Student Rosbridge API

A small Python API for students who use an ML model or robotics modelling toolbox to control a ROS robot through rosbridge. It exposes only the main operations a student control loop needs:

• sign in to borrow the robot and another sign-in for the battery
• log into turtlebot-MMR wifi, pwd: Turtlebot
• ping 192.168.1.2XX where XX is the TurtleBot ID
• query the latest compressed camera image as a BGR NumPy array;
• query the latest laser scan as angle and range NumPy arrays;
• publish linear and angular velocity to /cmd_vel;
• stop and disconnect safely.

Robot requirements

The robot must:

1. run a rosbridge WebSocket server reachable by the student's computer;
2. accept geometry_msgs/msg/Twist messages on /cmd_vel;
3. publish sensor_msgs/msg/CompressedImage messages on /camera/image_raw/compressed;
4. publish sensor_msgs/msg/LaserScan messages on /scan.

Topic names can be changed when constructing RosbridgeRobot.

Install locally for testing

From this directory:

python -m pip install .

Include the keyboard teleoperation dependency with:

python -m pip install ".[teleop]"

For active development, use an editable installation:

python -m pip install -e ".[teleop,dev]"

ML/control-loop example

from rosbridge_api import RosbridgeRobot

with RosbridgeRobot("192.168.1.213") as robot:
    while True:
        image = robot.query_image(timeout=2.0, wait_for_new=True)
        if image is None:
            continue

        linear_velocity, angular_velocity = controller(image)
        robot.send_command(linear_velocity, angular_velocity)

query_image() returns a copy, so student code may safely annotate or resize it. Its colour order is BGR, as expected by OpenCV.

Included examples

The runnable examples are kept separately from the library in examples/. After installing the package, run them from the project directory:

python examples/camera.py 192.168.1.213
python examples/laser_scan.py 192.168.1.213
python examples/teleop.py 192.168.1.213

The camera and laser-scan visualisers exit with Q or Escape. The teleop controls are W/S for forward/backward, A/D for turning, Space for an immediate stop, and Escape to exit.

Test and build

python -m unittest discover -s tests -v
python -m build
python -m twine check --strict dist/*

The tests mock rosbridge and do not require a physical robot.

Before publishing, choose the final project name, add author/project metadata, choose a licence, and verify installation from the generated wheel in a clean virtual environment.