Mobot competition draws on student's creativity
Mobot, one of the least celebrated but most impressive events of Carnival, is a competition that pits teams and individuals in an attempt to build a robot that can navigate the slalom course on the sidewalk in front of Wean Hall. The competition ranking is based both on the number of "gates" the robot successfully passes through, and how fast it can pass through them.
The Mobot course, itself a landmark on campus, is a treacherous route for the mechanized competitors that traverse it every year. Starting near the side entrance to Doherty Hall, the course goes down two inclines and across rough, uneven concrete, twisting and turning before hitting the largest challenge in the final leg: the decision points. Here, the path diverges and the robot is given two choices as to which path to follow. One path remains straight; the other leads around a curve to the next gate. If a robot chooses the straight path, it cannot progress any further in the race, because it will not go through the rest of the gates sequentially — a requirement to win. There are five decision points in the last portion of the race, but many robots don't even get this far.
Electricity was in the air, or at least in the robots, on Friday as the sun crested the top of its daily trek. Tables were set up behind the race course for teams to make final adjustments to their robots as noon, and the race deadline rapidly approached. Crowds thickened faster and faster as people enjoying the weather came to see why there was all of this fussing. The first of two competition heats started at noon; six robots competed in each heat. There are two classes of robots — the open class and the undergraduate class. Robots in the open class are not eligible for as much prize money, but they don?t have to be built by undergraduate students. This year, there were four robots in the undergraduate class and two in the open class.
The first robot to race, Fbomber, seemed to struggle under its own weight as it progressed toward gate 1. The robot appeared to be made mostly of clear plastic or fiberglass, but its distinguishing feature was a small laptop strapped to the top, which served as its processing core. Unfortunately, the extra processing power that the laptop may have afforded Fbomber became a burden — the robot stalled halfway to gate 1 in both heats, getting caught on a crack in the concrete in the second heat.
Milo, and then Cornflake, followed Fbomber. Milo and Cornflake used similar designs ? they mounted a camera to the front of a pre-made remote-controlled car. The advantage of this approach was that the teams could spend all their effort on the navigation portion of the robot, instead of figuring out a strong design. Another advantage was that the robots were fast. Milo proved to be too fast for its own good and spun out after gaining speed down the first ramp in the first heat, veering off the course into the grass almost immediately after starting in the second heat.
Cornflake fared much better. In the first heat, it blasted down the course and made it to gate nine before choosing the wrong path at the first decision point. The second heat saw Cornflake correctly following the first and second decision points, making it all the way through gate 11 before missing a turn. With a time of 1:16.97, Cornflake won the first-place undergraduate prize. Jack Wu, a junior in computer science, was on the Cornflake team. "Last year we had something that worked as well, but we spent too much time with the speed control ... and we didn't have enough time for the end, the decision points," Wu said. Team Cornflake learned from its mistakes, and came out on top this year.
While Cornflake was a tough act to follow, the final robot in the undergraduate class to compete was an unlikely competitor. Designed and built by first-year mechanical engineering student Dave Urban, Fubar Junior wended carefully along the course, clad in pieces of a black garbage bag, a beer logo printed on office paper, and the insignia of Urban's fraternity, Sigma Nu. Fubar Junior had a rough start, getting caught on the crack in the sidewalk before gate 1. However, the robot showed its worth in the second heat, using a slow-but-steady approach to make it through gate five in 3:35.30. Its time garnered the second place award in the undergraduate class. "Every 20 tries or so it would get caught in that crack, and I was hoping it wouldn?t be on race day, but it happened on the first try. I was very concerned," Urban said. "As soon as I came here visiting as a freshman, I was like 'I'm gonna do this.' And here I am."
There were only two robots in the open class, Dodgy II and Pikachu. Dodgy II used speed to its advantage, making it through gate five in just a fraction over 24 seconds. Dodgy II was one of the most visible robots at the competition, with a large green circuitboard sticking out of the top. Its creator sat on the course between heats with his laptop making last-minute programming changes. Pikachu, the other robot in the open class, won the Judges' Choice award, using a large front-mounted fan to clear debris off the course, and made it through gate 3 in both heats.
Some of the best sights were during the exhibition heats, though. Dan Bothell, a Carnegie Mellon alumnus and staff member and the winner of the first Mobot competition 11 years ago, presented two robots for the exhibition heat — his original winning robot from the first competition, now dubbed DJB XI, and a new creation, DJB Xla. His new robot used a very unique design: a "blind" robot which used a walking cane and feelers to find itself to each gate. "The new one was just an idea.... It was just to try something different, just to have some fun," said Bothell. The other exhibition robot was Team Biped, which actually built a pair of legs that traversed the course extremely slowly. It walked off the course after a few feet, but the robot's balance and weight shifting elicited gasps of amazement from the crowd.
Hopefully the Mobot competition will gain more attention in the coming years. The computer science department-sponsored event is a fantastic way for Carnegie Mellon students to show off their talents in the exploding field of robotics, and it is just one more of those little quirks that gives Carnegie Mellon a healthy dose of personality. After all, what other university sees fraternities cheering their brothers' robots on?