Yaskawa Large Capacity Sigma II Series - Manual (Page 16)

1 For First-time Users of AC Servos
1.1.1 Servo Mechanisms
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1.1 Basic Understanding of AC Servos
This section describes the basic configuration of a servo mechanism and technical terms relating
to servos and also explains the features of
Σ-ΙΙ Series AC Servos.
1.1.1 Servo Mechanisms
You may be familiar with the following terms:
• Servo
• Servo mechanism
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• Servo control system
In fact, these terms are synonymous. They have the following meaning:
A control mechanism that monitors physical quantities such as specified positions.
In short, a servo mechanism is like a servant who does tasks faithfully and quickly according
to his master’s instructions. In fact, “servo” originally derives from the word “servant.”
Servo system could be defined in more detail as a mechanism that:
• Moves at a specified speed and
• Locates an object in a specified position
1 Servo mechanism
According to Japanese Industrial Standard (JIS) terminology, a “servo mechanism” is defined as a
mechanism that uses the position, direction, or orientation of an object as a process variable to control
a system to follow any changes in a target value (set point). More simply, a servo mechanism is a con-
trol mechanism that monitors physical quantities such as specified positions. Feedback control is nor-
mally performed by a servo mechanism. (Source: JIS B0181)
TERMS