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Mario wrote:
> Paolo Masetti gave everybody a humiliating lesson: his vehicle ran the path
> in some hundreds less than 10 seconds, at the astonishing speed of 70cm/s
> (2.3 feet/s). The second best robot took two and a half that time.
> While running at that speed his robot was playing the Indiana Jones movie
> theme too :-)
<snip>
> But the most important point, IMO, is that Paolo's robot was the only one
> that ran a legOs program. I absolutely don't want to say that Paolo won
> *because* he used legOs, I just want to say his performance was *made
> possible* by legOs, and in particular by its faster sensor sampling rate.
Alternative firmware is crucial to developing high-performance bots. The
core sampling rate of the RCX firmware is once every 3 msec, which is pretty
fast. I'm not sure of the max rate that legOS allows. At that rate, the line
is sampled every (.70/333) ~= 2mm or .080 in. This is MORE than enough
resolution for the problem, so the real benefit of alternative firmware is not
the sampling speed (IMHO) but the *reaction* to the results of the sampling.
The standard firmware must laboriously grind through all of the opcodes
and watches and evaluate conditions before updating its outputs. Users of
alternative firmware can optimize this part of the process and make a
routine that does nothing but adjust steering based on the light sensor, with
no need to update system timers and other niceties.
I'll bet that Paolo spent a LOT of time tuning his algorithms to close
the feedback loop without too much oscillation while still maintaining good
response, which is one of the classic problems in control systems theory.
Great work, Paolo, and thanks for telling us about it, Mario!
Cheers,
Ralph Hempel - P.Eng
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Check out pbFORTH for LEGO Mindstorms at:
<http://www.hempeldesigngroup.com/lego/pbFORTH>
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Reply to: rhempel at bmts dot com
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| Yesterday, Sunday 26th March, we had our 4th Italian Legofest. This time our traditional robotic contest was about line following, and 10 peopled compared their ideas, their knowledge and their ability running their robots for maximum speed on a 7m (...) (25 years ago, 27-Mar-00, to lugnet.robotics, lugnet.robotics.rcx.legos) !
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