Flying Drosophila stabilize their vision-based velocity controller by sensing wind with their antennae

Flies and other insects use vision to regulate their groundspeed in flight, enabling them to fly in varying wind conditions. Compared with mechanosensory modalities, however, vision requires a long processing delay (~100 ms) that might introduce instability if operated at high gain. Flies also sense air motion with their antennae, but how this is used in flight control is unknown. We manipulated the antennal function of fruit flies by ablating their aristae, forcing them to rely on vision alone to regulate groundspeed. Arista-ablated flies in flight exhibited significantly greater groundspeed variability than intact flies. We then subjected them to a series of controlled impulsive wind gusts delivered by an air piston and experimentally manipulated antennae and visual feedback. The results show that an antenna-mediated response alters wing motion to cause flies to accelerate in the same direction as the gust. This response opposes flying into a headwind, but flies regularly fly upwind. To resolve this discrepancy, we obtained a dynamic model of the fly’s velocity regulator by fitting parameters of candidate models to our experimental data. The model suggests that the groundspeed variability of arista-ablated flies is the result of unstable feedback oscillations caused by the delay and high gain of visual feedback. The antenna response drives active damping with a shorter delay (~20 ms) to stabilize this regulator, in exchange for increasing the effect of rapid wind disturbances. This provides insight into flies’ multimodal sensory feedback architecture and constitutes a previously unknown role for the antennae

Steady as She Goes: Visual Autocorrelators and Antenna-Mediated Airspeed Feedback in the Control of Flight Dynamics in Fruit Flies and Robotics

Achieving agile autonomous flight by an insect-sized micro aerial vehicle (MAV) will require improved technology that is radically smaller, lighter, and more power-efficient. One animal that has solved the problem is the fly, a virtuoso among insect flyers whose nervous system can perform sophisticated aerial maneuvers under severe computational constraints. This thesis is concerned with understanding and emulating the dynamics of the fly's feedback control system. Because vision is noisy and information rich, processing time may a problem for a fast-moving MAV or fly. By tracking the fruit fly Drosophila melanogaster in free flight in gusts of wind, I found that they incorporate feedback from wind-sensing antennae in a fast feedback loop that dampens the forward-flight dynamics. The slower dynamics are easier to control for long-delay visual feedback, making the fly more robust to the limitations of its visual system. Using the fly as inspiration, I designed a minimal, visual autocorrelation based controller that used a small array of visual sensors to stabilize a fan-actuated hovercraft robot in a narrow corridor. Using a model for correlators developed for the robot, I showed that a uniform array of visual correlators was sufficient to explain the free-flight velocity regulation behavior of flies, rather than a different model. In addition to illustrating the benefits of concurrent scientific analysis and engineering synthesis, the results give new insight into how to control small biological and man-made flying vehicles using limited, noisy sensors

Ink jet deposition of inorganic nanoparticle materials as a route to desktop fabrication of integrated logic and micromachinery

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2000.Includes bibliographical references (p. 43-44).by Sawyer Buckminster Fuller.S.B

A fast flexible ink-jet printing method for patterning networks of neurons in culture

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2003.Includes bibliographical references (p. 77-81).by Sawyer Buckminster Fuller.S.M