ras_ros_low_level_systems

A bridge between vessels' low level systems and ros, running on the onboard computers.

Use:

Manually turning on the core on-board modules is done from a terminal within the network: Connect to a ship:

ssh [email protected]

where titoneri-darkblue.local can also be replaced by its IP address.

Starting the main modules is done by:

cd ras_ros_low_level_systems; docker compose up

Benchmark setup

Installation of OS on on-board computer

Install a recent linux distribution. You can choose a more minimalistic OS, or one with conveniencies such as a desktop GUI.

For Raspberry Pi's consider using the linux raspberry-pi-imager program from the software center. It's quite convenient. I used Ubuntu-Server-24.04LTS64bit image for RPI4B

Consider compatibilities with this distribution. Docker can give you flexibility in deploying modules, but if you want to run something specific, check if it is supported (e.g. check support for your envisioned ros distibution).

Configure the network to connect to lab routers or VPN.

Configure SSH connection. Make sure you can ssh with a terminal from another PC to the device using ssh [email protected] (default user is commonly 'ubuntu' or 'pi' depending on the OS you chose) (a helpful guide )

Set username to ras with new password. For example with:

ssh [email protected]

make ras user and add to sudo group

sudo adduser ras; sudo adduser ras sudo

exit and relog as ras

ssh [email protected]

sudo deluser --remove-home ubuntu

(optional) Change the device name to something sensible and preferably unique (to allow login by name later)

sudo nano /etc/hostname

(optional) Enable access by hostname (e.g. ssh [email protected]) by

sudo nano /etc/systemd/resolved.conf

and setting MulticastDNS=yes

(optional) Set access keys between device and your pc for easy access. From your host pc that wants access:

ssh-copy-id [email protected]

Install Docker

snap install docker
sudo groupadd docker # Give docker sudo access. 
sudo usermod -aG docker ${USER} # Add current user to docker group. Might need relog to apply.

(optional) install network debug tools

sudo apt install net-tools

Configure WiFi

In 2024 we set it up as follows. For connecting initially ethernet is a convenient option. ssh onto a ship computer and configure using netplan. once logged in edit the network setup file, or create it if it does not exist:

sudo nano /etc/netplan/50-cloud-init.yaml

Watch indentation. Working settings were as follows. Copy/edit required parts

# This file is generated from information provided by the datasource.  Changes
# to it will not persist across an instance reboot.  To disable cloud-init's
# network configuration capabilities, write a file
# /etc/cloud/cloud.cfg.d/99-disable-network-config.cfg with the following:
# network: {config: disabled}
network:
    ethernets:
        eth0:
            dhcp4: true
            optional: true
    version: 2
    wifis:
        wlan0:
            access-points:
                NETGEAR21:
                    password: fill_in_actual_password_here_without_quotes
            dhcp4: true
            optional: true

Then reboot or use ```sudo netplan apply``

Prepare modules

All major components are stored in the ras homefolder (/home/ras). Add the configuration file for this drone, where we set the major settings for this device.

sudo nano ~/ras_entrypoint.sh

Fill in the following configuration:

#!/bin/bash
source vessel_id.env
export RAS_GH_USERNAME="ras-delft-user"
export RAS_GH_KEY="<FILL IN ras-delft-user pull/write GITHUB KEY>"
export RMW_IMPLEMENTATION="rmw_fastrtps_cpp"

set vessel specific configuration

echo 'export VESSEL_ID=RAS_TN_DB' > vessel_id.env

Make sure this gets called upon bash startup by adding it to .bashrc with nano or

echo "source /home/ras/ras_entrypoint.sh" >> ~/.bashrc

Get the repository with main dockerfiles in the home folder ('cd ~')

git clone https://github.com/RAS-Delft/ras_ros_low_level_systems

Navigate to folder and update submodules

cd ras_ros_low_level_systems; git submodule update --init --recursive

Build and run the docker containers

docker compose build

Microcontroller

This device is responsible for executing desired actuation. Flashing the microcontroller can be done with starting the set-up docker container that

• autodetects usb port (defaults to device with Arduino in the name)
• Installs flash software (platformIO) and required libraries in temporary container
• flashes the microcontroller C++ software that is included in this repository, and exits.

Navigate to the microcontroller driver folder

cd /home/ras/ras_ros_low_level_systems/microcontroller_driver

Build the docker container. Let the installer container do its thing

docker compose build; docker compose up

GNSS setup

The GNSS system from Emlid does need some setup on a new device. Connect it and we should be able to identify its name when it pops up in the latest usb events

Check if leds on the receiver are all on. Check if you can already access the network adress to the gnss:

ping 192.168.2.15

Alternatively, ifconfig lists the network to the receiver as a semi random name, but similar to enx7ee4720f03c4.

If it is not pingable or listed, we try finding the network device:

sudo dmesg | grep -i usb

...
[ 2254.571711] usb 1-1.1: Product: ReachM2
[ 2254.571725] usb 1-1.1: Manufacturer: Emlid
[ 2254.584195] cdc_ether 1-1.1:1.0 usb0: register 'cdc_ether' at usb-0000:01:00.0-1.1, CDC Ethernet Device, ee:57:0b:ce:14:b3
[ 2254.592001] cdc_acm 1-1.1:1.2: ttyACM0: USB ACM device
[ 2254.624507] cdc_ether 1-1.1:1.0 enxee570bce14b3: renamed from usb0

Our devicename here is enxee570bce14b3 which we want to use later on.

Alternatively it could be listed with: (here enxdaa7eb798e93)

ip link list

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: enp1s0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc mq state DOWN mode DEFAULT group default qlen 1000
    link/ether 80:ee:73:f1:5e:e2 brd ff:ff:ff:ff:ff:ff
4: wlp2s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP mode DORMANT group default qlen 1000
    link/ether 70:66:55:b1:da:0a brd ff:ff:ff:ff:ff:ff
5: enxdaa7eb798e93: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP mode DEFAULT group default qlen 1000
    link/ether da:a7:eb:79:8e:93 brd ff:ff:ff:ff:ff:ff

Activate the connection if state=DOWN

sudo ip link set enxee570bce14b3 up

Assign an IP address to the Raspberry Pi's network interface. This IP should be in the same subnet as your USB device, but not conflicting with default receiver adress:192.168.2.15. For example, assign 192.168.2.1

sudo ifconfig enxee570bce14b3 192.168.2.1 netmask 255.255.255.0 up

Finally you should be able to access the emlid (that is by default reachable on 192.168.2.15 . You might need to reboot for settings to apply):

ping 192.168.2.15