This documentation is meant to help an end user to bring a Clearpath Jackal to the point of being able to perform autonomous reconnaissance missions.
The user will be able to perform keyboard or game controller teleoperation for missions, or for troubleshooting. The user will also be able to use image_view
or rviz to visualize LiDAR and depth camera images. [MORE?]
The capabilities discussed below can be examined as modules associated with the Jackal platform, or individual sensors, or as more complex behaviors integrating
one or more sensors with the mobile platform. The modules can be seen as building blocks and or troubleshooting tools for developing the bigger behaviors.
If approached in a certain order, the capabilities will build on each other. The prerequisites are as follows based on context.
| Context | Jackal | Intel RS D435i | GC Computer | Monitor | Mouse | Keyboard | Joystick |
|---|---|---|---|---|---|---|---|
| Teleoperation | Y | N | O | Y | Y | O | O |
| Intel RS D435i Image Viz | N | Y | Y | N | N | N | N |
| Intel RS D435i Pointcloud Viz | N | Y | Y | O | O | O | N |
| Intel RS D435i PC to LaserScan | N | Y | Y | O | O | O | N |
| Intel RS D435i SLAM | N | Y | Y | O | O | O | N |
| Google Cartographer w/Jackal and Intel RS D435i | Y | Y | Y | O | O | O | O |
Network configuration in this context refers to setting up the hardware, and software settings to enable the Jackal onboard computer, companion computer, and ground station computer to all be on the same network, and communicate smoothly among machines using ROS. The strategy entails configuring the companion computer to be a mobile WiFi hospot to which the onboard and ground control computers will both connect.
- On your companion computer (e.g. NUC, Brix, etc.), open the network manager connection editor:
nm-connection-editor
- Choose the plus sign to add a connections
- Choose Wi-Fi for "Connection Type" and click "Create..."
- On the Wi-Fi tab:
- Set "Connection Name:" to [Companion Name]Hotspot (e.g. NUC40Hotspot]
- Set "Mode:" to Hotspot
- Set "SSID:" to [Companion Name] (e.g. NUC40)
- On the Wi-Fi Security Tab
- Set "Security:" to WPA & WPA2 Personal
- Set the password: nuc40access (or similar based on the name of your companion machine)
- On the General Tab
- Make sure 'Automatically connect ...' is checked
You will want to edit the root .bashrc file on your development/ground control machine, and your companion computer. Do not edit files on the onboard Jackal computer. If you suspect you may need to edit a file on the onboard computer, please consult your instructor or an advisor. And remember, for all examples below, your IP addresses may be different than what is shown.
In a terminal, in the home directory ("~"), use your favorite editor to edit .bashrc:
sudo gedit .bashrc
The minimum to do here is to export the ROS Master and ROS IP values:
ifconfig- Look for the wireless IP address: this will be your ROS_IP
- Open your WiFi Settings and find the network you set up in the "Network Configuration" section. The IP address of this network will be your ROS_MASTER_URI
export ROS_MASTER_URI=http://10.42.0.127:11311export ROS_IP=10.212.199.192
You may also want to create an alias for connecting to the Jackal companion computer if the .bashrc file you are editing is on your dev computer:
alias ssh-jackal-companion='ssh user1@10.212.199.192
Once you are done editing, save your work and exit your text editor. Now it's time to source .bashrc within your work environment:
source .bashrc
NOTE: For development, you may want a secondary bashrc file, e.g. ".dev-bashrc". You will want to modify this in a similar fashion, but with ROS_MASTER_URI being the same as ROS_IP. Which is to say, you are setting your development machine to be ROS Master. This makes it easy to plug a sensor into your development machine and experiment with different packages and nodes without having to worry about your entire robot setup, including power, etc.
There are two main ways to remotely control the Jackal: by joystick (e.g. PS4 remote), and by keyboard. Whichever of these you pursue, until you have confirmed that you have your setup working, you should have the Jackal on blocks so the wheels will not spin on a surface.
For the joystick control, the companion computer and onboard computer have to have the same ROS_MASTER_URI (as explained above), and the Bluetooth on the companion must be turned on. If the PS4 is not paired, turn it on, and hold down the PS and Share buttons (press the Share button slightly ahead of PS) until the front light turns steady blue. You should then be able to hold down the left bumper and use the left joy to control the Jackal.
For keyboard control, you will need to open a terminal on your development/ground control computer and navigate to the source folder within a catkinized workspace.
cd ~/catkin_ws/src
Clone down the generic keyboard teleop package from ros-teleop:
git clone /~https://github.com/ros-teleop/teleop_twist_keyboard
Now you can run the keyboard node:
rosrun teleop_twist_keyboard teleop_twist_keyboard.py
The package displays what happens in response to the relevant keys in the terminal.
For reference of what you'll be interfacing with on the Jackal onboard, see the jackal repository, which has all the base Jackal packages.
To get anything to work with the Intel RealSense D435i camera, you will need librealsense (drivers), and realsense-ros. The realsense-ros package will explain some basic nodes you can run to test out your camera setup. Beyond that, it is fairly straight forward to expand into SLAM, and rs_slam. If you are interested in running Google Cartographer with the depth camera and the Jackal, you should start with the package: jackal-cartographer-navigation. As you look into this option for mapping, you will discover that you need to publish a /scan topic to get Cartographer to work, whereas the depth camera publishes a pointcloud message. The pointcloud to laserscan wiki gets into this, and ultimately, you'll need to work with the pointcloud to laserscan repo. Once you prove to yourself that you can get a scan topic being published as the camera is running, you can move to integrate everything into Cartographer.