Pneumatics Level 2

Pneumatics 2 Purpose and Construction

The Hawk Collective 2890

https://firstfrc.blob.core.windows.net/frc2017/pneumatics-manual.pdf

Pneumatics Control Module

This is “little brain” of the pneumatics system. It controls all the safety parts of the system independently of the RIO.

Compressor A motor moves a piston that uses one way valves to move air out of the output. The system most often compresses the gas into a more dense state at higher pressure than standard atmospheric pressure

Accumulator This acts a reservoir for the air to “build up” in. The more of these you have onboard the fewer times your compressor has to turn on and off.

Air Pressure Switch Senses the pressure nearest the compressor (high pressure side) turning off the compressor when the pressure reaches a certain level. FRC=120PSI Top - analog. Can show pressure in driver station Bottom-binary. Can show if it is at max pressure

Safety Relief Valve Mechanical relief valve designed to fail, at a specific pressure venting excess pressure . FRC requrires it to mounted as close to output of the compressor as possible.

Gauge

Shows the pressure in that part of the system. A single system can have many gauges. PSI indicates how much pressure there is in the circuit or acting upon a specific part. Pounds per Square Inch

Regulator Used to lower the pressure (pushing force) between two segments of the pneumatic circuit.

Pressure Vent Plug Used to vent/purge the pneumatic system rendering it safe to work on.

Pneumatics Control Module } CAN IN and OUT It does not matter Which is which Just match the colors 18-16 Gauge 16 Gauge

Solenoids Single Double Signals from the RIO tell the PCM to send electricity down the red(+) and black(-) wires to allow the air to pass from one side of the device to the other or switch the way air flows in or out of the device. Level 3 - https://www.bibus.at/fileadmin/editors/countries/biaus/Pneumatik/Medien/ckd/Downloads/Elektrische_Einzelventile_Serie_4G.pdf

Solenoids There are 3 parts to most FRC solenoids. 1-Wire & connector 2-Coil Assembly (12v or 24v) 3-Solenoid Body 1 2 3

Solenoids To manually activate solenoids find the circular buttons behind the coil assembly. It is often a different color than the rest of the solenoid. Press it with a blunt object to temporarily activate it. Use a small slotted screwdriver inserted into the slot to press and twist the switch to lock it open.

Cylinder Uses air to move a rod in and out of the cylindrical body. They come in many styles, and sizes. Typically they are designated by their bodys diameter (bore) and how far the piston moves when activated (stroke). There are also mounting and end connector options as well as the ability to add a magnetic sensor to tell the Rio where that the moving part of the piston is at a specific location. Also known as a piston. Bottom Top 2in .75in L3 add calculations

Cylinder force calculations
To calculate the force available to the actuator: Area of piston x applied pressure Push = π r2 = 3.1412= 3.14” * 60psi= 188 LB/in2 Pull = Piston surface - rod area π r2 = 3.14.3532= .39” - 3.14 = 2.75” * 60psi= 165LB/in2 Push Pull 2in 2in .75in 60 psi L3 add calculations

Tubing FRC uses ¼ tubing. The ¼ (0.25) refers to the tubings outside diameter. Typically the inside diameter is closer to 0.15 inch. There can be pressure losses over long runs or if the tubing is deformed in some way such as being bent at too tight of an angle, pinched between two bodies, or wrapped too tightly around an immovable object.

Press fit connectors come in many sizes colors and shapes. The ¼ inch tubing used on the robot can be pressed in with little effort. If the End of the tube is PERPENDICULAR (square) to the length, it will make an air tight fit. If the end has been smashed or is not “square” the seal will be suspect and possibly leak or fall out under pressure. To remove the tube push in on the tubing, depress the plastic collar, and pull gently on the tubing. Press fit Connectors ¼ inch Tube

Flow Control Used to “slow down” air moving through an element (like a cylinder) by restricting the amount of air that is allowed to pass through it. This has the effect of making a piston move slower in the direction that flow controller is attached.

Pneumatics Control Module

} Outputs 4-7

} Outputs 0-3 12 or 24 Volt Jumper (One or the other) Solenoids can operate at 12 volts or 24 volts. The controller is Common Positive (+, HOT). The Negative (-,LOW) is the side that is switched on or off. The CAN bus sends the signals to an onboard controller that does the switching.

Pneumatics Control Module

} Outputs

} Outputs 12 or 24 Volt Switch (One or the other) Solenoids can operate at 12 volts or 24 volts. The controller is Common Positive (+, HOT). The Negative (-,LOW) is the side that is switched on or off. The CAN bus sends the signals to an onboard controller that does the switching. Compressor power USBC programming port Can bus Power in Pressure sensors

To achieve Pneumatics Technician Level 2 Complete Level 1 Pass Pneumatics 2 pre-test with 100% Assemble a complete functioning pneumatics board with one double action Solenoid and a double action cylinder.
Achieve 95% or better on Pneumatics Level 2 Test. Pneumatic Technician Level 3 Troubleshooting a Pneumatics system Pass Pneumatics 3 Test with 95% or better. Calculating volume, recharge rate, piston power, strokes per charge. Force at end of actuator.