• Students are expected to work in teams by two (exceptions allowed after consultation with the teacher).
• Each group is expected to work with a real robot.
• Majority of the work is planned as an individual work of the group (you can work anytime the room is available).
• Students are expected to ask - ask early, ask often.
• Teachers will be personally available during the regularly scheduled hours, otherwise over the e-mail (but don't expect answers in order of minutes)
• Charge the robot every time you stop working with it.
• Keep your source code on a version-control system (e.g. git). This way, you can remove commented-out parts of your source code that you'd like to keep “just in case”, the version control system will keep a trace of it.

• slides

• Each team is asked to implement selected algorithms presented on lectures:
  • Multi-robot motion coordination
    • slides
    • Presentation of WHCA*
    • D. Silver, Cooperative Pathfinding (alternatively this other version of the article)
    • Skeleton
  • Particle filter for global localization
    • Slides
    • Video with motion model demonstration
    • Dataset and map
    • More challenging datasets with dynamic obstacles or odometry perturbances
    • Skeleton for the motion model and the entire particle filter
  • Implementation on real robots

The tasks will be assessed at the end of the semester but can be assessed sooner if the team wishes so.

To get the seminar credit, student must:

• Participate and actively work at all seminars (up to 2 absences without excuse will be tolerated),
• Create working algorithms solving *all* the tasks,
• Present a well-written and documented source code,
• Understand the presented solution and source code (each team member).

• Log into a PC with the disk-less operating system, either physically on one of the lab's PC or remotely with

ssh {username}@turtle.felk.cvut.cz. On these systems, your personal NFS folder will be mounted as $HOME. Before you can log remotely, you need to set a password through this page.

• singularity shell /opt/singularity/robolab/noetic.
• In the singularity shell that opens, create a directory that will be your ROS workspace and go to it (e.g. mkdir $HOME/mkr_ws && cd $HOME/mkr_ws), then export ROS_WORKSPACE="$(pwd)" && mkdir src && source /opt/ros/mkr/setup.bash && catkin init && catkin build.
• cd "$ROS_WORKSPACE/src" && git clone https://gitlab.ciirc.cvut.cz/imr/mkr/ros_skeletons.git && catkin build

To use the turtlebots:

• Switch on the base and the onboard PC.
• Connect your PC to the wifi e210bot.
• Connect to the robot with ssh {usermap_username}@192.168.210.{20+turtlebot_number}.
• export ROS_IP=$(echo -n $(hostname))
• singularity shell /opt/singularity/robolab/noetic.
• tmux.
• In the each new tmux window source $ROS_WORKSPACE/devel/setup.bash.
• In the first tmux window roscore. roslaunch itself would run roscore if no ROS master is detected but this master will be killed when the roslaunch command finishes (usually with Ctrl+C) and nodes such as rqt or rviz would have to be closed as well. It is then better to run roscore separately.
• In the second tmux window export HOSTNAME && roslaunch robolab_bringup turtlebot2.launch camera:=false.
• See multi_robot_planner/launch/two_turtlebots_in_flatland.launch for an example of launch file for the multi_robot_planner/planner node. You can then send goal from RViz (rosrun rviz rviz -d "$(rospack find simulator_e130)/rviz/two_turtlebots_in_flatland.rviz") by clicking on “2D Nav Goal” then clicking in the map as many times as the robot count within 30 seconds.

The simulator used is Flatland. The graphical interface to Flatland is RViz.

• singularity shell /opt/singularity/robolab/noetic then source $ROS_WORKSPACE/devel/setup.bash.
• roslaunch simulator_e130 two_turtlebots_in_flatland.launch. For the multi-robot planning task, you can also launch roslaunch multi_robot_planner two_turtlebots_in_flatland.launch, which also launches the planning node (multi_robot_planner) and the nodes that execute the trajectories (/turtle0/coordinator and /turtle1/coordinator).
• You can then send goal from RViz by clicking on “2D Nav Goal” then clicking in the map as many times as the robot count within 30 seconds.

- ssh {usermap_username}@turtle.felk.cvut.cz. On this system, your personal NFS folder will be mounted as $HOME. Before you can log remotely, you need to set a password through this page. - alternatively, you can remotely start one of the lab's computer and log to it.

1. Start the computer with ssh student@turtle.felk.cvut.cz (ask for password if you forgot it) and follow the instructions
2. ssh {usermap_username}@turtle.felk.cvut.cz
3. ssh {usermap_username}@desktop01 if you started desktop01.
4. Please then turn off the computer with the shell command poweroff when you are done.

You can also load a remote desktop to use graphical applications. Only physical computers can be used for this. More information on this page:

- ssh student@turtle.felk.cvut.cz and follow the instructions. - tmux if you want to be able to open further text shells - remote-desktop start xpra, note the actual used display (e.g. ':1') - On your PC, start Xpra. Choose the method SSH→SSH (not available on Xpra version 2), username: usermap's username, proxy: turtle.felk.cvut.cz, hostname: desktop-01 or the one where you called remote-desktop.

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