Automatic Gain Adjustment - Parker FL20-CA Series Product Manual

parameter combinations, which influence each other. Therefore, parameter relation must be
considered for gain adjustment.
In general, response of high rigidity machine can be improved by increasing servo gain. But for
low rigidity machine, vibration may occur when servo gain increases. Therefore, if high
response is required, high rigidity machine is required to avoid vibration.
Response frequency of position or speed must be selected according to the machine rigidity and
application.
In general, high precise machining requires high response frequency, but high response
frequency may bring vibration. If allowable response frequency is unknown, user can increase
gain gradually to raise response frequency until vibration occurs and then decrease gain. Gain
adjustment principle is as following:
Servo rigidity is the ability that motor rotor withstands load inertia, which is self-locking ability
of motor rotor. The stronger the servo rigidity, the larger the corresponding speed-loop gain, the
faster the system response.
Servo rigidity must be used along with the load rotational inertia, the larger the load inertia, the
lower the allowable rigidity level. If servo rigidity is higher than inertia ratio, high-frequency
self-excited oscillation will occur. Otherwise, motor response is slow, motor takes long time to
reach specified location.
The servo system consists of three control loops, namely, position loop, speed loop, and current
loop from external to internal. The following figure shows the basic control block diagram.
Speed
速度前馈
feedforward
Position
位置指令
Instruction
输入 + Postion loop
位置环增益
Input
X
gain
-
位置
Position
Feedback 反馈
Fig 9.3.1 Servo drive internal frame diagram
The most internal loop must have the highest response. If it is not observed, the system may be
unstable.
The default current loop gain of the servo drive ensures the response, and need not be adjusted.
You only need to adjust the position loop gain, speed loop gain and other auxiliary gains.

9.3.2 Automatic Gain Adjustment

Automatic gain adjustment means that the servo drive automatically produces the matching gain
parameters based on the setting of Po010 (Rigidity level selection) to achieve fast response and
stability.
Torque
转矩前馈
feedforward
+
+ + +
Speed loop
X X
速度环增益
- gain
+
电流
Current
feedback 反馈
速度环积分 Speed loop
速度反馈 Speed
integral time
时间常数
feedback
滤波 constant
filter
Speed
速度计算
Cauculation
294
M
+
电流环控
Current loop
X
control 制
-
编码器
Encoder