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3.5
2 gain adjustment mode 1
Use the 2 gain adjustment mode to match the position control gains of each axes when performing the interpolation operation
of servo motors of two or more axes for an X-Y table or the like. In this mode, manually set the model control gain that
determines command trackability. Other servo parameters are set automatically.
For the 2 gain adjustment mode 1, manually set the model control gain that determines command trackability. The mode
constantly estimates the load to motor inertia ratio, and automatically set other servo parameters for optimum gains, in
accordance with the responsiveness of auto tuning.
Adjustment procedure of 2 gain adjustment mode 1
Precautions
• Set the same value in [Pr. PB07 Model control gain] for the axis used in 2 gain adjustment mode 1 and 2.
Procedure
Operation
1
Set to the auto tuning mode.
2
During operation, increase the setting value of auto tuning response ([Pr.
PA09]) and return the setting if vibration occurs.
3
Check the value of the model control gain ([Pr. PB07]) and the load to motor
inertia ratio ([Pr. PB06]).
4
Set [Pr. PA08.0 Gain adjustment mode selection] to "0" (2 gain adjustment
mode 1).
5
When the load to motor inertia ratio is different from the design value, set
[Pr. PA08.0 Gain adjustment mode selection] to "4" (2 gain adjustment
mode 2), then afterwards set the load to motor inertia ratio ([Pr. PB06]).
6
Set the model control gain of all the axes to be interpolated to the same
value. At that time, adjust the model loop gain ([Pr. PB07]) to the setting
value of the smallest axis.
7
During operation, increase the setting value of the auto tuning response
([Pr. PA09]), and return the setting if vibration occurs.
8
As the interpolation characteristics and the rotation status are visually
examined, increase the model loop gain ([Pr. PB07]), and return if an
overshoot occurs.
Servo parameter adjustment method
[Pr. PB07 Model control gain]
This servo parameter determines the response level of the position control loop. Increasing the model loop gain improves
trackability to the position command, but overshoot tends to occur at settling time. Number of droop pulses can be calculated
with the following formula.
Number of droop pulses [pulse] =
Position command frequency differs depending on the operation mode.
■Rotary servo motor and direct drive motor:
Servo motor speed [r/min]
Position command frequency =
■Linear servo motor:
Position command frequency = Speed [mm/s] ÷ Encoder resolution (travel distance per pulse)
Position command frequency [pulse/s]
Model control gain setting value
× Encoder resolution (number of pulses per servo motor revolution)
60
Description
Select the auto tuning mode 1.
Adjustment by the auto tuning mode 1
Check the upper setting limits.
Select the 2 gain adjustment mode 1 (interpolation mode).
Check the load to motor inertia ratio
Set the model control gain.
Adjusting servo stability
Adjusting position trackability
3 ADJUSTMENT METHOD
3.5 2 gain adjustment mode 1
3
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