Small Testbed Development to Study Aeroelastic Effects in Large Solar Powered Airplanes

Student : Pedro Jose Gonzalez Ramirez

Sponsors : Center for Unmanned Aircraft Systems (C-UAS), AeroVironment Inc., Aurora Flight Sciences Corporation and Facebook Inc.


Summary:

The X-HALE testbed is a small remote piloted aircraft designed and built at the University of Michigan to mimic the main aeroelastic characteristics of solar-powered planes. Although is it powered by batteries and fly within 30 meters above the ground, the flying experiment can be used to further investigate this coupled elastic response with free-flight dynamics that is key in solar-powered airplanes. The X-HALE will serve as a low-cost platform to collect aeroelastic data. The airframe is outfitted with multiple control surfaces. As the baseline, pitch and roll are controlled by the horizontal elevons, and yaw is controlled using differential thrust from the motors. Disturbances can be applied with schedule all-movable horizontal ail deflections supplemented by ailerons/spoilerons on the dihedral outer-wing sections. Change in wing shape (shape control) can be achieved via tail elevons and/or dihedral wing spoilerons. Disturbances can excite wing deformation during flight, and the response can be recorded from a series of on-board sensors. Two pairs of stereovision cameras have been integrated with the airframe along with span-wise LED markers to allow for deformation measurement during flight. Redundant control surfaces and effectors will be an integral part of the study, as well as configuration flexibility. Currently, the X-HALE can be easily configured to fly as a 4-m span/3 motors (relatively stiff), a nominal 6-m span/5 motors (very flexible), and an 8-m span/5 motors (highly flexible). The plan for this study is to fly the 6-m configuration that should provide sufficient flexibility at a relatively low risk to enable better understanding of the fundamental physics involved in the very flexible aircraft flying regime.

The objectives of this research are:

  • Conduct ground experiments to characterize the elastic properties of the testbed;
  • Conduct flight experiments to collect airframe deformation and rigid body motion in
    response to control inputs;
  • Conduct data reduction from both ground and flight tests;
  • Create a well-documented database of experimental data collected from flight test to be
    disseminated in the open literature so to support code validation from various research
    groups working on similar problems

 

X-HALE testbed
X-HALE testbed
X-HALE instrumentation
X-HALE instrumentation
Ground Station
Ground Station