Aerospace and Electronic Systems Magazine October 2017 - 14

Feature Article:

DOI. No. 10.1109/MAES.2017.160133

Measurement of Wing Deflections in Flexible Aircraft
Using the SansEC Smart Sensor
Alok Menon, Melvin Rafi, Georg Schirmer, Teresa Tran, Jonathan Whitford, Nita
Yodo, Yulia Kostogorova-Beller, James Steck, Animesh Chakravarthy, Suresh
Keshavanarayana, Wichita State University, Wichita, KS, USA

INTRODUCTION
Morphing aircraft are those that have the ability to actively change
their shape in flight. There are several benefits of such shape
change. For instance, since the optimal shape of an aircraft varies from one mission to another, the morphing concept enables a
single aircraft to perform multiple missions during a single flight
by executing its shape change feature. The morphing concept also
enables an aircraft to achieve performance benefits, such as reduced drag during cruise and increased lift during take-off. The
morphing concept is currently being investigated for both largescale passenger sized aircraft [1], as well as small-scale robotic
micro air vehicles [2].
The morphing concept is typically most effective when the
airframe is flexible, since this results in reduced actuation forces
required to bring about the shape change. It then becomes important to be able to measure this shape change actively in flight, and
subsequently feed this information back to a flight control system.
Several methods are being explored to measure wing movement-
these include laser displacement sensors [3], biomimetic optical
sensors [4], and fiber Bragg grating sensors embedded in the wing
[5]. Other technologies, based on transduction of external stimuli
into electrical signals, include e-skins, flexible films with embedded piezoresistive microsensors, arrays of micro electro-mechanical systems, capacitive and piezoelectric microsensor components,
as well as electro-optical thin-films and flow sensing elements [6]-
[8]. Micro- and nano-material technologies are also being actively
pursued, with research focused on incorporating carbon nanotubes

Authors' addresses: A. Menon, M. Rafi, G. Schirmer, T. Tran,
J. Steck, A. Chakravarthy, S. Keshavanarayana, Department of
Aerospace Engineering, Wichita State University, Wichita, KS
67260, USA. J. Whitford, Department of Physics, Wichita State
University, Wichita, KS 67260, USA. N. Yodo, Department of
Industrial and Manufacturing Engineering, Wichita State University, Wichita, KS 67260. Y. Kostogorova-Beller, National Institute of Aviation Research, Wichita State University, Wichita,
KS 67260, E-mail: (animesh.chakravarthy@wichita.edu).
Manuscript received June 8, 2016, revised October 5, 2016, December 21, 2016, and ready for publication February 19, 2017.
Review handled by M. Jah.
0885/8985/17/$26.00 © 2017 IEEE
14

into flexible matrices to achieve a nanocomposite-based distributed sensor network.
This article explores a novel innovative approach for strain
sensing that is based on the electromagnetic SansEC [9] sensing
concept. The SansEC is extremely light in weight, requires no electrical connections (being driven by electromagnetics), and works
even when partially damaged. Furthermore, since it is a flexible
sensor, it can be directly adhered to the surface of the flexible wing.
The SansEC is a relatively new technology. Developed by the
National Aeronautics and Space Administration (NASA), SansEC
is an open-circuit, resonant sensor made of copper foil cut in a
spiral pattern. The sensor requires no electrical connections (hence
the name "SansEC", which translates to "without electrical connections"), and is capable of measuring multiple physical phenomena at the same time. There have been other recent investigations
into the use of SansEC in several applications, such as detection of
damage in composite aircraft structures caused by lightning strikes
[10], monitoring of tire health in vehicles [11], and for other electrical, mechanical, thermal, and chemical phenomena [12]. The
objective of this article is to investigate the use of SansEC for measuring the wing shape of a morphing aircraft. Towards this end, a
SansEC sensor array is applied to the external surface of the wings
of a flexible aircraft to form a smart skin layer that possesses integrated sensing and data transmitting capabilities. Each individual
sensor in the array is sans (without) electrical connections and can
serve as an element of a smart skin for measuring wing shape in
morphing aircraft applications, as is schematically represented in
Figure 1.

Figure 1.

SansEC Sensor smart skin for morphing wing aircraft.

IEEE A&E SYSTEMS MAGAZINE

OCTOBER 2017

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