A Model to Compare the Flight Control Energy Requirements of Morphing and Conventionally Actuated Wings (original) (raw)
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Design and Trajectory Optimization of a Morphing Wing Aircraft
2018 AIAA/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference, 2018
Adding morphing wing technology to aircraft could drastically reduce the fuel burn required to complete a certain mission. This gain comes from the wing being able to adapt to become optimal for the desired flight condition. For maximal benefit, we must design the wing, morphing inputs, and mission trajectory simultaneously. In this work, we perform gradient-based aerostructural optimization for a morphing Common Research Model wing while optimizing its nominal design, morphing twist across its mission, and its altitude profile. Using a morphing optimization approach that simultaneously optimizes the mission and design, we find a 0.2 to 0.7% fuel burn decrease compared to a non-morphing design optimization, where the benefit increases with range. We also compare the fully coupled optimization approach with a surrogate-based approach to determine if we can simplify the optimization problem while still arriving at the optimal result. We find that the surrogate-based approach finds an optimum within 1.5% of the optimum obtained from the fully coupled approach and that the difference is smaller for smaller ranges.
Energy-based aeroelastic analysis of a morphing wing
Modeling, Signal Processing, and Control for Smart Structures 2007, 2007
Aircraft are often confronted with distinct circumstances during different parts of their mission. Ideally the aircraft should fly optimally in terms of aerodynamic performance and other criteria in each one of these mission requirements. This requires in principle as many different aircraft configurations as there are flight conditions, so therefore a morphing aircraft would be the ideal solution. A morphing aircraft is a flying vehicle that i) changes its state substantially, ii) provides superior system capability and iii) uses a design that integrates innovative technologies. It is important for such aircraft that the gains due to the adaptability to the flight condition are not nullified by the energy consumption to carry out the morphing manoeuvre. Therefore an aeroelastic numerical tool that takes into account the morphing energy is needed to analyse the net gain of the morphing. The code couples three-dimensional beam finite elements model in a co-rotational framework to a lifting-line aerodynamic code. The morphing energy is calculated by summing actuation moments, applied at the beam nodes, multiplied by the required angular rotations of the beam elements. The code is validated with NASTRAN Aeroelasticity Module and found to be in agreement. Finally the applicability of the code is tested for a sweep morphing manoeuvre and it has been demonstrated that sweep morphing can improve the aerodynamic performance of an aircraft and that the inclusion of aeroelastic effects is important.
Journal of Intelligent Material Systems and Structures, 2011
An aero-structural design and analysis study of a telescopic wing with a conformal camber morphing capability is presented. An aerodynamic analysis of a telescoping wing, first with a high speed airfoil followed by an analysis with a low speed airfoil is performed. The data obtained from these analyses is used to determine the optimum polar curves for drag reduction at different speeds. This information in turn provided the background for devising an optimal morphing strategy for drag reduction assuming that the telescoping wing airfoil has the capability to step morph between the high and low speed airfoils.
Aerodynamic Optimization of a Morphing Airfoil Using Energy as an Objective
AIAA Journal, 2007
Recent advances in materials science and actuation technologies have led to interest in morphing aircraft. The research discussed in this paper focuses upon the shape design of morphing airfoil sections. In the efforts herein, the relative strain energy needed to change from one airfoil shape to another is presented as an additional design objective along with a drag design objective, while constraints are enforced on lift. Solving the resulting multiobjective problem generates a range of morphing airfoil designs that represent the best tradeoffs between aerodynamic performance and morphing energy requirements. From the multiobjective solutions, a designer can select a set of airfoil shapes with a low relative strain energy that requires a small actuation cost and with improved aerodynamic performance at the design conditions.
Optimization of a Morphing Wing Based on Coupled Aerodynamic and Structural Constraints
AIAA Journal, 2009
This paper presents the work done in designing a morphing wing concept for a small experimental unmanned aerial vehicle (UAV), in order to improve the vehicle's performance over its intended speed range. The wing is designed with a multidisciplinary design optimization tool where an aerodynamic shape optimization code coupled with a structural morphing model is used to obtain a set of optimal wing shapes for minimum drag at different flight speeds. The optimization procedure is described as well as the structural model. The aerodynamic shape optimization code, which uses a viscous 2-dimensional panel method formulation coupled with a non-linear lifting-line algorithm and a sequential quadratic programming (SQP) optimization algorithm, is suitable for preliminary wing design optimization tasks. The morphing concept, based on changes in wing planform shape and wing section shape achieved by extending spars and telescopic ribs, is explained in detail. Comparisons between optimized fixed wing performance, optimal morphing wing performance and the performance of the wing obtained from the coupled aerodynamic-structural solution are presented. Estimates for the performance enhancements achieved by the UAV when fitted with this new morphing wing are also presented. Some conclusions on this concept are addressed with comments on the benefits and drawbacks of the morphing mechanism design.
Airfoil optimization for morphing aircraft
2005
Continuous variation of the aircraft wing shape to improve aerodynamic performance over a wide range of flight conditions is one of the objectives of morphing aircraft design efforts. This is being pursued because of the development of new materials and actuation systems that might allow this shape change. The main purpose of this research is to establish appropriate problem formulations and optimization strategies to design an airfoil for morphing aircraft that include the energy required for shape change. A morphing aircraft can deform its wing shape, so the aircraft wing has different optimum shapes as the flight condition changes. The actuation energy needed for moving the airfoil surface is modeled and used as another design objective. Several multi-objective approaches are applied to a low-speed, incompressible flow problem and to a problem involving low-speed and transonic flow. The resulting solutions provide the best tradeoff between low drag, high energy and higher drag, l...
A Generic Morphing Wing Analysis and Design Framework
Journal of Intelligent Material Systems and Structures, 2011
A generic framework for morphing wing aeroelastic analysis and design is presented. The wing is discretised into an arbitrary number of wing segments. Two types of actuation mechanisms are identified: inter-rib mechanisms operating across a wing segment and intra-rib mechanisms acting between two adjacent wing segments. Virtually, any shape can be obtained by distributing four morphing modes over the entire morphing wing. Three are an intra-rib mechanism and one is an inter-rib mechanism. The intra-rib modes are wing shear, twist and extension, and the inter-rib mode is wing folding. The wing is modeled using a close coupling between a non-linear beam formulation and Weissinger aerodynamics. The framework is intended to aid quick preliminary design of morphing wings to trade-off contradictory requirements in a flight mission. The morphing wing can be optimized for discrete points in the flight mission, and for the entire flight mission. The framework can be used to predict aerodynam...
Design of a Morphing Wing : Modeling and Experiments
AIAA Atmospheric Flight Mechanics Conference and Exhibit, 2007
This paper details the design and modeling of a novel morphing wing developed at Texas A & M University. Twistable sections with an elastomeric skin characterize the wing as a distinct actuator in aerospace vehicles. Aerodynamic models of the wing were developed using Prandtl's Lifting Line Theory. 1 These models were validated using wind tunnel tests conducted at the low speed wind tunnel at Texas A& M University. It was found that the operating envelope of the angle of attack of the wing was enhanced by the twistable sections.