DOI: 10.5061/dryad.34tmpg4tw
title: Data from: Stability and agility trade-offs in spring-wing systems

description: Flying insects are thought to achieve energy-efficient flapping flight by
 storing and releasing elastic energy in their muscles, tendons, and
 thorax. However, "spring-wing" flight systems consisting of
 elastic elements coupled to nonlinear, unsteady aerodynamic forces also
 present possible challenges to generating stable and responsive wing
 motions. The energetic efficiency from resonance in insect flight is
 measured by the Weis-Fogh number (N), which is the ratio of peak inertial
 force to aerodynamic force. In this paper, we present experiments and
 modeling to study how resonance efficiency (which increases with N)
 influences the control responsiveness and perturbation resistance of
 flapping wingbeats. In our first experiments, we provide a step change in
 the input forcing amplitude to a series-elastic spring-wing system and
 observe the response time of the wing amplitude increase. In our second
 experiments, we provide an external fluid flow directed at the flapping
 wing and study the perturbed steady-state wing motion. We evaluate both
 experiments across Weis-Fogh numbers from 1 &lt; N &lt; 10. The
 results indicate that spring-wing systems designed for maximum energetic
 efficiency also experience trade-offs in agility and stability as the
 Weis-Fogh number increases. Our results demonstrate that energetic
 efficiency and wing maneuverability are in conflict in resonant
 spring-wing systems suggesting that mechanical resonance presents
 tradeoffs in insect flight control and stability.
description: # Stability and Agility Trade-offs in Spring-Wing Systems: Paper data
 [https://doi.org/10.5061/dryad.34tmpg4tw](https://doi.org/10.5061/dryad.34tmpg4tw) ## Robotic Spring-Wing Experiment Data [Access this dataset on Dryad](10.5061/dryad.34tmpg4tw) ## Description of Data and File Structure Data is organized into two folders corresponding to the two main experiments presented in the manuscript * riseStep, containing the data from the responsiveness experiments * perturbed, containing the data from the constant flow experiments --- ### Responsiveness Data (riseStep) Data is stored in .mat files using the naming format ``` N[TestNumber]_riseStep_[RepNumber] ([Date]).mat ``` Each .mat file contains * ampReference: a Simulink Parameter containing the target motor amplitude in degrees * fr: the frequency (in Hz) at which the system is driven * runtime: the total time (in seconds) that the experiment is run * ScopeData: A struct object containing the collected experiment data. ScopeData contains the elapsed experiment time (seconds, 1 kHz sampling frequency), and a signals struct that contains four (4) data elements 1. rawAngles: n-by-2 array, first column is the angle of the motor, second is the angle of the wing (degrees). 2. wingAmpDeg: Real-time estimate of wing angle. Used only for tracking (degrees). 3. motAmpDeg: Real-time estimate of motor angle. Used only for tracking (degrees). 4. analogVoltage: 0-5V command to stepper motor controller that drives wing flapping (Volts). --- ### Constant Flow Data (perturbed) Data has the same structure as in the riseStep folder, with the naming format ``` N[TestNumber]_perturbed_[Orientation]_1 ([Date]).mat ``` The orientation refers to the angle the wing makes with the jet of water. "Neutral" is perpendicular to the jet, "minus" is towards the jet, and "plus" is away from the jet. Only the "neutral" and "unperturbed" data is used in the manuscript. The image files in the folder show the wing angle data from all four orientations for each test, normalized to the unperturbed wing amplitude. The images labeled "_var" show just one period of angle data. --- ### Table_weis_fogh_numbers_and_insect_wings.csv This is a csv file with the calculated Weis-Fogh numbers reported in the literature. Columns are organized by Insect group, species, Weis-Fogh number, animal mass, and the reference source. ## Code/Software All data was collected, analyzed and plotted using Simulink Desktop Real-Time and MATLAB (Mathworks). Data files may be accessed using MATLAB or Octave. ---