ROS2机器人实验报告提示05➡寻路⬅Nav2

蔚落 2022-09-16 00:27 133阅读 0赞

上一节，构建了有机器人和一些障碍物仿真元宇宙。

如何让机器人具备自主导航的能力呢？？？

--------------------

先介绍偷懒的方式：

安装turtlesim3包，然后使用官方教程即可。

*  sudo apt update
 *  sudo apt install ros-galactic-turtlebot3-gazebo ros-galactic-turtlebot3-msgs ros-galactic-turtlebot3-simulations

直接运行：

*  ros2 launch nav2\_bringup tb3\_simulation\_launch.py

查看是否报错！

如果打不开，多尝试几次！

> export TURTLEBOT3\_MODEL=waffle  
> export GAZEBO\_MODEL\_PATH=$GAZEBO\_MODEL\_PATH:/opt/ros/galactic/share/turtlebot3\_gazebo/models

如上环境一定要争取配置，推荐添加到bash文件中。

![watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBAemhhbmdyZWxheQ_size_20_color_FFFFFF_t_70_g_se_x_16][]

![watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBAemhhbmdyZWxheQ_size_20_color_FFFFFF_t_70_g_se_x_16 1][]

![watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBAemhhbmdyZWxheQ_size_20_color_FFFFFF_t_70_g_se_x_16 2][]

![watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBAemhhbmdyZWxheQ_size_20_color_FFFFFF_t_70_g_se_x_16 3][]

![watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBAemhhbmdyZWxheQ_size_20_color_FFFFFF_t_70_g_se_x_16 4][]

![watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBAemhhbmdyZWxheQ_size_20_color_FFFFFF_t_70_g_se_x_16 5][]

![watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBAemhhbmdyZWxheQ_size_20_color_FFFFFF_t_70_g_se_x_16 6][]

更多内容参考博客相关章节或观看钉钉直播课回放。

*  [ROS2机器人个人教程博客汇总（2021共6套）][ROS2_2021_6]

--------------------

思考题：

对比ros2 launch nav2\_bringup tb3\_simulation\_launch.py和ros2 launch sam\_bot\_description display.launch.py。

实现机器人自动导航，需要哪些功能包，如何实现。

tb3\_simulation\_launch.py

# Copyright (c) 2018 Intel Corporation
    #
    # Licensed under the Apache License, Version 2.0 (the "License");
    # you may not use this file except in compliance with the License.
    # You may obtain a copy of the License at
    #
    #     http://www.apache.org/licenses/LICENSE-2.0
    #
    # Unless required by applicable law or agreed to in writing, software
    # distributed under the License is distributed on an "AS IS" BASIS,
    # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    # See the License for the specific language governing permissions and
    # limitations under the License.
    
    """This is all-in-one launch script intended for use by nav2 developers."""
    
    import os
    
    from ament_index_python.packages import get_package_share_directory
    
    from launch import LaunchDescription
    from launch.actions import DeclareLaunchArgument, ExecuteProcess, IncludeLaunchDescription
    from launch.conditions import IfCondition
    from launch.launch_description_sources import PythonLaunchDescriptionSource
    from launch.substitutions import LaunchConfiguration, PythonExpression
    from launch_ros.actions import Node
    
    
    def generate_launch_description():
        # Get the launch directory
        bringup_dir = get_package_share_directory('nav2_bringup')
        launch_dir = os.path.join(bringup_dir, 'launch')
    
        # Create the launch configuration variables
        slam = LaunchConfiguration('slam')
        namespace = LaunchConfiguration('namespace')
        use_namespace = LaunchConfiguration('use_namespace')
        map_yaml_file = LaunchConfiguration('map')
        use_sim_time = LaunchConfiguration('use_sim_time')
        params_file = LaunchConfiguration('params_file')
        autostart = LaunchConfiguration('autostart')
    
        # Launch configuration variables specific to simulation
        rviz_config_file = LaunchConfiguration('rviz_config_file')
        use_simulator = LaunchConfiguration('use_simulator')
        use_robot_state_pub = LaunchConfiguration('use_robot_state_pub')
        use_rviz = LaunchConfiguration('use_rviz')
        headless = LaunchConfiguration('headless')
        world = LaunchConfiguration('world')
    
        # Map fully qualified names to relative ones so the node's namespace can be prepended.
        # In case of the transforms (tf), currently, there doesn't seem to be a better alternative
        # https://github.com/ros/geometry2/issues/32
        # https://github.com/ros/robot_state_publisher/pull/30
        # TODO(orduno) Substitute with `PushNodeRemapping`
        #              https://github.com/ros2/launch_ros/issues/56
        remappings = [('/tf', 'tf'),
                      ('/tf_static', 'tf_static')]
    
        # Declare the launch arguments
        declare_namespace_cmd = DeclareLaunchArgument(
            'namespace',
            default_value='',
            description='Top-level namespace')
    
        declare_use_namespace_cmd = DeclareLaunchArgument(
            'use_namespace',
            default_value='false',
            description='Whether to apply a namespace to the navigation stack')
    
        declare_slam_cmd = DeclareLaunchArgument(
            'slam',
            default_value='False',
            description='Whether run a SLAM')
    
        declare_map_yaml_cmd = DeclareLaunchArgument(
            'map',
            default_value=os.path.join(
                bringup_dir, 'maps', 'turtlebot3_world.yaml'),
            description='Full path to map file to load')
    
        declare_use_sim_time_cmd = DeclareLaunchArgument(
            'use_sim_time',
            default_value='true',
            description='Use simulation (Gazebo) clock if true')
    
        declare_params_file_cmd = DeclareLaunchArgument(
            'params_file',
            default_value=os.path.join(bringup_dir, 'params', 'nav2_params.yaml'),
            description='Full path to the ROS2 parameters file to use for all launched nodes')
    
        declare_autostart_cmd = DeclareLaunchArgument(
            'autostart', default_value='true',
            description='Automatically startup the nav2 stack')
    
        declare_rviz_config_file_cmd = DeclareLaunchArgument(
            'rviz_config_file',
            default_value=os.path.join(
                bringup_dir, 'rviz', 'nav2_default_view.rviz'),
            description='Full path to the RVIZ config file to use')
    
        declare_use_simulator_cmd = DeclareLaunchArgument(
            'use_simulator',
            default_value='True',
            description='Whether to start the simulator')
    
        declare_use_robot_state_pub_cmd = DeclareLaunchArgument(
            'use_robot_state_pub',
            default_value='True',
            description='Whether to start the robot state publisher')
    
        declare_use_rviz_cmd = DeclareLaunchArgument(
            'use_rviz',
            default_value='True',
            description='Whether to start RVIZ')
    
        declare_simulator_cmd = DeclareLaunchArgument(
            'headless',
            default_value='False',
            description='Whether to execute gzclient)')
    
        declare_world_cmd = DeclareLaunchArgument(
            'world',
            # TODO(orduno) Switch back once ROS argument passing has been fixed upstream
            #              https://github.com/ROBOTIS-GIT/turtlebot3_simulations/issues/91
            # default_value=os.path.join(get_package_share_directory('turtlebot3_gazebo'),
            # worlds/turtlebot3_worlds/waffle.model')
            default_value=os.path.join(bringup_dir, 'worlds', 'waffle.model'),
            description='Full path to world model file to load')
    
        # Specify the actions
        start_gazebo_server_cmd = ExecuteProcess(
            condition=IfCondition(use_simulator),
            cmd=['gzserver', '-s', 'libgazebo_ros_init.so', world],
            cwd=[launch_dir], output='screen')
    
        start_gazebo_client_cmd = ExecuteProcess(
            condition=IfCondition(PythonExpression(
                [use_simulator, ' and not ', headless])),
            cmd=['gzclient'],
            cwd=[launch_dir], output='screen')
    
        urdf = os.path.join(bringup_dir, 'urdf', 'turtlebot3_waffle.urdf')
    
        start_robot_state_publisher_cmd = Node(
            condition=IfCondition(use_robot_state_pub),
            package='robot_state_publisher',
            executable='robot_state_publisher',
            name='robot_state_publisher',
            namespace=namespace,
            output='screen',
            parameters=[{'use_sim_time': use_sim_time}],
            remappings=remappings,
            arguments=[urdf])
    
        rviz_cmd = IncludeLaunchDescription(
            PythonLaunchDescriptionSource(
                os.path.join(launch_dir, 'rviz_launch.py')),
            condition=IfCondition(use_rviz),
            launch_arguments={'namespace': '',
                              'use_namespace': 'False',
                              'rviz_config': rviz_config_file}.items())
    
        bringup_cmd = IncludeLaunchDescription(
            PythonLaunchDescriptionSource(
                os.path.join(launch_dir, 'bringup_launch.py')),
            launch_arguments={'namespace': namespace,
                              'use_namespace': use_namespace,
                              'slam': slam,
                              'map': map_yaml_file,
                              'use_sim_time': use_sim_time,
                              'params_file': params_file,
                              'autostart': autostart}.items())
    
        # Create the launch description and populate
        ld = LaunchDescription()
    
        # Declare the launch options
        ld.add_action(declare_namespace_cmd)
        ld.add_action(declare_use_namespace_cmd)
        ld.add_action(declare_slam_cmd)
        ld.add_action(declare_map_yaml_cmd)
        ld.add_action(declare_use_sim_time_cmd)
        ld.add_action(declare_params_file_cmd)
        ld.add_action(declare_autostart_cmd)
    
        ld.add_action(declare_rviz_config_file_cmd)
        ld.add_action(declare_use_simulator_cmd)
        ld.add_action(declare_use_robot_state_pub_cmd)
        ld.add_action(declare_use_rviz_cmd)
        ld.add_action(declare_simulator_cmd)
        ld.add_action(declare_world_cmd)
    
        # Add any conditioned actions
        ld.add_action(start_gazebo_server_cmd)
        ld.add_action(start_gazebo_client_cmd)
    
        # Add the actions to launch all of the navigation nodes
        ld.add_action(start_robot_state_publisher_cmd)
        ld.add_action(rviz_cmd)
        ld.add_action(bringup_cmd)
    
        return ld

sam\_bot\_description display.launch.py

import launch
    from launch.substitutions import Command, LaunchConfiguration
    import launch_ros
    import os
    
    def generate_launch_description():
        pkg_share = launch_ros.substitutions.FindPackageShare(package='sam_bot_description').find('sam_bot_description')
        default_model_path = os.path.join(pkg_share, 'src/description/sam_bot_description.urdf')
        default_rviz_config_path = os.path.join(pkg_share, 'rviz/urdf_config.rviz')
        world_path=os.path.join(pkg_share, 'world/my_world.sdf')
        
        robot_state_publisher_node = launch_ros.actions.Node(
            package='robot_state_publisher',
            executable='robot_state_publisher',
            parameters=[{'robot_description': Command(['xacro ', LaunchConfiguration('model')])}]
        )
        joint_state_publisher_node = launch_ros.actions.Node(
            package='joint_state_publisher',
            executable='joint_state_publisher',
            name='joint_state_publisher',
            condition=launch.conditions.UnlessCondition(LaunchConfiguration('gui'))
        )
        rviz_node = launch_ros.actions.Node(
            package='rviz2',
            executable='rviz2',
            name='rviz2',
            output='screen',
            arguments=['-d', LaunchConfiguration('rvizconfig')],
        )
        spawn_entity = launch_ros.actions.Node(
        	package='gazebo_ros', 
        	executable='spawn_entity.py',
            arguments=['-entity', 'sam_bot', '-topic', 'robot_description'],
            output='screen'
        )
        robot_localization_node = launch_ros.actions.Node(
             package='robot_localization',
             executable='ekf_node',
             name='ekf_filter_node',
             output='screen',
             parameters=[os.path.join(pkg_share, 'config/ekf.yaml'), {'use_sim_time': LaunchConfiguration('use_sim_time')}]
        )
    
        return launch.LaunchDescription([
            launch.actions.DeclareLaunchArgument(name='gui', default_value='True',
                                                description='Flag to enable joint_state_publisher_gui'),
            launch.actions.DeclareLaunchArgument(name='model', default_value=default_model_path,
                                                description='Absolute path to robot urdf file'),
            launch.actions.DeclareLaunchArgument(name='rvizconfig', default_value=default_rviz_config_path,
                                                description='Absolute path to rviz config file'),
            launch.actions.DeclareLaunchArgument(name='use_sim_time', default_value='True',
                                                description='Flag to enable use_sim_time'),
            launch.actions.ExecuteProcess(cmd=['gazebo', '--verbose', '-s', 'libgazebo_ros_factory.so', world_path], output='screen'),
    
            joint_state_publisher_node,
            robot_state_publisher_node,
            spawn_entity,
            robot_localization_node,
            rviz_node
        ])

能否修改sam\_bot\_description display.launch.py，是其不仅具备SLAM还具备导航功能呢？

?\_?

^\_^

--------------------

[watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBAemhhbmdyZWxheQ_size_20_color_FFFFFF_t_70_g_se_x_16]: /images/20220828/e165a27cf2ee4900b29114032b10b436.png
[watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBAemhhbmdyZWxheQ_size_20_color_FFFFFF_t_70_g_se_x_16 1]: /images/20220828/29f25434dccf4e8e81f7023524dd228b.png
[watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBAemhhbmdyZWxheQ_size_20_color_FFFFFF_t_70_g_se_x_16 2]: /images/20220828/6ed02ff6de254c4c879cf82889965037.png
[watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBAemhhbmdyZWxheQ_size_20_color_FFFFFF_t_70_g_se_x_16 3]: /images/20220828/6e0e5180469247179cdf5cd375f950fd.png
[watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBAemhhbmdyZWxheQ_size_20_color_FFFFFF_t_70_g_se_x_16 4]: /images/20220828/9e84051edc7b4576b197ef3e7e3254ea.png
[watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBAemhhbmdyZWxheQ_size_20_color_FFFFFF_t_70_g_se_x_16 5]: /images/20220828/40a53fc3818d4a99bb7a7676964d64a1.png
[watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBAemhhbmdyZWxheQ_size_20_color_FFFFFF_t_70_g_se_x_16 6]: /images/20220828/028001e0859a4323a829e5c5c11a230f.png
[ROS2_2021_6]: https://blog.csdn.net/ZhangRelay/article/details/120062413?spm=1001.2014.3001.5502