#linuxcnc-devel Logs

Apr 08 2018

#linuxcnc-devel Calendar

05:28 PM sliptonic: Anyone here familiar with scarakins?
05:30 PM seb_kuzminsky: i've opened the sample config once or twice, does that count?
05:30 PM sliptonic: Maybe enough to give advice :-)
05:30 PM sliptonic: Here's my issue:
05:30 PM seb_kuzminsky: hmm
05:30 PM Tom_L: he's lazy, it's the weekend
05:31 PM seb_kuzminsky: that's understandable
05:31 PM sliptonic: I've got a scarabot ibm7575. The motor that controls the end effector rotation around Z axis is in the pedestal and connected with a clever set of belts. The result is that the rotation is automatically cancelled out of the movements of the first two joints.
05:31 PM jthornton: that might be a network error
05:32 PM sliptonic: So I need a version of scarakins that does NOT correct C rotation.
05:32 PM jthornton: I've gotten something like that before and just tried again Tom_L
05:32 PM seb_kuzminsky: sliptonic: ok
05:32 PM Tom_L: i tried a few times
05:32 PM sliptonic: But I don't understand the code well enough to patch it.
05:33 PM -!- #linuxcnc-devel mode set to +v by ChanServ
05:33 PM seb_kuzminsky: Tom_L: i still think it's a network problem between you and linuxcnc.org
05:33 PM seb_kuzminsky: can you try it from a different place on the internet?
05:35 PM Tom_L: what do you mean?
05:35 PM Tom_L: oh different debian host?
05:36 PM Tom_L: yeah but i'll have to start over on it
05:36 PM seb_kuzminsky: Tom_L: everything I read suggests there's a (possibly transparent) proxy between you and linuxcnc.org that's responsible for that problem.
05:36 PM Tom_L: how do i find it?
05:36 PM seb_kuzminsky: linuxcnc.org doesn't *have* an InRelease
05:36 PM seb_kuzminsky: so it can't be responsible for serving you a bogus one
05:37 PM seb_kuzminsky: first, try accessing linuxcnc.org from a different place on the internet, for example by connecting through a coffee-shop wifi or through your cell phone, to see if that fixes it
05:38 PM Tom_L: they might frown on me taking a desktop pc into starbucks :=)
05:38 PM seb_kuzminsky: if that fixes it, you have the un-enviable task of convincing your ISP they should remove or fix their transparent web proxy, and i wish you a sarcastic "good luck with that"
05:39 PM seb_kuzminsky: sliptonic: scarakins.c has two functions that implement the kinematics: kinematicsForward() and kinematicsInverse()
05:40 PM seb_kuzminsky: there's also an rtapi_app_main() function that exports and initializes the hal pins
05:42 PM seb_kuzminsky: i think your task is to add a load-time parameter to enable this new feature you want to add, probably using RTAPI_MP_INT
05:43 PM seb_kuzminsky: then update kinematicsForward() and Inverse() to inspect that flag and enable or disable the new pedestal behavior you want
05:43 PM seb_kuzminsky: i don't know enough about scara kinematics to offer you suggestions on how to do that
05:44 PM seb_kuzminsky: bit i note that scarakins is pretty small and looks straight forward
05:46 PM sliptonic: Hmm. Ok Will give it a shot. Can you point to any sample code for a load-time parameter/RTAPI_MP_INT?
05:46 PM seb_kuzminsky: we have this documentation: http://linuxcnc.org/docs/devel/html/man/man3/RTAPI_MP_INT.3rtapi.html
05:47 PM seb_kuzminsky: "git grep RTAPI_MP" in src/ finds many examples of where different module parameters are used
05:48 PM seb_kuzminsky: for example here: https://github.com/LinuxCNC/linuxcnc/blob/master/src/emc/motion/motion.c#L40
05:49 PM sliptonic: ok. It's well out of my comfort zone but..nothing ventured, nothing gained! Thanks.
05:51 PM seb_kuzminsky: sliptonic: welcome, it's not much but it's all i got, i'm really not familiar with the scarakins math at all
05:51 PM seb_kuzminsky: you're involved in freecad, aren't you?
05:52 PM sliptonic: I am.
05:52 PM seb_kuzminsky: i saw you guys release 0.17, congrats, and thank you!!!
05:52 PM seb_kuzminsky: that's super awesome
05:52 PM sliptonic: Thanks. It was a long time coming. 17 still has some issues but the new CAM workbench (Path) is really nice
05:53 PM seb_kuzminsky: i'm so excited about that
05:53 PM seb_kuzminsky: i've been watching the folks in debian-science working on packaging it for debian
05:53 PM sliptonic: That's the stuff I've been helping with. Dan Falck and I got it started with Yorik a few years ago but most of the user facing stuff just got done in the last 18 months
05:54 PM seb_kuzminsky: you prototyped with libarea, then moved away frmo that, is that right?
05:55 PM sliptonic: Yes. libarea uses the clipper lib. One of our guys wrote a replacement wrapper that uses clipper but does it better
05:56 PM sliptonic: Functionally the same offsetting though
05:56 PM seb_kuzminsky: neat
05:56 PM seb_kuzminsky: i looked at clipper but came away with the impression that it doesn't understand arcs, and uses linear splines to approximate them instead
05:57 PM sliptonic: There's a very basic support for OpenCamLib too but only one basic operation has been written. Much MUCH more is possible now and all in python
05:57 PM sliptonic: Unfortunately it will require a manual/separate install of OCL
05:58 PM seb_kuzminsky: i can't wait to try 0.17
06:00 PM sliptonic: I think once FreeCAD gets assemblies, it will start putting the scare to some commercial packages.
06:00 PM seb_kuzminsky: :-)
06:01 PM seb_kuzminsky: i don't care that much about competing with the commercial guys, i just want this power natively in the open source world for everyone to use and build on
06:02 PM seb_kuzminsky: cam's been the missing key for me, for a lot of projects, this promises to fix that
06:02 PM seb_kuzminsky: so thank you for your work on that!!!
06:04 PM sliptonic: Your welcome. Let me know what you think. If you see features (especially anything in the linuxcnc post) that are missing let me know. That's really become the reference post processor that all the others are based on.
06:05 PM seb_kuzminsky: i will let you know for sure
06:52 PM Tom_L: the isp says they don't use proxy servers
06:55 PM Tom_L: i'll try it again here in a bit
08:11 PM Tom_L: ok i tried a different mirror and it worked this time
08:11 PM Tom_L: go figure
09:51 PM seb_kuzminsky: Tom_L: a different mirror of what? as far as i know, there are no mirrors for linuxcnc.org
10:14 PM Tom_L: used a different debian site
10:14 PM Tom_L: ftp from texas
10:34 PM seb_kuzminsky: ok, that's probably unrelated to the linuxcnc.org InRelease error
10:34 PM seb_kuzminsky: i'd guess someone broke a cache or a proxy between you and linuxcnc.org, and then fixed it
10:34 PM seb_kuzminsky: anyhoo, glad it's working for you now