Using kuka_rsi_hw_interface: where to start?

Question

Using kuka_rsi_hw_interface: where to start?

dav1d-wright opened this issue 4 years ago · comments

Hello and sorry in advance for this noob question!

I have a KUKA KRC4 Compact controller and a KR 10 R900 sixx manipulator for which I would like to implement a path-correction application. As far as I understand it's possible to compute the path correction on a separate computer which is connected to the KRC4 Compact via RSI which uses the EtherCat interface (is that correct?). Now my problem is that I can't really find any documentation on how to do this. Could someone please point me to any helpful resources?

I would be entirely grateful for any hints on how to use the kuka_rsi_hw_interface with a KRC4 Compact

Best,
David

Lars Tingelstad · Answer 1 · Wed Nov 04 2020 22:13:07 GMT+0800 (China Standard Time)

Hi David!

the kuka_rsi_hw_interface works with and was developed on the KRC4 Compact. You can find the installation procedure here.

G.A. vd. Hoorn · Answer 2 · Wed Nov 04 2020 22:24:16 GMT+0800 (China Standard Time)

I would like to implement a path-correction application

While technically this would be possible with kuka_rsi_hw_interface, the assumption in that component is mostly that you'll be using RSI to "take over" control of a KUKA robot from a ROS PC. Overlaying corrections would be similar, but different from what the component currently does.

which uses the EtherCat interface

Not completely. RSI is used over a regular ethernet connection, which carries UDP datagrams.

It will be important to understand whether you're looking to implement ROS control over a KUKA, or whether you're going to be using RSI to overlay corrections. The former can be done after following the documentation linked to by @tingelst. The latter will require more work (and will require you to implement some parts yourself).

G.A. vd. Hoorn · Answer 3 · Wed Nov 04 2020 22:26:41 GMT+0800 (China Standard Time)

As this appears to be a usage/configuration question, and not so much a report about a problem with the packages in this repository, I'm going to close the issue.

If it turns out there is something to fix, we can re-open.

Feel free to keep commenting on it of course.

David Wright · Answer 4 · Wed Nov 04 2020 22:36:07 GMT+0800 (China Standard Time)

Hi to both of you, and thank you very much for your quick and helpful responses!

Ultimately my task is to implement a vision-based path correction. However, as it is yet in a very early stage I believe I could use the existing functionality to implement a simple movement and then overlay the correction, or also extend the functionality as you suggested.

First of all I will look into the readme that @tingelst provided (thank you again). In the meantime, @gavanderhoorn, could you point me to where I would start digging in order to add a path-correction approach?

G.A. vd. Hoorn · Answer 5 · Wed Nov 11 2020 18:30:41 GMT+0800 (China Standard Time)

If you're just starting out, I would not use kuka_rsi_hw_interface as a template or starting point.

There are some assumptions in that hardware interface which you are immediately violating by not using RSI to completely control a KUKA.

While technically RSI always overlays offsets on motions, none of the ros_control controllers will be able to deal with this if you start using it as such. You could write a ros_control controller which can do this though. You might not even have to change anything in the hardware interface itself.