Active and passive stabilization of body pitch in insect flight

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.

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Insect-like flapping wing mechanism based on a double spherical Scotch yoke

Journal of The Royal Society Interface ◽

10.1098/rsif.2005.0031 ◽

2005 ◽

Vol 2 (3) ◽

pp. 223-235 ◽

Cited By ~ 36

Author(s):

Cezary Galiński ◽

Rafał Żbikowski

Keyword(s):

Insect Flight ◽

Micro Air Vehicles ◽

Flapping Wing ◽

Controlled Study ◽

Concept Design ◽

Test Bed ◽

Insect Wing ◽

Flying Insects ◽

Adjustable Mechanism ◽

Air Vehicles

We describe the rationale, concept, design and implementation of a fixed-motion (non-adjustable) mechanism for insect-like flapping wing micro air vehicles in hover, inspired by two-winged flies (Diptera). This spatial (as opposed to planar) mechanism is based on the novel idea of a double spherical Scotch yoke. The mechanism was constructed for two main purposes: (i) as a test bed for aeromechanical research on hover in flapping flight, and (ii) as a precursor design for a future flapping wing micro air vehicle. Insects fly by oscillating (plunging) and rotating (pitching) their wings through large angles, while sweeping them forwards and backwards. During this motion the wing tip approximately traces a ‘figure-of-eight’ or a ‘banana’ and the wing changes the angle of attack (pitching) significantly. The kinematic and aerodynamic data from free-flying insects are sparse and uncertain, and it is not clear what aerodynamic consequences different wing motions have. Since acquiring the necessary kinematic and dynamic data from biological experiments remains a challenge, a synthetic, controlled study of insect-like flapping is not only of engineering value, but also of biological relevance. Micro air vehicles are defined as flying vehicles approximately 150 mm in size (hand-held), weighing 50–100 g, and are developed to reconnoitre in confined spaces (inside buildings, tunnels, etc.). For this application, insect-like flapping wings are an attractive solution and hence the need to realize the functionality of insect flight by engineering means. Since the semi-span of the insect wing is constant, the kinematics are spatial; in fact, an approximate figure-of-eight/banana is traced on a sphere. Hence a natural mechanism implementing such kinematics should be (i) spherical and (ii) generate mathematically convenient curves expressing the figure-of-eight/banana shape. The double spherical Scotch yoke design has property (i) by definition and achieves (ii) by tracing spherical Lissajous curves.

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Hawkmoths use wingstroke-to-wingstroke frequency modulation for aerial recovery to vortex ring perturbations

10.1101/2020.12.07.413781 ◽

2020 ◽

Author(s):

Jeff Gau ◽

Ryan Gemilere ◽

James Lynch ◽

Nick Gravish ◽

Simon Sponberg ◽

...

Keyword(s):

Frequency Modulation ◽

High Speed ◽

Insect Flight ◽

Control Strategies ◽

Flapping Wing ◽

Wingbeat Frequency ◽

Mechanical Constraints ◽

Power And Control ◽

Long Time ◽

And Control

AbstractCentimeter-scale fliers that combine wings with springy elements must contend with the high power requirements and mechanical constraints of flapping wing flight. Insects utilize elastic energy exchange to reduce the inertial costs of flapping wing flight and potentially match wingbeat frequencies to a mechanical resonance. Flying at resonance may be energetically favorable under steady conditions, but it is difficult to modulate the frequency of a resonant system. Evidence suggests that insects utilize frequency modulation over long time scales to adjust aerodynamic forces, but it remains an open question the extent to which insects can modulate frequency on the wingstroke-to-wingstroke timescale. If wingbeat frequencies deviate from resonance, the musculature must work against the elastic flight system, thereby potentially increasing energetic costs. To assess how insects address the simultaneous needs for power and control, we tested the capacity for wingstroke-to-wingstroke wingbeat frequency modulation by perturbing free hovering Manduca sexta with vortex rings while recording high-speed video at 2000 fps. Because hawkmoth flight muscles are synchronous, there is at least the potential for the nervous system to modulate frequency on each wingstroke. We observed ± 16% wingbeat frequency modulation in just a few wing strokes. Via instantaneous phase analysis of wing kinematics, we found that over 85% of perturbation responses required active changes in motor input frequency. Unlike their robotic counterparts that explicitly abdicate frequency modulation in favor of energy efficiency, we find that wingstroke-to-wingstroke frequency modulation is an underappreciated control strategies that complements other strategies for maneuverability and stability in insect flight.

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Anatomical Study of Insect Flight Structure

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.461.31 ◽

2013 ◽

Vol 461 ◽

pp. 31-36

Author(s):

Cheng Bin Ge ◽

Ai Hong Ji ◽

Tao Han ◽

Chang Long Li

Keyword(s):

Insect Flight ◽

Three Dimensional ◽

Anatomical Study ◽

Flapping Wing ◽

Long Distance ◽

Flying Insects ◽

Theoretical Support ◽

Flight Mode ◽

Aerial Vehicle ◽

Flight Parameters

Compared with the fixed-wing and rotary-wing aerial vehicle, the bionic ornithopter has unique advantages in flying maneuverability and flexibilities, becoming one of the focuses of current researches. Because of their high speeds, long distance flight sand low energy consumptions, more and more attentions has been paid to flying insects. Their unique physical structures and flight modes will enlighten the bionic ornithopter. In this paper, four insects flight-related muscle biological structures were dissected to specify the effects of the muscles. Then the flapping wing behavior of two of these insects was tested to guide for design of the bionic ornithopter. The anatomic results showed that they commonly own the dorsoventral muscles, whose weight proportions increase with their body wall thickness. The three-dimensional flapping traces of Dragonflies and Uangs are respectively 8-shape and resemble-8-shape. With combines of anatomy and flapping wing behavior test, the dorsoventral muscle and the tergal longitudinal muscle affect some flight parameters (flapping wing frequency, flapping wing angle, flapping wing movement, etc.). But these flight parameters changes were not sure entirely caused by the muscles. The study of insect physiology structure and flight mode not only can help the further understanding of the production mechanism of high-lift when insects flying, but also can provide theoretical support for development of the bionic ornithopter.

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Active Control of Greenhouse Climate Enhances Papaya Growth and Yield at an Affordable Cost

Agronomy ◽

10.3390/agronomy11020378 ◽

2021 ◽

Vol 11 (2) ◽

pp. 378

Author(s):

Irene Salinas ◽

Juan José Hueso ◽

Julián Cuevas

Keyword(s):

Active Control ◽

Skin Color ◽

Natural Ventilation ◽

Control Strategies ◽

Soluble Solids ◽

Growth And Yield ◽

Climate Control ◽

Tropical Fruit ◽

Greenhouse Climate ◽

Solids Content

Papaya is a tropical fruit crop that in subtropical regions depends on protected cultivation to fulfill its climate requirements and remain productive. The aim of this work was to compare the profitability of different climate control strategies in greenhouses located in subtropical areas of southeast Spain. To do so, we compared papayas growing in a greenhouse equipped with active climate control (ACC), achieved by cooling and heating systems, versus plants growing in another greenhouse equipped with passive climate control (PCC), consisting of only natural ventilation through zenithal and lateral windows. The results showed that ACC favored papaya plant growth; flowering; fruit set; and, consequently, yields, producing more and heavier fruits at an affordable cost. Climate control strategies did not significantly improve fruit quality, specifically fruit skin color, acidity, and total soluble solids content. In conclusion, in the current context of prices, an active control of temperature and humidity inside the greenhouse could be a more profitable strategy in subtropical regions where open-air cultivation is not feasible.

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FLAPPING WING DEVICES FOR MARS EXPLORATION

Proceedings of the Canadian Engineering Education Association (CEEA) ◽

10.24908/pceea.v0i0.4035 ◽

2011 ◽

Author(s):

Asier Ania ◽

Dominique Poirel ◽

Marie-Josée Potvin ◽

Steeve Montminy

Keyword(s):

Reynolds Number ◽

Insect Flight ◽

Low Reynolds Number ◽

Flapping Wing ◽

Low Density ◽

Mars Exploration ◽

Unsteady Aerodynamic ◽

Aerial Vehicle ◽

Low Reynolds

The use of an aerial vehicle would greatly enhance the domain of exploration on Mars. The main constraint in such a design would be the extreme Martian environment. The low-density atmosphere suggests the use of a low Reynolds number flight regime modeled after flapping wing insect flight. This flapping wing flight employs several unsteady aerodynamic mechanisms; delayed stall, wake capture, and rotational mechanisms. Two prototypes, a flapping wing and a rotary-flapping wing hybrid, have been built and will be tested in order to quantify the 'overall lift' generated and allow us to evaluate the efficacy of flapping wing flight on Mars.

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The Use of Damping Based Semi-Active Control Algorithms in the Mechanical Smart-Spring System

Journal of Vibration and Acoustics ◽

10.1115/1.4038034 ◽

2017 ◽

Vol 140 (2) ◽

Cited By ~ 1

Author(s):

Wander Gustavo Rocha Vieira ◽

Fred Nitzsche ◽

Carlos De Marqui

Keyword(s):

Active Control ◽

Control Algorithm ◽

Control Strategies ◽

Vibration Reduction ◽

Flow Analysis ◽

Coupled Systems ◽

Control Technique ◽

Control Algorithms ◽

Control Techniques ◽

Spring Mechanism

In recent decades, semi-active control strategies have been investigated for vibration reduction. In general, these techniques provide enhanced control performance when compared to traditional passive techniques and lower energy consumption if compared to active control techniques. In semi-active concepts, vibration attenuation is achieved by modulating inertial, stiffness, or damping properties of a dynamic system. The smart spring is a mechanical device originally employed for the effective modulation of its stiffness through the use of semi-active control strategies. This device has been successfully tested to damp aeroelastic oscillations of fixed and rotary wings. In this paper, the modeling of the smart spring mechanism is presented and two semi-active control algorithms are employed to promote vibration reduction through enhanced damping effects. The first control technique is the smart-spring resetting (SSR), which resembles resetting control techniques developed for vibration reduction of civil structures as well as the piezoelectric synchronized switch damping on short (SSDS) technique. The second control algorithm is referred to as the smart-spring inversion (SSI), which presents some similarities with the synchronized switch damping (SSD) on inductor technique previously presented in the literature of electromechanically coupled systems. The effects of the SSR and SSI control algorithms on the free and forced responses of the smart-spring are investigated in time and frequency domains. An energy flow analysis is also presented in order to explain the enhanced damping behavior when the SSI control algorithm is employed.

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