Ask Your Question
0

Can ROS control a robotic arms TCP along a linear trajectory, holding a constant TCP speed?

asked 2018-05-31 06:49:23 -0500

bumbastic gravatar image

Like most industrial robot controller has the ability to move linear from A to B, e.g. Fanuc command(L P[1] 800mm/sec CNT90 ) command. Can ROS control a robotic arms TCP along a linear trajectory, holding a constant TCP speed?

edit retag flag offensive close merge delete

1 Answer

Sort by ยป oldest newest most voted
1

answered 2018-05-31 06:53:27 -0500

gvdhoorn gravatar image

updated 2018-06-01 10:01:13 -0500

You give us very little information / context. In addition, the question "can ROS do X" is too vague: there are many pkgs in ROS and not all of them provide the same (level of) functionality or support the same features.

As a comment on your question: yes, provided that:

  • you use a driver component that either supports this directly, or,
  • provides sufficient control bandwidth to implement this from joint space, and
  • use a trajectory generating component that generates Cartesian trajectories

Edit:

I want to build and use a robotics arm with 6-7dof and a tool attacth to it on the last link. It can be e.g. a grinding, painting or welding tool, able to process the surface of a workpiece by controling the movement of the tool between viapoints. Any sugestens that can get me on the right path?

This seems like a true xy-problem.

Yes, this is possible. Not trivial though. See this video fi. The software that was used can be found at ros-industrial-consortium/godel.

But realise that this does much more than simply executing a bunch of linear motions (there are actually very few linear motions in that video): it automatically scans a scene, detects surfaces, plans process paths and executes them with obstacle avoidance.

holding a constant TCP speed?

As to this specific requirement: that is harder, and will probably require creating a Cartesian controller or finding one.

Not much work is done like this as motion planners typically used in ROS typically plan in joint space.

If you are looking for something similar to the FANUC TP language, then that doesn't exist afaik. There have been some efforst in the past, but I don't think they lead to something in the end. See #q283428 for some more discussion.


Edit2:

Thank you for the links to godel. My daily work is much like in this project. but we mostly paint parts that we 3d-scan, segment, pathplan, motionplan, and generate robot programs. I look at ROS now, and want to learn, because I expect it one day will be capable as a replacement of our old platforms

Continuous robotic processes are typically much alike. Blending is removal, painting is additive, but the basic principles are the same.

The same software is also being used for paint removal and painting itself.

edit flag offensive delete link more

Comments

I want to build and use a robotics arm with 6-7dof and a tool attacth to it on the last link. It can be e.g. a grinding, painting or welding tool, able to process the surface of a workpiece by controling the movement of the tool between viapoints. Any sugestens that can get me on the right path?

bumbastic gravatar imagebumbastic ( 2018-05-31 07:28:54 -0500 )edit

Thank you for the links to godel. My daily work is much like in this project. but we mostly paint parts that we 3d-scan, segment, pathplan, motionplan, and generate robot programs. I look at ROS now, and want to learn, because I expect it one day will be capable as a replacement of our old platforms

bumbastic gravatar imagebumbastic ( 2018-06-01 07:13:43 -0500 )edit

Again thank you for showing me godel. I want to look in to that project.

bumbastic gravatar imagebumbastic ( 2018-06-01 07:17:26 -0500 )edit

I just fell over the pkgs. descartes do you know if it is still the plan to integrate it into MoveIt?

bumbastic gravatar imagebumbastic ( 2018-06-01 07:29:10 -0500 )edit

descartes is used / was used in godel.

re: moveit & descartes: see the recap of the latest MoveIt maintainer meeting.

gvdhoorn gravatar imagegvdhoorn ( 2018-06-01 07:34:15 -0500 )edit

Thank you. The recap has focus on cartesian trajectorie messages to MoveIt. Now I am even more motivated to get started with ROS. What I need is coming soon :)

bumbastic gravatar imagebumbastic ( 2018-06-01 08:20:02 -0500 )edit

Generating Cartesian trajectories is already possible, there are just some extensions to MoveIt that could make this easier. You don't need to wait necessarily.

gvdhoorn gravatar imagegvdhoorn ( 2018-06-01 10:03:14 -0500 )edit

Yes, i can see that. And i wont wait. But it will take me time to get to know ROS, i can only work with ROS in my free time. now i know somebody is working on making it easy to motionplan combined joint and cartesian trajectories. That tells me that I could bring ROS to my real job when I am ready.

bumbastic gravatar imagebumbastic ( 2018-06-01 14:02:57 -0500 )edit

Your Answer

Please start posting anonymously - your entry will be published after you log in or create a new account.

Add Answer

Question Tools

Stats

Asked: 2018-05-31 06:49:23 -0500

Seen: 217 times

Last updated: Jun 01 '18