How to teleoperate your robot#

🏁 Goal of this tutorial

By the end of this tutorial, you will know how to teleoperate your robot (or its simulation) using different methods, such as a joystick, the keyboard, or ROS’s RViz.

Pre-requisites#

You should be able to remotely connect to your robot Set up ROS 2 communication with the robot.

You should be familiar with ROS’s RViz

Teleoperate the robot using the Keyboard#

Key-based teleoperation can be performed using the key_teleop node. This allows the user to control the robot’s movement through keyboard inputs, offering an intuitive way to drive the robot without requiring a physical joystick, making it ideal for quick testing or remote operation in various environments. his teleoperation method can be used both in simulation and on the real robot. To start the key_teleop node, first install it using the command:

sudo apt-get install ros-$ROS_DISTRO-key-teleop

Then you can run the key_teleop node using the following command:

ros2 run key_teleop key_teleop

Then use the following keys to control the robot:

Instruction	Keyboard keys
Move Forward	`↑`
Move Backward	`↓`
Rotate Left	`←`
Rotate Right	`→`

Note

The key_teleop node is included in the teleop_tools This teleop method does not support holonomic movement, meaning it only allows for non-holonomic control (forward, backward, and rotational movement).

Teleoperate the robot using the Joystick#

Joystick-based teleoperation is performed using the joy_teleop node, it publishes velocity commands to the /joy_vel topic; this allows the user to control the robot’s movement through a physical gamepad, offering an intuitive way to drive the robot with real-time feedback. It is ideal for precise control in dynamic environments and provides a reliable interface for remote operation. This teleoperation method can be used in the real robot. The joy_teleop node is automatically started at the startup of the robot.

To confirm that this node is running and that you can teleoperate the robot using the joystick, you can use the following command:

pal module info joystick

Which should return:

Status: RUNNING

Then, to control the robot, use the following joystick buttons:

Attention

Before moving the robot, press START in order to give command priority to the gamepad.

Attention

To use the robot in autonomous navigation mode you need to disable the gamepad, if the priority has been taken previously by the gamepad. To do so, press START on the gamepad.

(coloured commands indicate that you have to press 2 keys at a time in order to perform the action.)

Instruction	Gamepad keys
Enable Gamepad	`START`
Move	`RB` + Left Joystick
Rotate	`RB` + Right Joystick
Increase Linear Velocity	`BACK+Y`
Decrease Linear Velocity	`BACK+A`
Increase Angular Velocity	`BACK+X`
Decrease Angular Velocity	`BACK+B`
Reset settings	Press Right Joystick or Left Joystick

Moreover is possible to enable and disable Gamepad using the following ROS 2 action:

ros2 action send_goal /joy_teleop_priority_action twist_mux_msgs/action/JoyPriority {}

Note

This action is equivalent to pressing the START button on the gamepad.

Teleoperate the robot using RViz#

Note

The virtual joystick is available only with advanced_navigation package.

In addition to the physical joystick, a virtual joystick can be used to teleoperate the robot. The virtual joystick is part of PAL Navigation 2 rviz plugins, you can load it by clicking on Add New Panel on the Panels tab in RViz2 and selecting the PAL Navigation 2 plugins.

It virtualizes the joystick pads and allows the user to control the robot’s movement with the mouse. This teleoperation method can be used both in simulation and on the real robot.

It supports both holonomic and non-holonomic control, the user can switch to Omnidirectional Mode using a dedicated toggle switch.

../_images/virtual_joystick_teleop_omni.svg

To start using the Virtual Joystick to send velocity commands to the robot, first use the Enable Switch to enable the publisher, then use the joystick pads to control the robot’s movement.

Attention

While the Virtual Joystick is enabled, it takes priority over the Autonomous Navigation system. To allow the robot to navigate autonomously, make sure to Disable the Virtual Joystick by using the appropriate switch.

Next steps#

To learn more about teleoperation you can refer to the chapter 🎮 Teleop.