Data from: Bird-inspired reflexive morphing enables rudderless flight
Data files
Nov 22, 2024 version files 366.37 MB
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PigeonBot_II_datasupplement.xfl
915.05 KB
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PigeonBotII.STEP
116.87 MB
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README.md
2.93 KB
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WindTunnelTrials.mat
248.58 MB
Abstract
Gliding birds lack a vertical tail, yet they fly stably rudderless in turbulence without needing discrete flaps to steer. In contrast, nearly all airplanes need vertical tails to damp Dutch roll oscillations and control yaw. The few exceptions that lack a vertical tail either leverage differential drag-based yaw actuators or their fixed planforms are carefully tuned for passively stable Dutch roll and proverse yaw. Biologists hypothesize that birds stabilize and control gliding flight without rudders by using their wing and tail reflexes, but no rudderless airplane has a morphing wing or tail that can change shape like a bird. Our rudderless biohybrid robot, PigeonBot II, can indeed damp its Dutch roll instability (caused by lacking vertical tail) and control flight by morphing its biomimetic wing and tail reflexively like a bird. The bird-inspired adaptive reflexive controller was tuned in a wind tunnel to mitigate turbulent perturbations, which enables PigeonBot II to fly autonomously in the atmosphere with pigeonlike poses. This work is a mechanistic confirmation of how birds accomplish rudderless flight via reflex functions, and it can inspire rudderless aircraft with reduced radar signature and increased efficacy.
Here, we provide the raw wind tunnel data for PigeonBot II with 81 total variations of wing and tail morph, angle of attack, and morph actuator mixing. The wind tunnel data includes roll tracking data and responses in varying turbulence until control failure. We also provide a CAD file and dynamic stability simulation file for PigeonBot II.
https://doi.org/10.5061/dryad.zkh1893h5
Description of the data and file structure
PigeonBotII.STEP
PigeonBotII.STEP is a STEP AP214 3D CAD file of PigeonBot II.
Software: Prepared in Solidworks 2023. Compatible with most CAD software. A free web-based alternative to view this file is Autodesk Viewer.
PigeonBot_II_datasupplement.xfl
PigeonBot_II_datasupplement.xfl is a xflr5 project file for simulating open-loop dynamic stability of PigeonBot II's three-by-three wing and tail morph combinations.
Software: Prepared in xflr5 v6.61. xflr5 is free.
WindTunnelTrials.mat
WindTunnelTrials.mat is a MATLAB data file containing PigeonBot II virtual flight data in the wind tunnel.
Software: Prepared in MATLAB R2018b. Free alternatives are HDF5 for Python or GNU Octave.
Its contents are described below:
The Freq
struct contains data for 15deg roll amplitude tracking data over a frequency sweep with yaw damper and roll PID control.
- The variables
[VAR]
contained withinFreq
are:ATT
: 3D vehicle attitudeRCOU
: raw servo outputsARSP
: airspeedIMU
: IMU dataPIDY
: Yaw PID loop valuesPIDP
: Pitch PID loop valuesPIDR
: Roll PID loop values
- Further definitions of each variable format can be found in
[VAR]_label
. - The variables are 4D cells, and corresponding data can be accessed by specifying experimental parameters from 1 to 3 as follows:
Freq.[VAR](Devidx,AoAidx,wingidx,tailidx)
- The index mapping is as follows:
Devidx
: 1, K_dev = 1, K_tilt = 0.125; 2, K_dev = 2, K_tilt = 0.25; 3, K_dev = 4, K_tilt = 0.5.AoAidx
: 1, AoA = cruise-3deg; 2, AoA = cruise; 3, AoA = cruise+3deg.wingidx
: 1, tucked wing; 2, middle wing; 3, spread wing.tailidx
: 1, tucked tail; 2, middle tail; 3, spread tail.
The Static
struct contains data for open loop (Static.NoCtrl
) and yaw damper only (Static.YawDamp
) dynamics. Access the data the same indexing as with the Freq
struct.
The Turb
struct contains data for tests in varying turbulence levels. Access the data similarly as with the Freq
struct, except add an index to define the turbulence level:
Turb.VAR(Devidx,AoAidx,wingidx,tailidx,turbidx)
- where
turbidx
refers to a mapping of turbulence intensity (TI%) levels: 1, 3%; 2, 6%; 3, 9%; 4, 12%; 5, 15%; 6, 18%; 7, 21%.
- where
The Tune
struct contains data for the tuned gains for each trial. Access the data with the same indexing as with the Freq
struct
Tune.YawDamp
contains the K_D gain for the yaw damper mapped to tail tilt.Tune.P
,Tune.I
, andTune.D
contain PID gains for the roll controller.Tune.Elev
contains the tail elevation for each trial.