Difference between revisions of "ROS2"

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==<font color='blue'>GitHub</font>==
+
==<font color='blue'>About</font>==
https://github.com/bmwcarit/meta-ros.git
+
Use ROS2 in Elphel single or multi-camera systems. The cameras are 10393 system boards based on Xilinx Zynq, ARM.
  
<font color='red'>https://github.com/erlerobot/meta-ros2</font> ?
+
==<font color='blue'>Goals</font>==
 +
<font color='green'>'''Notes:'''
 +
* Controlling and initializing of multi-camera systems is already implemented using PHP API (autocampars.php), Python and lighttpd.
 +
* Using ROS2 is intended to simplify/standardize the above.
 +
* Using ROS2 is intended to make cameras compatible with other hardware supported by ROS1/2.
 +
</font>
  
 +
Having ROS2 cross-compiled and installed on each camera:
 +
* '''Initialize cameras in a pre-defined multi-camera system''' - sync and sequence critical init
 +
* '''Control multiple cameras from any camera of the system''' - parameters, recording
 +
* '''Control multiple cameras from a PC''' (with ROS2 for PC installed).
 +
* '''Control multiple cameras from a network device''' (w/o ROS2 installed, but with a browser) - by accessing a web server running on a camera interfaced with ROS2 of the camera. Can use nodejs or just lighttpd+php.
  
==<font color='blue'>ROS2 General Notes</font>==
+
==<font color='blue'>Status</font>==
===Notes===
+
Development
* SROS is Secure ROS or something
+
==<font color='blue'>News</font>==
===Useful links===
+
* [2019/01/03] Updated the cross-compiled version from '''ardent''' to '''bouncy'''. PC was already at '''bouncy''' because rclnodejs will work with '''bouncy''' only (not yet compatible with '''crystal''').  
* [http://docs.erlerobotics.com/robot_operating_system/ros2/tutorials/tutorial_10 Tutorials ErleRobotics]
+
Updated because ''bouncy'' would not 'see' ''ardent'' nodes & services and vice versa.
* [https://github.com/intel/ros2_intel_realsense Intel RealSense]
 
* [https://index.ros.org/doc/ros2/Ament-Tutorial/ Ament tutorial] - will not work for PC because it's outdated, will work in Yocto
 
* [https://index.ros.org/doc/ros2/Colcon-Tutorial/ Colcon tutorial] - this one worked for PC
 
* [https://discourse.ros.org/t/suggestions-for-std-srvs/1079/16 STD-SRVS '''discussion'''] & [https://github.com/ros2/examples/issues/4 ROS2 examples(?)]
 
* [https://discourse.ros.org/search?q=meta-ros%20order%3Alatest About meta-ros]
 
  
===PC workflow===
+
==<font color='blue'>Interfaces</font>==
* Install ROS2 - will get installed to '''/opt/ros/<name>'''
+
ROS2 nodes communicate over:
* Terminal setup:
+
* '''1 GigE LAN''' or (possibly) '''wifi''' (camera1-camera2..N, pc-camera1..N, pc1-pc2..M)
source /opt/ros/bouncy/setup.bash
+
* within a single device
or
+
<font color='green'>'''Notes:'''
source /opt/ros/bouncy/local_setup.bash
+
* image sensors, IMS (or GPS & IMU), any other sensors are attached to cameras via a custom interface or USB, with appropriate driver support.
 
+
* normally cameras in the system are synced with a custom trigger cable - this is setup over network
* Create a workspace
+
* any device attached to PC?
* Create some packages inside or clone - they have a [https://github.com/dirk-thomas/vcstool vcs tool] to clone all repos from a text file.
+
</font>
* Install [https://colcon.readthedocs.io/en/released/user/quick-start.html colcon]
 
* Then build with colcon
 
* Packages will not get installed to /opt/ros/bouncy/... Instead they will stay in their folders.
 
* To use a package:
 
source /opt/ros/bouncy/setup.bash
 
source ~/ros2_ws/some-package/install/local_setup.bash
 
ros2 pkg list
 
then run anything in this terminal
 
* Python scripts can live anywhere - just run them from that sourced terminal
 
* [https://erlerobotics.gitbooks.io/erle-robotics-python-gitbook-free/udp_and_tcp/a_simple_tcp_client_and_server.html Good book about UDP?]
 
 
 
===Embedded workflow===
 
* Use meta-ros in yocto
 
* Go for ROS2 recipes. Use as examples.
 
* The build system in Yocto is '''ament''' - which is one generation older then '''colcon'''
 
* Here there's no workspace - packages do get installed somewhere
 
* Need to  
 
export AMENT_PREFIX_PATH=/usr
 
* Python scripts can live anywhere - because ROS2 populates /usr/lib/...
 
* Service formats are too few - for a simple "Request string - Response string" server need to add new srv.
 
 
 
===Docker===
 
docker pull osrf/ros2:bouncy-desktop
 
docker run -i -t osrf/ros2:bouncy-desktop
 
...no network, no colcon, no ament...
 
  
 
==<font color='blue'>ROS2 on Zynq</font>==
 
==<font color='blue'>ROS2 on Zynq</font>==
Cross-compiled and installed in Yocto
 
  
===Other links===
+
===Installation===
* [http://design.ros2.org/articles/ros_on_dds.html ROS on DDS]
+
* For Embedded Linux (but not Ubuntu Distro) use [https://github.com/bmwcarit/meta-ros.git meta-ros.git]. What about <font color='red'>[https://github.com/erlerobot/meta-ros2 meta-ros2]</font>?
<font size='2'>...
+
<font color='green'><s>'''TODO:''' Include [https://github.com/bmwcarit/meta-ros.git meta-ros.git] in [https://git.elphel.com/Elphel/elphel393 elphel393] build system.</s></font>
if you are concerned about latency, like for soft real-time, you can basically tune DDS to be just a UDP blaster. In another scenario you might need something that behaves like TCP, but needs to be more
 
tolerant to long dropouts, and with DDS all of these things can be controlled by changing the QoS parameters.
 
...</font>
 
  
* [http://www.eprosima.com/index.php/resources-all/performance/40-eprosima-fast-rtps-performance FastRTPS benchmarks]
+
<font color='green'>'''DONE:''' included a forked version [https://github.com/okdzhimiev/meta-ros/ okdzhimiev/meta-ros]</font>
* [http://docs.eprosima.com/en/latest/advanced.html FastRTPS max message size]
 
* [https://wiki.ros.org/Services Request-Response is done with '''service''']. Format [https://wiki.ros.org/srv srv]
 
  
===Build===
+
====Include meta-ros to elphel393====
 
* Add path to bblayers.conf
 
* Add path to bblayers.conf
 
* Add to "IMAGE_INSTALL_append" of core-image-elphel393.bb:
 
* Add to "IMAGE_INSTALL_append" of core-image-elphel393.bb:
  packagegroup-ros2-world \
+
  <font size='2'>packagegroup-ros2-world \</font>
  
<font color='green'>'''Notes:'''
+
===Notes===
* -</font>
+
* Cross-compilation for ARM
 +
* ROS2 for python populates '''/usr/lib/python3.5/site-packages/''' so python scripts can live anywhere.
 +
* For command line apps, like ''ros2 ...'', if AMENT_PREFIX_PATH is not set then:
 +
<font size='1' color='red'>'''OSError: Environment variable 'AMENT_PREFIX_PATH' is not set or empty'''</font>
 +
* Useful commands (command line):
 +
<font size='2'>export AMENT_PREFIX_PATH=/usr</font>
  
===Work===
+
<font size='2'>ros2 pkg list
 +
ros2 node list
 +
ros2 srv list
 +
ros2 srv show std_srvs/Trigger
 +
ros2 msg list
 +
ros2 msg show std_msgs/String</font>
  
====Available packages====
+
===Demos===
* SSH session:
+
====talker-listener cpp====
root@elphel393:~# export AMENT_PREFIX_PATH=/usr
+
  <font size='2'>''# terminal 1:''
root@elphel393:~# ros2 pkg list
+
  export AMENT_PREFIX_PATH=/usr
  <font size='1'>builtin_interfaces
+
  ros2 run demo_nodes_cpp talker
demo_nodes_cpp
+
example_interfaces
+
''# terminal 2:''
geometry_msgs
+
  export AMENT_PREFIX_PATH=/usr
rcl
+
  ros2 run demo_nodes_cpp listener</font>
rcl_interfaces
 
rclcpp
 
rclpy
 
rcutils
 
rmw
 
rmw_fastrtps_cpp
 
rosidl_cmake
 
rosidl_generator_c
 
rosidl_generator_cpp
 
rosidl_parser
 
rosidl_typesupport_interface
 
rosidl_typesupport_introspection_c
 
rosidl_typesupport_introspection_cpp
 
sensor_msgs</font>
 
 
 
====Test Talker and Listener====
 
* SSH session 1:
 
  root@elphel393:~# export AMENT_PREFIX_PATH=/usr
 
  root@elphel393:~# ros2 run demo_nodes_cpp talker
 
* SSH session 2:
 
  root@elphel393:~# export AMENT_PREFIX_PATH=/usr
 
  root@elphel393:~# ros2 run demo_nodes_cpp listener
 
  
<font color='green'>'''Notes:'''</font>
+
===Workflow===
* It populates '''/usr/lib/python3.5/site-packages/''' so python scripts can be pretty much standalone
+
* Use example recipes from [https://github.com/bmwcarit/meta-ros.git meta-ros.git]
* <font color='green'>If AMENT_PREFIX_PATH is not set (only for command line apps) then:</font>
+
* ''bitbake package-name'', check output and logs in the poky build tree
<font size='1'>Traceback (most recent call last):
+
* List package in core-image-elphel393.bb's ''IMAGE_INSTALL_append''
  File "/usr/bin/ros2", line 11, in <module>
+
<font color='green'>'''TODO:'''
    load_entry_point('ros2cli==0.4.0', 'console_scripts', 'ros2')()
+
* Add ''target-scp'' and an example empty recipe</font>
  File "/usr/lib/python3.5/site-packages/ros2cli/cli.py", line 64, in main
 
    rc = extension.main(parser=parser, args=args)
 
  File "/usr/lib/python3.5/site-packages/ros2run/command/run.py", line 59, in main
 
    executable_name=args.executable_name)
 
  File "/usr/lib/python3.5/site-packages/ros2run/api/__init__.py", line 30, in get_executable_path
 
    paths = get_executable_paths(package_name=package_name)
 
  File "/usr/lib/python3.5/site-packages/ros2pkg/api/__init__.py", line 41, in get_executable_paths
 
    prefix_path = get_prefix_path(package_name)
 
  File "/usr/lib/python3.5/site-packages/ros2pkg/api/__init__.py", line 34, in get_prefix_path
 
    prefix_path = get_package_prefix(package_name)
 
  File "/usr/lib/python3.5/site-packages/ament_index_python/packages.py", line 49, in get_package_prefix
 
    content, package_prefix = get_resource('packages', package_name)
 
  File "/usr/lib/python3.5/site-packages/ament_index_python/resources.py", line 37, in get_resource
 
    for path in get_search_paths():
 
  File "/usr/lib/python3.5/site-packages/ament_index_python/search_paths.py", line 30, in get_search_paths
 
    "Environment variable '{}' is not set or empty".format(AMENT_PREFIX_PATH_ENV_VAR))
 
<font color='red'>'''OSError: Environment variable 'AMENT_PREFIX_PATH' is not set or empty'''</font></font>
 
  
 
==<font color='blue'>ROS2 on PC</font>==
 
==<font color='blue'>ROS2 on PC</font>==
* [https://index.ros.org/doc/ros2/Linux-Install-Debians/ Linux-Install-Debians]
+
===Installation===
 +
* Google and follow the [https://index.ros.org/doc/ros2/ general instructions].
  
<font color='green'>'''Notes:'''
+
===Notes===
* '''apt install ros-bouncy-desktop''' available in 18.04, n/a in 16.04
+
* Switched to installing from a ''fat'' archive
* '''apt install ros-ardent-desktop''' available in 16.04</font>
+
* Terminal setup:
 +
<font size='2'>''source /path/setup.bash''</font>
  
==<font color='blue'>ROS1</font>==
+
===Workflow===
 +
* Create a workspace
 +
* Create some packages inside or clone - they have a [https://github.com/dirk-thomas/vcstool vcs tool] to clone all repos from a text file.
 +
* Install [https://colcon.readthedocs.io/en/released/user/quick-start.html colcon]
 +
* Then build with colcon
 +
* New packages will not get installed anywhere. They live in their folders.
 +
* To use a package:
 +
<font size='2'>source ~/ros2_ws/some-package/install/setup.bash
 +
ros2 pkg list
 +
then run anything in this terminal</font>
 +
* Python scripts can live anywhere - just run them from that sourced terminal
  
===Build===
+
==<font color='blue'>ROS2 in Docker</font>==
<font color='red'>'''Won't build'''</font>
+
  docker pull osrf/ros2:bouncy-desktop
<font size='1'>Build Configuration:
+
  docker run -i -t osrf/ros2:bouncy-desktop
BB_VERSION          = "1.37.0"
+
  No network, no colcon, no ament...
BUILD_SYS            = "x86_64-linux"
 
NATIVELSBSTRING      = "universal"
 
  TARGET_SYS          = "arm-poky-linux-gnueabi"
 
MACHINE              = "elphel393"
 
DISTRO              = "poky"
 
DISTRO_VERSION      = "2.4+snapshot-20181204"
 
TUNE_FEATURES        = "arm armv7a vfp neon cortexa9"
 
TARGET_FPU          = "softfp"
 
meta               
 
meta-poky           
 
meta-yocto-bsp      = "HEAD:72867393fe2004ab9f0ee23eb09a975c82938b9e"
 
meta-ezynq          = "rocko:046de13c06cc248b725cb7b9928f35d4a369b50f"
 
  meta-elphel393      = "rocko:0cea9b9b8776f0fe725316f1be1501396c95feb4"
 
meta-ros            = "HEAD:72068b17e4192b51e09c8dc633805a35edac8701"
 
meta-xilinx-bsp      = "HEAD:a18947c20dba2c0c38db8bde1ad4684995df4bbd"
 
  meta-oe             
 
meta-python         
 
meta-networking     
 
meta-webserver      = "HEAD:34aa4c3202b427f59f843dc43a4e1afda4f81d13"</font>
 
  
* Error 1:
+
==<font color='blue'>ROS2 General Notes</font>==
** ROS_USE_PYTHON3 = "yes"
+
===Notes===
** IMAGE_INSTALL += "roslaunch"
+
* SROS is Secure ROS or something
  
<font size='1'>NOTE: Resolving any missing task queue dependencies
+
===Useful links===
ERROR: Nothing RPROVIDES 'python3-pycrypto' (but /home/oleg/GIT/elphel393_rocko_clean_install/meta/meta-ros/recipes-devtools/python/python3-paramiko_1.16.0.bb RDEPENDS on or otherwise requires it)
 
NOTE: Runtime target 'python3-pycrypto' is unbuildable, removing...
 
Missing or unbuildable dependency chain was: ['python3-pycrypto']
 
NOTE: Runtime target 'python3-paramiko' is unbuildable, removing...
 
Missing or unbuildable dependency chain was: ['python3-paramiko', 'python3-pycrypto']
 
NOTE: Runtime target 'roslaunch' is unbuildable, removing...
 
Missing or unbuildable dependency chain was: ['roslaunch', 'python3-paramiko', 'python3-pycrypto']
 
ERROR: Required build target 'core-image-elphel393' has no buildable providers.
 
Missing or unbuildable dependency chain was: ['core-image-elphel393', 'roslaunch', 'python3-paramiko', 'python3-pycrypto']</font>
 
  
* Successful build:
+
* [http://docs.erlerobotics.com/robot_operating_system/ros2 ErleRobotics Tutorials on ROS2] - very useful
** IMAGE_INSTALL += "roslaunch"
 
  
<font size='1'>NOTE: Resolving any missing task queue dependencies
+
* [https://index.ros.org/doc/ros2/Ament-Tutorial/ Ament tutorial] - build system for new packages
ERROR: Nothing RPROVIDES 'python3-pycrypto' (but /home/oleg/GIT/elphel393_rocko_clean_install/meta/meta-ros/recipes-devtools/python/python3-paramiko_1.16.0.bb RDEPENDS on or otherwise requires it)
+
** works and supported in meta-ros
NOTE: Runtime target 'python3-pycrypto' is unbuildable, removing...
+
** will not work for PC because repo hashes moved on?
Missing or unbuildable dependency chain was: ['python3-pycrypto']
 
NOTE: Runtime target 'python3-paramiko' is unbuildable, removing...
 
Missing or unbuildable dependency chain was: ['python3-paramiko', 'python3-pycrypto']
 
NOTE: Runtime target 'roslaunch' is unbuildable, removing...
 
Missing or unbuildable dependency chain was: ['roslaunch', 'python3-paramiko', 'python3-pycrypto']
 
ERROR: Required build target 'core-image-elphel393' has no buildable providers.
 
Missing or unbuildable dependency chain was: ['core-image-elphel393', 'roslaunch', 'python3-paramiko', 'python3-pycrypto']</font>
 
  
 +
* [https://index.ros.org/doc/ros2/Colcon-Tutorial/ Colcon tutorial] - newest build system for new packages
 +
** works for PC, even in 16.04
 +
** not supported in meta-ros (as of 2018/12/07)
 +
** [https://colcon.readthedocs.io/en/released/user/how-to.html#build-only-a-single-package-or-selected-packages colcon docs]
  
* Error 2:
+
* [https://discourse.ros.org/search?q=meta-ros%20order%3Alatest About meta-ros] and [https://discourse.ros.org/search?q=meta-ros2%20order%3Alatest about meta-ros2] - are they merged?
** <font color='red'>Seems like '''rostopic''' causes:</font>
 
<font size='1'>ERROR: python-imaging-1.1.7-r5 do_package_qa: QA Issue: python-imaging: The compile log indicates that host include and/or library paths were used.
 
          Please check the log '/home/oleg/GIT/elphel393_rocko_clean_install/poky/build/tmp/work/cortexa9-neon-poky-linux-gnueabi/python-imaging/1.1.7-r5/temp/log.do_compile' for more information. [compile- host-path]
 
ERROR: python-imaging-1.1.7-r5 do_package_qa: QA run found fatal errors. Please consider fixing them.
 
ERROR: python-imaging-1.1.7-r5 do_package_qa: Function failed: do_package_qa
 
ERROR: Logfile of failure stored in: /home/oleg/GIT/elphel393_rocko_clean_install/poky/build/tmp/work/cortexa9-neon-poky-linux-gnueabi/python-imaging/1.1.7-r5/temp/log.do_package_qa.19425
 
ERROR: Task (/home/oleg/GIT/elphel393_rocko_clean_install/meta/meta-openembedded/meta-python/recipes-devtools/python/python-imaging_1.1.7.bb:do_package_qa) failed with exit code '1'</font>
 
 
potential links:
 
  https://github.com/intel-aero/meta-intel-aero/issues/81
 
  https://github.com/bmwcarit/meta-ros/issues/395
 
  
removed python3-imaging from '''rosbag''' - everything builds but then not really working.
+
Networking:
  
  with '''ROS_USE_PYTHON3 = "yes"''' stopped at finding an appropriate '''python-pycrypto''' lib
+
* [http://design.ros2.org/articles/ros_on_dds.html ROS on DDS]
 +
  <font size='2'>...
 +
if you are concerned about latency, like for soft real-time, you can basically tune DDS to be just a UDP blaster. In another scenario you might need something that behaves like TCP, but needs to be more
 +
tolerant to long dropouts, and with DDS all of these things can be controlled by changing the QoS parameters.
 +
...</font>
  
===Work===
+
* [http://www.eprosima.com/index.php/resources-all/performance/40-eprosima-fast-rtps-performance FastRTPS benchmarks]
* <font color='red'>'''Won't work'''</font>
+
* [http://docs.eprosima.com/en/latest/advanced.html FastRTPS max message size]
 +
* [https://erlerobotics.gitbooks.io/erle-robotics-python-gitbook-free/udp_and_tcp/a_simple_tcp_client_and_server.html Good book about UDP?]
  
** There's no '''rosrun''' (does not exist?)
+
ROS2 Services:
  
** SSH session 1:
+
* [https://wiki.ros.org/Services Request-Response is done with '''service''']. Format [https://wiki.ros.org/srv srv]
*** Add to /etc/hosts:
+
* [https://discourse.ros.org/t/suggestions-for-std-srvs/1079/16 STD-SRVS '''discussion'''] & [https://github.com/ros2/examples/issues/4 ROS2 examples(?)]
127.0.0.1 elphel393.localdomain elphel393
 
*** Export vars:
 
export ROS_ROOT=/opt/ros
 
export ROS_DISTRO=indigo
 
export ROS_PACKAGE_PATH=/opt/ros/indigo/share
 
export PATH=$PATH:/opt/ros/indigo/bin
 
export LD_LIBRARY_PATH=/opt/ros/indigo/lib
 
export PYTHONPATH=/opt/ros/indigo/lib/python2.7/site-packages
 
export ROS_MASTER_URI=http://localhost:11311
 
export CMAKE_PREFIX_PATH=/opt/ros/indigo
 
touch /opt/ros/indigo/.catkin
 
*** Roscore
 
roscore
 
  
 +
===Reference ROS repos===
 +
* [https://github.com/inertialsense/inertial_sense_ros.git inertial_sense_ros.git] - cpp
 +
* [https://github.com/intel/ros2_intel_realsense.git ros2_intel_realsense.git] - cpp
 +
* [https://github.com/ros-drivers/axis_camera.git axis_camera.git] - python
 +
* [https://github.com/bmwcarit/meta-ros.git meta-ros.git] - layer for Yocto
  
** SSH session 2:
+
==<font color='blue'>ROS1</font>==
root@elphel393:~# rosnode list
+
<font color='red'>'''Won't build'''</font>. [[ROS1|More info]].
  <font size='1'>/rosout</font>
 
root@elphel393:~# rospack list
 
  <font size='1'>cpp_common /opt/ros/indigo/share/cpp_common
 
  genmsg /opt/ros/indigo/share/genmsg
 
  genpy /opt/ros/indigo/share/genpy
 
  rosbag /opt/ros/indigo/share/rosbag
 
  rosbag_storage /opt/ros/indigo/share/rosbag_storage
 
  rosclean /opt/ros/indigo/share/rosclean
 
  rosconsole /opt/ros/indigo/share/rosconsole
 
  roscpp /opt/ros/indigo/share/roscpp
 
  roscpp_serialization /opt/ros/indigo/share/roscpp_serialization
 
  roscpp_tutorials /opt/ros/indigo/share/roscpp_tutorials
 
  rosgraph /opt/ros/indigo/share/rosgraph
 
  rosgraph_msgs /opt/ros/indigo/share/rosgraph_msgs
 
  roslaunch /opt/ros/indigo/share/roslaunch
 
  roslib /opt/ros/indigo/share/roslib
 
  roslz4 /opt/ros/indigo/share/roslz4
 
  rosmaster /opt/ros/indigo/share/rosmaster
 
  rosnode /opt/ros/indigo/share/rosnode
 
  rosout /opt/ros/indigo/share/rosout
 
  rospack /opt/ros/indigo/share/rospack
 
  rosparam /opt/ros/indigo/share/rosparam
 
  rospy /opt/ros/indigo/share/rospy
 
  rospy_tutorials /opt/ros/indigo/share/rospy_tutorials
 
  rostime /opt/ros/indigo/share/rostime
 
  rostopic /opt/ros/indigo/share/rostopic
 
  std_msgs /opt/ros/indigo/share/std_msgs
 
  topic_tools /opt/ros/indigo/share/topic_tools
 
  xmlrpcpp /opt/ros/indigo/share/xmlrpcpp</font>
 

Latest revision as of 16:00, 3 January 2019

About

Use ROS2 in Elphel single or multi-camera systems. The cameras are 10393 system boards based on Xilinx Zynq, ARM.

Goals

Notes:

  • Controlling and initializing of multi-camera systems is already implemented using PHP API (autocampars.php), Python and lighttpd.
  • Using ROS2 is intended to simplify/standardize the above.
  • Using ROS2 is intended to make cameras compatible with other hardware supported by ROS1/2.

Having ROS2 cross-compiled and installed on each camera:

  • Initialize cameras in a pre-defined multi-camera system - sync and sequence critical init
  • Control multiple cameras from any camera of the system - parameters, recording
  • Control multiple cameras from a PC (with ROS2 for PC installed).
  • Control multiple cameras from a network device (w/o ROS2 installed, but with a browser) - by accessing a web server running on a camera interfaced with ROS2 of the camera. Can use nodejs or just lighttpd+php.

Status

Development

News

  • [2019/01/03] Updated the cross-compiled version from ardent to bouncy. PC was already at bouncy because rclnodejs will work with bouncy only (not yet compatible with crystal).

Updated because bouncy would not 'see' ardent nodes & services and vice versa.

Interfaces

ROS2 nodes communicate over:

  • 1 GigE LAN or (possibly) wifi (camera1-camera2..N, pc-camera1..N, pc1-pc2..M)
  • within a single device

Notes:

  • image sensors, IMS (or GPS & IMU), any other sensors are attached to cameras via a custom interface or USB, with appropriate driver support.
  • normally cameras in the system are synced with a custom trigger cable - this is setup over network
  • any device attached to PC?

ROS2 on Zynq

Installation

TODO: Include meta-ros.git in elphel393 build system.

DONE: included a forked version okdzhimiev/meta-ros

Include meta-ros to elphel393

  • Add path to bblayers.conf
  • Add to "IMAGE_INSTALL_append" of core-image-elphel393.bb:
packagegroup-ros2-world \

Notes

  • Cross-compilation for ARM
  • ROS2 for python populates /usr/lib/python3.5/site-packages/ so python scripts can live anywhere.
  • For command line apps, like ros2 ..., if AMENT_PREFIX_PATH is not set then:
OSError: Environment variable 'AMENT_PREFIX_PATH' is not set or empty
  • Useful commands (command line):
export AMENT_PREFIX_PATH=/usr
ros2 pkg list
ros2 node list
ros2 srv list
ros2 srv show std_srvs/Trigger
ros2 msg list
ros2 msg show std_msgs/String

Demos

talker-listener cpp

# terminal 1:
export AMENT_PREFIX_PATH=/usr
ros2 run demo_nodes_cpp talker

# terminal 2:
export AMENT_PREFIX_PATH=/usr
ros2 run demo_nodes_cpp listener

Workflow

  • Use example recipes from meta-ros.git
  • bitbake package-name, check output and logs in the poky build tree
  • List package in core-image-elphel393.bb's IMAGE_INSTALL_append

TODO:

  • Add target-scp and an example empty recipe

ROS2 on PC

Installation

Notes

  • Switched to installing from a fat archive
  • Terminal setup:
source /path/setup.bash

Workflow

  • Create a workspace
  • Create some packages inside or clone - they have a vcs tool to clone all repos from a text file.
  • Install colcon
  • Then build with colcon
  • New packages will not get installed anywhere. They live in their folders.
  • To use a package:
source ~/ros2_ws/some-package/install/setup.bash
ros2 pkg list
then run anything in this terminal
  • Python scripts can live anywhere - just run them from that sourced terminal

ROS2 in Docker

docker pull osrf/ros2:bouncy-desktop
docker run -i -t osrf/ros2:bouncy-desktop 
No network, no colcon, no ament...

ROS2 General Notes

Notes

  • SROS is Secure ROS or something

Useful links

  • Ament tutorial - build system for new packages
    • works and supported in meta-ros
    • will not work for PC because repo hashes moved on?
  • Colcon tutorial - newest build system for new packages
    • works for PC, even in 16.04
    • not supported in meta-ros (as of 2018/12/07)
    • colcon docs

Networking:

... 
if you are concerned about latency, like for soft real-time, you can basically tune DDS to be just a UDP blaster. In another scenario you might need something that behaves like TCP, but needs to be more 
tolerant to long dropouts, and with DDS all of these things can be controlled by changing the QoS parameters.
...

ROS2 Services:

Reference ROS repos

ROS1

Won't build. More info.