Kinco CD3 Series - Chapter 7 Tuning Of the Servo System Control; Auto-Tuning

Kinco FD3&CD3 User Manual
87
Chapter 7 Tuning of the servo system control
Current loop
PWM
Motor
Feedbac
k
Notch filter
Observer
Lowpas
s
dx/dt
+
+
+
Speed demand
analog1
analog2
Torque demand
analog1
analog2
Profile generator
Current Demand lowpass Filter
Speed demand lowpass filter
Kpp
Kvff
kvp
Average filter
Profile
position
Actual position
+
Kaff
-
-
+
+
+
+
+
+
Real speed
Current
feedback
DCBUS+
DCBUS-
POWER
Profile speed
kvi
+
+
+
i-limit
Acceleration
feedforward
1 order
2 order
K-
load
∫dt
Figure 7-1: Servo system control block diagram
Figure 7.1 shows the servo system control block diagram. It can be seen from the figure that the servo
system generally includes three control loops: current loop, velocity loop and position loop.
The adjustment process of a servo system is used to set loop gain and filters to match the mechanical
characteristics, and finally to prevent the entire system from oscillating, to permit it to follow commands
quickly and to eliminate abnormal noise.
7.1 Auto-tuning
The auto-tuning function will try to stimulate the motor and load system by some motions, and get the
inertia of the load. If auto-tuning is successful, stiffness will be auto-set according to the inertia ratio.
Figure 7-2: Auto-tuning