Another year has gone by so it's time for my annual
robots.net journal entry. :-)
Still no new developments with the simulator, it stabilized
back in '02 with the features I set out to create so I
haven't had much inspiration or motivation to enhance it.
There may be an extension before long to allow other
applications to control simulated robots... but I'm not
promising. Lots of other irons in the fire right now.
Moments ago I beheaded a Hitec 645MG and 5645MG (essentially
the same servo, but the former is analog and the latter
digital) and a Futaba 9252 (digital), and hooked them up to
gear to see how they
would behave in continuous-rotation applications. I have
long theorized that digital servos use PID feedback to get
their improved holding power, and furthermore the "I" term
in the PID equation would render them useless for continuous
rotation. I was wrong.
If there were an I term in the feedback equation, I would
expect the servo motor to accelerate to full speed if the
desired position and actual position were held just slightly
apart for a length of time. However, I was able to make the
motor run at a low speed indefinitely. The Hitec 5645 seems
to have slightly higher proportional feedback than the 645;
the Futaba 9252 has substantially higher proportional gain
(the 'window' that creates variable speed output is quite
narrow by comparison to the others), but there's no evidence
of integral feedback.
I surgicially reattached the heads of the aforementined
servos and I am happy to report that all three patients
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Now, back to robot stuff...