“Ziptie”
In the fall of 2010, my high school decided to establish a team to compete in the 2011 FIRST Robotics Competition hosted by FIRST. The FIRST Robotics Competition (FRC) consists of a series of regional competitions where teams compete in practice, qualifying, and elimination matches to advance to the finals and then possibly to a national tournament. The competition’s kickoff would be January 8, 2011 and our robot would have to be crated and shipped by February 22.
As a member of my school’s new team, Team 3606, I was tasked with the role of lead programmer, although I helped with the physical building of the robot frequently. We quickly chose the name “Ziptie” for our robot due to the comically excessive amount of zip-ties we used in our design process before replacing them with actual bolts, welds, screws, nails and such.
2011′s Game: LOGO MOTION™
On January 8, members of our team picked up our kit of parts and watched as the 2011 game, LOGO MOTION™, was revealed. LOGO MOTION™ is a game in which two alliances, each composed of three teams and their respective robots, compete against each other to score points by hanging inter-tubes on scoring grids at either end of a 27 foot by 54 foot field. At the beginning of each two-minute match is a separate 15-second autonomous period where the robots can attempt to hang a special gamepiece called an “ubertube.”
Logomotion Playing Field
Programming the Robot
As lead programmer, my role was to work with the build team to program the robot to work under a set of specifications. I worked with my friend Jeremy Lopez to program Ziptie using Java, and in six short weeks we were able to interface our robot with two joysticks and the laptop “Driver Station” control panel provided by FRC, add autonomous functionality to the robot, and integrate several advantageous features into the controls that offered us fine control over the robot.
Open Source
I have released Ziptie’s source code for educational purposes with the hope that other FRC programmers can learn from it.
The Finished Product
After six weeks of work, Ziptie measured about 28″ x 38″ x 58″ in its starting configuration and weighed around 100 lbs. without its battery and bumpers. Ziptie features a double-jointed arm with a claw that opened and closed from the top. Controlling its six wheels were two motors in a two-wheel-drive configuration. Its arm was controlled by two window motors and its claw by a third. It had a remote-controlled camera with pan and tilt functionality, a functional gyroscope, three line sensors for following colored tape, and two functional encoders to measure arm and wheel rotations for use in the autonomous period. The robot was completely controlled via wireless radio from a laptop with two joysticks, one for the arm and another for the claw. Critical to the functioning of the robot was its code, totaling about 1,100 lines, which took joystick and computer input as well as input from the robot’s sensors and translated it into commands to the robot’s motors to compete in both autonomous and teleoperated modes.
Ziptie at work before competition
Competing in the 2011 Bayou Regional Competition
The Catholic High Bear Bots, Team 3606, competed in the 2011 Louisiana Bayou Regional in Westwego, Louisiana. Since it was our first year of competition, we were classified as a “rookie team.” Our performance at our first FIRST competition was quite a success. We were one of the first robots to pass inspection and play practice rounds, and we were able to score anywhere from 15 to 30 points on our own per game. We seeded high enough to get chosen to be on the #3 seed’s alliance and made it to the quarter-finals of the competition.
Our hard work earned us the Rookie Inspiration Award, which “celebrates a rookie team for outstanding effort as a FIRST team in community outreach and recruiting students to engineering.” You can read the publication in Catholic High’s Bear Facts II.