On 10/12/2015 08:08 AM, andy pugh wrote: > On 12 October 2015 at 13:59, TJoseph Powderly <[email protected]> wrote: >> Hint: you only need 2 angles, 3 is really overconstrained. >> It ___really___ makes programming easy. >> All programming is just like you had a trunnion table. > > You can do this already in LinuxCNC with kinematics, I think (not that > that is necessarily the right way) > > I think we need to consider whether we want arbitrary arcs or > arbitrary working planes. They are not really the same thing. > > Out of interest, with the Heidenhain code, what happens to the > apparent XYZ when you change plane? Are XYZ still in machine cartesian > space, or does the entire coordinate system shift? > tricky question because it requires some explanation of the Heidenhain way of thinking. These plane tiltings were intended to be a modal change prior to calling very controlled user macros ( filled in by conversational dialogs ) These were crafted to avoid any misallignment of measuring systems. In them, I inspected the current position, insured the current position was stable, then tipped the plane from HERE, so no jerk occured, THEN allowed motion. Motion was relative to the macro's start position (HERE) The user moved in cartesian space PRIOR to tipping the plane and calling my macros. Exit of the macro UN-Tipped the plane.
Since Heidenhain has thousand of work offests arranged in tables (DATUMS), the use simply reference a datum to work at ( identify the Datum table and the index into that file ). That caused the DRO to change ( it was now measuring form the new datum ). Then he moved to 0,0,0,0,0,0,0,0,0 and called the plane function ( tilt ) then the action ( one of many macros for thread at arbitrary angles etc ). Once tilted, the DRO acted like 'normal'. You could select an alternate screen to display it in Machine coordinates or Cartesian. But, once tilted, its easier to think in terms of the new plane. the sequence was finish one detail pick next detail datum move there tilt plane call macro ... rinse repeat hey i just listed 2 of the controls on eBay if you'd liek to play ;) works fine for mills but can do real 5 axis sink edm too. i'd like to see how it could be done in kinematics I hope to get back into this soon, moving now HTH TomP tjtr33 ------------------------------------------------------------------------------ _______________________________________________ Emc-developers mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-developers
