Components

Compressor

  • Generates pressure of 120 psi
  • Always run off relay module, in forward
    • Do not use to generate a vacuum!

Reservoir(s)

  • Up to two
  • Store compressed air at 120 psi
  • Top up before each match
    • Slow leaks can decrease pressure between pit and field
    • Tether robot beside field to top up pneumatics

Regulator

  • Allows air from reservoirs to flow to rest of pneumatic system
  • Limits pressure in valves, cylinders to 60 psi

Pressure Sensor

  • Detect pressure in pneumatic system
    • Indicate whether system is above or below a set pressure
    • Can be calibrated
  • Usually two (one set for 115 psi, one set for 105 psi)
    • Pressure below 105 psi: compressor on
    • Pressure above 115 psi: compressor off

Solenoids

Single Solenoid Valve

  • When energized, cylinder goes to one state
  • When de-energized, cylinder always returns to rest state
    • When power is cut at the end of the match, cylinder will return to rest state
  • Each valve powered by one relay module (only in forward)

Double Solenoid Valve

  • One solenoid pulsed to move cylinder one way, other solenoid pulsed to move cylinder the other way
  • Results unpredictable if both pulsed
  • Valve will stay in either state when neither solenoid energized
  • Can use one relay for each solenoid or one relay and two diodes

Cylinders

  • Force = Pressure × Area
    • 2" diameter piston
    • Area = 3.14 × 12 = 3.14 in2
    • Pressure = 60 psi
    • 3.14 in2 × 60 psi = 188 lbs
    • Force while extending greater than while retracting
  • Main decisions: Length and diameter
    • Diameter based on required force
    • Larger diameter: more force, but more air

Cylinder Tips

  • If you need the piston to stay extended or retracted, add a mechanical latch
  • Be careful to ensure the piston rod cannot get bent
  • Hard to get locknuts/lock washers in large sizes, so nuts on pistons likely to come loose

Flow Controls

  • Regulate flow of air into and out of a cylinder
  • Used to control speed of a pneumatic cylinder
  • If used, attach directly to cylinder (only one end needed)
  • Seems to regulate air flowing in both directions, but one direction is restricted a little more

Fittings

  • Put Teflon tape on all threads to ensure a good seal
    • Do not put tape on first two threads, as it may come loose and clog up a valve
  • Tubing attached simply by pushing it into connector
    • If you have a leak, try cutting off the last couple centimeters of tubing; if it is damaged, it will not seal properly
    • To detect leaks, put soapy water on suspect connections and watch for bubbling

Exhaust Valve

  • Use to release pressure (especially at the end of a match)
  • Useful if you need to be able to release a grabber after a match is over