Gucci

Introduction

Gucci is the sumo robot created by Battlebots between Summer and Fall of 2018. It competed in the 2018 All-Japan Sumo Robotics Competition in Tokyo, Japan. It was the first of the next line of sumo bots in RoboJackets after the Pushi line. This guide is designed to walk you through our process for designing Gucci. We hope you can learn from our successes and failures when designing your own Sumo bot.

Gucci was defined by being the successor to Pushiv. Pushiv did not win a match at its competition, our main goal was to win at least one match. This may be in actuality too high of an initial goal, but when we looked into how we could stand a better chance there were some clear directions. Pushiv was a very unique sumobot, primarily in its use of worm gears. The purpose of Gucci was to create a solid bot that sticks close to the meta. Instead of trying something untested, we wanted to create a quality sumo robot that future bots could build from.

Mechanical Design

Drive

Introduction

We designed the drive wrong with Gucci. If you want to know what we think is right, scroll down to Gucc$$$. The mistake we made was that we believed we should be designing around a desired speed and then picking a reasonable acceleration. Turns out, when you do this you reach your target speed but drive off the edge. Because of this blunder, we used a fraction of the power our motors could have output. This is what really cost Gucci from being a competitive sumobot.

A general tip for sumo drives is to plan to use shims. Shims are very thin spacers. The spacing of the drive components is very important, especially because a small change in magnet height drastically impacts its force, and using shims can help you correct tolerancing issues or wheel deformation.

Design Decisions

We got really nice motors from Maxon, which came down to our budget and negotiating a discount. We used these gears, which seemed standard from Jsumo, with a 4.3:1 gear ratio. We used these wheels from JSumo, which in reality were a millimeter less in diameter than advertised. In addition, they deformed about another millimeter.

Differences from Pushiv/How it fits the Meta

We did not use worm gears. We used a much lower gear ratio, because it appeared to us that speed was much more important in the meta than Pushiv had been designed around.

Exterior

Walls on a sumobot are only important for protecting your electronics, and potentially mounting sensors. Unlike battlebots you won’t be facing any weapons, but there is a high likelihood of your robot being flipped. If your walls are well designed, the electronics won’t take the brunt of the impact when the robot lands. Our walls were 1/8” HDPE, and while they were not used intensively we did not see a problem with that design.