Module pyastrobee.config.bag_properties

Cargo bag properties (including softbody info, geometry, ...)

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"""Cargo bag properties (including softbody info, geometry, ...)"""

import numpy as np

from pyastrobee.utils.transformations import make_transform_mat

from pyastrobee.utils.rotations import Rx, Ry, Rz

# Transformation matrices ("handle-to-bag"). These are defined so that the Astrobee gripper frame will be able

# to grasp the handle (z pointing along the handle, and x pointing out of the bag). "Bag frame" refers to the

# center of mass frame of the bag (what pybullet returns when you query the bag's position/orientation)

# Note: These need to be updated if the CAD changes

FRONT_HANDLE_TRANSFORM = make_transform_mat(

    Ry(-np.pi / 2) @ Rz(-np.pi / 2), [0, -0.16, 0]

)

BACK_HANDLE_TRANSFORM = make_transform_mat(Rz(np.pi / 2) @ Rx(-np.pi / 2), [0, 0.16, 0])

LEFT_HANDLE_TRANSFORM = make_transform_mat(Rz(np.pi), [-0.285, 0, 0])

RIGHT_HANDLE_TRANSFORM = make_transform_mat(np.eye(3), [0.285, 0, 0])

TOP_HANDLE_TRANSFORM = make_transform_mat(Ry(-np.pi / 2), [0, 0, 0.245])

BOTTOM_HANDLE_TRANSFORM = make_transform_mat(Ry(np.pi / 2) @ Rx(np.pi), [0, 0, -0.245])

# Softbody parameters (TODO: these may need to be refined)

# Note: setting bending/elastic stiffness to 100 seems to work well too

MASS = 1.0

BENDING_STIFFNESS = 50.0

DAMPING_STIFFNESS = 0.1

ELASTIC_STIFFNESS = 50.0

FRICTION_COEFF = 0.1

# Indices of the mesh vertices closest to the corners of the bags

# These vertices are ordered as follows:

# 0. Right back top

# 1. Right back bottom

# 2. Right front top

# 3. Right front bottom

# 4. Left back top

# 5. Left back bottom

# 6. Left front top

# 7. Left front bottom

FRONT_HANDLE_BAG_CORNERS = [289, 371, 241, 207, 330, 338, 359, 225]

RIGHT_HANDLE_BAG_CORNERS = [314, 412, 276, 216, 294, 355, 327, 243]

TOP_HANDLE_BAG_CORNERS = [296, 243, 281, 99, 237, 151, 171, 262]

FRONT_BACK_HANDLE_BAG_CORNERS = [438, 431, 319, 290, 347, 392, 311, 305]

RIGHT_LEFT_HANDLE_BAG_CORNERS = [461, 609, 410, 611, 444, 518, 395, 502]

TOP_BOTTOM_HANDLE_BAG_CORNERS = [356, 359, 333, 322, 346, 331, 214, 316]

# Dimensions of the bounding box around the main compartment of the bag (meters)

BOX_LENGTH = 0.50  # X dimension

BOX_WIDTH = 0.25  # Y dimension

BOX_HEIGHT = 0.42  # Z dimension

Variables

BACK_HANDLE_TRANSFORM

BENDING_STIFFNESS

BOTTOM_HANDLE_TRANSFORM

BOX_HEIGHT

BOX_LENGTH

BOX_WIDTH

DAMPING_STIFFNESS

ELASTIC_STIFFNESS

FRICTION_COEFF

FRONT_BACK_HANDLE_BAG_CORNERS

FRONT_HANDLE_BAG_CORNERS

FRONT_HANDLE_TRANSFORM

LEFT_HANDLE_TRANSFORM

MASS

RIGHT_HANDLE_BAG_CORNERS

RIGHT_HANDLE_TRANSFORM

RIGHT_LEFT_HANDLE_BAG_CORNERS

TOP_BOTTOM_HANDLE_BAG_CORNERS

TOP_HANDLE_BAG_CORNERS

TOP_HANDLE_TRANSFORM