Setting Up Heron’s Network

Heron is equipped with a Microhard wireless module to allow wireless connectivity. Depending on the confguration ordered, this can be configured to operate as a wireless access point on the robot itself, or it can be configured to connect to a portable base station that remains on shore while the robot operates.

Setup

If this is your first time unboxing Heron, makse sure that the robot’s wireless antennas are firmly connected to the robot. The connections for the antennas have rubber seals in them to ensure they remain water resistant. If the antennas are loose this may allow water ingress, which can inhibit the proper function of the robot.

Changing the Default Password

Note

All Clearpath robots ship from the factory with their login password set to clearpath. Upon receipt of your robot we recommend changing the password.

To change the password to log into your robot, run the

passwd

command. This will prompt you to enter the current password, followed by the new password twice. While typing the passwords in the passwd prompt there will be no visual feedback (e.g. “*” characters).

To further restrict access to your robot you can reconfigure the robot’s SSH service to disallow logging in with a password and require SSH certificates to log in. This tutorial covers how to configure SSH to disable password-based login.

Network Configuration on the Heron

Depending on when your heron shipped, the networking may be configured in one of two possible ways: using /etc/network/interfaces or using netplan. Most older Herons will use the interfaces file, while newer ones have switched to netplan, as this has become the standard method of configuring networks in more recent releases of Ubuntu.

Note

Heron’s network can operate in two modes: with a base station, or as a stand-alone access point.

Please see Networking with a Base Station or Networking with Heron as a Wireless Access Point for further details on how to operate Heron in each of these modes.

Network configuration with Netplan

Netplan replaced the older ifupdown and /etc/network/interfaces method of configuring network interfaces in Ubuntu 18.04. It is possible to revert to the older method if desired, though this is not recommended. For instructions on the older network configration method, see below.

Netplan uses yaml files to configure the network interfaces of the robot. On Heron, this file is located at /etc/netplan/50-clearpath-bridge.yaml. The contents of the file should look like this:

# Configure the wired ports to form a single bridge
# We assume wired ports are enp* or eth*
# This host will have address 192.168.131.1
network:
  version: 2
  renderer: networkd
  ethernets:
    bridgeports:
      match:
        name: (enp*)|(eth*)
      dhcp4: no
      dhcp6: no
  bridges:
    br0:
      dhcp4: no
      interfaces: [bridgeports]
      addresses:
        - 192.168.131.1/24
      nameservers:
        addresses:
          - 8.8.8.8
          - 8.8.4.4
      gateway4: 192.168.131.50

The file above is for a Heron with a base station. If your robot does not have a base station the gateway4 and nameservers keys may be omitted.

Network configuration with /etc/network/interfaces

Note

If your Heron is already configured to use netplan we do not advise rolling back to interfaces; we have had reports of connectivity problems with base stations on Herons running Ubuntu 18.04 when using the interfaces file to configure the network.

On Ubuntu 18.04 you can revert to the older /etc/network/interfaces method of configuring the network interfaces by running

sudo apt-get install ifupdown

The network interfaces configuration file, located at /etc/network/interfaces should contain the following:

auto lo br0
iface lo inet loopback

# Bridge together physical ports on machine, assign standard Clearpath Robot IP.
iface br0 inet static
  bridge_ports      regex (eth.*)|(en.*)
  address           192.168.131.1
  netmask           255.255.255.0
  bridge_maxwait    0
  # if you do not have a base station, omit the following
  gateway           192.168.131.50
  dns-nameservers   8.8.8.8  8.8.4.4

Note on Wicd

The wireless networking manager wicd is frequently installed on Clearpath robots. While this application is not needed on Heron under most circumstances, some users choose to install it.

wicd can also manage wired interfaces, which can cause problems with the static networking configuration defined above. If your robot has wicd installed, ensure that it is not managing the wired network by running

wicd-curses

Press shift+P to open wicd’s preferences, use the arrow keys to scroll down to the Wired Interface and delete any text in that field. Save the preferences and close wicd-curses.

Remote ROS Connection

To use ROS desktop tools, you’ll need your computer to be able to connect to Heron’s ROS master. This can be a tricky process, but we’ve tried to make it as simple as possible.

In order for the ROS tools on your computer to talk to Heron, they need to know two things:

  • How to find the ROS master, which is set in the ROS_MASTER_URI environment variable, and

  • How processes on the other computer can find your computer, which is the ROS_IP environment variable.

The suggested pattern is to create a file in your home directory called remote-heron.sh with the following contents:

export ROS_MASTER_URI=http://cpr-heron-0001:11311  # Heron's hostname
export ROS_IP=10.25.0.102                          # Your laptop's wireless IP address

If your network doesn’t already resolve Heron’s hostname to its wireless IP address, you may need to add a corresponding line to your computer’s /etc/hosts file:

10.25.0.101 cpr-heron-0001

Then, when you’re ready to communicate remotely with Heron, you can source that script like so, thus defining those two key environment variables in the present context.

source remote-heron.sh

Now, when you run commands like rostopic list, rostopic echo, rosnode list, and others, the output you see should reflect the activity on Heron’s ROS master, rather than on your own machine. Once you’ve verified the basics (list, echo) from the prompt, try launching some of the standard visual ROS tools:

roslaunch heron_viz view_robot.launch
rosrun rqt_robot_monitor rqt_robot_monitor
rosrun rqt_console rqt_console

If there are particular rqt widgets you find yourself using a lot, you may find it an advantage to dock them together and then export this configuration as the default RQT perspective. Then, to bring up your standard GUI, you can simply run:

rqt

Legacy Connectivity

Older Herons may have shipped with a combination Wifi/Bluetooth module, for example an Intel Centrino Advanced-N 6235, instead of the Microhard.

Connecting to Wifi Access Point

Heron’s standard wireless network manager is wicd. To connect to an access point in your lab, run:

wicd-curses

You should see a browsable list of networks which the robot has detected. Use arrow keys to select the one you would like to connect to, and then press the right arrow to configure it. You can enter your network’s password near the bottom of the page, and note that you must select the correct encryption scheme; most modern networks use WPA1/2 Passphrase, so if that’s you, make sure that option is selected. You also likely want to select the option to automatically reconnect to this network, so that Heron will be there for you on your wireless automatically in the future.

When you’re finished, press F10 to save, and then C to connect.

Wicd will tell you in the footer what IP address it was given by your lab’s access point, so you can now log out, remove the network cable, and reconnect over wireless. When you’ve confirmed that all this is working as expected, close up Heron’s chassis.