parallelaxis: Parallel axis theory

Description Usage Arguments Value Author(s) Examples

View source: R/mathematicalfunctions.R

Description

Reads in an initial tensor and an offset to compute the transformed tensor. Will be in the same frame of reference as the input tensor.

Usage

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parallelaxis(I, offset_vec, m, cg_a)

Arguments

I

a 3x3 matrix representing the moment of inertia tensor about the center of gravity of the object (kg-m^2).

offset_vec

a 1x3 vector representing the distance (x,y,z) between the objects CG and the arbitrary pt A (m). Vector should always point from the CG to the arbitrary point A.

m

Mass of the object (kg).

cg_a

If input I is about the CG enter "CG" or if I is about an arbitrary axis enter "A".

Value

a 3x3 matrix representing the transformed moment of inertia tensor after a solid body translation defined by the offset vector.

Author(s)

Christina Harvey

Examples

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# refer to the vignette
library(AvInertia)

# load data
data(dat_id_curr, package = "AvInertia")
data(dat_bird_curr, package = "AvInertia")
data(dat_feat_curr, package = "AvInertia")
data(dat_bone_curr, package = "AvInertia")
data(dat_mat, package = "AvInertia")
data(clean_pts, package = "AvInertia")

# 1. Determine the center of gravity of the bird's torso (including the legs)
dat_torsotail_out = massprop_restbody(dat_id_curr, dat_bird_curr)
# 2. Calculate the inertia of the flight feathers about the tip of the calamus
feather_inertia <- compute_feat_inertia(dat_mat, dat_feat_curr, dat_bird_curr)
# 3. Determine the center of gravity of one of the bird's wings
dat_wing_out      = massprop_birdwing(dat_id_curr, dat_bird_curr,
dat_bone_curr, dat_feat_curr, dat_mat, clean_pts,
feather_inertia, plot_var = 0)
# Visualize the center of gravity of each wing component in the x and y axis
dat_wing_out      = massprop_birdwing(dat_id_curr, dat_bird_curr,
dat_bone_curr, dat_feat_curr, dat_mat, clean_pts,
feather_inertia, plot_var = "yx")
# or the y and z axis
dat_wing_out      = massprop_birdwing(dat_id_curr, dat_bird_curr,
dat_bone_curr, dat_feat_curr, dat_mat, clean_pts,
feather_inertia, plot_var = "yz")
# 4. Combine all data and obtain the center of gravity, moment of inertia
# and principal axes of the bird
curr_full_bird      = combine_inertialprop(dat_torsotail_out,dat_wing_out,
dat_wing_out, dat_id_curr, dat_bird_curr, symmetric=TRUE)

AvInertia documentation built on July 22, 2021, 9:08 a.m.