Re: [Emc-developers] announcement OpenCN, a new fork of LinuxCNC --> Precalculations

[Herzog R. <Rao...@he...>]

Hi Andrew,

yes, the double feedback loop (from rotary and linear encoders) are completely in the TRIAMEC drives.

At the moment, OpenCN only supports EtherCat, no support for MESA boards.

The "micro5" is commercialized (MECATIS and KUMMER) with a BECKHOFF (ISG) CNC and TRIAMEC drives. 

best regards,

Raoul

-----Message d'origine-----
De : Andrew <pk...@gm...> 
Envoyé : samedi 23 novembre 2019 16:51
À : EMC developers <emc...@li...>
Objet : Re: [Emc-developers] announcement OpenCN, a new fork of LinuxCNC --> Precalculations

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 <Rao...@he...> 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 <pk...@gm...>
> Envoyé : samedi 23 novembre 2019 12:24 À : EMC developers 
> <emc...@li...>
> 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 <Rao...@he...> 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 <nic...@gm...> Envoyé : samedi 23 novembre 
> > 2019 10:51 À : EMC developers <emc...@li...>
> > 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
> > Emc...@li...
> > https://lists.sourceforge.net/lists/listinfo/emc-developers
> >
> >
> > _______________________________________________
> > Emc-developers mailing list
> > Emc...@li...
> > https://lists.sourceforge.net/lists/listinfo/emc-developers
> >
>
> _______________________________________________
> Emc-developers mailing list
> Emc...@li...
> https://lists.sourceforge.net/lists/listinfo/emc-developers
>
> _______________________________________________
> Emc-developers mailing list
> Emc...@li...
> https://lists.sourceforge.net/lists/listinfo/emc-developers
>

_______________________________________________
Emc-developers mailing list
Emc...@li...
https://lists.sourceforge.net/lists/listinfo/emc-developers