Surveyors know you need a rigid,
stable platform for level measurements. But in the world of LEGO that
doesn't exist. Anything you could build to make adjustments with pivot points,
levers and gears will have lots of looseness. For convenience I call it slop
(as in sloppy fit). The biggest problem is how to deal with slop. |
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Another problem is that when you reach near
horizontal the adjustment becomes ultra sensitive. If you sneeze the bubble
jumps to the other end of the tube. You need tiny adjustments with ample settling
time for bubble movement or it will never come to center. |
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I have two platforms, at right angles, for the XZ
and YZ axes. Each one is driven by a double worm and wheel (shown left) each at
24:1 ratio with final gearing 576:1. The program runs each motor 1/100 sec and
stops 10/100 sec to slow the process even more, and the stepping-motor action provides a
gentle vibration to assist the assembly in settling to the bottom of the slop.
Adjustment is always downward. This approach has solved the two major
problems: slop and sensitivity. |
As you will see in the next page, I have used RoboLab
software. Because it is icon-based, some think it is 'not real code' and 'OK for
children'. But they might not know that RoboLab was written in National Instruments
LabVIEW. Think of it: A program used to write other programs! If you
have a copy of RoboLab and want an outside-the-box experience, press the 'single step'
button in the top menu bar. You will enter one of the icons (say) a task split, and
suddenly a series of windows open into the hidden structure of the icon, perhaps twenty
steps to get through it, letting you peek inside LabVIEW, the elegant parent program.
And so, on to the
software...!!
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