Servo - September 2015

36 SERVO 09.2015

BUILD REPORT:

Splatter: The Evolution of a Combat Robot

● by Matthew Vasquez

For nearly my whole life, I have been involved in the world of combat robots. Although my first Antweight fight was at the age of six, I have only been seriously competing in the Insect classes for a few years. After working on robots in the larger classes for so long, I wanted to try out the smaller ones. I liked the more relaxed atmosphere, and that events were held more frequently.

Splatter was my first Beetleweight combat robot. I originally created it to compete in the 2013 SoCal Mini Maker Faire “Robot Throwdown” competition. I decided on competing with a Beetleweight only a few days before the competition, so I thought I would build a simple under-cutter, using only leftover parts we had in our garage.

The robot consisted of a seven inch saw-blade, direct driven to a 35

mm brushless motor. The drive had four 50:1 Copal motors I found, hot-glued to a 1/8” aluminum base. The robot was not my best work, but was enough to enter into the competition.

I went into my first round against Squirty (a full body spinner), not knowing how my bot would hold up. Luckily, Squirty was not able to spin up to speed, so I was able to easily win the match, destroying one of my own drive motors in the process. Next, I fought the drum spinner called Jason’s Revenge. I really did not think I had a chance in this fight, but my undercutting saw-blade was low enough that the opponent’s drum hovered right over it, not able to catch on. I pushed him into the wall, causing his drum to hit the top of my robot launching him out of the arena, giving me a first place.

I knew I would never get this lucky again with the setup I had on Splatter, so I made some changes. I replaced the hot glue mounted Copals with four Finger Tech 33.3:1 Silver Spark motors, and Finger Tech L-bracket motor mounts. The robot was still very successful, taking a second Smashbotz 2014 Backyard Brawl. I The robot had plenty of pushing power with the Silver Sparks, but the motors were not holding up in combat with the current setup. So, I decided to try out the Kitbots 1,000 RPM motors with my own custom mounts.

The next event was another Robot Throwdown competition with five Beetleweights entered. My first match was against Jason’s Revenge. I was doing pretty well getting behind him, cutting up his wheels in the beginning of the match. Eventually, he escaped, going straight at me weapon to weapon.

The hit disabled my horizontal spinner, destroying the weapon motor. Jason’s Revenge went for one final hit, throwing me out of the arena. The drive was okay, but my weapon assembly was destroyed, forcing me to replace it with a Gorilla tape attached titanium wedge.

Although I had no weapon, I managed to win all of the rest of my matches by sliding underneath my opponents, and easily dragging them into the push-out.

I was very surprised by the success of the simple wedge, so I tried to think of a way to integrate it into a creative, yet destructive design. I eventually came to the conclusion that an overhead chop saw design was what I was looking for. I had seen some other successful overhead saw designs like SOB or Gloomy, but I didn’t want to build the traditional dust-pan design. I wanted to keep the four-wheeled drive platform I had done so well with.

I drew up some simple designs on Google SketchUp and immediately started building for the next Sonoma Ant Wars competition that would take place the next week. I cut off the front of the 1/8” aluminum base where the original weapon motor was