Feedforward conversation

[From Rick Marken (931108.1300)]

CHUCK TUCKER (931107)--

I hope that this discussion of Feedback/Feedforward will be
carried on to some reasonable conclusion resulting in an
agreement.

Me too. But that will only happen if everyone who doesn't agree
with me ends up agreeing with me. So it's up to them if they want
to reach a reasonable conclusion (hee hee).

I certainly believe it is possible to construct
a machine which has both open and closed looped parts to it.

Everyone already agrees on that. The question is, how much of what
we call "behavior" is open loop. This is a job for "the test".
The term "behavior" typically refers to the activity of variables in
the environment (car speed, gas pedal position, etc). If the variable
passes the test, then it is controlled and must be part of a closed
loop control system. If it fails the test then it is not controlled;
the value of the variable is determined by "feedfoward" (open loop)
processes.

Since our cars are quite handy and always seem to creep into
our examples

Oops, car creep in paragraph above.

perhaps someone can point out that some parts
are open while other are closed looped.

Most "parts" (I assume you mean relationships between variables) of a
car are open loop (for example, the relationship between steering wheel
angle and tire angle, cam shaft angle and height of the valves, etc).
In the driving example above (which includes the car AND the driver)
you would probably find that gas pedal position is determined open
loop while car speed is determined closed loop. Gas pedal position
is an uncontrolled variable that also happens to be part of a
closed loop of relationships between variables.

My favorite example
recently are the windshield wipers which appear to be closed
looped but are not at least on my car.

What is it that appears closed loop about your windshield wipers?

Best

Rick