EURA SD20-G Series, Руководство пользователя

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SD20-G Series
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7.3 Gain Adjustment
7.3.1 Summary
To optimize the responsiveness of servo drive, the setting servo gain needs to adjust. Servo gain needs to
set for the combination of multi-parameter, they influence with each other, and therefore, the adjustment
of servo gain must consider the relationship of each parameter.
In general, the machinery of high rigidity can improve response performance by increasing servo gain.
For the machinery of low rigidity, vibration may occur when increasing servo gain. Therefore, in the
occasion of high response requirements, the machinery of high rigidity is needed to avoid mechanical
resonance.
The selection of position or speed response frequency must be decided by mechanical rigidity and
application occasion. In general, the machinery of high rigidity requires high response frequency, but
high response frequency can easily trigger mechanical resonance. If response frequency is unknown, user
can increase gain setting gradually to improve response frequency until the resonance happens, then turn
down the setting value of gain. Related gain adjustment principle illustrates as below:
The rigidity of servo drive is the ability that motor rotor overcomes load inertia, which is self-locking
ability of motor rotor. The stronger servo rigidity is, the bigger corresponding speed-loop gain is, the
faster system response speed is.
Servo rigidity must use in conjunction with the rotational inertia of load, the bigger mechanical load
rotational inertia is, the lower the rigidity level is. If servo rigidity is higher than rotational inertia ratio,
high-frequency self-excited oscillation would happen; whereas, motor would response slowly and take
longer to reach the specified location.
Servosystem consists of three control loops, from outside-in: position-loop, speed-loop, current loop,
basic control diagram shows as below:
速度前馈
位置环增益
速度反馈
滤波
速度计算
转矩前馈
速度环增益
速度环积分
时间常数
电流环控
制 X
X
位置指令
输入 +
-
位置
反馈
+
+
-
X
+
+
X
+
+
-
电流
反馈
M
编码器
Position
Instruction
Input
Speed
feedforward
Position
Feedback
Postion loop
gain
Speed
Cauculation
Speed
feedback
filter
Speed loop
gain
Torque
feedforward
Current
feedback
Current loop
control
Encoder
Speed loop
integral time
constant
Fig 7.3.1Servo drive internal frame diagram
Inside loop requires high responsiveness, system may not stable if not following the principle:
The default current loop can ensure the responsiveness that is not need to adjust. The position loop gain,
speed loop gain and other auxiliary gain needs adjustment.