Manual Tuning Of Gain Parameters - Delta ASDA-B3 Series User Manual

Tuning

5.6 Manual tuning of gain parameters

The position or speed response bandwidth is determined by the mechanical stiffness and the
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application. Generally, for applications or machines that require high-speed positioning and high
precision, higher response bandwidth is required. However, increasing the response bandwidth
is likely to cause mechanical resonance. Thus, machinery with higher stiffness is used to solve
this problem. When the response bandwidth of the machine is unknown, you can gradually
increase the gain parameter values to increase the response bandwidth. Then, decrease the
gain parameter values until you hear the sound of the resonance. The following are the
descriptions of the gain adjustment parameters.
 Position control gain (KPP, P2.000)
This parameter determines the response of the position control circuit. The bigger the
KPP value, the higher the bandwidth of the position loop. This lowers the following error
and position error, and shortens the settling time. However, if you set the value too high,
it can cause machine jitter or cause overshoot when positioning. The calculation of
position loop bandwidth is as follows:
 Speed control gain (KVP, P2.004)
This parameter determines the response of the speed control circuit. The bigger the KVP
value, the higher the bandwidth of the speed loop and the lower the following error.
However, if you set the value too high, it is likely to cause mechanical resonance. The
speed loop bandwidth must be 4 times (or more) the position loop bandwidth; otherwise,
it can cause machine jitter or cause overshoot when positioning. The calculation of
speed loop bandwidth is as follows:
JM: motor inertia; JL: load inertia
The following table illustrates the changes in position feedback when the speed loop
bandwidth is 1 time, 2 times, and 4 times the position loop bandwidth.
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Position loop bandwidth (Hz) =
Speed loop bandwidth (Hz) = (
Speed loop bandwidth: 100 Hz
Position loop bandwidth: 100 Hz
Position command
Position
Position feedback
Time
KPP
2π
KVP ( 1 + P1.037 / 10 )
) × [
2π ( 1 + JL / JM )
Speed loop bandwidth: 100 Hz
Position loop bandwidth: 50 Hz
Position command
Position
Position feedback
Time
ASDA-B3
]
Speed loop bandwidth: 100 Hz
Position loop bandwidth: 25 Hz
Position command
Position
Position feedback
Time