bb87928bce
Upstream: https://github.com/Rhoban/onshape-to-robot Upstream-Commit: 80e710700aac9573a2230f74f7ce9e094833a0bc Upstream-Branch: master
327 lines
12 KiB
Python
327 lines
12 KiB
Python
from __future__ import annotations
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import numpy as np
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import os
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from .message import warning
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from .robot import Robot, Link, Part, Joint
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from .config import Config
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from .geometry import Box, Cylinder, Sphere, Shape, Mesh
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from .exporter import Exporter
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from .exporter_utils import xml_escape, rotation_matrix_to_rpy
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class ExporterURDF(Exporter):
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def __init__(self, config: Config | None = None):
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super().__init__()
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self.config: Config = config
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self.ext: str = "urdf"
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self.no_dynamics: bool = False
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self.package_name: str = ""
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self.additional_xml: str = ""
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self.set_zero_mass_to_fixed: bool = False
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if config is not None:
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self.no_dynamics = config.no_dynamics
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self.package_name: str = config.get("package_name", "")
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self.set_zero_mass_to_fixed: bool = config.get(
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"set_zero_mass_to_fixed", False
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)
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additional_xml_file = config.get("additional_xml", None, required=False)
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if isinstance(additional_xml_file, str):
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self.add_additional_xml(additional_xml_file)
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elif isinstance(additional_xml_file, list):
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for filename in additional_xml_file:
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self.add_additional_xml(filename)
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def add_additional_xml(self, xml_file: str):
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self.additional_xml += f"<!-- Additional {xml_file} -->"
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with open(self.config.output_directory + "/" + xml_file, "r") as file:
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self.additional_xml += file.read()
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def append(self, line: str):
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self.xml += line
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def build(self, robot: Robot):
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self.xml = ""
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self.append('<?xml version="1.0" ?>')
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self.append("<!-- Generated using onshape-to-robot -->")
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if self.config:
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self.append(f"<!-- Onshape {self.config.printable_version()} -->")
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self.append(f'<robot name="{robot.name}">')
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if len(robot.base_links) > 1:
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print(
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warning(
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"WARNING: Multiple base links detected, which is not supported by URDF."
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)
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)
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print(warning("Only the first base link will be considered."))
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if len(robot.base_links) > 0:
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self.add_link(robot, robot.base_links[0])
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if self.additional_xml:
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self.append(self.additional_xml)
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self.append("</robot>")
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return self.xml
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def add_inertial(
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self, mass: float, com: np.ndarray, inertia: np.ndarray, fixed: str = False
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):
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# Unless "no_dynamics" is set, we make sure that mass and inertia
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# are not zero
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if not self.no_dynamics:
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mass = max(1e-9, mass)
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inertia[0, 0] = max(1e-9, inertia[0, 0])
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inertia[1, 1] = max(1e-9, inertia[1, 1])
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inertia[2, 2] = max(1e-9, inertia[2, 2])
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if fixed and self.set_zero_mass_to_fixed:
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# To mark an object as fixed in the world, sets its dynamics to zero
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mass = 0
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com = np.zeros(3)
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inertia = np.zeros((3, 3))
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self.append("<inertial>")
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self.append(
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'<origin xyz="%g %g %g" rpy="0 0 0"/>'
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% self.config.round(
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(
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com[0],
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com[1],
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com[2],
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)
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)
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)
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self.append('<mass value="%g" />' % self.config.round(mass))
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self.append(
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'<inertia ixx="%g" ixy="%g" ixz="%g" iyy="%g" iyz="%g" izz="%g" />'
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% self.config.round(
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(
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inertia[0, 0],
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inertia[0, 1],
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inertia[0, 2],
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inertia[1, 1],
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inertia[1, 2],
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inertia[2, 2],
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)
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)
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)
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self.append("</inertial>")
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def add_mesh(self, part: Part, node: str, T_world_link: np.ndarray, mesh: Mesh):
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"""
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Add a mesh node (e.g. STL) to the URDF file
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"""
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self.append(f"<{node}>")
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T_link_part = np.linalg.inv(T_world_link) @ part.T_world_part
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self.append(self.origin(T_link_part))
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mesh_file = mesh.filename
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if self.package_name:
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mesh_file = self.package_name + "/" + mesh_file
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self.append("<geometry>")
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self.append(f'<mesh filename="package://{xml_escape(mesh_file)}" />')
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self.append("</geometry>")
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if node == "visual":
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material_name = f"{part.name}_material"
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self.append(f'<material name="{xml_escape(material_name)}">')
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self.append(
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'<color rgba="%g %g %g %g"/>'
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% self.config.round(
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(mesh.color[0], mesh.color[1], mesh.color[2], mesh.color[3])
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)
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)
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self.append("</material>")
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# Apply properties based on node type (visual or collision)
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properties = mesh.visual_properties if node == "visual" else mesh.collision_properties
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for key, value in properties.items():
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self.append(f'<{key}>{xml_escape(str(value))}</{key}>')
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self.append(f"</{node}>")
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def add_shape(self, part: Part, node: str, T_world_link: np.ndarray, shape: Shape):
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"""
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Add shapes (box, sphere and cylinder) nodes to the URDF.
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"""
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self.append(f"<{node}>")
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T_link_shape = (
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np.linalg.inv(T_world_link) @ part.T_world_part @ shape.T_part_shape
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)
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self.append(self.origin(T_link_shape))
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self.append("<geometry>")
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if isinstance(shape, Box):
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self.append(
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'<box size="%g %g %g" />' % self.config.round(tuple(shape.size))
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)
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elif isinstance(shape, Cylinder):
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self.append(
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'<cylinder length="%g" radius="%g" />'
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% self.config.round((shape.length, shape.radius))
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)
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elif isinstance(shape, Sphere):
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self.append('<sphere radius="%g" />' % self.config.round((shape.radius,)))
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self.append("</geometry>")
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if node == "visual":
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material_name = f"{part.name}_material"
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self.append(f'<material name="{xml_escape(material_name)}">')
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self.append(
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'<color rgba="%g %g %g %g"/>'
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% self.config.round(
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(shape.color[0], shape.color[1], shape.color[2], shape.color[3])
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)
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)
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self.append("</material>")
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# Apply properties based on node type (visual or collision)
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properties = shape.visual_properties if node == "visual" else shape.collision_properties
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for key, value in properties.items():
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self.append(f'<{key}>{xml_escape(str(value))}</{key}>')
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self.append(f"</{node}>")
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def add_geometries(self, part: Part, T_world_link: np.ndarray):
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"""
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Add a part geometries
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"""
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for shape in part.shapes:
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if shape.visual:
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self.add_shape(part, "visual", T_world_link, shape)
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if shape.collision:
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self.add_shape(part, "collision", T_world_link, shape)
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for mesh in part.meshes:
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if mesh.visual:
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self.add_mesh(part, "visual", T_world_link, mesh)
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if mesh.collision:
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self.add_mesh(part, "collision", T_world_link, mesh)
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def add_joint(self, joint: Joint, T_world_link: np.ndarray):
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self.append(f"<!-- Joint from {joint.parent.name} to {joint.child.name} -->")
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joint_type = joint.properties.get("type", joint.joint_type)
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self.append(f'<joint name="{joint.name}" type="{joint_type}">')
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T_link_joint = np.linalg.inv(T_world_link) @ joint.T_world_joint
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self.append(self.origin(T_link_joint))
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self.append(f'<parent link="{joint.parent.name}" />')
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self.append(f'<child link="{joint.child.name}" />')
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self.append('<axis xyz="%g %g %g"/>' % self.config.round(tuple(joint.axis)))
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limits = ""
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if "max_effort" in joint.properties:
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limits += 'effort="%g" ' % self.config.round(joint.properties["max_effort"])
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else:
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limits += 'effort="10" '
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if "max_velocity" in joint.properties:
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limits += 'velocity="%g" ' % self.config.round(
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joint.properties["max_velocity"]
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)
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else:
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limits += 'velocity="10" '
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joint_limits = joint.properties.get("limits", joint.limits)
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if joint_limits is not None:
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limits += 'lower="%g" upper="%g" ' % self.config.round(
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(joint_limits[0], joint_limits[1])
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)
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elif joint_type == "revolute":
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limits += f'lower="{-np.pi}" upper="{np.pi}" '
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elif joint_type == "prismatic":
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limits += 'lower="-1" upper="1" '
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if limits:
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self.append(f"<limit {limits}/>")
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if "friction" in joint.properties:
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self.append(
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f'<joint_properties friction="{joint.properties["friction"]}"/>'
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)
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if joint.relation is not None:
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self.append(
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f'<mimic joint="{joint.relation.source_joint}" multiplier="{joint.relation.ratio}" />'
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)
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self.append("</joint>")
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def add_frame(
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self,
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link: Link,
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frame: str,
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T_world_link: np.ndarray,
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T_world_frame: np.ndarray,
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):
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self.append(f"<!-- Frame {frame} (dummy link + fixed joint) -->")
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T_link_frame = np.linalg.inv(T_world_link) @ T_world_frame
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# Adding a dummy link to the assembly
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self.append(f'<link name="{frame}">')
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self.append(self.origin(np.eye(4)))
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self.append("<inertial>")
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self.append('<origin xyz="0 0 0" rpy="0 0 0" />')
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if self.no_dynamics:
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self.append('<mass value="0" />')
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else:
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self.append('<mass value="1e-9" />')
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self.append('<inertia ixx="0" ixy="0" ixz="0" iyy="0" iyz="0" izz="0" />')
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self.append("</inertial>")
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self.append("</link>")
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# Attaching this dummy link to the parent frame using a fixed joint
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self.append(f'<joint name="{frame}_frame" type="fixed">')
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self.append(self.origin(T_link_frame))
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self.append(f'<parent link="{link.name}" />')
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self.append(f'<child link="{frame}" />')
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self.append('<axis xyz="0 0 0"/>')
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self.append("</joint>")
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def add_link(self, robot: Robot, link: Link, T_world_link: np.ndarray = np.eye(4)):
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"""
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Adds a link recursively to the URDF file
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"""
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self.append(f"<!-- Link {link.name} -->")
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self.append(f'<link name="{link.name}">')
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# Adding inertial properties
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mass, com, inertia = link.get_dynamics(T_world_link)
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self.add_inertial(mass, com, inertia, link.fixed)
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# Adding geometry objects
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for part in link.parts:
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self.append(f"<!-- Part {part.name} -->")
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self.add_geometries(part, T_world_link)
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self.append("</link>")
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# Adding frames attached to current link
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for frame, T_world_frame in link.frames.items():
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self.add_frame(link, frame, T_world_link, T_world_frame)
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# Adding joints and children links
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for joint in robot.get_link_joints(link):
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self.add_link(robot, joint.child, joint.T_world_joint)
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self.add_joint(joint, T_world_link)
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def origin(self, matrix: np.ndarray):
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"""
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Transforms a transformation matrix into a URDF origin tag
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"""
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urdf = '<origin xyz="%g %g %g" rpy="%g %g %g" />'
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return urdf % self.config.round(
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(*matrix[:3, 3], *rotation_matrix_to_rpy(matrix))
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)
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