Accessing your robot’s sensors

Section

Robot hardware - tutorial

In this tutorial we’ll learn how to access to the different sensors of your robot.

Accessing the cameras

Most of the sensor readings of PAL’s robots can be visualized in rviz. Though you can also use image_view or rqt_gui. Let’s have a look at both procedures.

rviz visualization

In order to start the rviz GUI with a predefined configuration you need the <robot>_bringup package corresponding to your robot. It is available from your PAL developer docker image (see Developing with the SDK Docker image and ROS if you have not yet configured your developer environment).

TIAGoARI

Once in your Docker, execute the following command to install tiago_bringup:

apt install pal-gallium-tiago-bringup

Then start rviz:

export ROS_MASTER_URI=http://tiago-0c:11311
rosrun rviz rviz -d `rospack find tiago_bringup\`/config/tiago.rviz

(do not forget to replace tiago-0c with your own robot’s ID!)

The image below shows how the robot’s RGB-D cameras.

image_view visualization

Run image_view tool to visualize the desired camera as follows:

export ROS_MASTER_URI=http://<robot>-0c:11311
rosrun image_view image_view image:=/torso_back_camera/fisheye2/image_raw _image_transport:=compressed

Note

Adapt the topic to your robot. Running rostopic list | grep camera is a quick way of getting the list of available camera topics.

When visualizing images from an external computer through WiFi, it is recommended to use the compressed topic to reduce bandwidth and latency.

rqt_gui visualisation

You can also use rqt_gui, a tool that allows incorporate multiple plugins and thus, have a better understanding of the system. One such example is rqt_human_radar (see ros4hri_tools), a plugin for rqt_gui, where additional visualization tools for ROS4HRI can be combined.

To use rqt_gui, follow the next steps:

1. Run rqt_gui:

   export ROS_MASTER_URI=http://<robot>-0c:11311
   rosrun rqt_gui rqt_gui
   

2. In the top menu, select: Plugins ‣ Visualization ‣ Image View

3. Select the topic of the camera you want to visualize. In the image below we are visualizing the /torso_back_camera/fisheye1/image_raw/*.

Accessing the microphones

Please refer to Microphone array and audio recording to learn how to access the audio data.