swampdonkeykami 13 Posted October 18, 2013 Share Posted October 18, 2013 Hi Guys! I've been toying with an idea, that I didn't think would work, and set up a test jig. Using an air compressor, a solenoid valve, a flow meter and a 43oh I found that we can get a repeatable cylinder position, like +-2.5 mm! The flow meter is measuring the volume of air that we've fed to the cylinder and the 43oh opens or closes a solenoid valve depending on the cylinder position.http://arduinoforgoodnotevil.blogspot.ca/2013/10/accurate-ish-pneumatic-cylinder.html Rickta59, bluehash and chibiace 3 Quote Link to post Share on other sites
bluehash 1,581 Posted October 18, 2013 Share Posted October 18, 2013 Pretty cool! Attaching video: http://youtu.be/Gmt7iVCwDKY Quote Link to post Share on other sites
swampdonkeykami 13 Posted October 18, 2013 Author Share Posted October 18, 2013 Now that we know it works, I'm bustin' out more cylinders and joystick controls! :thumbup: Quote Link to post Share on other sites
chibiace 46 Posted October 18, 2013 Share Posted October 18, 2013 looks dangerous, fantastic! Quote Link to post Share on other sites
t0mpr1c3 91 Posted October 18, 2013 Share Posted October 18, 2013 I like it! Have you tried it under varying loads? Quote Link to post Share on other sites
Rickta59 589 Posted October 18, 2013 Share Posted October 18, 2013 So is going to be part of some gold mining machine? Quote Link to post Share on other sites
swampdonkeykami 13 Posted October 18, 2013 Author Share Posted October 18, 2013 Glad you like! More fun in the works! No, this came out of a gold mining machine. I'm re-purposing for something completely useless. ;-) As for varying loads, yes and no. If you are talking lifts various weight of items, shouldn't make a difference because the cylinder volume is constant. You put in 3 litres of compressed air @ 30psi, the cylinder moves 500mm. You put in 3 litres of compressed air @ 200psi, the cylinder moves 500mm. The trick is, the 43oh needs to return to a known position (full retract, full extend, or limit switch) prior to changing the load. But if the load varies with stroke, like a pivoting boom, then there needs to be some fancy maths to figure it out. Because air is compressible, the 3 litres you put in @ 30psi gets compressed as pressure required to support the load increases. And, it'll be sloppy because air acts like a big spring under accelerating and decelerating loads. But I've got a few tricks up my sleeve to deal with that... Quote Link to post Share on other sites
swampdonkeykami 13 Posted October 18, 2013 Author Share Posted October 18, 2013 *thinking* or we could install a pressure transducer and have the 43oh calculate the volume of air @ X pressure and base all movements on that baseline pressure, then don't need any fancy geometry algorithms for axies! THANKS FOR THE INSPIRATION GUYS!!!!! Quote Link to post Share on other sites
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