ABSTRACT
Flapping insect flight is a complex and beautiful phenomenon that relies on fast, active control mechanisms to counter aerodynamic instability. To directly investigate how freely flying Drosophila melanogaster control their body pitch angle against such instability, we perturbed them using impulsive mechanical torques and filmed their corrective maneuvers with high-speed video. Combining experimental observations and numerical simulation, we found that flies correct for pitch deflections of up to 40 deg in 29±8 ms by bilaterally modulating their wings' front-most stroke angle in a manner well described by a linear proportional–integral (PI) controller. Flies initiate this corrective process only 10±2 ms after the perturbation onset, indicating that pitch stabilization involves a fast reflex response. Remarkably, flies can also correct for very large-amplitude pitch perturbations – greater than 150 deg – providing a regime in which to probe the limits of the linear-response framework. Together with previous studies regarding yaw and roll control, our results on pitch show that flies' stabilization of each of these body angles is consistent with PI control.
FOOTNOTES
Competing interests
The authors declare no competing or financial interests.
Author contributions
S.C.W. and L.C. conducted experiments and collected data. T.B. and S.C.W. developed code for data analysis and simulation. S.C.W. analyzed the data. S.C.W., T.B. and I.C. wrote the paper.
Funding
This work was supported in part by a National Science Foundation (NSF) DMR award (no. 1056662) and in part by an Army Research Office (ARO) award (no. 61651-EG). S.C.W. was supported by a National Defense Science and Engineering Graduate (NDSEG) Fellowship. T.B. was supported by the Cross Disciplinary Post-Doctoral Fellowship of the Human Frontier Science Program.
Supplementary information
Supplementary information available online at http://jeb.biologists.org/lookup/suppl/doi:10.1242/jeb.122622/-/DC1
- © 2015. Published by The Company of Biologists Ltd
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