Re: [CAD_CAM_EDM_DRO] Comments from expert PID programmers?

Peter Reilley wrote:

>A more mathematical answer is that backlash represents
>a step function in the control loop. A step function
>contains frequency elements from DC to infinity.
>You simply cannot create a compensating control
>function in the real world that handle that wide
>a frequency range.
>
>
>

I'm pretty much in agreement with you, Pete. Even neglecting
that the cutting forces can grab the table away from the CNC
control for the distance of the backlash, which can be a REAL
problem, I just don't think that software can fix, after the fact,
that there is a loss of connection between the CNC control and
the table position. You can try all you want to "mask" the backlash,
but it will still rear its ugly head from time to time, and mar the parts
you are trying to make. Best solution is to minimize the backlash
at the very beginning of machine construction.

Jon