Hi Ben, Thanks for the ideas, option 3 makes the most sense to me and I guess the best approach is to rig up a couple of servo motors and start experimenting.
Dave On Aug 24, 2007, at 3:38 AM, ben lipkowitz wrote: > Dave Engvall wrote: > >> Think long arm sewing machine for quilting. The rotational axes >> are the >> needle and the bobbin. The tracking give constant stitch length. > >> Two are X and Y and the other pair need to track (rotationally) >> with in >> a few degrees or better. Rotational speeds are from zero to 1800 >> rpm for >> one axis and either 1:1 or 2:1 for the other. The speed of >> rotation and >> the vectorized X and Y velocity need to track each other. > > you could do it a few different ways > > option 1) write a kinematics module and treat the needle/bobbin as > rotational axes within emc > > option 2) use the hypot component to calculate distance traveled by > x and > y and feed that to your needle axis as a position command > > option 3) differentiate the output from above with ddt and feed it > to the > needle "spindle" as a velocity command. might be slightly less > accurate > than 2 but you won't need to do silly hacks to prevent counter > overflow. > > option 4) synchronized motion like for lathe threading. this would be > better if your needle is not very responsive compared to X and Y, but > harder to write g-code for. (?) for example you couldn't do any arcs. > however you could easily turn the spindle off and move around without > stitching anything. options 2&3 would require using an M-code to > disconnect the spindle from x-y motion. also the K parameter to G33 > allows > you to easily change the stitch length right in your g-code. > >> There are two modes of motion. (1) is driven by an operator moving >> the >> carriage(s) in X and Y and (2) X and Y will be under G-code control. > > this should work fine using teleop mode under option 1 or just regular > jogging under 2&3&4. > > > > ---------------------------------------------------------------------- > --- > This SF.net email is sponsored by: Splunk Inc. > Still grepping through log files to find problems? Stop. > Now Search log events and configuration files using AJAX and a > browser. > Download your FREE copy of Splunk now >> http://get.splunk.com/ > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users ------------------------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
