Morphing Airfoil Shape Change Optimization With Minimum Actuator Energy As An Objective

Abstract

Morphing aircraft are multi-role aircraft that use innovative actuators, effectors, and mechanisms to change their state to perform select missions with substantially improved system performance. State change in this study means a change in the cross-sectional shape of the wing itself, not chord extension or span extension. Integrating actuators and mechanisms into an effective, light weight structural topology that generates lift and sustains the air loads generated by the wing is central to the success of morphing, shape changing wings and airfoils. The objective of this study is to explore a process to link analytical models and optimization tools with design methods to create energy efficient, lightweight wing/structure/actuator combinations for morphing aircraft wings. In this case, the energy required to change from one wing or airfoil shape to another is used as the performance index for optimization while the aerodynamic performance such as lift or drag is constrained. Three different, but related, topics are considered: energy required to operate articulated trailing edge flaps and slats attached to flexible 2D airfoils; optimal, minimum energy, articulated control deflections on wings to generate lift; and, deformable airfoils with cross-sectional shape changes requiring strain energy changes to move from one lift coefficient to another. Results indicate that a formal optimization scheme using minimum actuator energy as an objective and internal structural topology features as design variables can identify the best actuators and their most effective locations so that minimal energy is required to operate a morphing wing. BackgroundA morphing aircraft is a multi-role aircraft that, through the use of morphing technologies such as innovative actuators, effectors or mechanisms, changes its state substantially to complete all roles -with superior system performance.1 For instance, for a hunter-killer aircraft, role A is long-duration loiter while role B is high-speed dash and role C is some form of energy deposition to neutralize the target. Morphing aircraft are a major part of a system that requires technology integration to manipulate geometric, mechanical electromagnetic or other mission critical features -on the ground or in-flight -to match vehicle performance to a well-defined environment and mission objective.

Fluidic flexible matrix composites for autonomous structural tailoring

“…As can be seen, the data points from this limited study occupy almost the entire lower-left triangular area on the plot, indicating an extraordinarily wide range of possible properties attainable with F 2 MC technology. Several existing variable modulus materials, such as shape memory alloy (SMA) [8,9], shape memory polymer (SMP) [10,11], piezoelectric ceramic (PZT) [12], piezoelectric single crystal (PZN-PT) [13], magnetostrictive material using Terfenol-D [14], electrochemo-mechanical conducting polymer [15], ionic gel [12], magneto-rheological (MR) elastomer [16,17], dielectric polymers using polyvinylidene fluoride (PVDF) [12], etc. are also plotted in Fig.…”

Actuator-Work Concepts Applied to Unconventional Aerodynamic Control Devices

“…For a requested change in wing shape, the actuators on the wing must provide the work required to deform the wing while being acted on by the aerodynamic forces. Determining the change in wing shape that requires the minimum actuator work allows the morphing device to operate efficiently and with minimum actuator weight 3,4,5,6,7,8 . This paper presents a theoretical study of the relationship between the change in camberline shape of a twodimensional thin airfoil and the resistance of the aerodynamic forces to this change.…”

A Model to Compare the Flight Control Energy Requirements of Morphing and Conventionally Actuated Wings

“…Other works 4,5,6 have investigated the energy relations of morphing wings but have not presented a general method that is comprehensive enough to proceed with an in-depth analysis. The design of an adaptive camberline function facilitates the use of the VLM energy method and beam theory to derive general energy relations for the vehicle and perform a direct comparison with a conventional aircraft.…”