--- Roman Black <fastvid@EZY.NET.AU> escribis: > >
>
> Hi Carlos! :o)
> You will find this is MUCH harder to do with a
> constant magnetic field. It is a lot easier if
> you turn the top (pull) magnet on and off very
> fast and there is some tiny movement of the ball.
> Commercial "desk toy" type designs usually oscillate
> fast enough that it is not obvious until you
> examine it very close.
> -Roman

Hi again Roman, it is nice to find you here...

About the little thing I have been doing, so you are
proposing to make a sort of "on/off" control? Do you
mean like producing and average magnetic field product
of turning off and on the electromagnete with a
constant current and a constant freq? I suposse that
the big trouble about this is finding out the proper
values for current and frequency to make the ball
float... In the other hand no feedback sensors (i.e.
the postion sensors) would be needed so it would be an
open loop system; would this guarantee (not sure I
wrote it right!) stability in the system?
   Olin Lathrop proposed to me that I should change
the PID focus and use an scheme based on look up
tables because the magnetic fields isn4t as linear as
the position. What do you think about that?
                         thanx for your time,
                                        Carlos

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