ROS 2 in Kria kv260 with Petalinux 2021.2

Adding ROS 2 to Kria kv260 PetaLinux 2021.2 build

In this tutorial, we are going to see how to add ROS 2 to a Petalinux project. This tutorial is based on PetaLinux 2021.2 and since at the time of writing this project, there isn't any Kria KV260 Starter Kit BSP available for PetaLinux 2021.2 we made a custom BSP starting from the old version Kria K26 Starter Kit 2021.1. This process of how to create 2021.2 Starter Kit BSP is not documented yet, it will be available soon but if you want more information you can contact me or read the README inside the 2021.1 Starter Kit BSP.

We will skip the step of installing PetaLinux onto your Linux system, there are a lot of resources available online and we will go directly to what have been the steps to be able to launch a minimum publish/subscriber example using ROS 2 in the Kria board:

1. Create the project from BSP

Run the following commands to create the PetaLinux template from the custom BSP.

$ petalinux-create -t project -s xilinx-k26-starterkit-v2021.2-custom.bsp -n petalinux-ros2
$ cd petalinux-ros2
$ petalinux-config --silentconfig

2. Adding meta-ros layer to PetaLinux

If you are interested in what is included inside meta-ros or to know more about the installation process you can read the official guide.

• First, we need to install the needed dependencies:

sudo apt-get install gawk wget git-core diffstat unzip texinfo gcc-multilib \
        build-essential chrpath socat cpio python python3-pip python3-pexpect \
        xz-utils debianutils iputils-ping \
        python3-git python3-jinja2 libegl1-mesa libsdl1.2-dev xterm \
        g++-multilib locales lsb-release python3-distutils time
sudo locale-gen en_US.utf8

• Second, inside the project-spec folder, you need to download meta-ros layer.

git clone https://github.com/ros/meta-ros.git -b gatesgarth 
cd meta-ros
git checkout 56cf4de00280451bf5a36f55acbec32b9f22f841

Here we are using gatesgarth branch because PetaLinux is based on this release as we can see inside project-spec/meta-user/conf/layer.conf.

LAYERSERIES_COMPAT_meta-user = "gatesgarth"

Then we move to the 56cf4de commit point in history. But why to this point?

We move here because in the next commit to this, 0e373be, they did a change of all the ''_'' with '':'' that is not supported in PetaLinux 2021.2 openembedded core layer and throws an error when adding the layers to the Petalinux project because it doesn't know how to parse this ":".

• Third, before using the PetaLinux config interface we need to add in build/conf/bblayers.conf the next two variables:

# define the ROS 2 Yocto target release
ROS_OE_RELEASE_SERIES = "gatesgarth"

# define ROS 2 distro
ROS_DISTRO = "rolling"

We will be adding rolling ROS 2 distro to our images but if you want you can add here foxy or galactic. Depending on which one you use you might need to change the imported layers below.

This is a little bit ugly because if you do petalinux-build -x mrproper this file will be erased and you will need to set these variables again but we haven't found how to do it in another way.

• Forth, for configuring the layer path in the PetaLinux build system you need to move to your PetaLinux project directory, and add the layer path in the below config option.

petalinux-config --> Yocto Settings --> User Layers 
--> (${PROOT}/project-spec/meta-ros/*) user layer 0
--> ()    user layer 1

You need to exactly add the next 4 layers:

${PROOT}/project-spec/meta-ros/meta-ros-backports-hardknott
${PROOT}/project-spec/meta-ros/meta-ros-common
${PROOT}/project-spec/meta-ros/meta-ros2
${PROOT}/project-spec/meta-ros/meta-ros2-rolling

Ad the end you will have something like this:

After saving you should see now how are they added to build/conf/bblayers.conf

3. Create a custom image containing ROS 2 packages

For this, you need to define a petalinux-image-minimal.bbappend in your PetaLinux project:

cd project-spec/meta-user
mkdir -p recipes-images/images; 
cd recipes-images/images
touch petalinux-image-minimal.bbappend

And add this content:

require ${COREBASE}/../meta-petalinux/recipes-core/images/petalinux-image-minimal.bb

SUMMARY = "A image including a bare-minimum installation of ROS 2 and including some basic pub/sub examples. It includes two DDS middleware implementations, FastDDS and Cyclone DDS"
DESCRIPTION = "${SUMMARY}"

inherit ros_distro_${ROS_DISTRO}
inherit ${ROS_DISTRO_TYPE}_image

ROS_SYSROOT_BUILD_DEPENDENCIES = " \
    ament-lint-auto \
    ament-cmake-auto \
    ament-cmake-core \
    ament-cmake-cppcheck \
    ament-cmake-cpplint \
    ament-cmake-export-definitions \
    ament-cmake-export-dependencies \
    ament-cmake-export-include-directories \
    ament-cmake-export-interfaces \
    ament-cmake-export-libraries \
    ament-cmake-export-link-flags \
    ament-cmake-export-targets \
    ament-cmake-gmock \
    ament-cmake-gtest \
    ament-cmake-include-directories \
    ament-cmake-libraries \
    ament-cmake \
    ament-cmake-pytest \
    ament-cmake-python \
    ament-cmake-ros \
    ament-cmake-target-dependencies \
    ament-cmake-test \
    ament-cmake-version \
    ament-cmake-uncrustify \
    ament-cmake-flake8 \
    ament-cmake-pep257 \
    ament-copyright \
    ament-cpplint \
    ament-flake8 \
    ament-index-python \
    ament-lint-cmake \
    ament-mypy \
    ament-package \
    ament-pclint \
    ament-pep257 \
    ament-pycodestyle \
    ament-pyflakes \
    ament-uncrustify \
    ament-xmllint \
    cmake \
    eigen3-cmake-module \
    fastcdr \
    fastrtps-cmake-module \
    fastrtps \
    git \
    gmock-vendor \
    gtest-vendor \
    pkgconfig \
    python-cmake-module \
    python3-catkin-pkg \
    python3-empy \
    python3 \
    python3-nose \
    python3-pytest \
    rcutils \
    rmw-implementation-cmake \
    rosidl-cmake \
    rosidl-default-generators \
    rosidl-generator-c \
    rosidl-generator-cpp \
    rosidl-generator-dds-idl \
    rosidl-generator-py \
    rosidl-parser \
    rosidl-runtime-c \
    rosidl-runtime-cpp \
    rosidl-typesupport-c \
    rosidl-typesupport-cpp \
    rosidl-typesupport-fastrtps-cpp \
    rosidl-typesupport-interface \
    rosidl-typesupport-introspection-c \
    rosidl-typesupport-introspection-cpp \
    foonathan-memory-vendor \
    libyaml-vendor \
"

IMAGE_INSTALL_append = " \
    ros-base \
    examples-rclcpp-minimal-action-client \
    examples-rclcpp-minimal-action-server \
    examples-rclcpp-minimal-client \
    examples-rclcpp-minimal-composition \
    examples-rclcpp-minimal-publisher \
    examples-rclcpp-minimal-service \
    examples-rclcpp-minimal-subscriber \
    examples-rclcpp-minimal-timer \
    examples-rclcpp-multithreaded-executor \
    examples-rclpy-executors \
    examples-rclpy-minimal-action-client \
    examples-rclpy-minimal-action-server \
    examples-rclpy-minimal-client \
    examples-rclpy-minimal-publisher \
    examples-rclpy-minimal-service \
    examples-rclpy-minimal-subscriber \
    demo-nodes-cpp \
    demo-nodes-cpp-rosnative \
    demo-nodes-py \
    cyclonedds \
    rmw-cyclonedds-cpp \
    tmux \
    python3-argcomplete \
    glibc-utils \
    localedef \
    rt-tests \
    stress \
    xrt-dev \
    xrt \
    zocl \
    opencl-headers-dev \
    opencl-clhpp-dev \
    ${ROS_SYSROOT_BUILD_DEPENDENCIES} \
"

IMAGE_LINGUAS = "en-us"
GLIBC_GENERATE_LOCALES = "en_US.UTF-8"

4. Build PetaLinux project

Before building the last thing you need to do is to add in project-spec/meta-user/conf/petalinuxbsp.conf the next line:

SIGGEN_UNLOCKED_RECIPES += "gcc-cross-aarch64"

This solves some problems with building the image.

Now, you are finally ready to build the image with:

petalinux-build

5. Create a bootable image for Kria kv26

Once the image is created you can go to images/linux folder and create your sd-card image:

petalinux-package --wic --bootfiles "ramdisk.cpio.gz.u-boot boot.scr Image system.dtb"

This will create a petalinux-sdimage.wic that you can flash using balenaEtcher.

6. Run ROS 2 minimal publisher/subscriber examples

If you connect to your board using ssh and use the next commands:

• Terminal 1

$ source /usr/bin/ros_setup.bash
$ ros2 run examples_rclcpp_minimal_publisher publisher_lambda

• Terminal 2

$ ros2 node list
/minimal_publisher
$ ros2 node info /minimal_publisher
/minimal_publisher
  Subscribers:
    /parameter_events: rcl_interfaces/msg/ParameterEvent
  Publishers:
    /parameter_events: rcl_interfaces/msg/ParameterEvent
    /rosout: rcl_interfaces/msg/Log
    /topic: std_msgs/msg/String
  Service Servers:
    /minimal_publisher/describe_parameters: rcl_interfaces/srv/DescribeParameters
    /minimal_publisher/get_parameter_types: rcl_interfaces/srv/GetParameterTypes
    /minimal_publisher/get_parameters: rcl_interfaces/srv/GetParameters
    /minimal_publisher/list_parameters: rcl_interfaces/srv/ListParameters
    /minimal_publisher/set_parameters: rcl_interfaces/srv/SetParameters
    /minimal_publisher/set_parameters_atomically: rcl_interfaces/srv/SetParametersAtomically
  Service Clients:

  Action Servers:

  Action Clients:
$ ros2 topic list
/parameter_events
/rosout
/topic

And finally,

$ source /usr/bin/ros_setup.bash
$ ros2 run examples_rclcpp_minimal_subscriber subscriber_lambda

A video of how this works:

Thank you for reading! I hope you find this tutorial useful and that you can start using ROS 2 with this new version of PetaLinux. Cheers!

Update 1

This project also works for Ultra96v2 board. You can skip step 1 and start from step 2 . You only need an Ultra96v2 PetaLinux project.

To create one you can follow Mario Bergeron Appendix 2- Rebuilding the Design guide and then change the PetaLinux project.

Here is how it works ROS 2 in the Ultra96v2 and Vitis-AI 2.0.

Update 2

If you have problems fetching rolling recipes, please use galactic or foxy.