Suppression of the Aeroelastic/Aeroservoelastic Interaction Using Adaptive Feedback Control Instead of Notching Filters

Abstract

This paper investigates the possibility that an adaptive feedback controller can be designed and implemented for the suppression of aircraft's structural vibration in the presence of any aeroelastic/aeroservoelastic interaction, instead of using the non-adaptive notching filters. Currently aircraft with non-adaptive control laws usually include roll-off or notch filters to avoid AE/ASE interactions. However, if changes in the aircraft configuration are significant, the frequencies of the flexible modes of the aircraft may be shifted and the notch filters could become totally ineffective. With the proposed adaptive feedback control technology, the flexible dynamics can be consistently estimated via system identification algorithms and its undesirable effects are suppressed through a robust feedback control law, while the whole systems stability is being maintained. The proposed feedback control technique is demonstrated with a 6-DOF nonlinear F/A-18 AAW model for the suppression of the aeroelastic/aeroservoelastic interaction.

A Continuous Robust Control Strategy for the Active Aeroelastic Vibration Suppression of Supersonic Lifting Surfaces

“…The boundedness of r implies that α, α are bounded by virtue of the definitions of (18) and (19). Since the system is minimum phase and relative degree one, the boundedness of the output guarantees that any first order stable filtering of the input will remain bounded.…”

“…A plethora of techniques is available for dealing with the effect of non-linear structural stiffness in the context of subsonic flow; linear control theory, feedback linearizing techniques, adaptive, and robust control techniques have been employed to account for these nonlinearities, e.g., [8]- [19]. Recently, neural-network-based (i.e., model-free) control approaches have been proposed in [20] and [21] to stabilize a nonlinear aeroelastic wing section.…”

“…Motivated by our previous work in [19][21] and [23]- [25], a novel neural network (NN) based robust controller has been designed to asymptotically stabilize a supersonic aeroelastic system with unstructured nonlinear uncertainties. The nonlinearity of the model depends on the plunging distance and pitching angle.…”

Modal Filtering for Control of Flexible Aircraft

“…Some researchers are seeking AFS solutions as an alternative to passive methods. 5 Maryland) in 2010 on the SensorCraft vehicle showed that a 25% total weight savings could be achieved by incorporating AFS into the controller. 7 Increasing flexibility in the structure of the wing may come with other consequences.…”

Flight Dynamics of a Micro Air Vehicle with Aeroservoelastic Interactions across a Range of Wing Stiffness

“…[10][11][12][13][14][15] The frequency of the modes are predicted either through computational methods or through experimental tests. A filter is then designed that reduces any energy from the controller commands within the spectrum of the notch.…”