Day 3 (July 18th 2012) #2

Posted by admin-robotlord on July 18, 2012

Wow! It’s been a whirlwind three days…so much time, and yet it seems, so little has been done…but we’re getting there, slowly.

To recap: Monday was the start of our epic journey. The five of us met up at YEG (that’s Edmonton International Airport for those who don’t know) bright and early to make our 8:30am flight to Calgary. Once in Calgary, we had barely an hour to retreive our luggage, go through customs and then security, and make our connecting flight. Suffice it to say, we made it, with only minutes to spare. We did have some concerns about the security agents confiscating our lithium-polymer batteries that myself and Lee were carrying, but once we explained what they were for, they waved us on with nary a cavity search.

We arrived in San Diego (which, as it turns out, is a bit colder than Edmonton has been the last couple weeks – a balmy 20C, compared to our 30C…) with a comfortable hour margin to get our luggage and pick up our rental van. After I spent another half-hour in line, I recieved the keys to our shiny new Kia minivan. I was the proud recipient of a wasp sting while loading the van, which was an unpleasant welcome, to say the least, but there was no time to cry about it…we had to check in to our hotel, find our shipping crate, and attend orientation, all in a few short hours.

Since I had (ahem) ‘mis-placed’ the tracking number for our crate, it took six (yes, six) calls to FedEx before someone competent enough was able to find the tracking number for us. Once we had that in hand, we had to rush downstairs to attend the orientation meeting, and once that was over, rush to find our crate before nightfall.

After some attempts to get help from the desk clerk, with little success, we decided the best thing to do was go to the other tower (there is 2) to see if they had our crate. After some discussion with the head bellhop and a very helpful security guard, we found our crate, nestled amongst other deliveries in the back of the hotel. With much relief, we unloaded everything into our van and trucked it all to our hotel room for safe keeping. Once that was done, it was off into town to pick up some supplies (snacks, water, sunscreen…), some late-night supper (DelTaco) and finally, back to the hotel to reassemble SubmURSA. If that day wasn’t exciting enough, well, it was about to get even better.

Upon our return, we wasted no time in turning me and Veselin’s room into an electronics lab. While testing one of our new motor-controller designs, somehow one of the H-bridge ICs decided to end it all and fail in a spectacular fashion. Then, not too long after, a wiring mishap resulted in yet another spectacular failure of one of our spare compasses. At this point, it was agreed that we should call it a night, as our brains were fried, and we wanted to avoid more of our equipment meeting the same fate.

The next day, we arrived at the TRANSDEC with an eye towards making some headway to getting SubmURSA in the water. It was a day frought with dissapointment. First, the motor controllers refused to behave as designed, in spite of their prototype versions working properly in the lab. Then, various elements on the main board began to behave oddly. The depth sensor was not working, but that was chalked up to a programming error and quickly resolved. Then, a power board failure destroyed one of our NetBurner modules. Fortunately, we had the foresight to not use the NetBurners we were planning on using in the platform, so we avoided damaging one of them. At this point, things were looking bleak for our electrical systems. We needed a reliable solution for power, motor control, and interfacing, and we had none of it. I spent the better part of the day puzzling over our problems with Lee, while Scott diligently worked at static balancing and adjusting SubmURSA.

Since Scott needed some equipment to assist in SubmURSA’s buoyancy problems, him and I ran to Home Depot, and I welcomed the much needed break. On our way back, we agreed we needed to take part of the evening and relax, as tensions were high, and spirts were low.

So, upon our return to the hotel that evening, we all turned in early, with an eye towards getting up and starting fresh in the morning.

So Wednesday: Again, the same problems, but a new day. After some discussion between Lee, Veselin and I, we agreed that somehow the directional control logic was causing unpredictable problems, and we could simply bypass it entirely, using the spare eTPU channels on the NetBurner. I rigged up one of the motor controllers to do this, so we could get some testing on SubmURSA’s ability to maintain a heading. After excising some gremelins from the main board, Lee and I turned our attention to our power problems. The 3.3v regulator was getting far too hot, and was dealing with a larger load than expected. We attempted various solutions using available hardware, and even borrowed components from Montana State to construct a switch-mode supply. At this point, I realized that we had a pico-ATX supply for our spare embedded computer, and that would easily supply the needed 3.3v, although Veselin wasn’t sure if it worked properly, as there were problems with it in the past. Seeing as we had nothing to lose, I rigged up the pico-ATX to our Vicor regulator, and behold – POWER! We now had a reliable source!

We quickly mounted our electronics in the hull, and began testing in the dolphin pool. Things were looking promising. We were able to read a heading, and the problems we had back home with erratic communications loss between the NetBurner and compass were now gone. By this time, though, it was time to pack up and head home for the evening. We went back to the hotel, ordered some pizza, and got ready for some testing in the hotel pool after supper.

Veselin, Charles and I headed down to the pool after supper, while Lee stayed behind to assemble the sonar board, and Scott wanted to assemble a bump sensor (to detect a buoy strike). Initial tests look promising, but the compass readings began to deviate as we travelled across the pool. One of our friends from Reykjavik informed us that one side of the pool caused anomalous readings when they went over it with a compass. This made sense, as SubmURSA always deviated at the same spot. We did some more testing at maintaining a heading, but suddenly the compass simply froze. At this point, we ended the night’s pool test and headed back to the room to check readings with our spare compass. That checked out fine, and when we reconnected the other compass, it suddenly began to work fine. Strange, but not atypical for SubmURSA, we decided to call it a night and do more testing tomorrow, as well as prepare for our static presentation. To the gate!!


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