ros2_dcs_turtlesim

This project is a ROS2 Package wrapper for the TurtleSim demo with DroidControlShip (DCS) and RadonUlzer (RU) robots under Webots.

These robot projects are build using PlatformIO. The ros2_dcs_turtlesim package creates a ROS2 cmake wrapper around them and adds a launch configuration for the turtle demo.

Workspace Setup

Checkout ros2_dcs_turtlesim into your ROS2 workspace

Go into the src folder of your ros2 workspace and checkout this repository there:

    cd ros2_webots_ws/src
    git clone https://github.com/nhjschulz/ros2_dcs_turtlesim

Checkout the dependend PlatformIO projects

Checkout the following PlatformIO projects to a fitting location. This should not be inside your ROS workspace, as these are not ROS2 packages:

• RadonUlzer: https://github.com/BlueAndi/RadonUlzer

• DroidControlShip: https://github.com/BlueAndi/DroidControlShip (Branch feature/ROS2)

    git clone https://github.com/BlueAndi/RadonUlzer
    git clone https://github.com/BlueAndi/DroidControlShip
    cd DroidControlShip
    git checkout feature/ROS2
  

• Link the micro-ROS library to the lib folder of DCS

    cd DroidControlShip/lib
    ln -s ~/microros_ws/firmware/build libmicroros
  

Add the following environment variables which tell ros2_dcs_turtlesim where the PlatformIO based projects are:

    export DCS_HOME=<checkout location of DroidControlShip>
    export RU_HOME=<checkout location of RadonUlzer>

Building

Go into your ROS2 workspace and use the normal ROS2 commands for building

    colcon build
    source install/local_setup.bash

The first build must be the complete workspace. Later it is possible to build only this package (and in verbose mode) use:

    colcon build --event-handlers console_direct+ --cmake-args -DCMAKE_VERBOSE_MAKEFILE=ON  --packages-select ros2_dcs_turtlesim
    source install/local_setup.bash

Note

If you get error fatal error: rcl/rcl.h: No such file or directory, you forgot to link the micro-ROS library into the DCS workspace.

Launching

The ros2_dcs_turtlesim includes a launch configuration. Run it using

    ros2 launch ros2_dcs_turtlesim dcs_launch.py [args]

Note

The argument launch_xrce:=true is required unless the xrce agent is already running as a demon or in another terminal.

Supported launcher arguments:

Argument	Default	Description
world	world:=worlds/minimal/DcsMinimal.wbt	Launch Webots with given world file.
launch_webots	launch_webots:=true	Enable/Disable launch of Webots.
launch_ru	launch_ru:=true	Enable/Disable launch of RadonUlzer controller.
launch_dcs	launch_dcs:=true	Enable/Disable launch of DroidControlShip controller.
launch_xrce	launch_xrce:=false	Enable/disable launch of the XRCE agent process.
xrce_agent	xrce_agent:='/usr/local/bin/MicroXRCEAgent tcp4 -p 1883'	Define command line for XRCE agent.
log_redirect	log_redirect:=false	Enable/Disable output redirection of Webots controllers to Webots console.

Controlling the Robot

The robot listens to Twist messages similar to the ROS2 TurtleSim demo. The turtle_teleop_key tool can be used to control it using the keyboard. Use the following command from a second terminal window for controlling the robot:

    ros2 run turtlesim turtle_teleop_key --ros-args --remap turtle1/cmd_vel:=/cmd_vel