Project LiftOff

From NHRL
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Project Liftoff - September 2021 (rev 5.0), pictured before the September 2021 event. The bot went on to go undefeated, winning the 3lb division with 4 KOs and 3 judges decisions.

Project Liftoff is a 3lb MeltyBrain (a robot that moves using translational drift) as its entire body spins at 2000 to 4000 RPM.

As of September 2021, Project Liftoff is in it's fifth major design generation.

Project Liftoff - March 2019 (rev 1.0)
  • Rev-1.0 : March 2019
    • Processor: Arduino Nano
    • Accelerometer: common MPU 6050 (+/- 16g 12 bits)
    • Receiver Interface: standard RC-PWM into UART
    • Motor Control: OneShot125 via PWM manipulation @ ~800Hz
    • External Sensors: none
  • Rev-1.1 May 2019
    • switched from 8" Aluminum rings to 9" AR-500 ring with tooth (and hand cut HDPE)
      • this AR-500 tooth proved to be too pointed and became embedded in arena wall several times
Project Liftoff - May 2019 (rev 1.1)
Project Liftoff - August 2019 (rev 1.2)
Sir Pops A Lot (derivative) - August 2019 (rev 1.15)
  • Rev-2.0 : 2020
    • Processor: Teensy 4.0
    • Accelerometer: none… used motor eRPM telemetry from ESCs via bidirectional dShot
    • Receiver Interface: RC-SBUS into UART
    • Motor Control: dShot600 via SPI manipulation @ 8000Hz
    • External Sensors: active IR
    • CNC'd HDPE body
    • New 8" AR-500 ring and tooth (with a more blunt tip)
Project Liftoff - July 2020 (rev 2.0)
Flip N' Cut (derivative) - July 2020 (rev 2.05)
Project Liftoff - September 2020 (rev 2.1)
  • Rev-3 : 2021 Same electronics as Rev-2; improved algorithm, wheel orientation, and return to accelerometer (see March-2021 picture below).
    Project Liftoff - March 2021 (rev 3.0)
    • Processor: Teensy 4.0
    • Accelerometer: H3LIS331DL (+/- 400g 16 bits)
    • Receiver Interface: RC-SBUS into UART
    • Motor Control: dShot600 via SPI manipulation @ 8000Hz
    • External Sensors: active IR
    • changed to 4S (from 3S)
    • Other Details:
      • Switched to a "Motor Pod" that is sandwhich'd by two clam shell HDPE halves.
      • Put wheels in-line with weapon tooth (what was Jim thinking).
      • misc. software improvements (algorithm simplified)
  • Rev-4 : 2021 (May-2021 and July-2021) Same as Rev-3 except:
    • Quest for a more durable motor...
      • May-2021: created a custom motor with internal thrust bearing with "no-name" motors (internal thrust bearing still failed by the third fight).
      • July-2021: Put a thrust bearing inside a PropDrive motor
        • Combing a PD-2826 stator with a PD-2830 motor-can gave the needed room. Could do the same thing with a PD-2830 stator and a PD-2836 motor-can (the PD-2836 is really a 2834, 4mm larger than the PD-2830).
        • This motor sacrificed power for durability. It was durable... however, it changed the failure point to the set screws and motor axle.
    • Wheel Axis returning to 90 degrees from weapon
      • when wheels are inline with the weapon, the hockey-pucking is far worse.
    • Making weight distribution fully symmetric...
      • a large counter-balance weight opposite (single tooth) weapon increases hockey-pucking... an impact causes the tooth to stop, but the other side of the Bot goes flying due to its own momentum.
      • change to fully symmetric two weapon teeth, allowing us to avoid a large counter balance weight.
    • changed to full round HDPE body
      • prior HDPE cut-outs were to save weight
      • prior circular AR-500 weapon ring kept wall collisions "safer" and minimized pinning risk, and allowed us to hollow-out the HDPE.
      • re-design and re-cut of HDPE shell.
    • weapon ring changes
      • make weapon ring narrower to decrease weight to offset increase in HDPE
      • remove bolt holes from weapon ring (to maximize its strength)
    • July-2021: first usage of titanium wheels. Thank you to Joe Fabbiani (Smeeeeh) and Calvin Iba (Lynx) for sharing the idea and showing the way - see Lynx May-2021 competition.
  • Rev-5 : Sept-2021 Same as Rev-4 except:
    • Major Motor redesign
      • Switched from PropDrive 2830 to PropDrive 2836.
        • more power.
      • Changed to a Hub Motor wheel attachment
        • 6mm dead axle
        • two 626 bearings (1000+ pounds of dynamic load)
        • custom machined aluminum inner (motor-can) and out (wheel) hubs
          • done on home CNC machine (0.2mm layer height)
        • titanium wheels (via send-cut-send)
        • no more set screw failures!
        • Thank you to Brian Boxell (Eruption) for giving us some direction, encouragement, and help on Hub Motors.
    • Yet another AR-500 weapon ring re-design
      • Needed to find 80+ grams to offset the increased weight from the above Hub Motors.
      • Same 0.25" AR-500, but...
        • via send-cut-send.
        • Previous 326g (almost a full round circle) to 241g (almost rectangular)
        • Still no holes, very tapered/narrow in the middle.
    • Both the above required a re-design of HDPE shell.
  • Annotated Image of Sept-2021 Project LiftOff internals. The accelerometer and RC receiver are on the underside of the PCB.
    Rev-5 Issues that we hope to address for Nov-2021 :
    • In the "first attempt" of CNC'ing aluminum I made several mistakes that led to slight defects in the motor hubs (leading to non-alingment in the Hub Motors that were used... rubbing/friction/added heat/lost power).
      • Over-clamping & un-even clamping.
      • Slight alignment issues with double sided parts.
    • We never (software) tuned Project LiftOff... we were making hardware fixes until midnight on Friday.
      • The controls were upside down and backwards all day on Saturday.
      • The IR object/wall detection was never used since it was so misaligned.
    • Possibly make some ESC changes to improve drift performance.
    • Continue to ponder how to avoid "hockey pucking".
    • "Save the Arena Floor" upgrade...
      • We will modify the software to take advantage of the wheel telemetry information we have (via bidirectional dShot) to avoid "spinning our wheels".
      • This will not only stop us from ripping apart the arena floor (like a saw blade), but:
        • It will be much quieter.
        • It should enable us to spin up much faster (using static friction instead of dynamic friction).

Robot Facts

The first appearance was at the March 2019 NHRL event. The very first version used an 8" diameter aluminum pipe cut into two 1/2" thick slices with a notch cut out for the AR500 tooth (with two bolt holes).

Since then, Liftoff has used several laser or waterjet-cut AR500 steel rings. These rings have been sandwiched or otherwise mounted to CNC'd UHMW or HDPE bodies that contain the primary electronics and battery. This has proven to be a durable, and adaptable construction method.

Driver Andrew Kazmer (mostly) Jim Kazmer (sometimes)
Weight Class 3lb
Body Material HDPE (CNC) + AR500
Weapon Meltybrain Spinner
Weapon Drive NA
Drive 2 x Propdrive 2836 1200kv, 1.55" Titanium "Cleat" Wheels
Power 2x4S 650mah LiPo





Statistics

Record

Year Rank Events Fights W L % KOs KO'd Avg Time (s) KOs/F KO'd/F
2018-19 10 3 10 6 4 .600 4 4 - 40% 40%
2020 40 3 10 4 6 .400 3 4 - 30% 40%
2021 11 4 15 10 5 .667 6 2 - 40% 13%
All-Time 25 10 35 20 15 .571 13 10 122.8 37% 29%


Events

Date Reached Place Fights W L KOs KO'd
3/9/2019 Losers 2 3 2 1 2 1
5/10/2019 Losers Semifinal 3rd 6 4 2 2 2
8/10/2019 Losers 1 1 0 1 0 1
7/18/2020 Losers 3 4 2 2 2 1
7/19/2020 Losers 4 4 2 2 1 1
9/19/2020 Losers 1 2 0 2 0 2
3/20/2021 Losers 3 3 1 2 0 0
5/15/2021 Losers 3 3 1 2 1 2
7/24/2021 Winners 4 2 1 1 1 0
9/18/2021 Final 1st 7 7 0 4 0


Opponents

Opponent Fights W L KOs KO'd Last Meeting
Judge's Dream 2 2 0 0 0 9/18/2021
Jack Rabbit 2 0 2 0 0 7/19/2020
Wasp 2 0 2 0 2 5/10/2019
Be Careful What You Wish For 1 1 0 1 0 9/18/2021
Booooring 1 1 0 1 0 9/18/2021
Dark Princess 1 1 0 1 0 9/18/2021
Razor Storm 1 1 0 1 0 9/18/2021
Eruption 1 1 0 1 0 7/24/2021
OffTrack 1 1 0 1 0 5/15/2021
BB2X 1 1 0 1 0 7/19/2020
Sawmauri 1 1 0 1 0 7/18/2020
Yes 1 1 0 1 0 7/18/2020
Bad Bot 1 1 0 1 0 5/10/2019
Kill Joy 1 1 0 1 0 5/10/2019
Cookie Monster 1 1 0 1 0 3/9/2019
Maw 1 1 0 1 0 3/9/2019
Murple 1 1 0 0 0 9/18/2021
Black Adder 1 1 0 0 0 3/20/2021
Oops!.. I did it again.. 1 1 0 0 0 7/19/2020
Foiled Again 1 1 0 0 0 5/10/2019
Nitro Hornet 1 1 0 0 0 5/10/2019
SawMurai 1 0 1 0 0 7/24/2021
Caldera 1 0 1 0 0 3/20/2021
Silk 1 0 1 0 0 3/20/2021
Lynx 1 0 1 0 1 5/15/2021
Wumbo 1 0 1 0 1 5/15/2021
Cybot 1 0 1 0 1 9/19/2020
Shreddit Bro 1 0 1 0 1 9/19/2020
Jack Move 1 0 1 0 1 7/19/2020
Crisis 1 0 1 0 1 7/18/2020
Maelstrom 1 0 1 0 1 8/10/2019
SMEEEEEEEEEEEEEEEEE 1 0 1 0 1 3/9/2019

Click "Expand" to see this table.


Full Fight History

Date Opponent Round Result By Fight Length (s) Video
3/9/2019 SMEEEEEEEEEEEEEEEEE Winners 1 Loss KO 191 https://youtu.be/kkKFOXhK-N8
3/9/2019 Cookie Monster Losers 1 Win KO 87 https://youtu.be/NZ0MGYfzH1A
3/9/2019 Maw Losers 2 Win KO 110 https://youtu.be/GYPio_R9Nbw
5/10/2019 Wasp Winners 1 Loss KO 37 https://youtu.be/FXrn5Pc-kpM
5/10/2019 Bad Bot Losers 1 Win KO 36 https://youtu.be/Nk_Ww_wjG0g
5/10/2019 Kill Joy Losers 2 Win KO 35 https://youtu.be/slhqf76B28Y
5/10/2019 Nitro Hornet Losers 3 Win Judges Decision 240 https://youtu.be/w6PuIMEVgPA
5/10/2019 Foiled Again Losers 4 Win Judges Decision 240 https://youtu.be/KbC85bAwS1s
5/10/2019 Wasp Losers Semifinal Loss KO 22 https://youtu.be/wcSgpkXklus
8/10/2019 Tiny Huge Winners 1 Loss* Forfeit*
8/10/2019 Maelstrom Losers 1 Loss KO 153 https://youtu.be/_ErE7kddM80?t=1738
7/18/2020 Crisis Winners 2 Loss KO 61 https://youtu.be/l3PcB1StgFc
7/18/2020 Sawmauri Losers 1 Win KO 150 https://youtu.be/K2yvU7pGh7w
7/18/2020 Yes Winners 3 Win KO 55 https://youtu.be/sa132eFm5yQ
7/18/2020 Jack Rabbit Losers 3 Loss Judges Decision 240 https://youtu.be/MEa9t6DcClc
7/19/2020 BB2X Winners 2 Win KO 74 https://youtu.be/8wpOl1d6RNU
7/19/2020 Jack Rabbit Winners 3 Loss Judges Decision 180 https://youtu.be/a5t4JmN0osI
7/19/2020 Oops!.. I did it again.. Losers 3 Win Judges Decision 180 https://youtu.be/EPlzbLuOrVk
7/19/2020 Jack Move Losers 4 Loss KO 92 https://youtu.be/dGqAdWRw-fc
9/19/2020 Shreddit Bro Winners 1 Loss KO 50 https://youtu.be/43yxPZlrikE
9/19/2020 Cybot Losers 1 Loss KO 71 https://youtu.be/hUkh1w0jhno
2/6/2021 Drum Go Dum Winners 1 Loss* Forfeit*
2/6/2021 Horvoc Losers 1 Loss* Forfeit*
3/20/2021 Black Adder Winners 2 Win Judges Decision 180 https://youtu.be/MjKsedVz4zI
3/20/2021 Silk Winners 3 Loss Judges Decision 180 https://youtu.be/y-SpTxTiP_8
3/20/2021 Caldera Losers 3 Loss Judges Decision 180 https://youtu.be/-EwCzRLXJVo
5/15/2021 OffTrack Winners 2 Win KO 87 https://youtu.be/R2w6HwN-8A4
5/15/2021 Lynx Winners 3 Loss KO 43 https://youtu.be/5elaqlzA60k?t=16348
5/15/2021 Wumbo Losers 3 Loss KO 137 https://youtu.be/5elaqlzA60k?t=24734
7/24/2021 Unhinged Winners 1 Win* Forfeit*
7/24/2021 Bumble Hooves Winners 2 Win* Forfeit*
7/24/2021 Eruption Winners 3 Win KO 124 https://youtu.be/_X_fSdJPJvQ
7/24/2021 SawMurai Winners 4 Loss Judges Decision 180 https://youtu.be/KxIHvfQ52mA
7/24/2021 Bone Collector Losers 6 Loss* Forfeit*
9/18/2021 Be Careful What You Wish For Winners 2 Win KO 124 https://youtu.be/McNXHRM9n4I?t=1600
9/18/2021 Booooring Winners 3 Win KO 112 https://youtu.be/McNXHRM9n4I?t=13369
9/18/2021 Razor Storm Winners 4 Win KO 35 https://youtu.be/McNXHRM9n4I?t=20200
9/18/2021 Murple Winners 5 Win Judges Decision 180 https://youtu.be/McNXHRM9n4I?t=25276
9/18/2021 Judge's Dream Winners 6 Win Judges Decision 180 https://youtu.be/McNXHRM9n4I?t=28269
9/18/2021 Dark Princess Winner's Semifinal Win KO 73 https://youtu.be/9yJIdpltHgg?t=831
9/18/2021 Judge's Dream Final Win Judges Decision 180 https://youtu.be/9yJIdpltHgg?t=9587

* Forfeits are not counted in a bot's W-L record.

Click "Expand" to see this table.

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