One more - de-accelerating... http://electronicsam.com/images/emco/betterstep_de-accelerating.png
(full step on left - half step on right) On 7/19/2013 8:34 AM, sam sokolik wrote: > A little tweaking - better alignment I think. (not that it was causing > issues - so far so good) > > http://www.electronicsam.com/images/emco/betterstep.png > > left side half step - right side full step. (triggered by a velocity > threshold.. - xswitch) > > > On 7/18/2013 4:49 PM, Marcus Bowman wrote: >> On 18 Jul 2013, at 22:15, sam sokolik wrote: >> >>> So - as far as I can tell - the original control did 1/2 stepping up to >>> about 19ipm - then full stepping from there to 30ipm. Now the lathe >>> runs fine on full stepping from 0 to 40 (maybe 45)ipm. Half stepping >>> only works well up to 20ipm-ish. (stalls above that) >>> >>> But why stop there.. >>> >>> I started thinking about if linuxcnc could do that.... (without coding >>> anything) >>> >>> A couple advantages of halfstepping.. >>> 1 higher resolution 0.000273403/step vs 0.000546806 per step >>> 2 reduced resonance.. (I have not run into this with full stepping on >>> the lathe) >>> >>> Then at normal cutting speeds - < 16ipm you get a higher resolution. >>> >>> So why not have 2 stepgens running. One that half steps (type 9) with >>> input scale of 3657.6073152 and the other full stepping (type 6) with a >>> scale of 1828.8036576 (lathe calculation - metric screws) >>> Then switch between the two stepgens at a specific feed (I picked 16ipm >>> with a hysteresis of 1ipm) >> Nice. >> That's pretty much what the Gecko drives do when they morph, I think. Works >> well. >> >> http://www.geckodrive.com/support/application-notes/step-drives/how-morphing-works.html >> >> But your method is simpler and much cheaper. >> >> Marcus >> >>> All I can say is - HAL IS AWESOME >>> I setup a Lut5 with Jeff E's help (thanks jeff!) that switches the >>> printer port between the 2 stepgens. >>> A offset componant was used between the 2 stepgens to better align the >>> phasing. (not tweeked 100% yet) but we jogged it around - could not >>> tell that it was switching between the 2 stepgens and it always came >>> back to 0. >>> there is a bit more than that.. (ddt for calculating the axis velocity, >>> abs of that, comp w/hystorisis, and stuff I have forgotten already.) >>> >>> >>> And here is a halscope capture. Left side is halfstepping - right side >>> is full stepping. The trigger is the velocity threshold. >>> http://www.electronicsam.com/images/emco/Screenshot.png >>> >>> I think the offset could be tweaked more scientifically to maybe get rid >>> of the blip. But as it is running the 4 phases directly - it didn't >>> seem to effect the motion. >>> >>> here is the initial configs. >>> >>> http://www.electronicsam.com/images/emco/linuxcnc_configs/full-half_step_test/ >>> >>> again - jmk and everyone that has worked on hal - Very very awesome work! >>> >>> sam >>> >>> >> ------------------------------------------------------------------------------ >> See everything from the browser to the database with AppDynamics >> Get end-to-end visibility with application monitoring from AppDynamics >> Isolate bottlenecks and diagnose root cause in seconds. >> Start your free trial of AppDynamics Pro today! >> http://pubads.g.doubleclick.net/gampad/clk?id=48808831&iu=/4140/ostg.clktrk >> _______________________________________________ >> Emc-users mailing list >> [email protected] >> https://lists.sourceforge.net/lists/listinfo/emc-users >> >> > > ------------------------------------------------------------------------------ > See everything from the browser to the database with AppDynamics > Get end-to-end visibility with application monitoring from AppDynamics > Isolate bottlenecks and diagnose root cause in seconds. > Start your free trial of AppDynamics Pro today! > http://pubads.g.doubleclick.net/gampad/clk?id=48808831&iu=/4140/ostg.clktrk > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > > ------------------------------------------------------------------------------ See everything from the browser to the database with AppDynamics Get end-to-end visibility with application monitoring from AppDynamics Isolate bottlenecks and diagnose root cause in seconds. Start your free trial of AppDynamics Pro today! http://pubads.g.doubleclick.net/gampad/clk?id=48808831&iu=/4140/ostg.clktrk _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
