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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: 
380 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 (...) (19 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 (...) (19 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 (...) (19 years ago, 28-Sep-05, to lugnet.technic, lugnet.robotics)

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