ABSTRACT
The pneumatic actuating servo systems used in automatic devices have two major parts: the power and control subsystems (Figure 1.1).
The main part of the power subsystem is the motor, which may be of the rotating or linear type. Basically, this device converts pneumatic power into useful mechanical work or motion. The linear motion system widely uses the pneumatic cylinder, which has two major configurations: single or double action. For the single-action configuration, the cylinder can exert controllable forces in only one direction and uses a spring to return the piston to the unenergized position. A double-action actuator can be actively controlled in two directions. In the case of rotary actuation, the power unit is a set of vanes attached to a drive shaft and encased in a chamber. Within the chamber, the actuator rotates by differential pressure across the vanes and the action transmits through the drive shaft.
