Eric H. Johnson wrote: > The table has conventional X and Y axes, Z is performed pneumatically with > just an up and down position. The A or rotational axis should orient the > knife tangent to the direction of motion defined by X and Y.
If you treat the knife rotation as a proper axis (controlled by the emc2 motion planner), then you'd program the angle along with the rest of your G-code. It might be simpler to use the X and Y velocity estimate and some HAL glue to compute the current motion angle, and output that to the motor controlling the knife angle, without involving the higher layers. > 1> It needs to look back far enough in time while the system is in motion to > get a position enough different from the current position to calculate a > valid slope. Update rates of 1ms or faster for the servo task may result in > only an encoder tic or two difference, which likely would be too inaccurate > to calculate a valid tangent. For my application an error of even +/- a > couple degrees is tolerable, but certainly the closer the better. If you have encoders on X and Y, i think the velocity estimate is what you're after here. > 3> If the vector angle defined between two vectors exceeds a specified > angle, the head needs to lift, rotate to the new angle, and then drop as > there is only so far the head can turn within the material being cut. > Currently I don't see a way to do this automatically within the kinematics > and am considering using a preprocessor to insert the commands for these > head lifts. I could use M3 / M5 to both start and stop the ultrasonics and > perform the head lift. The first choice you have to make is if the knife angle is in the G-code (as you desribe here) or computed dynamically while the program runs (as you've described elsewhere). -- Sebastian Kuzminsky ------------------------------------------------------------------------------ This SF.net email is sponsored by: SourcForge Community SourceForge wants to tell your story. http://p.sf.net/sfu/sf-spreadtheword _______________________________________________ Emc-developers mailing list Emc-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-developers
