Actuators

This chapter presents the dynamic models of automatic machines’ most commonly used actuators. The models are developed based on their physics and treated as lumped mass systems or discrete systems. Only DC electric motors are presented; they represent the majority of electric motors used in automatic machines, and their dynamic behavior is the basis for analyzing servo motors. The dynamic response of DC motors begins with the electro-mechanical interaction and the derivation of the electric and mechanical differential equations. Pneumatic systems are analyzed from the thermodynamics of the working fluid and its energy interaction with the moving parts, plus the electromagnetic performance of the actuating valves; while hydraulic systems are a particular case considering that the fluid is incompressible. These models result in a set of differential equations that describe the actuators’ dynamic behavior.