Test for Open-Loop System

[From Bill Powers (931110.1930 MST)]

It's interesting how Rick Marken, Tom Bourbon, and I have
independently come up with many of the same arguments concerning
feedforward and/or open-loop behavior.

The most important one right now is Rick's suggestion of a Test
for the Open-Loop System. It's actually just the good old Test,
when you think about it: if the Test is failed, the behavior is,
for all we know, open-loop.

I strongly back Rick's suggestion that all claims about open-loop
behavior be backed up by a real test. Thought-experiments that
demonstrate what "everyone knows" are not enough.



Bill P.