Monthly Archives: May 2013

Motion Tests Day 12

First we tested the convoluted bellows with an existing 500X unit (20 SCFM). The inflation speed was acceptable for the money it would save, but the deflation speed is too slow due to the small body ports.

Second we tested the bellows with the M2d proportional valve (60 SCFM). It isn’t a closed-loop system so we can’t control the pressure and the M2d is half wasted because it is meant for double-acting actuators.

So in the end I think the E22 (100 SCFM) will be more than enough and it has full 1/2 FNPT exhaust and is about $200 cheaper than the M2d. I will install the 500X units temporarily for testing and so I can lift the platform up and work underneath without jacks.

Third Time’s a Charm

Over the past 3 weeks I have completely gutted the existing motion control platform and rebuilt it using convoluted bellows. One structural change was made with the platform itself in the front right corner to provide bolt holes for the front right bellow.

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The bellows are capable of lifting 4000 pounds EACH. The question is how quickly I can inflate and deflate them. I have my eye on the Numatics E22 but none of the ones on eBay currently support the analog input variant. I will be conducting tests on the rear right bellow using a ControlAir 500X.

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Only other thing we are waiting for is 3 inch aluminum extrusions to make a base frame for the platform to rest on when not in operation (otherwise we would compress the bellows beyond their design limit of 2.8 inches).

Motion Tests Day 11

It has been almost 7 months since I fired up the compressor and performed some PID loop tests.  Everything powered up except this one USB hub (cheap Chinese crap).

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Overall I am very concerned about moving the stuff out of the basement and onto the trailer at this point.  It still seems very squirrely and unstable for where we should be at.

I am sorry that I resold my convoluted bellows because I am thinking that is a better solution at this point even if we are only looking at 10 degrees of roll/pitch and 7″ heave.  The biggest issue I had back when I tested them is that, because of the volume, it took too long to fill.  But now I am using a bigger compressor, larger diameter lines, and control valves that can deliver up to 60 SCFM.

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I went ahead and acquired an Air Lift Dominator 2600 on eBay for $70 with free shipping so I can run tests again.  I am not sure if I will be able to make it work with the proportional flow controller or if I need something like this proportional pressure controller.

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Worst case scenario would be to build a frame overhead and apply downward force against a spring assembly which is what I did with the Audrey.