Rviz 同时显示多个独立 URDF！解决双机械臂+底盘等场景（球体+方块实例演示）

视频讲解：

仓库地址：GitHub - LitchiCheng/ros2_package

有小伙伴留言说想看下同时使用多个独立的urdf如何配置，实际上这个场景是很常见的，比如双机械臂，机械臂加底盘，机械臂加双足等等，都是多个独立的urdf文件构成，这个时候同时在Rivz中显示多个模型就很有用了，今天我们以一个球体的urdf和一个方块的urdf为例，介绍下如何搭建。

首先新建一个package

ros2 pkg create --build-type ament_cmake multi_urdf_display --dependencies rclcpp robot_state_publisher tf2_ros

新建一个urdf文件夹

在urdf中新建cube.urdf

<?xml version="1.0"?>
<robot name="cube">
    <link name="base_link">
        <visual>
            <geometry>
                <box size="1 1 1"/>
            </geometry>
            <material name="blue">
                <color rgba="0 0 1 1"/>
            </material>
        </visual>
        <collision>
            <geometry>
                <box size="1 1 1"/>
            </geometry>
        </collision>
        <inertial>
            <origin xyz="0 0 0" rpy="0 0 0"/>
            <mass value="1"/>
            <inertia ixx="1" ixy="0" ixz="0" iyy="1" iyz="0" izz="1"/>
        </inertial>
    </link>
</robot>

再新建一个sphere.urdf

<?xml version="1.0"?>
<robot name="sphere">
    <link name="base_link">
        <visual>
            <geometry>
                <sphere radius="0.5"/>
            </geometry>
            <material name="red">
                <color rgba="1 0 0 1"/>
            </material>
        </visual>
        <collision>
            <geometry>
                <sphere radius="0.5"/>
            </geometry>
        </collision>
        <inertial>
            <origin xyz="0 0 0" rpy="0 0 0"/>
            <mass value="1"/>
            <inertia ixx="0.1" ixy="0" ixz="0" iyy="0.1" iyz="0" izz="0.1"/>
        </inertial>
    </link>
</robot>

创建一个launch文件夹，新建一个display_multi_urdf.launch.py

import os
from launch import LaunchDescription
from launch_ros.actions import Node
from ament_index_python.packages import get_package_share_directory

def load_urdf(pkg_name, urdf_file):
    pkg_path = get_package_share_directory(pkg_name)
    urdf_path = os.path.join(pkg_path, 'urdf', urdf_file)
    with open(urdf_path, 'r') as f:
        return f.read()

def generate_launch_description():
    robot_desc1 = load_urdf('multi_urdf_display', 'cube.urdf')
    robot_desc2 = load_urdf('multi_urdf_display', 'sphere.urdf')

    return LaunchDescription([
        Node(
            package='robot_state_publisher',
            executable='robot_state_publisher',
            name='cube_state_pub',
            namespace='cube',
            parameters=[{'robot_description': robot_desc1}],              
        ),
        Node(
            package='robot_state_publisher',
            executable='robot_state_publisher',
            name='sphere_state_pub',
            namespace='sphere',
            parameters=[{'robot_description': robot_desc2}],
            
        ),
        Node(
            package='tf2_ros',
            executable='static_transform_publisher',
            namespace='cube',
            arguments=['0', '0', '0', '0', '0', '0', 'world', 'cube/base_link'],
           
        ),
        Node(
            package='tf2_ros',
            executable='static_transform_publisher',
            namespace='sphere',
            arguments=['2', '0', '0', '0', '0', '0', 'world', 'sphere/base_link'],
            
        ),
        Node(
            package='rviz2',
            executable='rviz2',
            name='rviz2',
            arguments=['-d', os.path.join(
                get_package_share_directory('multi_urdf_display'),
                'rviz','display_multi_urdf.rviz')]
        )
    ])

创建一个rviz文件夹，新建一个display_multi_urdf.rviz

<?xml version="1.0" ?>
<rviz config_version="1.12">
  <VisualizationManager>
    <GlobalOptions>
      <FixedFrame value="world"/>
      <FrameRate value="30"/>
    </GlobalOptions>
    <Display>
      <Class value="rviz/RobotModel"/>
      <Name value="Cube"/>
      <Enabled value="true"/>
      <RobotDescriptionTopic value="/cube/robot_description"/>
      <TFPrefix value="cube"/>
    </Display>
    <Display>
      <Class value="rviz/RobotModel"/>
      <Name value="Sphere"/>
      <Enabled value="true"/>
      <RobotDescriptionTopic value="/sphere/robot_description"/>
      <TFPrefix value="sphere"/>
    </Display>
  </VisualizationManager>
</rviz>

增加如下到CMakeLists.txt文件

install(DIRECTORY launch urdf rviz
  DESTINATION share/${PROJECT_NAME})

编译运行

colcon build --packages-select multi_urdf_display
source install/setup.bash
ros2 launch multi_urdf_display display_multi_urdf.launch.py

添加pannel Displays后

添加两个RobotModel后，需要配置Topic以及TF Prefix，可以看到两个URDF都显示在了Rviz中

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