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Safety·Lesson 15 of 28

Mini-Project: Write a Robot Lockout/Tagout (LOTO) Procedure

Adapt OSHA 1910.147 LOTO to an FRC robot: disconnect, lock, dissipate stored energy, verify zero energy, then a one-page posted procedure.

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Anyone reaching into a robot to work on it must first make it incapable of moving or shocking them. Lockout/Tagout (LOTO), governed by OSHA 1910.147 (The Control of Hazardous Energy), is the industrial standard. FRC robots have three hazardous energy sources: electrical (the 12V battery, which per WPILib can briefly supply over 180A and arc at over 500A when fully charged), pneumatic (stored air, with the working regulator set to 60 psi or less and the relief valve set to 125 psi per the pneumatics rules), and mechanical (compressed springs, stretched surgical tubing, raised arms, wound climbers).

Build the procedure as six concrete steps:

  1. Announce and prepare. The person doing the work calls out 'robot down for service.' Power off the Driver Station so no one can enable.
  2. Isolate electrical energy. Open the 120A main breaker (Cooper Bussmann 18X series, PN 185120F) AND physically unplug the battery at the Anderson SB-50 connector. Pulling the SB-50 is the true disconnect; the breaker alone is a switch, not isolation.
  3. Apply lock + tag. Slip a small padlock or a bright zip-tie tag through the disconnected SB-50 housing or over the breaker so it cannot be reconnected without the worker present. Write who locked it and when on the tag. No one but that person removes it.
  4. Dissipate stored energy. Open the required manual vent plug (FRC rules require an easily accessible manual vent valve that releases all system pressure without tools) until the storage and working pressure gauges read 0 psi. Lower any raised arm, relieve compressed springs, and discharge stretched tubing. Block any element that could fall.
  5. Verify zero energy. OSHA 1910.147(d)(6) requires verifying de-energization before work. Try to move the mechanism by hand and confirm gauges read zero. Confirm the robot is truly dead before trusting it; never presume.
  6. Release. Reverse the steps only when the work is done, tools are clear, and people are warned.

Deliverable - a laminated one-pager taped inside your pit and on the cart, titled 'Robot LOTO,' listing those six steps with your robot's specific gauge and breaker locations. Add a line: 'If you did not lock it, do not unlock it.'

This mirrors the OSHA sequence (notify, shut down, isolate, apply locks, dissipate stored energy, verify) scaled to an FRC robot. It directly prevents the most common shop injuries: a finger in a flywheel that someone re-enabled, or an arm slammed by a pneumatic cylinder during 'quick' pit work.

Key takeaways

  • Real isolation means unplugging the SB-50 connector, not just flipping the 120A breaker.
  • Always dissipate pneumatic (vent to 0 psi) and mechanical (springs/tubing/raised arms) energy before reaching in.
  • Post a six-step LOTO one-pager and enforce 'if you didn't lock it, don't unlock it.'

Go deeper

Lesson quiz

Required

Answer all 3 questions correctly to complete this lesson.

1.What is the primary purpose of a Lockout/Tagout (LOTO) procedure on an FRC robot?

2.On a typical FRC robot, what is the main energy source you isolate when applying LOTO?

3.In a correct LOTO procedure, what does the tag accomplish and who controls removal of the lock?

Answer every question to submit.