LEGO TECHNIC : 14651

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Subject:	Re: New technique: three position piston control
Newsgroups:	lugnet.technic, lugnet.robotics
Date:	Wed, 28 Sep 2005 23:47:45 GMT
Viewed:	9879 times

In lugnet.technic, Mark Bellis wrote: > In lugnet.technic, Kevin L. Clague wrote: > > In lugnet.technic, Kevin L. Clague wrote: > > > In lugnet.technic, Mark Bellis wrote: > > > > > > <snip> > > > > > > > > Interesting stuff! Should make walkers move more smoothly, with the possibility > > > > of more groups of legs. The trick will then be reversing all the groups, since > > > > it was easier with just two, using two polarity reversers. > > > > > > > > I have a centre-stop mechanism for pneumatic steering for a JCB. It's not part > > > > of an automatic system though, since I don't yet have an application for that. > > > > > > Was this single or dual piston? > > > > Mark, > > Did I miss your answer on this? > > Kev > > No, I was so busy at work that I missed a couple of days online! > > I had a look at both, but a dual piston scheme works better for steering because > of equalising the piston area and pushing at least 3 switches. In fact I have > two cylinders in parallel at the moment. One problem I can foresee with that is > that there is a net force towards the middle due to the auto-expansion effect, > so the mechanism in the middle has to have good compressive strength. <snip> I used some axle joints to optimise cylinder position limiting in normal logic > systems (without offset switches) in my Octopus arm. The base of one axle hole > is on the end switch and the other end hits the top of the cylinder, limiting > its contraction to the right amount. This reduces air usage on the logic board, > speeding things up a bit. Do you have a website where I can peruse your work? > > Mark

Message has 2 Replies:

		Re: New technique: three position piston control
In lugnet.technic, Kevin L. Clague wrote: (SNIP) (...) Sadly not, though I'll upload a lot more to my Brickshelf once my digital camera arrives. That will be better than circuits for explaining the positions of offset switches. I had also planned to (...) (21 years ago, 30-Sep-05, to lugnet.technic, lugnet.robotics)

		New technique: Cascaded Trinary Pneumatics (aka mid-stop)
(...) I have succeeded in directly cascading trinary pneumatic stages (where cylinders stop in the middle). This is a direct development of my mid-stop pneumatic JCB steering mechanism, which I first described here two years ago: (URL) (second (...) (21 years ago, 3-Oct-05, to lugnet.technic, lugnet.robotics, lugnet.announce.moc, lugnet.loc.uk)

Message is in Reply To:

		Re: New technique: three position piston control
(...) No, I was so busy at work that I missed a couple of days online! I had a look at both, but a dual piston scheme works better for steering because of equalising the piston area and pushing at least 3 switches. In fact I have two cylinders in (...) (21 years ago, 28-Sep-05, to lugnet.technic, lugnet.robotics)

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