Using rviz and rqt

The [rviz] tool(http://wiki.ros.org/rviz) allows real-time visualization of all components of the robotic system —the system of coordinates, moving parts, sensors, camera images — on the 3D stage.

rqt is a set of GUI for analyzing and controlling ROS systems. For example, rqt_image_view allows viewing topics with images, rqt_multiplot allows plot charts by the values in topics, etc.

To use rviz and rqt, a PC running Ubuntu Linux (or a virtual machine such as [Parallels Desktop Lite] (https://itunes.apple.com/ru/app/parallels-desktop-lite/id1085114709?mt=12) or [VirtualBox] (https://www.virtualbox.org)) is required.

Install package ros-melodic-desktop-full or ros-melodic-desktop using the installation documentation.

Start rviz

To start еру visualization of the state of Clover in real time, connect to it via Wi-Fi (CLEVER-xxx) and run rviz, specifying an appropriate ROS_MASTER_URI:

ROS_MASTER_URI=http://192.168.11.1:11311 rviz

If connection is not established, make sure the .bashrc of Clover contains line:

export ROS_HOSTNAME=`hostname`.local

Using rviz

Visualization of the copter position

It is recommended to set the map frame as a reference frame. To visualize the copter, add visualization markers from topic /vehicle_markers. To visualize the camera of the copter, add visualization markers from topic /main_camera/camera_markers.

The result of copter and camera visualization is shown below:

Visualization of the environment

You can view a picture with augmented reality from the topic of the main camera /main_camera/image_raw.

Axis or Grid configured to frame aruco_map will visualize the location on the map of ArUco marks.

jsk_rviz_plugins

It is also recommended to install additional useful plugins for rviz jsk_rviz_plugins. This kit allows visualizing topics like TwistStamped (velocity) CameraInfo, PolygonArray, and many more. To install, use command:

sudo apt-get install ros-melodic-jsk-visualization

Starting the rqt toolkit

To start rqt for monitoring Clover status, use command:

ROS_MASTER_URI=http://192.168.11.1:11311 rqt

An example of starting a specific plugin (rqt_image_view):

ROS_MASTER_URI=http://192.168.11.1:11311 rqt_image_view

Brief description of useful rqt plugins:

• rqt_image_view – viewing images from topics like sensor_msgs/Image;
• rqt_multiplot – Building charts from the data from of arbitrary topics (installation: sudo apt-get install ros-melodic-rqt-multiplot);
• Bag – working with Bag-files.