Re: Speed

[Tim Vanderhoek <vanderh@ecf.utoronto.ca>]

On Sun, Nov 21, 1999 at 10:24:41PM -0500, Joyce Poon wrote:
> 
> tagged (due to the transmit tag rule).  I don't know whether pushing an
> obstacle around makes the obstable part of our robot (ie does the
> obstacle become a "dangling object?").

That's a good question.  I'd be of the opinion that "It's not our
fault if Malone didn't bother mooring his obstacles properly".


> d) What happens if we break an obstacle... we might get disqualified...
> That could be funny actually.

The idea occurred to me when I wondered what would happen if Malone
put mirrors in the playing field and our robot picked-up a reflected
signal off a mirror and decided to head at high speed towards the
mirror...   :-)  Isn't breaking a mirror supposed to be bad luck?  ;-)


> e) pushing around stuff will slow the robot down.

Well, what I envisioned was: our robot is cruising around going at
high speed (what other speed is there? :).  Since our current design
calls for significant amounts of metal, it's probably not the
lightest thing around.  We've got a fair amount of inertia.  All
of a sudden, *BOOM*.  The mechanical side-sensors get triggered,
the computer realizes we've hit an obstacle.  However, hopefully
we'll also figure-out some kind of feedback mechanism to let the
computer know what our real-life speed is.  The computer checks
this feedback and says: "Hey, my mechanical side-sensors are getting
triggered, but we're still moving...  Hmm...  Let's just keep on
moving and ignore the side sensors!".  At this point the computer
could also do a check....if the side sensors stay triggered (ie.
we're actually pushing the obstacle instead of just knocking the
obstacle out of our path (as would happen for eg. an upturned
garbage can)), and if the speed feedback mechanism reports that
our speed has been reduced, then pretend we ran into a hard,
non-moveable obstacle.  This would handle part i of point e).

Part ii of e) is that constantly pushing stuff around would probably
impede our sensor range.  I don't see this as being a real-life
practical problem; rather a theoretical problem that can't actually
occur with any likelihood.

The theoretical converse to part ii of e) is that constantly pushing
an obstacle around is an interesting (but probably not terribly
effective) way of hide being this obstacle when in evade mode...


> f) motor may require more torque.  (there could be more work involved with
> speed control & sensors as well -- ie when you want to go 3ft/s while

Hmm...  Adding extra motor power simply on the expectation that we'll
need it to push an obstacle...  Interesting idea...  I should've
thought of it.  :-)


> g) how can we distinguish between the outside barrier (ie the ring around
> the playing area) and an obstacle inside the playing area?

Presumably the playing area will not move.  The boundaries forming the
playing area are probably supported by people who would not permit the
boundaries to displace them.


> Pushing around the barriers will confuse enemy robots (esp the
> teleoperated ones) <HUGE ADVANTAGE>.  However, we have to somehow keep
> track of where the barriers are too, so we don't get confused.

Hmm....


Of course, it's quite possible that this is all bullshit.  It may well
be that Malone is smart enough to moor all of the obstacles, or that
he realizes what our plan is and adds some stupid rule to thwart us.
We must not ask Malone about such a strategy directly...  :)  Should
it be useful on competition-day, it would merely be an "Oops....How'd
that happen" type of accident, of course...  :)

Nonetheless, a 10kg robot travelling at 1m/s possesses quite a lot of
inertia (10kgm/s, to be exact :).  Having a large weight does not
necessarily need to be a disadvantage (as we earlier assumed)...
Going all the way to 10kg would require bigger more expensive
batteries, bigger more expensive motors, but other than that, the
disadvantages we considered earlier were mostly imaginary.  There's
no reason that strong motors wouldn't be able to stop and start
even a 10kg robot quickly.

A 10kg robot will tend to naturally be more robust.  :) :)

Our selection of motors is, of course, somewhat limited by what
happens to be available during that week at good 'ole Active
Surplus...

It's definately an interesting idea...  It's one of those things
that would clearly differentiate our robot from everyone else's,
since undoubtebly everyone else will be trying to make their robot
as light as possible.  That fact alone is enough to interest
me, since capitalizing on one or two different/innovative ideas is
often a good way to win competitions.

I'm as yet unconvinced either way...

[ Hmm.. ]


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