here is a video showing the jumping of the velocity. (we cobbled together an old terco trainer to play with)
http://www.youtube.com/watch?v=4Mz7tzVSsYk&feature=youtu.be here is the little machine running the penguin as fast as it can go.. (with the setting we had) it seems go gain z hight (about .030 each run) - but our wiring is so bad that I am surprised it works as good as it does. http://www.youtube.com/watch?v=Qp0ZpxsgxVs The new tp ran the penguin in 1:40 vs 2:20. (lots of strait lines that run the same with both planners) sam On 03/27/2014 05:48 PM, sa...@empirescreen.com wrote: > one more thing - maximum velocity slider doesn't seem to be obeyed. some of > the time it is - but take the 3dchips and have the feedrate set very high. > now run the maximum velocity slider to say 10 ipm. when it gets to sections > of short line segments - it take off and goes at a much higher feedrate.. > > sam > > > On Wed, 26 Mar 2014 15:03:50 -0500 > sam sokolik <sa...@empirescreen.com> wrote: >> here is 50% (1750mm/min) >> >> http://imagebin.org/301967 >> >> sam >> >> >> On 03/26/2014 02:49 PM, Robert Ellenberg wrote: >>>> One thing I noticed... Lets say we are running that profile at 3500mm/s >>>> and it is dipping like this http://imagebin.org/301375 if you slow the >>>> feedrate down - the dips get scaled also. I would think at 3200mm/min >>>> it would flatten out. :) (probably another nit-pick) >>> That's a good point, it shouldn't scale proportionally at lower feeds. Does >>> that keep happening at slower feeds like 3000 or 2500? If so, it might mean >>> that something's being limited that doesn't need to be. >>> >>> -Rob >>> >>> >>>> sam >>>> >>>> On 3/26/2014 1:27 PM, Robert Ellenberg wrote: >>>>> Hi Sam, >>>>> >>>>> This acceleration limitation is by design, so that the TP can deal with >>>>> tangential and normal acceleration separately. On a circular arc segment, >>>>> the acceleration along the path is limited to 0.5 * a_max. Using the >>>>> pythagorean theorem, the maximum normal acceleration is: >>>>> >>>>> sqrt( a_max^2 - (1/2*a_max) ^2 ) = sqrt(3/2) * a_max ~= .866 * a_max >>>>> >>>>> So, if your maximum axis acceleration is 30 in/sec^2, then the TP only >>>>> moves fast enough around the arc to create 25.98 in/sec^2 of normal >>>>> acceleration. This way, if you have to speed up or slow down during an >>>> arc >>>>> move, the total acceleration it won't exceed the machine maximum. >>>>> >>>>> A good analogy is high-speed cornering with a car on a twisty road. >>>> There's >>>>> a maximum speed you can go around the corner before the tires slip. >>>>> However, if you actually drive at that speed and have to hit the brakes, >>>>> you're in trouble :). So, to be safe, you go a little slower so that you >>>>> can slow down if need be. >>>>> >>>>> The good news is, this particular limit on tangential vs. cornering >>>>> acceleration gets you pretty close to top speed. For example, on a 0.1" >>>>> radius, a max normal acceleration of 26 in/sec^2 gives you a max speed of >>>>> sqrt( 26 in/sec^2 * 0.1 in) ~= 1.61 in/sec. Compare that to 30 in/sec^2, >>>>> which gives you sqrt( 30 in/sec^2 * 0.1 in) ~= 1.73 in/sec (about 7% >>>>> difference). >>>>> >>>>> I just hard-coded this because it seemed to give me the best speed on my >>>>> test runs. Maybe it could be an INI parameter? You could potentially get >>>> a >>>>> little performance from a program with lots of circular arcs by reducing >>>>> the tangential acceleration in favor of normal acceleration. Conversely, >>>>> making tangential and normal acceleration both sqrt(2) * a_max might move >>>>> more quickly in programs with a lot of detail like stellabee1.ngc. >>>>> >>>>> -Rob >>>>> >>>>> On Mon, Mar 24, 2014 at 2:47 PM, sam sokolik <sa...@empirescreen.com> >>>> wrote: >>>>>> I have a question about the acceleration limits. (and I might be >>>>>> nit-picking here) But I have been goofing around with the >>>>>> trochoidal.ngc file from http://www.vagrearg.org/gcmc/trochoidal.ngc.gz >>>>>> >>>>>> I see when I push the velocity up to 3500mm/min - the peak velocity >>>>>> starts to dip (this is with 30in/s^2 acc) >>>>>> >>>>>> http://imagebin.org/301375 >>>>>> >>>>>> but you can see that the acc doesn't get to 30in/s^2 - it seems to peak >>>>>> at about 26 or so. I did play around with the gap freq in the ini file >>>>>> (setting it to my servo period of 1000) and it may have helped just a >>>>>> little bit. >>>>>> >>>>>> http://imagebin.org/301376 (acc peaks just a little higher) >>>>>> >>>>>> is this just a limitation of the whole system? It it still way way >>>>>> better than the current tp - but was wondering what was causing this. >>>>>> >>>>>> sam >>>>>> >>>>>> >>>> ------------------------------------------------------------------------------ >>>>> Learn Graph Databases - Download FREE O'Reilly Book >>>>> "Graph Databases" is the definitive new guide to graph databases and >>>> their >>>>> applications. Written by three acclaimed leaders in the field, >>>>> this first edition is now available. Download your free book today! >>>>> http://p.sf.net/sfu/13534_NeoTech >>>>> _______________________________________________ >>>>> Emc-developers mailing list >>>>> Emc-developers@lists.sourceforge.net >>>>> https://lists.sourceforge.net/lists/listinfo/emc-developers >>>>> >>>>> >>>> >>>> ------------------------------------------------------------------------------ >>>> Learn Graph Databases - Download FREE O'Reilly Book >>>> "Graph Databases" is the definitive new guide to graph databases and their >>>> applications. Written by three acclaimed leaders in the field, >>>> this first edition is now available. Download your free book today! >>>> http://p.sf.net/sfu/13534_NeoTech >>>> _______________________________________________ >>>> Emc-developers mailing list >>>> Emc-developers@lists.sourceforge.net >>>> https://lists.sourceforge.net/lists/listinfo/emc-developers >>>> >>> ------------------------------------------------------------------------------ >>> Learn Graph Databases - Download FREE O'Reilly Book >>> "Graph Databases" is the definitive new guide to graph databases and their >>> applications. Written by three acclaimed leaders in the field, >>> this first edition is now available. Download your free book today! >>> http://p.sf.net/sfu/13534_NeoTech >>> _______________________________________________ >>> Emc-developers mailing list >>> Emc-developers@lists.sourceforge.net >>> https://lists.sourceforge.net/lists/listinfo/emc-developers >>> >> >> ------------------------------------------------------------------------------ >> Learn Graph Databases - Download FREE O'Reilly Book >> "Graph Databases" is the definitive new guide to graph databases and their >> applications. Written by three acclaimed leaders in the field, >> this first edition is now available. Download your free book today! >> http://p.sf.net/sfu/13534_NeoTech >> _______________________________________________ >> Emc-developers mailing list >> Emc-developers@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/emc-developers > > ------------------------------------------------------------------------------ > _______________________________________________ > Emc-developers mailing list > Emc-developers@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-developers > ------------------------------------------------------------------------------ _______________________________________________ Emc-developers mailing list Emc-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-developers
