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ROSI and Universal Robot for an industrial application

asked 2018-11-14 11:56:17 -0600

reynot gravatar image

updated 2018-11-15 06:11:03 -0600

I have been looking at ROS and ROSI with the intention of using a Universal Robot (UR5) and ROS in a commercial application.

I have a fresh Ubuntu Xenial 16.04.05 install with ROS Kinetic.

I have been reading "ROS Programming : Building Powerful Robots master" and other publications as well as the other material and the online documentation.

My first target was to control a simulated UR5 using the MoveIt, Gazebo, RViz and my test application using the Moveit C++ API. I have had quite a painful ride but I understand the ROS framework now but drivers and compatibility seem to be giving me issues. My current implementation fails when I try to execute move(), a known problem.

I have 2 questions :

(1) UR5 and ROS The universal robot package ( http://wiki.ros.org/universal_robot ) is shown as experimental and use in production systems not recommended. This greatly concerns me as a non starter, we have this powerful framework available but experimental drivers? Is this assertion reasonable or is this driver package really not suitable for production? Am I missing something or are universal robots not considered for production systems? Before I put in more effort, I wanted to confirm the suitability of my configuration?

(2) Outdated drivers I believe the universal_robot ur_driver is the cause of my issues, and is no longer recommended. It seems ur_modern_driver is recommended ( https://answers.ros.org/question/2545... . The ur_modern_driver adds ros_control required for move() support when simulated. Why has the ur_modern_driver not replaced the ur_driver? Surely everyone will fall at the first hurdle and have to find the above thread?

================================================================================ UPDATE following response from @gvdhoorn

Thanks for your reply, I appreciate you taking the time.

I have several responses, in reply to your questions.

(1) Experimental status

Thanks for the detailed explanation, it is hard to understand how the ROS framework comes together without your comments. Understood that it depends on what functionality and hardware I chose to use, will determine what test coverage it has had. It essence I have to try it out myself but I am reassured there are production systems on the platform I am proposing and an active community willing to support.

(2) The ur_modern_driver adds ros_control required for move() support when simulated.

I have to put my hand up and say this was my interpretation, I thought the driver added the simulation functionality. I have since read, the Gazebo simulation with the ros control plugin with the function, instead of the driver.

(3) Documentation

Noted regarding the books going out of date (which was from the http://wiki.ros.org/Books list). The tutorials are already out of date and use the previous moveIt API, that are deprecated (or soon to be).

(4) ur_driver vs ur_modern_driver

It seems perverse to keep the ur_driver in the main repository when it is "urged" to use the ur_modern_driver ( https://answers.ros.org/question/2545... ). I can understand the ur_driver still has a use but as with the API ... (more)

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answered 2018-11-14 13:39:38 -0600

gvdhoorn gravatar image

updated 2018-11-15 09:05:22 -0600

Edit:

How do I get a Xenial/Kinetic/UR5/MoveIt/Gazebo simulated system up and running with MoveIt C++ API calls running (with a view to transition to actual hardware)?

My end goal is currently simple, UR5 movement with collision detection of keep out areas.

Can you recommend tutorials or book that explain this, rather than approaching via trial and error?

As an aside: I like how we are apparently at a point where "(runtime) collision detection of keep out areas" with "online real-time motion planning" is currently thought of as "simple" in robotics. Think about it: it's a massive task with all sorts of complicated things going on.

As to your question: I don't know which tutorials you are referring to when you write "they are already out of date", but perhaps first going through the MoveIt tutorials can help give you some overview.

Those should give you a bit more of an idea of the parts that go into the kind of setup that you are trying to create. Not with the UR5, with a different robot, but that is not really a problem: at the MoveIt level those differences don't matter.

re: books: as I don't typically read/use ROS books, I cannot recommend you any I'm afraid.


original answer:

To start: the documentation stating compatibility of the available drivers with the various controllers should be improved. However I believe some of the things you describe / ask about in your question are not just caused by this not being clear.

My first target was to control a simulated UR5 using the MoveIt, Gazebo, RViz and my test application using the Moveit C++ API.

Just to clarify: are you trying to use a driver with a robot in Gazebo? Because that is not needed nor possible.

My current implementation fails when I try to execute move(), a known problem.

Without more information this is not something we can act on. There can be various causes for this, but again, if you're using a simulation no drivers would be needed so I'd first like to get that cleared up.

The ur_modern_driver adds ros_control required for move() support when simulated.

Can you clarify where you read/found this? Because it is certainly not true (or at least not as you phrase it here).

Why has the ur_modern_driver not replaced the ur_driver? Surely everyone will fall at the first hurdle and have to find the above thread?

Because ur_driver still has its uses.

For all intents and purposes ur_modern_driver has replaced ur_driver. See the wiki for ur_driver for instance, Compatibility section:

The ur_driver package has been successfully used with system versions ranging from v1.5.7849 to v1.8.23117. Newer versions seem to have introduced various incompatible changes, and can at present not be used with the ur_driver package.

We recommend users with newer system versions (v3.x and up) to use the ur_modern_driver package.

And the Driver Compatibility notice in the Prerequisites ... (more)

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Also: please keep in mind that books can contain incorrect information and especially instructions can become outdated pretty quickly.

I've not read the book you refer to, but I've seen multiple that are flat-out wrong (but just because they've not been updated for new releases).

gvdhoorn gravatar imagegvdhoorn ( 2018-11-14 13:55:20 -0600 )edit

Thanks for the reply again.

As to quote, it was a compliment to the ROS framework to simplify such a task.

I have been looking at MoveIt tutorials today, I'll continue.

reynot gravatar imagereynot ( 2018-11-15 09:22:07 -0600 )edit

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Asked: 2018-11-14 11:56:17 -0600

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Last updated: Nov 15 '18