The kinematics in the control have very little or nothing to do with the code interpretation. It is only used to tie the machine components together with the control. The kinematics in the post processor (CAM System) have very little or nothing to do with the control nor the kinematics in the control. The only important relationship between the two is they must match or you don't get correct motion on the machine. This is how it compares to marriage. Two distinct (and sovereign entities) must agree on the course of action to have a positive outcome. You must be very careful in the setup and diligent in maintenance. :) Regarding ownership - my wife and I have a 50/50 relationship - what's mine is hers and what's hers is hers too. As long as I respect her opinion in this matter things progress peacefully and positive.
On Wed, Mar 1, 2017 at 7:46 AM, TJoseph Powderly <tjt...@gmail.com> wrote: > i think... > > On 03/01/17 09:16, Charles Steinkuehler wrote: > > On 2/28/2017 5:52 PM, andy pugh wrote: > >> On 26 February 2017 at 22:46, Charles Steinkuehler > >> <char...@steinkuehler.net> wrote: > >>> The A and B Axis has no > >>> dependency on the rotation of the base of the robot arm (joint-0). > >>> > >>> Is this the expected behavior? > >> I don't know. > >> > >> I did notice that the C axis value changes when you rotate the base. > >> > >> Have you seen http://linuxcnc.org/docs/devel/html/motion/5-axis- > kinematics.html > >> ? > > Thanks Andy, somehow I missed that document. I'd gathered most of the > > info from reading through some of the 5-axis kinematics code, but it > > still doesn't really address my problem. I think the closest it comes > > is a couple of places where it mentions "These relationships are > > typically used in the CAM post-processor to convert the tool > > orientation vectors to rotation angles". To me that implies the CAM > > needs to have knowledge about the machine and account for the > > kinematics, but it seems like it's far better to do this on the > > machine side (where all the kinematics and dimensions are known). > > > > Perhaps a different way of asking my question: > > > > Given two types of 5-axis machine, one with A and B pivots on the > > spindle, > for the discussion, some vocab :-) > this is 'knucklehead' like a wrist > > and one with A and B pivots on the table, > this is a 'trunnion' config > > would identical > > gcode be expected to produce identical results on these two machines? > i dont think so, but that can be proven if we get two such machines > together with a single part to execute > really, wether the same gcode or different... it doesnt affect the rest > of this thought > > > > On the machine with the pivot on the spindle, operation seems > > straight-forward: Set the A and B angles, then move around in XYZ to > > machine your part. > > > On the machine that pivots the table, however, after setting A and B, > > if you move around in XY, the Z axis will need to be coordinated with > > the part position (since the part is now tilted, moving in X and Y > > also affects the effective Z position). > > > > So is this difference handled in the kinematics, > (i think) the kins have to handle the difference > 'handle' meaning the relations of the joints for machine motion is in > the kins ( which is a description of the joint relationships ) > > in the 'knucklehead' case, the tool axis ( line thru the cutter center > ) is hypothetical ( aint up/down left right inout xyz ish ) > > in the 'trunnion' case the tool axis is simple cartesian and the > workpiece attitude can be aeroplaney pitch yawed > > will AXIS produce the correct visual given the correct kins? dunno, but > it can be tested, but (i think) AXIS is not a proofing tool > > will a vismach animation follow the correct kins? > hmm i DO think so, given that vismach needs a lot of the relations > that the kins would contain > (also I've modeled a few multi axis systems in vismach ) > > will a CAM system produce the ( or 'a' ) good path given the _same_ > kins, well (i think) its broke if it dont > > and, the trunnion is not always just 'posed', often its dynamic. > > (i think) the CAM has to know the same set of kins and react to corner > cases and two-answer problems the same way > > it only works if both the control and path generator have the same idea > how to get to grandmas house > it only works if both the control and path generator have the same kins > > a control and cam system is usually a marriage, > ( doesnt Siemens own NX now? hehehe ) > > or is it expected to > > be handled by post-processing in CAM? > just my 2c > tomp tjtr33 > > > ------------------------------------------------------------ > ------------------ > 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 > -- Addressee is the intended audience. If you are not the addressee then my consent is not given for you to read this email furthermore it is my wish you would close this without saving or reading, and cease and desist from saving or opening my private correspondence. Thank you for honoring my wish. ------------------------------------------------------------------------------ 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
