pic: FRC Team 1425 Aerial Assist


How well is the Kiwi bot working for you? And how do your bumpers go on the short sides?

I always wonder when I see a Kiwi robot like this with the wheels sticking out, what are you doing in order to comply with R4?

In the STARTING CONFIGURATION, the ROBOT must constrain itself such that no part of the ROBOT extends outside the vertical projection of the FRAME PERIMETER, with the exception of minor protrusions such as bolt heads, fastener ends, rivets, etc.

Do you have another piece of frame that isn’t shown in this picture?

Yes we do. We have 1/8" sheet metal caps. Also our competition bumpers are single pieces and help protect from any direct damage to the wheels.

As Brennan said, we have wheel covers to define the frame perimeter and support the bumpers, just didn’t bother to put them on the practice robot. We also went with a single-piece bumper so that the outer corners are very solid, wheel protection should not be an issue.

As for the kiwi drive, it’s our second year with this setup. Last year we had zero maintenance or issues through two regionals, championships, and an off-season event (didn’t even change wheels, although we didn’t do too much driving as a FCS). It’s direct drive to the wheels, so there are no extra axles, chains, bearings, bearing blocks, chain tensioners, etc to worry about - just about as simple as it gets mechanically, yet you get full omnidirectionality. There is also no worry about losing contact with one wheel like on mecanum (3 points make a plane …), and little concern about weight distribution (though we like to have it well centered and low, worked out awesome on center of mass this year).

We switched from a 2 stage vex pro gearbox on 6" wheels last year to a single stage custom gearbox integrated in the frame rail with 4" wheels this year. Just like last year, we have 2 CIMs per wheel (6-CIM). Our drivebase (frame, gearboxes, belly pan, and wheels, no electronics) weighed in around 32 lbs this year, with half of that being motors.

Personally, I really like the new 112" sizing rule, it makes unusual setups like ours feasible to allow greater adaptation to the game (kiwi fit into the standard 28x38 would have been a big compromise for robot size and footprint, pretty much infeasible), and both years we have managed to create unique shooter solutions that would be difficult or impossible to package in the standard rectangular footprint. Odd-shaped robots do come with their challenges however - this one just barely squeezes through a door with the bumpers off, and there’s hardly a straight cut or even measurement anywhere (excepting the collector frame). If we hadn’t done CAD design throughout the process (for every fabricated part), many parts of this build would have been difficult or very frustrating to accomplish, instead it was near snap-fit construction from the very first build, and throughout the various iterations and additions - thorough CAD leaves you with a lot fewer surprises.

Still have some minor upgrades and tuning to do on the competition robot going into our first event, but hopefully all will go smoothly and it will get dialed-in quickly.