<enleth> so I had this idea a couple years ago to mount the toolhead on a non-contact plotter-like gantry machine (such as a plasma cutter) on a small, limited range X-Y stage, in addition to the regular X (gantry) and Y (linear stage on the gantry) axes
<enleth> or perhaps just an additional linear stage parallel to X
<enleth> the idea here being to split the toolpath in frequency domain and use the small stage for the high frequency part
<enleth> never tried it, mostly for the lack of software support in pretty much any machine control out there
<enleth> and now I'm wondering how much work would it take to get LinuxCNC to understand and use such a configuration
<enleth> obviously the whole point is being able to run detailed toolpaths fast on a machine that would otherwise lack the rigidity and/or power to do that
<enleth> any thoughts?
<_unreal_> What are you asking
<Jymmm> CaptHindsight: It is I, no promises on the latter  ;)
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<enleth> _unreal_: high-level comments, especially from people familliar with LinuxCNC's motion planner and HAL. I assumed this is obvious when asking for "any thoughts" after describing a high-level idea dependent on the internals of the motion planner and HAL.
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<_unreal_> enleth, AGAIN.... WHAT are you asking I've read it multi times now...... your question is not really narrow
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<_unreal_> I assume you mean you want to setup a TOOL rotation system so you can swap tools. THAT IS NOT an XY setup. but an A  rotation style axis generally. unless you want to use some kind of a PICK and PLACE system to pick up a TOOL from a XY matrix style tool holder....
<_unreal_> SOOO... narrow the scope of WHAT your are asking
<enleth> _unreal_: jesus, not everything said here has to *be* a narrow question. if you really insist, the question is: "what do you guys think, is that even remotely doable within the LinuxCNC codebase as it is now, or am I hosed"?
<enleth> _unreal_: no, you completely misunderstood it
<_unreal_> I may have no argument
<_unreal_> brb OMG 9:40 putting my 9yo to bed
<_unreal_> one sec
<_unreal_> I'm back
<_unreal_> kids to bed
<enleth> _unreal_: this is about doing fast moves on a heavy or wobbly machine, by being able to move the tool itself relative to the toolhead, separately from the machine's "regular" axes, with a very limited range of motion but at a potentially much higher speed than the "regular" axes can do
<_unreal_> What kind of a mchine
<_unreal_> machine
<enleth> gantry plotter comes to mind, but this really isn't that important
<_unreal_> stationary or moving gantry
<enleth> that's utterly, completely irrelevant
<enleth> I'm not asking about a particular machine
<_unreal_> it is important because every moving part ADD'S the error range of play
<enleth> I'm getting the impression that we're not quite on the same page here
<_unreal_> fine ok.. hypothetical a plotter with a DUAL X plane
<veek> anyone familiar with the Aluminium Classification system?
<_unreal_> I'm having a hard time picturing an XY/XY table
<enleth> what I'm asking about is a motion control idea/model/concept, how the machine looks makes absolutely zero difference
<_unreal_> sorry XY/XY flimsy fast plotter
>veek< AM i WORNG?
<_unreal_> veek, are you asking about its grade of duriblity and MOMENT?
<_unreal_> sorry flex and moment
<veek> nope the whole 1xxx implies 99%
<veek> what does the 2nd digit etc imply
<_unreal_> duriblity lol I've had to much wine and I'm on  my first cup :)
<_unreal_> OHOHHHHHHHHH.... ya that I cant answer
<enleth> _unreal_: it's probably better if you imagine a VERY heavy machine that would need to slow down a lot to trace a complex toolpath with very small details, like a high amplitude sine wave set diagonally to the axes
<_unreal_> I'd have to google
<_unreal_> enleth, ok... microstepping.... on a machine with high backlash
<enleth> _unreal_: with a dual X/Y stage, one of them very small and right at the toolhead, the machine as a whole could zoom over the toolpath in a straight line, with only the tool itself doing the sine wave
<enleth> jesus, no
<veek> _unreal_, https://www.esabna.com/us/en/education/blog/understanding-the-aluminum-alloy-designation-system.cfm
<enleth> what microstepping
<enleth> what backlash
<enleth> completely missing the point
<_unreal_> veek MSG
<veek> good explanation my book sucks
<_unreal_> veek,  check msg
<enleth> _unreal_: I'm sorry, I tried, but I don't think I'm getting anything across now. and my whole question is a long way up in the backlog and no one else is going to read it and comment on it
<enleth> what a waste of time
<_unreal_> I'm trying. I'm a marine engineer
<_unreal_> but the question that I'm reading I've answered as best I can..... as I said its best to narrow your question and build up.......
<_unreal_> your asking a question that is NOT making sense.
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<enleth> the question was about the LinuxCNC software internals and control theory, NOTHING to do with the mechanical implementation
<_unreal_> linuxcnc is very flexable and can be scripted.......
<enleth> not at that level, I think
<enleth> and I know it is, I'm using it
<_unreal_> if you feel that the lincnc is not capable then you need to take it to a hardware level abstraction layer and use a micro controller to preform automated functions
<enleth> what
<enleth> again, what you said has nothing to do with anything
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<_unreal_> http://linuxcnc.org/docs/html/man/man1/iocontrol.1.html
<enleth> yes, I know where the manual is, this is irrelevant
<_unreal_> At this point I'm sorry I give up... I dont know what your desired answer is between what your writing and thinking sorry.
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<enleth> _unreal_: you're a marine engineer, right? so try to imagine someone asked you to draw a sine wave - 2m in amplitude, 4m period - with a stick on water, while you're standing at the stern of a 80000 DWT tanker. you're holding the stick in your hands, it's long enough to reach the water. would you rather try to get the whole tanker to strafe left and right by 2m as it's moving forward, or just let the
<enleth> ship move in a straight line and wave the comparatively lightweight stick with your hands so that the end in the water traces a sine wave?
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<enleth> the end result would be exactly the same if you held the stick straight and somehow got the ship to move sideways at a 2m amplitude, 2m period, but surely you can see a problem in trying to do that with a tanker
<enleth> even if you tried using side thrusters, the mass of the ship would just completely dampen that sideways movement, or you'd have to move the whole thing *extremely* slowly
<enleth> eh, now no one is going to comment anything on what I originally wrote because no one's going to read it anymore
<enleth> _unreal_: and, yes, I am aware that a line traced in the water with a stick while standing on a big ship's stern is going to disappear right into the ship's wake, let's just assume it doesn't