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  • Tank Wars 1
    Credit: Caltech
03/13/2018 15:24:36

In Grueling Combat, The Riveters Emerge Victorious

This year's ME 72 design competition consisted of a round-robin of five rounds, then sudden-death elimination playoffs leading to the final round. The top two teams from the round-robin earned a bye during the quarterfinal round of the playoffs, advancing directly to the semifinals.

There were six teams: The Riveters, DA$ ROBOB0BOZ, Guardians of Spalding, Ring of Fire, Toast, and Team Floyd. Two teams took the field per match, each seeking to occupy the three bases: one atop a hill, one on a seesaw, and one on the ground at the center of the field. For every second that a team held a base, they were awarded varying points: 1.75 point for the hill, 1.375 points for the seesaw, and 1 point for the center base.

Here's a play-by-play of the action:

Round 1:

The Riveters vs DA$ ROBOB0BOZ: The Riveters deployed what would become their signature strategy, parking one robot at the apex of the seesaw, turning it into an elevated plank that was unassailable by their opponents. Score: 504 to 193, The Riveters

Guardians of Spalding vs Ring of Fire: With each team fielding only two robots, Guardians split their forces and claimed the hill and the seesaw. Ring of Fire attempted to double-team the robot on the hill, but were pushed back by Guardians' superior firepower and were unable to dislodge it.  Score: 523 to 151, Guardians of Spalding

Toast vs Team Floyd: This was the first matchup of the day of two teams that used treadless four-wheeled designs. The match turned into a shooting fight atop the hill, but each team burned through its ammo quickly, and it devolved into a bit of a ramming war, with Toast coming out on top. Score: 300 to 180, Toast

Round 2

The Riveters vs Guardians of Spalding: Both teams entered the match as the highest scorers from the previous round. The Riveters stuck with their strategy of taking the seesaw and the hill, taking an early point lead that they never surrendered. Guardians staged a comeback, showing the effectiveness of their cannons by scoring two direct hits on Riveters robots, but never managed to control the bases for long enough to rack up points. In the end, it was a blowout. Score: 708 to 80, The Riveters

Toast vs DA$ ROBOB0BOZ: During the autonomous first 40 seconds of the match, DA$ ROBOB0BOZ got a solid start by sending one robot dashing out into the obstacle field, poised to take the center base. However, with smaller wheels and a lower suspension than that of their competitors, the ROBOB0BOZ robot got hung up on one of the obstacles and had to restart at the base. The other ROBOB0BOZ robot lost a wheel, allowing Toast to take control of the center and leaving the seesaw uncontested while both teams duked it out for control of the hill. ROBOB0BOZ got lucky when one of their robots stopped suddenly and a ball rolled out of its hopper, striking a Toast robot in a questionable but legal hit. Toast managed to take the hill, suffering a short circuit in the blower motor that controls the cannon in the process. Smoke poured out of the Toast robot, which nevertheless survived until the end of the match. Score: 425 to 93, Toast

Team Floyd vs Ring of Fire: This match pitted Ring of Fire's custom tread design against Floyd's more traditional car-like design. Floyd's robots were in rough shape from the first round, but the team put on a strong showing. Robots from each team staged an ineffective shootout on top of the hill, with no clear victor, while Floyd suffered technical difficulties in the center. Ring of Fire took the seesaw, but dislodged one of its tank's batteries in the process and had to go back to the start. As both teams battled for the hill, one Ring of Fire robot took a spill off of the edge, crashing into the ground below upside-down and being knocked out of the match for good. With just one tank left in the fight, Ring of Fire were unable to score any further points, giving Floyd an easy victory. Score: 587 to 102, Team Floyd

Round 3

The Riveters vs Toast: By this time, the undefeated Riveters had emerged as the dominant team, having scored more than 500 points in both previous rounds. They used their seesaw trick again, while two Toast robots and one Riveters robot struggled to control the center base. Once again, the hill turned into a stalemate with each team pushing their respective buttons over and over. Toast dominated in the center, but the seesaw was worth more points, giving the Riveters the edge in a hotly contested match. Score: 395 to 122, The Riveters

Team Floyd vs Guardians of Spalding: This was another matchup of tank treads against the four-wheel car design. Floyd took advantage of the autonomous start to capture the hill first, but Guardians' superior cannon knocked the Floyd robot out and gave Guardians control of the hill. A battle for the center base turned into a crowded shooting match from which Floyd emerged victorious, as Guardians' treads kept getting hung up on the cardboard obstacles surrounding it. Two Guardians robots took hits, getting sent back to the start. The more accurate Guardians' cannons were able to knock out a Floyd robot from across the field, however. With seconds left on the clock, two Floyd robots charged up the hill, turning the contest into a shooting match. Ultimately, Floyd's ability to take and dominate bases gave them the match. Score: 469 to 363, Team Floyd

DA$ ROBOB0BOZ vs Ring of Fire: The audience waited anxiously to see whether Ring of Fire would be able to field its crashed robot once again. The team had to remove the robot's damaged cannon, but it was otherwise capable of competing. ROBOB0BOZ came out to a strong start, charging toward the center base. However, as the team's other robot climbed the hill, it overturned, spilling its ammo. Meanwhile, Ring of Fire came out aggressively, physically pushing the ROBOB0BOZ bot back, and sending it sliding sideways down the hill. A ROBOB0BOZ robot took the seesaw, but with a metallic grinding of gears as it struggled up the incline. In the final minute of the match, Ring of Fire retained its dominance of the hill while a single ROBOB0BOZ robot faced off against two Ring of Fire tanks on the obstacle field. Score: 479 to 332, Ring of Fire

Round 4

The Riveters vs Team Floyd: The Riveters were confident, having only needed one minor repair (gluing a broken sprocket) in order to field all three of their robots to Floyd's two. That gave the Riveters an advantage as they once again captured the seesaw. Floyd opted to capture the center and then used the fact that the Riveters were tied up with the seesaw to try to double-team the Riveters robot on the hill. But, as before, Floyd had trouble with the incline of the hill, and were only able to get one robot up to the top, leaving the hill in a stalemate. Score: 437 to 226, The Riveters.

Ring of Fire vs Toast: Since Ring of Fire could only field two robots, Toast started with the advantage, but the tide quickly turned when one of Toast's robots got hung up on an obstacle and started smoking. Ring of Fire capitalized on this problem by capturing the hill and the seesaw. Toast tried to rally by charging the hill, but flipped one of their robots on the ramp up. Down to a single robot, Toast charged the hill again, this time reaching the summit—only to be charged by the Ring of Fire robot guarding the hill. Ring of Fire notched its second win of the day. Score: 416 to 167, Ring of Fire

DA$ ROBOB0BOZ vs Guardians of Spalding: It was clear from the beginning that this would turn into a shooting match. Using two brushless motors attached to a pair of flywheels, Guardians' turrets were the team's biggest asset, and ROBOB0BOZ were not shy about opening fire either. When the match started, both teams charged the hill, but Guardians had trouble on the ramp and were beaten to the summit by a ROBOB0BOZ tank. Stuck at the bottom, Guardians lobbed long-range shots at ROBOB0BOZ. ROBOB0BOZ, however, proved both more agile and more accurate, shooting one of Guardians' robots and then charging down the hill to contest the center base. Ultimately, the speed and maneuverability of the ROBOB0BOZ robots gave them a remarkable and unexpected comeback, allowing them to dominate the round and earn their first win of the day. Score: 525 to 105, ROBOB0BOZ

Round 5

Ring of Fire vs The Riveters: Still undefeated, the Riveters were the clear favorite at the beginning of the round, but Ring of Fire were coming off of a big win against the team that had given the Riveters their closest match. Ring of Fire burned through both of their time-outs consecutively, which gave the Riveters a free opportunity to do some last-minute soldering on one of their robots. The Riveters took the hill and the seesaw in their opening moves. Ring of Fire charged the seesaw, but the Riveters held their ground, letting Ring of Fire get hung up on the obstacle field. The hill became zero-sum as both teams fought over it, so Ring of Fire took the center base while the Riveters kept the seesaw. Ring of Fire lost its presence on the hill as its tank—the same one that had gone over the edge of the hill earlier, damaging its treads—struggled mechanically. In the end, the Riveters stayed undefeated—and undamaged. Score: 684 to 99, The Riveters

DA$ ROBOB0BOZ vs Team Floyd: ROBOB0BOZ were riding high on their win from Round 4. Floyd, meanwhile, was demonstrating consistent difficulties in getting up steep slopes. In their opening moves, Floyd managed to take the hill and the seesaw. But then ROBOB0BOZ came out shooting. On the hill, robots from each team hit each other, leaving the hill temporarily unguarded. The gamble paid off for ROBOB0BOZ, who were able to retake the hill as Floyd had trouble getting back up the slope. Just when it seemed Floyd could be counted out, one of their robots charged the slope—and the ROBOB0BOZ robot came tumbling down. The ROBOB0BOZ staged a fiery, Nerf ball-blasting comeback, charging the seesaw. In the end, it was the closest match of the game. Score: 394 to 387, ROBOB0BOZ.

Guardians of Spalding vs Toast: Both teams were hoping to come back from multiple losses in a row. At the start, Toast launched both of their robots at the center base while Guardians tried charging the hill, only to get stuck and have to restart. Toast took the hill, and then fought Guardians at the seesaw and took control of that as well. Toast dominated all three bases as control issues kept Guardians' bots ineffectually spinning their treads and continually returning to the start. Guardians attempted to stay static and shoot at Toast bots from a distance, but they were unable to hit anything and the Toast lead increased. With 30 seconds left on the clock, Guardians managed to knock out the Toast bot on the seesaw, but it was too little, too late. Score: 596 to 123, Toast

At the end of the round-robin, The Riveters and Toast were the two highest-scoring teams, each earning a bye and advancing straight to the semifinals.


DA$ ROBOB0BOZ vs Ring of Fire: ROBOB0BOZ grabbed early control of the hill, but Ring of Fire quickly contested it. Meanwhile, each team charged the seesaw. Ring of Fire drove over the top of the ROBOB0BOZ bot, unable to dislodge it and ultimately throwing a tread, disabling the Ring of Fire robot. Both bots went back to the start, but ROBOB0BOZ had momentum. They got two bots to the top of the hill, double-teaming the Ring of Fire bot, which turned tail and headed over to the seesaw instead. However, it couldn't quite maneuver onto the seesaw itself to score points. With 45 seconds left in the match, the match was called for ROBOB0BOZ—and since they dominated the field completely uncontested, they set a course record with 724 points and went on to face the Riveters in the semifinals. Score: 724 to 36 points, ROBOB0BOZ

Team Floyd vs Guardians of Spalding: By this point in the day, both teams were facing mechanical failures, particularly with their drive mechanisms. With better mobility, Floyd got to the top of the hill first, but were unable to push the button that would give them credit for control. Guardians charged and claimed the hill instead. After a few minutes, Floyd's robots were all immobilized and had to be pulled back to the start. Unchecked on the field, Guardians took control of all three bases and racked up points for a blow-out victory. Score: 638 to 21, Guardians of Spalding


The Riveters vs DA$ ROBOB0BOZ: This was a highly anticipated match; if anyone could disrupt the Riveters' domination, it seemed it could be the rapidly ascendant ROBOB0BOZ. Following their tried-and-true strategy, the Riveters took early control of the hill and seesaw. However, for the first time, a ROBOB0BOZ bot charged the seesaw, unloading on the Riveters' robot. They exchanged fire in a flurry, and judges had to step in to sort it out. Ultimately, the judges ruled in the Riveters' favor, and the ROBOB0BOZ robot went back to the start. That was ROBOB0BOZ's high-water mark. Although the team also put on a spirited fight for the hill, they were ultimately done in by the hold-and-defend strategy of the Riveters. Score: 618 to 170, The Riveters

Guardians of Spalding vs Toast: Toast gained an early lead by charging the center base and the seesaw, then sending a robot up the hill—only to get shot by Guardians. Meanwhile, the fight for the seesaw got close and dirty, with the Toast robot tumbling down the incline, end over end. The match became a hard fight for all three bases that, in the end, became too close to call. To try to ensure their win, Guardians charged down the hill and shot up the center base. Toast used its superior power to charge and take the hill, which had been left uncontested. With 10 seconds left, even though Toast had taken more bases by the end, Guardians came out on top and moved to the final round. Score: 429 to 303, Guardians of Spalding

Final Round

The Riveters vs Guardians of Spalding: In the end, it came down to the teams that featured tank treads instead of car-like wheels. Sticking with their standard playbook, the Riveters claimed the hill and the seesaw right away. Guardians instead sent both of their robots into the center base, but they got hung up on obstacles and could not seem to put any points on the board. Guardians tried a stand-and-shoot strategy, but again could not hit any of the Riveters' robots. Finally, with a minute left on the clock and no points yet scored by Guardians, it became mathematically impossible for Guardians to win the match, and the round was called for the Riveters.

Written by Robert Perkins