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FRC Pneumatics. Nate Laverdure FRC Team 122. Everything I wanted to know. FRC Pneumatics ,. but was. about. afraid to ask Chief Delphi. Nate Laverdure FRC Team 122. What is this presentation?. Goals: Teach you the words transducer , damper , and venturi. What is this presentation?.
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FRC Pneumatics Nate Laverdure FRC Team 122
Everything I wanted to know FRC Pneumatics, but was about afraid to ask Chief Delphi Nate Laverdure FRC Team 122
What is this presentation? Goals: • Teach you the words transducer, damper, and venturi
What is this presentation? Goals: • Teach you the words transducer, damper, and venturi • Attempt to: • Show that pneumatics have great advantages – if used correctly! • Provide a workable understanding of FRC pneumatics
What is this presentation? Goals: • Teach you the words transducer, damper, and venturi • Attempt to: • Show that pneumatics have great advantages – if used correctly! • Provide a workable understanding of FRC pneumatics My personal goal: inspire you to build your own pneumatic system!
What are pneumatics? Pneumatics use pressurized gas to effect a mechanical motion
What are pneumatics? Pneumatics use pressurized gas to effect a mechanical motion The working gas is typically air— 78% N2 21% O2 1% others
What are pneumatics? Other actuation systems: pneumatic pressurized gas hydraulic pressurized liquid electric electrical energy
What aren’t pneumatics? Closed-loop systems: • Pneumatic tires • Inflatable game pieces
What aren’t pneumatics? Closed-loop systems: • Pneumatic tires • Inflatable game pieces • Linear dampers (aka “gas shocks”)
Why should I use pneumatics? Strengths: • Linear motion • Adjustable force and speed • Good stall behavior (Can maintain high force, even with no motion) • Easy to configure • Low marginal weight
What is marginal weight? Actuators Electric motors Weight 2 5 1 3 4
What is marginal weight? Actuators Electric motors Weight 2 5 1 3 4
What is marginal weight? Actuators Electric motors Weight Marginal weight 2 5 1 3 4
What is marginal weight? Actuators Electric motors Pneumatics Weight Break-even point High initial weight 2 5 1 3 4
Why should I not use pneumatics? Weaknesses: • High initial weight • Severely limited available positions • Difficult to produce rotary motion • Capacity limits • Complex troubleshooting
Why should I not use pneumatics? Weaknesses: • High initial weight • Severely limited available positions • Difficult to produce rotary motion • Capacity limits • Complex troubleshooting Mitigations: • Add more actuators • Decreases average weight per actuator • Use off-board compression • Caution: more severe capacity limits!
Why should I not use pneumatics? Weaknesses: • High initial weight • Severely limited available positions • Difficult to produce rotary motion • Capacity limits • Complex troubleshooting Mitigations: • Either open or closed • No truly controllable multi-position actuators • Various hacks have come close • Caution: may not be legal in FRC 2014!
Why should I not use pneumatics? Weaknesses: • High initial weight • Severely limited available positions • Difficult to produce rotary motion • Capacity limits • Complex troubleshooting Mitigations: • Bell crank or other linkage • Rotary actuator (turbine) • Caution: severe capacity limits and extremely low torque!
Why should I not use pneumatics? Weaknesses: • High initial weight • Severely limited available positions • Difficult to produce rotary motion • Capacity limits • Complex troubleshooting Mitigations: • Use on-board compression • Caution: weight penalty! • Use lower operating pressures • Use spring-return cylinders
Why should I not use pneumatics? Weaknesses: • High initial weight • Severely limited available positions • Difficult to produce rotary motion • Capacity limits • Complex troubleshooting Mitigations: • Know your system! • Create and maintain a flow diagram • Practice responding to common problems
FRC pneumatics system HP MP LP
FRC pneumatics system Vacuum HP MP LP1 LP2 LP3 … LPn
FRC pneumatics system Vacuum Subsystems: HP MP LP1 LP2 LP3 … Compression Accumulation Safety Control LPn Control Actuation Control Actuation
Compression subsystem Components: • Compressor CMP HP
Compression subsystem Components: • Compressor Options: CMP HP Viair Thomas Alternatives 2011 - 2013 2003 - 2010 ??? - ???
Accumulation subsystem Components: • Accumulator TANK HP
Accumulation subsystem Components: • Accumulator Options: TANK HP ? Clippard Pneuaire Alternatives
Safety subsystem Components: • Pressure relief valve • Manual vent valve HP
Safety subsystem Components: • Pressure relief valve • Manual vent valve • Pressure relieving regulator • One on each leg • Pressure gauge • One on each leg HP HP MP MP LP
Safety subsystem HP HP MP MP LP
Control subsystem cRIO Pneumatic components: • Pressure switch • Solenoid valve PS HP MP or LP
Control subsystem cRIO Pneumatic components: • Pressure switch • Solenoid valve Electrical components: • Spike relay • Digital sidecar • Solenoid breakout module (cRIO) PS HP MP or LP
Control subsystem cRIO PS HP MP or LP
Diagramming the solenoid valve Position & flow boxes Left actuator Right actuator
Diagramming the solenoid valve Position & flow boxes Left actuator Right actuator Piloted solenoid with manual override External pilot Solenoid Spring Detent Lever Push button
Diagramming the solenoid valve Position & flow boxes Left actuator Right actuator 2-way 4-way 3-way 5-way
Example “This is a single-acting 4-way, 2-position solenoid valve with lever override.”
Example “This is a 4-way, 3-position, blocked center piloted solenoid valve with pushbutton overrides.”
Actuation subsystem Components: • Cylinder • Double acting • Single acting (spring return) • Rotary actuator (turbine)
Actuation subsystem Components: • Cylinder • Double acting • Single acting (spring return) • Rotary actuator (turbine) • Vacuum actuator • Venturi • Suction cup
Actuation subsystem Warning: Venturis require constant flow to maintain vacuum!
Optional components cRIO Pressure transducer Flow control valve PT
Optional components cRIO PT
cRIO PS CMP TANK HP TANK MP LP