Summa Series Servodrive Product Manual
Tuning
Document Version: V1.01
(Dec, 2019)
© 2019 ESTUN Automation Co., Ltd. All right reserved.
9-8
It is necessary to adjust the three-loop control parameters of the Servo from the inside out, that is, the
adjustment sequence is Torque loop → Speed loop → Position loop. In addition, in order to meet the
stability, the bandwidth setting should be the largest in the torque loop, the speed loop is the second, and
the position loop is the smallest.
The following parameters need to be adjusted in each loop when performing Manual Tuning.
Torque loop (Torque Control Mode)
−
Torque Reference Filter Time (Tf):
The torque reference filter filters the torque reference to remove the high frequency band, which
can effectively reduce the torque ripple of the Motor output, eliminate signal noise and reduce the
temperature rise of the Motor.
The larger the Torque Reference Filter Time, the better the filtering effect on the torque reference.
However, the greater the phase lag, and the slower the torque response. Therefore, a smaller
acceptable value should be set to obtain a larger torque loop bandwidth in the actual tuning.
Speed loop (Speed Control Mode)
−
Relevant parameter in torque loop (Tf)
−
Load Inertia Percentage (JL)
Properly setting the Load Inertia Percentage is a prerequisite for the tuning to obtain a better Servo
performance.
You can calculate the load inertia percentage (difficult and complex) by yourself, or you can get it
by the utility function Fn009 or by ESView V4, certainly, you can directly modify the parameters
by the host controller.
−
Speed Loop Gain (Kv), Speed Loop Integral Time (Ti)
The speed loop is controlled using a Proportional-Integral Controller that contains Speed Loop
Gain and Speed Loop Integral Time. Both of them determine the speed loop bandwidth and anti-
disturbance performance of the Servo.
In general, if you can increase the setting of the Speed Loop Gain, the speed loop bandwidth will
be increased and the anti-load disturbance performance will be better. And, if you can decrease the
setting of the Speed Loop Integral Time, the integral action will be stronger, the speed loop
bandwidth will be increased, and the anti-load disturbance performance will be better. In addition,
the integral action may reduce the steady-state error to zero.
Table 9-2 lists several commonly used adjustment methods based on the characteristics of the speed
step response.
Table 9-2
Adjustment example in speed loop
Response Curve
Description
Adjustment method
Speed loop bandwidth is high
Properly decrease the Speed
Loop Gain or increase the
Speed Loop Integral Time.
Speed loop damping ratio is
low
Properly increase the Speed
Loop Integral Time.
Steady-state error is existed
Properly decrease the Speed
Loop Integral Time.
