What Pneumatics Is and Why FRC Teams Use It
Fluid Power, the Air Version
Section titled “Fluid Power, the Air Version”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.
Why Reach for Air
Section titled “Why Reach for Air”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.
The Catch
Section titled “The Catch”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.
Where Pneumatics Shines on a Robot
Section titled “Where Pneumatics Shines on a Robot”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.
Key takeaways
Section titled “Key takeaways”- 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.
