On Sep 16 2013 1:44 PM, Florian Rist wrote: > Hi > >> I think a larger read-ahead is the priority. > > Another option, at least for me, would be to have a g-code > pre-processor > that filters the tool path and creates a one that the machine will be > able to follow quickly, either in an unsafe operation mode or whit > the > existing look-ahead functionality. > > I think doing at least a bi-arc filtering prior to execution would > speed > up things in many situations, especially in free form milling. > > If the pre-processor would do b-spline fitting and incorporate not > only > some max. deviation settings, but also specific characteristics of > the > machine, things could become really smooth.
Fitting b-spines, etc would have to be a per-processing step. All the fitting code I have ever done to so much time that it would completely blow any RT constraints. Also, it completely replaces the geometric representation. When I played at this before (albeit over a decade ago) I would look ahead how ever many moves it took to spin up the machine to it max rated speed limited by all actuators participating in the move. The point in time where the tool reached the maximum velocity was marked with temp pointers, as well as the positions/times where the programmed motion would be synchronized. At each joint, any change in acceleration required for blending is calculated as a hard requirement. From there you know how the machine should behave given the limits of the machine, and the target. You also know that if you adjust the speed/feed override that you have the upper limit of what the joints can do, and the rest is scaling the points down from there. As another poster had said, as you are moving along, you only have to look ahead until the end of the next move is greater than the time to stop all movement given the maximum acceleration and speed (this should be the longest). If the blender can achieve this in real-time then it should be able to deal with slower moves (taking more time). For generality, I would feel better to make that stop length * 10. I doubt that would require to big a memory buffer. EBo -- ------------------------------------------------------------------------------ LIMITED TIME SALE - Full Year of Microsoft Training For Just $49.99! 1,500+ hours of tutorials including VisualStudio 2012, Windows 8, SharePoint 2013, SQL 2012, MVC 4, more. BEST VALUE: New Multi-Library Power Pack includes Mobile, Cloud, Java, and UX Design. Lowest price ever! Ends 9/20/13. http://pubads.g.doubleclick.net/gampad/clk?id=58041151&iu=/4140/ostg.clktrk _______________________________________________ Emc-developers mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-developers
