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Biology subjects

Bomphrey, R. J.

Publications and source records attributed to Bomphrey, R. J..

3 recordsLinked to original sources

Mechanosensory representation of wing deformations

Locomotor control is facilitated by mechanosensory inputs that report how the body interacts with a physical medium. Effective representation of compliant wing deformations is particularly challenging due to the many degrees of freedom. Structural configurations can constrain the stimulus space, and strategic placement of sensors can simplify computation. Here, we measured and modelled wing displacement fields and characterized spatiotemporal encoding of the wing mechanosensors. Our data show how dragonfly wing architecture prescribes deformation modes consistent across models and measurements. We found that the wings state under normal flapping conditions is detected by the spike timing of few sensors, with additional sensors recruited under perturbation. The functional integration of wing biomechanics and sensor placement enables a straightforward solution for information transfer. Significance StatementMany systems in nature precisely control highly deformable structures, yet monitoring structural deformations has posed a significant challenge for biologists and engineers. By measuring and modelling the intricate structure of compliant dragonfly wings, we demonstrate an elegant solution for mechanosensory representation. We show that the functional integration of natural wing biomechanics and sensor placement provides a straightforward solution for information transfer. Wing morphology passively constrains the range of natural deformations, producing strain patterns that align with sensor locations, allowing them to monitor the wing using a simple timing-dependent encoding strategy. The way insects monitor aerodynamic and inertial forces via wing deformations during flight could apply to many sensory systems in nature and inspire artificial neural networks for controlling diverse dynamic systems.

neuroscience↗

Dynamics of hinged wings in strong upward gusts

A birds wings are articulated to its body via highly mobile shoulder joints. The wings possess an impressive range of motion, which allows for movements that can modulate the production of aerodynamic load in flight. This is crucial for stability and control--particularly in gusty or turbulent environments. In this study, we develop a dynamics model to examine how a bird-scale gliding aircraft can use wing-root hinges (analogous to avian shoulder joints) to reject the initial impact of a strong upward gust. Our idea requires that the spanwise centre of pressure and the centre of percussion of the hinging wing start, and stay, in good initial alignment (the centre of percussion here is related to the idea of a sweet spot on a bat, as in cricket or baseball). We propose a method for achieving this rejection passively, for which the essential ingredients are: (i) well-considered lift and mass distributions; (ii) constant-torque hinges; and (iii) a wing whose sections stall softly. When configured correctly, the gusted wings will first pivot on their hinges without disturbing the fuselage of the aircraft, affording time for other corrective actions to engage. We expect this system to enhance the control of aircraft that fly in gusty conditions.

bioengineering↗

From wing shape to fluid dynamics in the barn owl (Tyto alba)

Birds morph their wings and tail in order to glide under a wide range of aerodynamic conditions. Gross wing morphing has been described in a multitude of studies, but the finer details of wing morphing are still unknown. Here, we measured the changes in wing shape and pose in a barn owl, Tyto alba, when gliding across a range of fifteen self-selected speeds. We found that T. alba does not use fine-wing shape control to glide at slow speeds in steady conditions, with the measured wing shapes being highly consistent across all flights. Instead, T. alba relied upon wing postural control (gross pitch) and changes in both tail shape and pose to modulate aerodynamic force. A consistent wing shape provides an exceptional aerodynamic tool for understanding gliding flight in birds through postural change and tail morphing. This geometry was used as the basis for computational fluid dynamics simulations which gave very similar wake measurements and weight support to those measured in flight. This geometry is provided here to assist other researchers interested in exploring the fluid dynamics behind gliding flight in birds.Competing Interest StatementThe authors have declared no competing interest.View Full Text

zoology↗