On July 24, 2010 11:50:02 am EBo wrote: > In the spirit of helping out... > > > I see that FreeRTOS has been ported to the x86 platform, and might be a > > better fit in some ways than linux. Also, if the motion controller were > > moved to a separate micro controller, there would be no need for a > > real-time OS (a CPU that only runs one program doesn't need an OS-- > > and might be better off without one). > > I've programmed FreeRTOS a bit. One of the things you need to be aware of > is that the standard timing loop is only 1us. To get reasonable fast motor > speeds you will have to use the fast interrupt driver and roll your own > handler. On the other hand, that is not to difficult. I posted some > template code for this to the Make Microcontroler forum. Other than that, > there are a number of unix specific stuff that will probably require a LOT > work to replace the underlying functionality. If you go this route I wish > you the best. > > > [And yes, I'm aware that the RepRap controller software has been adapted > > to other projects. I plan to play with that for a while before deciding > > whether to dive into EMC2.] > > I might be wrong about this, but here are some thoughts about EMC2 and > RepRap. > > As far as I know the real-time kinematics in RepRap are fairly simple. > The implication there is that it will work fine for slow actuators but I am > not sure I would trust it for a stage moving at 1000+ IPM. The faster > something is moving, and heavier it is, the more damage that can happen > when something goes wrong. Before using the RepRap code on my Van Norman > retrofit with high speed servos, I would really want to know the limits of > their software. Maybe it is up to snuff... I just do not know. > > In EMC, NIST got the physics right -- so you can trust it to control some > way-out-there stuff. On the other hand, it is big, bulky by comparison, > and can be a bit of a pain to install/configure. > > As a note, I've been thinking about taking a stab at extending RepRap > using the real-time version of the Plan 9 distributed operating/file > system. A version of the Plan 9 file system was ported to the LEGO > Mindstorm controller (called styx-on-a-brick) in roughly a 12k executable. > The cool thing about this approach is that each of the axis can be > distributed and controlled via any machine which can communicate via the 9p > files system protocol. If this interest you give me a poke in 3 or 4 > months and I will see if I have time to pick this project up (I'm finishing > my thesis research at the moment, and working on a Plan 9 related project > which was accepted for this years Google Summer of Code, so I am insanely > busy). > > Hope this helps, > > EBo -- > >
EMC is one of the "official" software systems to control RepRaps: http://reprap.org/wiki/EMCRepRap http://forums.reprap.org/list.php?155 Right now the extended community is unaware of this, and the devs are having soooo much fun that the documentation is a little patchy. E pur si muove!* http://bothacker.com/ EBo, I'd suggest joining the reprap-dev mailing list: http://lists.reprap.org/mailman/listinfo/reprap-dev and lay out your idea. ------------------------ RepRap doesn't really do "official" any more; right now there is a lot of energy around this: http://reprap.org/wiki/Arduino_Mega_Pololu_Shield But I'm more interested in what is hiding in bothacker's project box. Old pentium whitebox pcs may not be as sexy as arduino megas, but they, and pc104 boards may be better. ... There are many many different ways to build a RepRap, all of them official. -Sebastien RepRap.org * http://en.wikipedia.org/wiki/E_pur_si_muove! ------------------------------------------------------------------------------ This SF.net email is sponsored by Sprint What will you do first with EVO, the first 4G phone? Visit sprint.com/first -- http://p.sf.net/sfu/sprint-com-first _______________________________________________ Emc-developers mailing list Emc-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-developers
