Velocity feedforward of the position loop K_Velocity_FF : the velocity feedforward of a position loop can be
increased to reduce position following errors. When position signals are not smooth, if the velocity
feedforward of a position loop is reduced, motor oscillation during running can be reduced. Acceleration
feedback of the position loop K_Acc_FF (adjustment is not recommended for this parameter): If great gains of
position loops are required, the acceleration feedback K_Acc_FF can be properly adjusted to improve
performance.
* * _
K_Acc_FF
250000* 2 * *
pt
t
I K Encoder R
J
Note: K_Acc_FF is inversely proportional to the acceleration
feedforward.
Table 7-6 Parameters for gain control on position loops
Sets the response speed of a velocity loop
Adjusts speed control so that the time of minor
errors is compensated
You can reduce the noise during motor operation
by reducing the feedback bandwidth of velocity
loops (smoothing feedback signals of encoders).
When the set bandwidth becomes smaller, the
motor responds slower. The formula is
F=Speed_Fb_N*20+100.
For example, to set the filter bandwidth to "F = 500
Hz”, the parameter should be set to 20.
Proportional gain of velocity loop Kvp: If the proportional gain of the velocity loop increases, the responsive
bandwidth of the velocity loop also increases. The bandwidth of the velocity loop is directly proportional to the
speed of response. Motor noise also increases when the velocity loop gain increases. If the gain is too great,
system oscillation may occur.
Integral gain of velocity loop Kvi: If the integral gain of the velocity loop increases, the low-frequency intensity
is improved, and the time for steady state adjustment is reduced; however, if the integral gain is too great,
system oscillation may occur.
Multiple gains can be defined by DIN with the function “Gain Switch 0” and “Gain Switch 1” as shown in
following table.
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