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Flight dynamics in Drosophila through a dynamically-scaled robotic approach

Citation

Elzinga, Michael John (2013) Flight dynamics in Drosophila through a dynamically-scaled robotic approach. Dissertation (Ph.D.), California Institute of Technology. http://resolver.caltech.edu/CaltechTHESIS:06072013-110839676

Abstract

Flies are particularly adept at balancing the competing demands of delay tolerance, performance, and robustness during flight, which invites thoughtful examination of their multimodal feedback architecture. This dissertation examines stabilization requirements for inner-loop feedback strategies in the flapping flight of Drosophila, the fruit fly, against the backdrop of sensorimotor transformations present in the animal. Flies have evolved multiple specializations to reduce sensorimotor latency, but sensory delay during flight is still significant on the timescale of body dynamics. I explored the effect of sensor delay on flight stability and performance for yaw turns using a dynamically-scaled robot equipped with a real-time feedback system that performed active turns in response to measured yaw torque. The results show a fundamental tradeoff between sensor delay and permissible feedback gain, and suggest that fast mechanosensory feedback provides a source of active damping that compliments that contributed by passive effects. Presented in the context of these findings, a control architecture whereby a haltere-mediated inner-loop proportional controller provides damping for slower visually-mediated feedback is consistent with tethered-flight measurements, free-flight observations, and engineering design principles. Additionally, I investigated how flies adjust stroke features to regulate and stabilize level forward flight. The results suggest that few changes to hovering kinematics are actually required to meet steady-state lift and thrust requirements at different flight speeds, and the primary driver of equilibrium velocity is the aerodynamic pitch moment. This finding is consistent with prior hypotheses and observations regarding the relationship between body pitch and flight speed in fruit flies. The results also show that the dynamics may be stabilized with additional pitch damping, but the magnitude of required damping increases with flight speed. I posit that differences in stroke deviation between the upstroke and downstroke might play a critical role in this stabilization. Fast mechanosensory feedback of the pitch rate could enable active damping, which would inherently exhibit gain scheduling with flight speed if pitch torque is regulated by adjusting stroke deviation. Such a control scheme would provide an elegant solution for flight stabilization across a wide range of flight speeds.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:flapping flight, insect flight dynamics
Degree Grantor:California Institute of Technology
Division:Engineering and Applied Science
Major Option:Mechanical Engineering
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Dickinson, Michael H.
Thesis Committee:
  • Murray, Richard M. (chair)
  • Bhattacharya, Kaushik
  • Burdick, Joel Wakeman
  • Dickinson, Michael H.
Defense Date:14 December 2012
Non-Caltech Author Email:michael.j.elzinga (AT) gmail.com
Record Number:CaltechTHESIS:06072013-110839676
Persistent URL:http://resolver.caltech.edu/CaltechTHESIS:06072013-110839676
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:7864
Collection:CaltechTHESIS
Deposited By: Michael Elzinga
Deposited On:07 Jun 2013 23:44
Last Modified:11 Jun 2014 17:34

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