Liu, ShiqianYang, CongjieZhang, QianWhidborne, James F2024-11-142024-11-142024-10-25Liu S, Yang C, Zhang Q, Whidborne JF (2024) Disturbance observer-based backstepping terminal sliding mode aeroelastic control of airfoils. Aerospace, Volume 11, Issue 11, October 2024, Article number 8822226-4310https://doi.org/10.3390/aerospace11110882https://dspace.lib.cranfield.ac.uk/handle/1826/23169This paper studies aeroelastic control for a two-dimensional airfoil–flap system with unknown gust disturbances and model uncertainties. Open loop limit cycle oscillation (LCO) happens at the post-flutter speed. The structural stiffness and quasi-steady and unsteady aerodynamic loads of the aeroelastic system are represented by nonlinear models. To robustly suppress aeroelastic vibration within a finite time, a backstepping terminal sliding-mode control (BTSMC) is proposed. In addition, a learning rate (LR) is incorporated into the BTSMC to adjust how fast the aeroelastic response converges to zero. In order to overcome the fact that the BTSMC design is dependent on prior knowledge, a nonlinear disturbance observer (DO) is designed to estimate the variable observable disturbances. The closed-loop aeroelastic control system has proven to be globally asymptotically stable and converges within a finite time using Lyapunov theory. Simulation results of an aeroelastic two-dimensional airfoil with both trailing-edge (TE) and leading-edge (LE) control surfaces show that the proposed DO-BTSMC is effective for flutter suppression, even when subjected to gusts and parameter uncertainties.enAttribution 4.0 Internationalhttp://creativecommons.org/licenses/by/4.0/4007 Control Engineering, Mechatronics and Robotics40 Engineering4001 Aerospace Engineering4001 Aerospace engineeringaeroelastic two-dimensional airfoilflutter suppressionbackstepping controlfast nonsingular terminal sliding-mode controlnonlinear disturbance observerArticle2226-43105556128821111