Secrets of bird and insect flight revealed
The DCBIF (Flight dynamics and control of birds and insects) project studied how birds and insects use vision to stabilise and control their flight. This involved the use of trained birds of prey and a virtual reality flight simulator for insects, which measured the tiny forces and torques exerted by insects while in flight. Results showed that insects responded to simulated rotations of their visual field by producing torques that were controlled in a way that helped to stabilise and steer flight. The team also found that by turning their heads, insects were able to see a much faster range of motions than they otherwise could have. Field experiments with trained eagles and falcons showed that birds move in a similar way. Once they have observed themselves moving through the air, birds and insects must then apply this information. Therefore, DCBIF studied how birds and insects control their wingbeats, and in particular how they adjust the shape of their wings in order to control their flight. This question was investigated using high-speed cameras in both the laboratory and the field to measure the details of wing movement and deformation in a trained eagle and a range of insects. Computational techniques were also used to predict the aerodynamic forces involved. It was found that wing deformation improved the aerodynamic lift produced by an insect by 70 %. The inner workings of the insect flight motor were studied using a new technique that exposed the insect to X-ray illumination in flight. The insect was spun around to enable the flight motor to be viewed from all angles and to encourage the insect to turn by varying its wingbeat. By combining radiographic images taken from different angles at the same stage of the wingbeat, researchers were able to reconstruct in 3D(opens in new window) the musculoskeletal movements that power and control the wingbeat. Insights gained from DCBIF are now being applied to control of the next generation of small unmanned devices capable of flight.
