Panasonic MINAS A5-series, Operating Instructions Manual

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5
5. Manual Gain Tuning (Application)
Adjustment
Feed forward function
Outline
When position control or full closed control is used, positional deviation can be further
reduced when compared with deviation where control is made only by feedback, and
response is also improved, by calculating the velocity control command necessary for
operation based on the internal positional command, and by adding velocity feed forward
to the speed command calculated by comparison with position feedback.
The response time of the velocity control system is also improved by calculating torque
command necessary for operation based on the velocity control command and by adding
torque feed forward calculated by comparison with velocity feedback to the torque
command.
Related Parameter
For A 5 series, the velocity feed forward and torque feed forward can be used.
Class No. Title Function
1 10
Velocity feed forward
gain
Multiply the velocity control command calculated
according to the internal positional command by the
ratio of this parameter and add the result to the speed
command resulting from the positional control process.
1 11
Velocity feed forward
filter
Set the time constant of 1st delay filter which affects the
input of velocity feed forward.
1 12
Torque feed forward
gain
Multiply the torque command calculated according
to the velocity control command by the ratio of this
parameter and add the result to the torque command
resulting from the velocity control process.
1 13
Torque feed forward
filter
Set up the time constant of 1st delay filter which affects
the input of torque feed forward.
6 0
Analog torque feed
forward conversion
gain
Set the input gain of analog torque feed forward.
0 to 9 are invalid.
6 10
Function expansion
setup
Set up the function in unit of bit.
bit5 0: Analog torque feed forward is invalid.
1: Analog torque feed forward is Valid.
* bit 0 = LSB
Usage example of velocity feed forward
The velocity feed forward will become effective as the velocity feed forward gain is
gradually increased with the velocity feed forward filter set at approx. 50 (0.5 ms). The
positional deviation during operation at a constant velocity is reduced as shown in the
equation below in proportion to the value of velocity feed forward gain.
Positional deviation [unit of command] = command speed [unit of command/s] /
positional loop gain [1/s] × (100 - velocity feed forward gain [%]) / 100
Command speed
Motor speed
Positional deviation
Velocity feed forward gain
0[%]
50[%]
80[%]
Time
Positional deviation within the
constant speed range will
reduce as the velocity
forward gain is increased.