QS2 Series Low-voltage Servo
Drive
53
6.3
Adjustment of PID Parameter
The servo system, adopted with PID regulation, is a feed-back system with
current loop, speed loop and position loop. The general principle followed is that:
the closer the loop is to the inner side, the higher the responsiveness should be.
Overshoot and vibration will occur without following the principle. Usually, the
current will not be modified as it ensures the responsiveness. Adjustment mainly
happened to position and speed loop.
Steps of servo debugging (position model): (1) set the speed loop integral to a
large value; (2) set the position loop gain to a small value and increase the
speed loop gain within a range that cause no vibration and abnormal sound;
(3) decrease the speed loop integral without causing vibration; (4) increase
position loop gain until vibration disappear; (5) properly modify the position
filter coefficient P18 to keep it running smoothly.
Recommended value
Item
Low rigidity
Medium rigidity
High rigidity
Position loop gain
50
80
100
Speed loop gain
100
200
300
Speed loop integral
500
500
500
Knowledge on rigidity of mechanical system:
The belt conveyor is of low rigidity, the low rigidity parameter can be applied;
Reducer drive ball screw is of medium rigidity, the medium rigidity parameter can be
applied;
Motor directly drive ball screw is of high rigidity, the high rigidity parameter can be
applied.
