Maxsine EP3 AC Series, User Manual

Page: 72 / 246

Chapter 4 Running
62
4.2.4 Gains related to position control mode
Param
eter
Name Range
Default
value
Unit Usage
P009 1
st
gain of position loop 1 ～ 1000 40 1/s P
P013 2
nd
gain of position loop 1 ～ 1000 40 1/s P
P021
Feed forward gain of position
loop
0 ～ 100 0 % P
P022
Time-constant of feed forward
filter for position loop
0.20
～
50.00 1.00 ms P
According to the inner loop adjusts first and then the outer loop, the speed loop is included in
the position loop, therefore the rotation inertia ratio of load will be set first with suitable value.
Then, the gain and the integral time-constant of the speed loop are adjusted. At last, the gain of the
position loop is adjusted.
The following block diagram is the position regulator of the system. Increasing the gain of
position loop can get higher position loop bandwidth, but it is limited by the speed loop
bandwidth. Therefore, in order to increase the gain of the position loop must increase the
bandwidth of speed loop first.
The feed forward can reduce the lagging of phase in the position loop; also reduce the
position tracking error as well as shorter positioning time. The feed forward quantity increases,
the position tracking error reduces, but can cause the system unstable and overshoot if the feed
forward quantity is too large. If the electronic gear ratio is more than 10 it is also easy to make
noise. For normal application, the parameter P021 is set as 0%. If higher response and lower
tracking error are required, the P021 can be increased properly, but not in excess of 80%.
Meanwhile it may need to adjust the filter time constant (parameter P022) of the feed forward
branch.