2023:Drive Base

Calculations for the drive base perimeter and diagonal distance based on constraints from strategy and various subteam leads. Refer any questions to Nick L. or Berkeley P, class of 2023.

A basic sketch of the field including the community and charging station. For the double labled dimension, 51.8 is the length from the edge of the barrier base to the edge of the charge station. However, we later found that there is more space here if measured from the lexan to the charge station, effectively 59 inches. The minimum distance for the drive base diagonal is therefore 56 inches. Strategy requested a minimum of a 27 inch side with bumpers, 20.5 without. The intake subteam requested a minimum of a 30.5 inch side with bumpers, 24 without. These are the major constraints we worked with. Bumpers add an additonal 3.25 inches to each side, for a total of 6.5 extra inches.

Below are the calculations for a drive base with a width of 24 inches without bumpers, and a variety of lengths. The left column is the side length without bumpers, the middle column is the diagonal distance with bumpers, and the right column is irrelevant.

More qualitative drive base constraints

1/15/2023Based on our calculations, driver input, subteam and strategy requirements, and mentor approval, we first proposed to use a 26.25 inch by 30.25 inch drive base WITHOUT bumpers, and 32.75 inch by 36.75 inch WITH bumpers. This would allow us to have a diagonal of 49.225 inches, and a minimum extra distance of 6.775 inches while in the shortest part of the community. Additionally, a 12 inch by 10 inch square bumper cutout is necessary for intake.

Some extra calculations for a 26 inch by 24 inch drive base without bumpers.

1/17/2023

Drive base length has changed to 32.25 inches, at the request of the Lift subteam (They wanted 38 or 36 to feel good, but this would make the robot HUGE). Additionally, we have explored the suggestion to make cutouts in the central C-channel and make the drive base width 2 inches smaller. We have a working CAD of this model, but with a cylinder representing the movement of the swerve modules, and the 2 inches of width removed.

1/19/2023

We made a final decision on drive base. The frame is 24.25 inches by 32.25 inches without bumpers. There will be cutouts on the inside c-channel to allow the swerve drives to be closer to the inside c-channel. This decision was unanimously voted for at the meeting on 1/19/2023, with both mentor and student approval. We determined that the smaller space would not hinder pit crew in removing the swerve modules if necessary, and that the swerve wheels can rotate freely. Additionally, an FEA analysis of the drive base does not show significant stress on the area where material will be removed for the cutout, and the lead mechanical mentor assured us that it would be structurally stable. This change makes the overall drive base smaller, and brings the diagonal distance to 49.468 inches, leaving us 6.5 inches under our maximum distance of 56 inches.

Additional calculations for drive base with 28 inch and 29 inch length with a 24 inch width, excluding bumpers. Diagonal lengths include bumpers.