On 8 November 2010 06:14, Stuart Glaser wrote: > Hi Daniel, > > The RealtimePublisher will work fine on a non-realtime system.  It may > be slightly less efficient than normal ROS publishing, but I don't > think you'll notice any difference. > > -Stu Ok, just browsed through the code - should have done that earlier instead of making assumptions. Looks like it is just providing mutex locking protections. Thanks for the heads up. Regards, Daniel. > On Sun, Nov 7, 2010 at 6:03 AM, Daniel Stonier wrote: >> Hi all, >> >> I've been working over the last few weeks to put together a core robot >> subsystem for one of our robots - it's pr2 like with a mobile base, a >> manipulator and various other motor driven mounts (14 motors in all), >> but on an a real budget and I was wondering what experiences others >> have had doing something similar. >> >> The primary challenges with ours are two fold: >> >> 1) It isn't running an ethercat based system. i.e. it's non-real time, >> though thats something I would like to upgrade on this particular >> robot in the future, however its not something that all of our robots >> will have. This means the motors are often driven on multiple loops, >> some fast and some slow (so not to burden the low spec embedded >> board). Also, the controllers in ros are using a real time publisher - >> and I made the assumption that is not usable for non real time (please >> correct me if I'm wrong!), so rebuilt all the >> controllers/transmissions we had to use. >> >> 2) We're running on a low spec intel atom (the lowest), so topic >> communication and loop frequencies need to be kept down. Since its not >> centralised, it needed some care designing to ensure callback >> frequencies didn't escalate and control loop periods weren't consuming >> too much horsepower. Most of it is interrupt driven now too because >> different subsystems are cycling at different speeds. >> >> Finally, its roughly working, but its quite ad-hoc and took alot of >> building in the long run and am wondering if there's an easier way to >> do it, or a way to genericise components so that they can be recycled >> for both non-realtime and realtime systems. >> >> Regards, >> Daniel Stonier >> >> -- >> Phone : +82-10-5400-3296 (010-5400-3296) >> Home: http://snorriheim.dnsdojo.com/ >> Yujin Robot: http://www.yujinrobot.com/ >> Embedded Ros : http://www.ros.org/wiki/eros >> Embedded Control Libraries: http://snorriheim.dnsdojo.com/redmine/wiki/ecl >> _______________________________________________ >> ros-users mailing list >> ros-users@code.ros.org >> https://code.ros.org/mailman/listinfo/ros-users >> > > > > -- > Stuart Glaser > sglaser -at- willowgarage -dot- com > www.willowgarage.com > _______________________________________________ > ros-users mailing list > ros-users@code.ros.org > https://code.ros.org/mailman/listinfo/ros-users > -- Phone : +82-10-5400-3296 (010-5400-3296) Home: http://snorriheim.dnsdojo.com/ Yujin Robot: http://www.yujinrobot.com/ Embedded Ros : http://www.ros.org/wiki/eros Embedded Control Libraries: http://snorriheim.dnsdojo.com/redmine/wiki/ecl