Re: [CAD_CAM_EDM_DRO] Re: breakout boards plus - hard choice

Peter,

Yeah I do think the unstallable stepper is being developed for the G100. Sounds like a good system. Personally, I'm not sure it's the direction to go though.

If I understand it correctly, current stepper and servo drives are all unstallable in a sense, that they allow a certain following error. The ability of the motors to lag behind the commanded position and not lose position ultimately.

A properly setup and operated system is very reliable in regards to positional accuracy. The only time this is an issue is when some unusual event takes place thereby restricting an axis for whatever reason. Something not anticipated. Analytically, is it best to try and overcome the obstacle, or stop and see what the problem is. The better logic says to stop and see what the problem is. If we're backing out of the driveway and run over the kids bike, do we drop down in a lower gear and over come the increased load :), or do we stop and get the kids bike out, eliminating further damage to his vehicle and our own?

A system like this has some applications, for basic 3 axis cartesian setups, I don't see it.

I know I'm biased in this because I sell the encoder board. And I've been told by many, "thats all it does is stop the machine" Thats by design and decision, not limitation. When Brian Barker and I were discussing the design of the DLL plug in, positional correction on the fly was mentioned. Properly setup digital systems don't need it. Analog systems do. And all hobby and alot of commercial systems nowadays are digital.

Ron






Peter Homann <groups@...> wrote:
Mark,

A couple of things. I believe that the unstallable stepper is designed to work
with the G100 which will slow down the feed rate on all axes together.

If not used in a syncronised system, it could work independently faulting once
the stepper has lost say, 256 steps. This is the same as any servo system.

I don't believe that the intention is that you set the feed rate to warp
factor 9. You would still have to set an appropriate rate. The stepper would
then be able to recover from the occasional lost step.

Cheers,

Peter

Mark Vaughan wrote:

> The worrying bit Graham is while one axis slows, what are the others doing.
>
> To work they all need to be tied together, and by quite a complex set of
> formulae to maintain the shape accuracy.
>
> At present you won't loose steps, but you will still suffer an error in the
> work, so it becomes debatable whether there is any major benefit.
>
>
>
> Regs Mark
>
>
>
> Dr. Mark Vaughan Ph'D. B.Eng. M0VAU
>
> Managing Director
>
> Vaughan Industries Ltd, reg in UK no 2561068
>
> Water Care Technology Ltd, reg in UK no 4129351
>
> Addr Unit3, Sydney House, Blackwater, Truro, Cornwall, TR4 8HH, UK.
> Phone/Fax 44 1872 561288
>
> RSGB DRM111(Cornwall)
>

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