Dear Raoul, Of course I understand that. Why would you need the new planner otherwise? ) But double feedback loop is completely in the drives, right?
OpenCN seems very interesting, but can it support another protocols besides EtherCAT? Does it still support MESA boards? Those micro3 / micro5 milling machines are quite cool. Which CNC does they have originally? Or you made OpenCN exactly for them? I suppose that a brand 5-axis CNC controller costs quite a lot. сб, 23 лист. 2019 о 13:43 Herzog Raoul <[email protected]> пише: > dear Andrew, > > The RS274 interpreter is still the original, important concepts like HAL, > pins etc, are still there. > > Even with high end drives, you cannot simply stream position data, the > reference signals for each drive *must* respect the physical constraints > regarding max jerk, max acceleration and max speed ! > > Important for understanding : there is NOT ANY trajectory planning INSIDE > the drive, only feedback loops and feedforward. > > best regards, > > Raoul > > -----Message d'origine----- > De : Andrew <[email protected]> > Envoyé : samedi 23 novembre 2019 12:24 > À : EMC developers <[email protected]> > Objet : Re: [Emc-developers] announcement OpenCN, a new fork of LinuxCNC > --> Precalculations > > Just wondering what's left from LinuxCNC there ) With such intelligent > servo drives you just have to stream the position data (you made the new TP > for that!). > Do you use Ethercat I/O too? > > сб, 23 лист. 2019 о 12:17 Herzog Raoul <[email protected]> пише: > > > dear Nicklas, > > > > there is no feedback control loop in OpenCN. > > Feedback and Feedforward is only inside the drives. > > > > We use TSD80E drives from the manufacturer Triamec ( > > https://www.triamec.com/de/triamec-servo-drives.html). > > The sampling frequency for the PWM, current control loop and position > > control loop is 100 kHz ! > > The setpoint values coming from EtherCat at a rate of 10 kHz are fine > > interpolated in the drive and upsampled to 100 kHz. > > > > One remark regarding our feedrate planning. > > At any time, at least one of the constraints is "active", meaning that > > either the max jerk is delivered, or the max acceleration, or the max > speed. > > Sometimes this is called "Bangbang", maybe a misleading term since > > there are no jumps in acceleration. > > Time optimality automatically leads to this "Bangbang" property. > > > > best regards, > > > > Raoul > > > > -----Message d'origine----- > > De : N <[email protected]> > > Envoyé : samedi 23 novembre 2019 10:51 À : EMC developers > > <[email protected]> > > Objet : Re: [Emc-developers] announcement OpenCN, a new fork of > > LinuxCNC > > --> Precalculations > > > > > dear Nicklas, > > > > > > of course, feedforwards are utilized (and well parametrized) in the > > *drives*, otherwise excessive tracking errors appear. > > > > > > But this is done in the *drive*, *not* in OpenCN. > > > OpenCN calculates physically realizable setpoint values (according > > > to > > "optimal control theory"). > > > > Sounds really good. Physical realisable will be movement calculated > > with feedforward of maximum and minimum voltage with a perfect model, > > sounds simple but to calculate then it is time to slow down to exactly > > hit a point running at the limits is suprisingly hard to get correct for > all cases. > > > > Then there must be some room for the control law. You have gone > > further and included unperfect model and dynamics from the feedback in > > some way or other? > > > > > > Regards Nicklas Karlsson > > > > > > _______________________________________________ > > Emc-developers mailing list > > [email protected] > > https://lists.sourceforge.net/lists/listinfo/emc-developers > > > > > > _______________________________________________ > > Emc-developers mailing list > > [email protected] > > https://lists.sourceforge.net/lists/listinfo/emc-developers > > > > _______________________________________________ > Emc-developers mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-developers > > _______________________________________________ > Emc-developers mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-developers > _______________________________________________ Emc-developers mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-developers
