Hello Austin,
Would you be willing to share your PREEMPT_RT kernel configuration file for
the PR2? I have tried disabling all unnecessary (in my judgment, which
could be wrong!) features for kernel v3.0.25 patched with PREEMPT_RT v44,
but the EtherLab Master node still suffers from a jitter of around 60 us.
Does that sounds reasonable? The high jitter could just be due to our use
of an Intel Atom processor compared to the PR2's Core i7's, but I don't
know how (if at all) that would affect the jitter. What kind of jitter do
you get on the PR2?
Soo-Hyun Yoo
On Wed, Jan 11, 2012 at 11:56 AM, Austin Hendrix <
legotown@aol.com> wrote:
> This sounds nearly identical to the system we use here at Willow Garage on
> the PR2.
>
> We're using a PREEMPT_RT kernel (2.6.31+, moving to 3.0) with a 1kHz
> control loop in user space.
>
> -Austin
>
> Jonathan Hurst <jonathan.hurst@oregonstate.edu> wrote:
>
> >Dear ROS Users,
> >
> >We would like to use Robot Operating System on ATRIAS, the bipedal
> >robot we are building
> >(http://mime.oregonstate.edu/research/drl/Site%20Pages/Atrias.html),
> >but we must have reliable real-time control at 1kHz with communication
> >over an EtherCAT bus. We have assembled some existing software tools
> >to enable this, including the EtherLab driver and Orocos RTT to tie
> >things all together in real time. If you are interested in this
> >discussion, please feel free to join the Email list - it has a brief
> >history with one or two summaries of working systems, but I hope we
> >will have much more detailed discussions, or receive pointers to other
> >working systems. You can sign up for the list here:
> >https://secure.engr.oregonstate.edu/mailman/listinfo/ethercat-ros
> >
> >Jonathan
> >--
>
> >*****************************************************************************
> >Jonathan W. Hurst
> >Assistant Professor
> >School of Mechanical, Industrial, and Manufacturing Engineering
> >Oregon State University
> >204 Rogers Hall
> >Corvallis, OR 97331-6001
> >
> >jonathan.hurst@oregonstate.edu
> >Voice: (541) 737-7010
> >Fax: (541) 737-2600
> >http://mime.oregonstate.edu/research/jhurst/
>
> >******************************************************************************
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