🧪 MICKY Simulation

This section guides you through running the MICKY simulation environment using Gazebo and ROS 2.

Step 1 — Launch Gazebo

  1. Opens Gazebo Harmonic with the turtlebot3_world world and spawns the Micky robot.

ros2 launch micky_simulation gazebo.launch.py

Wait until Gazebo GUI is fully open and the robot model is visible in the scene.

Step 2 — Launch SLAM

  1. In a new terminal, start the SLAM node and RViz:

ros2 launch micky_slam sim_slam.launch.py

RViz will open with the /map topic displayed. The map starts empty and is built as the robot moves.

Step 3 — Drive the Robot (Teleop)

  1. In a third terminal, start the keyboard teleop:

ros2 run teleop_twist_keyboard teleop_twist_keyboard

Key

Action

i / ,

Forward / backward

j / l

Strafe left / right

u / o

Rotate left / right

space

Stop

w / x

Increase / decrease linear speed

Drive the robot around the entire environment. The map in RViz fills in as new areas are scanned. For best results, make at least one full loop so slam_toolbox can close the loop.

  1. The robot can be vizualized and controled with teleop, like the image below:

Step 4 — Save the Map

Once the environment is fully mapped, run in any terminal:

ros2 run nav2_map_server map_saver_cli -f ~/micky_map

This generates two files:

  • ~/your_map.pgm — the occupancy grid image

  • ~/your_map.yaml — metadata (resolution, origin, thresholds)

Common Troubleshooting

Gazebo does not open / freezes on startup

pkill -f gz_sim && pkill -f gzserver
unset IGN_PARTITION GZ_PARTITION

Then re-run Step 1.

Map stays empty in RViz

  1. Check that the LiDAR is publishing:

    ros2 topic echo /laser_scan_front
# Expected: ~10 Hz

  2. Move the robot — slam_toolbox only registers a new scan after the robot travels at least 0.5 m.

Robot does not move

# Test the command manually
ros2 topic pub /cmd_vel geometry_msgs/msg/Twist \
  "{linear: {x: 0.2, y: 0.0, z: 0.0}, angular: {z: 0.0}}" --once

If the robot moves in Gazebo but not from teleop, make sure the teleop terminal has focus (keyboard input is captured there).