Chonki Design Guide

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Revision as of 23:20, 29 May 2021 by Bepstein8 (talk | contribs) (Solid Concept)
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Chonki Design Guide

Chonki
Year Of Creation 2020-2021
Versions
Current Version V 1.0
Update Year 2020-2021
Wins/Losses 0/0
Information and Statistics
Weight Class Featherweight
Weapon Class Shell Spinner
Combined Wins/Losses 0/0
Weapon Speed 0 RPM on a pallet
Other Chonk!!!

Introduction

This robot had a name before a design. It born when Brian thought to himself, "Hey, it would be really funny if we named a robot Chonki and made it really, really big..." Throughout the design process the robot lived up to its name. Chonki is a 45lb shuffling shell spinner competing in the 30lb weight class. It was developed during 2020-2021. The drive system was iterated from that of Apachi. The weapon system was a brand new concept for BattleBots. The goal of Chonki was to evaluate the viability of shell spinners while taking advantage of the 1.5 time weight multiplier afforded by using a mechanism other than wheels for movement. Has not been to competition due to COVID cancellation, but showed promise during development.

Members:

  • Brian Epstein (Lead)
  • Dylan Fife (Mentor)
  • Mihir Nagaraj
  • Mesum Zaidi
  • Emily Liu
  • Janie Edgar
  • Celina Huang
  • Martha Leach
  • Cole Sosnowski
  • Colin Lyman

Drive System

Chonki utilizes a shuffler system for drive. It consists of two shuffler modules, each with 4 HDPE feet. The feet sit on two parallel, octagonal 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 chamfers to clear the rollers and support which they sit under. The cams have offset octagonal 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 System

Design Considerations

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%).

Nested Concept

Originally the shell was designed as a series of rings with progressively increasing diameters. The method of joining these rings together was thoroughly discussed. The two primary options were use of fasteners and through welding. This concept was advantageous because it allowed for the rings to be cut from sheets using the waterjet

Fastener Method

Advantages:

  • Avoids need to use welding (process with which we had little experience)
  • Simple to align via hole placement in ring

Easy to replace damaged bolts and or rings Disadvantages:

  • Bolts are likely to shear under stress from hitting other bots
  • Addition of holes to rings add stress concentrator, increasing likelihood of failure
Welding Method

Pros:

  • Very strong joint between rings if done correctly
  • Difficult to align rings and keep them aligned (flats were included on rings for this purpose, but a jig would still be required)

Cons:

  • A single piece means the whole thing must be replaced after damage
  • Welding is hard lol

Solid Concept

Instead of doing the nested concept, we simply decided to kill the Earth and mill the shell out of a massive block of steel.

Chassis System

Electronics

Drive Motors Turnigy Aerodrive SK3 - 5055-280KV Brushless Outrunner Motor


Drive Motor Controllers Flipsky Dual FSESC6.6 Based upon VESC6 with Aluminum Heatsink Mini Size
Weapon Motor Scorpion SII-4035-250KV
Weapon Motor Controllers AeroStar Advance 120A HV (6~12S) Brushless ESC (Opto)
Receiver Hobby King 2.4Ghz Receiver 6Ch V2
Remote Control Hobby King 2.4Ghz 6Ch Tx and Rx V2
Battery 2x Turnigy Heavy Duty 5000mAh 6S 60C LiPo Pack w/XT90

2x Turnigy Graphene Panther 3000mAh 3S 75C Battery Pack w/XT90