Tuesdsy-02-03-2004

Right o...
work on actually building j5 has come nearly to a standstill.

Work on a couple of other projects hase taken over at the moment...

One of the projects... involving air muscles... has show some suprising and useful data.
The air muscle's i've been making have some useful charecteristics.
The narrower the braided sleeving and tube, the more the air pressure inflating the muscle has to work to overcome the intial tension in the rubber tube and sleeving that make the muscle expand.

It appears that the fatter an air muscle is, the more effeiciently the compressed air converted to lifting power... i.e. a short fat muscle is more powerful than long thin muscle that uses the same quantity of air to become fully inflated. The fat muscle is able to lift more weight over a shorter distance than the thin muscle...
A comparison to the different capabilities of thin and fat air muscles can bee seen in the build difference between a sprinter and a marathon runner!

I've got some nice big 50mm sleeving on order... to be used as the casing for J5's air storage :)
The 50mm sleeving expands to 73mm... and with a 30mm inner tube, pumped up, it would give around 22cc of pressurised air per cm height.

Air system schematic
Click to enlarge in a new window

The schematic above show my idea for recouping the already pressurised air.
The compressor (1) charges the high pressure tank (2).
Both the high pressure tank (2) and low pressure tank (5) have a pressure sensor that relays information to an RCX.
The RCX controls the compressor and the compressor's inlet valve (6).
The pneumatic device (4) is inflated or deflated by the control valves (3).

The RCX controlling the compressor decides whether to draw fresh air or recouped air depending on the pressure difference between the high pressure and low pressure tanks.
The RCX also allows the low pressure tank to be vented should the high pressure tank be full via the inlet valve (6).

I'm going to try and adopt this approach mainly to try and conserve battery power.

All i have to do now is construct everything!

I've been researching the air pressure sensor electronics... and am going to try building the circuit later today :)

The electronic air switch didn't work... it's got to be bigger, with lots of coils... 300+!

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This page is part of a diary of the design and build of my Lego Mindstorms robot J5 (based on Johnny Five from the film short Circuit.)
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