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XACRO

Xacro (XML Macros) Xacro is an XML macro language. With xacro, you can construct shorter and more readable XML files by using macros that expand to larger XML expressions. more

Install ROS support

1
sudo apt install ros-humble-xacro

Usage

cli

1
xacro hello.urdf.xacro > hello.urdf

from launch file

load xacro and spawn in gazebo classic
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import os

from ament_index_python.packages import get_package_share_directory


from launch import LaunchDescription
from launch.actions import IncludeLaunchDescription
from launch.launch_description_sources import PythonLaunchDescriptionSource
from launch.substitutions import LaunchConfiguration, Command
from launch_ros.actions import Node

PKG_DESCRIPTION = "gz_tutorial_description"

def generate_launch_description():
    pkg_path = os.path.join(get_package_share_directory(PKG_DESCRIPTION))
    xacro_file = os.path.join(pkg_path,'urdf','my_robot.urdf.xacro')
    # robot_description_config = xacro.process_file(xacro_file).toxml()
    robot_description_config = Command(['xacro ', xacro_file])

    # Create a robot_state_publisher node
    params = {'robot_description': robot_description_config, 'use_sim_time': True}
    node_robot_state_publisher = Node(
        package='robot_state_publisher',
        executable='robot_state_publisher',
        output='screen',
        parameters=[params]
    )

    gazebo = IncludeLaunchDescription(
                PythonLaunchDescriptionSource([os.path.join(
                    get_package_share_directory('gazebo_ros'), 'launch', 'gazebo.launch.py')])
    )

    spawn_entity = Node(package='gazebo_ros', executable='spawn_entity.py',
                        arguments=['-topic', 'robot_description',
                                   '-entity', 'my_bot'],
                        output='screen')

    return LaunchDescription([
        node_robot_state_publisher,
        gazebo,
        spawn_entity
    ])

XACRO terms