CRAZY STUFF 3.2

Hi,

I know I might give you frustration and headaches :) I already
have described 5-6 different designs. Not easy to follow. And now
I add something more in this debate.

First of all, - I think the best thing is to just try to describe
and "dream" a little. The bits and pieces will follow, if it is
possible to narrow it down to the functions that is needed. Some
simple block diagrams could be a nice start.

The wrong thing, is that I have done my time with step motors, and
my main thing now is servo drives. Else I would be designing right
now :) But I know that there is a lot of you out there that can
do this even better than me, so I just throw in some ideas. ( and
I lack machine experience )

Multiple axis:
----------

In servo systems, with separate controllers, it is often common
to have some monitor that will keep track of the update time. Say
you have 3 axis, x, y, z. They will move on a trajectory from one
point to another in 3 dimensions. If you have just a start point
and an end point, then the velocity needs to be very accurate,
else 2 of the axis may reach the destinations long before the last
axis arrive. Not good. So it is often better to divide this up
in smaller segments. If one axis lags, then the speed is increased
a bit on the next segment. Or one axis is slowed down a bit.
There is some close coupling between them. There is several ways
to do this control, one is to measure when each axis calls for an
update. If they differ to much in time, the system trips and
stop. Indicating that these servos need tuning. Some even
employ some tuning in software.

If you loose steps one one axis in a step motor system, what then
?
The question is simply - should there be a mechanism that will
interconnect the different axis, like explained above ?

//ARNE