Closed-Loop Control of a Constrained, Resonant-Flapping Micro Air Vehicle

Lindholm, Garrison J.; Cobb, Richard

doi:10.2514/6.2012-4980

Cited by 2 publications

(1 citation statement)

References 10 publications

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“…12,14 The materials used in the fabrication process were carbon fiber, Pyralux, 12.5 μm, 25 μm, and 50 μm Kapton, Mylar, porous and nonporous Teflon, and Airweave SS FR bleeder cloth. The hardware used in the fabrication process include an LPKF Multipress S, LPKF Proto Laser U, and Eden 500V rapid prototype machine.…”

Section: A Construction Of Constant Aspect Ratio Longer Span Ratiomentioning

confidence: 99%

Varying Reynolds Number of Biomimetic Flapping Wing By Changing Air Density and Wing Length

Hope¹,

DeLuca²,

O’Hara³

2016

34th AIAA Applied Aerodynamics Conference

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This research investigated how the nature of a biomimetic Manduca Sexta hawkmoth inspired wing changed as a function of Reynolds number by measuring the forces produced by wings with varying characteristic lengths and tested at varying air densities. A six degree of freedom balance was used to measure forces and moments, while high speed cameras were used to measure the stroke angle of the flapping wing. A GUI was used to manipulate the voltage of the drive signal sent to the piezoelectric actuator which determined the stroke angle, Φ, of the wing. The base line 50 mm wing span was compared against wings manufactured with 55, 60, 65, and 70 mm spans, while maintaining a constant aspect ratio. Tests were conducted in a sealed vacuum chamber at air densities between 0.5% and 100% of atmospheric pressure. Increasing the wing span increased the overall weight of the wing, which reduced the 1st natural frequency; and did not result in an increase in vertical force over the baseline 50 mm wing. However; if the decrease in natural frequency corresponding to the increased wing length was counteracted by increasing the thickness of the joint material in the linkage mechanism, vertical force production did increase over the baseline wing planform. Equipped with the more robust flapping mechanism, the 55 mm wing span produced 96% more vertical force at a 26% higher flapping frequency, while the 70 mm wing span produced 188% more vertical force at a 10% lower natural frequency than the baseline wing. Negligible forces and moments were measured at vacuum conditions, where the wing was demonstrating purely inertial motion, revealing the flight forces measured in atmosphere are wholly limited to its interaction with the surrounding air. Lastly, there was clear correlation between Reynolds number and vertical force production, indicating Reynolds number is a suitable parameter to predict the expected lift production for a specific wing design. Nomenclatureβ = stroke plane angle θ = elevation angle φ = wing position angle α = angle of attack Φ = stroke angle f = flapping frequency R = wing length μ = dynamic viscosity AR = aspect ratio δ = piezo tip displacement T = transmission ratio G = passive rotation joint torsional stiffness Eh = passive rotation joint Young's modulus wh = passive rotation joint width th = passive rotation joint thickness lh = passive rotation joint length V = wingtip velocity R2 = alternate wing length L = characteristic length A = driving amplitude η = stroke bias ωn = natural frequency keq = equivalent stiffness meq = equivalent mass Tref = reference temperature q = dynamic pressure S = planform area

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Section: A Construction Of Constant Aspect Ratio Longer Span Ratiomentioning

confidence: 99%

Varying Reynolds Number of Biomimetic Flapping Wing By Changing Air Density and Wing Length

Hope¹,

DeLuca²,

O’Hara³

2016

34th AIAA Applied Aerodynamics Conference

View full text Add to dashboard Cite

show abstract

Investigation into Reynolds number effects on a biomimetic flapping wing

Hope

DeLuca

O’Hara

2018

International Journal of Micro Air Vehicles

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This research investigated the behavior of a Manduca sexta inspired biomimetic wing as a function of Reynolds number by measuring the aerodynamic forces produced by varying the characteristic wing length and testing at air densities from atmospheric to near vacuum. A six degree of freedom balance was used to measure forces and moments, while high speed cameras were used to measure wing stroke angle. An in-house created graphical user interface was used to vary the voltage of the drive signal sent to the piezoelectric actuator which determined the wing stroke angle. The Air Force Institute of Technology baseline 50 mm wing was compared to wings manufactured with 55, 60, 65, and 70 mm spans, while maintaining a constant aspect ratio. Tests were conducted in a vacuum chamber at air densities between 0.5% and 100% of atmospheric pressure. Increasing the wingspan increased the wing’s weight, which reduced the first natural frequency; and did not result in an increase in vertical force over the baseline 50 mm wing. However, if the decrease in natural frequency corresponding to the increased wing span was counteracted by increasing the thickness of the joint material in the linkage mechanism, vertical force production increased over the baseline wing planform. Of the wings built with the more robust flapping mechanism, the 55 mm wing span produced 95% more vertical force at a 26% higher flapping frequency, while the 70 mm wing span produced 165% more vertical force at a 10% lower frequency than the Air Force Institute of Technology baseline wing. Negligible forces and moments were measured at vacuum, where the wing exhibited predominantly inertial motion, revealing flight forces measured in atmosphere are almost wholly limited to interaction with the surrounding air. Lastly, there was a rough correlation between Reynolds number and vertical force, indicating Reynolds number is a useful modelling parameter to predict lift and corresponding aerodynamic coefficients for a specific wing design.

show abstract

Closed-Loop Control of a Constrained, Resonant-Flapping Micro Air Vehicle

Cited by 2 publications

References 10 publications

Varying Reynolds Number of Biomimetic Flapping Wing By Changing Air Density and Wing Length

Varying Reynolds Number of Biomimetic Flapping Wing By Changing Air Density and Wing Length

Investigation into Reynolds number effects on a biomimetic flapping wing

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