Setting Up Networking

First Connection

In order to set up Ridgeback to connect to your own wireless network, you will first need to ssh access Ridgeback’s computer from you computer over a wired connection:

  1. Configure your computer to have a static IP address on the 192.168.131.x subnet, e.g. 192.168.131.100.

  2. Connect an ethernet cable between Ridgeback’s computer and your computer.

  3. ssh into Ridgeback’s computer from your computer. In your computer’s terminal, run:

ssh administrator@192.168.131.1

  1. Enter the default password clearpath. You should now be logged into Ridgeback as the administrator user.

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.

  1. To change the password to log into your Ridgeback, you can use the passwd command. In Ridgeback’s computer’s terminal, run:

passwd

  1. You will be prompted 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 Ridgeback, you can reconfigure the Ridgeback’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.

Connecting to Wifi Access Point

Ridgeback uses netplan for configuring its wired and wireless interfaces. You can configure netplan so that Ridgeback’s computer can connect to your own wireless network:

  1. In Ridgeback’s computer’s terminal, create the file /etc/netplan/60-wireless.yaml.

  2. Populate the file /etc/netplan/60-wireless.yaml with the following:

network:
  wifis:
    # Replace WIRELESS_INTERFACE with the name of the wireless network device, e.g. wlan0 or wlp3s0
    # Fill in the SSID and PASSWORD fields as appropriate.  The password may be included as plain-text
    # or as a password hash.  To generate the hashed password, run
    #   echo -n 'WIFI_PASSWORD' | iconv -t UTF-16LE | openssl md4 -binary | xxd -p
    # If you have multiple wireless cards you may include a block for each device.
    # For more options, see https://netplan.io/reference/
    WIRELESS_INTERFACE:
      optional: true
      access-points:
        SSID_GOES_HERE:
          password: PASSWORD_GOES_HERE
      dhcp4: true
      dhcp4-overrides:
        send-hostname: true

  1. Modify the variables in the file /etc/netplan/60-wireless.yaml with the details of your wireless network.

  2. Save the file /etc/netplan/60-wireless.yaml.

  3. Apply your new netplan configuration and bring up your wireless connection. In Ridgeback’s computer’s terminal, run:

sudo netplan apply

  1. Verify that Ridgeback successfully connected to your wireless network. In Ridgeback’s computer’s terminal:

ip a

This will show all active connections and their IP addresses, including the connection to your wireless network, and the IP address assigned to Ridgeback’s computer.

Remote ROS Connection

It is useful to connect your computer to the Ridgeback’s ROS master, particularly if you want to use ROS desktop tools to interface with the Ridgeback:

  1. Ensure both your computer and Ridgeback’s computer are connected to the same wireless network. This process will also work for a wired connection, but for the purposes of establishing a remote ROS connection, it makes sense to use a wireless connection.

  2. On your computer, set the ROS_MASTER_URI and ROS_IP environment variables. The ROS_MASTER_URI environment variable tells your computer how to find the ROS master on the Ridgeback’s computer. The ROS_IP environment variable tells processes on the Ridgeback’s computer how to find your computer. In your computer’s terminal, create a script in your computer’s home directory called remote-Ridgeback.sh with the following contents:

export ROS_MASTER_URI=http://<Ridgeback_HOSTNAME>:11311  # Ridgeback's computer's hostname
export ROS_IP=<COMPUTER_IP>                             # Your computer's wireless IP address

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

<Ridgeback_IP> <Ridgeback_HOSTNAME>

  1. When ready to communicate remotely with Ridgeback’s computer from your computer, you can source the remote-Ridgeback.sh script; thus, defining those two key environment variables in the present context. In your computer’s terminal, run:

source remote-Ridgeback.sh

  1. You should be able to now be able to access RidgebackS’s ROS data from your computer, such as the list of ROS nodes, the list of ROS topics, the ROS messages being published on ROS topics, and the frequencies/rates at which the ROS messages are being published at. In terminal on your computer, run:

rosnode list
rostopic list
rostopic hz <ROS_TOPIC>
rostopic echo <ROS_TOPIC>

  1. Once you’ve verified the basics from the prompt, try launching some of the standard visual ROS tools. In terminal on your computer, run:

roslaunch Ridgeback_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, in terminal on your computer, run:

rqt

Configuring Network Bridge

Ridgeback is configured to bridge its physical ethernet ports together. This allows any ethernet port to be used as a connection to the internal 192.168.131.1/24 network for connecting sensors, diagnostic equipment, or manipulators, or for connecting the Ridgeback to the internet for the purposes of installing updates.

In the unlikely event you must modify Ridgeback’s ethernet bridge, you can do so by editing the configuration file found at /etc/netplan/50-clearpath-bridge.yaml:

# Configure the wired ports to form a single bridge
# We assume wired ports are en* or eth*
# This host will have address 192.168.131.1
network:
version: 2
renderer: networkd
ethernets:
bridge_eth:
  dhcp4: no
  dhcp6: no
  match:
    name: eth*
bridge_en:
  dhcp4: no
  dhcp6: no
  match:
    name: en*
bridges:
br0:
  dhcp4: yes
  dhcp6: no
  interfaces: [bridge_en, bridge_eth]
  addresses:
    - 192.168.131.1/24

This file will create a bridged interface called br0 that will have a static address of 192.168.131.1, but will also be able to accept a DHCP lease when connected to a wired router. By default, all network ports named en* and eth* are added to the bridge. This includes all common wired port names, such as: eth0, eno1, enx0123456789ab, enp3s0, etc.

To include/exclude additional ports from the bridge, edit the match fields, or add additional bridge_* sections with their own match fields, and add those interfaces to the interfaces: [bridge_en, bridge_eth] line near the bottom of the file.

We do not recommend changing the static address of the bridge to be anything other than 192.168.131.1; changing this may cause sensors that communicate over ethernet (e.g. lidars, cameras, GPS arrays) from working properly.