massprop_torso {AvInertia} R Documentation

## Torso and leg mass properties

### Description

Calculate the moment of inertia of a head modeled as a solid cone

### Usage

```massprop_torso(
m_true,
m_legs,
w_max,
h_max,
l_bmax,
w_leg,
l_leg,
l_tot,
CG_true_x,
CG_true_z,
start,
end
)
```

### Arguments

 `m_true` Mass of the torso and legs - no tail (kg) `m_legs` Mass of the legs only (kg) `w_max` Maximum width of the body (m) `h_max` Maximum height of the body (m) `l_bmax` x location of the maximum width of the body (m) `w_leg` width of the body at leg insertion (m) `l_leg` x location of the leg insertion point (m) `l_tot` length of body from clavicle to beginning of the tail (m) `CG_true_x` x location of the CG for the torso and legs, origin is at the VRP, measured positive if aft of the VRP (m) `CG_true_z` z location of the CG for the torso and legs, origin is at the VRP (m) `start` a 1x3 vector (x,y,z) representing the 3D point where torso starts. Frame of reference: VRP | Origin: VRP `end` a 1x3 vector (x,y,z) representing the 3D point where tail 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 the torso and leg composite body

• CGa 1x3 vector representing the center of gravity position of the torso and leg composite body

• ma double that returns the mass of the torso and leg composite body

### Warning

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

Christina Harvey

### Examples

```# refer to the vignette
library(AvInertia)

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)

```

[Package AvInertia version 0.0.1 Index]