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Subject: 
Re: SSC (was Re: Best pneumatic hexapod yet!)
Newsgroups: 
lugnet.technic, lugnet.robotics
Date: 
Mon, 1 Aug 2005 16:20:10 GMT
Viewed: 
241 times
  
In lugnet.technic, Steve Hassenplug wrote:
On Sun, July 31, 2005 9:56 am, Kevin L. Clague wrote:
Will this new central timing circuit allow you to attach touch sensors, so, if you
wanted, you could track the state of the walker with an RCX?

Will this be needed if we always have at least four feet locked into weight
bearing state at a time?  I've incorporated your folding/locking table leg into
this walker.

Will it be necessary to switch anything at a specific time?

No.  The central timer is unchanged by switching from forward to reverse, or
walk to turn.

The things that do change behavior are the leg sweep pistons.  These will do
their best to accommidate the change, which may not have any affect until the
feet are lifted.


For example, if SSC is walking forward, and it takes 3/4 of a step, then levers are
flipped to make it turn (which would be reversing the legs on one side), to complete
the "current" step, one set of legs must go 1/4 forward, while the other side must
go 3/4 of a step backward.

Is that OK with your current logic?

Yes.  It is fine.  The muscle pistons are all that are affected, and they are
not instrumented with switches.


If these things are OK, the only thing that may still be good to know is when all
legs are down.  That way it would look better when it stops walking.  (stand still
with all legs down)

Well, that is an artistic/stylistic point of view.

I think that for long term rest state it is less stress on the LEGO if all feet
are down, but I don't know that I agree that it will look better ;^)


Steve

I have all the leg lifting working, and the leg sweeping pistons are in place.
My implementation of leg sweep timing is wrong, but that should be easy to
diagnose.

Right now, it requires very high pressure to make the timing circuit go, because
I have 5 swtiches per large piston.  I may try to make the ratio more like 5
switches for 2 pistons.....  this should reduce the processure needed quite a
bit.

At these pressures, expanding pistons do better than contracting pistons,
because the cylinder face used for expansion has more area than the cylider face
of contraction (hint: force = pressure times area).

Kevin



Message has 1 Reply:
  Re: SSC (was Re: Best pneumatic hexapod yet!)
 
(...) I should say it would look more 'natural'. How easy will it be to install a normally closed (while the foot is in the air) touch sensor in the foot? Will the feet be required to do much rotating and/or sliding while taking a step? (I assume it (...) (19 years ago, 1-Aug-05, to lugnet.technic, lugnet.robotics)

Message is in Reply To:
  SSC (was Re: Best pneumatic hexapod yet!)
 
(...) Will it be necessary to switch anything at a specific time? For example, if SSC is walking forward, and it takes 3/4 of a step, then levers are flipped to make it turn (which would be reversing the legs on one side), to complete the "current" (...) (19 years ago, 1-Aug-05, to lugnet.technic, lugnet.robotics)

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