Our robot is comprised of several critical modules which contribute to the overall effectiveness of our machine.

Four Bar Lift

The most critical modules of our robot is the four bar lift, which serves to raise and lower the bucket in gathering and scoring balls.  The four bar is designed in such a way that it keeps the bucket flat on the ground in the lowered position.  In the raised position, however, the bucket is tilted forward to accommodate dumping into the goal area.  A toggle is built into the four bar in the raised position so that the links bind and the lift does not require any holding force to stay in place.  A single servo and an external 5:2 gear ratio is sufficient to power this mechanism.  This required us to unlock the servo, which removed our ability to precisely control the servo's position.  Therefore, we strategically placed a bump sensor in the four bar lift which would indicate when the lift was both fully raised or lowered.

Jaw Mechanism

The jaw mechanism is uses a single servo to open two jaws, which gather and hold the balls in the bucket.  This is accomplished by driving one jaw directly with two gears and powering the other with a chain.  The same gear ratio is achieved on each path, allowing an even opening and closing motion.

Flag Box Interface Module

This module consists of a motor and two wheels which spin the flagbox mechanism.  A 25:1 gear ratio is used here to provide the proper balance of torque and speed to drive the flagbox.  This mechanism uses exclusively gears to transfer power, as it needed to be both robust and sturdy.  The two wheels allowed us to have a much larger error margin than other teams when we interfaced with the flagbox.

Main Drive Train

Our robot consisted of two driven wheels and two caster wheels.  We used a basic differential drive to power our vehicle.  Each powered wheel had a motor and a 75:1 gear ratio to ensure that our robot would traverse the map quickly and still have enough torque to handle any obstacles along the way.  Careful attention was payed to properly supporting the axles and beams while not overconstraining the structure.  We checked our motor currents and analyzed every interface for excess friction to ensure that there would be minimal efficiency losses along the drive train.

Servo Mounted Distance Sensors

We used two servos with distance sensors mounted on top to dynamically detect our position on the game board.  These servos were mounted on the front and back of our robot to provide us with increased vision and more effective feedback for our positioning systems.