voltToForce: Convert voltage data to ground reaction force data

In MorphoFun/kraken: Analyses for bone biomechanics

Convert voltage data to ground reaction force data

Description

Takes voltage data from a multi-axis force platform and then converts those data to ground reation forces. Note: this code was originally written with a force plate that was oriented with the following configuration: Front left = Yellow (Y), Front Right = Pink (P), Back Left = Orange (O), and Back Right = Green (G). Deviations from this configuration may require adjustments in the signage of the GRF data.

Usage

voltToForce(calib, lightStartFrame, startFrame, endFrame, videoHz, forceHz, zeroStart)

Arguments

df	A data.frame of data recorded from 12 channels of a force platform in the following order: 1 column trigger, 4 columns for the verticals, 1 column for the sum of the verticals, 2 columns for the mediolaterals, 1 column for the sum of the mediolaterals, 2 anteroposteriors, and 1 column for the sum of the anteroposteriors.
calib	A vector of numeric data containing the calibrations in the vertical, mediolateral, and anteroposterior directions, respectively.
zeroStart	A numeric / integer value depicting the frame number in which the data move away from the baseline. The data will be zero'd about 1000 sweeps prior to this frame.
lightStartFrame	A numeric / integer value depicting the frame in which the light is triggered on the high-speed video.
startFrame	A numeric / integer value depicting the frame number in which the behavior started (e.g., first contact of the foot onto the force plate)
endFrame	A numeric / integer value depicting the frame number in which the behavior ended (e.g., penultimate frame to the foot lifting off from the force plate.
videoHz	A numeric / integer value depicting the frame rate for the high-speed videos. 100 Hz set as a default.
forceHz	A numeric / integer value depicting the recording rate for the force plate data. 5000 Hz set as a default.
filename	Option to identify the name of the file for indexing later.
saveData	Option to save all of the data from this function as .csv files. Default is set to "no".

Details

These procedures follow the methodology used in Kawano and Blob (2013) and Kawano et al. 2016. It is assumed that the output from the force platform contain 12 channels in the following order: trigger, four verticals, sum of the verticals, two mediolateral, sum of the mediolaterals, two anteroposterior, and the sum of the anteroposteriors.

References

Kawano SM, Blob RW. 2013. Propulsive forces of mudskipper fins and salamander limbs during terrestrial locomotion: implications for the invasion of land. Integrative and Comparative Biology 53(2): 283-294. https://academic.oup.com/icb/article/53/2/283/806410/Propulsive-Forces-of-Mudskipper-Fins-and

Kawano SM, Economy DR, Kennedy MS, Dean D, Blob RW. 2016. Comparative limb bone loading in the humerus and femur of the tiger salamander Ambystoma tigrinum: testing the "mixed-chain" hypothesis for skeletal safety factors. Journal of Experimental Biology 219: 341-353. http://jeb.biologists.org/content/219/3/341

Examples

voltToForce(af01f18, calib = c(-0.7126, 1.3243, 1.3476), lightStartFrame = 276, startFrame = 35, endFrame = 148, zeroStart = 35, filename = "af01f18")

MorphoFun/kraken documentation built on July 2, 2022, 1:13 p.m.