1
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Cherif M, Brose U, Hirt MR, Ryser R, Silve V, Albert G, Arnott R, Berti E, Cirtwill A, Dyer A, Gauzens B, Gupta A, Ho HC, Portalier SMJ, Wain D, Wootton K. The environment to the rescue: can physics help predict predator-prey interactions? Biol Rev Camb Philos Soc 2024. [PMID: 38855988 DOI: 10.1111/brv.13105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 05/17/2024] [Accepted: 05/24/2024] [Indexed: 06/11/2024]
Abstract
Understanding the factors that determine the occurrence and strength of ecological interactions under specific abiotic and biotic conditions is fundamental since many aspects of ecological community stability and ecosystem functioning depend on patterns of interactions among species. Current approaches to mapping food webs are mostly based on traits, expert knowledge, experiments, and/or statistical inference. However, they do not offer clear mechanisms explaining how trophic interactions are affected by the interplay between organism characteristics and aspects of the physical environment, such as temperature, light intensity or viscosity. Hence, they cannot yet predict accurately how local food webs will respond to anthropogenic pressures, notably to climate change and species invasions. Herein, we propose a framework that synthesises recent developments in food-web theory, integrating body size and metabolism with the physical properties of ecosystems. We advocate for combination of the movement paradigm with a modular definition of the predation sequence, because movement is central to predator-prey interactions, and a generic, modular model is needed to describe all the possible variation in predator-prey interactions. Pending sufficient empirical and theoretical knowledge, our framework will help predict the food-web impacts of well-studied physical factors, such as temperature and oxygen availability, as well as less commonly considered variables such as wind, turbidity or electrical conductivity. An improved predictive capability will facilitate a better understanding of ecosystem responses to a changing world.
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Affiliation(s)
- Mehdi Cherif
- Aquatic Ecosystems and Global Change Research Unit, National Research Institute for Agriculture Food and the Environment, 50 avenue de Verdun, Cestas Cedex, 33612, France
| | - Ulrich Brose
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Puschstrasse 4, Leipzig, 04103, Germany
- Institute of Biodiversity, Friedrich Schiller University Jena, Dornburger Straße 159, Jena, 07743, Germany
| | - Myriam R Hirt
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Puschstrasse 4, Leipzig, 04103, Germany
- Institute of Biodiversity, Friedrich Schiller University Jena, Dornburger Straße 159, Jena, 07743, Germany
| | - Remo Ryser
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Puschstrasse 4, Leipzig, 04103, Germany
- Institute of Biodiversity, Friedrich Schiller University Jena, Dornburger Straße 159, Jena, 07743, Germany
| | - Violette Silve
- Aquatic Ecosystems and Global Change Research Unit, National Research Institute for Agriculture Food and the Environment, 50 avenue de Verdun, Cestas Cedex, 33612, France
| | - Georg Albert
- Department of Forest Nature Conservation, Georg-August-Universität, Büsgenweg 3, Göttingen, 37077, Germany
| | - Russell Arnott
- Sainsbury Laboratory, University of Cambridge, 47 Bateman Street, Cambridge, Cambridgeshire, CB2 1LR, UK
| | - Emilio Berti
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Puschstrasse 4, Leipzig, 04103, Germany
- Institute of Biodiversity, Friedrich Schiller University Jena, Dornburger Straße 159, Jena, 07743, Germany
| | - Alyssa Cirtwill
- Spatial Foodweb Ecology Group, Research Centre for Ecological Change (REC), Faculty of Biological and Environmental Sciences, University of Helsinki, P.O. Box 4 (Yliopistonkatu 3), Helsinki, 00014, Finland
| | - Alexander Dyer
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Puschstrasse 4, Leipzig, 04103, Germany
- Institute of Biodiversity, Friedrich Schiller University Jena, Dornburger Straße 159, Jena, 07743, Germany
| | - Benoit Gauzens
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Puschstrasse 4, Leipzig, 04103, Germany
- Institute of Biodiversity, Friedrich Schiller University Jena, Dornburger Straße 159, Jena, 07743, Germany
| | - Anhubav Gupta
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, Zürich, 8057, Switzerland
| | - Hsi-Cheng Ho
- Institute of Ecology and Evolutionary Biology, National Taiwan University, No. 1, Sec. 4, Roosevelt Rd, Taipei, 106, Taiwan
| | - Sébastien M J Portalier
- Department of Mathematics and Statistics, University of Ottawa, STEM Complex, room 342, 150 Louis-Pasteur Pvt, Ottawa, Ontario, K1N 6N5, Canada
| | - Danielle Wain
- 7 Lakes Alliance, Belgrade Lakes, 137 Main St, Belgrade Lakes, ME, 04918, USA
| | - Kate Wootton
- School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch, 8140, New Zealand
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2
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Skandalis DA, Baliga VB, Goller B, Altshuler DL. The spatiotemporal richness of hummingbird wing deformations. J Exp Biol 2024; 227:jeb246223. [PMID: 38680114 PMCID: PMC11166462 DOI: 10.1242/jeb.246223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 04/17/2024] [Indexed: 05/01/2024]
Abstract
Animals exhibit an abundant diversity of forms, and this diversity is even more evident when considering animals that can change shape on demand. The evolution of flexibility contributes to aspects of performance from propulsive efficiency to environmental navigation. It is, however, challenging to quantify and compare body parts that, by their nature, dynamically vary in shape over many time scales. Commonly, body configurations are tracked by labelled markers and quantified parametrically through conventional measures of size and shape (descriptor approach) or non-parametrically through data-driven analyses that broadly capture spatiotemporal deformation patterns (shape variable approach). We developed a weightless marker tracking technique and combined these analytic approaches to study wing morphological flexibility in hoverfeeding Anna's hummingbirds (Calypte anna). Four shape variables explained >95% of typical stroke cycle wing shape variation and were broadly correlated with specific conventional descriptors such as wing twist and area. Moreover, shape variables decomposed wing deformations into pairs of in-plane and out-of-plane components at integer multiples of the stroke frequency. This property allowed us to identify spatiotemporal deformation profiles characteristic of hoverfeeding with experimentally imposed kinematic constraints, including through shape variables explaining <10% of typical shape variation. Hoverfeeding in front of a visual barrier restricted stroke amplitude and elicited increased stroke frequencies together with in-plane and out-of-plane deformations throughout the stroke cycle. Lifting submaximal loads increased stroke amplitudes at similar stroke frequencies together with prominent in-plane deformations during the upstroke and pronation. Our study highlights how spatially and temporally distinct changes in wing shape can contribute to agile fluidic locomotion.
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Affiliation(s)
- Dimitri A. Skandalis
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada, V6T 1Z4
| | - Vikram B. Baliga
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada, V6T 1Z4
| | - Benjamin Goller
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada, V6T 1Z4
- College of Agriculture Data Services, Purdue University, West Lafayette, IN 47907-2053, USA
| | - Douglas L. Altshuler
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada, V6T 1Z4
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3
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Goyal P, van Leeuwen JL, Muijres FT. Bumblebees compensate for the adverse effects of sidewind during visually guided landings. J Exp Biol 2024; 227:jeb245432. [PMID: 38506223 PMCID: PMC11112349 DOI: 10.1242/jeb.245432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Accepted: 02/26/2024] [Indexed: 03/21/2024]
Abstract
Flying animals often encounter winds during visually guided landings. However, how winds affect their flight control strategy during landing is unknown. Here, we investigated how sidewind affects the landing performance and sensorimotor control of foraging bumblebees (Bombus terrestris). We trained bumblebees to forage in a wind tunnel, and used high-speed stereoscopic videography to record 19,421 landing maneuvers in six sidewind speeds (0 to 3.4 m s-1), which correspond to winds encountered in nature. Bumblebees landed less often in higher windspeeds, but the landing durations from free flight were not increased by wind. By testing how bumblebees adjusted their landing control to compensate for adverse effects of sidewind on landing, we showed that the landing strategy in sidewind resembled that in still air, but with important adaptations. Bumblebees landing in a sidewind tended to drift downwind, which they controlled for by performing more hover maneuvers. Surprisingly, the increased hover prevalence did not increase the duration of free-flight landing maneuvers, as these bumblebees flew faster towards the landing platform outside the hover phases. Hence, by alternating these two flight modes along their flight path, free-flying bumblebees negated the adverse effects of high windspeeds on landing duration. Using control theory, we hypothesize that bumblebees achieve this by integrating a combination of direct aerodynamic feedback and a wind-mediated mechanosensory feedback control, with their vision-based sensorimotor control loop. The revealed landing strategy may be commonly used by insects landing in windy conditions, and may inspire the development of landing control strategies onboard autonomously flying robots.
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Affiliation(s)
- Pulkit Goyal
- Experimental Zoology Group, Wageningen University and Research, 6708 WD Wageningen, The Netherlands
| | - Johan L. van Leeuwen
- Experimental Zoology Group, Wageningen University and Research, 6708 WD Wageningen, The Netherlands
| | - Florian T. Muijres
- Experimental Zoology Group, Wageningen University and Research, 6708 WD Wageningen, The Netherlands
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4
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Lempidakis E, Ross AN, Quetting M, Garde B, Wikelski M, Shepard ELC. Estimating fine-scale changes in turbulence using the movements of a flapping flier. J R Soc Interface 2022; 19:20220577. [PMID: 36349445 PMCID: PMC9653225 DOI: 10.1098/rsif.2022.0577] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
All animals that operate within the atmospheric boundary layer need to respond to aerial turbulence. Yet little is known about how flying animals do this because evaluating turbulence at fine scales (tens to approx. 300 m) is exceedingly difficult. Recently, data from animal-borne sensors have been used to assess wind and updraft strength, providing a new possibility for sensing the physical environment. We tested whether highly resolved changes in altitude and body acceleration measured onboard solo-flying pigeons (as model flapping fliers) can be used as qualitative proxies for turbulence. A range of pressure and acceleration proxies performed well when tested against independent turbulence measurements from a tri-axial anemometer mounted onboard an ultralight flying the same route, with stronger turbulence causing increasing vertical displacement. The best proxy for turbulence also varied with estimates of both convective velocity and wind shear. The approximately linear relationship between most proxies and turbulence levels suggests this approach should be widely applicable, providing insight into how turbulence changes in space and time. Furthermore, pigeons were able to fly in levels of turbulence that were unsafe for the ultralight, paving the way for the study of how freestream turbulence affects the costs and kinematics of animal flight.
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Affiliation(s)
| | - Andrew N. Ross
- School of Earth and Environment, University of Leeds, Leeds, UK
| | | | - Baptiste Garde
- Department of Biosciences, Swansea University, Singleton Park, Swansea, UK
| | - Martin Wikelski
- Max Planck Institute of Animal Behavior, Radolfzell, Germany
- Centre for the Advanced Study of Collective Behaviour, University of Konstanz, Konstanz, Germany
| | - Emily L. C. Shepard
- Department of Biosciences, Swansea University, Singleton Park, Swansea, UK
- Max Planck Institute of Animal Behavior, Radolfzell, Germany
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5
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Penn M, Yi G, Watkins S, Martinez Groves-Raines M, Windsor SP, Mohamed A. A method for continuous study of soaring and windhovering birds. Sci Rep 2022; 12:7038. [PMID: 35487925 PMCID: PMC9054774 DOI: 10.1038/s41598-022-10359-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Accepted: 03/14/2022] [Indexed: 11/09/2022] Open
Abstract
Avian flight continues to inspire aircraft designers. Reducing the scale of autonomous aircraft to that of birds and large insects has resulted in new control challenges when attempting to hold steady flight in turbulent atmospheric wind. Some birds, however, are capable of remarkably stable hovering flight in the same conditions. This work describes the development of a wind tunnel configuration that facilitates the study of flapless windhovering (hanging) and soaring bird flight in wind conditions replicating those in nature. Updrafts were generated by flow over replica "hills" and turbulence was introduced through upstream grids, which had already been developed to replicate atmospheric turbulence in prior studies. Successful flight tests with windhovering nankeen kestrels (Falco cenchroides) were conducted, verifying that the facility can support soaring and wind hovering bird flight. The wind tunnel allows the flow characteristics to be carefully controlled and measured, providing great advantages over outdoor flight tests. Also, existing wind tunnels may be readily configured using this method, providing a simpler alternative to the development of dedicated bird flight wind tunnels such as tilting wind tunnels, and the large test section allows for the replication of orographic soaring. This methodology holds promise for future testing investigating the flight behaviour and control responses employed by soaring and windhovering birds.
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Affiliation(s)
| | - George Yi
- RMIT University, Melbourne, Australia
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6
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Lempidakis E, Ross AN, Börger L, Shepard ELC. Airflow modelling predicts seabird breeding habitat across islands. ECOGRAPHY 2022; 2022:05733. [PMID: 34987352 PMCID: PMC7612159 DOI: 10.1111/ecog.05733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Accepted: 09/30/2021] [Indexed: 06/14/2023]
Abstract
Wind is fundamentally related to shelter and flight performance: two factors that are critical for birds at their nest sites. Despite this, airflows have never been fully integrated into models of breeding habitat selection, even for well-studied seabirds. Here, we use computational fluid dynamics to provide the first assessment of whether flow characteristics (including wind speed and turbulence) predict the distribution of seabird colonies, taking common guillemots Uria aalge breeding on Skomer Island as our study system. This demonstrates that occupancy is driven by the need to shelter from both wind and rain/wave action, rather than airflow characteristics alone. Models of airflows and cliff orientation both performed well in predicting high-quality habitat in our study site, identifying 80% of colonies and 93% of avoided sites, as well as 73% of the largest colonies on a neighbouring island. This suggests generality in the mechanisms driving breeding distributions and provides an approach for identifying habitat for seabird reintroductions considering current and projected wind speeds and directions.
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Affiliation(s)
| | - Andrew N Ross
- School of Earth and Environment, Univ. of Leeds, Leeds, UK
| | - Luca Börger
- Dept of Biosciences, Swansea Univ., Swansea, UK; Centre for Biomathematics, College of Science, Swansea Univ., Swansea, UK
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7
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Abstract
Turbulent winds and gusts fluctuate on a wide range of timescales from milliseconds to minutes and longer, a range that overlaps the timescales of avian flight behavior, yet the importance of turbulence to avian behavior is unclear. By combining wind speed data with the measured accelerations of a golden eagle (Aquila chrysaetos) flying in the wild, we find evidence in favor of a linear relationship between the eagle's accelerations and atmospheric turbulence for timescales between about 1/2 and 10 s. These timescales are comparable to those of typical eagle behaviors, corresponding to between about 1 and 25 wingbeats, and to those of turbulent gusts both larger than the eagle's wingspan and smaller than large-scale atmospheric phenomena such as convection cells. The eagle's accelerations exhibit power spectra and intermittent activity characteristic of turbulence and increase in proportion to the turbulence intensity. Intermittency results in accelerations that are occasionally several times stronger than gravity, which the eagle works against to stay aloft. These imprints of turbulence on the bird's movements need to be further explored to understand the energetics of birds and other volant life-forms, to improve our own methods of flying through ceaselessly turbulent environments, and to engage airborne wildlife as distributed probes of the changing conditions in the atmosphere.
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8
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Zenzal TJ, Ward MP, Diehl RH, Buler JJ, Smolinsky J, Deppe JL, Bolus RT, Celis‐Murillo A, Moore FR. Retreat, detour or advance? Understanding the movements of birds confronting the Gulf of Mexico. OIKOS 2021. [DOI: 10.1111/oik.07834] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Theodore J. Zenzal
- U.S. Geological Survey, Wetland and Aquatic Research Center Lafayette LA USA
- School of Biological, Environmental, and Earth Sciences, Univ. of Southern Mississippi Hattiesburg MS USA
| | - Michael P. Ward
- Dept of Natural Resources and Environmental Sciences, Univ. of Illinois Urbana IL USA
| | - Robert H. Diehl
- U.S. Geological Survey, Northern Rocky Mountain Science Center Bozeman MT USA
| | - Jeffrey J. Buler
- Dept of Entomology and Wildlife Ecology, Univ. of Delaware Newark DE USA
| | - Jaclyn Smolinsky
- Dept of Entomology and Wildlife Ecology, Univ. of Delaware Newark DE USA
- Cherokee Nation System Solutions, contracted to the US Geol. Surv., Wetland and Aguatic Res. Center Lafayette LA USA
| | | | | | | | - Frank R. Moore
- School of Biological, Environmental, and Earth Sciences, Univ. of Southern Mississippi Hattiesburg MS USA
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9
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Doussot C, Bertrand OJN, Egelhaaf M. The Critical Role of Head Movements for Spatial Representation During Bumblebees Learning Flight. Front Behav Neurosci 2021; 14:606590. [PMID: 33542681 PMCID: PMC7852487 DOI: 10.3389/fnbeh.2020.606590] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Accepted: 11/23/2020] [Indexed: 11/20/2022] Open
Abstract
Bumblebees perform complex flight maneuvers around the barely visible entrance of their nest upon their first departures. During these flights bees learn visual information about the surroundings, possibly including its spatial layout. They rely on this information to return home. Depth information can be derived from the apparent motion of the scenery on the bees' retina. This motion is shaped by the animal's flight and orientation: Bees employ a saccadic flight and gaze strategy, where rapid turns of the head (saccades) alternate with flight segments of apparently constant gaze direction (intersaccades). When during intersaccades the gaze direction is kept relatively constant, the apparent motion contains information about the distance of the animal to environmental objects, and thus, in an egocentric reference frame. Alternatively, when the gaze direction rotates around a fixed point in space, the animal perceives the depth structure relative to this pivot point, i.e., in an allocentric reference frame. If the pivot point is at the nest-hole, the information is nest-centric. Here, we investigate in which reference frames bumblebees perceive depth information during their learning flights. By precisely tracking the head orientation, we found that half of the time, the head appears to pivot actively. However, only few of the corresponding pivot points are close to the nest entrance. Our results indicate that bumblebees perceive visual information in several reference frames when they learn about the surroundings of a behaviorally relevant location.
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Affiliation(s)
- Charlotte Doussot
- Department of Neurobiology, University of Bielefeld, Bielefeld, Germany
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10
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Abstract
Sensing from a moving platform is challenging for both man-made machines and animals. Animals' heads jitter during movement, so if the sensors they carry are not stabilized, any spatial estimation might be biased. Flying animals, like bats, seriously suffer from this problem because flapping flight induces rapid changes in acceleration which moves the body up and down. For echolocating bats, the problem is crucial. Because they emit a sound to sense the world, an unstable head means sound energy pointed in the wrong direction. It is unknown how bats mitigate this problem. By tracking the head and body of flying fruit bats, we show that they stabilize their heads, accurately maintaining a fixed acoustic-gaze relative to a target. Bats can solve the stabilization task even in complete darkness using only echo-based information. Moreover, the bats point their echolocation beam below the target and not towards it, a strategy that should result in better estimations of target elevation.
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Affiliation(s)
- O Eitan
- School of Zoology, Faculty of Life Sciences, Tel Aviv University, Tel Aviv 6997801, Israel
| | - G Kosa
- Intelligent Medical Micro/Nano Systems Group, University Hospital of Basel, Basel, Switzerland
| | - Y Yovel
- School of Zoology, Faculty of Life Sciences, Tel Aviv University, Tel Aviv 6997801, Israel.,Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 6997801, Israel.,School of Mechanical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv 6997801, Israel
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11
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Longitudinal Modeling and Control of Tailed Flapping-Wings Micro Air Vehicles near Hovering. JOURNAL OF ROBOTICS 2019. [DOI: 10.1155/2019/9341012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Compared with the tailless flapping wing micro air vehicle (FMAV), the tailed FMAV has a simpler structure and is easier to control. However, although biplane FMAVs with tails have been used for flight control in practice for a long time, a theoretical model of the tailed FMAV has not previously been established. In this paper, we report modeling of the longitudinal dynamics of a tailed biplane FMAV using the Newton‐Euler equations. In this study, the vehicle was trimmed and linearized near its hovering equilibrium, assuming small disturbances. Then the stability of the hovering FMAV was analyzed with a modal analysis method. A state feedback controller was synthesized to stabilize the disturbance. Finally, we investigated the flight control of the tailed biplane FMAV with different control signals. Our results show that the natural‐motion mode determines the oscillation divergence characteristics of the tailed FMAV, a mode that can be suppressed with the state feedback controller by real‐time modulation of the tail. The tail can also be used to achieve different flight modes with different control‐signal functions. The tailed FMAV cruises in a line when the tail is controlled with a step function and spirals in an elliptical trajectory in the longitudinal plane when the tail is controlled by a sinusoidal function. Our longitudinal‐ dynamics model provides an analytical basis for further dynamic analyses of the tailed FMAV, as well as the corresponding controller synthesis. Moreover, the proposed attitude stabilization and flight control schemes for the vehicle near hovering provide a basis for developing practical uses of the tailed FMAV.
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12
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Durston NE, Wan X, Liu JG, Windsor SP. Avian surface reconstruction in free flight with application to flight stability analysis of a barn owl and peregrine falcon. ACTA ACUST UNITED AC 2019; 222:222/9/jeb185488. [PMID: 31068445 DOI: 10.1242/jeb.185488] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Accepted: 03/21/2019] [Indexed: 11/20/2022]
Abstract
Birds primarily create and control the forces necessary for flight through changing the shape and orientation of their wings and tail. Their wing geometry is characterised by complex variation in parameters such as camber, twist, sweep and dihedral. To characterise this complexity, a multi-view stereo-photogrammetry setup was developed for accurately measuring surface geometry in high resolution during free flight. The natural patterning of the birds was used as the basis for phase correlation-based image matching, allowing indoor or outdoor use while being non-intrusive for the birds. The accuracy of the method was quantified and shown to be sufficient for characterising the geometric parameters of interest, but with a reduction in accuracy close to the wing edge and in some localised regions. To demonstrate the method's utility, surface reconstructions are presented for a barn owl (Tyto alba) and peregrine falcon (Falco peregrinus) during three instants of gliding flight per bird. The barn owl flew with a consistent geometry, with positive wing camber and longitudinal anhedral. Based on flight dynamics theory, this suggests it was longitudinally statically unstable during these flights. The peregrine falcon flew with a consistent glide angle, but at a range of air speeds with varying geometry. Unlike the barn owl, its glide configuration did not provide a clear indication of longitudinal static stability/instability. Aspects of the geometries adopted by both birds appeared to be related to control corrections and this method would be well suited for future investigations in this area, as well as for other quantitative studies into avian flight dynamics.
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Affiliation(s)
- Nicholas E Durston
- Department of Aerospace Engineering, University of Bristol, Queen's Building, University Walk, Bristol BS8 1TR, UK
| | - Xue Wan
- Department of Earth Science and Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, UK.,Key Laboratory of Space Utilization, Technology and Engineering Center for Space Utilization, Chinese Academy of Sciences, Beijing, 100094, China
| | - Jian G Liu
- Department of Earth Science and Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
| | - Shane P Windsor
- Department of Aerospace Engineering, University of Bristol, Queen's Building, University Walk, Bristol BS8 1TR, UK
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13
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Badger MA, Wang H, Dudley R. Avoiding topsy-turvy: how Anna's hummingbirds ( Calypte anna) fly through upward gusts. ACTA ACUST UNITED AC 2019; 222:222/3/jeb176263. [PMID: 30718291 DOI: 10.1242/jeb.176263] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2017] [Accepted: 12/05/2018] [Indexed: 11/20/2022]
Abstract
Flying organisms frequently confront the challenge of maintaining stability when moving within highly dynamic airflows near the Earth's surface. Either aerodynamic or inertial forces generated by appendages and other structures, such as the tail, may be used to offset aerial perturbations, but these responses have not been well characterized. To better understand how hummingbirds modify wing and tail motions in response to individual gusts, we filmed Anna's hummingbirds as they negotiated an upward jet of fast-moving air. Birds exhibited large variation in wing elevation, tail pitch and tail fan angles among transits as they repeatedly negotiated the same gust, and often exhibited a dramatic decrease in body angle (29±6 deg) post-transit. After extracting three-dimensional kinematic features, we identified a spectrum of control strategies for gust transit, with one extreme involving continuous flapping, no tail fanning and little disruption to body posture (23±3 deg downward pitch), and the other extreme characterized by dorsal wing pausing, tail fanning and greater downward body pitch (38±4 deg). The use of a deflectable tail on a glider model transiting the same gust resulted in enhanced stability and can easily be implemented in the design of aerial robots.
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Affiliation(s)
- Marc A Badger
- Department of Integrative Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Hao Wang
- College of Astronautics, Nanjing University of Aeronautics & Astronautics, 29 Yudao St., 210016 Nanjing, China
| | - Robert Dudley
- Department of Integrative Biology, University of California, Berkeley, Berkeley, CA 94720, USA
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14
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Boerma DB, Breuer KS, Treskatis TL, Swartz SM. Wings as inertial appendages: how bats recover from aerial stumbles. J Exp Biol 2019; 222:jeb.204255. [DOI: 10.1242/jeb.204255] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Accepted: 09/16/2019] [Indexed: 11/20/2022]
Abstract
For many animals, movement through complex natural environments necessitates the evolution of mechanisms that enable recovery from unexpected perturbations. Knowledge of how flying animals contend with disruptive forces is limited, however, and is nearly nonexistent for bats, the only mammals capable of powered flight. We investigated perturbation recovery in Carollia perspicillata by administering a well-defined jet of compressed air, equal to 2.5 times bodyweight, which induced two types of disturbances, termed aerial stumbles: pitch-inducing body perturbations and roll-inducing wing perturbations. In both cases, bats responded primarily by adjusting extension of wing joints, and recovered pre-disturbance body orientation and left-right symmetry of wing motions over the course of only one wingbeat cycle. Bats recovered from body perturbations by symmetrically extending their wings cranially and dorsally during upstroke, and from wing perturbations by asymmetrically extending their wings throughout the recovery wingbeat. We used a simplified dynamical model to test the hypothesis that wing extension asymmetry during recovery from roll-inducing perturbations can generate inertial torques that alone are sufficient to produce the observed body reorientation. Results supported the hypothesis, and also suggested that subsequent restoration of symmetrical wing extension helped decelerate recovery rotation via passive aerodynamic mechanisms. During recovery, humeral elevation/depression remained largely unchanged while bats adjusted wing extension at the elbow and wrist, suggesting a proximo-distal gradient in the neuromechanical control of the wing.
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Affiliation(s)
- David B. Boerma
- Department of Ecology and Evolutionary Biology, Brown University, Providence, RI 02912, USA
| | - Kenneth S. Breuer
- School of Engineering, Brown University, Providence, RI 02912, USA
- Department of Ecology and Evolutionary Biology, Brown University, Providence, RI 02912, USA
| | - Tim L. Treskatis
- Westphalian University of Applied Sciences, 45897 Gelsenkirchen, Germany
| | - Sharon M. Swartz
- Department of Ecology and Evolutionary Biology, Brown University, Providence, RI 02912, USA
- School of Engineering, Brown University, Providence, RI 02912, USA
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15
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Matthews M, Sponberg S. Hawkmoth flight in the unsteady wakes of flowers. ACTA ACUST UNITED AC 2018; 221:jeb.179259. [PMID: 30291159 DOI: 10.1242/jeb.179259] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Accepted: 09/26/2018] [Indexed: 02/06/2023]
Abstract
Flying animals maneuver and hover through environments where wind gusts and flower wakes produce unsteady flow. Although both flight maneuvers and aerodynamic mechanisms have been studied independently, little is known about how these interact in an environment where flow is already unsteady. Moths forage from flowers by hovering in the flower's wake. We investigated hawkmoths tracking a 3D-printed robotic flower in a wind tunnel. We visualized the flow in the wake and around the wings and compared tracking performance with previous experiments in a still-air flight chamber. As in still air, moths flying in the flower wake exhibit near-perfect tracking at the low frequencies at which natural flowers move. However, tracking in the flower wake results in a larger overshoot between 2 and 5 Hz. System identification of flower tracking reveals that moths also display reduced-order dynamics in wind compared with still air. Smoke visualization of the flower wake shows that the dominant vortex shedding corresponds to the same frequency band as the increased overshoot. Despite these large effects on tracking dynamics in wind, the leading edge vortex (LEV) remains bound to the wing throughout the wingstroke and does not burst. The LEV also maintains the same qualitative structure seen in steady air. Persistence of a stable LEV during decreased flower tracking demonstrates the interplay between hovering and maneuvering.
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Affiliation(s)
- Megan Matthews
- School of Physics, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Simon Sponberg
- School of Physics, Georgia Institute of Technology, Atlanta, GA 30332, USA.,School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA
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16
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Jakobi T, Kolomenskiy D, Ikeda T, Watkins S, Fisher A, Liu H, Ravi S. Bees with attitude: the effects of directed gusts on flight trajectories. Biol Open 2018; 7:bio.034074. [PMID: 30135080 PMCID: PMC6215418 DOI: 10.1242/bio.034074] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Flight is a complicated task at the centimetre scale particularly due to unsteady air fluctuations which are ubiquitous in outdoor flight environments. Flying organisms deal with these difficulties using active and passive control mechanisms to steer their body motion. Body attitudes of flapping organisms are linked with their resultant flight trajectories and performance, yet little is understood about how isolated unsteady aerodynamic phenomena affect the interlaced dynamics of such systems. In this study, we examined freely flying bumblebees subject to a single isolated gust to emulate aerodynamic disturbances encountered in nature. Bumblebees are expert commanders of the aerial domain as they persistently forage within complex terrain elements. By tracking the three-dimensional dynamics of bees flying through gusts, we determined the sequences of motion that permit flight in three disturbance conditions: sideward, upward and downward gusts. Bees executed a series of passive impulsive maneuvers followed by active recovery maneuvers. Impulsive motion was unique in each gust direction, maintaining control by passive manipulation of the body. Bees pitched up and slowed down at the beginning of recovery in every disturbance, followed by corrective maneuvers which brought body attitudes back to their original state. Bees were displaced the most by the sideward gust, displaying large lateral translations and roll deviations. Upward gusts were easier for bees to fly through, causing only minor flight changes and minimal recovery times. Downward gusts severely impaired the control response of bees, inflicting strong adverse forces which sharply upset trajectories. Bees used a variety of control strategies when flying in each disturbance, offering new insights into insect-scale flapping flight and bio-inspired robotic systems.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Timothy Jakobi
- School of Aerospace Mechanical and Manufacturing Engineering, RMIT University, Melbourne, 3083, Australia
| | - Dmitry Kolomenskiy
- Japan Agency for Marine-Earth Science Technology (JAMSTEC), Yokohama-shi, 236-0001, Japan
| | - Teruaki Ikeda
- Graduate School of Engineering, Chiba University, Chiba-shi, 263-8522, Japan
| | - Simon Watkins
- School of Aerospace Mechanical and Manufacturing Engineering, RMIT University, Melbourne, 3083, Australia
| | - Alex Fisher
- School of Aerospace Mechanical and Manufacturing Engineering, RMIT University, Melbourne, 3083, Australia
| | - Hao Liu
- Graduate School of Engineering, Chiba University, Chiba-shi, 263-8522, Japan
| | - Sridhar Ravi
- School of Aerospace Mechanical and Manufacturing Engineering, RMIT University, Melbourne, 3083, Australia
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17
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Zenzal TJ, Moore FR, Diehl RH, Ward MP, Deppe JL. Migratory hummingbirds make their own rules: the decision to resume migration along a barrier. Anim Behav 2018. [DOI: 10.1016/j.anbehav.2018.01.019] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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18
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Liu H, Ravi S, Kolomenskiy D, Tanaka H. Biomechanics and biomimetics in insect-inspired flight systems. Philos Trans R Soc Lond B Biol Sci 2017; 371:rstb.2015.0390. [PMID: 27528780 PMCID: PMC4992714 DOI: 10.1098/rstb.2015.0390] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/19/2016] [Indexed: 11/12/2022] Open
Abstract
Insect- and bird-size drones-micro air vehicles (MAV) that can perform autonomous flight in natural and man-made environments are now an active and well-integrated research area. MAVs normally operate at a low speed in a Reynolds number regime of 10(4)-10(5) or lower, in which most flying animals of insects, birds and bats fly, and encounter unconventional challenges in generating sufficient aerodynamic forces to stay airborne and in controlling flight autonomy to achieve complex manoeuvres. Flying insects that power and control flight by flapping wings are capable of sophisticated aerodynamic force production and precise, agile manoeuvring, through an integrated system consisting of wings to generate aerodynamic force, muscles to move the wings and a control system to modulate power output from the muscles. In this article, we give a selective review on the state of the art of biomechanics in bioinspired flight systems in terms of flapping and flexible wing aerodynamics, flight dynamics and stability, passive and active mechanisms in stabilization and control, as well as flapping flight in unsteady environments. We further highlight recent advances in biomimetics of flapping-wing MAVs with a specific focus on insect-inspired wing design and fabrication, as well as sensing systems.This article is part of the themed issue 'Moving in a moving medium: new perspectives on flight'.
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Affiliation(s)
- Hao Liu
- Graduate School of Engineering, Chiba University, Chiba, Japan Shanghai-Jiao Tong University and Chiba University International Cooperative Research Centre (SJTU-CU ICRC), Shanghai, People's Republic of China
| | - Sridhar Ravi
- Graduate School of Engineering, Chiba University, Chiba, Japan School of Aerospace Mechanical and Manufacturing Engineering, RMIT University, Melbourne, Australia
| | | | - Hiroto Tanaka
- Graduate School of Science and Engineering, Tokyo Institute of Technology, Tokyo, Japan
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19
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Goller B, Segre PS, Middleton KM, Dickinson MH, Altshuler DL. Visual Sensory Signals Dominate Tactile Cues during Docked Feeding in Hummingbirds. Front Neurosci 2017; 11:622. [PMID: 29184479 PMCID: PMC5694540 DOI: 10.3389/fnins.2017.00622] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 10/25/2017] [Indexed: 11/13/2022] Open
Abstract
Animals living in and interacting with natural environments must monitor and respond to changing conditions and unpredictable situations. Using information from multiple sensory systems allows them to modify their behavior in response to their dynamic environment but also creates the challenge of integrating different, and potentially contradictory, sources of information for behavior control. Understanding how multiple information streams are integrated to produce flexible and reliable behavior is key to understanding how behavior is controlled in natural settings. Natural settings are rarely still, which challenges animals that require precise body position control, like hummingbirds, which hover while feeding from flowers. Tactile feedback, available only once the hummingbird is docked at the flower, could provide additional information to help maintain its position at the flower. To investigate the role of tactile information for hovering control during feeding, we first asked whether hummingbirds physically interact with a feeder once docked. We quantified physical interactions between docked hummingbirds and a feeder placed in front of a stationary background pattern. Force sensors on the feeder measured a complex time course of loading that reflects the wingbeat frequency and bill movement of feeding hummingbirds, and suggests that they sometimes push against the feeder with their bill. Next, we asked whether the measured tactile interactions were used by feeding hummingbirds to maintain position relative to the feeder. We created two experimental scenarios-one in which the feeder was stationary and the visual background moved and the other where the feeder moved laterally in front of a white background. When the visual background pattern moved, docked hummingbirds pushed significantly harder in the direction of horizontal visual motion. When the feeder moved, and the background was stationary, hummingbirds generated aerodynamic force in the opposite direction of the feeder motion. These results suggest that docked hummingbirds are using visual information about the environment to maintain body position and orientation, and not actively tracking the motion of the feeder. The absence of flower tracking behavior in hummingbirds contrasts with the behavior of hawkmoths, and provides evidence that they rely primarily on the visual background rather than flower-based cues while feeding.
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Affiliation(s)
- Benjamin Goller
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada
| | - Paolo S. Segre
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada
| | - Kevin M. Middleton
- Department of Pathology and Anatomical Sciences, University of Missouri, Columbia, MO, United States
| | - Michael H. Dickinson
- Bioengineering and Biology, California Institute of Technology, Pasadena, CA, United States
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20
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Quinn DB, van Halder Y, Lentink D. Adaptive control of turbulence intensity is accelerated by frugal flow sampling. J R Soc Interface 2017; 14:rsif.2017.0621. [PMID: 29118116 DOI: 10.1098/rsif.2017.0621] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Accepted: 10/17/2017] [Indexed: 11/12/2022] Open
Abstract
The aerodynamic performance of vehicles and animals, as well as the productivity of turbines and energy harvesters, depends on the turbulence intensity of the incoming flow. Previous studies have pointed at the potential benefits of active closed-loop turbulence control. However, it is unclear what the minimal sensory and algorithmic requirements are for realizing this control. Here we show that very low-bandwidth anemometers record sufficient information for an adaptive control algorithm to converge quickly. Our online Newton-Raphson algorithm tunes the turbulence in a recirculating wind tunnel by taking readings from an anemometer in the test section. After starting at 9% turbulence intensity, the algorithm converges on values ranging from 10% to 45% in less than 12 iterations within 1% accuracy. By down-sampling our measurements, we show that very-low-bandwidth anemometers record sufficient information for convergence. Furthermore, down-sampling accelerates convergence by smoothing gradients in turbulence intensity. Our results explain why low-bandwidth anemometers in engineering and mechanoreceptors in biology may be sufficient for adaptive control of turbulence intensity. Finally, our analysis suggests that, if certain turbulent eddy sizes are more important to control than others, frugal adaptive control schemes can be particularly computationally effective for improving performance.
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Affiliation(s)
- Daniel B Quinn
- Department of Mechanical Engineering, Stanford University, Stanford, CA 94305-3030, USA
| | - Yous van Halder
- Department of Mechanical Engineering, Stanford University, Stanford, CA 94305-3030, USA
| | - David Lentink
- Department of Mechanical Engineering, Stanford University, Stanford, CA 94305-3030, USA
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21
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Liu P, Cheng B. Limitations of rotational manoeuvrability in insects and hummingbirds: evaluating the effects of neuro-biomechanical delays and muscle mechanical power. J R Soc Interface 2017; 14:rsif.2017.0068. [PMID: 28679665 DOI: 10.1098/rsif.2017.0068] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2017] [Accepted: 06/05/2017] [Indexed: 11/12/2022] Open
Abstract
Flying animals ranging in size from fruit flies to hummingbirds are nimble fliers with remarkable rotational manoeuvrability. The degrees of manoeuvrability among these animals, however, are noticeably diverse and do not simply follow scaling rules of flight dynamics or muscle power capacity. As all manoeuvres emerge from the complex interactions of neural, physiological and biomechanical processes of an animal's flight control system, these processes give rise to multiple limiting factors that dictate the maximal manoeuvrability attainable by an animal. Here using functional models of an animal's flight control system, we investigate the effects of three such limiting factors, including neural and biomechanical (from limited flapping frequency) delays and muscle mechanical power, for two insect species and two hummingbird species, undergoing roll, pitch and yaw rotations. The results show that for animals with similar degree of manoeuvrability, for example, fruit flies and hummingbirds, the underlying limiting factors are different, as the manoeuvrability of fruit flies is only limited by neural delays and that of hummingbirds could be limited by all three factors. In addition, the manoeuvrability also appears to be the highest about the roll axis as it requires the least muscle mechanical power and can tolerate the largest neural delays.
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Affiliation(s)
- Pan Liu
- Department of Mechanical and Nuclear Engineering, Pennsylvania State University, University Park, PA 16802, USA
| | - Bo Cheng
- Department of Mechanical and Nuclear Engineering, Pennsylvania State University, University Park, PA 16802, USA
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22
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Crall JD, Chang JJ, Oppenheimer RL, Combes SA. Foraging in an unsteady world: bumblebee flight performance in field-realistic turbulence. Interface Focus 2017; 7:20160086. [PMID: 28163878 DOI: 10.1098/rsfs.2016.0086] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Natural environments are characterized by variable wind that can pose significant challenges for flying animals and robots. However, our understanding of the flow conditions that animals experience outdoors and how these impact flight performance remains limited. Here, we combine laboratory and field experiments to characterize wind conditions encountered by foraging bumblebees in outdoor environments and test the effects of these conditions on flight. We used radio-frequency tags to track foraging activity of uniquely identified bumblebee (Bombus impatiens) workers, while simultaneously recording local wind flows. Despite being subjected to a wide range of speeds and turbulence intensities, we find that bees do not avoid foraging in windy conditions. We then examined the impacts of turbulence on bumblebee flight in a wind tunnel. Rolling instabilities increased in turbulence, but only at higher wind speeds. Bees displayed higher mean wingbeat frequency and stroke amplitude in these conditions, as well as increased asymmetry in stroke amplitude-suggesting that bees employ an array of active responses to enable flight in turbulence, which may increase the energetic cost of flight. Our results provide the first direct evidence that moderate, environmentally relevant turbulence affects insect flight performance, and suggest that flying insects use diverse mechanisms to cope with these instabilities.
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Affiliation(s)
- J D Crall
- Department of Organismic and Evolutionary Biology , Harvard University , Cambridge, MA , USA
| | - J J Chang
- Department of Neuroscience , Columbia University , New York, NY , USA
| | - R L Oppenheimer
- Department of Biological Sciences , University of New Hampshire , Durham, NH , USA
| | - S A Combes
- Department of Neurobiology, Physiology, and Behavior , University of California, Davis , Davis, CA , USA
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23
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Fisher A, Ravi S, Watkins S, Watmuff J, Wang C, Liu H, Petersen P. The gust-mitigating potential of flapping wings. BIOINSPIRATION & BIOMIMETICS 2016; 11:046010. [PMID: 27481211 DOI: 10.1088/1748-3190/11/4/046010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Nature's flapping-wing flyers are adept at negotiating highly turbulent flows across a wide range of scales. This is in part due to their ability to quickly detect and counterract disturbances to their flight path, but may also be assisted by an inherent aerodynamic property of flapping wings. In this study, we subject a mechanical flapping wing to replicated atmospheric turbulence across a range of flapping frequencies and turbulence intensities. By means of flow visualization and surface pressure measurements, we determine the salient effects of large-scale freestream turbulence on the flow field, and on the phase-average and fluctuating components of pressure and lift. It is shown that at lower flapping frequencies, turbulence dominates the instantaneous flow field, and the random fluctuating component of lift contributes significantly to the total lift. At higher flapping frequencies, kinematic forcing begins to dominate and the flow field becomes more consistent from cycle to cycle. Turbulence still modulates the flapping-induced flow field, as evidenced in particular by a variation in the timing and extent of leading edge vortex formation during the early downstroke. The random fluctuating component of lift contributes less to the total lift at these frequencies, providing evidence that flapping wings do indeed provide some inherent gust mitigation.
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24
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Shyy W, Kang CK, Chirarattananon P, Ravi S, Liu H. Aerodynamics, sensing and control of insect-scale flapping-wing flight. Proc Math Phys Eng Sci 2016; 472:20150712. [PMID: 27118897 PMCID: PMC4841661 DOI: 10.1098/rspa.2015.0712] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Accepted: 01/04/2016] [Indexed: 11/12/2022] Open
Abstract
There are nearly a million known species of flying insects and 13 000 species of flying warm-blooded vertebrates, including mammals, birds and bats. While in flight, their wings not only move forward relative to the air, they also flap up and down, plunge and sweep, so that both lift and thrust can be generated and balanced, accommodate uncertain surrounding environment, with superior flight stability and dynamics with highly varied speeds and missions. As the size of a flyer is reduced, the wing-to-body mass ratio tends to decrease as well. Furthermore, these flyers use integrated system consisting of wings to generate aerodynamic forces, muscles to move the wings, and sensing and control systems to guide and manoeuvre. In this article, recent advances in insect-scale flapping-wing aerodynamics, flexible wing structures, unsteady flight environment, sensing, stability and control are reviewed with perspective offered. In particular, the special features of the low Reynolds number flyers associated with small sizes, thin and light structures, slow flight with comparable wind gust speeds, bioinspired fabrication of wing structures, neuron-based sensing and adaptive control are highlighted.
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Affiliation(s)
- Wei Shyy
- Department of Mechanical and Aerospace Engineering, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong
| | - Chang-kwon Kang
- Department of Mechanical and Aerospace Engineering, University of Alabama in Huntsville, Huntsville, AL, USA
| | - Pakpong Chirarattananon
- Department of Mechanical and Biomedical Engineering, City University of Hong Kong, Kowloon Tong, Hong Kong
| | - Sridhar Ravi
- Graduate School of Engineering, Chiba University, Chiba, Japan
- School of Aerospace, Mechanical and Manufacturing Engineering, RMIT University, Melbourne, Victoria, Australia
| | - Hao Liu
- School of Aerospace, Mechanical and Manufacturing Engineering, RMIT University, Melbourne, Victoria, Australia
- Shanghai-Jiao Tong University and Chiba, University International Cooperative Research Centre (SJTU-CU ICRC), Minhang, Shanghai, China
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25
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Engels T, Kolomenskiy D, Schneider K, Lehmann FO, Sesterhenn J. Bumblebee Flight in Heavy Turbulence. PHYSICAL REVIEW LETTERS 2016; 116:028103. [PMID: 26824570 DOI: 10.1103/physrevlett.116.028103] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Indexed: 06/05/2023]
Abstract
High-resolution numerical simulations of a tethered model bumblebee in forward flight are performed superimposing homogeneous isotropic turbulent fluctuations to the uniform inflow. Despite tremendous variation in turbulence intensity, between 17% and 99% with respect to the mean flow, we do not find significant changes in cycle-averaged aerodynamic forces, moments, or flight power when averaged over realizations, compared to laminar inflow conditions. The variance of aerodynamic measures, however, significantly increases with increasing turbulence intensity, which may explain flight instabilities observed in freely flying bees.
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Affiliation(s)
- T Engels
- M2P2-CNRS & Aix-Marseille Université, 38 rue Joliot-Curie, 13451 Marseille cedex 20 France
- ISTA, Technische Universität Berlin, Müller-Breslau-Strasse 12, 10623 Berlin, Germany
| | - D Kolomenskiy
- Graduate School of Engineering, Chiba University, 1-33 Yayoi-Cho, Inage-Ku, Chiba-Shi, Chiba 263-8522, Japan
| | - K Schneider
- M2P2-CNRS & Aix-Marseille Université, 38 rue Joliot-Curie, 13451 Marseille cedex 20 France
| | - F-O Lehmann
- Department of Animal Physiology, University of Rostock, Albert-Einstein-Strasse 3, 18059 Rostock, Germany
| | - J Sesterhenn
- ISTA, Technische Universität Berlin, Müller-Breslau-Strasse 12, 10623 Berlin, Germany
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26
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Mistick EA, Mountcastle AM, Combes SA. Wing flexibility improves bumblebee flight stability. J Exp Biol 2016; 219:3384-3390. [DOI: 10.1242/jeb.133157] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2015] [Accepted: 08/17/2016] [Indexed: 11/20/2022]
Abstract
Insect wings do not contain intrinsic musculature to change shape, but rather bend and twist passively during flight. Some insect wings feature flexible joints along their veins that contain patches of resilin, a rubber-like protein. Bumblebee wings exhibit a central resilin joint (1m-cu) that has previously been shown to improve vertical force production during hovering flight. In this study, we artificially stiffened bumblebee (Bombus impatiens) wings in vivo by applying a micro-splint to the 1m-cu joint, and measured the consequences for body stability during forward flight in both laminar and turbulent airflow. In laminar flow, bees with stiffened wings exhibited significantly higher mean rotation rates and standard deviation of orientation about the roll axis. Decreasing the wing’s flexibility significantly increased its projected surface area relative to the oncoming airflow, likely increasing the drag force it experienced during particular phases of the wingstroke. We hypothesize that higher drag forces on stiffened wings decrease body stability when the left and right wings encounter different flow conditions. Wing splinting also led to a small increase in body rotation rates in turbulent airflow, but this change was not statistically significant, possibly because bees with stiffened wings changed their flight behavior in turbulent flow. Overall, we find that wing flexibility improves flight stability in bumblebees, adding to the growing appreciation that wing flexibility is not merely an inevitable liability in flapping flight, but can enhance flight performance.
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Affiliation(s)
- Emily A. Mistick
- Harvard University, Department of Organismic and Evolutionary Biology, Concord Field Station, 100 Old Causeway Road, Bedford, MA 01730, USA
| | - Andrew M. Mountcastle
- Harvard University, Department of Organismic and Evolutionary Biology, Concord Field Station, 100 Old Causeway Road, Bedford, MA 01730, USA
| | - Stacey A. Combes
- University of California, Davis, Department of Neurobiology, Physiology, and Behavior, 1 Shields Avenue, Davis, CA 95616, USA
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