Maryland FIRST RoboticsThe basics of pneumatics for FRC robots
Understanding pneumatics starts with a useful principle: compressed air can provide fast, controllable force without complex gearing. A pump or shop-air supply creates pressure, a regulator reduces and stabilises it, valves choose where the air flows, and cylinders turn that flow into linear motion. This makes pneumatics useful for intakes, shooters, elevators and other mechanisms that need repeatable movement.
Pneumatics also has trade-offs. Air is compressible, so a cylinder can accelerate quickly but may lack the precise position control of a motor. Tubing can stretch, valves can stick, and every fitting is another possible leak. FRC teams should therefore design the air circuit, measure actual performance and treat pressure regulation as part of the control system rather than an afterthought.
How pneumatic systems work
A pneumatic circuit has four functional areas: supply, conditioning, control and actuation. The supply stores or delivers air; filters remove debris and sometimes moisture while the regulator sets working pressure; the valve bank routes flow; and the cylinder produces the movement. A manifold distributes the regulated air, while a bleed or exhaust path lets air leave safely when a valve changes state.
Single-acting cylinders extend under pressure and retract with a spring, gravity or another load. Double-acting cylinders use air for both directions, giving better control over stroke timing. Rod diameter, cylinder bore, load and speed determine the force and cycle time, so “more pressure” is rarely the only answer to a weak mechanism.
For younger makers, Maryland FIRST’s Junior FIRST LEGO League pathway shows how hands-on robotics can build mechanical intuition before a student reaches FRC. That progression matters because learners gain confidence by handling real parts, tracing cause and effect, and revising a mechanism that does not yet behave as intended.
Choosing components and pressure
Start by identifying every pneumatic job on the robot. An intake may need a fast double-acting cylinder, while a height-adjustable mechanism might suit a spring-return single-acting cylinder. Separate high-demand functions with appropriately sized regulators so one actuator does not starve another during a match.
| Control approach | How it works | Main advantage | Main limitation |
|---|---|---|---|
| Fixed line pressure | One regulator supplies the circuit | Simple and inexpensive | All branches receive similar pressure |
| Regulated branch | A regulator sits near the actuator | Protects components and controls force | Response may be slow with an undersized regulator |
| Sensor-controlled branch | Valve operation and pressure feedback are coordinated | Repeatable motion and easier diagnosis | More plumbing, wiring and calibration |
Pressure and cylinder size work together. Force depends on pressure multiplied by piston area, so a larger bore can deliver more force at the same pressure. Retraction speed also depends on the rod-side area. Convert pressure before comparing components: 60 psi is about 414 kPa, while 80 psi is about 552 kPa.
Check component ratings, port sizes and tubing compatibility before assembly. Recent FRC rulebooks have capped pneumatic pressure at 80 psi, but teams must check the current game manual and rule updates for their season. Use pressure-rated connectors, secure cylinders to the frame and leave the regulator adjustment accessible for inspection.
Designing and controlling motion
Begin with the mechanism’s required sequence rather than a parts list. Define the start and finish positions, the load, the desired cycle time and what should happen if power is lost. A spring or gravity-assisted return can provide a passive fail-safe where appropriate, while a mechanical stop can prevent a cylinder from overtraveling.
Control begins with a voltage-controlled solenoid valve. A simple fixed-speed circuit uses valve timing and limit switches. A more capable design reads pressure through a supported transducer and uses feedback to command the valve, keeping the mechanism consistent as battery voltage, temperature or load changes. Closed-loop control does not guarantee perfection, but it exposes drift early.
A board-game design approach described by Avalokitesvaratrust illustrates the value of clear rules, visible feedback and repeated testing. FRC teams can apply the same mindset to pneumatics: sketch the sequence, act out possible failures and change one variable at a time. This makes disagreements about valve timing easier to resolve with evidence rather than intuition.
Keeping the system safe and compliant
Pneumatic energy can cause severe injuries, even at modest pressure. Never loosen fittings while a circuit is charged. Use eye protection during testing, keep hands clear of rods and gears, restrain hoses, and discharge stored pressure before maintenance. A compressor also needs ventilation, noise control and protection against hot components.
Follow the current FRC manual for pressure limits, venting, compressor use and prohibited equipment. Rules can change between seasons, and a mechanism that works in a workshop may still be illegal at competition. Record the relevant rule reference beside the design so mentors and the drive team can verify it.
In Australia, Safe Work Australia provides model workplace health and safety guidance, while state and territory laws and regulators apply locally. School and club activities need suitable supervision, risk assessment and safe storage. If a workshop uses fixed compressed-air equipment, follow the supplier’s handling requirements and the site’s pressure-equipment procedures rather than treating a student workshop as an unregulated industrial plant.
Planning for Australian conditions
Australian conditions affect pneumatic systems differently from one city to another. Melbourne workshops can face damp, changeable weather; Sydney’s salt-laden air encourages corrosion; Brisbane brings humidity and heavy summer rain; and Perth or Adelaide can experience hot, dusty conditions. Use corrosion-resistant fittings, protect exposed steel, wash intake filters and dry equipment after wet events. Test at match-like temperature because heat can also affect seals, tubing and compressor performance.
Transport is another everyday reality. Australian teams often move sizable robots in vans, trailers or trucks between meetings and competitions, so reservoirs, valves and cylinders must be secured. Drain the circuit before travel, cap open ports and protect cylinders from knocks. At home and in school workshops, mains electricity is generally 230–240 V, whereas FRC robots normally operate from batteries, so keep high-voltage bench equipment separate and use RCD-protected outlets where required.
The local parts market includes industrial distributors and online sellers carrying brands such as SMC and Festo, but stock and compatible fittings vary. Compare prices in Australian dollars, check delivery times and confirm that the regulator, valve, connectors and tubing work together before ordering. Imported components can take weeks to arrive, so allow buffer time before an event.
A practical build and test checklist
Build a low-pressure test rig before connecting the mechanism to the robot. Use a regulated supply, a pressure gauge, a protected valve and the shortest practical length of tubing. Record pressure, observe the full stroke, time the cycle and note any leakage or irregular motion.
Before assembly:
- Confirm the source, regulator, valve and cylinder ratings.
- Fit flow controls and keep tubing as short as practical.
- Mark ports, stroke limits and safe resting positions.
- Record the current FRC pressure and venting rules.
During testing:
- Begin near 30 psi and check every connection.
- Increase pressure in small steps while watching force and speed.
- Simulate low battery or sensor loss and verify a safe state.
- Repeat the cycle and log variation before tuning regulation.
Programming skills transfer well between LEGO-based activities and FRC mechanisms. Maryland FIRST’s coding through FLL kits story shows how beginners can practise control logic with accessible hardware. Pneumatics adds physical feedback to that logic: code commands a valve, sensors report position or pressure, and the team decides when the next stage may begin.
After each run, inspect seals, fittings and mounts before changing software. A leak may imitate a weak cylinder, while a partially blocked exhaust can imitate a sluggish valve. Divide the system into supply, control and output sections, then measure across those boundaries. This habit makes troubleshooting faster and gives mentors reliable evidence when they help.
Start building with confidence
Start with one simple FRC mechanism and draw its complete air path. Label the supply, regulator, valve, cylinder and sensors, then list the required forces, travel and safe resting position. A clear diagram exposes missing parts before anyone visits a shop or starts cutting tubing.
Choose rated components, build the lowest-pressure test rig that proves the sequence, and document every change. Consult the current FRC rules, local school procedures and an experienced mentor before competition use. Build the first rig, record the results and bring the evidence to your next team meeting.