scholarly journals Flies compensate for unilateral wing damage through modular adjustments of wing and body kinematics

2017 ◽  
Vol 7 (1) ◽  
pp. 20160103 ◽  
Author(s):  
Florian T. Muijres ◽  
Nicole A. Iwasaki ◽  
Michael J. Elzinga ◽  
Johan M. Melis ◽  
Michael H. Dickinson
Keyword(s):  
High Speed ◽  
Lateral Force ◽  
Wingbeat Frequency ◽  
Wing Motion ◽  
Roll Torque ◽  
Weight Support ◽  
Asymmetrical Pattern ◽  
Body Roll ◽  
Vertical Lift ◽  
Wing Damage

Using high-speed videography, we investigated how fruit flies compensate for unilateral wing damage, in which loss of area on one wing compromises both weight support and roll torque equilibrium. Our results show that flies control for unilateral damage by rolling their body towards the damaged wing and by adjusting the kinematics of both the intact and damaged wings. To compensate for the reduction in vertical lift force due to damage, flies elevate wingbeat frequency. Because this rise in frequency increases the flapping velocity of both wings, it has the undesired consequence of further increasing roll torque. To compensate for this effect, flies increase the stroke amplitude and advance the timing of pronation and supination of the damaged wing, while making the opposite adjustments on the intact wing. The resulting increase in force on the damaged wing and decrease in force on the intact wing function to maintain zero net roll torque. However, the bilaterally asymmetrical pattern of wing motion generates a finite lateral force, which flies balance by maintaining a constant body roll angle. Based on these results and additional experiments using a dynamically scaled robotic fly, we propose a simple bioinspired control algorithm for asymmetric wing damage.

Forewing asymmetries during auditory avoidance in flying locusts

1997 ◽  
Vol 200 (17) ◽  
pp. 2323-2335 ◽  
Author(s):  
J Dawson ◽  
K Dawson-Scully ◽  
D Robert ◽  
R. M. Robertson
Keyword(s):  
High Speed ◽  
Stimulus Onset ◽  
Wingbeat Frequency ◽  
Motor Patterns ◽  
Wing Kinematics ◽  
Roll Torque ◽  
High Speed Cinematography ◽  
Left And Right ◽  
The Asymmetry ◽  
Stroke Amplitude

Flying locusts orient to sounds in their environment. Sounds similar to those produced by echolocating bats cause a flying locust to change its flight path. We used high-speed cinematography and videography to study changes in body posture and wing kinematics of tethered locusts in response to stimulation with bat-like sounds. Locusts showed both negative and positive phonotaxis to this stimulus. Within a few wingbeats of stimulus onset (between 126 and 226ms), locusts deflected their abdomens to one side, and the angle of the left and right forewings with respect to the dorsal­ventral body axis became asymmetrical during the downstroke. This forewing asymmetry, in which the forewing on the inside of the turn became more depressed, ranged from 20 to 45° (37±9.7°, mean ± s.d.) and was correlated with the direction and magnitude of abdomen deflection, a measure of steering in tethered, flying locusts. Hindwing stroke angle asymmetries were minimal or non-existent after stimulation. Coincident with changes in forewing asymmetry and abdomen deflection was a decrease in stroke amplitude (19±6.5°) of the forewing on the inside of the attempted turn. Motor patterns from forewing first basalar (M97) muscles showed an asymmetry in the timing of left and right depressor activation that ranged from 10.4 to 1.6ms (4.23±2.85ms). The number of spikes per depressor burst increased to a maximum of three spikes in the muscle on the inside of the attempted turn, and depressor frequency (wingbeat frequency) increased by approximately 2Hz (2.17±0.26Hz). We suggest that the asymmetry in forewing first basalar activity is causally related to the asymmetry in the timing of the initiation of the downstroke, resulting in an asymmetry in the ranges of the stroke angles of the forewings, which would impart a roll torque to the locust. This would augment the steering torques generated by concurrent changes in the angle of attack of the fore- and hindwings and changes in abdomen position to effect rapid avoidance manoeuvres.

scholarly journals Wearable Vibration Sensor for Measuring the Wing Flapping of Insects

Sensors ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 593
Author(s):  
Ryota Yanagisawa ◽  
Shunsuke Shigaki ◽  
Kotaro Yasui ◽  
Dai Owaki ◽  
Yasuhiro Sugimoto ◽  
...  
Keyword(s):  
High Speed ◽  
Environmental Changes ◽  
Underlying Mechanism ◽  
Indirect Measurement ◽  
Feedback Mechanism ◽  
The Body ◽  
Vibration Sensor ◽  
Wingbeat Frequency ◽  
Film Sensor ◽  
Insect Wing

In this study, we fabricated a novel wearable vibration sensor for insects and measured their wing flapping. An analysis of insect wing deformation in relation to changes in the environment plays an important role in understanding the underlying mechanism enabling insects to dynamically interact with their surrounding environment. It is common to use a high-speed camera to measure the wing flapping; however, it is difficult to analyze the feedback mechanism caused by the environmental changes caused by the flapping because this method applies an indirect measurement. Therefore, we propose the fabrication of a novel film sensor that is capable of measuring the changes in the wingbeat frequency of an insect. This novel sensor is composed of flat silver particles admixed with a silicone polymer, which changes the value of the resistor when a bending deformation occurs. As a result of attaching this sensor to the wings of a moth and a dragonfly and measuring the flapping of the wings, we were able to measure the frequency of the flapping with high accuracy. In addition, as a result of simultaneously measuring the relationship between the behavior of a moth during its search for an odor source and its wing flapping, it became clear that the frequency of the flapping changed depending on the frequency of the odor reception. From this result, a wearable film sensor for an insect that can measure the displacement of the body during a particular behavior was fabricated.

scholarly journals Influence of hinge length and distribution number on the camber and cornering properties of a non-pneumatic tire

2020 ◽  
Vol 12 (12) ◽  
pp. 168781402098468
Author(s):  
Xianbin Du ◽  
Youqun Zhao ◽  
Yijiang Ma ◽  
Hongxun Fu
Keyword(s):  
Neural Network ◽  
Network Model ◽  
Adaptive Learning ◽  
High Speed ◽  
Back Propagation ◽  
Lateral Force ◽  
Learning Ability ◽  
Vehicle Performance ◽  
Neural Network Theory ◽  
Bp Neural Network Model

The camber and cornering properties of the tire directly affect the handling stability of vehicles, especially in emergencies such as high-speed cornering and obstacle avoidance. The structural and load-bearing mode of non-pneumatic mechanical elastic (ME) wheel determine that the mechanical properties of ME wheel will change when different combinations of hinge length and distribution number are adopted. The camber and cornering properties of ME wheel with different hinge lengths and distributions were studied by combining finite element method (FEM) with neural network theory. A ME wheel back propagation (BP) neural network model was established, and the additional momentum method and adaptive learning rate method were utilized to improve BP algorithm. The learning ability and generalization ability of the network model were verified by comparing the output values with the actual input values. The camber and cornering properties of ME wheel were analyzed when the hinge length and distribution changed. The results showed the variation of lateral force and aligning torque of different wheel structures under the combined conditions, and also provided guidance for the matching of wheel and vehicle performance.

scholarly journals High-Velocity Shear and Soft Friction at the Nanometer Scale

2021 ◽  
Vol 7 ◽  
Author(s):  
Per-Anders Thorén ◽  
Riccardo Borgani ◽  
Daniel Forchheimer ◽  
David B. Haviland
Keyword(s):  
High Speed ◽  
Surface Deformation ◽  
Soft Materials ◽  
Lateral Force ◽  
Velocity Shear ◽  
Polymer Materials ◽  
Amplitude Dependence ◽  
Dynamic Force ◽  
Stick Slip ◽  
Soft Polymer

We study high-speed friction on soft polymer materials by measuring the amplitude dependence of cyclic lateral forces on the atomic force microscope (AFM) tip as it slides on the surface with fixed contact force. The resulting dynamic force quadrature curves separate the elastic and viscous contributions to the lateral force, revealing a transition from stick-slip to free-sliding motion as the velocity increases. We explain force quadratures and describe how they are measured, and we show results for a variety of soft materials. The results differ substantially from the measurements on hard materials, showing hysteresis in the force quadrature curves that we attribute to the finite relaxation time of viscoelastic surface deformation.

Dynamic Analysis of Steering Bogies

2016 ◽  
pp. 524-579 ◽  
Author(s):  
Arun K. Samantaray ◽  
Smitirupa Pradhan
Keyword(s):  
High Speed ◽  
Ride Comfort ◽  
Lateral Force ◽  
Rolling Stock ◽  
Wheel Wear ◽  
Active Steering ◽  
Load Fluctuation ◽  
Speed Up ◽  
Turning Radius ◽  
Secondary Suspension

Running times of high-speed rolling stock can be reduced by increasing running speed on curved portions of the track. During curving, flange contact causes large lateral force, high frequency noises, flange wears and wheel load fluctuation at transition curves. To avoid derailment and hunting, and to improve ride comfort, i.e., to improve the curving performances at high speed, forced/active steering bogie design is studied in this chapter. The actively steered bogie is able to negotiate cant excess and deficiency. The bogie performance is studied on flexible irregular track with various levels of cant and wheel wear. The bogie and coach assembly models are developed in Adams VI-Rail software. This design can achieve operating speed up to 360 km/h on standard gauge ballasted track with 150mm super-elevation, 4km turning radius and 460m clothoid type entry curve design. The key features of the designed bogie are the graded circular wheel profiles, air-spring secondary suspension, chevron springs in the primary suspension, anti-yaw and lateral dampers, and the steering linkages.

scholarly journals Foraging at the edge of the world: low-altitude, high-speed manoeuvering in barn swallows

2016 ◽  
Vol 371 (1704) ◽  
pp. 20150391 ◽  
Author(s):  
Douglas R. Warrick ◽  
Tyson L. Hedrick ◽  
Andrew A. Biewener ◽  
Kristen E. Crandell ◽  
Bret W. Tobalske
Keyword(s):  
Wind Speed ◽  
High Speed ◽  
Ground Effect ◽  
Natural State ◽  
Wingbeat Frequency ◽  
High Speeds ◽  
Aerial Insectivores ◽  
Video Systems ◽  
Shear Gradient ◽  
Barn Swallows

While prior studies of swallow manoeuvering have focused on slow-speed flight and obstacle avoidance in still air, swallows survive by foraging at high speeds in windy environments. Recent advances in field-portable, high-speed video systems, coupled with precise anemometry, permit measures of high-speed aerial performance of birds in a natural state. We undertook the present study to test: (i) the manner in which barn swallows ( Hirundo rustica ) may exploit wind dynamics and ground effect while foraging and (ii) the relative importance of flapping versus gliding for accomplishing high-speed manoeuvers. Using multi-camera videography synchronized with wind-velocity measurements, we tracked coursing manoeuvers in pursuit of prey. Wind speed averaged 1.3–2.0 m s −1 across the atmospheric boundary layer, exhibiting a shear gradient greater than expected, with instantaneous speeds of 0.02–6.1 m s −1 . While barn swallows tended to flap throughout turns, they exhibited reduced wingbeat frequency, relying on glides and partial bounds during maximal manoeuvers. Further, the birds capitalized on the near-earth wind speed gradient to gain kinetic and potential energy during both flapping and gliding turns; providing evidence that such behaviour is not limited to large, fixed-wing soaring seabirds and that exploitation of wind gradients by small aerial insectivores may be a significant aspect of their aeroecology. This article is part of the themed issue ‘Moving in a moving medium: new perspectives on flight'.

Experimental studies of load characteristics of bogie frames for 350 km/h EMUs

2011 ◽  
Vol 226 (2) ◽  
pp. 216-227 ◽  
Author(s):  
Z Ren ◽  
S Sun ◽  
Q Li ◽  
Z Liu
Keyword(s):  
High Speed ◽  
Experimental Studies ◽  
Lateral Force ◽  
Load Spectrum ◽  
Dynamic Stresses ◽  
Dynamic Coefficients ◽  
Sample Data ◽  
Load Characteristics ◽  
Amplitude Level ◽  
Track Irregularities

In this paper,methods to measure the axle spring load, trailing arm seat lateral force and dynamic stresses of powered and non-powered bogies of a 350 km/h electrical-multi-unit (EMU) are presented. The dynamic amplitude and Hilbert transform of the sample data are used to investigate the characteristics of the forces and the stresses for the EMU running on typical sections including high-speed division, turnout zone, curves, and depot entrance. The load spectrum is then introduced to survey the amplitude level and the number of occurrence of the loads and stresses. Dynamic coefficients of the loads are compared with the recommended values in the Code UIC615-4. The effects of track irregularities and vibrations of gear boxes and motors on the loads and stresses are investigated and the measured loads are classified into six types according to effects of forces on the bogie's movement. The characteristics of the measured loads are useful to establish load conditions for laboratory tests of bogie’s fatigue assessment.

scholarly journals A novel mouse running wheel that senses individual limb forces: biomechanical validation and in vivo testing

2012 ◽  
Vol 113 (4) ◽  
pp. 627-635 ◽  
Author(s):  
Grahm C. Roach ◽  
Mangesh Edke ◽  
Timothy M. Griffin
Keyword(s):  
High Speed ◽  
Wheel Running ◽  
Screening Method ◽  
Running Wheel ◽  
Fundamental Information ◽  
Weight Support ◽  
In Vivo Testing ◽  
Tangential Forces ◽  
Force Data

Biomechanical data provide fundamental information about changes in musculoskeletal function during development, adaptation, and disease. To facilitate the study of mouse locomotor biomechanics, we modified a standard mouse running wheel to include a force-sensitive rung capable of measuring the normal and tangential forces applied by individual paws. Force data were collected throughout the night using an automated threshold trigger algorithm that synchronized force data with wheel-angle data and a high-speed infrared video file. During the first night of wheel running, mice reached consistent running speeds within the first 40 force events, indicating a rapid habituation to wheel running, given that mice generated >2,000 force-event files/night. Average running speeds and peak normal and tangential forces were consistent throughout the first four nights of running, indicating that one night of running is sufficient to characterize the locomotor biomechanics of healthy mice. Twelve weeks of wheel running significantly increased spontaneous wheel-running speeds (16 vs. 37 m/min), lowered duty factors (ratio of foot-ground contact time to stride time; 0.71 vs. 0.58), and raised hindlimb peak normal forces (93 vs. 115% body wt) compared with inexperienced mice. Peak normal hindlimb-force magnitudes were the primary force component, which were nearly tenfold greater than peak tangential forces. Peak normal hindlimb forces exceed the vertical forces generated during overground running (50-60% body wt), suggesting that wheel running shifts weight support toward the hindlimbs. This force-instrumented running-wheel system provides a comprehensive, noninvasive screening method for monitoring gait biomechanics in mice during spontaneous locomotion.

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

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.

scholarly journals A Study on the Influence of Tire Speed and Pressure on Measurement Parameters Obtained from High-Speed Tire Uniformity Testing

Vehicles ◽  
2020 ◽  
Vol 2 (3) ◽  
pp. 559-573
Author(s):  
Meng Du ◽  
Pengfei Sun ◽  
Shuiting Zhou ◽  
Hongwu Huang ◽  
Jie Zhu
Keyword(s):  
High Speed ◽  
Tangential Force ◽  
Testing Machine ◽  
Lateral Force ◽  
Radial Force ◽  
Signal Acquisition ◽  
Test Machine ◽  
Tire Pressure ◽  
Force Fluctuation ◽  
Uniformity Test

In order to improve the test conditions of the tire uniformity test and the effect of the speed and tire pressure on the uniformity parameters, the uniformity test of the tire under different speeds and tire pressure was carried out by a high-speed uniformity test machine, and the experimental data were analyzed and fitted by the regression analysis method. This paper introduces the definition of uniformity and the uniformity parameters of automotive tires; the working principle of a high-speed uniformity testing machine is briefly described, a mathematical model of the uniformity testing machine is established, and the signal acquisition process of the tire uniformity parameters and the calculation method of the uniformity parameters are described. The test result indicates: As the speed increases, the radial force fluctuation, lateral force fluctuation, tangential force fluctuation, and turning torque fluctuation of the tire increase, and the positive torque fluctuation first increases and then decreases; with the increase of tire pressure, the radial force fluctuation and the tangential force fluctuation of the tire increase, and the lateral force fluctuation, the turning torque fluctuation, and the returning moment fluctuation are all reduced. Compared to the low speed uniformity test, the high speed uniformity test can better reflect the uniformity of the tire, reducing the speed of the vehicle can reduce the radial runout and lateral sway of the tire; increasing the tire pressure can reduce the left and right swing of the vehicle.

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