Re: Geckodrive

>
> Yes, what you are describing is adaptive control, it's been around
> since at least the 70's in CNC, perhaps even further back. Some

> the metal cutting CNC machines have this feature (Optionaly), but
> it's application really took off with EDM machines.
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> --- In CAD_CAM_EDM_DRO@yahoogroups.com, "Mariss Freimanis"
> <mariss92705@> wrote:
> >
> > No, the motor does not stall. It is prevented from doing that by
> > monitoring the lag angle and decelerating the rotating magnetic
> field
> > to prevent it from getting more than 1.8 degrees ahead of the
> rotor.
> >
> > The net effect is the motor slows down under heavy load. As it
> does,
> > more torque is available as speed drops until a "balance point"

> > found where available torque equals load torque.
> >
> > Relieve the load torque and the motor accelerates until a new
> balance
> > point is found.
> >
> > The lead/lag angle register is analogous to the position error
> summing
> > node in a classic servo. A step pulse increments this register,
> the
> > encoder count decrements it. The contents of this register is
> input to
> > a PID algorithm; the PID algorithm output then modifies the step
> pulse
> > rate to keep the summing node at a desired constant value.
> >
> > The lead/lag register also is used to increase the
> motor's "stiffness".
> >
> > An open-loop step motor has +/- 1.8 degrees of stiffness. In

> a
> > step motor only delivers its rated holding torque when its shaft
> is
> > displaced 1.8 degrees from its no-load position. The servoed
> response
> > is to "step into" the load, canceling this error. A 500-line
> encoder
> > gives a 10-fold increase in stiffness over an open-loop step

> >
> >
> > Mariss
> > --- In CAD_CAM_EDM_DRO@yahoogroups.com, "lcdpublishing"
> > <lcdpublishing@> wrote:
> > >
> > > Okay, so the motor still stalls like any other stepper system.
> > > However, it tolerates the stall and provides feedback to the
> > > controlling software which would allow for a recovery if in

> the
> > > problem causing the stall is self-correcting?
> > >
> > > It sounds neat, yet impossible at the same time. Either way,

> > > sounds like it has the potential of allowing higher speed
> performance
> > > from stepper systems. Perhaps I should look at this as if it
> were in
> > > an adaptive control system and it would make more sense.
> > >
> > > Sounds cool guys.
> > >
> >
>