View source: R/anatomicalmassprop.R
massprop_feathers | R Documentation |
Calculate the moment of inertia of the feathers within the feather frame of reference.
massprop_feathers( m_f, l_c, l_r_cor, w_cal, r_b, d_b, rho_cor, rho_med, w_vp, w_vd, angle )
m_f |
Mass of the entire feather (kg) |
l_c |
Length of the calamus; start of vane to end of calamus(m) |
l_r_cor |
Length of rachis; tip to start of vane (m) |
w_cal |
Width (diameter) of the cortex part of the calamus (m) |
r_b |
Radius of feather barbs (m) |
d_b |
Distance between barbs (m) |
rho_cor |
Density of the cortex (kg/m^3) |
rho_med |
Density of the medullary (kg/m^3) |
w_vp |
Width of proximal (closest to body) vane (m) |
w_vd |
Width of distal (closest to wing tip) vane (m) |
angle |
Angle between calamus and the vane taken the supplement angle to the interior angle. Negative indicates the feather tip is rotated proximally relative to the start of the feather vane. |
a list that includes:
Ia 3x3 matrix representing the moment of inertia tensor of a simplified feather with the origin at the feather calamus end and within the feather frame of reference
CGa 1x3 vector representing the center of gravity position of a simplified feather with the origin at the feather calamus end and within the feather frame of reference
ma double that returns the feather mass
Parallel axis theorem does not apply between two arbitrary points. One point must be the object's center of gravity.
CAUTION: While computing the variable components of the feather the x axis is the normal of the feather.
Christina Harvey
# 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)
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