Re: New technique: three position piston control

In lugnet.technic, Mark Bellis wrote:
> In lugnet.technic, Kevin L. Clague wrote:

<snip>

>>
>> I already have a paper design for a six legged walker with three leg groups
>> using forward/mid/back leg sweeps (what a surprise!)  It walks using a 9 step
>> sequence.  It only uses mid-stop on expansion, but not on contraction.
>>
>> Please let me know what you think.
>>
>> Kev
>
> 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.
>
> Does your centre stop cylinder stop accurately in the same place every time,
> even under different pressure conditions?  I thought if you put a lot of source
> pressure into the cylinder it might overshoot the mid-point, whereas with low
> pressure it would creep up to it.  Accurate repeatable positioning is one of the
> challenges of this scheme.

The center stop is not the same spot when expanding vs. contracting.  I did not
try it at different pressures.  I just pumped a hand pump as fast as I could to
make the sequencer go.

I've not seen it overshoot the mid point.

>
> Mark

Kevin