urdf_export

ROS URDF export for walker mechanisms.

URDF export for walking linkages.

Converts a Walker (hypergraph topology + dimensions) into a URDF XML string or file, suitable for visualization and simulation in ROS, Gazebo, RViz, MuJoCo, and other robotics tools.

Mapping from leggedsnake concepts to URDF:

URDF link — each edge (binary rigid bar) or hyperedge (rigid body group) becomes a URDF <link> with a cylinder visual/collision and computed inertial properties.
URDF joint — each non-ground node becomes a revolute <joint> connecting two URDF links. Ground nodes produce fixed joints attaching to the base frame. Driver nodes produce continuous (actuated) joints.
Base link — the ground/chassis frame. All ground nodes are fixed to this link.

Example:

from leggedsnake import Walker
from leggedsnake.urdf_export import to_urdf

walker = ...  # build or load a Walker
urdf_string = to_urdf(walker)
with open("walker.urdf", "w") as f:
    f.write(urdf_string)

class leggedsnake.urdf_export.URDFConfig(link_radius: float = 0.02, density: float = 1000.0, base_link_name: str = 'base_link', effort_limit: float = 1000.0, velocity_limit: float = 10.0, mesh_color: tuple[float, float, float, float] = (0.7, 0.7, 0.7, 1.0))

Bases: object

Parameters controlling URDF generation.

Variables:

link_radius (float) – Radius of cylinder geometry for each link (m).
density (float) – Material density for inertia computation (kg/m^3).
base_link_name (str) – Name of the root/chassis URDF link.
effort_limit (float) – Maximum joint effort for actuated (driver) joints (N*m).
velocity_limit (float) – Maximum joint velocity for actuated joints (rad/s).
mesh_color (tuple[float, float, float, float]) – RGBA color for visual elements.

__init__(link_radius: float = 0.02, density: float = 1000.0, base_link_name: str = 'base_link', effort_limit: float = 1000.0, velocity_limit: float = 10.0, mesh_color: tuple[float, float, float, float] = (0.7, 0.7, 0.7, 1.0)) → None

base_link_name: str = 'base_link'

density: float = 1000.0

effort_limit: float = 1000.0

link_radius: float = 0.02

mesh_color: tuple[float, float, float, float] = (0.7, 0.7, 0.7, 1.0)

velocity_limit: float = 10.0

leggedsnake.urdf_export.to_urdf(walker: Walker, config: URDFConfig | None = None) → str

Convert a Walker to a URDF XML string.

Parameters:

walker (Walker) – The walking linkage to export.
config (URDFConfig | None) – Export parameters. Uses defaults if None.

Returns:

A complete URDF XML document as a string.

Return type:

str

leggedsnake.urdf_export.to_urdf_file(walker: Walker, path: str, config: URDFConfig | None = None) → None

Write a Walker as a URDF file.

Parameters:

walker (Walker) – The walking linkage to export.
path (str) – Output file path.
config (URDFConfig | None) – Export parameters.