#emc-devel | Logs for 2009-09-24

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[14:48:17] <steves_logging> steves_logging is now known as steve_stallings
[14:50:16] <steve_stallings> It looks like Art Fenerty is at it again with motion planning. He has mentioned a new set of test code that he calls Tempest that is 4th order or more and limits jerk.
[14:51:14] <steve_stallings> He references the University of New Brunswick and I suspect that he is working from the Sonja Macfarlane thesis paper here:
[14:51:23] <steve_stallings> http://www.mech.ubc.ca/~caris/Publications/sonja.pdf
[14:52:20] <steve_stallings> I know the thesis paper is old news, but Art's work is the first real world application that I have heard about.
[14:52:58] <steve_stallings> Discussion is occuring both on the Mach list on Yahoo and on the forum here:
[14:53:02] <steve_stallings> http://www.machsupport.com/forum/index.php/topic,12042.0/prev_next,next.html#new
[15:05:42] <skunkworks_> * skunkworks_ points and gigles at cradek
[15:05:46] <skunkworks_> giggles
[15:06:00] <cradek> what did I do this time?
[15:06:33] <skunkworks_> I think you are the only one that would even attempt this at this time. (and I don't think it is even on your priority list)
[15:06:36] <skunkworks_> :)
[15:06:57] <cradek> nope, not me, I did the last one and look where it got us
[15:07:12] <skunkworks_> it got us a working planner :)
[15:07:29] <cradek> I played with sonja's algorithm a bit and got some proof of concept plots but I never ironed out all the necessary goo.
[15:08:04] <skunkworks_> I don't think it is possible anyways..
[15:08:11] <skunkworks_> * skunkworks_ waits for jepler to impliment it.
[15:08:24] <cradek> dude, you're not supposed to say that
[15:11:40] <skunkworks_> cradek: whats left on jr? other than guards :)
[15:11:59] <cradek> yeah, paint/body work
[15:12:02] <cradek> spindle feedback is half done
[15:12:07] <cradek> probe stuff is not started
[15:12:29] <skunkworks_> how are you shoe horning that in?
[15:12:44] <cradek> it will be easy, I still have lots of room
[15:13:02] <cradek> for the third opto22 board, I made a hinged panel that swings out from the cpu box
[15:13:14] <skunkworks_> cool
[15:14:46] <skunkworks_> are you using the existing resolver for the spindle? or installing something different?
[15:14:53] <cradek> yes existing
[15:15:10] <cradek> it's on the motor - I will have to measure the pulley ratio and hope for the best
[15:15:44] <skunkworks_> chuck an encoder in the spindle and count the 2 for a few thousand rotations.. :)
[15:15:57] <cradek> it has an orient pin so I'll just orient, note encoder counts, turn 100 times and orient, note encoder counts again, then get a high school student to help me with the math
[15:16:10] <skunkworks_> heh
[15:16:27] <cradek> your idea is better, if I had one I would do that
[15:18:34] <skunkworks_> what we need is a university excited about emc - then someone could impliment the new planner for a thesis..
[15:18:39] <skunkworks_> Thesis?
[15:19:02] <cradek> hm I just realized that probe compensation is easy - have a var value per axis that you add to the probe result
[15:19:09] <cradek> I think that's all it takes
[15:19:23] <cradek> you just calibrate by measuring how far the ball is from the centerline
[15:19:54] <cradek> which is just bore a hole and probe it I think
[15:23:06] <skunkworks_> the probe move would always have to be parallel with the axis?
[15:38:21] <cradek> skunkworks_: good question
[15:47:07] <steve_stallings> steve_stallings is now known as steves_logging
[17:10:03] <alex_joni> skunkworks_: that seldom works
[17:50:22] <cradek> skunkworks_: I think it doesn't matter which direction you move.
[17:53:07] <cradek> hm, but it's probably disconcerting if you are at Y0 and probe the left edge of something (probe X positive motion) and get a touch point of X1.234 Y.00123
[17:53:39] <cradek> if you probe a hole center, you definitely want that Y offset to be reported
[17:54:08] <cradek> yeah I'm back to thinking it's easy - if probing the left edge you only care about the X value anyway.
[20:34:32] <CIA-7> EMC: 03micges 07master * rc5a363d042cf 10/src/emc/ (5 files in 3 dirs): Remove one more obsolete AXIS_STAT varable
[23:23:15] <jmkasunich_> jmkasunich_ is now known as jmkasunich