scholarly journals Embodied linearity of speed control in Drosophila melanogaster

2012 ◽  
Vol 9 (77) ◽  
pp. 3260-3267 ◽  
Author(s):  
V. Medici ◽  
S. N. Fry
Keyword(s):  
Control Strategy ◽  
High Speed ◽  
Hierarchical Control ◽  
Speed Control ◽  
Micro Air Vehicles ◽  
The Body ◽  
Flight Speed ◽  
Free Flight ◽  
Body Angle ◽  
Visual Speed

Fruitflies regulate flight speed by adjusting their body angle. To understand how low-level posture control serves an overall linear visual speed control strategy, we visually induced free-flight acceleration responses in a wind tunnel and measured the body kinematics using high-speed videography. Subsequently, we reverse engineered the transfer function mapping body pitch angle onto flight speed. A linear model is able to reproduce the behavioural data with good accuracy. Our results show that linearity in speed control is realized already at the level of body posture-mediated speed control and is therefore embodied at the level of the complex aerodynamic mechanisms of body and wings. Together with previous results, this study reveals the existence of a linear hierarchical control strategy, which can provide relevant control principles for biomimetic implementations, such as autonomous flying micro air vehicles.

The mechanics of flight in the hawkmoth Manduca sexta. I. Kinematics of hovering and forward flight.

1997 ◽  
Vol 200 (21) ◽  
pp. 2705-2722 ◽  
Author(s):  
A P Willmott ◽  
C P Ellington
Keyword(s):  
Manduca Sexta ◽  
High Speed ◽  
Time Course ◽  
The Body ◽  
Forward Speed ◽  
Plane Angle ◽  
Free Flight ◽  
Body Angle ◽  
Distal Half ◽  
Angle Of Rotation

High-speed videography was used to record sequences of individual hawkmoths in free flight over a range of speeds from hovering to 5 ms-1. At each speed, three successive wingbeats were subjected to a detailed analysis of the body and wingtip kinematics and of the associated time course of wing rotation. Results are presented for one male and two female moths. The clearest kinematic trends accompanying increases in forward speed were an increase in stroke plane angle and a decrease in body angle. The latter may have resulted from a slight dorsal shift in the area swept by the wings as the supination position became less ventral with increasing speed. These trends were most pronounced between hovering and 3 ms-1, and the changes were gradual; there was no distinct gait change of the kind observed in some vertebrate fliers. The wing rotated as two functional sections: the hindwing and the portion of the forewing with which it is in contact, and the distal half of the forewing. The latter displayed greater fluctuation in the angle of rotation, especially at the lower speeds. As forward speed increased, the discrepancy between the rotation angles of the two halfstrokes, and of the two wing sections, became smaller. The downstroke wing torsion was set early in the halfstroke and then held constant during the translational phase.

scholarly journals Kinematics Measurement and Power Requirements of Fruitflies at Various Flight Speeds

Energies ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 4271
Author(s):  
Hao Jie Zhu ◽  
Mao Sun
Keyword(s):  
The Body ◽  
Flight Speed ◽  
Specific Power ◽  
Flight Performance ◽  
Wingbeat Frequency ◽  
Body Angle ◽  
Flying Insects ◽  
Speed Range ◽  
Full Speed ◽  
Stroke Amplitude

Energy expenditure is a critical characteristic in evaluating the flight performance of flying insects. To investigate how the energy cost of small-sized insects varies with flight speed, we measured the detailed wing and body kinematics in the full speed range of fruitflies and computed the aerodynamic forces and power requirements of the flies. As flight speed increases, the body angle decreases and the stroke plane angle increases; the wingbeat frequency only changes slightly; the geometrical angle of attack in the middle upstroke increases; the stroke amplitude first decreases and then increases. The mechanical power of the fruitflies at all flight speeds is dominated by aerodynamic power (inertial power is very small), and the magnitude of aerodynamic power in upstroke increases significantly at high flight speeds due to the increase of the drag and the flapping velocity of the wing. The specific power (power required for flight divided by insect weigh) changes little when the advance ratio is below about 0.45 and afterwards increases sharply. That is, the specific power varies with flight speed according to a J-shaped curve, unlike those of aircrafts, birds and large-sized insects which vary with flight speed according to a U-shaped curve.

Relationships between body mass, motor output and flight variables during free flight of juvenile and mature adult locusts, Schistocerca gregaria

2000 ◽  
Vol 203 (18) ◽  
pp. 2723-2735 ◽  
Author(s):  
H. Fischer ◽  
W. Kutsch
Keyword(s):  
Body Mass ◽  
Schistocerca Gregaria ◽  
Flight Speed ◽  
Free Flight ◽  
Wingbeat Frequency ◽  
Motor Patterns ◽  
Mature Adult ◽  
Body Angle ◽  
Flight System ◽  
Functional Relationships

Little information is available about how the adult locust flight system manages to match the aerodynamic demands that result from an increase in body mass during postmoult maturation. In Schistocerca gregaria of both sexes, flight variables, including flight speed, ascent angle and body angle, were investigated under closed-loop conditions (i.e. during free flight) as a function of adult maturation. Motor patterns were examined by telemetric electromyography in juvenile and adult mature animals of both sexes. Functional relationships between particular flight variables were investigated by additional loading of the animals and by reductions in wing area. The results indicate that an increase in flight speed as the flight system matures enables it to match the aerodynamic demands resulting from increases in body mass. Furthermore, the data suggest that this postmoult increase in flight speed is not simply a consequence of the increase in wingbeat frequency observed during maturation. The instantaneous body angle during flight is controlled mainly by aerodynamic output from the wings. In addition, the mean body angle decreases during maturation in both sexes, and this may play an important part in the directional control of the resultant flight force vector.

scholarly journals Flight kinematics of black-billed magpies and pigeons over a wide range of speeds

1996 ◽  
Vol 199 (2) ◽  
pp. 263-280 ◽  
Author(s):  
B Tobalske ◽  
K Dial
Keyword(s):  
Wind Tunnel ◽  
Aspect Ratio ◽  
Vortex Ring ◽  
High Speed ◽  
Columba Livia ◽  
Flight Speed ◽  
Body Angle ◽  
Scaling Hypothesis ◽  
Wide Range ◽  
Mechanical Power Output

To investigate how birds that differ in morphology change their wing and body movements while flying at a range of speeds, we analyzed high-speed (60 Hz) video tapes of black-billed magpies (Pica pica) flying at speeds of 4-14 m s-1 and pigeons (Columba livia) flying at 6-20 m s-1 in a wind-tunnel. Pigeons had higher wing loading and higher-aspect-ratio wings compared with magpies. Both species alternated phases of steady-speed flight with phases of acceleration and deceleration, particularly at intermediate flight speeds. The birds modulated their wingbeat kinematics among these phases and frequently exhibited non-flapping phases while decelerating. Such modulation in kinematics during forward flight is typical of magpies but not of pigeons in the wild. The behavior of the pigeons may have been a response to the reduced power costs for flight in the closed wind-tunnel relative to those for free flight at similar speeds. During steady-speed flight, wingbeat frequency did not change appreciably with increasing flight speed. Body angle relative to the horizontal, the stroke-plane angles of the wingtip and wrist relative to the horizontal and the angle describing tail spread at mid-downstroke all decreased with increasing flight speed, thereby illustrating a shift in the dominant function of wing flapping from weight support at slow speeds to positive thrust at fast speeds. Using wingbeat kinematics to infer lift production, it appeared that magpies used a vortex-ring gait during steady-speed flight at all speeds whereas pigeons used a vortex-ring gait at 6 and 8 m s-1, a transitional vortex-ring gait at 10 m s-1, and a continuous-vortex gait at faster speeds. Both species used a vortex-ring gait for acceleration and a continuous-vortex gait or a non-flapping phase for deceleration during flight at intermediate wind-tunnel speeds. Pigeons progressively flexed their wings during glides as flight speed increased but never performed bounds. Wingspan during glides in magpies did not vary with flight speed, but the percentage of bounds among non-flapping intervals increased with speed from 10 to 14 m s-1. The use of non-flapping wing postures seemed to be related to the gaits used during flapping and to the aspect ratio of the wings. We develop an 'adverse-scaling' hypothesis in which it is proposed that the ability to reduce metabolic and mechanical power output using flap-bounding flight at fast flight speeds is scaled negatively with body mass. This represents an alternative to the 'fixed-gear' hypothesis previously suggested by other authors to explain the use of intermittent flight in birds. Future comparative studies in the field would be worthwhile, especially if instantaneous flight speeds and within-wingbeat kinematics were documented; new studies in the laboratory should involve simultaneous recording of wing kinematics and aerodynamic forces on the wing.

scholarly journals Flying in reverse: kinematics and aerodynamics of a dragonfly in backward free flight

2018 ◽  
Vol 15 (143) ◽  
pp. 20180102 ◽  
Author(s):  
Ayodeji T. Bode-Oke ◽  
Samane Zeyghami ◽  
Haibo Dong
Keyword(s):  
High Speed ◽  
Aerodynamic Force ◽  
Force Production ◽  
Leading Edge ◽  
The Body ◽  
Body Posture ◽  
Immersed Boundary ◽  
Reconstruction Method ◽  
Free Flight ◽  
The Us

In this study, we investigated the backward free flight of a dragonfly, accelerating in a flight path inclined to the horizontal. The wing and body kinematics were reconstructed from the output of three high-speed cameras using a template-based subdivision surface reconstruction method, and numerical simulations using an immersed boundary flow solver were conducted to compute the forces and visualize the flow features. During backward flight, the dragonfly maintained an upright body posture of approximately 90° relative to the horizon. The upright body posture was used to reorient the stroke plane and the flight force in the global frame; a mechanism known as ‘force vectoring’ which was previously observed in manoeuvres of other flying animals. In addition to force vectoring, we found that while flying backward, the dragonfly flaps its wings with larger angles of attack in the upstroke (US) when compared with forward flight. Also, the backward velocity of the body in the upright position enhances the wings' net velocity in the US. The combined effect of the angle of attack and wing net velocity yields large aerodynamic force generation in the US, with the average magnitude of the force reaching values as high as two to three times the body weight. Corresponding to these large forces was the presence of a strong leading edge vortex (LEV) at the onset of US which remained attached up until wing reversal. Finally, wing–wing interaction was found to enhance the aerodynamic performance of the hindwings (HW) during backward flight. Vorticity from the forewings’ trailing edge fed directly into the HW LEV to increase its circulation and enhance force production.

Biology and Physics of locust flight II. Flight performance of the desert locust ( Schistocerca gregaria )

1956 ◽  
Vol 239 (667) ◽  
pp. 459-510 ◽  
Keyword(s):  
Steady State ◽  
Time Course ◽  
Harmonic Oscillation ◽  
The Body ◽  
Horizontal Wind ◽  
Vertical Force ◽  
Flight Performance ◽  
Free Flight ◽  
Stroke Frequency ◽  
Body Angle

The main purpose is to analyze how a number of wing-stroke parameters are related to the lift (average vertical force) and thrust (average horizontal force) produced by the insect under well defined aerodynamic conditions. The locust was suspended from a complicated balance and flew against a uniform horizontal wind from an open-jet wind tunnel. The wind speed was automatically adjusted to the preferred flying speed (air speed), i.e. the speed at which the thrust equals the extra-to-wing drag . The lift was measured as the apparent reduction in weight; it is given as a percentage of the weight which the individual would have if it had flown for about one hour, was full-grown and well fed but, if a female, with undeveloped eggs ( = basic weight). This figure is the relative lift, and it is used because the actual weight changes much with age, feeding, sexual development, etc., while the dimensions of the flight motor remain constant. The angle between the wind and the long body axis is the body angle and was chosen by the observer or by the insect itself. Most experiments took place at 30° C (constant temperature room), but series were run at the upper and lower limits for flight, including experiments with small flocks of locusts suspended from a roundabout. The rate of evaporation of water from the thorax was kept constant. In a large number of individuals sustained steady-state flight was studied; at regular intervals a set of simultaneous readings were taken consisting of the lift, the speed, the body angle, the stroke frequency, the extreme angular positions of the wings, and of the inclination to the vertical of the stroke planes. In addition, the angular movements of the entire wings relative to the body were estimated from slow-motion films. The results are seen in §§4 to 7. The frequency distribution of the relative lift has its maximum about 100 %, showing that, in this respect, the flight comes near to free flight. It varied from 35 to 175 %, i.e. about five times. During continuous horizontal flight the flying speed was 3•5+ 0•1 m/s and may increase to 4•2 m/s in free flight. At larger lifts (climbing) the steady-state speed could reach 4•5 m/s. During the first minutes the speed was often 4•5 to 5•0 m/s, the maximum observed being 5•5 m/s. No locust lifted its own weight at speeds less than 2•5 m/s. The power necessary to overcome the extra-to-wing drag only corresponds to 1 to 3 % of the total metabolic rate. The effect of altering the body angle is fundamentally different from that of altering the pitch of an aircraft; the lift is controlled and kept constant by the locust and proved to be independent of alterations in the body angle amounting to as much as 20°. This is the basis for the technique and for the treatment of the results. In spite of the large variations in lift, the following stroke parameters varied little or not at all: the stroke angles , the stroke-plane angles , the middle position of the wings , and the time course of the angular movement of the entire wing, y = y(t). The latter function deviates considerably from a simple harmonic oscillation. According to figure II, 20, the average points are determined with an accuracy of better than + 1 %, permitting graphical differentiation. The stroke frequency was rather constant but increased with the reflexly controlled lift, contrary to Chadwick’s experiments on Drosophila , and decreased with increasing size, according to Sotavalta’s findings in other insects. The maximal changes were small, however, amounting to 8 % (lift) and 15 % (size) respectively. The flight performance and the stroke parameters were independent of changes in air temperature (no radiant heat) within 25 to 35° G, although the pterothorax is subjected to similar changes. Sustained flight does not take place below 25° C and above 35° G, but short performances were observed between 22 and 24° C as well as above 37° C. The great variation in lift could not be explained by changes in the measured stroke parameters, and by analogy with a variable-pitch propeller, it must be caused by differences in wing twisting 0(r,t). It was also found that lift and thrust varied in a more intricate way than in a simple actuator disk. The regularity of the stroke and its independence of temperature makes it possible to define a standard stroke , making it easy to compare a given performance with the normal.

Mechanics of Forward Flight in Bumblebees: I. Kinematics and Morphology

1990 ◽  
Vol 148 (1) ◽  
pp. 19-52 ◽  
Author(s):  
R. DUDLEY ◽  
C. P. ELLINGTON
Keyword(s):  
High Speed ◽  
Morphological Analysis ◽  
Angle Of Attack ◽  
Three Dimensional ◽  
Free Flight ◽  
Forward Flight ◽  
Body Angle ◽  
Dimensional Reconstruction ◽  
High Speed Cinematography ◽  
Wing Tip

Using high-speed cinematography, bumblebees in free flight were filmed over a range of forward airspeeds. A detailed description of the wing tip and body kinematics was obtained from a three-dimensional reconstruction of the twodimensional film image. A technique for determining quantitatively the angle of attack of the wing was developed. Kinematic parameters found to vary consistently with airspeed were body angle, stroke plane angle, geometrical angle of attack, and rotational angles of the wings at the ends of half-strokes. Results of a morphological analysis of the wings and bodies of thoseinsects filmed in free flight are presented for use in later calculations of the lift and power requirements of forward flight.

scholarly journals On the So-called Constant-lift Reaction of Migratory Locusts

1989 ◽  
Vol 147 (1) ◽  
pp. 111-124 ◽  
Author(s):  
WOLFRAM ZARNACK ◽  
MICHAEL WORTMANN
Keyword(s):  
Body Weight ◽  
Wind Speed ◽  
Wind Tunnel ◽  
Force Transducer ◽  
The Body ◽  
Flight Speed ◽  
Body Angle ◽  
Level Flight ◽  
Tethered Flight ◽  
Thrust Measurement

1. Locusts were fastened to a force transducer in front of a wind tunnel to measure their lift and thrust during tethered flight heading into the wind. The thrust measurement was used to adapt the wind speed to the flight speed of the animals. Thus, the locusts could choose their flight speed freely in the range 0.5–7ms−1. 2. At light intensities of about 0.02 lx (twilight), the locusts generally produced a maximum lift greater than 100% of their body weight. 3. A miniature motor mounted on the force transducer could alter the body angle of the locusts without further interference. Lift was found to be influenced by body angle. No ‘constant-lift reaction’ evoked by exteroceptive information of the aerodynamic flow was found. 4. Flight speed was almost independent of the imposed body angle. 5. Generally, a flight speed of about 3 m s−1 was necessary for level flight. There was no further correlation between lift and flight speed.

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