Yaskawa SGDB - Manual (Page 14)

FOR FIRST-TIME USERS OF AC SERVOS
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1.1 Servo Mechanisms
You may be familiar with the following terms:
• Servo
• Servo mechanism
• 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.”
TERMS
Servo mechanism
According to Japanese Industrial Standard (JIS) terminology, a “servo mechanism” is de-
fined as a mechanism that uses the position, direction, or orientation of an object as a pro-
cess variable to control a system to follow any changes in a target value (set point).
More simply, a servo mechanism is a control mechanism that monitors physical quantities
such as specified positions. Feedback control is normally performed by a servo mecha-
nism. (Source: JIS B0181)
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