Our drive base this year consists a six CIM six wheel drop center tank drive. Each wheel is a 6” diameter pneumatic nylon wheel whose tires are 2” across. The wheels are arranged in a hexagonal pattern to assist with stability traversing defenses. We chose pneumatic wheels because they deform, providing traction and shock absorption while traveling over over defenses. The frame is an octagonal shape to assist with easily moving into defenses and making it difficult for opposing teams to defend.
We decided on kickoff day that our robot would need to be compact to fit under the low bar. In order to achieve a compact drivetrain, we decided to go with a chain in tube drivetrain. The chain that connects the wheels of each side of the drive base is strung inside of the drive tubes. Using this new design keeps the chain together by giving the chain no space in which to misalign and saves space on the robot frame.
There is a gap in the front of the drive base which assists with boulder intake. The edge of the sheet metal base guides the ball into the shooter while the shooter is in its lowest position. This channel also provides the intake mechanism an additional small distance of movement that enables the robot to open and move through the Portcullis.
On either side of the drive base there is a pneumatic cylinder which actuates our “stingers.” The stingers are designed to dislodge the robot if it becomes stuck in a defense or other position. They are designed to take up a minimal envelope of space so they curve around the drive tube and pivot on it. In order to get this shape, we had to use the CNC mill.