The final standings from the
competition. We finished in third place.
The final points break down from the
competition.
The Rules for the competition. (Currently Unavailable)
Our Journal Paper for 1998.
The biggest problem when working on a water based vehicle as
opposed to a land based vehicle is that you can't just have it
run around the lab for testing.
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...T-minus one week
One week, oh my, only one week.
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...T-minus 3 days
Arrived at the hotel in Panama City, Florida. Hey, if this is a sub,
shouldn't it go into the water at some point?
We separated into two groups, the computer group consisting of
Tae Choi and Patrick O'Malley and the hardware group consisting of Scott
Nichols and Dave Novick. The computer group commenced setting up a local
network and then throughly tested the connection by playing some quake.
There were still a lot of things that needed to be finished before we
could put the sub into the water. The prop shrouds for one.
If Dave was unsure about country music before this day, any doubt was
removed after that day, since Scott would change the TV back to the
country music station every time Dave turned his back. Scott needed
background noise while working, and it was either that or MTV (sorry, rap TV is
an even worse solution).
(Mental note to self, bring radio next time to avoid bloodshed).
As it turned out, the noise from the dremmel motor tool, used to finish
the prop shrouds, drowned out most of the "music". And when that was
finished, the heat gun (used to thermally form the PVC) drowned it
out for the rest of the night till the bright early morning (that,
and dimmed the lights). About the only noise missing in this room was
an air powered wrench, like at a tire shop. We were not exactly model
neighbors that first night.
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...T-minus 2 days
The rest of the group arrived, and some room arrangments were changed.
The hardware team was now able to move to a room closer to the pool
(a plus when having to carry the sub there). And the rest of the
people fought it out amoung themselves.
Since we were going to try to use the camera to find the gates,
we needed to take some sample images to tune the centroid algorithm.
Most of the group headed out to the test pool with the camera enclosed
within it's waterproof container while the hardware team stayed behind
to finishes up a few last minute details.
We had decided that it would be good to be able to comunicate with the
processor without having to take it out of the tube. So we attached
another connector to the tube (which connected to the serial port of
the processor), and ran the wires out to a stalk attached to the tail
end of the sub which was well above the water line. This gave us
access to the processor without having to physically remove it. Now
we needed something to switch between modes, and reset it.
Magnetic switches were chosen to switch between download and run mode,
and to also reset the processor. The two different switches were set
apart far enough so that actuating one wouldn't actuate the other,
and everything was tested. After a few hic-ups, the hardware was
sorted out, and we could now download new code and reset the processor
without extracting it from the tube.
It was also an interesting day, since the competition started to
arrive. It was nice to be able to sit back and watch the other
teams preform the same sort of dance that we had done the day before.
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First on the scene was Johns Hopkins carrying a beasty of
a machine (with some really nice looking hardware). From the looks
of it, they could have used a couple of more members to help carry
it to the room.
They had two thrusters in the aft for forward motion and turning,
one tucked underneath for laterial motion, and one above, set at an
angle for depth control.
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Next was MIT.
They're configuration was similar to ours, a fore and aft
thruster for depth and pitch, and two on the port and starboard
for forward motion and yaw. The main difference between the two
was that ours had more similar dimensions from the nose to the tail
and the "wingspan" while MIT's had a more traditional submarine profile.
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Stevens wasn't able to book a room with the rest of us. So they
remained the "unknown" contender. They removed the guts of an R/C sub,
and decided to automate it, giving the body which most closely
resembles a traditional submarine.
For control, they used a single screw with a rudder for forward
movement and yaw, and a set of dive planes for depth and pitch
control.
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The camera party came back with less than good news. They were unable
to get any good images due to water conditions, so: (a) they wouldn't be
able to calibrate, and (b) it wouldn't matter since the camera
couldn't get any decent images anyway. No camera this competition.
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...T-minus 1 day- Static Judging
This was the first time that we were able to see everyone
together (well, the only ones we hadn't seen were Stevens
at that point). It would also be interesting to hear the
different strategies involved in completing the course.
Once the static judging was over, we quickly packed everything
up and headed back to the hotel pool.
At the end of the day, the sub was preforming some actions that
it shouldn't have been. It was determined that we may have blown
the 68HC11, so we pulled the sub and brought it back to the room.
Tae and Scott gently pulled the electronics from the tube, and
began replacing the chip. The motors were still twitchy, so the
motor drivers and the code were poured over to try to figure out and
solve the problem.
(Mental note to self, make the electronics easier to get to and
all within the same compartment
When the chip was replaced, the board was checked out to make sure it was
working along with the motors. They were, so the board was carefully
placed back into the tube. Again the motors were checked, and they were
working.
Time for a few hours a slee...zzzzzzzz.....
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...T-minus 4 hours
After a brief "sleep" (~1.5 hours), we still had a "few" things still
to take care of:
(1) Getting the sub to submerge
(2) moving in a straight line.
Nothing big.
While we checked the motors the "night" before, we didn't check the
rest of the electronics. When we tried to travel in a straight line,
the sub wouldn't go. It seems at though we had lost communication with
the compass. This was a bit of a problem, since we needed that to maintain
a heading.
We checked over everything that we thought would be the problem, but
we couldn't seem to ferret it out. With a deadline approaching, we
decided to move on. We could charaterize the motors to get the sub
to track in a straight line.
side note: After looking at it later, it turns out that the send and
receive lines were crossed.
(Mental note to self, ALL cables must be keyed)
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...T-minus 1 hour
We still haven't gotten the code in place for the submarine to submerge,
so we decided to work on that. This was an important part in turning
our "boat" into a "submarine".
To submerge, the sub had to open the air valve and drive downward with
the motors. This would fill the buoyancy compensator with water. There
was no control on the air valve, once it was open, it would slowly bleed
air out until it closed once again. After some trial-and-error from
Tae's code, we were able to get the sub to be almost neutrally buoyant.
Now to tune the motors to track straight. The sub would arc slightly to
the right, so again we started out with trial-and-error to remove it.
The first attempt didn't improve things much. In the second attempt,
the parameters were adjusted more drastically...
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...T-minus 10 minutes
At that point, Scott and then Dave realized what was going on with the
motors. Since the kill switch was an FM R/C receiver it would "twitch"
when it didn't receive a strong signal. So when the sub was underwater at
Panama City, the signal was lost, the servo kill switch would twitch, and
cause the motors to be turned on and off (this did bad things to the
motor drivers, and Tae writing the software to drive the sub).
This didn't happen back in our lab, probably because Panama City was just
more RF noisy than Gainesville.
(Mental note to self, no more mechanincal kill swtiches attached directly
to an R/C servo).
Once we realized that, Dave and the sub were loaded into the back of
the van and Dave set about trying to make the kill switch less sensitive.
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...T-minus 0 seconds - Competition Time!
The sub and Dave (still working feverishly) are placed on the cart and
both are rolled unto the staging area. The clock is ticking, but we
have ten minutes until the sub can hit the water and about an hour of
work to do. Hmmmm....
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...T-plus 10 minutes - 20 minutes of competition time left
Our 10 minute "on dock" time was up but we were still trying to
finishes with the new, and hopefully better, kill switch.
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...T-plus 20 minutes - 10 minutes of competition time left
Finally got the kill switch in place, and we're ready to put it
into the water. Even with the "new and improved" kill switch
the twitchy servo was causing all sorts of havoc with our motors
and processors.
We explained our problems to the judges, and asked if we could
totally disable our kill switch. With a "yes" from the judges,
we pulled the sub out of the water, and ferverishly yanked the
electronics out of the tube, and secured the kill switch to the
on position.
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...T-plus 25 minutes - 5 minutes of competition time left
With the "new and even more improved" non-kill switch in place,
the sub is again lowered into the pond. It's reset and let go
(with Tae saying a little prayer for good luck).
The sub started up, activated the air valve and filled the
buoyancy compensator. Once neutrally buoyant, the sub dove
to the preprogrammed depth, and proceeded on a heading.
However, since we were unable to fully characterize the motors,
the submarine did a fairly bad impression of a pool scrubber by
taking a fairly tight turn to the left, and getting hung on
the edge of the platform, where it scraped along to the
right.
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...T-plus 27 minutes - 3 minutes of competition time left
Since this wasn't an impressive run, Scott asked if he could
grab the sub to reterive and reset it, and not have to wait for the
divers (since it was right there at the launching pad).
When they said yes, team members grabbed his legs, and he went went
head first after the sub. Unable to grab it, he wiggled down to his
ankles and snatched the sub.
While this was happening, the divers heard a splash and ran to see
what had happened. From the looks of it, they though we were putting
Scott through a "water test", either he made the sub work, or we'll
drown him (not really a bad assumption), and they dove in to save him.
Because of his dedication to the project, and lack of fear of bodily harm
(or just shear stupidity), the divers awarded him an honorary
Naval Experimantal Divers Unit (NEDU) divers shirt.
side note: Because of Scott, there was a new rule put in place that
no team member can enter the water to reterive an errant sub.
With the sub reset and repositioned, this was our last shot at a
straight run. Alas, it didn't happen. Once again, it took a fairly
sharp left-hand turn, got hung up on the wall, and scrapped it way
to the right (not that, by this time, it was a big suprise). With
the loss of the compass, we couldn't maintain a straight heading.
The run was preprogrammed to dive, turn the motors on for a certain
length of time, and then surface. We were in the middle of the run
when the competition time ran out. After about another minute,
the submarine finished it's run, and surfaced.
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