Question about part 3 Ros2 Nav in 5 Days

ghassan11 · March 20, 2024, 9:33pm

Hi everyone,
I am lost in The Real project of the course Ros2 Navigation in 5 days i did not understand 2 points the first :

In the part 2 (Localization):

Now here we have to do 2 things firstly add spots manually in a file called spots.yaml and then we will create the service that do it automatically just we call it on the point and it will save it in a file called spots.txt correct ?
so for the manually .yaml but the one with the code will be a .txt ? this is my first question ?

Second one is about part 3 (Pathplanner):

In this i should create the launch file that we did it in the course on part 4 but the thing that confused me is the project_params.yaml like i don’t know what’s that file and i did not hear about it in the full course like what is this file about ?

I hope anyone can help me,

Best Regards,

Ghassan

girishkumar.kannan · March 21, 2024, 7:21am

Hi @ghassan11 ,

As far as I remember when I worked on this project, I did not create a spots.txt file.
I directly saved the spots as x, y, theta values, directly in a spots.yaml file.
A yaml file is easier to work with than a txt file. You can use the yaml libraries to unwrap saved data, unlike in text file where you have to process data yourself.
You don’t have to create a project_params.yaml file (the instructions are/were a little bit misleading). It is better to instead create the 5 config files : 4 yaml files for planner, controller, recoveries, bt_navigator and 1 xml file for behavior.

I hope this resolves your confusion.

Regards,
Girish

ghassan11 · March 21, 2024, 6:16pm

Hi @girishkumar.kannan

Thank you for your reply now i understood it well
but i got an error in part 3(pathplanning)

I did as u told me i took the 4 config files and the .xml from the course and then i made the infos based on my package and path and i made the launch when i run it i get this error:

girishkumar.kannan · March 22, 2024, 5:51am

Hi @ghassan11 ,

The error report seems to be quite clear, it says:

Caught exception when trying to load file of format [py]: 
"package 'path_planner_server' not found, searching [...paths...]"

I think you have copy pasted the config files directly from your course packages directly into the rosject.

From your command, I see that you are trying to launch path_planning.launch.py file from the project_path_planning package.
It is clear that one of your launch files or config files is still having reference to your course package names and you have forgotten to replace the package name reference in those files.

Please recheck your config files, launch files and CMakeLists.txt or setup.py file to see if there are any incorrect package name references and correct them. That should fix this problem!

Regards,
Girish

ghassan11 · March 22, 2024, 11:25am

Hi @girishkumar.kannan

I checked everything and its all correct
i dont know where is the problem

these are the files paths :

config :

behavior.xml:

<!--
  This Behavior Tree replans the global path periodically at 1 Hz, and has
  recovery actions. Obtained from the official Nav2 package
-->
<root main_tree_to_execute="MainTree">
  <BehaviorTree ID="MainTree">
    <RecoveryNode number_of_retries="6" name="NavigateRecovery">
      <PipelineSequence name="NavigateWithReplanning">
        <RateController hz="1.0">
          <RecoveryNode number_of_retries="1" name="ComputePathToPose">
            <ComputePathToPose goal="{goal}" path="{path}" planner_id="GridBased"/>
            <ClearEntireCostmap service_name="global_costmap/clear_entirely_global_costmap"/>
          </RecoveryNode>
        </RateController>
        <RecoveryNode number_of_retries="1" name="FollowPath">
          <FollowPath path="{path}" controller_id="FollowPath"/>
          <ClearEntireCostmap service_name="local_costmap/clear_entirely_local_costmap"/>
        </RecoveryNode>
      </PipelineSequence>
      <SequenceStar name="RecoveryActions">
        <ClearEntireCostmap service_name="local_costmap/clear_entirely_local_costmap"/>
        <ClearEntireCostmap service_name="global_costmap/clear_entirely_global_costmap"/>
        <Spin spin_dist="1.57"/>
        <Wait wait_duration="5"/>
      </SequenceStar>
    </RecoveryNode>
  </BehaviorTree>
</root>

bt_navigator.yaml:

bt_navigator:
  ros__parameters:
    use_sim_time: True
    global_frame: map
    robot_base_frame: base_link
    odom_topic: /odom
    bt_loop_duration: 10
    default_server_timeout: 20
    default_nav_to_pose_bt_xml: "/home/user/ros2_ws/src/project_path_planning/config/behavior.xml"
    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_goal_updated_controller_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

controller.yaml:

controller_server:
  ros__parameters:
    use_sim_time: True
    controller_frequency: 10.0
    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"] 
    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
    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
      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

planner_server.yaml:

planner_server:
  ros__parameters:
    expected_planner_frequency: 10.0
    use_sim_time: True
    planner_plugins: ["GridBased"]
    GridBased:
      plugin: "nav2_navfn_planner/NavfnPlanner"
      tolerance: 0.5
      use_astar: false
      allow_unknown: true

recovery.yaml:

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

launch file:

path_planning.launch.py:

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

def generate_launch_description():

    controller_yaml = os.path.join(get_package_share_directory('path_planner_server'), 'config', 'controller.yaml')
    bt_navigator_yaml = os.path.join(get_package_share_directory('path_planner_server'), 'config', 'bt_navigator.yaml')
    planner_yaml = os.path.join(get_package_share_directory('path_planner_server'), 'config', 'planner_server.yaml')
    recovery_yaml = os.path.join(get_package_share_directory('path_planner_server'), 'config', 'recovery.yaml')
    
    return LaunchDescription([     
        Node(
            package='nav2_controller',
            executable='controller_server',
            name='controller_server',
            output='screen',
            parameters=[controller_yaml]),

        Node(
            package='nav2_planner',
            executable='planner_server',
            name='planner_server',
            output='screen',
            parameters=[planner_yaml]),
            
        Node(
            package='nav2_behaviors',
            executable='behavior_server',
            name='recoveries_server',
            parameters=[recovery_yaml],
            output='screen'),

        Node(
            package='nav2_bt_navigator',
            executable='bt_navigator',
            name='bt_navigator',
            output='screen',
            parameters=[bt_navigator_yaml]),

        Node(
            package='nav2_lifecycle_manager',
            executable='lifecycle_manager',
            name='lifecycle_manager_pathplanner',
            output='screen',
            parameters=[{'autostart': True},
                        {'node_names': ['planner_server',
                                        'controller_server',
                                        'recoveries_server',
                                        'bt_navigator']}])
    ])

setup.py:

import os
from glob import glob
from setuptools import setup

package_name = 'project_path_planning'

setup(
    name=package_name,
    version='0.0.0',
    packages=[package_name],
    data_files=[
        ('share/ament_index/resource_index/packages',
            ['resource/' + package_name]),
        ('share/' + package_name, ['package.xml']),
        (os.path.join('share', package_name, 'launch'), glob('launch/*.launch.py')),
        (os.path.join('share', package_name, 'config'), glob('config/*')),
    ],
    install_requires=['setuptools'],
    zip_safe=True,
    maintainer='user',
    maintainer_email='user@todo.todo',
    description='TODO: Package description',
    license='TODO: License declaration',
    tests_require=['pytest'],
    entry_points={
        'console_scripts': [
        ],
    },
)

girishkumar.kannan · March 22, 2024, 11:29am

Hi @ghassan11 ,

Like I said earlier, the problem is in your launch file, in the following lines:

ghassan11:

    controller_yaml = os.path.join(get_package_share_directory('path_planner_server'), 'config', 'controller.yaml')
    bt_navigator_yaml = os.path.join(get_package_share_directory('path_planner_server'), 'config', 'bt_navigator.yaml')
    planner_yaml = os.path.join(get_package_share_directory('path_planner_server'), 'config', 'planner_server.yaml')
    recovery_yaml = os.path.join(get_package_share_directory('path_planner_server'), 'config', 'recovery.yaml')

I think you should change the path_planner_server to project_path_planner. I am assuming you just copy-pasted the config files. I hope you have not copy-pasted all the course packages into your rosject.

Regards,
Girish

ghassan11 · March 22, 2024, 11:31am

yeees reall i did not noticed i should focus more sorry brother thank u for ur help

ghassan11 · March 22, 2024, 11:31am

Thank u Mr @girishkumar.kannan

ghassan11 · March 22, 2024, 11:33am

No don’t worry i did not copied all the files because if i had copied them i wont be in the last part of the project

system · March 27, 2024, 11:33am

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