ROS2 on arm architecture

Setup the development environment

The normal setup described in the following link is required for the cross-compilation -> https://github.com/ros2/ros2/wiki/Linux-Development-Setup

Get the source

Create a workspace and clone all repos:

mkdir -p ros2_ws/src
cd ros2_ws
wget https://raw.githubusercontent.com/ros2/ros2/release-latest/ros2.repos
wget https://raw.githubusercontent.com/ros2-for-arm/ros2/master/ros2-for-arm.repos
wget https://raw.githubusercontent.com/ros2-for-arm/ros2/master/aarch64_toolchainfile.cmake
vcs-import src < ros2.repos
vcs-import src < ros2-for-arm.repos

Get an aarch64 toolchain and export it

sudo apt install g++-aarch64-linux-gnu gcc-aarch64-linux-gnu

# If you are not using a custom toolchain
export PATH="<path to toolchain>/bin:$PATH"
export CROSS_COMPILE=aarch64-linux-gnu-

Remove Python support and ignore optional packages

Packages that depend on Python or other libraries that are not part of the package itself are ignored. The following command disables the build of such packages by adding an empty file called COLCON_IGNORE in their base directory:

touch \
  src/ros-perception/laser_geometry/COLCON_IGNORE \
  src/ros/resource_retriever/COLCON_IGNORE \
  src/ros2/geometry2/COLCON_IGNORE \
  src/ros2/urdf/COLCON_IGNORE \
  src/ros2/demos/COLCON_IGNORE \
  src/ros2/kdl_parser/COLCON_IGNORE \
  src/ros2/ros1_bridge/COLCON_IGNORE \
  src/ros2/rmw_connext/COLCON_IGNORE \
  src/ros2/orocos_kinematics_dynamics/COLCON_IGNORE \
  src/ros2/examples/rclpy/COLCON_IGNORE \
  src/ros2/robot_state_publisher/COLCON_IGNORE \
  src/ros2/rviz/COLCON_IGNORE \
  src/ros2/rcl/rcl/test/COLCON_IGNORE \
  src/ros2/urdfdom/COLCON_IGNORE \
  src/ros2/rclpy/COLCON_IGNORE \
  src/ros2/rosidl_typesupport_opensplice/COLCON_IGNORE \
  src/ros2/system_tests/COLCON_IGNORE \
  src/ros2/rosidl_python/COLCON_IGNORE \
  src/ros2/rmw_opensplice/COLCON_IGNORE \
  src/ros2/rosidl_typesupport_connext/COLCON_IGNORE \
  src/ros2/rcl_interfaces/test_msgs/COLCON_IGNORE

Note: If you require any of these packages, you can still cross-compile them if you pre-build their dependencies. You can set CMAKE_SYSROOT pointing to a root filesystem containing the pre-built dependencies. For more information, see CMAKE_SYSROOT documentation

Trigger a build

colcon build \
  --symlink-install \
  --cmake-force-configure \
  --cmake-args \
    --no-warn-unused-cli \
    -DCMAKE_TOOLCHAIN_FILE=`pwd`/aarch64_toolchainfile.cmake \
    -DTHIRDPARTY=ON \
    -DBUILD_TESTING:BOOL=OFF \
    -DCMAKE_BUILD_RPATH="`pwd`/build/poco_vendor/poco_external_project_install/lib/;`pwd`/build/libyaml_vendor/libyaml_install/lib/"

Installation

Once the compilation is done you will have to move the generated libraries (install/<Package Name>/lib) in your target filesystem. Get all the libraries using cp `find . -name "*.so*"` <destination_directory>. On your target, place the libraries into the /lib directory (default search path used when a binary is launched). Alternatively, set the LD_LIBRARY_PATH environment variable to the directory containing the libraries.