Flight Kinematics Research Articles

Mosquitoes integrate visual and acoustic cues to mediate conspecific interactions in swarms

Male mosquitoes form aerial aggregations, known as swarms, to attract females and maximize their chances of finding a mate. Within these swarms, individuals must be able to recognize potential mates and navigate the social environment to successfully intercept a mating partner. Prior research has almost exclusively focused on the role of acoustic cues in mediating the male mosquito's ability to recognize and pursue females. However, the role of other sensory modalities in this behavior has not been explored. Moreover, how males avoid collisions with one another in the swarm while pursuing females remains poorly understood. In this study, we combined free-flight and tethered-flight simulator experiments to demonstrate that swarming Anopheles coluzzii mosquitoes integrate visual and acoustic information to track conspecifics and avoid collisions. Our tethered experiments revealed that acoustic stimuli gated mosquito steering responses to visual objects simulating nearby mosquitoes, especially in males that exhibited a strong response toward visual objects in the presence of female flight tones. Additionally, we observed that visual cues alone could trigger changes in mosquitoes' wingbeat amplitude and frequency. These findings were corroborated by our free-flight experiments, which revealed that Anopheles coluzzii modulate their thrust-based flight responses to nearby conspecifics in a similar manner to tethered animals, potentially allowing for collision avoidance within swarms. Together, these results demonstrate that both males and females integrate multiple sensory inputs to mediate swarming behavior, and for males, the change in flight kinematics in response to multimodal cues might allow them to simultaneously track females while avoiding collisions.

A robotic platform for mimicking the flapping flight of bats

To understand how bats control their wing movements based on biosonar inputs, it is important to identify the key kinematic synergies that need to be replicated on a robotic prototype so its wingbeat patterns and aerodynamic capabilities matches its biological counterpart. Attempting to replicate the approximately 20 degrees of freedom in each bat wing is challenging since more mechanical degrees of freedom increase mass and reduce reliability. Our proposed approach, is based on recordings of the kinematics of maneuvering bats that are obtained from high-speed camera data. The first two synergistic actions to implemented in the robot were wing flapping and folding that work together to increase net lift generation. During straight flight, these synergies follow a fixed synchronized pattern allowing a single-actuator robot model to mimic key bat flight characteristics. By recording the robot prototype's flight kinematics with the same high-speed camera setup, we can compare the flight kinematics of bats and flapping-flight robots inspired by them, quantifying differences in complexity and performance. The goal is a bioinspired robotic platform enabling detailed study of bat flight biomechanics and control strategies. This will provide new biological insights and advance flapping-flight robot development by determining kinematic complexity required for bat-like performance.

Of bats and robots

Some bat species feature joint adaptations to their biosonar sensing and flight systems that allow them to navigate and hunt in dense vegetation. Understanding how biosonar sensing and flight are connected in these species poses a challenge: Kinematics recordings of bat-flight can document the system outputs, but due to various limitations, especially on processing, analysis of bat flight has been limited to minimal numbers of flights and hence has had difficulty to capture the natural variability in flight maneuvers. On the input side of the bats' flight-control system, it is necessary to understand the stimulus ensemble that guides flight in dense vegetation. Navigation in these cases must be based on clutter echoes, i.e., signals consisting of many unresolved components. Since the biosonar inputs into a bat are difficult to record without heavy interference with the animals' behaviors. Hence, biomimetic sonar robots can be used to collect stimuli from natural environments and their recreations. With their superior abilities to find patterns, deep-learning offer an opportunity to cut through the complexity of the input and output data of bat flight control and elucidate how clutter echoes are interfaced with the high-dimensional flight kinematics of bats to create the animals' exceptional maneuvering capabilities.

Numerical simulation of bending and length-varying flapping wing using discrete vortex method

The paper aims to perform numerical simulations of flapping flight using Discrete Vortex Method (DVM) scheme. The scheme is suitable for moderately low Reynolds number [Formula: see text] and computationally less expensive as the flow domain doesn’t need to be discretized at each time step. Flapping of a one-dimensional (1D) flexible filament in a two-dimensional (2D) inviscid flow is simulated. The effect of bending by varying the wing shape along the spanwise length on aerodynamic performance was studied. It is observed that compared to rigid wings, bending wings are found to be better in generating lift. The effect of various bending wing configurations ([Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text]) and different methods of imposing the bending ([Formula: see text], [Formula: see text] and [Formula: see text]) is studied. It was demonstrated that applying wing bending only during the downstroke phase ([Formula: see text]) is more effective than imposing bending throughout the flapping cycle ([Formula: see text]). Moreover, an effort is made to replicate the bending configuration observed in manta ray fish ([Formula: see text]) to investigate its impact on flow domain characteristics, lift, and thrust forces. Furthermore, the inclusion of a winglet is found to significantly enhance lift generation. In addition to the study of bending effects on aerodynamic performance, the study also seeks to emulate a unique aspect of bat flight kinematics, specifically the dynamic variation in wing span length during flapping. In a comparative analysis of two span length variation strategies, it is discerned that exclusively varying span length during the upstroke phase is the optimal approach for achieving increased lift generation. The study highlights the crucial role of wing bending and span length modulation in achieving elevated lift forces while simultaneously reducing drag. These findings are seen as holding significant promise for the design and optimization of Micro Air Vehicles (MAVs) utilizing flapping-based lift generation mechanisms, contributing substantially to the identification of optimal parameters for enhancing MAVs’ aerodynamic performance and operational efficiency.

Moderate mass loss enhances flight performance via alteration of flight kinematics and postures in a passerine bird.

Many birds experience fluctuations in body mass throughout the annual life cycle. The flight efficiency hypothesis posits that adaptive mass loss can enhance avian flight ability. However, whether birds can increase additional wing loading following mass loss and how birds adjust flight kinematics and postures remain largely unexplored. We investigated physiological changes in body condition in breeding female Eurasian tree sparrows (Passer montanus) through a dietary restriction experiment and determined the changes in flight kinematics and postures. Body mass decreased significantly, but the external maximum load and mass-corrected total load increased significantly after 3days of dietary restriction. After 6days of dietary restriction (DR6), hematocrit, pectoralis and hepatic fat content, take-off speed, theoretical maximum range speed and maximum power speed declined significantly. Notably, the load capacity and power margin remained unchanged relative to the control group. The wing stroke amplitude and relative downstroke duration were not affected by the interaction between diet restriction and extra load. Wing stroke amplitude significantly increased after DR6 treatment, while the relative downstroke duration significantly decreased. The stroke plane angle significantly increased after DR6 treatment only in the load-free condition. In addition, the sparrows adjusted their body angle and stroke plane angle in response to the extra load, but stroke amplitude and wingbeat frequency remained unchanged. Therefore, birds can maintain and even enhance their flight performance by adjusting flight kinematics and postures after a short-term mass loss.

Ventral wing hairs provide tactile feedback for aerial prey capture in the big brown bat, Eptesicus fuscus.

Bats rely on their hand-wings to execute agile flight maneuvers, to grasp objects, and cradle young. Embedded in the dorsal and ventral membranes of bat wings are microscopic hairs. Past research findings implicate dorsal wing hairs in airflow sensing for flight control, but the function of ventral wing hairs has not been previously investigated. Here, we test the hypothesis that ventral wing hairs carry mechanosensory signals for flight control, prey capture, and handling. To test this hypothesis, we used synchronized high-speed stereo video and audio recordings to quantify flight and echolocation behaviors of big brown bats (Eptesicus fuscus) engaged in an aerial insect capture task. We analyzed prey-capture strategy and performance, along with flight kinematics, before and after depilation of microscopic hairs from the bat's ventral wing and tail membranes. We found that ventral wing hair depilation significantly impaired the bat's prey-capture performance. Interestingly, ventral wing hair depilation also produced increases in the bat's flight speed, an effect previously attributed exclusively to airflow sensing along the dorsal wing surface. These findings demonstrate that microscopic hairs embedded in the ventral wing and tail membranes of insectivorous bats provide mechanosensory feedback for prey handling and flight control.

A hull reconstruction-reprojection method for pose estimation of free-flying fruit flies.

Understanding the mechanisms of insect flight requires high-quality data of free-flight kinematics, e.g. for comparative studies or genetic screens. Although recent improvements in high-speed videography allow us to acquire large amounts of free-flight data, a significant bottleneck is automatically extracting accurate body and wing kinematics. Here, we present an experimental system and a hull reconstruction-reprojection algorithm for measuring the flight kinematics of fruit flies. The experimental system can automatically record hundreds of flight events per day. Our algorithm resolves a significant portion of the occlusions in this system by a reconstruction-reprojection scheme that integrates information from all cameras. Wing and body kinematics, including wing deformation, are then extracted from the hulls of the wing boundaries and body. This model-free method is fully automatic, accurate and open source, and can be readily adjusted for different camera configurations or insect species.

Pitch release speed predictors for division I collegiate baseball players

BACKGROUND: Analytics, to quantify baseball pitch metrics, take on many forms and are unlike earlier methods to assess performance. OBJECTIVE: Quantify associations of flight kinematic and anthropometric variables on pitch release speed. METHODS: Male college-age pitchers (n= 182) from 2021 Division I games provided data. A 3D radar system collected data. Fixed effects regression OLS models analyzed data for sliders, changeups, curveballs, and fastballs. RESULTS: Spin rate (r= 0.017–0.514, p< 0.05) and vertical break (r= 0.374–0.703, p< 0.05) were positively associated with pitch release speed per pitch type. Release height (r=-0.286–0.051, p<-0.05) and pitch extension (r=-0.176–0.43, p< 0.05) were negatively associated with pitch release speed per pitch type except sliders. Spin axis had a negative association with pitch release speed for fastballs (r=-0.235, p< 0.05) and sliders (r=-0.311, p< 0.05), and a positive association (r= 0.029, p< 0.05) with curveball pitch release speed. Weight only related to pitch release speed for fastballs (r=-0.315, p< 0.05). Height did not impact pitch release speed. CONCLUSIONS: Results refute long-held beliefs of anthropometry’s influence on performance and instead reveal flight kinematics’ impact on baseball pitch release speed.

Compensation for a costly ornament depends on the development of flight performance in stalk-eyed flies

Several species of stalk-eyed flies exhibit exaggerated sexual dimorphism where females favor males with longer eyespans. Longer eyespan increases a fly’s moment of inertia, and may, therefore, impact flight behavior and fitness, specifically maneuverability and predator evasion. However, these putative costs may be ameliorated by co-selection for compensatory traits, as flies with longer eyespans tend to have larger thoraces and wings, which allows them to perform turns similar to flies with shorter eyespans. Furthermore, the capacity to compensate for a potentially costly ornament may not be fixed across the life-history of the adult stage, as stalk-eyed flies achieve sexual maturity at 3-4 weeks of age, accompanied by significant growth of reproductive tissues and organs. Thus, growth of the abdomen and body mass over time may impose constraints on flight performance that may affect whether an adult reaches the age of reproductive viability. The purpose of this study was to investigate the flight performance of stalk-eyed flies and its relationship to body morphology and development. The flight performance of 1-to-30 day oldTeleopsis dalmanni(n=124) andDiasemopsis meigenii(n=83) were assessed by presenting normoxic, variable-density mixtures of heliox (O2, N2and He) in 10% increments ranging from air to pure heliox; the least-dense gas allowing flight represented maximal performance. Flight kinematics were analyzed using high-speed (5930fps) videography. Immediately following flight assessment, flies were euthanized, photographed, dissected and weighed. In both species, total body mass, thorax and abdominal mass increased across age. Wing kinematics and maximal flight capacity were associated with thorax mass, and increased with age as flies became heavier. Although flies with longer eyespans were indeed heavier, they had larger wings and thoraces; however, maximal flight capacity and kinematics were generally independent of eyespan. Thus, bearing long eye-stalks did not impair flight performance, nor did the increase in mass attributable to reproductive maturation. Instead, variation in flight performance appears associated with the development of the flight motor, and improved ratio of thorax-to-total mass, across age.

Biodiversity and big data to investigate the link between biosonar sensing and flight control in bats

Any animal with dexterous mobility in complex natural environments needs powerful systems for sensing and mobility that also have to be well-integrated with each other. Echolocating bats that hunt in dense vegetation rely on biosonar integrated with flapping flight to accomplish this. The low-dimensional nature of the biosonar inputs together with the complexity of the bats' flight apparatus make this coupling a fundamental scientific challenge. To understand how bats can control the many degrees of freedom of their wings based on external information that is conveyed by only two one-dimensional echo trains, a flight tunnel has been instrumented with synchronized high-speed video cameras and ultrasonic microphones. The array recordings can provide data volumes that are large enough to enable deep-learning analyses of the biosonar echoes and the flight kinematics. These analyses will be applied to reducing the dimensionality of ultrasonic inputs, the kinematic outputs, and discovering the relationship between the essential dimensions of biosonar and flight. The tunnel has been installed on the island of Borneo to take advantage of the local bat biodiversity as a source of variability that can be exploited in a comparative approach to identify functional traits that are essential to sensorimotor integration in echolocating bats.

The Lift Effects of Chordwise Wing Deformation and Body Angle on Low-Speed Flying Butterflies.

This work investigates the effects of body angle and wing deformation on the lift of free-flying butterflies. The flight kinematics were recorded using three high-speed cameras, and particle-image velocimetry (PIV) was used to analyze the transient flow field around the butterfly. Parametric studies via numerical simulations were also conducted to examine the force generation of the wing by fixing different body angles and amplifying the chordwise deformation. The results show that appropriately amplifying chordwise deformation enhances wing performance due to an increase in the strength of the vortex and a more stabilized attached vortex. The wing undergoes a significant chordwise deformation, which can generate a larger lift coefficient than that with a higher body angle, resulting in a 14% increase compared to a lower chordwise deformation and body angle. This effect is due to the leading-edge vortex attached to the curved wing, which alters the force from horizontal to vertical. It, therefore, produces more efficient lift during flight. These findings reveal that the chordwise deformation of the wing and the body angle could increase the lift of the butterfly. This work was inspired by real butterfly flight, and the results could provide valuable knowledge about lift generation for designing microaerial vehicles.

Experiments and Analysis of Mosquito Flight Behaviors in a Wind Tunnel: An Introduction.

Mosquitoes detect and navigate to important resources, like a host, using combinations of different sensory stimuli. The relative importance of the sensory cues can change as the mosquito gets closer to their target. Other factors, both internal and external, can also influence the mosquito behavior. A mechanistic understanding of these sensory stimuli, and how they impact mosquito navigation, can now be readily studied using wind tunnels and associated computer vision systems. In this introduction, we present a behavioral paradigm using a wind tunnel for flight behavior analysis. The wind tunnel's large size with its associated cameras and software system for analysis of the mosquito flight tracks can be sophisticated and sometimes cost-prohibitive. Nevertheless, the wind tunnel's flexibility in allowing the testing of multimodal stimuli and scaling of environmental stimuli makes it possible to reproduce conditions from the field and test them in the laboratory, while also allowing the observation of natural flight kinematics.

Quantifying the Aerodynamic Power Required for Flight and Testing for Adaptive Wind Drift in Passion-Vine Butterflies Heliconius sara (Lepidoptera: Nymphalidae)

Although theoretical work on optimal migration has been largely restricted to birds, relevant free-flight data are now becoming available for migratory insects. Here we report, for the first time in passion-vine butterflies, that Heliconius sara migrates directionally. To test optimal migration models for insects, we quantified the aerodynamic power curve for free-flying H. sara as they migrated across the Panama Canal. Using synchronized stereo-images from high-speed video cameras, we reconstructed three-dimensional flight kinematics of H. sara migrating naturally across the Panama Canal. We also reconstructed flight kinematics from a single-camera view of butterflies flying through a flight tunnel. We calculated the power requirements for flight for H. sara over a range of flight velocities. The relationship between aerodynamic power and velocity was "J"-shaped across the measured velocities with a minimum power velocity of 0.9 m/s and a maximum range velocity of 2.25 m/s. Migrating H. sara did not compensate for crosswind drift. Changes in airspeed with tailwind drift were consistent with the null hypothesis that H. sara did not compensate for tailwind drift, but they were also not significantly different from those predicted to maximize the migratory range of the insects.

Приведение возмущенного движения точки на базовую траекторию при наличии геометрических ограничений на дополнительные управления

The deriving the perturbed material point motion in a small neighborhood of the base trajectory problem is solved in this paper. Assumed that geometric constraints in the form of convex compact sets are imposed on the additional controls. In particular, the cases of spheres, ellipsoids and rectangular parallelepipeds were considered. As a result of the constructed control, all the requirements for the kinematics of the point flight were satisfied: the point hitting prohibition with given regions and the necessity of its location in the given vertical strip above the ground surface. The numerical experiment confirmed the effectiveness of the proposed algorithm.

Investigating the integration of biosonar sensing and flight control in bats on Borneo

Many bat species rely on biosonar as their primary source of sensory information about their environments. Species that are able to navigate amid dense vegetation use this biosonar information to guide highly dexterous flight maneuvers. Understanding the connection between biosonar inputs and flight outputs poses a challenge, because the flight apparatus of bats has the most degrees of freedom of any flight system—whether natural or man-made. At the same time, the biosonar inputs consist of just two one-dimensional acoustic time signals (i.e., echoes received at the two ears). Due to the complexity and large variability in the echoes and the flight maneuvers of bats, understanding the input-output relationships requires the ability to collect large amounts of quantitative data on the acoustics and the flight kinematics. In addition, comparing different bat species could offer a window into the principles behind the evolutionary co-adaptation of biosonar and flight. To accomplish this, a cylindrical flight tunnel that integrates synchronized arrays of 50 high-speed video cameras and 32 ultrasonic microphones has been set up on the island of Borneo. This instrument is complemented by a set of custom deep-learning techniques that can handle the large amounts of data that are being produced.

Machine learning methods for reconstructing the acoustic fields of bat biosonar

Understanding the relationships between biosonar and flight in bats requires synchronized recordings of the echo inputs and the flight kinematics of the animals. Here, integrated arrays of 50 high-speed camera and 32 ultrasonic microphones have been set up to collect the data that is necessary for achieving this goal. The arrays are set up to record bats as they fly through an an obstacle course inside a cylindrical tunnel. Due to the complexity of the received signals in these scenarios, we have been developing custom strategies that rely on a combination of compressed sensing and deep learning to reconstruct the acoustic field inside the tunnel from the microphone-array measurements. By using a combination of the high-speed video and acoustic data, it can be attempted to determine the bat's location in the array from the image data and then reconstruct the properties of the sound fields that were emitted and received at this position using the acoustic array data. The goal of this research is to eventually determine the dynamic characteristics of the bat's biosonar emissions such as beampatterns and potentially time-variant characteristics as well as the biosonar inputs that the bats rely on for controlling their flight behaviors.

Divergence of climbing escape flight performance in Morpho butterflies living in different microhabitats.

ABSTRACTHabitat specialization can influence the evolution of animal movement in promoting divergent locomotor abilities adapted to contrasting environmental conditions, differences in vegetation clutter or predatory communities. While the effect of habitat on the evolution of locomotion and particularly escape performance has been well investigated in terrestrial animals, it remains understudied in flying animals. Here, we investigated whether specialization of Morpho butterfly species into different vertical strata of the Amazonian forest affects the performance of upward escape flight manoeuvres. Using stereoscopic high-speed videography, we compared the climbing flight kinematics of seven Morpho species living either in the forest canopy or in the understory. We show that butterflies from canopy species display strikingly higher climbing speed and steeper ascent angle compared with understory species. Although climbing speed increased with wing speed and angle of attack, the higher climb angle observed in canopy species was best explained by their higher body pitch angle, resulting in more upward-directed aerodynamic thrust forces. Climb angle also scales positively with weight-normalized wing area, and this weight-normalized wing area was higher in canopy species. This shows that a combined divergence in flight behaviour and morphology contributes to the evolution of increased climbing flight abilities in canopy species.

AESTHETIC RATIOS OF FLIGHT - HOW OBSERVER EXPERTISE AND AESTHETIC PERCEPTION ARE RELATED TO WEBSTER FREERUNNING SKILL FLIGHT KINEMATICS

The perception of (motion) aesthetics is related to the circumstances of the object, the observer, and the given context. The central question of this study is whether the perception of motion aesthetics is related to a motor skill’s ratio of flight kinematics and the observer’s sensory-motor experiences. Motor skills, perceived as more aesthetic, are hypothesized to show kinematic flight ratios near the golden ratio. Motor skills, perceived as less aesthetic, are hypothesized to show kinematic flight ratios farther away from the golden ratio. Furthermore, this relationship is hypothesized to be related to the observer’s sensory-motor experience. Therefore, 36 participants (12 freerunning experts, 12 freerunning novices, and 12 laypeople) were asked to indicate their perception of motion aesthetics when watching video sequences of different freerunning performances. The results indicate that kinematic flight ratios and the observer’s sensory-motor experience are related to the aesthetic perception of the freerunning skill. As hypothesized, kinematic ratios of Webster performances perceived as more aesthetic are closer to the golden ratio, and Webster performances perceived as less aesthetic are farther away from the golden ratio; this is significant for expert and novice freerunners, but not for laypeople. Thus, we conclude that the aesthetic perception of complex motor skills is related to kinematic flight ratios and the observer’s sensory-motor expertise. Future work should incorporate such knowledge about kinematic ratios and how to address them during motor skill performances to create and perform aesthetically pleasing complex motor skills.

A Review of Bat-Inspired Shape Morphing Robotic Design

AbstractBy virtue of distinguished wing shape morphing characteristics, the unrivaled agility and flight maneuverability of bats have inspired scientists and engineers to develop novel forms of robots that can fly like bats. The unique wing conformations, flight kinematics, and aerodynamics offer significant advantages over the conventional form of miniature air vehicle in terms of quiet, safe operations, improved efficiency, and enhanced maneuverability. Meanwhile, they also pose substantial challenges for robot design from multiple perspectives, including mechanical design, sensing, control, etc. The practical benefits and technical bottleneck have motivated the development of bat-inspired robots in recent years. The purpose of this paper is to summarize the designing principles and report current state-of-the-art of bat-inspired robot designs, emphasizing the respective distinguishing features of each paradigm, along with the room for further improvement. Rather than showcasing advancement in wing materials, we will focus on the mechanical design and control methodology. This paper will help researchers new in this realm to get familiar with the bat-inspired robots by adopting features from existing designs. It also concludes technical challenges associated with future development, involving biological research, aerodynamic modeling, mechanical design, and control technique.

The dynamic model of a high-rise firefighting drone

The utilization of unmanned aerial vehicles (UAVs) in high-rise firefighting operations is the right solution for reaching the fire scene on high floors quickly and effectively. The article proposes a quadrotor-type firefighting UAV model carrying a launcher to launch a missile containing fire extinguishing powders into a fire. The kinematic model describing the flight kinematics of this UAV model is built based on the Newton – Euler method when the device is in normal motion and at the time of launching a firefighting missile. The results from the simulation testing the validity of the kinematic model and the simulation of the motion of the UAV show that the variation of Euler angles, flight angles, and aerodynamic angles during a flight are within an acceptable range and overload guarantee in flight. The UAV flew to the correct position to launch the required fire-extinguishing ammunition. The results of the research are the basis for building a control system of high-rise firefighting drones in Vietnam.