Re: [CAD_CAM_EDM_DRO] CNC hydraulic test

----- Original Message -----
From: "Sven Peter, TAD S.A." <peteryco@...>

> Hello Friends,
> For years I dreamed of converting the hydraulic control of
> my copy lathe into CNC.
> Right now I have 2 electronically driven proportional valves
> sitting on my table together with the driver boards.
> The client permits me to make a test for my project before I shall
> install them in his machine.
> The input is -10V...0V...+10VDC but I have no computer with interface
> cards.
> Has somebody an idea how I could make me a simple test set-up to find
> out
> if these proportional valves would do an acceptable job in an CNC
> application?

The problem with hydraulics is that they are open loop unstable, and capable
of
exerting large forces. I have had good luck with force feedback, and no
luck
at all with position feedback, but then again, my control system is for
force feedback,
so I wasn't working that hard on position feedback.
The thing about it is that you need some sort of position feedback with good
precision.
LVDT's don't give good precision in combination with long throws.

My thought is that if you have good position feedback, the control system is
not that
big a deal.
Eric