A wind tunnel tested control system for a morphing wing actuation mechanism

Abstract

The technique of morphing takes its origin from the bird flight and allows an airplane to change its original configuration during flight depending on the flight conditions. The main objective of the morphing is to improve the mission performance in order to optimize and control the fuel consumption efficiency. The experimental results of a morphing wing concept are presented on a part of the upper surface of the wing which is flexible. The wing was equipped with an aileron which was considered as a separated wing's entity. The objective was to reduce the drag by delaying or by moving the transition point towards the trailing edge. Another project objective was to compare the aerodynamics effects of the rigid aileron with the aerodynamic effects of the morphing aileron. The shape of the wing upper surface was modified by a set of four miniature electrical actuators inserted directly inside the wing. The positions of the actuators were controlled by four different controllers. These controllers have been designed based on the actuators simulation models. Three sets of wind tunnel tests have been performed with the manufactured demonstrator. Experimental resultsrevealed a promising controller behavior. The visualization of the flow over the wing upper surface was done with the infrared measurement technique. Using the same technique, the transition region location was estimated and compared with transition location determined by the pressure sensors array installed in the wing upper surface. Nomenclature M = Mach number α = Angle of attack β = Deflection angle CRIAQ = Consortium for Research and Innovation in Aerospace in Quebec LVDT = Linear Variable Differential Transducer

A new hybrid control methodology for a morphing aircraft wing-tip actuation mechanism

“…The optimisation procedure was applied for several flow conditions obtained by combining different Mach numbers ( M ), angles of attack () and aileron deflection angles (). In this way, the parameters that established the control conditions for the actuators used to morph the flexible skin were the speed, the Reynolds number, the angle-of-attack and the aileron deflection angle (35, 36) .…”

“…Therefore, the genetic optimisation of the wing aerofoil provided the vertical displacements of the four morphing actuators in each optimised flow case (d Y , d Y , d Y , d Y ), generating in this way a database with the needed actuators displacements for different flight conditions. These stored displacements were further used as desired values (reference displacements) for the control system of the morphing wing (35, 36) .…”

“…A flexible skin made of composite fibre materials (Fig. 1 (35–37) ) was mounted on the upper surface of the wing. Spars, ribs, stringers and an aileron are integral parts of the wing model.…”

“…Contrary to the ATR-42 project, there was no actuation mechanism used between the actuators and the flexible skin; the four miniature electromechanical actuators that were used were placed directly at the actuation points on two actuation lines located chord wise at 32% and 48% (Fig. 2 (35, 37) ).…”