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This paper presents a new approach of real-time control of a morphing wing based on a coupled fluid-structure numerical model. The 2D extrados profile of an experimental laminar wing is morphed with the purpose to reduce drag, through extension of the laminar flow over the upper wing surface. As a first step, the active structure has been modeled, manufactured and experimentally tested under variable flow conditions in a subsonic wind tunnel (the Mach number ranges from 0.2 to 0.3 and the angle of attack from −1° to 2°). In this work, a real-time closed-loop control strategy is designed to find the optimum actuator strokes using an experimentally measured lift-to-drag ratio (feedback parameter). An extensive wind-tunnel characterization of the laminar wing prototype has been performed to design the algorithm and to set up the parameters. To calculate the initial strokes of the actuators and thus to accelerate the optimization procedure, a validated ANSYS-XFoil coupled fluid-structure numerical model is used. The robustness and efficiency of the developed real-time control system is tested under two flow conditions. The morphing wing performance obtained is slightly superior or similar to the open loop control approach proving the high performance of the numerical model. The proposed control strategy appears to be well suited to benefit from the complete morphing potential (according to the lift-to-drag ratio) of the wind tunnel prototype although higher feedback resolution is recommended from the numerical simulation algorithms., ASME 2009 Conference on Smart Materials, Adaptive Structures and Intelligent Systems, September 21–23, 2009, Oxnard, California, USA, Series: ASME Proceedings

A morphing wing, composed of flexible extrados, rigid intrados and a Shape Memory Alloys (SMA) actuator group located inside the wing box, is used to adapt an airfoil profile to variable flight conditions. The SMA actuator group developed for the morphing wing prototype consists of three main subsystems: the SMA active element, the transmission system, and the passive bias element. The functional requirements for the actuator group were determined using a coupled fluid-structure model of the flexible extrados. An original design approach was applied to determine the geometry and assembly conditions of the SMA active elements. For validation purposes, the morphing wing powered by SMA actuators was tested in a wind tunnel under subsonic flight conditions (Mach = 0.2 to 0.3 and α = −1 to 2°). The ability of the actuator group to move the flexible extrados up to 8 mm of vertical displacement and to bring it back to the initial profile has been successfully proven for all of the wind tunnel testing conditions. During the repetitive actuation, the force, displacement and temperature of the SMA active elements were measured and the results obtained in the force-displacement-temperature space were used to validate the SMA performances predicted during the design phase.Copyright © 2009 by ASME

An active structure of a morphing wing designed for subsonic cruise flight conditions combines three principal subsystems: (1) flexible extrados, (2) rigid intrados and (3) an actuator group located inside the wing box. A structural model of the flexible extrados built with ANSYS finite element software is coupled with X’Foil fluid dynamics software to evaluate mechanical and aerodynamic performances of the morphing wing in different flight conditions. Using the multicriteria optimization technique, an active structure consisting of the 4-ply laminated composite flexible extrados powered by two individually controlled actuators is selected. Shape memory alloy (SMA) actuators are designed as power elements for the morphing wing. To meet the functional requirements of the application, the geometry of the SMA elements is calculated using the results of the constrained recovery testing of the selected material.Copyright © 2008 by ASME