High Angle-of-Attack Flight Dynamics of Small UAVs

Johnson, Baron; Lind, Rick

doi:10.2514/6.2009-61

Cited by 23 publications

(7 citation statements)

References 9 publications

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“…This model was then applied to segments of steady high angle-of-attack flight similar to those used in this study to remove the commanded roll rates from the data and extract the uncommanded roll rates. Removal of these small commanded roll rates did not significantly alter the frequency content or magnitude of the measured roll rate [27]. Therefore, it can be assumed that the aileron commands in these runs do not significantly alter the nature of the measured roll rate either, as the test flights were performed nearly identically and the data exhibit similar traits.…”

Section: Wing Rock a Upright Tailmentioning

confidence: 90%

Characterizing Wing Rock with Variations in Size and Configuration of Vertical Tail

Johnson

Lind

2010

Journal of Aircraft

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Flight at high angle-of-attack conditions, which range beyond wing stall, has numerous advantages for mission performance; however, that flight regime is often affected by adverse behaviors. A particularly notable behavior is associated with uncommanded oscillations primarily about the roll axis and is known as wing rock. This paper investigates wing rock for a small, propeller-powered aerobatic unmanned aerial vehicle with a high degree of vertical symmetry flown at high angle-of-attack conditions. Most importantly, the investigation characterizes the nature of wing rock as a function of size and configuration of the vertical tail. The flight data indicate that wing rock is dependent on the configuration but not on the size of the vertical tail: wing rock oscillations are present for upright but not inverted regardless of vertical tail size. Furthermore, a time-frequency analysis indicates that the wing rock is actually a narrowband phenomenon for which the central frequency varies with time.

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Section: Wing Rock a Upright Tailmentioning

confidence: 90%

Characterizing Wing Rock with Variations in Size and Configuration of Vertical Tail

Johnson

Lind

2010

Journal of Aircraft

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“…3 Using a similar motion capture system, researchers at the University of Illinois parameterized a micro, aerobatic aircraft to determine its aerodynamic characteristics, including lift, drag, and moment curves over a wide flight regime. 4 Moving onto outdoor aircraft, researchers at the University of Florida used a small outdoor aerobatic unmanned aircraft to investigate aircraft high angle-of-attack flight dynamics, which included stability issues that related to side slip 5 and wing rock [6][7][8] and later further parameterized the same aircraft in order to design trajectory-following algorithms; 9, 10 this aircraft had all sensors and recording equipment on board. However, performing experiments outdoors does come with the problem of external disturbances, the most significant of which is wind.…”

Section: A Literature Review Of Aerobatic Unmanned Aircraft Used Formentioning

confidence: 99%

Development and Initial Testing of the Aero Testbed: A Large-Scale Unmanned Electric Aerobatic Aircraft for Aerodynamics Research

Dantsker

Johnson

Selig

2013

31st AIAA Applied Aerodynamics Conference

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This paper describes the development of a large 35%-scale unmanned aerobatic platform named the UIUC Aero Testbed, which is primarily intended to perform aerodynamics research in the full flight regime. The giant-scale aircraft with a 105-in (2.7-m) wingspan and weight of 37 lb (17 kg) was constructed from a commercially available radio control model aircraft with extensive modifications and upgrades including a 12-kW electric motor system that provides a thrust-to-weight ratio in excess of 2-to-1. It is equipped with an avionics suite that contains a high-frequency, high-resolution six degree-of-freedom (6-DOF) inertial measurement unit (IMU) that allows the system to collect aircraft state data. This information set can be used to generate high-fidelity aerodynamic data that can be used to validate high angle-of-attack flight-dynamic models. Collaboration in this project also led the Aero Testbed to have the capability to fly fully-and semi-autonomously in order to conduct autonomous flight research. A literature review of aerobatic unmanned aircraft used for research is first presented. Then the background and motivations for developing this platform are discussed. This is followed by a description of the planning and development that was involved. Finally, initial test flight results are presented, which include flight path trajectory plots of several aerobatic maneuvers. Nomenclature AV I= avionics integration ARF = almost ready to fly COT S = commercial off the shelf CG = center of gravity DOF = degree of freedom EEG = electroencephalogram IMU = inertial measurement unit RC = radio control

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“…For a missile control system, Johnson and Lind [8] showed sweeping of the model through many ALPHA/BETA orientations, while the control system automatically trimmed out the three primary moments. It also produced trim maps of normal, side, and axial forces as well as the pitch, yaw, and roll commands required for the trim.…”

Section: Introductionmentioning

confidence: 99%

Improving Aileron Effectiveness Based on Changing the Position of Aileron Connectors

Qiu

Ang

2019

International Journal of Aerospace Engineering

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In this paper, the design concept of the aileron with a fixed connector and a moving connector has been explored due to the improvement of aileron effectiveness. As usual, aileron reversal or the blocking phenomenon of multijoint fixed ailerons is a hard nut to crack. In the present research, in order to improve aileron effectiveness, several examples are studied. The connection position influences the stress, displacement, load distribution, and control effectiveness of the aileron or critical flutter speed. As the joint positions are different, the wing-aileron connection stiffness is also changing. The sample of the beam shows the weight reduction. The plate simulation indicates the decreased deformation and the better load distribution. The aileron trimming demonstrates the improvement of aileron effectiveness. And the flutter speed coupled with the aileron is different. All of these examples indicate the feasibility of this new concept of the aileron design, which means improving aileron effectiveness based on changing the position of aileron connectors. Finally, three different modes for wing-aileron connections are suggested for reference.

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High Angle-of-Attack Flight Dynamics of Small UAVs

Cited by 23 publications

References 9 publications

Characterizing Wing Rock with Variations in Size and Configuration of Vertical Tail

Characterizing Wing Rock with Variations in Size and Configuration of Vertical Tail

Development and Initial Testing of the Aero Testbed: A Large-Scale Unmanned Electric Aerobatic Aircraft for Aerodynamics Research

Improving Aileron Effectiveness Based on Changing the Position of Aileron Connectors

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