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Subject: 
Re: SSClagorpion
Newsgroups: 
lugnet.technic
Date: 
Wed, 14 Apr 2004 19:59:21 GMT
Viewed: 
11607 times
  
In lugnet.technic, Steve Hassenplug wrote:
> In lugnet.technic, Kevin L. Clague wrote:
> > In lugnet.technic, Steve Hassenplug wrote:
> > > In lugnet.technic, Kevin L. Clague wrote:
> > > > This will be interesting because it is my first partner build.....
> > > 
> > > >   1.  Typically they walk forward with two groups of four legs.
> > > >   2.  Turning is done by using a different sweep, primarily with the front two
> > > > and back two legs.
> > 
> >   With four polarity reversors (16 pneumo switches), we can make it walk
> > forward, backward, turn right or left.  If we used more polarity reversors we
> > could make one side walk forward, while the other side turns, leading to a
> > curved walking path.
> > 
> > > ...
> > > > Two groups of four legs is a simple extension to hex242 and hex363.
> > > 
> > > 
> > > Will this type of design allow it to turn in place, or can it only turn while
> > > walking forward/backward?
> > 
> > All of the above.
> > 
> > > 
> > > I think it should be able to turn in place.  That could mean dis-connecting the
> > > legs on each side.
> > 
> > Nope, just dilligent reversal of horizontal leg sweep.
> > 
> > > 
> > > Also, moving sideways would be cool.  That would mean adding a side-to-side
> > > piston, to go along with the forward/back piston on each leg.  Right?
> > 
> > Yes, I think this would take a third degree of freedom in the legs.
> > 
> > > 
> > > Thoughts?
> > 
> > Plenty of them.
> > 
> > > > 
> > > > The walking mechanism will be completely wired into pneumatics.  For walking
> > > > backwards, we can use pneumatic polarity reversors controlled by RCX/Motors.
> > > > The RCX may need to know that we are in the right state before it changes the
> > > > muxes, so that will take some kind of sensor.
> > > 
> > > 
> > > The control could be Motor->pneumatic switch for:
> > > C) Forward/Backward, Stop/Go, Same/Opposide (legs on both sides go same
> > > direction or opposite direction)
> > 
> > 
> > We have to use polarity reversors in pairs.  If we reverse the leg sweep, by
> > swapping pressure hoses, then we need to swap the AND gate outputs (two
> > pneumatic switches) also.
> > 
> > For walking backward, we reverse *all* the leg sweeps, and reverse the output of
> > the sweep complete AND chains.  This requires one motor to flip these two
> > reversors.
> > 
> > For turning, we reverse *half* the leg sweeps, and reverse the AND gate outputs
> > for the same pistons.  We can hose things together so we can use only one
> > reversor for this.  So turning requires one motor to flip these two reversors.
> > 
> > Since you want to stop, you probably want to use a motor and a single pneumo
> > switch to the *off* position.
> 
> 
> 
> Ok, so I'm thinking about motors to flip pneumo-switches.  Each of these may be
> one or more switches, all activated at the same time.
> 
> 1) Switch for Start/Stop (on/off)  When this switch is "on" the scorpion will be
> walking. (legs going up/down + some other direction).  This switch will activate
> all eight legs.

Yes.

> 
> 2) Switch to select forward or backward for left legs.

No.

> 
> 3) Switch to select forward or backward for right legs.

No

> 
> 4) Switch to select forward/backward OR side-to-side for left legs.
> 
> 5) Same as 4 for the right legs.
> 
> 4&5 are optional, depending on if it CAN go sideways.

No.

Ignoring side walking for a moment.....

  1) One motor to turn a single switch on/off.  This allows or prevents walking.

  2)  One motor to flip 8 switches.  This one controls walking vs. turning.

  3)  One motor to flip 8 switches.  When walking, this one controls forward vs.
backwards.  When tuning (in place), this one controls right vs. left turning.

I see no reason to turn off one side or the other, when we already have a
mechanism that will turn in place.

If we wanted to get fancier, we could add two more sets of controls so that one
set of four legs can walk forward/backard or turn right/left, while the other
set of legs can walk forward/backward or turn right/left.

With seperate leg group controls we could have it walk in a curved path by
having one leg group (four legs) turning, while the other leg group is walking.

You might want to study this:

http://www.kclague.net/Quad242/index.htm

In particular the movies of walking/turning to see what I have in mind.

Kevin



Message has 1 Reply:
  Re: SSClagorpion
 
(...) That was my second choice. Ok, three motors. If it can be worked out, we COULD combine #1 and #3, right? Leaving: 1) Function (walk/turn) 2) Direction (forward/backward/stop) I assume both of these groups are controlled only by motors, and at (...) (22 years ago, 14-Apr-04, to lugnet.technic)

Message is in Reply To:
  Re: SSClagorpion
 
(...) Ok, so I'm thinking about motors to flip pneumo-switches. Each of these may be one or more switches, all activated at the same time. 1) Switch for Start/Stop (on/off) When this switch is "on" the scorpion will be walking. (legs going up/down + (...) (22 years ago, 14-Apr-04, to lugnet.technic)

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