On Monday 03 July 2017 09:52:30 Jeff Epler wrote: > No, it's not currently possible. It would be a welcome topic for > improvement. > > Right now, kinematics is confined to the realtime trajectory planner, > so nothing is known about it at the time soft limits are being > enforced in task. > > A naive approach would be to put a copy of kinematics into task; for > each motion that task considers for soft limits, divide it up "finely" > and make sure each of the points along the motion, it has a kinematics > solution. However, this is probably going to be computationally > intensive, since you're doing the work of kinematics twice. > > I think a plausible way to do this is to allow definition of arbitrary > working volumes using a standard format like .stl. Then, task would > have to answer a much simpler problem: whether any part of the motion > is outside this defined volume. However, it might be wise to use an > existing library to perform this test, rather than writing an > original implementation in LinuxCNC. For example, CGAL's > Side_of_triangle_mesh can tell you whether a particular point is on > the interior or exterior of the volume. > > Of course, while thinking about this it will also be a good time to do > something about the related issue which can be seen on trivkins > machines: some arcs that go outside of soft limits aren't detected by > task. I think this is because only the two endpoints are tested > (which works fine with lines and convex working volumes, but doesn't > work with circular motion or non-convex working volumes): > https://github.com/LinuxCNC/linuxcnc/issues/80 > For arcs which come near the edge (where the AABB of the arc is not > entirely inside the working volume), I suspect a strategy of dividing > up the arc will be neessary to fix this for the complex working volume > case. And remember, "arcs" now includes multi-turn helices which can > additionally be rotated. Oh yeah, and there are NURBs too, even if > nobody uses them. > I am going to try Jeff, if I can figure out how to actually use them. The manpage is sorely lacking in an explanation of how it keeps track of "points" when you feed it a more than 2 sets of points. I have an SS rifle barrel that needs to lose some weight, but I don't envision doing those long sweeping curves using just arcs with 20 yard radii. NURBS looks like it would blend them if I understand it correctly, but I probably don't. :( If, after the next master update, the docs for G5 and G5.x were more explanatory than they are now, I'd be very pleased. Like what does xy, ij and pq actually control when the 2nd, 3rd, 4th etc sets of data are fed to G5 and family. What are the interactions? And how can I make that work on a lathe, where G18 is probably in effect.
If I could understand that, the special config using y connected to the z motor could be hacked up. That way it could run in G17 mode maybe? Confusing, but sortable I believe. > Jeff > > ---------------------------------------------------------------------- >-------- Check out the vibrant tech community on one of the world's > most engaging tech sites, Slashdot.org! http://sdm.link/slashdot > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Genes Web page <http://geneslinuxbox.net:6309/gene> ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
