23. CONTINUOUS ACTUATORS

Topics:

• Servo Motors; AC and DC

• Stepper motors

• Single axis motion control

• Hydraulic actuators

Objectives:

• To understand the main differences between continuous actuators

• Be able to select a continuous actuator

• To be able to plan a motion for a single servo actuator

Continuous actuators allow a system to position or adjust outputs over a wide range of values. Even in their simplest form, continuous actuators tend to be mechanically complex devices. For example, a linear slide system might be composed of a motor with an electronic controller driving a mechanical slide with a ball screw. The cost for such actuators can easily be higher than for the control system itself. These actuators also require sophisticated control techniques that will be discussed in later chapters. In general, when there is a choice, it is better to use discrete actuators to reduce costs and complexity.