Double Cheese was one of the robots that we built for the 2012 Vex Robotics World Championships College Challenge, and played as part of the AURA2 team which placed 11th after qualifications and finished as the quarter-finalists.
Double Cheese gets its name from the wedges on the front of its chassis. These allow it to drive through an isolation zone that is cluttered with lots of objects by forcing those objects upwards. Double Cheese uses an H-drive. Forward motors are four 393s (torque configuration) geared 2:1 for speed on 2.75” wheels. Strafe motors are two 269s geared 1.5:1 for speed on 2.75” wheels. These ratios are equivalent to 1.4:1 and 1:1 on 4” wheels.
The lift is a 6-bar designed to be able to score on all the 30” goals (both sides of the fence) on a college field, meaning it needs to be slightly taller than a high school 6-bar. To help achieve this, the long bar of the 6-bar offset by bolting it to the shoulder gear away from the centre. The 6-bar is also built slightly off parallel so that the ramp is at a lower angle near the bottom of its range and at a steeper angle near the top of its range. The lift is driven by four 269 motors on a 1:7 reduction (torque) with rubber band assistance. Two 269 motors drive 30-tooth sprockets as side rollers, with a 30” ramp for a six-object capacity. Other features include pneumatic drop-down intake rollers for descoring, and rubber band netting to prevent objects becoming stuck on the robot where they would prevent the lift from lowering.
Drive: 4x 393 in torque gearing at 2:1 on 2.75″ wheels and 2x 269s at 1.5:1 on 2.75″ wheels
Lift: 4x 269 at 1:7 Offset 6-bar lift
Intake: 2x 269 side sucker intake (30-tooth sprockets)
Pneumatics: Used on the intake to allow it to drop roughly 90 degrees for descoring top objects
Video of Double Cheese driving around the lab: http://www.youtube.com/watch?v=E0yphqVRWLA
Videos of Double Cheese playing in matches at the World Champs: http://www.youtube.com/playlist?list=PL0B00CF593F9116E9