Active Control of Wing Flutter Using Piezoactuated Surface

Abstract

A flutter suppression concept is demonstrated by performing wind-tunnel tests in a low subsonic flow regime. The wing model, with a trailing edge control surface, is constructed to have a bending-torsion flutter. The control surface is actuated by a flexure-hinged lead zirconate titanate stack mechanism acting as an aerodynamic effector. The flutter experiments are conducted using a digital controller, implemented in dSPACE DS1104, keeping the wing model at 4 deg angle of attack. The wing response is measured by lead zirconate titanate sensors, which are used to generate the feedback control to vibrate the control surface in antiphase motion with respect to the main surface to introduce active aerodynamic control. It is noticed that both bending and torsion modes are stabilized in closed-loop configurations. The damping trend of the flutter mode shows an expanded flutter envelope that is estimated to be around 20%. The actuators are operated within 1000 V=mm, though their allowable field strength is 1500 V=mm.

Aeroelastic analysis and flutter control of wings and panels: A review

“…Tang et al 253 investigated the active flutter suppression of airfoils under control‐input constraints using an optimal neural‐network control strategy. In a subsonic flow regime, Raja and Upadhya 254 designed a piezoelectric control surface to enhance the flutter velocity of a composite wing model using theoretical and experimental methods. Liu et al 255 used the parametric active aeroelastic control method to suppress aeroelasitc vibrations and expand flutter bounds of a morphing wing, and a comparison between the open‐loop and the closed‐loop flutter bounds of the folding wing over the folding angle range of interest was carried out as shown in Figure 17.…”

Robust Modal Filtering for Control of Flexible Aircraft

“…Recently developed smart sensor & control technology has prompted further work in ASC. Piezoelectrics [144,145,83] have been receiving increasing attention. They are considered to be a collocated control effector.…”

“…In order to reduce the possibility of flutter, the flutter speed must be known so that pilots do not accidentally cross the flutter boundary. For a proper safety margin, the flutter speed must be 1.2 times the diving speed according to FAR 25.629 [83].…”

System identification-based aeroelastic modelling for wing flutter

“…In a conventional approach (Rodden and Johnson, 1994), the flutter calculation is done in the frequency domain, where the unsteady air loads are computed as a function of Mach number and reduced frequencies. However, to accommodate an aeroservoelastic simulation, it is essential to build a time domain-based aeroelastic model (Karadal et al , 2007; Raja and Upadhya, 2007; Pototzky, 2010; Suh et al , 2015), in which the approximation techniques are used for the discrete air loads to be defined in continuous form (Cotoi and Botez, 2002). The required procedure and scheme to understand and build an aeroelastic state space system has been studied using Roger’s rational polynomial approximation (Abel, 1979).…”