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Subject: 
Re: SSClagorpion - Another creature - Greene Scorp
Newsgroups: 
lugnet.technic
Date: 
Wed, 19 Jan 2005 04:46:55 GMT
Viewed: 
27371 times
  
In lugnet.technic, Joseph Greene wrote:
In lugnet.technic, Kevin L. Clague wrote:
<snip>
- The compressor (on top) uses 12 small cylinders
http://www.brickshelf.com/cgi-bin/gallery.cgi?i=551846

Wonderfully compact.

Almost as compact as my radial.. which I've  developed /developing 3 and 6
cylinder versions as well.. the 3cyl radial is 12x13x4 studs and can easily be
run with any motor (even the micro), but the 9V RC motor seems to eat batteries
at a rate of a 6pack per 5 minutes, however it produces roughly 60 rpm on the 2
cylinder pneumatic wheel (steam engine style from Dr Soh's site).

Awesome.


<snip>

- The leg pneumatics are driven from cams, which run off the main motors.  So the
forward/back motion would be sync-ed with the up/down via cams.  Springs are used to
keep the switches against the cams

There does not seem to be any guaranteed synchronization between the up down
mechanism and the forward back.  Slow pistons might not hit the ground before
the front back transistions start.

I'm working on and 8 stage..
legs operating in 2  sets of 4 (A and B) with 2 motions each (Up/Down
Forward/Reverse) with control switches (SW1-4 Extended/Retracted).. :
AD -> SW1 Ext ->
AF -> SW2 Ext ->
BU -> SW3 Ext ->
BR -> SW4 Ext ->
BD -> SW3 Ret ->
BF -> SW4 Ret ->
AU -> SW1 Ret ->
AR -> SW2 Ret ->
AD

Are the down legs coming up at the same time as the up legs are coming down?

Sclagorpion will have all 8 legs down, then pick four of them up, shift, and put
them back down before lifting the other four.  This way the body does not go up
and down as part of the walking cycle...



The idea being that each switch consists of 4 small cylinders, no 1 of which can
flip a pneumatic switch by itself (at least non of mine seem to be able to),

I have had luck with two small pistons flipping a switch.

thus mathematically if all 4 are pressurized at all times no less than 3, fully
pressurized in a specific direction can flip the switch (even if 2 are in one
direction that leaves 2 in the other.. so at best when 3 are pressurized, they
might be able to overcome the last one and leave it slightly off sync)
Ok... so it is untested...I need another Backhoe and another 6 dacta pneumatic
service packs to finish it...maybe when the taxes come in..

Yes, it probably walks faster than my synchronized walkers.

I use two switches per large piston.  One switch instruments when the piston is
closed, and the other when it is open.  The switches can be hooked in series to
know when all four legs have transitioned forward and back.

It never makes the next transition until all the pistons have completed their
travel.

I use two pistons per leg.  One for vertical and one for horizontal..... Almost
all the pistons are muscle pistons, but I need two switches (and pistons to
drive them) that provide the proper timing of the overall circuit.  Rather than
have a central timer that the muscle pistons mimic, the muscle pistons are the
timing pistons.

You can never have too much pneumatics.

Kevin








http://www.brickshelf.com/cgi-bin/gallery.cgi?i=551860


- Each leg is only connected to 2 pneumatic hoses

That is nice and tidy.

I wish... mine is gonna be hose city...

Mine too.  Two pistons, four switches, makes 12 hoses per leg.



- The feet swivel

Yes, I have a quadraped with swiveling feet and it makes a big difference on
traction.

Does it ever.. my quadruped high stepper (4" step height) can almost climb my
carpeted stairs with his u-jointed feet..

Interesting.. Ujoint lets it flex whatever way it wants?  No springs to try to
hold it in position.


<SNIP>

Comments:
This is a nice piece, but, personally, I'm not too fond of using the transmission to
shift the direction of leg movement, or for that matter, the whole worm->turntable
assembly.

Don't get me wrong, I'd love to see it walk, and it's better than any walker I've
ever made...  but then again, I've never made a walker...

Steve,

  I think you should give it a try.  Bipeds are the big challenge if you ask me.

Bipeds Rock! (Usually front to back or side to side).. seriously they are a fun
challenge...

I really enjoy them.  I've run dry on ideas for a while which is why I went to
quads.


  The octopod is an impressive piece of work.  You'll be happy to know that
bricklink orders are starting to arrive so I have enough red pieces to complete
all eight legs in red.  I've started to merge the RCXs, scout and radial
compressor into the body.


Huzzah!
Wow.. I'm trying to do it with the Mana IR units...I think yours will be more
impressive.

Its sure planned to have a *lot* of stuff.


  I'd like to avoid your standard rectangular body if possible.  They look so
unnatural.

I'm looking at something like an irregular Hexagon, or possibly Octagon for
mine...

Cool.  I could see that....Gotta see what we can do with 3-4-5 trianges.



  My leg design has lock, but it is using the folding table leg technique you
suggested.

Hm.. my legs have no lock...we'll have to see how it does...

We figure it weighs so much we have to have locks so that it can stand up
without pressure.


Kevin

Thanks for the inspiration Joe...

Kevin



Message has 2 Replies:
  Re: SSClagorpion - Another creature - Greene Scorp
 
(...) If you use a regular hexagon, the radial compressor would look awesome mounted on its side in the centre. ROSCO (19 years ago, 19-Jan-05, to lugnet.technic)
  Re: SSClagorpion - Another creature - Greene Scorp
 
(...) <snip> (...) Yeah, Im looing to isolate each movement completely and have it so the body doesn't have a grav well. I'm not 100% on the orderit may be that instead of AD going to AF, I do AD, -> BU -> AF -> BR -> BD -> AU -> BF -> AR -> AD (...) (19 years ago, 19-Jan-05, to lugnet.technic)

Message is in Reply To:
  Re: SSClagorpion - Another creature - Greene Scorp
 
In lugnet.technic, Kevin L. Clague wrote: <snip> (...) Almost as compact as my radial.. which I've developed /developing 3 and 6 cylinder versions as well.. the 3cyl radial is 12x13x4 studs and can easily be run with any motor (even the micro), but (...) (19 years ago, 19-Jan-05, to lugnet.technic)

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