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What Pneumatics Is and Why FRC Teams Use It

learnfrc.com
learnfrc.comAuthor
Veer Bajaj
Veer BajajMaintainer

Pneumatics is a branch of fluid power — using a pressurized fluid to transmit force. Hydraulics uses incompressible liquid (usually oil); pneumatics uses a compressible gas (in FRC, plain filtered air). A compressor squeezes air into storage, and when you let that air rush into a cylinder it pushes a piston and creates motion. Think of it as a spring you can charge and release on command.

The official FIRST Robotics Competition Pneumatics Manual compares it to construction equipment: a single pump feeds many valves, and each valve drives a cylinder, distributing power all around the machine. Your robot works the same way — one compressor charges the system, and several solenoid valves each command their own cylinder.

The Pneumatics Manual lists concrete reasons teams choose air:

  • Simple to control. A cylinder reliably moves to one of two end positions just by switching a solenoid. A motor needs sensors, encoders, or current limiting to hit a target and not destroy itself against a hard stop.
  • Durable. You can stall an air cylinder against a load indefinitely with no damage. Stall a motor and it overheats and burns out.
  • Strong and light. A 2-inch-bore cylinder applies about 188 pounds of force at 60 psi (pi x 1^2 x 60) with no gearboxes, chains, or sprockets. The valve-and-cylinder package is often comparable to or lighter than an equivalent motorized lift.
  • Adjustable force. Turn the regulator and you change the force everywhere downstream — no code change needed.
  • Fast to add late. Once one valve-and-cylinder pair is plumbed, adding another is just teeing into the pressure line and adding a few lines of code.

Pneumatic cylinders are two-position devices (extended or retracted), sometimes three with special hardware. They are not great for jobs needing variable speed or holding many in-between positions — that is motor territory. They also consume a finite, pre-charged air budget during a match, so a thirsty design can run out of air. You will learn to plan around both limits later in this department.

Classic FRC uses include game-piece intakes that flip down and up, grippers/claws that clamp, hood or ramp deployers, gear/hatch ejectors, climber latches, and shifting gearboxes between high and low gear. Each is fundamentally a binary job: in or out, open or closed — exactly what a cylinder does best.

  • Pneumatics is fluid power using compressed air; a compressor charges storage and cylinders convert that pressure into motion.
  • Air excels at simple, durable, two-position motion and can hold a stalled load indefinitely without damage.
  • A 2-inch-bore cylinder produces roughly 188 lb at 60 psi, often lighter than an equivalent motorized mechanism.
  • The main limitation is that cylinders are two-position and draw from a finite per-match air budget.

This lesson was adapted from learnfrc.com.