Multimaster - Groovy

[Daniel Stonier]

Hi all,

Coming up to groovy. Time really flies fast - it's already two versions of ros gone past and we haven't really moved anywhere except for a couple of new implementations that service particular use cases. I had hoped we'd be a bit farther down the road, but I understand everyone is busy. Myself included, I got derailed twice in the last year just as I was about to launch into some serious work.

I'd like to really get into the groove with groovy (bad joke :P). 

With the funding we have for our new project, I'm ready to go and have been going over what we've done before, what others have done and started hacking on github. I also have a new colleague at work who should be able to help, and a couple of groups have contacted me with an interest in collaborating, even if only on the testing/feedback level. So I'm ready to go and we need to get a bit more organised than we have been. 

The first area, which seems to be fairly common across use cases is to properly build ros api (topic,service,action) synchronisation and discovery between ros systems - aka the previously discussed Gateways. If that is built well, a variety of multi-robot solutions can then easily be built on top. Keeping that variety at a higher level is probably fairly important at this stage - no one solution appears to satisfy every requirement.

To avoid some of the meandering we've had in the past, I think it would be a good idea to concisely list the design goals we'd like to see for a gateway proposal. Ideally, this should be in the spirit of an REP and possibly something we should promote as an REP at some stage. If we can incorporate everyone's needs in these design goals, hopefully we can generalise the building blocks in such a way that everyone (or most everyone) can make use of them directly rather than having to maintain their own.

I updated the groovy planning page, please contribute to this information if you wish:

• http://ros.org/wiki/groovy/Planning/Multimaster
• http://ros.org/wiki/groovy/Planning/Multimaster/REP%20Proposal
• http://ros.org/wiki/groovy/Planning/Multimaster/Existing%20Techniques

Thoughts?

Regards,

Daniel.

PS Piyush, where are you at with your development?

[Piyush]

Hi Daniel,

Thanks for setting up the REP proposal!

We have been busy moving our project along, and now have the robots
and machines ready. Since master_sync did not survive the transition
to Fuerte (changes to master api), I have temporarily moved our system
to a single master. We are also right now not running all the robots
simultaneously, but that should change soon. We were planning on
moving outside of our lab environment (aka bad network connections) in
a month's time, and that was when I was planning to come back to this
discussion again. Since our ultimate goal is a scalable building wide
system, this discussion is still extremely relevant to us.

I've looked through the design goals, and I agree with all of them.
I've added a few comments at the bottom of the page -- dealing with
synchronizing the ROS clock and the TF tree.

If you're looking for more people to aid with development, I will be
happy to help with whatever spare time I have. Let me know
accordingly.

Thanks!
Piyush