Chonkiii

Robot Facts

Chonkiii With Flat Shell

Chonkiii With Tapered Shell

Chonkiii is the third iteration of a 45 lb shuffling shell spinner. The robot consists of a chassis that remains stationary relative to the ground and a rotating steel shell that surrounds the entire robot. Chonkiii aims to improve on the design of the previous iteration’s shuffling module by improving the components or areas we ran into issues with in competition. The goal is to design and implement a self-righting mechanism, a more durable shell, faster drive, and superior traction on the feet.

Now that Chonkii has seen competition, much of our design process focused on improving its durability and compatibility in competition. The self-righting bar extends up and outward from the robot, acting as a lever arm to push against the ground and shove it back up right. The shell was manufactured with a 50 degree slant to counteract horizontals and encourage more of a glancing hit than a direct one. The shell is also be manufactured out of a harder steel than Chonkii, which was made from un-hardened A36. The new shells are made from heat-treated 4140 steel, to prevent large dents that will cause the shell to wobble when it spins. More traction is needed to successfully compete with the speeds of the other robots, so the previous method of hot glue will be experimentally tested against new specially applied spikes.

Builder	GT RoboJackets (See below for members)
Drivers	Brian Epstein, Jacques Wang
Weight Class	30lb
Body Material	Aluminum Chassis, Heat Treated 4140 Shell
Weapon	24lb Shell with AR500 Impactors
Weapon Drive	2 X Scorpion 4035-380KV, Friction Drive
Drive	Turnigy Aerodrive 4250-500KV, Dual Cam Shuffler
Power	Weapon: 6S 2000mah MaxAmps for each weapon motor Drive: 5S 3250mah MaxAmps
Transmitter/Receiver	Taranis Q X7, FrSky X8R

Members:

• Sydney Baker (Lead)
• Mihir Nagaraj (Mentor)
• Brian Epstein (Mentor)
• Janie Edgar
• Jacques Wang
• Cade Tyler
• Dan Vail
• Christopher Bellflowers
• German Ortega
• Andrew
• Gray
• Maddie

Overview

At its core, Chonki is designed to absorb large hits and win through attrition. Chonkiii’s full body shell ensures that, when spun up, Chonkiii does not have a clear weak spot. The tapered shell is ¼” thick and weighs 24lbs. To accommodate for the increased weight, Chonkiii uses a shuffling drive system and utilizes a 150% weight bonus.

Chassis

The overall frame of the chassis forms a cylinder that fits inside of the rotating shell resting on top of it. The self-right bar extends from the top of the center shaft to enable the bot to re-right itself if it is ever flipped on its top. The HPDE side plates on each side of the bot provide protection for the internal electronics while also not adding much weight. These features can be seen in the image of the chassis below.

Drive

Chonki utilizes a shuffler system for drive. It consists of two shuffler modules, each with 4 UHMWPE feet. The feet sit on two parallel, keyed cam shafts. These allowed for the four feet to be positioned 90 degrees from each other, so feet would always be in contact with the ground through the cam shaft's rotation. To fit inside the feet get smaller as they move away from the chassis. The longer feet have fillets to clear the rollers and support which they sit under. The cams have offset keyed holes to accommodate the shafts and sit inside circular cutouts in the feet, which keep them parallel with the ground as it walks. The use of the shuffling system allowed Chonki a weight bonus, bringing the max weight to 45 lbs.

Weapon

Since the weapon on this bot also serves as its armor, it was imperative that the weapon be large enough for the robot to fit inside. An additional constraint was that it must be small enough that a reasonable thickness could be attained while still remaining under the desired percentage of the total weight of the robot (~50%).

Trivia

Chonk

• https://youtu.be/-03Uj4sr6hc