By Angelica Lim
Underwater robotics on the French Riviera is pretty glamorous. I mean, here I am, treading water in a rich neighbor’s garden swimming pool, holding up the end of a bobbing aluminum tube so it can get wifi access. (Who knew 802.11g didn’t work underwater?) “Next year, we’re getting a waterproof Ethernet cable for this thing,” I sputter in French as my Level 1 swimming lessons fail me.
It’s sunny, but that doesn’t help Franck see his laptop any better. “Bon, ça y est,” he calls out finally. Thankfully, I let go of the 26 kilo metal beast, and it floats lightly, just under the surface of the water. I scramble out of the pool and observe. And 10 seconds later, as planned, our baby AUV – autonomous underwater vehicle – begins its descent.
(Photo credit: Angelica Lim)
But of course, this test, performed just 4 weeks ago, was only the culmination of over 6 months of work involving a team of 12 researchers and students, and lots and lots of sponsorship money. The payoff this project is big though – for one thing, Têtard (the name of our robot, meaning Tadpole) could grow up to be big shot industrial AUV one day. (Sometimes I imagine it zooming around at 2m/s in the frigid waters of the Atlantic, searching for mines to neutralize… with racing stripes…)
More likely, though, Têtard will go head-to-head against other AUVs at the international SAUC-E competition. No, nothing about whipping up the best spaghetti sauce (don’t even try Googling it), SAUC-E is the clever acronym for Student Autonomous Underwater Challenge – Europe. And my team from l’Université de Nice was going to win it.
Zip ahead to July 10, 2007. The rendez-vous point is Gosport, England.
(Photo credit: Louis-Kenzo Cahier)
Being a most obviously-organized-by-the-Ministry-of-Defense competition, my team and I are housed up in gender-separated “military-style accommodations”, which include plastic mattresses and a rotten plum in the trash bin upon arrival.
I won’t even get into the Mess Hall food, but admittedly, I didn’t have as hard a time as the my French teammates, who gaped on incredulously as I gulped down what they called “une espèce de flageolet dans une sauce… berk” (a kind of saucy bean thing… yuck). Baked beans at breakfast. That’s not too bad, non?
(Photo credit: Louis-Kenzo Cahier)
Anyway, once everyone was filled up with their daily default bowls of cereal, off we went to the competition site. Now, I’m not sure if you’ve ever seen what I’m about to describe, or will ever see in your lifetime. See, in the heart of Haslar Military Base, tucked away in an indescript brick 2-story building, is the most enormous indoor body of water I’ve ever seen. Imagine a football field. No -BIGGER. 122m x 61m, to be exact. That was how much 5m-deep water is located in the Qinetiq Ocean Basin Tank, big enough for underwater submarines to perform maneuvers in.
(Photo credit: Fabien Valoit)
And all that water was what our AUVs were up against. See, water-tightness doesn’t just mean sticking it into the bathtub for a few minutes and hoping the seals hold. This is heavy duty, 20-40 min. underwater autonomous missions, in pressures that crush soda cans. And when onboard electronics costs can skyrocket into the thousands, they must NOT get wet. Luckily, our little Têtard, unlike pretty much all the other teams’ robots, had not a single water-tightness problem :)
However, actually performing the missions required of us was the bigger challenge. Our subs were asked to maneuver an underwater validation gate, differentiate between two buoys and hit the orange one, drop a marker on a big X target on the pool floor, recognize a couple other objects, and more — all while in “no-hands, ma!” autonomous mode.
(Photo credit: Fabien Valoit)
But here were, having problems getting our motors going.
See, as a computer scientist, I love the theory behind the control strategy, image recognition, localization and all that wonderful jazz– that’s what we spent the last half a year working on. But the thing is, when your robot’s hardware is broke, it’s game over. Without the robot, code is just code.
And, frustratingly, on the day of the final round, our motor board just… died.
Our system of aluminum, circuit boards, sensors, sonar, webcams and thousands of lines of C++ code was reduced to a useless hunk of motionless metal and plastic, imbibed with love, sweat and gooey pizza all-nighters. We explained to the crowd that they would not be seeing Têtard in the water that day, the same robot that easily passed the in-water qualification the day before.
A couple hours later, I watched helplessly as Nessie II, the promising AUV from Scotland, was reduced to the same hardware-defeated motionless state, and I realized this really was an unforgiving field. Lesson learned: buy well-tested, off-the-shelf products, and then you can go crazy coding!
I learned my lesson so well that this October, I’ve got a team prepping for the Richard Tapia Robotics competition where the hardware, a souped-up iRobot Create, will be supplied for us. Ah, after all this AUV stuff, this terrestrial robot will be a breath of fresh air. Can’t wait!
Although, maybe one day I’ll head back into Underwater Robotics…
…you just can’t beat the sun and swimming pools ;)
(Photo credit: Louis-Kenzo CAHIER)
Angelica Lim is an undergraduate in her final year of studies in Computer Science, at Simon Fraser University, BC, Canada.