SRV-63 series AC servo drives Commissoning
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3) Speed loop integral time constant depends on the length of the positioning time. Please decrease
this value as small as possible under the precondition that the mechanical system does not vibrate.
4) After that, finely adjust the gain of the position loop, speed loop and the integration time constant to
find their optimal values.
Hereunder we illustrate several typical cases (in each case, only one parameter is changed relative to
a case when the parameters are appropriate):
Parameters are appropriate
In this case the parameters are set relatively appropriate. The motor speed can closely follow the
position command, the speed has basically no overshoot, and the positioning time is relatively short.
Speed loop integral time constant is relatively small
The speed loop of the servo drive must have high reaction speed. When the speed fluctuates, it
indicates that the stability of the speed loop is damaged due to the shorting integration time of t he
speed loop. This causes the servo motor to run unstably at fluctuating speed.
Speed loop integration time constant is relatively large
In this case, there is no apparent difference with the case when the parameters are appropriate. The
influence of the speed loop integration on the speed follow-up position command is not very high, but
too large speed loop integration time will delay the reaction time of the speed loop.
Gain of the speed loop is relatively high
In this case, the motor speed will fluctuate. The influence is the same as the case when the speed
loop integration time is too short. Both of them must keep coordinated. While increasing the gain of
the speed loop, the speed loop integration time must also be increased. Otherwise the servo system
will oscillate.
Gain of the speed loop is too low
Decreasing the gain of the speed loop will cause fluctuation of the motor speed to fluctuate. By
comparing with the case when the speed gain is too high we can know that the fluctuation frequency
of the motor speed is lower in this case which fully indicates that increasing the gain of the speed loop
can heighten the operating frequency of the system, improve the quick response performance of the
system, and effectively overcome the influence of the interference.
Gain of the position loop is excessively low
In the servo system, the operating frequency of the position loop is much lower than the speed loop.
When the gain of the position loop is too low, the system is difficult to eliminate the position deviation
formed during speed response. This can cause prolongation of the time interval of the motor speed
follow-up position command.
Gain of the position loop is excessively high
In the position servo system, the gain of the position loop also affects the stability. At this time, as the
gain of the position loop is excessively high, it makes the motor speed to fluctuate. Additionally,
comparing with the case when the gain of the position loop is too low we can know that the pure time
