Mandi

Mandiii
Year Of Creation	2010-2011
Versions
Current Version	3.5
Update Year	2012-2013, 2014-2015, 2016-2017, 2017-2018
Information and Statistics
Weight Class	120lb Middle Weight
Weapon Class	Drum Spinner
Wins/Losses/Byes	12/10/2
("Temporary")	{"Temporary")
("Temporary")	("Temporary")

Competitions

RoboGames 2018

• Results
  • Win vs. Robotto
  • Win vs. Herbert's Revenge
  • Win vs. Railgun S
  • Loss vs. General
  • Semifinals - Win vs. Uppercut
  • Finals - Loss vs. General

RoboGames 2017

• Results
  • Loss vs. Cat Kong
  • Win vs. Houston
  • Loss vs. Nighthawk

RoboGames 2015

• Results:
  • Victory vs Heavy Metal
  • Loss vs Touro Classic

RoboGames 2013

• Results
  • Victory vs Witch Doctor
    • Mandii was initially knocked around and flipped over by the opponent
    • Opponent hits Mandii's weapon, flipped itself over as a result, and tried to tackle Mandii
    • This collision disabled the opponent's weapon/only means of movement
    • Opponent spewed smoke
  • Victory vs MPV
    • Opponent had no visible weapon/movement mechanism
    • Opponent was obliterated on 2nd contact by Mandii
    • Mandii sustained no visible damage
  • Loss vs The Blender
    • Mandii attacked frequently, but was pushed aside by the opponent's shell
    • Mandii is then viciously attacked by the enemy
    • Eventually, Mandii is disabled due to the damage sustained

RoboGames 2012

• Results
  • Loss vs Wolverine
    • Constant to-and-fro hits
    • Mandi was visibly damaged, while the opponent was not
    • Loss due to judge's decision

Versions

Mandi (V1.0)

Undocumented

Mandii (V1.0)

Created by: ______

Drive Motors	AmpFlow A28-150
Drive Motor Controllers	Victor 885
Weapon Motor	AmpFlow A28-400
Weapon Motor Controllers
Receiver
Remote Control	Hobby King 2.4Ghz 6Ch Tx and Rx V2
Battery
(OTHER:)	(OTHER:)

Problems

• Side Aluminum Armor Caved onto wheel from large hit. Prevented Drive
• Live Weapon Shaft
  • Deflected from hits
• Needle bearings supporting drum axle shattered
• Drum completely cracked through
• Plastic Skids Ripped off in fight
• Drum Teeth sheared off

Mandiii (V3.0)

Created by: Chelsea Silberglied, Trenton Charlson, Dustin Sloan

Drive Motors	AmpFlow A28-150
Drive Motor Controllers	Vyper
Weapon Motor	Castle Creations 2028 Extreme
Weapon Motor Controllers	Turnigy Monster 2000
Receiver	Hobbyking V2
Remote Control	Hobby King 2.4Ghz 6Ch Tx and Rx V2
Battery	Zippy Compact 5000mAh 6S 2 in series for weapon 1 for drive
Armor	2"x4" HDPE Bar Stock 3/16" 6061 AL Plate

Problems

• Low Clearance 0.5". Armor same height off ground as arena lip, got stuck on edge.
• Small Wheels (5"), Need to be large
• Difficult to service, required complete disassembly to replace belts and drum bearings.
• Weapon Pulley too large, belts vulnerable to hits. Also made of aluminum and easily damaged.
• Transmitter broke during competition. Used Hobbyking $20 Transmitter.
• 3D Printed Electronics Mount Broke
• Need Fastblow Fuse <300A
• Front Plate Fracture at screw interface with side plates, due to <0.125" material at bolt hole
• Weapon Bearings not checked after each match
  • One shattered during first match, still spun but quickly seized
• Drum bolt circle was not machined properly, drums canted.
• Large flat area on rear armor, got caught on arena edge
• Underweight (113 lbs)

Good aspects

• Reliable Drum
  • Spun up fast, <4 seconds
  • Drum in 2 pieces, 10 0.3125" Alloy Steel dowel pins
  • 4 Large Tapered Roller Bearings, 2 outside and 2 in the middle
  • Wire EDM Single Tooth (Montgomery Machining Mall), easy to hold tolerance
  • Hardness 53.5 HB, Heat Treated at Braddock Metallurgical Inc. for free. Did not fracture
  • Drum had dowel pin circle on both sides, could be reversed when pins broke inside and were stuck
• Powerful Drivetrain: 150lb-in Gearbox Output Torque, Could push > 130lb person on tile floor.
• All wheel drive, 4 Wheels
• Stable Drive Control, robot went straight and could turn appropriately
• Good Speed: 13.6 mph, 912RPM 5" Wheel
• Zip Tied and Electrical Taped all electronic connectors
• Armor absorbed hits well
  • Almost no significant damage to main frame
  • Aluminum dented and sheared
  • HPDE plastically deformed
  • Multiple replaceable sets (2.5 Sets)
  • Sheet Metal Screws, self tapping into plastic
• Tolerances
  • Parts fit together well. Waterjetted jigsaw fits had 0.008" under sizing to interface smoothly
  • Dial Indicated large parts on mill
  • Custom Grooving Tool for pulley V-belt groove
• Used Jigs to drill holes on side plates lengthwise (Holes could not be done on mill because the part is too long)
• External chain on drive easily serviceable
• Electronics properly spec'd. Did not burn an ESC
• Tapered roller bearing worked well

Changes/Improvements

• Larger wheels for ground clearance, 6" instead of 5"
  • Pockets and Slots in front plate, back plate, and side spacer to accommodate wheels
  • Make hub go all the way through wheel (not 2 separate inserts)
• Properly machined drum so that dowel circles line up
• Larger Drum to utilize extra weight
• Hole instead of H slot for belt servicing so that entire bot does not need disassembly to replace belts
  • Smaller weapon pulley required to accommodate hole
• Steel Pulley, not Aluminum
• No vertical holes in front plate
• Larger skids for larger wheels/drum
• Extra 2 Skids further back on side plates, redundancy in case front skids shear
• Hole in sideplate so that weapon shaft and drum can be removed without removing entire side plate
  • Insert attached to side plate to hold in place
  • Pocket armor to compensate for space
• Smaller Rear Armor
  • Make same profile as side armor
• More Powerful Weapon Motor (Scorpion HK 4530 450)
  • More Torque, faster spinup and smaller weapon pulley needed due to less gearing
• Brighter LEDs on top plate

Mandiii (V3.5)

Updated by: Nicolas Castro and Daniel Choi

Drive Motors	AmpFlow A28-150
Drive Motor Controllers	Vyper
Weapon Motor	Scorpion 450 HK-4530-450KV
Weapon Motor Controllers	Turnigy Monster 2000
Receiver	Hobbyking V2
Remote Control	Hobby King 2.4Ghz 6Ch Tx and Rx V2
Battery	Zippy Compact 5000mAh 6S 2 in series for weapon 1 for drive
Armor	2"x4" HDPE Bar Stock 3/16" 6061 AL Plate

Update sought to implement the changes wanted from V3 of Mandiii. Overall, the update made the back plastic armor thinner, allowed for a removable shaft, improved drive capabilities by utilizing bigger wheels and new wheel assemblies, and implemented a much larger drum.

Problems

• Newly designed drum was very heavy, causing the center of gravity to shift forward past the front wheels, making driving difficult. This was rectified by adding ballast steel plates under the back armor and only using one large drum piece.
• Motor pulley was too large, making it difficult to tension weapon and resulting in belt friction through the front plate.
• New drum pieces were slightly off tolerance, preventing proper press fit of bearings.
• Underweight (117 lbs)
• Retaining rings securing the forward shafts were removed by big hits, causing the shaft to slide into the chassis.
• Side plate bearings popped out of their press fit (on internal side of bot).
• Sprockets supporting chain drive sheared from wheel hub due to lack of intermittent tightening.
• Drive has too much torque, not geared well enough for speed.
• Tapered roller bearings almost always shattered
• Shaft became bent after powerful weapon on weapon hits
• Dowel pins sheared in drum pieces
• Hits to plastic armor caused deformation to cover access to screws holding armor in place
• Aluminum ripped off a little too easily

Good aspects

• See Mandiii V3
• Fairly easy to repeatably assemble fight after fight
• Only minor bends to chassis (shafts did banana-out, usually due to weapon on weapon contact)
• New wheels increased speed and had solid clearance with the edge of the arena. Did not get stuck.
• Drive system is extremely robust
  • Gearboxes showed no signs of damage after entire competition
  • Front drive failure did not hinder rear wheel drive
• Extremely durable, plastic armor absorbed all major hits
• Hits are powerful enough and can reliably deliver them
• Spin up was roughly the same (<4 sec)
• Low profile helped get under other bots

Changes/Improvements

• Use shaft collars instead of retaining rings, like Railgun S.
• Press bearings in facing outward to prevent it from popping out.
• Use keys between sprocket and hub in addition to thicker screws (10-32s)
• Change gearing for less torque (>20mph)
• Potentially use even larger wheels
• Use larger bearings to mediate shattering
• Follow up larger bearings with a larger shaft, potentially short to reduce bending moment (with no D).
• Increase size of dowel pins and potentially add more
• Single piece drum?
• Make outer plates thicker to reduce bending
• Make armor countersinks larger
• Use larger aluminum armor screws (do we need this aluminum armor? Something to think about).
• Overall, we need to evaluate what design changes will help with drum assembly integrity and what changes we can make to bring Mandiii to the next level.

Gallery

Notes:

Successor to Soafi 

• Mandiv Design Guide