Introduction      Mechanical System      Electrical System      Strategies
 

Brannigan's Law is an autonomous robot built by Thomas Bulic and Michael Minbiole to compete in Northwestern University's design competition on May 13, 2000. This is an annual event where students build robots in order to face a specific challenge and in the process outperform opponent robots.

The course for 2000's competition, DC Cup 2000, is 16 feet long by 10 feet wide. Two robots will start each round in one of two designated starting areas which are at opposite ends of the course. In a three minute round each autonomous robot will run the course and attempt to collect as many golf balls as possible with the purpose of depositing them into one of two goals on the opposite side. The golf balls are placed in the same spots at the beginning of every round and those positions were known to the contestants prior to the competition. The goals are rectangular holes on the wall of the course whose dimensions and positions were also known prior to the contest. The team that has deposited the most balls into the goal wins that round. The robot that has collected the most balls wins the round if both teams have deposited the same amount of balls. In the case that both teams have deposited and collected the same amount of balls then the robot which is closer to its goal wins the round.

The nature of the course and competition was carefully considered in the early design stages. The appropriate strategies could be decided upon and priorities taken once information on the contest was available about six months before the competition. One of the most important things that would allow our team to fare well would be a reliable motion system. Since the course is predefined and the position of the golf balls do not change at the beginning of each contest, it would be imperative that our robot moved consistently and predictably. We realized that a control system based first on timing would be more reliable than one based on sensors alone. Sensors then could be added to aid in the understanding of the environment. Another important consideration was that the other team's robot would be competing against us on the course at the same time. This meant that there was the possibility that our robots will collide, that golf balls would be scattered by the other robot before we got there, and that the other robot would be able to deposit balls. In order to make our robot competitive against these factors, we needed to design it with the idea that a head to head competition is unpredictable.

We designed our robot to be big, strong, and fast in case there was a collision. This would allow us to collect as many balls as possible before a collision and thus winning the first tie-breaker and insure that our robot would work for the next round. There was also the problem of defending two goals. Our team's best answer to this problem was to include a smaller robot that would detach from the main robot as they are going up one side of the course. The smaller robot, whom we named Kiff, would then ride across the field, collect balls, and be an obstruction to the other team if they were coming down the opposite aisle.

The method of ball-collection also had to be considered. Our robot would need to collect as many balls as possible, lift the balls in order to deposit then into the raised goals, get to the goal reliably, and deposit the balls into the goals once there. We initially decided on a robot with treads in part because this configuration would leave us the most possible room for ball collection and would produce steady, reliable motion. A mechanism for collecting, lifting, and depositing would be complicated but vital in order to score and is discussed in detail in the mechanical systems section.

We would like to thank Ken Eguro for his invaluable help with the electrial system and Professor Kevin Lynch, our advisor for this project. Special thanks to FUBAR.

Introduction      Mechanical System      Electrical System      Strategies