Binari

Introduction

As you may know, we in Robojackets have a few rules that are strictly enforced: use safe shop practices, all robots name must end in "i", and NO WEDGES (no exceptions). After all, the weapon system is what makes a battlebot fun to design, build and watch. This being the case, 2 (two) weapons should be even better...Right? And so the motivation for this bot was to create a 2 weapon battlebot, specifically a double horizontal spinner.

Members:

• George 'Knute' Brady (Lead)
• Paul Matesevac
• Lucy Bricker
• James Peavy
• Joe Irwin
• Mannan Goel

Drive System

We decided to employ a shuffler drive system in order to take advantage of the 50% weight bonus granted by most (not all) competitions. This would allow us to make a double horizontal without gimping the weapons too much. The shuffler was a 4 foot assembly with holes drilled at 90 degree rotations along the length of the shafts. These holes would accept dowels which would then hold the semicircular cams. All of this would rotate inside ball bearings in the shuffle feet.

Electric:

Notes and Lessons:

• This system requires pretty careful machining and assembly. Misalignment and burs will cause jamming. Our problems were exacerbated by excessive waterjet taper on the cams, which can be partially resolved by reducing the machine-ability settings in the jet and then filing to fit.
• Ensure there is a collet for your shaft size and a machinists jack, as DIY solutions lead to inconsistencies.
• Provide ample protection for the shuffle system in your design. This drive system, while it can be as effective as wheels, is not as robust. Bent shafts, shifted plates, loose bearings can cause it all to fall apart and render you immobile after a big hit.
• consider designing the shuffler as modules, which can be swapped between matches. We made the mistake of basically locking the shufflers in with the rest our our chassis and had to basically take the whole bot apart to unbend the drive shafts and a fight.

Weapon System

Design Considerations

Because we had 2 weapons, it was important to have them be light enough as to not surpass a combined weight of ~15 lbs. The extra weight bonus from the shuffler allowed for this to be much more feasible (also required because we have 2x the weapon motors).

Weapon Design

Overall Design: Made to resemble Valkyri's overall weapon stack, minor changes were made to the overall design, A roller bearing (in design) was not needed at the bottom because of the constraint on the shaft itself (enough distance to spin without touching the bottom plate). This did not work, therefore a needle roller bearing should always be strongly considered in future live-shaft designs despite clearance looking good enough.

Weapon: Our weapons were waterjet out of AR500 steel (made from sheets of gun target steel). Each weapon was 0.5 inches in thickness and 11 inches in diameter. The overall shape was intended to put as much mass at the hitting ends as possible, there was no need to save weight therefore we were able to have a solid weapon. There was added structural support around the location that met with our weapon shaft, this was to theoretically prevent any snapping of the weapon (fears due to Apachi's weapon failure). Additionally, the weapon's geometry was made in order to ensure that at the maximum distance, only 1 point has the possibility of hitting (in order to reduce the chance of us 'skimming' the other bot instead of properly hitting it).

Belt Protection: Carbon fiber reinforced nylon material called Onyx, printed on a Markforged 3D printer. The print was not the best, therefore our belt protection was pretty non-existent. Also, the material may not have been a good choice, as carbon fiber doesn't resist instantaneous hits very well.

Lessons:

• Do not use our classical belts, use industrial/automotive belts instead
• Look for better protection for belts/weapon stacks (testing materials/more research)
• AR500 is sorta hard to machine (we need to basically increase the waterjet thickness, machinability, and possibly do 2 passes)

Weapon Stack and Weapon Pictures

Chassis System

• The chassis mostly consisted of aluminum, featuring of a ¼” top and side plates and ⅛” bottom plate.
• The front and back plates were made of HDPE, which bent to form Chonkii’s robustly round shape.
• The chassis had multiple rollers spaced out along its top, giving additional support to the shell track above.
• The central dead axle was constrained by two blocks, mounted to both the top and bottom plates. However, it was later determined that a single longer block with a key would constrain the shaft better than the two block system.
  • While drilling through the blocks into the shaft, a drill bit melted inside, acting as a makeshift pin (that was instantly destroyed in competition).

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 (whatever apachi used)
Weapon Motor	Scorpion SII-4035-250KV
Weapon Motor Controllers	Tribunus 06-120A (6S) Brushless ESC
Receiver	Hobby King 2.4Ghz Receiver 6Ch V2
Remote Control	Hobby King 2.4Ghz 6Ch Tx and Rx V2
Battery	Turnigy Heavy Duty 5000mAh 6S 60C LiPo Pack w/XT90 Turnigy Graphene Panther 3000mAh 3S 75C Battery Pack w/XT90

Competitions

AVC 2022

• Results: 0-2
  • Bracket Style: Double Elimination
    • [Binari (loser) V.S. Crippling Depression (winner): YouTube Link]
      • Crippling Depression was a wedge and undercutter combination bot.
      • As an undercutter, the weapon went underneath ours, slightly sheared one of our bolts
      • After getting flipped, they absolutely destroyed the weapon guards and side armor and bent our shuffler system and front plate
      • Lost via tap-out
    • [Binari (loser) V.S. HUHMWPE DUHMWPE (winner): YouTube Link]
      • Ripped off sideplate, and the shuffler system slowly fell apart
      • Lost via tap-out
      • More Description

Issues

• Stuff
• Other Stuff

Changes to make

• Stuff
• Other Stuff

Trivia

• The Vectrax was rendered inoperable twice by Chonki members (mainly Brian) during its construction.