On Sun, 2013-06-09 at 22:05 -0400, Kent A. Reed wrote: > On 6/9/2013 9:08 PM, Jon Elson wrote: > > Gene Heskett wrote: > >> Looking at its voltage output, with the motor disabled so there is no > >> feedback,off = 0.125 volts > >> click fwd button= 0.382 diff = 0.257 > >> click + button = 0.942 diff = 0.560 > >> click + again = 1.584 diff = 0.642 > >> click + again = 2.302 diff = 0.718 > >> click + again = 3.094 diff = 0.792 > >> click + again = 3.970 diff = 0.876 > >> click + again = 4.940 diff = 0.970 > >> click + again = 6.04 diff = 1.100 > >> click + again = 7.33 diff = 1.29 > >> click + again = 8.88 diff = 1.55 > >> click + again = 9.90 diff = 1.02 > > URK! It isn't even monotonic! That is harder to fix with a > > piecewise-linear > > interpolation. (Some simplistic codes won't handle that.) > > > > > > Ummm, I expect you mean the differences aren't monotonic, Jon. > > Actually, plotting Gene's data as a set of twelve points X, V where X is > the number of clicks, I get a pretty decent graph --- looks like a > parabolic curve opening upward, with a bit of a burble in the next to > last point (or last two depending on how you look at data). > > Trying a second-order curve fit (using the free tool simfit, but there's > lots of other tools) got me a decent looking result with a plot of > residuals that also gives the impression that the last two points are > questionable compared to the rest. > > I don't chose simply to post the results because I don't believe any > single experimental run is sufficient. Repeat this experiment three or > more times, Gene, so we can begin to get an idea of the quality of the > data and then we can talk. > > Regards, > Kent
Except for the last point that looks like it should fit as a 2nd order polynomial. Since we can to a considerable amount of calculation between servo cycles calculating a simple polynomial should be simple and fast. Dave > > ------------------------------------------------------------------------------ > How ServiceNow helps IT people transform IT departments: > 1. A cloud service to automate IT design, transition and operations > 2. Dashboards that offer high-level views of enterprise services > 3. A single system of record for all IT processes > http://p.sf.net/sfu/servicenow-d2d-j > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users ------------------------------------------------------------------------------ How ServiceNow helps IT people transform IT departments: 1. A cloud service to automate IT design, transition and operations 2. Dashboards that offer high-level views of enterprise services 3. A single system of record for all IT processes http://p.sf.net/sfu/servicenow-d2d-j _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
