Page 17 - Fluid Power Engineering

xvi Co n t e n t s

Numerical Values of the Studied
System . . . . . . . . . . . . . . . . . . . . . . . . . 350
Torque Motors . . . . . . . . . . . . . . . . . . 351
Single-Stage Electrohydraulic
Servovalves . . . . . . . . . . . . . . . . . . . . . 352
Two-Stage Electrohydraulic
Servovalves . . . . . . . . . . . . . . . . . . . . . 354
Electrohydraulic Servo
Actuators (EHSAs) . . . . . . . . . . . . . . . 358
Appendix 10B Design of P, PI, and
PID Controllers . . . . . . . . . . . . . . . . . . . . . . . . . 361
11 Introduction to Pneumatic Systems . . . . . . . . . . . . . 367
11.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 367
11.2 Peculiarities of Pneumatic Systems . . . . . . . . . 367
11.2.1 Effects of Air Compressibility . . . . . 367
11.2.2 The Effect of Air Density . . . . . . . . . . 372
11.2.3 The Effect of Air Viscosity . . . . . . . . . 372
11.2.4 Other Peculiarities of Pneumatic
Systems . . . . . . . . . . . . . . . . . . . . . . . . 372
11.3 Advantages and Disadvantages of
Pneumatic Systems . . . . . . . . . . . . . . . . . . . . . . 373
11.3.1 Basic Advantages of Pneumatic
Systems . . . . . . . . . . . . . . . . . . . . . . . . 373
11.3.2 Basic Disadvantages of Pneumatic
Systems . . . . . . . . . . . . . . . . . . . . . . . . 373
11.4 Basic Elements of Pneumatic Systems . . . . . . 374
11.4.1 Basic Pneumatic Circuits . . . . . . . . . . 374
11.4.2 Air Compressors . . . . . . . . . . . . . . . . 374
11.4.3 Pneumatic Reservoirs . . . . . . . . . . . . 378
11.4.4 Air Filters . . . . . . . . . . . . . . . . . . . . . . . 378
11.4.5 Air Lubricators . . . . . . . . . . . . . . . . . . 379
11.4.6 Pneumatic Control Valves . . . . . . . . 379
11.5 Case Studies: Basic Pneumatic Circuits . . . . . 385
11.5.1 Manual Control of a Single-
Acting Cylinder . . . . . . . . . . . . . . . . . 385
11.5.2 Unidirectional Speed Control
of a Single-Acting Cylinder . . . . . . . 385
11.5.3 Bidirectional Speed Control
of a Single-Acting Cylinder . . . . . . . 385
11.5.4 OR Control of a Single-Acting
Cylinder . . . . . . . . . . . . . . . . . . . . . . . . 386
11.5.5 AND Control of a Single-Acting
Cylinder . . . . . . . . . . . . . . . . . . . . . . . . 387