Airborne Aero-Optics Laboratory - Transonic (AAOL-T)

Jumper, Eric J.

doi:10.2514/6.2015-0675

Cited by 21 publications

(2 citation statements)

References 43 publications

(81 reference statements)

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“…A large body of work has been performed to characterize aero-optical effects on the Airborne Aero-Optics Laboratory 8 (AAOL), which is shown in Figure 3, and its transonic successor AAOL-T 9 . AAOL consists of a pointing and a tracking aircraft.…”

Section: Introductionmentioning

confidence: 99%

A Robust Modification of a Predictive Adaptive-Optic Control Method for Aero-Optics

Burns

Jumper

Gordeyev

2016

47th AIAA Plasmadynamics and Lasers Conference

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A modification of a previous predictive adaptive-optic controller is presented in this paper. Conventional adaptive-optic controllers suffer from bandwidth limitations caused by latency in their control loops. This latency severely limits their capabilities in aero-optic applications that cannot be overcome with conventional feedback techniques. Our method uses prior knowledge of flow behavior to predict future behavior, and thus overcome deadtime. We have modified our previous neural network controller to use a linearized predictor, which we demonstrate to be more accurate, more robust to noise and flow disturbances, and less computationally expensive. Our previous neural network method showed disturbance rejection in the range of 35-55% in simulation over our test conditions in the most optically-active regions, while the improved method shows disturbance rejection between 45-75% over the same range. Additionally, we demonstrate that the predictive control method is stable, even in the presence of latency uncertainty.

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Section: Introductionmentioning

confidence: 99%

A Robust Modification of a Predictive Adaptive-Optic Control Method for Aero-Optics

Burns

Jumper

Gordeyev

2016

47th AIAA Plasmadynamics and Lasers Conference

Self Cite

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“…The optical path difference (OPD) will be highly affected, particularly as the beam is transmitted through the wake and shock region, according to experimental data provided by the Airborne Aero-Optics Laboratory (Jumper et al 2012;De Lucca et al 2013;Jumper et al 2013;Porter et al 2013;Jumper et al 2015Jumper et al , 2018. The distortion of the wavefront produced in the relatively turbulent zone, which spans the turret diameter, may eventually affect the beam, causing phenomena such as defocus, jitter, pointing errors, and changes in the distribution of light intensity (Mani et al 2009;Wang et al 2012).…”

Section: Introductionmentioning

confidence: 99%

Numerical Investigation of the Influences of the Features of Transonic Flow over a Hemispherical Turret on Beam Wavefront Distortions

2023

JAFM

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Complex features of transonic flow over a turret make it challenging to use passive flow control to reduce aero-optical effects. In this study, the influence of different flow features on wavefront distortions is numerically investigated through improved delayed detached eddy simulation coupled with a modified sub-grid scale. The proper orthogonal decomposition (POD) method is used to study the spatiotemporal characteristics of the flow features. The flow field changes in the wake along with the motion of the shock. Two features, namely, lateral shift (dominant in modes 1 and 2) and wall-normal fluctuation (dominant in modes 3 and 4) of the wake, are the most dominant in the flow field. All beams share the common feature of transmitting the flow field, in which a large component of optical path difference (OPD) appears at St=0.35, indicating the high impact of wall-normal fluctuation on the distortion of the wavefront. After the different POD modes, which contain 30% of the mode energy, are removed, all beams transmitted through different reconstructed fields show very different features for OPD. The flow features that do not exhibit higher-order modes from modes 21 to 92 affect the OPD slightly, as the OPD components in the low-St region are almost unchanged. With the removal of modes from 3 to 32, wavefront distortions are considerably reduced, particularly at St=0.35. The wavefront distortions are most reduced after the lower order modes from 1 to 20 are removed, as the components of OPD in the low-St region are dramatically reduced. The significant relations between OPD and the flow features reveal that controlling the dominant flow features has significant potential for reducing aero-optical effects.

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Introduction

2021

Introduction to Flight Testing

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Airborne Aero-Optics Laboratory - Transonic (AAOL-T)

Cited by 21 publications

References 43 publications

A Robust Modification of a Predictive Adaptive-Optic Control Method for Aero-Optics

A Robust Modification of a Predictive Adaptive-Optic Control Method for Aero-Optics

Numerical Investigation of the Influences of the Features of Transonic Flow over a Hemispherical Turret on Beam Wavefront Distortions

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