RQT Setup in ROS2 Humble

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If you’re developing with ROS 2 and want an easy way to visualize topics, monitor nodes, or interact with parameters, look no further than RQT.

In this guide, we’ll walk through:

  • Installing RQT in ROS 2 Humble

  • Running a basic Turtlesim demo

  • Using RQT plugins like rqt_graph, rqt_plot, and rqt_console

Let’s get started.

Prerequisites

Before we dive in, make sure:

  • You’re using Ubuntu 22.04

  • You’ve installed ROS 2 Humble

  • Your environment is sourced properly:

        source /opt/ros/humble/setup.bash

1. Introduction

RQT is a GUI framework for ROS (Robot Operating System) that allows users to create and manage plugins for visualization, debugging, and system introspection. In ROS 2, RQT has been adapted to work with the new middleware and tools.

2. Installing RQT in ROS 2

RQT is included in the default ROS 2 installation but can be installed separately if needed.

2.1 Install RQT Core Packages

Run the following command:



sudo apt install ros-humble-rqt*

Alternatively, install only essential RQT packages:

sudo apt install ros-humble-rqt-gui ros-humble-rqt-common-plugins

2.2 Verify Installation

Check if RQT is installed correctly:

ros2 pkg xml rqt_gui | grep version

(Should display the installed version.)

3. Launch the Turtlesim Node

Let’s start a minimal ROS 2 system using Turtlesim.In one terminal start the turtle_node

ros2 run turtlesim turtlesim_node

  • In another terminal, start the teleop node

ros2 run turtlesim turtle_teleop_key






  • Use arrow keys to move the turtle around

4. Launch RQT

Now let’s visualize what’s going on behind the scenes.


rqt

This opens the RQT GUI.


5. View the Node Graph

Go to Plugins>Introspection>Node Graph



Here you can see how nodes like turtlesim and teleop_turtle are communicating.
This helps you understand the data flow in your ROS graph.

Oval represents a node

Rectangles with arrows pointing towards them are topics.

Subscribers turn Green when you hover over a topic or node. The node or topic being hovered over turns red

Publishers turn Blue.


6. Loading RQT Plugins

RQT provides various plugins for debugging and visualization:


  • Topic Monitor (rqt_topic)

  • Node Graph (rqt_graph)

  • Service Caller (rqt_service_caller)

  • Bag Tools (rqt_bag)

  • Console (rqt_console)

  • Plot (rqt_plot)

  • Image View (rqt_image_view)

To load a plugin:

  1. Open RQT (rqt).

  2. Go to Plugins > Select desired plugin.

Common RQT Plugins in ROS 2

    1. Topic Monitor (rqt_topic)

  • Monitors active topics and message rates.

  • Launch via:

    ros2 run rqt_topic rqt_topic

Or go to Plugins>Topics>Topic Monitor


    2.  Node Graph (rqt_graph)

  • Visualizes ROS 2 node communication.

  • Launch via:

    ros2 run rqt_graph rqt_graph

Or go to Plugins>Introspection>Node Graph

    3. Service Caller (rqt_service_caller)

  • Allows calling ROS 2 services interactively.

  • Launch via:

    ros2 run rqt_service_caller rqt_service_caller

Or go to Plugins>Services>Service Caller

    4. Plot (`rqt_plot)

  • Plots numerical topic data in real-time.

  • Launch via:

    ros2 run rqt_plot rqt_plot

Or go to Plugins>Visualization>Plot

    5. Image View (rqt_image_view)

  • Displays image topics (from sensor_msgs/Image).

  • Launch via:

    ros2 run rqt_image_view rqt_image_view

Or go to Plugins>Visualization>Image View

7. Troubleshooting

  • RQT not opening?

    Ensure ROS 2 is sourced (source /opt/ros/<distro>/setup.bash).
    Reinstall

  • Plugins missing?

    sudo apt install ros-humble-rqt-common-plugins

  • Python errors when launching RQT?
    Make sure all Python dependencies are installed using rosdep:

            sudo rosdep init        rosdep update





Navigate to your workspace and run:

           rosdep install -y --from-paths src --ignore-src

This resolves missing system dependencies required by your ROS 2 packages, including RQT plugins.

  • Empty Node Graph?
    • Ensure the nodes are running and your ROS environment is sourced in the same shell.

Conclusion

RQT offers powerful GUI tools that simplify your ROS 2 development experience. Whether you're debugging, visualizing, or tuning—RQT should be part of your workflow.

Next time your robot misbehaves, don’t panic—just open RQT.

Happy coding!

References


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