Active Control of the Hinge of a Flapping Wing with Electrostatic Sticking to Modify the Passive Pitching Motion

2016 ◽  
pp. 153-174
Author(s):  
Hugo Peters ◽  
Qi Wang ◽  
Hans Goosen ◽  
Fred van Keulen
Keyword(s):  
Active Control ◽  
Flapping Wing ◽  
Pitching Motion

scholarly journals Quasi-Steady versus Navier–Stokes Solutions of Flapping Wing Aerodynamics

Fluids ◽  
2018 ◽  
Vol 3 (4) ◽  
pp. 81 ◽  
Author(s):  
Jeremy Pohly ◽  
James Salmon ◽  
James Bluman ◽  
Kabilan Nedunchezian ◽  
Chang-kwon Kang
Keyword(s):  
Stokes Equations ◽  
Aerodynamic Force ◽  
Lift Coefficient ◽  
Three Dimensional ◽  
Fruit Fly ◽  
Flapping Wing ◽  
Navier Stokes ◽  
Pitching Motion ◽  
Navier Stokes Equations ◽  
Wing Motion

Various tools have been developed to model the aerodynamics of flapping wings. In particular, quasi-steady models, which are considerably faster and easier to solve than the Navier–Stokes equations, are often utilized in the study of flight dynamics of flapping wing flyers. However, the accuracy of the quasi-steady models has not been properly documented. The objective of this study is to assess the accuracy of a quasi-steady model by comparing the resulting aerodynamic forces against three-dimensional (3D) Navier–Stokes solutions. The same wing motion is prescribed at a fruit fly scale. The pitching amplitude, axis, and duration are varied. Comparison of the aerodynamic force coefficients suggests that the quasi-steady model shows significant discrepancies under extreme pitching motions, i.e., the pitching motion is large, quick, and occurs about the leading or trailing edge. The differences are as large as 1.7 in the cycle-averaged lift coefficient. The quasi-steady model performs well when the kinematics are mild, i.e., the pitching motion is small, long, and occurs near the mid-chord with a small difference in the lift coefficient of 0.01. Our analysis suggests that the main source for the error is the inaccuracy of the rotational lift term and the inability to model the wing-wake interaction in the quasi-steady model.

scholarly journals Active and passive stabilization of body pitch in insect flight

2013 ◽  
Vol 10 (85) ◽  
pp. 20130237 ◽  
Author(s):  
Leif Ristroph ◽  
Gunnar Ristroph ◽  
Svetlana Morozova ◽  
Attila J. Bergou ◽  
Song Chang ◽  
...  
Keyword(s):  
Active Control ◽  
Insect Flight ◽  
Control Strategies ◽  
Fruit Flies ◽  
Flapping Wing ◽  
Passive Stability ◽  
Flying Insects ◽  
Body Drag ◽  
Instability Growth ◽  
Passive Stabilization

Flying insects have evolved sophisticated sensory–motor systems, and here we argue that such systems are used to keep upright against intrinsic flight instabilities. We describe a theory that predicts the instability growth rate in body pitch from flapping-wing aerodynamics and reveals two ways of achieving balanced flight: active control with sufficiently rapid reactions and passive stabilization with high body drag. By glueing magnets to fruit flies and perturbing their flight using magnetic impulses, we show that these insects employ active control that is indeed fast relative to the instability. Moreover, we find that fruit flies with their control sensors disabled can keep upright if high-drag fibres are also attached to their bodies, an observation consistent with our prediction for the passive stability condition. Finally, we extend this framework to unify the control strategies used by hovering animals and also furnish criteria for achieving pitch stability in flapping-wing robots.

An Introduction to Flapping Wing Aerodynamics

2013 ◽  
Author(s):  
Wei Shyy ◽  
Hikaru Aono ◽  
Chang-kwon Kang ◽  
Hao Liu
Keyword(s):  
Flapping Wing ◽  
Wing Aerodynamics
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