Analysis and experimental validation of morphing UAV wings

Abstract

The development of new technologies -such as rapid prototyping -and the use of materials with improved properties -such as highly resistant extruded polystyrene foam which can be easily and precisely shaped, while conserving its mechanical properties -allow researchers to improve design concepts. This paper details the development of a new set of morphing wings for a 15kg maximum take-off weight Unmanned Aerial Vehicle (UAV) from concept design, to flight tests, including modelling, design optimisation, construction and wind tunnel tests. A set of comparator equivalent conventional wings have been used throughout in order to be able to judge any benefits stemming from the adoption of morphing technology. The paper shows that the morphing wings provide a controllable aircraft while reducing drag by a factor of 40% compared to the comparator wings with conventional ailerons in a deflected position. IntroductionMorphing wings have been studied since the earliest days of heavier than air aviation, no doubt based on the commonplace observation that all birds continuously change the shapes of their wings during flight. The original Wright Flyer used "wing warping" for roll control -a fundamental form of wing morphing. There are many and varied ways that the wings of an aircraft can be altered in shape: the planform can be altered in size or span or sweep, section shapes can be altered, either to change lift magnitude and distribution or to gain vehicle control in pitch, roll, yaw, etc., wings can be twisted to alter effective angles of attack. Aeroelastic effects can be deliberately used to make geometry changes -so called aeroelastic tailoring. If allowance is made for the activation and deployment of conventional control surfaces, almost all aircraft lifting surfaces change shape in some way or other. One of the key recent drivers in morphing wing technologies has been the adoption of composite materials such as carbon fibre reinforced plastics. These have allowed for considerable tailoring of stiffness properties throughout the geometry of the wings so as to allow close control of the shape changes being achieved. In the wings developed here a careful matching of fibre and foam structural elements is used to govern the shapes taken up by the wing as it morphs.

Comparative Aerodynamic Performance Analysis of Camber Morphing and Conventional Airfoils

“…Researchers have developed camber morphing mechanisms using smart materials [16][17][18], corrugated structures [19], multi-unit rib structures [20], vertically slitted rib structures [21], truss elements and runners [22], pressure-actuated cellular structures [23,24], bio-inspired FishBAC structures [25], monolithic compliant mechanisms [26], or combined form [27] to introduce and validate their effectively working models and design implementation. Some morphing wing design implementations were even validated with an effectively flown test model [27][28][29][30][31]. Probably one of the most similar works done by [32] took the CFD study of morphing wings and compared them with an analytical solution to validate the effectiveness of the suggested numerical models and approaches.…”

Status and Challenges on Design and Implementation of Camber Morphing Mechanisms

“…Chanzy and Keane [13] modelled a compliant wing concept to achieve greatest roll control-featuring a wing cover design, as shown in Figure 6, where an open-slot trailing edge with ribs attached to the spar but detached at the trailing-edge, allowing the upper and lower surfaces to slide over each other. A series of slotted mechanisms in the trailing edge with one being linked to an actuator mechanism controls morphing.…”

Optimization of a Fluidic Vortex Generator’s Control in a Transonic Channel Flow

“…Since the phenomena linked to the interactions between a jet and a crossflow and between a vortex and a shock wave are really nonlinear, an algorithm based on the kriging model is chosen. This method has been widely used in various optimization processes, such as porous media behaviors [35], aerodynamic design [36], and fluid-structure interaction [37]. It has the advantage of not assuming the smoothness of the function.…”