Re: [Emc-users] synchronized axes.
>>> 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. > > 3A) differentiate the X and Y positions _before_ the hypot, then send > the X and Y velocities to the hypot. The hypot is the vector velocity, > which is the required spindle velocity (scaled as needed). > > Other than that, I agree that 3 is the way to go. I just noticed that there's a HAL parameter that does this already: motion.current-vel maybe it should be a pin instead - 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
Re: [Emc-users] synchronized axes.
Dave Engvall wrote: > 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. > >> 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. 3A) differentiate the X and Y positions _before_ the hypot, then send the X and Y velocities to the hypot. The hypot is the vector velocity, which is the required spindle velocity (scaled as needed). Other than that, I agree that 3 is the way to go. Regards, John Kasunich - 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
Re: [Emc-users] synchronized axes.
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
Re: [Emc-users] synchronized axes.
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
