機器人導航Navigation2(實體篇)

準備工作

1. 實物
2. 已經跑過一遍機器人導航Navigation2(仿真篇)
3. 本章只講大體思路實現，一般只要你仿真篇搞明白了，實體篇看看大體思路就懂怎麼實現了。
4. 本章非趙虛左教程，是自己的實現思路，僅供參考，可能趙老師有更好的辦法，不過他還沒出實體篇教程。
5. 本章用的是4輪麥克納姆輪實現的，僅供參考。

以下代碼都在下方這個github倉庫裏：

https://github.com/CyberNaviRobot/CyberRobot\_ROS2\_WS

下方的教程只有實現思路，不會放源碼，所以建議克隆一下這個倉庫，看看源碼。

導航參數參考

https://docs.nav2.org/configuration/index.html

SLAM 定位與建圖

slam_toolbox

根據上方的節點說明，我們要訂閱/scan和/tf。

一般激光雷達的說明書都會提供源碼去發佈/scan,所以這個請看你硬件的說明書。

/tf則需要我們發佈odom_frame到base_frame的轉換，我們必須使用C++代碼去動態發佈odom的座標變換。

但是這裏你需要發佈/odom,以便於知道機器人的位置和姿態，這樣才能夠夠推算出機器人在map中的位置。

確保slam toolbox各項參數沒有設置錯，特別是座標系等等，其他參數可以看着說明微調。

確保激光雷達發佈的話題是/scan。

先啓動激光雷達

再啓動urdf模型，同時發佈tf。

最後開啓slam

ros2 launch mycar_slam_slam_toolbox online_sync_launch.py use_sim_time:=false

cartographer

根據cartographer說明，我們需要/scan和/odom即可。

先打開串口接收節點，接收stm32傳過來的數據。

然後再打開里程計節點，發佈odom話題

再發布一下TF，可以直接用launch開啓robot_state_publisher和joint_state_publisher,並打開urdf模型來發布TF。

打開激光雷達的節點，發佈scan話題

等/odom,/scan和TF全發了之後，再打開cartographer建圖，然後可以檢查map的TF是否發佈。

檢查TF樹如下：

建圖如下

地圖服務

保存地圖(序列化)

mkdir ./map
ros2 run nav2_map_server map_saver_cli -f map/my_map

讀取地圖(反序列化)

ros2 launch mycar_map_server map_server.launch.py

AMCL自適應蒙特卡洛定位

首先需要地圖的數據，發佈/map話題。

其次需要激光雷達數據，即/scan話題。

然後需要座標變換消息，即/tf話題。

然後那個/initial_pose話題，是2D地圖上的初始位置，可以用rviz2發佈，也可以用C++代碼發佈。

然後需要修改一下參數：

這個是參數的官方網站：

https://docs.nav2.org/configuration/packages/configuring-amcl.html#

修改完Launch後，再修改params參數。

這裏的OmniChassis不止指全向輪底盤，而是廣義的全向輪底盤，像全向輪底盤，麥輪底盤都是全向輪底盤。當然也可以自定義底盤類型。

這個配置文件最頂上的那個use_sim_time設置爲False。

導航服務器

涉及的話題太多了，所以我們列出來了一個表：

1. 訂閱的話題

2. 發佈的話題

由於趙虛左是把官方的源碼重新寫在了WS裏，這樣對於初學者來說會比較麻煩，對於初學者來說建議使用官方寫好的bringup節點，以下是我根據官方Wiki總結出來的使用方法：（這裏選擇使用官方的bringup節點，而不是趙虛左老師的節點。）

以下是配置的nav2.launch.py文件：

import os

from ament_index_python.packages import get_package_share_directory
from launch import LaunchDescription
from launch.actions import DeclareLaunchArgument
from launch.actions import IncludeLaunchDescription
from launch.launch_description_sources import PythonLaunchDescriptionSource
from launch.substitutions import LaunchConfiguration

# from launch_ros.actions import Node

def generate_launch_description():
    navigation2_dir = get_package_share_directory('nav05_navigation2')
    nav2_bringup_dir = get_package_share_directory('nav2_bringup')

    # launch的参数的优先级比yaml的参数优先级高
    use_sim_time = LaunchConfiguration('use_sim_time', default='flase')
    map_yaml_path = LaunchConfiguration('map',default=os.path.join(navigation2_dir,'map','house.yaml'))
    nav2_param_path = LaunchConfiguration('params_file',default=os.path.join(navigation2_dir,'params','nav2.yaml'))

    return LaunchDescription([
        DeclareLaunchArgument('use_sim_time',default_value=use_sim_time,description='Use simulation (Gazebo) clock if true'),
        DeclareLaunchArgument('map',default_value=map_yaml_path,description='Full path to map file to load'),
        DeclareLaunchArgument('params_file',default_value=nav2_param_path,description='Full path to param file to load'),

        IncludeLaunchDescription(
            PythonLaunchDescriptionSource([nav2_bringup_dir,'/launch','/bringup_launch.py']),
            launch_arguments={
                'map': map_yaml_path,
                'use_sim_time': use_sim_time,
                'params_file': nav2_param_path}.items(),
        ),
    ])

以下是rviz2.launch.py：

import os

from ament_index_python.packages import get_package_share_directory
from launch import LaunchDescription
from launch.actions import DeclareLaunchArgument
from launch.substitutions import LaunchConfiguration
from launch_ros.actions import Node

def generate_launch_description():
    navigation2_dir = get_package_share_directory('nav05_navigation2')

    use_sim_time = LaunchConfiguration('use_sim_time', default='false')

    rviz_config_dir = os.path.join(navigation2_dir,'rviz','nav2.rviz')

    return LaunchDescription([
        DeclareLaunchArgument('use_sim_time',default_value=use_sim_time,description='Use simulation (Gazebo) clock if true'),

        Node(
            package='rviz2',
            executable='rviz2',
            name='rviz2',
            arguments=['-d', rviz_config_dir],
            parameters=[{'use_sim_time': use_sim_time}],
            output='screen'),
    ])

以下是nav2.yaml配置文件（差速模型+DWE局部規劃器）：

amcl:
  ros__parameters:
    use_sim_time: false
    alpha1: 0.2
    alpha2: 0.2
    alpha3: 0.2
    alpha4: 0.2
    alpha5: 0.2
    base_frame_id: "base_link"
    beam_skip_distance: 0.5
    beam_skip_error_threshold: 0.9
    beam_skip_threshold: 0.3
    do_beamskip: false
    global_frame_id: "map"
    lambda_short: 0.1
    laser_likelihood_max_dist: 2.0
    laser_max_range: 100.0
    laser_min_range: -1.0
    laser_model_type: "likelihood_field"
    max_beams: 60
    max_particles: 2000
    min_particles: 500
    odom_frame_id: "odom"
    pf_err: 0.05
    pf_z: 0.99
    recovery_alpha_fast: 0.0
    recovery_alpha_slow: 0.0
    resample_interval: 1
    robot_model_type: "nav2_amcl::DifferentialMotionModel"
    save_pose_rate: 0.5
    sigma_hit: 0.2
    tf_broadcast: true
    transform_tolerance: 1.0
    update_min_a: 0.2
    update_min_d: 0.25
    z_hit: 0.5
    z_max: 0.05
    z_rand: 0.5
    z_short: 0.05
    scan_topic: scan

amcl_map_client:
  ros__parameters:
    use_sim_time: false

amcl_rclcpp_node:
  ros__parameters:
    use_sim_time: false

bt_navigator:
  ros__parameters:
    use_sim_time: false
    global_frame: map
    robot_base_frame: base_link
    odom_topic: /odom
    bt_loop_duration: 10
    default_server_timeout: 20

    # 'default_nav_through_poses_bt_xml' and 'default_nav_to_pose_bt_xml' are use defaults:

    # nav2_bt_navigator/navigate_to_pose_w_replanning_and_recovery.xml

    # nav2_bt_navigator/navigate_through_poses_w_replanning_and_recovery.xml

    # They can be set here or via a RewrittenYaml remap from a parent launch file to Nav2.
    plugin_lib_names:
    - nav2_compute_path_to_pose_action_bt_node
    - nav2_compute_path_through_poses_action_bt_node
    - nav2_smooth_path_action_bt_node
    - nav2_follow_path_action_bt_node
    - nav2_spin_action_bt_node
    - nav2_wait_action_bt_node
    - nav2_back_up_action_bt_node
    - nav2_drive_on_heading_bt_node
    - nav2_clear_costmap_service_bt_node
    - nav2_is_stuck_condition_bt_node
    - nav2_goal_reached_condition_bt_node
    - nav2_goal_updated_condition_bt_node
    - nav2_globally_updated_goal_condition_bt_node
    - nav2_is_path_valid_condition_bt_node
    - nav2_initial_pose_received_condition_bt_node
    - nav2_reinitialize_global_localization_service_bt_node
    - nav2_rate_controller_bt_node
    - nav2_distance_controller_bt_node
    - nav2_speed_controller_bt_node
    - nav2_truncate_path_action_bt_node
    - nav2_truncate_path_local_action_bt_node
    - nav2_goal_updater_node_bt_node
    - nav2_recovery_node_bt_node
    - nav2_pipeline_sequence_bt_node
    - nav2_round_robin_node_bt_node
    - nav2_transform_available_condition_bt_node
    - nav2_time_expired_condition_bt_node
    - nav2_path_expiring_timer_condition
    - nav2_distance_traveled_condition_bt_node
    - nav2_single_trigger_bt_node
    - nav2_is_battery_low_condition_bt_node
    - nav2_navigate_through_poses_action_bt_node
    - nav2_navigate_to_pose_action_bt_node
    - nav2_remove_passed_goals_action_bt_node
    - nav2_planner_selector_bt_node
    - nav2_controller_selector_bt_node
    - nav2_goal_checker_selector_bt_node
    - nav2_controller_cancel_bt_node
    - nav2_path_longer_on_approach_bt_node
    - nav2_wait_cancel_bt_node
    - nav2_spin_cancel_bt_node
    - nav2_back_up_cancel_bt_node
    - nav2_drive_on_heading_cancel_bt_node

bt_navigator_rclcpp_node:
  ros__parameters:
    use_sim_time: false

controller_server:
  ros__parameters:
    use_sim_time: false
    controller_frequency: 20.0
    min_x_velocity_threshold: 0.001
    min_y_velocity_threshold: 0.5
    min_theta_velocity_threshold: 0.001
    failure_tolerance: 0.3
    progress_checker_plugin: "progress_checker"
    goal_checker_plugins: ["general_goal_checker"] # "precise_goal_checker"
    controller_plugins: ["FollowPath"]

    # Progress checker parameters
    progress_checker:
      plugin: "nav2_controller::SimpleProgressChecker"
      required_movement_radius: 0.5
      movement_time_allowance: 10.0

    # Goal checker parameters
    #precise_goal_checker:

    #  plugin: "nav2_controller::SimpleGoalChecker"

    #  xy_goal_tolerance: 0.25

    #  yaw_goal_tolerance: 0.25

    #  stateful: True
    general_goal_checker:
      stateful: True
      plugin: "nav2_controller::SimpleGoalChecker"
      xy_goal_tolerance: 0.25
      yaw_goal_tolerance: 0.25

    # DWB parameters
    FollowPath:
      plugin: "dwb_core::DWBLocalPlanner"
      debug_trajectory_details: True
      min_vel_x: 0.0
      min_vel_y: 0.0
      max_vel_x: 0.26
      max_vel_y: 0.0
      max_vel_theta: 1.0
      min_speed_xy: 0.0
      max_speed_xy: 0.26
      min_speed_theta: 0.0

      # Add high threshold velocity for turtlebot 3 issue.

      # https://github.com/ROBOTIS-GIT/turtlebot3_simulations/issues/75
      acc_lim_x: 2.5
      acc_lim_y: 0.0
      acc_lim_theta: 3.2
      decel_lim_x: -2.5
      decel_lim_y: 0.0
      decel_lim_theta: -3.2
      vx_samples: 20
      vy_samples: 5
      vtheta_samples: 20
      sim_time: 1.7
      linear_granularity: 0.05
      angular_granularity: 0.025
      transform_tolerance: 0.2
      xy_goal_tolerance: 0.25
      trans_stopped_velocity: 0.25
      short_circuit_trajectory_evaluation: True
      stateful: True
      critics: ["RotateToGoal", "Oscillation", "BaseObstacle", "GoalAlign", "PathAlign", "PathDist", "GoalDist"]
      BaseObstacle.scale: 0.02
      PathAlign.scale: 32.0
      PathAlign.forward_point_distance: 0.1
      GoalAlign.scale: 24.0
      GoalAlign.forward_point_distance: 0.1
      PathDist.scale: 32.0
      GoalDist.scale: 24.0
      RotateToGoal.scale: 32.0
      RotateToGoal.slowing_factor: 5.0
      RotateToGoal.lookahead_time: -1.0

controller_server_rclcpp_node:
  ros__parameters:
    use_sim_time: false

local_costmap:
  local_costmap:
    ros__parameters:
      update_frequency: 5.0
      publish_frequency: 2.0
      global_frame: odom
      robot_base_frame: base_link
      use_sim_time: false
      rolling_window: true
      width: 3
      height: 3
      resolution: 0.05
      robot_radius: 0.22
      plugins: ["static_layer", "obstacle_layer", "voxel_layer", "inflation_layer"]
      inflation_layer:
        plugin: "nav2_costmap_2d::InflationLayer"
        cost_scaling_factor: 3.0
        inflation_radius: 0.55
      obstacle_layer:
        plugin: "nav2_costmap_2d::ObstacleLayer"
        enabled: True
        observation_sources: scan
        scan:
          topic: /scan
          max_obstacle_height: 2.0
          clearing: True
          marking: True
          data_type: "LaserScan"
          raytrace_max_range: 3.0
          raytrace_min_range: 0.0
          obstacle_max_range: 2.5
          obstacle_min_range: 0.0
      voxel_layer:
        plugin: "nav2_costmap_2d::VoxelLayer"
        enabled: True
        publish_voxel_map: True
        origin_z: 0.0
        z_resolution: 0.05
        z_voxels: 16
        max_obstacle_height: 2.0
        mark_threshold: 0
        observation_sources: scan
        scan:
          topic: /scan
          max_obstacle_height: 2.0
          clearing: True
          marking: True
          data_type: "LaserScan"
          raytrace_max_range: 3.0
          raytrace_min_range: 0.0
          obstacle_max_range: 2.5
          obstacle_min_range: 0.0
      static_layer:
        plugin: "nav2_costmap_2d::StaticLayer"
        map_subscribe_transient_local: True
      always_send_full_costmap: True

  local_costmap_client:
    ros__parameters:
      use_sim_time: false
  local_costmap_rclcpp_node:
    ros__parameters:
      use_sim_time: false

global_costmap:
  global_costmap:
    ros__parameters:
      update_frequency: 1.0
      publish_frequency: 1.0
      global_frame: map
      robot_base_frame: base_link
      use_sim_time: false
      robot_radius: 0.22
      resolution: 0.05
      track_unknown_space: true
      plugins: ["static_layer", "obstacle_layer", "inflation_layer"]
      obstacle_layer:
        plugin: "nav2_costmap_2d::ObstacleLayer"
        enabled: True
        observation_sources: scan
        scan:
          topic: /scan
          max_obstacle_height: 2.0
          clearing: True
          marking: True
          data_type: "LaserScan"
          raytrace_max_range: 3.0
          raytrace_min_range: 0.0
          obstacle_max_range: 2.5
          obstacle_min_range: 0.0
      static_layer:
        plugin: "nav2_costmap_2d::StaticLayer"
        map_subscribe_transient_local: True
      inflation_layer:
        plugin: "nav2_costmap_2d::InflationLayer"
        cost_scaling_factor: 3.0
        inflation_radius: 0.55
      always_send_full_costmap: True

  global_costmap_client:
    ros__parameters:
      use_sim_time: false
  global_costmap_rclcpp_node:
    ros__parameters:
      use_sim_time: false

map_server:
  ros__parameters:
    use_sim_time: false
    yaml_filename: "house.yaml"

map_saver:
  ros__parameters:
    use_sim_time: false
    save_map_timeout: 5.0
    free_thresh_default: 0.25
    occupied_thresh_default: 0.65
    map_subscribe_transient_local: True

planner_server:
  ros__parameters:
    expected_planner_frequency: 20.0
    use_sim_time: false
    planner_plugins: ["GridBased"]
    GridBased:
      plugin: "nav2_navfn_planner/NavfnPlanner"
      tolerance: 0.5
      use_astar: false
      allow_unknown: true

planner_server_rclcpp_node:
  ros__parameters:
    use_sim_time: false

smoother_server:
  ros__parameters:
    use_sim_time: false
    smoother_plugins: ["simple_smoother"]
    simple_smoother:
      plugin: "nav2_smoother::SimpleSmoother"
      tolerance: 1.0e-10
      max_its: 1000
      do_refinement: True

behavior_server:
  ros__parameters:
    costmap_topic: local_costmap/costmap_raw
    footprint_topic: local_costmap/published_footprint
    cycle_frequency: 10.0
    behavior_plugins: ["spin", "backup", "drive_on_heading", "wait"]
    spin:
      plugin: "nav2_behaviors/Spin"
    backup:
      plugin: "nav2_behaviors/BackUp"
    drive_on_heading:
      plugin: "nav2_behaviors/DriveOnHeading"
    wait:
      plugin: "nav2_behaviors/Wait"
    global_frame: odom
    robot_base_frame: base_link
    transform_tolerance: 0.1
    use_sim_time: false
    simulate_ahead_time: 2.0
    max_rotational_vel: 1.0
    min_rotational_vel: 0.4
    rotational_acc_lim: 3.2

robot_state_publisher:
  ros__parameters:
    use_sim_time: false

waypoint_follower:
  ros__parameters:
    loop_rate: 20
    stop_on_failure: false
    waypoint_task_executor_plugin: "wait_at_waypoint"
    wait_at_waypoint:
      plugin: "nav2_waypoint_follower::WaitAtWaypoint"
      enabled: True
      waypoint_pause_duration: 200

velocity_smoother:
  ros__parameters:
    use_sim_time: false
    smoothing_frequency: 20.0
    scale_velocities: False
    feedback: "OPEN_LOOP"
    max_velocity: [0.26, 0.0, 1.0]
    min_velocity: [-0.26, 0.0, -1.0]
    max_accel: [2.5, 0.0, 3.2]
    max_decel: [-2.5, 0.0, -3.2]
    odom_topic: "odom"
    odom_duration: 0.1
    deadband_velocity: [0.0, 0.0, 0.0]
    velocity_timeout: 1.0

多車編隊