DA98E Series AC Servo Drive Unit User Manual
6
4) Glossaries with regard to Servo Control
The servo system is provided with three basic control modes: position control, speed control and
torque control. The block diagram of the system is as shown in Figure 1-6.
z
Position control:
The direction and angle of rotation of the motor are set by means of digital
pulse or data communication. The servo unit controls the motor rotor so that it rotates by a proper
angle in the given direction. Both the angle (position) and speed of rotation are controllable.
z
Speed control:
The direction and angle of rotation of the motor are set by means of analog
voltage or data communication. The servo unit controls the motor rotor so that it rotates in the given
direction at the given speed.
z
Torque control:
The amplitude and direction of the output torque of the motor are set by
means of analog voltage or data communication. The servo unit controls the direction of rotation and
output torque of the motor rotor.
The servo unit described herein currently does not receive any torque setting signal or provide
torque controlling mode.
PG
Position
feedback signal
－
＋
Power
amplification
Current
adjustment
＋
Speed
adjustment
－
＋
Position
adjustment
－
Command
position
Speed feedback
signal
Current feedback
signal
Position
controller
Speed
controller
Current
controller
Motor
Figure 1-6 Block diagram of three-loop control
5) Indexes of Servo Performance
Characteristics of servo dynamic response:
the response speed, dynamic control error and
steady-state control error. Figure 1-7 is the response characteristic diagram of the given step signal
from the servo signal (The solid line indicates given signal and dotted line the output signal from the
servo system in the following text.):
Summary of Contents for DA98E Series
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