part6_ros2_nav2.md

Learning Source:
https://youtu.be/idQb2pB-h2Q

sudo apt update

sudo apt install ros-humble-navigation2 ros-humble-nav2-bringup ros-humble-turtlebot3*

gedit ~/.bashrc

Add

export TURTLEBOT3_MODEL=waffle

before the line source /opt/ros/humble/setup.bash

To see

printenv | grep TURTLE

Test gazebo

gazebo

ros2 launch turtlebot3_gazebo turtlebot3_world.launch.py

To see in rviz

ros2 launch turtlebot3_cartographer cartographer.launch.py use_sim_time:=True

To drive the robot start a keyboard

ros2 run turtlebot3_teleop teleop_keyboard

To save the map

ros2 run nav2_map_server map_saver_cli -f maps/my_map

To start a new world that is different from previous

ros2 launch turtlebot3_gazebo turtlebot3_house.launch.py

Install Cyclone DDS

sudo apt install ros-humble-rmw-cyclonedds-cpp

add to bashrc

gedit ~/.bashrc

add the below line just before "source /opt/ros/humble/setup.bash"

export RMW_IMPLEMENTATION=rmw_cyclonedds_cpp

So the bottom part of our bashrc file now looks like

export TURTLEBOT3_MODEL=waffle
export RMW_IMPLEMENTATION=rmw_cyclonedds_cpp
source /opt/ros/humble/setup.bash
source /usr/share/colcon_argcomplete/hook/colcon-argcomplete.bash
source ~/ros2_ws/install/setup.bash

Now we will edit some parameters,

cd /opt/ros/humble/share/turtlebot3_navigation2/param
sudo gedit waffle.yaml

Now change robot_model_type: "differential" to

robot_model_type: "nav2_amcl::DifferentialMotionModel"

Starting navigation

ros2 launch turtlebot3_navigation2 navigation2.launch.py use_sim_time:=True map:=maps/my_map.yaml

Global Planner, Local Planner, Costmaps

will be added

Recovery Behavior

will be added

TF

To see TF topic

ros2 topic list

ros2 topic echo /tf

to export TF tree as pdf(it will listen to tf topics for 5 second and then it will export as pdf)

ros2 run tf2_tools view_frames 

Building World in Gazebo, Make Turtlebot Navigate in World

We will start navigating Turtlebot in our own world. After making a world in gazebo we will clone turtlebot repository in our machine and we will include our world in this repository

Step 1: Make a workspace name turtlebot3_ws

mkdir turtlebot3_ws

cd turtlebot3_ws
mkdir src
cd src

Step 2: clone the repository

git clone https://github.com/ROBOTIS-GIT/turtlebot3_simulations.git .

. means clone here without making any directory. Now switch to humble-devel branch(according to your ros version)

git checkout humble-devel

Step 3: Build the repository using colcon and source to the bashrc

colcon build

source this workspace to bashrc

gedit ~/.bashrc 

and add

source ~/turtlebot3_ws/install/setup.bash

this line at the end of the file.

Step 4: Add our world to our cloned repository and edit the launch file to drive the turtblebot to our own world.

Cut and paste our newely created "my_world.world" file to cd ~/turtlebot3_ws/src/turtlebot3_gazebo/worlds

Step 5: Edit the launch file with our world

go to

cd ~/turtlebot3_ws/src/turtlebot3_gazebo/worlds

cp turtlebot3_house.launch.py turtlebot3_my_world.launch.py

Now open turtlebot3_my_world.launch.py and fine the below line and replace with our own world file

  world = os.path.join(
        get_package_share_directory('turtlebot3_gazebo'),
        'worlds',
        'my_world.world'
    )

Step 6: Build the workspace

cd ~/turtlebot3_ws/

colcon build

Open a new terminal or

source install/setup.bash

Step 7:

ros2 launch turtlebot3_gazebo turtlebot3_my_world.launch.py

if gazebo hangs or crashes edit the pose(x_pose and y_pose) position of the launch file from which position robot should launch.(Edit "turtlebot3_my_world.launch.py" file)

 x_pose = LaunchConfiguration('x_pose', default='-0.0')
 y_pose = LaunchConfiguration('y_pose', default='-0.0')

Step 8: Drive the robot manually in this world

ros2 run turtlebot3_teleop teleop_keyboard

Step 9: Navigate and Create Map.

Drive the turtlebot and save the map like the previous one.

Step 10: Clean the Map using Gimp or any photo editor

Open the map using Gimp photo editor. Make the black line where necessary and also clear the unclear spaces.

Step 11: Run turtlebot3 in the world, create map, navigate

ros2 launch turtlebot3_gazebo turtlebot3_my_world.launch.py

To see in rviz

ros2 launch turtlebot3_cartographer cartographer.launch.py use_sim_time:=True

To drive the robot start a keyboard

ros2 run turtlebot3_teleop teleop_keyboard

To save the map

ros2 run nav2_map_server map_saver_cli -f maps/my_map_singlehouse

To navigate

ros2 launch turtlebot3_navigation2 navigation2.launch.py use_sim_time:=True map:=maps/my_map_singlehouse.yaml