On 3/1/2017 12:09 PM, Andrew wrote: > 2017-02-25 23:46 GMT+02:00 Charles Steinkuehler: > >> Is anyone else doing 5-axis machining with genserkins? >> > > Not exactly machining... but I'm building a 3D printed stepper driven > 6-axis robot arm. So I hope that I'm going to need genserkins soon. > > The AB behavior you describe (if I get it correct) might make some sense. > When you rotate the whole arm and AB angles remain the same in the world > coordinates (that's what you want), the wrist tends to twist impossibly. So > probably this behavior is designed on purpose.
Hmm...I see your point, but commanding an AB orientation in world space via gcode would then require knowing the position of the first joint (the base rotation of the whole arm), which is generated from the commanded position via kinematics. In the simple Puma-like serial arm I'm working with this might be possible, but in other arrangements (where more than one axis is rotating around world Z) there are multiple valid solutions, so you can't really infer exact joint positions from the gcode. This really feels like something that either needs to be handled in the machine kinematics, or the gcode needs to be directly controlling the joints (pushing the kinematics off to the CAM system) unless I'm missing something. > I think genserkins can be tweaked to use world AB coordinates. Any pointers for how to do this? I haven't gotten very far through the "gomath" library yet, which is where most of the fun stuff seems to be happening... -- Charles Steinkuehler char...@steinkuehler.net ------------------------------------------------------------------------------ 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
