Controlling the real robot

You can control Robotont using either your keyboard, a gamepad or a web-based interface. This section explains how to send movement commands to the robot and interact using both methods.

_images/coord.png

  • The robot driver subscribes to a specific type of messages called velocity commands. The standard name for this topic is /cmd_vel.

  • The message is of type geometry_msgs/Twist — see its structure on the ROS 2 geometry_msgs/Twist documentation.

  • To set and control the robot speed, the velocity commands need to be published continuously.

Controlling the robot using teleop twist keyboard

Setup

Hint

Before installing any packages from apt, make sure existing packages are up-to-date:

sudo apt update && sudo apt upgrade -y

Hint

ROS packages installed from apt are only available in terminals where the ROS environment has been sourced. To use these packages, you must first source the general ROS 2 environment:

source /opt/ros/jazzy/setup.bash

  1. Install teleop twist keyboard from apt:

    sudo apt install ros-jazzy-teleop-twist-keyboard

  2. (Optional) Connect the robot and PC with the same subnet (see Distributed ROS 2).

Controlling the robot

  1. In Terminal (on the robot’s on-board computer or another PC, if distributed ROS is set up):

    ros2 run teleop_twist_keyboard teleop_twist_keyboard

  2. Use the following keys to move the robot:

    _images/teleop_twist_terminal.png

    Warning

    From this point beyond, you are able to drive the robot with a keyboard. Should you lose control over the robot, do one of the following:

    • Press “k” to stop the robot

    • Press the emergency stop button on the robot

    Hint

    Note that teleop only receives keypresses when the terminal window is active (in focus).

    Tip

    Use CTRL + C to stop the node.

Controlling the robot using a gamepad

Setup

Connecting a controller

Hint

Before installing any packages from apt, make sure existing packages are up-to-date:

sudo apt update && sudo apt upgrade -y

  1. Install bluetooth, bluez and bluez-tools from apt

    sudo apt install bluetooth bluez bluez-tools

  2. Put your controller into pairing mode

    Note

    demo_teleop package includes the configuration file for DualSense® controller.

    To put the DualSense controller into pairing mode:

    • Hold the PS button and the Create button down for a few seconds

    • The light bar will start rapidly flashing blue, which indicates, that the controller is in pairing mode

  3. In Terminal, start the Bluetooth CLI tool:

    bluetoothctl

  4. Turn on the Bluetooth agent and scanning:

    power on
agent on
scan on

  5. Wait for your controller to appear

    Note

    It should look something like: Device XX:XX:XX:XX:XX:XX Wireless Controller

  6. Pair and connect the controller:

    Replace XX:XX:XX:XX:XX:XX with your controller’s MAC address:

    pair XX:XX:XX:XX:XX:XX
connect XX:XX:XX:XX:XX:XX
trust XX:XX:XX:XX:XX:XX

  7. Stop scanning and exit the tool:

    scan off
exit

Dependencies

Hint

ROS packages installed from apt are only available in terminals where the ROS environment has been sourced. To use these packages, you must first source the general ROS 2 environment:

source /opt/ros/jazzy/setup.bash

  1. Install joy from apt:

    sudo apt install ros-jazzy-joy

  2. Navigate to your colcon workspace:

    cd ~/<your_colcon_workspace>/src

  3. Clone the demo_teleop package:

    git clone https://github.com/robotont-demos/demo_teleop.git

  4. Build the package:

    colcon build --packages-select demo_teleop

  5. (Optional) Connect the robot and PC with the same subnet (see Distributed ROS 2).

Controlling the robot

  1. In Terminal (on the robot’s on-board computer or another PC, if distributed ROS is set up):

    ros2 launch demo_teleop teleop_joy.launch.py

  2. The robot can be controlled using the joysticks:

    _images/dualsense_conf.png

Warning

From this point beyond, you are able to drive the robot with a controller. Should you lose control over the robot, do one of the following:

  • Use CTRL + C to stop the node.

  • Press the emergency stop button on the robot

Controlling the robot using a web interface

Important

Make sure that the user’s device and the robot are connected to the same subnet and are visible to one another (see Verifying Communication).

  1. Open the following URL in your web browser (replace <ip-of-the-robot> with the actual IP address of your robot):

    http://<ip-of-the-robot>:3000/

    You should see the following page:

    _images/webapp_ok_step.png

  2. Click OK to close the connection status dialog

  3. You can now control the robot using the on-screen joystick and view both the camera feed and depth cloud in your browser.

    _images/webapp3.png