By Toradex秦海

1). 簡介

基于類似NXP iMX8這樣性能強勁的ARM平臺處理器，越來越多的工業(yè)智能/機器人應用比如AGV/AMR產(chǎn)品控制器在ARM平臺上面實現(xiàn)，在這個過程中不可避免的就涉及到將機器人應用開發(fā)框架移植到ARM平臺來運行，因此本文就著重示例基于Ycoto Project/Openembedded環(huán)境，將ROS（Robot Operating System）編譯集成到嵌入式Linux中運行。

ROS是一種為機器人應用設計的分布式處理框架，集成了大量相關庫和工具，目的是為了提高機器人應用開發(fā)時代碼復用率, 目前ROS已經(jīng)發(fā)展到ROS2，這里就演示將ROS2最新版本Foxy集成到iMX8 Linux BSP中。

本文的演示的平臺來自于Toradex Apalis iMX8 ARM嵌入式平臺，這是一個基于NXP iMX8QM ARM處理器，支持Cortex-A72+A53和Coretex-M4架構的計算機模塊平臺。

2). 準備

a). Apalis iMX8QM 4GB WB IT ARM核心版配合Ioxra 載板，連接調(diào)試串口UART1（載板X22）到開發(fā)主機方便調(diào)試。

3). Apalis iMX8 Ycoto Linux 集成ROS2編譯環(huán)境配置和部署

a). Apalis iMX8 Ycoto Linux 通過Ycoto/Openembedded 框架編譯，具體的配置方法請參考這里，首先下載好針對Apalis iMX8適用的基于Ycoto Dunfeil版本的BSP 5.x.y編譯環(huán)境。

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$ repo init -u https://git.toradex.com/toradex-manifest.git -b dunfell-5.x.y -m tdxref/default.xml

$ repo sync

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b). 下載meta-ros 和meta-python2 layer到上面下載好的ycoto環(huán)境

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$ cd …/oe-core/layers/

### fetch meta-ros layer

$ git clone -b dunfell https://github.com/ros/meta-ros.git

### fetch meta-phthon2 layer

$ git clone -b dunfell https://github.com/YoeDistro/meta-python2.git

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c). 配置編譯環(huán)境，添加編譯ROS2 Foxy版本需要的相關layer，由于目前ycoto 編譯ROS還無法支持圖形界面相關，因此也要在編譯環(huán)境中將相關的package排除出去。

./ 添加環(huán)境變量

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### generate init env

$ cd …/oe-core/

$ source export

### add new env

$ export ROS_OE_RELEASE_SERIES="dunfell"

### make new env valid with bitbake

$ export BB_ENV_EXTRAWHITE="$BB_ENV_EXTRAWHITE ROS_OE_RELEASE_SERIES"

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./ 修改 build/conf/bblayers.conf 文件

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   ${TOPDIR}/../layers/meta-freescale-distro \

   ${TOPDIR}/../layers/meta-toradex-demos \

   ${TOPDIR}/../layers/meta-qt5 \

+  ${TOPDIR}/../layers/meta-python2 \

+  ${TOPDIR}/../layers/meta-ros/meta-ros2-foxy \

+  ${TOPDIR}/../layers/meta-ros/meta-ros2 \

+  ${TOPDIR}/../layers/meta-ros/meta-ros-common \

+  ${TOPDIR}/../layers/meta-ros/meta-ros-backports-gatesgarth \

   \

   \

   ${TOPDIR}/../layers/meta-toradex-distro \

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./ 修改 build/conf/local.conf 文件

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### modify machine setting to apalis imx8

MACHINE ?= "apalis-imx8"

### add ros-core only or ros-world packagegroup for all ros2-foxy packages

IMAGE_INSTALL_append = " packagegroup-ros-world"

### blacklist below packages which currently not supported in ycoto compilation

### detailed impact package refer to \ /layers/meta-ros/meta-ros2-foxy/conf/ros-distro/include/foxy/ros-distro-recipe-blacklist.inc and \ layers/meta-ros/meta-ros2-foxy/recipes-core/packagegroups/packagegroup-ros-world-foxy.bb files

ROS_WORLD_SKIP_GROUPS = " opengl qt5 qt5-widgets pyqt5 qt-gui-cpp x11 ffmpeg webots-python-modules java libomp connext gazebo coinor-libipopt gurumdds ignition doosan-robot2 clang launch pugixml lanelet2-traffic-rules mongodb kobuki-ftdi ros1"

### define package graphviz version

PREFERRED_VERSION_graphviz = "2.40.1%"

### accept freescale EULA license

ACCEPT_FSL_EULA = "1"

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./ 修改 layers/meta-ros/meta-ros2-foxy/recipes-bbappends/osqp-vendor/osqp-vendor_0.0.2-1.bbappend 文件修復當前版本中的bug

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-SRCREV_osqp = "c536acf012d071eed3529e0147afdd419348362a"

+SRCREV_osqp = "36ad83aed022e714c2fda1f13138443150435994"

 SRCREV_qdldl = "12d56ee6b9494efee1da1e1dc6e7ac9c226f9ccf"

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d). 編譯image和SDK

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# compile Reference-Minimal image

$ bitbake bitbake tdx-reference-minimal-image

# compile Reference-Multimedia image

$ bitbake bitbake tdx-reference-multimedia-image

# compile SDK

bitbake tdx-reference-multimedia-image -c populate_sdk

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e). Ycoto Linux image部署

參考這里通過Toradex Easy installer將上面編譯好的image更新部署到模塊，目前最新季度發(fā)布版本為Ycoto Linux V5.2，這里使用Reference-Minimal BSP image進行測試

4). ROS2 Foxy測試

a). 修改ROS初始化相關腳本權限，增加執(zhí)行權限

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root@apalis-imx8:~# chmod +x /etc/profile.d/ros/*

root@apalis-imx8:~# ls -al /etc/profile.d/ros/setup.sh                                       

-rwxr-xr-x    1 root     root          4372 Mar  9  2018 /etc/profile.d/ros/setup.sh

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b). 通過下面命令進行ROS2 Foxy簡單測試

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### check network connection

root@apalis-imx8:~# ping lge.com

### source setup script to export env

root@apalis-imx8:~# source /usr/bin/ros_setup.sh

### ros topic print

root@apalis-imx8:~# ros2 topic list

/parameter_events

/rosout

### ros interface print

root@apalis-imx8:~# ros2 interface list -m

……

### test

root@apalis-imx8:~# (sleep 5; ros2 topic pub /chatter std_msgs/String "data: Hello world") &

[1] 826

root@apalis-imx8:~# ros2 topic echo /chatter

publisher: beginning loop

publishing #1: std_msgs.msg.String(data='Hello world')

publishing #2: std_msgs.msg.String(data='Hello world')

publishing #3: std_msgs.msg.String(data='Hello world')

publishing #4: std_msgs.msg.String(data='Hello world')

data: Hello world

---

publishing #5: std_msgs.msg.String(data='Hello world')

data: Hello world

……

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5). 總結(jié)

本文基于NXP iMX8嵌入式平臺演示了通過Ycoto Project/Openembedded框架將ROS2 Foxy集成到嵌入式Linux BSP中，目前meta-ros layer除了Foxy，還支持ROS1 melodic，ROS1 noetic，ROS2 dashing，ROS2 eloquent，其他ROS版本可以自行根據(jù)所需要的layer不同而適應修改后編譯。

參考文獻

https://github.com/ros/meta-ros/wiki/OpenEmbedded-Build-Instructions

https://developer.toradex.cn/knowledge-base/board-support-package/openembedded-core