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Mechanical, Build & Pneumatics·Lesson 42 of 47

Field-Ready Reliability: Inspection, Spares, and the Pit Checklist

Turn a working robot into a reliable one: failure-mode triage, a pre-match pit checklist, spare-parts kit, and CAN/wiring habits that prevent dead modules.

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The mindset

Most matches are lost to reliability, not strategy. A robot that does one thing every match beats one that does three things sometimes. This lesson converts the prior failure modes into proactive habits.

The pre-match pit checklist

Run this before every match:

  1. Battery: charged, >12.4 V resting, securely strapped, and the main Anderson connector tight, loose battery leads cause brownouts.
  2. Fastener audit: wrench-check drivetrain, gearbox, and superstructure bolts. Re-seat anything backing out.
  3. Pneumatics: charge the system, confirm the high side reaches system max and the regulated low side reads ~60 PSI, listen for leaks, and confirm the system holds with the compressor off.
  4. Bumpers: within the legal mounting zone, numbers visible, hardware tight.
  5. CAN/wiring: tug-test motor controller and CAN connectors; a wiggled CAN wire drops a device mid-match. Confirm no flashing fault LEDs.
  6. Mechanism dry-run: in the pit, cycle every mechanism through its range and watch for binding or odd current draw.

Spare-parts kit (bring duplicates of failure-prone items)

  • A charged spare battery (always more than one).
  • Spare motor controllers and a spare motor of each type used.
  • Pneumatic fittings, tubing, and a spare solenoid.
  • Hex shaft stock, hex bearings (1/2 in hex), sprockets/belts, and assorted fasteners + nylocks.
  • Blue threadlocker, zip ties, electrical tape, and spare Anderson connectors.

CAN and wiring discipline

  • Strain-relieve every connector so vibration can't unseat it.
  • Keep CAN runs away from sharp edges and moving mechanisms; a pinched CAN wire kills the whole bus downstream.
  • Label CAN IDs and keep a wiring map in the pit. (Remember: PDP and legacy CTRE PCM at CAN ID 0.)

Triage during an event

When something breaks between matches: reproduce it, look at the failed part to read the root cause (per the gearbox/fastener lesson), apply the matching fix, and re-test the full cycle before queueing again. Don't ship an unverified fix to the field.

After the event

Keep a reliability log: what broke, the root cause, and the permanent fix. Teams that log failures stop repeating them season over season.

Key takeaways

  • Reliability wins matches: run a fixed pre-match checklist covering battery, fasteners, pneumatics, bumpers, CAN/wiring, and a mechanism dry-run.
  • Carry a spare-parts kit (extra batteries, motor controllers, fittings, hex shaft/bearings, threadlocker) for fast pit repairs.
  • Strain-relieve and route CAN/wiring away from moving parts (PDP/PCM at CAN ID 0), and never send an unverified fix back to the field.

Go deeper

Lesson quiz

Required

Answer all 3 questions correctly to complete this lesson.

1.Per the 2026 FRC robot construction rules, what is the maximum robot weight excluding bumpers and battery?

2.During pit prep, your inspection checklist flags the bumpers. Which of these reflects a current FRC bumper requirement?

3.What is the best practice for the pit when a critical mechanism (e.g., a swerve module or gearbox) fails between matches?

Answer every question to submit.