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 Robotics / RCX / legOS / 1066
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Subject: 
Re: Very strange problems
Newsgroups: 
lugnet.robotics.rcx.legos
Date: 
Sun, 21 May 2000 18:03:14 GMT
Viewed: 
1390 times
  
On Sun, 21 May 2000, Tobias Bende wrote:

Date: Sun, 21 May 2000 19:46:40 +0200 (MET DST)
From: Tobias Bende <f96tobe@dd.chalmers.se>
To: Luis Villa <liv@duke.edu>
Cc: lugnet.robotics.rcx.legos@lugnet.com
Subject: Re: Very strange problems

It seems that emulegos should be able to handle IR. However, it does not
use the lnp-functions that I use, so I presume it is designed to work with
an earlier version of legOS.

IIRC, it is 0.1.7, which used a completely different setup for the IR
communication.

I was afraid so.

Argh. I was getting emulegos (which I was pretty familiar with) and
legosim (which I though was C, not Java) confused. I'm afraid neither of
them would be too easy to port to 0.2.x :(

Were earlier versions of legOS (I use version 0.2.3) less likely to cause
the RCX to lock up?

Unfortunately, no.

Another question for Luis. You said that you had to change in your
programs so they didn't hang the RCX. Did you ever experience that a
program that didn't hang the RCX the first couple of runs, later started
doing this?

You mean, unmodified? No, I don't think. I've seen lots of code that
worked, and then got "simplified" and then stopped working, but I don't
think I've seen unmodified code that suddenly stopped working. Is this
the GA code? Or something else?

We haven't reached the GA part yet. Right now the idea is to work out a
communication protocol and then send a information back and fourth.

Please make sure to share this with us! IR continues to be legOS's
weakest point, and once someone works out a reliable way to do this,
it'll be extremely useful for many people.

And
since the RCXs locked up we thought that there must be something wrong in
the programming.

Unfortunately, no (though if you are multi-threading, there may be some
issues there...)

It seems we just have to deal with the fact that legOS is strange and try
to get it to work anyway. I just wondered if we could be resonable sure
that a program that worked didn't just stop working. That wouldn't be good
after several hours of training the GA population :).

Yes. We seriously considered doing GA stuff, but this was a concern. I'd
suggest working out a backup protocol, by which the values of your genes
(what is the technical term for that, anyway? I forget.) are regularly
transferred to the PC. That would give you something to fall back on if
there is a problem.

BTW, the neural net code is very slow, since it requires floating point
emulation.

We figure our GA system will also be pretty slow due to the fact that the
individuals need to be tested by actually moving the robot. Depending on
how fast we can transmit data over IR, this might be a time factor also.

Oof. That will be painfully slow, I'm afraid. What problem are you trying
to solve, exactly? I'm very curious, now :)

Luis

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           "Going to California with an aching in my heart.
               Someone told me there's a girl out there
            with love in her eyes and flowers in her hair."
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Message has 1 Reply:
  Re: Very strange problems
 
(...) We have not done anything to ensure that whatever is transmitted is received correctly (i.e. without errors). What we have done is a build a system which will work even if one (or several) of the RCXs are temporarily blocked for some reason. (...) (25 years ago, 21-May-00, to lugnet.robotics.rcx.legos)

Message is in Reply To:
  Re: Very strange problems
 
(...) I was afraid so. (...) We haven't reached the GA part yet. Right now the idea is to work out a communication protocol and then send a information back and fourth. And since the RCXs locked up we thought that there must be something wrong in (...) (25 years ago, 21-May-00, to lugnet.robotics.rcx.legos)

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