[KrazyCarl92]

One way that 5811 avoided this issue this year was to build the widest possible kitbot drive train we could with the existing holes in the kitbot rails and the belts that came with the KOP drive train. This meant ditching the AM upgrade kit, but had benefits of a higher track width:length ratio (the wider your wheelbase is relative to its length, the easier/smoother it is going to turn in a skid steer configuration).

We wound up with a 28.3" long by 30.5" wide chassis, and although we did not purchase the AM upgrade kit, we were able to use many of the aspects of their design (longer axle bolts, spacers, gearbox output shaft design) to make it work with the existing belts and frame pieces that came in the KOP. We were able to make it cheaper, and frankly I believe better performing that the upgrade kit you could buy. This worked DESPITE the center drop for the holes we used for our axles only being 0.070" (that is a really small center drop...). We also ran with 25 psi in the center wheels and 15 psi on the corner wheels, like Matt mentioned. No hard evidence that the exact pressures made any difference, but it worked and we liked it, so we ran with it.

We arrived at this solution as a constrained optimization problem. We asked ourselves that if constrained to the belts already in the KOP (to save on costs), what was the maximum track width feasible? We relied on CAD and basic math to help us answer the "feasible" question. There ended up being several modifications to frame pieces that were all individually simple, but did take some time and thinking to figure out.

The drawbacks to this design approach this year included having less clearance going through the dividers for defense crossing and some strange geometry concerns that would make scaling the tower more challenging because the bar was beyond legal reach while resting on the batter. We discussed the former before making the decision to make a wide bot, and decided that drive practice would be the appropriate solution. The latter drawback did not come up until later in the season when we wanted to add a scaler. That was so far down on our initial priority list that this drawback did not have a significant impact on our success this season throughout regional play, and really wasn't the hurdle that held us back later in the season either. Our strategic priorities played directly into our design trade off decisions with our drive train, as was the case with the other systems of the robot.