To LUGNET HomepageTo LUGNET News HomepageTo LUGNET Guide Homepage
 Help on Searching
 
Post new message to lugnet.roboticsOpen lugnet.robotics in your NNTP NewsreaderTo LUGNET News Traffic PageSign In (Members)
 Robotics / 23287
Subject: 
Re: TGBC - The Weakest Link?
Newsgroups: 
lugnet.robotics
Date: 
Sun, 9 Jan 2005 23:34:04 GMT
Viewed: 
5472 times
  
In lugnet.robotics, Mark Bellis wrote:
A module with 2 input faces would probably be a hopper with 2 chutes entering
it.  The greatest problem I've had with ball contraptions is balls clogging in
the hopper - sometimes you need an agitator like they use in factories.

Any operation involving a long sequence of events as in The Great Ball
Contraption (TGBC) is likely to be fouled up by failure of one of the events in
the chain - the so called weakest link.

Is there allowance for the fact that one of the modules may act up and not
deliver the requisite balls for the next module to act on?

Each module must at minimum be able to sense that there are indeed balls in the
input bin before acting on them and that there are balls in the output bin for
the next module to do its stuff.

A fail-safe mechanism would be such that the offending module can be by-passed
so that the sequence can still go on. I envisage Steve's train could be just the
thing to do the job, running hither and thither to make sure the whole
contraption is working.

But to complicate matters, the weakest link may not be just one module.
Different modules could act up at various times.

CS


Subject: 
Re: TGBC - The Weakest Link?
Newsgroups: 
lugnet.robotics
Date: 
Mon, 10 Jan 2005 02:46:59 GMT
Viewed: 
5487 times
  
In lugnet.robotics, Chio Siong Soh wrote:

Is there allowance for the fact that one of
the modules may act up and not deliver the
requisite balls for the next module to act
on?

   First, test the modules as they are added to the system to make sure they
meet the minimum requirement. Second, watch the whole thing like a hawk, being
ready to shut it down to fix such problems. Third, there will have to be some
special-purpose modules within the system, such as the first "timing module", a
"return module" (like Steve's train), perhaps turn modules, etc. A very simple
bypass module can be built (I'm working in it) that can easily be adjusted in
length "on the fly" so a malfunctioning module can be hot-swapped out of the
line.

Each module must at minimum be able to sense
that there are indeed balls in the input bin
before acting on them and that there are balls
in the output bin for the next module to do
its stuff.

   At this point, most if not all of the modules I've seen can "run dry", so
there's not need for a module to check for itself.

But to complicate matters, the weakest link
may not be just one module. Different modules
could act up at various times.

   Yes. Babysitting will be needed.

--
Brian Davis


Subject: 
Re: TGBC - The Weakest Link?
Newsgroups: 
lugnet.robotics
Date: 
Mon, 10 Jan 2005 02:55:50 GMT
Viewed: 
5465 times
  
In lugnet.robotics, Mark Bellis wrote:
A module with 2 input faces would probably be a hopper with 2 chutes entering
it.  The greatest problem I've had with ball contraptions is balls clogging in
the hopper - sometimes you need an agitator like they use in factories.

Any operation involving a long sequence of events as in The Great Ball
Contraption (TGBC) is likely to be fouled up by failure of one of the events in
the chain - the so called weakest link.

Is there allowance for the fact that one of the modules may act up and not
deliver the requisite balls for the next module to act on?

Not really.  :)

However, we're not expecting the GBC to run 100% of the time.  It's not like letting
a train run in a circle for eight hours.  There are all kinds of things going on at
the same time.  In our testing, we seemed to run for about 20 minutes at a time,
before someone would say, "Stop..."

Then, we'd shut down the contraption, pick-up loose balls, check weak spots, and
power it up, again.

Generally, if one module doesn't work, we'll just take it out, slide the other
modules together, and start going again.  Given that there are no "special" modules
(beyond the first and last modules) any other module can be placed in any location.

Each module must at minimum be able to sense that there are indeed balls in the
input bin before acting on them and that there are balls in the output bin for
the next module to do its stuff.

I'd kind of like to see a module that won't "work" if it's empty.  :)


©2005 LUGNET. All rights reserved. - hosted by steinbruch.info GbR