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#
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#
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#
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.
the part worth keeping
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.
Mechanical, Build & PneumaticsPneumatics Fundamentals: How Air Becomes Motionlesson 1 of 3
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Sources and corrections
This lesson is AI-assisted: drafted from primary sources, then reviewed and edited by hand. Errors still get through. When one is reported we fix it and write down what changed, in public, in the corrections log.
sources and further reading
- firstinspires.orgFIRST Pneumatics Manual (Why Use Pneumatics)
- docs.wpilib.orgWPILib Docs - Pneumatics overview
clipped to this lesson
Articles that go further on this
The lesson gets you through the topic. These go wider on it, and they read in one sitting.
- 9 min readFRC Pneumatics: How to Design, Wire, and Program a Pneumatic SystemComplete FRC pneumatics guide: components, the REV Pneumatic Hub vs PCM, single vs double solenoids, safe wiring, WPILib programming, and the 60/120 psi limits./blogread it
- 18 min readFRC Power Transmission: Chain vs Belt, Sprockets, Pulleys, and TensioningA practical FRC guide to moving power from motor to mechanism: #25 vs #35 chain, HTD/GT2 belts, sprocket ratios, center distance, tensioning, and failure modes./blogread it
- 13 min readFRC Code Structure Best Practices: Command-Based Project ArchitectureHow to structure an FRC command-based robot project the right way — subsystems, commands, RobotContainer, and Constants — verified against official WPILib docs./blogread it
answer sheet
Lesson quiz
All 3 right completes the lesson. Miss one and only that question comes back, anything you already answered correctly stays banked.
0 of 3 answered
01In an FRC pneumatic system, what is the fundamental medium that is used to create motion and force?
02For most FRC mechanisms, a standard pneumatic cylinder is best described as which kind of actuator?
03Which electrically controlled component decides whether air is sent to a pneumatic cylinder to make it move?
Answer every question to submit.
All 47 lessons in Mechanical, Build & Pneumaticsopenclose
01 / prerequisites
02 / drivetrains
03 / power-transmission
04 / structure-materials-fasteners
05 / mechanisms-fabrication-assembly
06 / pneumatics-fundamentals
07 / pneumatic-components
08 / build-wire-program
09 / safety-rules-testing
10 / worked-examples-mini-projects
- Not read yet:Mini-Project 1: A Single-Jointed Arm From Math to Motion
- Not read yet:Mini-Project 2: A Two-Stage Cascade Elevator
- Not read yet:Mini-Project 3: A Velocity-Controlled Flywheel Shooter
- Not read yet:Mini-Project 4: A Pivoting Roller Intake
- Not read yet:Mini-Project 5: Integrating a COTS Swerve Module
11 / common-mistakes-troubleshooting
- Not read yet:Pneumatics Won't Fire: A Full Diagnostic Tree
- Not read yet:The Robot Won't Drive Straight (and Other Drivetrain Sins)
- Not read yet:Gearboxes That Grenade and Fasteners That Vibrate Loose
- Not read yet:Closed-Loop Mechanisms That Oscillate, Sag, or Stall
- Not read yet:Field-Ready Reliability: Inspection, Spares, and the Pit Checklist
12 / advanced-techniques-case-studies
- Not read yet:Characterizing Any Mechanism with SysId
- Not read yet:Simulation-Driven Design with WPILib Physics Models
- Not read yet:Motion Profiling and Superstructure Coordination
- Not read yet:Designing for Weight, Stiffness, and Manufacturability
- Not read yet:Case Studies: Learning From Open Alliance Robots