Continuously Variable LEGO Pneumatics Tutorial

[appleintosh]

Why not use a Lego compressor instead of the one you have

[TheBlacksabbathfan9]

That's genius!! I always just steadily moved the switch until the piston startingoving very slow and got to the proper position

[mbellisbrickmocs]

See also pictures and information in my brick shelf gallery.

search for user: mbellis

folder: Technic, Pneumatics, Cont-var-pneu-ctrl

[Zblj1987]

Great idea! But why does the motor have to turn valves?

[mbellisbrickmocs]

The motor dither overcomes stiction in the valves and cylinder and alternates pressure and air leakage from both sides of the cylinder when it is in the commanded position, keeping it actively in position.

The dither is for dynamic response. A Servo Pressure Regulator in industry performs a similar function.

[RANDOMFISHYFACE]

awesome

[Parax77]

Thanks for the very useful Video! nice to see how it all works. far better than just the description.

Nice system. wonder if you could combine the dither motor with a lego compressor!

[mbellisbrickmocs]

:-)

A compressor from the crank to the red beam (all sliding) needs to pump air equally at both ends of the dither (=2 mini compressors as a flat-2 engine), else the pressure output would bias 1 way (could be useful as a fail safe, as in industry).

Best to have excess air at pump freq > dither, for dynamic response. Industrial fuel/oil systems are like this.

Also best not to load the dither motor. 240rpm >> cylinder response. Slower or synchronised and cyl might oscillate at dither freq.