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a hard real-time ROS?

asked 2011-03-07 14:54:59 -0500

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Hi All,

I'm new to ROS and don't know much about it. Is ROS suitable for hard real-time applicaitons?

Has anyone tried to run ROS on a hard real-time Linux, say, Xenomai or RTAI? Or does it make sense to do so?

Thanks,

Zhu

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answered 2011-03-07 15:44:33 -0500

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For this kind of requirements we provide Orocos. We provide a integration with ROS in our repository allowing to do your low level real-time control with Orocos and still make use of high level algorithms like the navigation stack from ROS. This kind of setup was already demonstrated on multiple robots like the RoboEarth Amigo platform, the Kuka Youbot, ...

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What real-time mechanism Orocos provide? Hard real-time or Soft real-time? Thank you~
sam gravatar imagesam ( 2011-09-28 04:15:00 -0500 )edit
it as real-time as your kernel allows you to be, it differs if you are using regular linux, patched kernel, xenomai ...
KoenBuys gravatar imageKoenBuys ( 2011-09-28 11:22:36 -0500 )edit
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answered 2012-03-27 03:04:08 -0500

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I just started working at KULeuven, home of OROCOS but a different department. Everyone I have met here who is doing hard real-time is using Ubuntu with a xenomai kernel, ROS just as a package manager/build system, and writing all of their code as OROCOS components and running them in the orocos deployer.

I haven't met anyone doing inter-op between Orocos and ROS yet; I read that you can send signals between the two environments with some work, but their workflows and toolsets are mostly orthogonal. (i.e. Try using rosnode to list what orocos components you have instantiated or listing running ros nodes in the orocos deployer)

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Interaction is quite seamless, tool-sets live next to each other. However not all code is written as an Orocos component or executed from the deployer. Most of us use both ROS and Orocos however.

KoenBuys gravatar imageKoenBuys ( 2012-03-27 09:04:14 -0500 )edit

Hello. I would like to use also ROS for some real -time data analysis. I do not have experience in that and would like to use the data provided from ROS nodes for some real time analysis. Is there any help on this?

Astronaut gravatar imageAstronaut ( 2013-05-05 20:55:09 -0500 )edit
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answered 2016-11-05 07:16:28 -0500

gvdhoorn gravatar image

In addition to all the work in ROS2 towards making real-time ROS a reality, the presentation by Jan Carstensen at ROSCon16 this year might also be of interest to users.

RTROS – A real-time extension to the Robot Operating System: slides, recording.

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Any idea if it will be released?

Dben gravatar imageDben ( 2016-12-20 09:25:04 -0500 )edit

Afaik yes, but it could take some time.

If you want to help: get in touch with the author(s), and express your interest.

gvdhoorn gravatar imagegvdhoorn ( 2016-12-20 09:44:18 -0500 )edit
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We are in the final stages of releasing RTROS.

Jan Carstensen gravatar imageJan Carstensen ( 2016-12-21 02:11:34 -0500 )edit

Hi @Jan Carstensen :). Thanks for the update.

gvdhoorn gravatar imagegvdhoorn ( 2016-12-21 02:21:44 -0500 )edit

while i understand what a real-time (soft/hard) system is, i still cannot provide myself a real world example of a robot using ROS that cannot adequately perform with native ROS. can someone shed some light?

JadTawil gravatar imageJadTawil ( 2018-09-26 09:31:12 -0500 )edit

A surgical robot that performs open heart surgery while the heart is beating. You will want deterministic execution for that, as you'll need to be able to guarantee that the system always does what it is supposed to do down to the lowest levels. Just being 'fast enough' is not sufficient.

gvdhoorn gravatar imagegvdhoorn ( 2018-09-26 09:42:37 -0500 )edit

A less 'exotic' example: synchronising the motion of multiple industrial robots all holding the same workpiece. Without deterministic execution and communication, that is impossible (or at least: is very much simplified if you do have both).

But anything for which the behaviour of the system ..

gvdhoorn gravatar imagegvdhoorn ( 2018-09-26 09:44:10 -0500 )edit

.. should be predictable (so not just run it and see what happens) almost requires deterministic execution.

gvdhoorn gravatar imagegvdhoorn ( 2018-09-26 09:44:43 -0500 )edit

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Asked: 2011-03-07 14:54:59 -0500

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Last updated: Nov 05 '16