Bird-inspired Velocity Optimization for UAVs in the Urban Environment

Williamson, Cara; Spelt, Anouk; Windsor, Shane

doi:10.2514/6.2020-1948

Cited by 4 publications

(4 citation statements)

References 47 publications

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“…We selected gulls as our study species because their non-planar wing shape is known to be actively controlled by elbow and wrist manipulation [5]. In addition, gulls are a good model species for multifunctional UAVs as they are generalist flyers, using a wide variety of flight styles from steady glides to sudden manoeuvres [24,25]. Next, we aligned and simplified each extracted wing shape ( n = 1031) and connected these wings to a gull-shaped body (figure 1 b ).…”

Section: Introductionmentioning

confidence: 99%

Gull-inspired joint-driven wing morphing allows adaptive longitudinal flight control

Harvey

Baliga

Goates

et al. 2021

J. R. Soc. Interface.

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Birds dynamically adapt to disparate flight behaviours and unpredictable environments by actively manipulating their skeletal joints to change their wing shape. This in-flight adaptability has inspired many unmanned aerial vehicle (UAV) wings, which predominately morph within a single geometric plane. By contrast, avian joint-driven wing morphing produces a diverse set of non-planar wing shapes. Here, we investigated if joint-driven wing morphing is desirable for UAVs by quantifying the longitudinal aerodynamic characteristics of gull-inspired wing-body configurations. We used a numerical lifting-line algorithm (MachUpX) to determine the aerodynamic loads across the range of motion of the elbow and wrist, which was validated with wind tunnel tests using three-dimensional printed wing-body models. We found that joint-driven wing morphing effectively controls lift, pitching moment and static margin, but other mechanisms are required to trim. Within the range of wing extension capability, specific paths of joint motion (trajectories) permit distinct longitudinal flight control strategies. We identified two unique trajectories that decoupled stability from lift and pitching moment generation. Further, extension along the trajectory inherent to the musculoskeletal linkage system produced the largest changes to the investigated aerodynamic properties. Collectively, our results show that gull-inspired joint-driven wing morphing allows adaptive longitudinal flight control and could promote multifunctional UAV designs.

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Section: Introductionmentioning

confidence: 99%

Gull-inspired joint-driven wing morphing allows adaptive longitudinal flight control

Harvey

Baliga

Goates

et al. 2021

J. R. Soc. Interface.

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“…Pennycuick improved these estimations by incorporating a parameter that accounts for a bird's variable wingspan [110]. This programme is commonly used to estimate a bird's best glide speed and then compare to the true measured gliding airspeeds, which has had varied success across different species and studies [12,14,103,161].…”

Section: Theoretical Prediction Of Aerodynamic Efficiencymentioning

confidence: 99%

“…In addition, we focussed only on steady gliding flight rather than soaring flight to allow direct comparisons across species and to UAVs. However, identifying a birds' flight path and analysing the potential benefits and applicability to UAV path planning is an ongoing area of research [82,97,98].…”

Section: Perspectives and Future Directionsmentioning

confidence: 99%

“…The albatross and kestrel both provide examples of soaring flight because they extract energy from the environment, such as the shear layer over the ocean (a form of dynamic soaring) or wind deflected by cliffs (static soaring) [11][12][13]. Soaring flight is one of the most common forms of non-flapping bird flight where soaring performance is dependent on a flyer's morphology, flight path taken and the velocity gradients in the environment [12,14]. The latter two parameters are often dictated by an individual's behaviour or local environment.…”

Section: Introductionmentioning

confidence: 99%

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Aerodynamic efficiency of gliding birds vs comparable UAVs: a review

Harvey¹,

Inman²

2021

Bioinspir. Biomim.

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Here, we reviewed published aerodynamic efficiencies of gliding birds and similar sized unmanned aerial vehicles (UAVs) motivated by a fundamental question: are gliding birds more efficient than comparable UAVs? Despite a multitude of studies that have quantified the aerodynamic efficiency of gliding birds, there is no comprehensive summary of these results. This lack of consolidated information inhibits a true comparison between birds and UAVs. Such a comparison is complicated by variable uncertainty levels between the different techniques used to predict avian efficiency. To support our comparative approach, we began by surveying theoretical and experimental estimates of avian aerodynamic efficiency and investigating the uncertainty associated with each estimation method. We found that the methodology used by a study affects the estimated efficiency and can lead to incongruent conclusions on gliding bird aerodynamic efficiency. Our survey showed that studies on live birds gliding in wind tunnels provide a reliable minimum estimate of a birds’ aerodynamic efficiency while simultaneously quantifying the wing configurations used in flight. Next, we surveyed the aeronautical literature to collect the published aerodynamic efficiencies of similar-sized, non-copter UAVs. The compiled information allowed a direct comparison of UAVs and gliding birds. Contrary to our expectation, we found that there is no definitive evidence that any gliding bird species is either more or less efficient than a comparable UAV. This non-result highlights a critical need for new technology and analytical advances that can reduce the uncertainty associated with estimating a gliding bird’s aerodynamic efficiency. Nevertheless, our survey indicated that species flying within subcritical Reynolds number regimes may inspire UAV designs that can extend their operational range to efficiently operate in subcritical regimes. The survey results provided here point the way forward for research into avian gliding flight and enable informed UAV designs.

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