BULKHEAD

Bulkhead: Tail-Swinging Beetleweight (May 2022 - November 2022)

BULKHEAD is a Thagomizer-style tail-swinging Beetleweight (3lb) robot, it competed once at NHRL, going 3-2 at their November 2022 competition. As this was my first beetle, I made quite a few design mistakes, but I learned a lot from the whole process of creating and competing with this bot. Many of these choices were rethought and the design was overall improved on in the successor BULKHEAD REDUX. The main theory behind BULKHEAD and other bots of its kind is to keep the front of the bot (the wedge) faced towards the opponent while the weapon spins up, then to drive forwards and "whip" the other bot with the horizontal spinner at the tail. This maneuver should hit the side of the opposing bot if executed correctly. BULKHEAD was designed with manufacturability in mind; I had not yet made any milled parts before starting this project and tried to design the bot around a range of processes including milling, FDM printing, heat bending, and some outsourced routed and waterjet parts. The main structure of the bot formed around a large printed TPU piece, chosen for its ability to take hits well and stay strong at low walls and infills, which saved a lot of weight. This TPU piece was sandwiched between two 3/8" 6061 aluminum panels, which I milled out of a flat sheet of stock (all milling for this project was done on a pre-NGC Haas Mini Mill). The wheels are made of cast FlexFoam 23 using a custom mold around a printed TPU hub. The electronics lids are made from outsourced 2mm carbon fiber. The 5.5" diameter disc was made of 1/4" AR500 steel. The wedge is 1.6mm 4130 Chromoly steel, outsourced for custom cutting, bent in house with an acetylene torch, with outsourced heat treating. I made two wedges for this bot, one wrapping around the front and one with flared ends. The flared wedge (or the "axolotl wedge," based on the shape) would be used for vertical spinners, as it protected the wheels, and the wrapped wedge would be used for horizontal spinners as the flared edges on the other wedge offer an easy catch point to rip the wedge off with. During the competition I only ran the axolotl wedge and it held up incredibly well, only being minorly damaged after a hit from Caldera and otherwise only scratched, even given the fight with Chubby Unicorn. BULKHEAD was not KO'd in any of its five fights, including the two it lost, but dealt with consistent driving issues due to fault drive ESCs. The main issues with BULKHEAD's design were the massively oversized height (over 3 inches) which added a lot of extra weight with the wedge, the weapon hub had hits putting structural screws in shear, which led to the weapon being completely unusable after its fifth fight, and the weapon belt was completely unprotected.