massprop_muscles: Muscle mass properties

In AvInertia: Calculate the Inertial Properties of a Flying Bird

Muscle mass properties

Description

Calculate the moment of inertia of a muscle modeled as a solid cylinder distributed along the bone length

Usage

massprop_muscles(m, rho, l, start, end)

Arguments

m	Mass of muscle (kg).
rho	Density of muscle (kg/m^3).
l	Length of the muscle group (m).
start	a 1x3 vector (x,y,z) representing the 3D point where bone starts. Frame of reference: VRP | Origin: VRP.
end	a 1x3 vector (x,y,z) representing the 3D point where bone ends. Frame of reference: VRP | Origin: VRP.

Value

This function returns a list that includes:

• Ia 3x3 matrix representing the moment of inertia tensor of a muscle modeled as a solid cylinder distributed along the bone length.

• CGa 1x3 vector representing the center of gravity position of a muscle modeled as a solid cylinder distributed along the bone length.

• ma double that returns the input muscle mass.

Warning

Parallel axis theorem does not apply between two arbitrary points. One point must be the object's center of gravity.

Author(s)

Christina Harvey

Examples

# 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 March 24, 2022, 5:07 p.m.