Thursday, January 4, 2024

Spectrum 3847 | Build Blog 2024

 Welcome to our 2024 Build Blog. This is the 13th year of the blog. Our 2024 robot will be named “Ultraviolet 2024”

2024 Season Resources


Resources


Spectrum Design Guidelines 2024

We created some guidelines from our past experiences and design discussion over the fall. These aren’t rules so it’s possible and likely that we will break some of these but they are here to remind us that we may be going down a bad path if we are having to compromise on many of them. These are specific to our team, it’s entirely possible to build very competitive robots while doing things extremely different from us.


  • Don't do list

    • Don't be that far off the Meta design

      • If you're doing something real weird, stop and think real hard about it.

      • Does the advantage you think you are getting actually matter? Will it matter on Einstein?

    • No launching during pick and place games

    • No scissor lifts

    • No pinch/claw intake

      • Always spinning intakes with active eject when possible

    • No pink arms (Telescoping arm with center pivot)

    • No picking up flat objects at a steep angle

      • Did it in 17 and 18 and it was a mistake both times

    • No ramp bots

      • platforms/forks are okay, teams are very bad at driving up ramps

    • No Mecanum, h-drive, kiwi/Omni/x-drive, tank treads

    • No 6-32 bolts (4-40 and 8-32 will almost always work)

    • No pneumatics (20 motor slots now)

    • No small motors, no brushed motors

      • only NEOs/Vortex/Falcons/Krakens

      • no NEO55, 775pro, etc

    • No motors in rollers/tubes designs (neat but hard to maintain)

    • No lightening patterns

      • Waste time

      • Easier to bend or break

      • Doesn't save enough weight, use thinner materials instead

      • If you have to, circles work great and our fast (see 1114 2011-16)

    • No bumper or frame gaps (unless rules don’t allow extensions)

      • This prevents your frame from getting bent 

      • allows bumpers to take all impacts properly.

    • Don’t chase magic numbers

      • If there is only a single optimized dimension where your mechanisms function that normally means it’s not going to maintain throughout the season. Especially if one direction makes part of the mechanism easier and the other makes another part easier, trying to find that perfect balance is very difficult.

      • This could be an intake opening, a specific hood angle, etc.

  • Fasteners

    • 10-32 socket head

      • Alloy steel, zinc or black oxide coated

      • Nylock nuts or Nylock jam nuts, no regular nuts

      • Button or flat head when needed

    • 3/16 multi-grip rivets

      • Steel mandrel, aluminum head

      • Dome or countersunk

    • Use other bolt sizes sparingly only when required by some cots part or size requirements 

  • Use COTS parts effectively 

    • Besides cut plates, prints, standoffs, rollers, etc

  • Materials

    • REV MAXTube or other pre-drilled tube any sizes

      • 1/16” wall 1x2,2x2 when MAX pattern doesn’t work

      • ⅛” wall drivetrain tube

    • 1/16" or .09”, 0.25” aluminum

      • Can bend flanges for more strength

    • 1/16", ⅛", 6mm polycarb

    • ½" & ⅜" Rounded Hex Shaft

      • REV Rounded Hex ½” and 10-32 Spacer stock

      • WCP ⅜” rounded hex (7075)

    • REV MAXSpline shaft

    • Polycarb, PACF filaments

      • Don’t use PLA on comp robot mechanical parts, covers,etc is fine. (It works but we had issues with cracking last year)

  • ⅛in steel belly pan 

    • help with CG

    • unless we think we will need the weight other places

  • Swerve 

    • MK4i, L3 (likely)

  • Bumpers

    • ¾" Baltic Birch plywood (don't use cheap plywood)

    • Solid core round noodles

    • Nylon fabric

    • Large numbers for larger surface area

    • Bolts hold brackets to the wood, not wood screws

  • Use a mounting rail structure like 3538-2023 when possible

    • allows for clean belly pan electronics

    • Allows for mounting intake plates, etc all the way to the corners which is harder with the MK4i modules.

    • Allows for more cross bars if needed

    • Side plates can be enlarged for 2337-2022 style mounting

  • Handles

    • Handles should be integrated into the robot so that’s easy to carry on and off the field and allows more students to lift the robot easily

    • 2023 offseason handles - https://www.mcmaster.com/1897A52/

  • Power transmission

    • High torque/low speed

      • #25 chain, turnbuckle tensioners

      • MAXPlanetary+motor

      • MAX 90s work well

    • High speed

      • Motor pulley pinion

      • 5mm belt

      • 15mm wide when possible, 9mm if space is needed, much harder to rip 15mm

    • No Pneumatics

    • Support the end of motor output shafts with a bearing when possible

  • Shafts

    • ½” hex and MAXSpline shaft when possible.

    • Snap rings are good

      • Light, easy, reliable

      • Better to have snap rings and tapped 10-32 with washer in the ends 

    • Bearings for all fast motion

      • Launchers, intakes 

    • Bushings for slow motion is ok

      • Arms, wrists, pivots, etc.

  • Electrical

    • Battery

      • Flat mount battery on belly pan if at all possible

      • Battery strap with metal buckle

      • Zip tie battery connector every match

      • Leads always point up, NEVER to the side

      • 4 AWG wire

      • Blue Anderson SB120

    • Main breaker

      • NEVER OPTIFUSE!

      • Nord-Lock and Lock Nuts ¼”-28

      • 3D printed breaker shroud

    • 8-12 AWG for all motors

    • 18 AWG for device/aux power

    • 24 AWG for sensor wire

    • Inline Wagos for power

      • Kraken ring terminals direct to PDH

    • Inline dual clear lever nuts for can and signal/low current wires

      • 2 to 6 for swerve

      • 3 lever for LEDs, other sensors

    • Slim Ethernet cables

    • Mount radio above bumpers and away (6in +) from motors

    • Hot glue Ethernet and non-locking connectors

    • LED strips should be visible from all sides of the robot.

    • Cameras

      • Limelight for aiming

      • Limelight+coral for game piece tracking

      • Fisheye for driver camera, should be able to see intake

    • Sensors

      • Use internal encoders whenever possible, zero at boot and on a button

      • Digital Hall Effect sensors can be used for homing but not always needed

      • Sensors for game piece detection in intake/path

      • Swerve absolute encoders

  • Aesthetics

    • Primary purple powder coat, some white powder coat

    • Primary white vinyl wrap, some purple

    • White Polycarb

    • Addressable LEDs

    • Sponsor panels


  • Things to consider

  • Robot starting configuration

  • Handles and carrying the robot

  • Electronics layout, gyro, Rio, PDH, etc.

  • Wiring paths

  • Tether location

  • Make sure you have a plan to run the full autonomous while tethered, Ethernet reels, poles to hold the cable up, etc

  • Practice full matches, from cart to cart

  • Avoid shock loads on any systems, even if they work during testing, they will eventually cause damage over a whole season
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