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## title = Mapping and Navigation with Turtlebot
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## description = This tutorial shows how to use RTAB-Map with Turtlebot for mapping and navigation.
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<<TableOfContents(3)>>

== Introduction ==
(Originally from [[http://official-rtab-map-forum.67519.x6.nabble.com/Demo-RTAB-Map-on-Turtlebot-td439.html|this post from RTAB-Map's forum]])

This page will show how to use rtabmap with navigation stack on a Turtlebot3. 

{{attachment:overview_tf_rtabmap.png|Overview|width="700"}}

Requirements:
{{{
# Noetic:
sudo apt install ros-noetic-rtabmap-demos ros-noetic-turtlebot3-simulations ros-noetic-turtlebot3-navigation ros-noetic-dwa-local-planner 
}}}

{{attachment:turtlebot_mapping.png|Turtlebot mapping with rtabmap}}

Usage:
{{{
export TURTLEBOT3_MODEL=waffle
roslaunch turtlebot3_gazebo turtlebot3_world.launch

export TURTLEBOT3_MODEL=waffle
roslaunch rtabmap_demos demo_turtlebot3_navigation.launch
}}}

== Autonomous Navigation ==
When a map is created (in mapping mode or localization mode), you can then follow the same steps from 2.3.2 of the [[http://wiki.ros.org/turtlebot_navigation/Tutorials/Autonomously%20navigate%20in%20a%20known%20map#Teleoperation|Autonomous Navigation of a Known Map with TurtleBot]] tutorial to navigate in the map.

Normally, you only have to "drop" a navigation goal on the map with RVIZ to see the robot moving autonomously to it. Click on "2D Nav Goal" button in RVIZ to set a goal. You should see a planned path (red line) like this to the goal set (green arrow): 

{{attachment:turtlebot_navigation.png|Turtlebot navigation with rtabmap}}

The commands sent by [[move_base]]: 
{{{
$ rostopic echo /mobile_base/commands/velocity
}}}

== Localization mode ==
After a mapping session as above, a database is saved here `~/.ros/rtabmap.db`. Now restart the `demo_turtlebot3_navigation.launch` with argument `localization:=true`:
{{{
 $ roslaunch rtabmap_demos demo_turtlebot3_navigation.launch localization:=true
}}}
Move the robot around until it can relocalize in the previous map, then the 2D map would re-appear again when a loop closure is found. 





== Issues ==

 * On autonomous navigation, if teleop node is also sending commands on the same topic as `move_base` at the same time, the robot may not move.

 * If there are many TF warnings, you can try to increase `robot_state_publisher`'s publishing frequency in `turtlebot_bringup/launch/includes/robot.launch.xml` from 5 to 10 Hz. You can also increase `wait_for_transform argument` of [[https://github.com/introlab/rtabmap_ros/blob/master/rtabmap_demos/launch/demo_turtlebot_mapping.launch|demo_turtlebot_mapping.launch]] to `0.2`.

 * If sometimes the robot is planning a straight path through an obstacle, it may be related to this [[https://github.com/ros-planning/navigation/issues/320|issue]]. This can be fixed by using `rtabmap_costmap_plugins::StaticLayer` instead of `costmap_2d::StaticLayer` [[https://github.com/turtlebot/turtlebot_apps/blob/indigo/turtlebot_navigation/param/global_costmap_params.yaml#L9|here]].