[PYTHON] I tried to build an environment of Ubuntu 20.04 LTS + ROS2 with Raspberry Pi 4

Introduction

--raspi4 + ubuntu20.04 + Let's build an environment for ROS (foxy). --Completely a memorandum. --Updated - 2020/06/16

table of contents

1. Install Ubuntu 20.04 LTS on Raspberry Pi 4
2. Install ROS2 on Ubuntu 20.04 LTS
3. Try running the test code

1. Install Ubuntu 20.04 LTS on Raspberry Pi 4

What you have prepared

• Raspberry Pi 4 computer Model B 4GB RAM --micro SD card (16GB this time)
• PC(mac or windows or linux)

procedure

(1) Install Raspberry Pi Imager

-Download to my PC from Official Page --For mac, you can easily get it with homebrew - brew cask install raspberry-pi-imager

(2) Write an image to a microSD card using Raspberry Pi Imager

--Launch Raspberry Pi Imager

--Select ubuntu 20.04 LTS for operating system ――Let's take 64bit as a place to install ROS2

--Specify SD card and press WRITE --Remove the SD card and finish

(3) Start raspi4

-Insert the SD card with the image written in (2) into raspi and start it (connect the power supply) ――It takes time for the first time ...?

• log in --Default user name ubuntu --Default password ubuntu
• change the password

(4) Host name, time zone, IP address settings

[Reference site](https://denor.jp/ubuntu-20-04-focal-fossa%E3%81%AE%E5%88%9D%E6%9C%9F%E8%A8%AD%E5%AE % 9A-ip% E3% 82% A2% E3% 83% 89% E3% 83% AC% E3% 82% B9% E3% 80% 81% E3% 83% 9B% E3% 82% B9% E3% 83 % 88% E5% 90% 8D% E7% AD% 89)

Host name setting

sudo hostnamectl set-hostname ooo

Time zone setting

sudo timedatectl set-timezone Asia/Tokyo

IP address setting

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

--Reference file --192.168.xxx.1 is the IP of the router --192.168.xxx.yyy is the IP of raspi

python

network:
    ethernets:
        eth0:
            dhcp4: false
            addresses: [192.168.xxx.yyy/24]
            gateway4: 192.168.xxx.1
            nameservers:
                addresses: [192.168.xxx.1]
    version: 2

--After editing, reflect the settings on netplan

sudo netplan apply
sudo reboot

2. Install ROS2 on Ubuntu 20.04 LTS

--There are various versions -Previous version --This time, we will use ROS2 foxy that supports ubuntu 20.04 LTS.

--Basically, if you copy and paste according to Installation procedure on the official page, it will end. .. Should be. --This time, I went to ** Install argcomplete (optional) ** on the official page.

procedure

(1) Locale setup

--Set the OS character code to UTF8

sudo locale-gen en_US en_US.UTF-8
sudo update-locale LC_ALL=en_US.UTF-8 LANG=en_US.UTF-8
export LANG=en_US.UTF-8

(2) Setup Sources --Add ROS2 apt repository

sudo apt update && sudo apt install curl gnupg2 lsb-release
curl -s https://raw.githubusercontent.com/ros/rosdistro/master/ros.asc | sudo apt-key add -
sudo sh -c 'echo "deb http://packages.ros.org/ros2/ubuntu `lsb_release -cs` main" > /etc/apt/sources.list.d/ros2-latest.list'

(3) Install ROS2 packages

--There are two types, base and desktop, but this time install base

sudo apt update
sudo apt install ros-foxy-ros-base

(4) Environment settings

source /opt/ros/foxy/setup.bash
echo "source /opt/ros/foxy/setup.bash" >> ~/.bashrc

(5) Install argcomplete

• Not required --You will be able to complete ROS2-related command lines with tab.

sudo apt install python3-argcomplete

3. Try running the test code

--This time, execute the code for python

procedure

(1) Create a workspace and get the test code,

--The test code (rclcpp) for C language is also installed, so I will delete it this time.

mkdir -p ~/ros2/src
cd ~/ros2
git clone https://github.com/ros2/examples src/examples
cd ~/ros2/src/examples/
git checkout $ROS_DISTRO
rm -rf rclcpp 

(2) Install colcon (build tool)

-Installation reference page -Page about colcon --About colcon --A build tool that can be built even if both versions of ROS1 and ROS2 are mixed. --The ROS1 package is built by calling ** catkin **, and ROS2 by calling ** ament **.

sudo apt install python3-colcon-common-extensions

(3) Build the package

cd ~/ros2
colcon build --symlink-install

(4) Environment settings

source ~/ros2/install/setup.bash
echo "source ~/ros2/install/setup.bash" >> ~/.bashrc

(5) Operation check

--Publisher on terminal (1)

ros2 run examples_rclpy_minimal_publisher publisher_member_function

--Subscriber on terminal (2)

ros2 run examples_rclpy_minimal_subscriber subscriber_member_function

By the way, fantastic! !! !!

--Terminal (1) Publisher

--Terminal (2) Subscriber

--Click here for the test code executed this time

-Publisher side

-Subscriber side

Reference page