression Control Strategy for Highly Flexible Structure," SAE Int.

Aeroelastic System Control by a Multiple Spoiler Actuation and MRAC Scheme

“…The latter represents the reference benchmark for results evaluation. The control objective, as literature suggests [4][5][6][7][8][9][10][11][12][13][14], is to regulate to zero the pitch angle , while adaptively compensating for uncertainties and nonlinearities in the model parameters. It has been already proven, that controlling is sufficient to regulate simultaneously also the plunge displacement ℎ.…”

“…In [11] the authors tested and validated several adaptive control architectures on similar 2D aeroelastic model. The control systems developed, including the most recent neural network [12], adaptive back-stepping [13] and L_1 adaptive controller [14], have been applied to wing models, in simulation or experimental setup, with either a single trailing edge control surface or a combination of leading and trailing edge control surfaces. Some issues related to the latter solutions can be highlighted; these are trailing edge flap saturation, being the flap displacement usually constrained between +/-10 degrees, and leading edge slat actuation system complexity.…”

Comparison of Adaptive Control Architectures for Flutter Suppression

“…Such continuous nonlinear model for stiffness results from a thin wing or propeller subjected to large torsional amplitudes [5]. Similar models [3,11,15,16] have been examined and provide a basis for comparison. The aerodynamically unbalanced control surface deflection β is measured from the axis created by the airfoil at the control flap hinge and is positive for flap down.…”

“…The evaluation of the nonlinear flutter instability of slender wings represents a critical condition to test and validate control algorithm, [1][2][3][4] are case in point. On a benchmark 2D aeroelastic model several linear and nonlinear active controllers [5,6,7] as well as various adaptive control schemes [2,3,7,8] analyzed. The standard direct MRAC solution [9] serves as threshold to assess whether or not the 1 Ph.D Candidate, Department of Mechanical and Aerospace Engineering, C.so Duca degli Abruzzi 24.…”

“…Visiting Scholar in the Mechanical and Aeronautical Engineering Department at Clarkson University 2 Associate Professor, Department of Mechanical and Aerospace Engineering, C.so Duca degli Abruzzi 24. 3 Professor, Department of Mechanical and Aeronautical Engineering, 8 Clarkson Avenue. 4 Associate Professor, Department of EECS and NanoScience Technology Center, 12424 Research Parkway Suite 400. more complex algorithms are an effective improvement to it.…”