PNUEMATIC SYSTEMS CONTROL ENGINEERING PREPARED BY:- AADITYA A PATEL CHAUHAN JAY BIPINKUMAR DABHI YOGESH J MEHTA YAGNESH S SUBMITTED TO:- KRUNAL SIR

Pneumatic systems similar to hydraulic systems. Use compressed air as working fluid rather than hydraulic liquid. 70psi - 150psi, much lower than hydraulic system pressures, much lower forces than hydraulic actuators. Energy can be stored in high pressure tanks. Open systems, always processing new air. Pneumatic systems

Advantages: Constant force Clean (food industry) No return lines needed Adaptable infrastructure Possible light, mobile pneumatic systems Fast system response Disadvantages: Difficult to achieve position control (compressible air) Noisy

Key components of Pneumatic system Pump/Compressor Pressure regulator Valve Actuator

Valves Infinite position valve as shown in figure on right: allows any position between open and closed to modulate flow or pressure Finite position valve: has discrete positions, usually just open and closed. Ports: inlet and outlet connections to valve Finite position valve usually specified as “x/y valve” x: number of ports (sum of inlets and outlets) y: number of positions 4/3 valve: 4 ports and 3 positions

Types: Spool, poppet, ball, butterfly valves, etc. Types of Valves

Valve symbols

4 PORTS/3 POSITIONS SOLENOID SPOOL VALVE

Example: Pneumatic lift system (analogous to car jack)

Pneumatic actuators Cylinders with piston driven by pressurized fluid Single acting cylinder (SAC) Double acting cylinder (DAC) Two well-defined endpoints Rotary

Key parameters in choosing air cylinders Stroke length Bore size Pressure rating Mounting style Return type ( SAC vs. DAC) Spring force in SAC Loads Temperature range Lubrication Material Compatibility Force

Example 1: LEGO house builder Weight Stroke Speed Force Accurate positioning not required

Example 2: Anti-Lock Braking System Regular Automobile Breaking System Includes: Hydraulic actuation Pneumatic power assist ABS includes additional features: sensors valves hydraulic pump control unit

Pneumatic Power Assist Brakes applied Opens check valve to pressurize one side of diaphragm Pressure difference assist in applying braking force Pushes pistons in master cylinder Brakes released Check valve closes and engine vacuum is again applied to both chambers

REFERENCES Modern Control Engineering by Ogata Controlling Engineering by D Ganesh Rao Google images