Good catch! It wasn't checking the slider max velocity (tp.vLimit) when doing ramped velocity, so those sections ran at full speed. The latest push to the RC3 branch should fix that.
On Thu, Mar 27, 2014 at 9:59 PM, sam sokolik <sa...@empirescreen.com> wrote: > 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 > ------------------------------------------------------------------------------ _______________________________________________ Emc-developers mailing list Emc-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-developers
