>>> This is a pretty neat training gizmo for control loops. Sort of like
>>> the
>>> ball balancer, but better.

>> I considered doing a ball balancer, but I figured this would cost less.

>> For that matter, I really wanted to do an inverted pendulum -- but I
>> couldn't see how to do the mechanism cheaply.

>> The wheel collars stayed tight on the flight home, yet the pot was
>> still
>> punched off the board.  Not by as far -- but all leads broken is still
>> all leads broken.  I suspect that any sort of collar that rides close
>> to
>> the board to limit travel in that direction will either rub or have too
>> much play to be safe -- but I could be wrong.

>> At this point what I see is a choice between some rotational slop
>> between
>> shaft and pot (which messes up the educational value of the thing), the
>> current setup (which leaves it fragile, but possibly manageably so),
>> some
>> sort of a flex coupling or spring (assuming I can figure out how to do
>> that well and cheaply), or some sort of a spring-loaded means of
>> holding
>> the shaft-pot joint to be snug in rotation, but still low friction to
>> axial motion.

>> --
>> Tim Wescott
>> Control system and signal processing consulting www.wescottdesign.com

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