Kinco FD5 Series - 6.6 Full closed loop mode

Kinco FD5 AC series servo driver user manual Chatper 7 Performance regulation
99
The velocity loop adjustment steps are as follows:
Step 1：Adjustment for Kvp
Increasing Kvp can improve the bandwidth of the velocity loop and make the velocity response ability faster. To calculate the Kvp,
please refer the following formula.
EncoderKtI
J
kvp
Max



B10853358080.1
25
π
Kt Motor torque constant，unit N.m/Arms*100
J Inertia，unit kg*m^2*10^6 B
B Velocity loop bandwidth unit: Hz
Imax MAX mortor current(6510.03)，unit: DEC
Encoder Resolution of the encoder
Because the -3 of Operation_mode has no acceleration and deceleration and does not participating the velocity loop control, the -3
mode and automatic flip mode can be used to run the motor when adjusting the velocity loop parameters. During the reciprocating
motion, the responsiveness of the servo can be monitored by collecting the speed step curve
If the Kvp too low, the bandwidth of the velocity loop and the position loop will not match, which will lead to oscillation. If the
Kvp is too high, it will cause the speed to overshoot and cause the speed loop to oscillate. In some rigid connection loads (such as
ball screw, rack and pinion, etc.) The Kvp should be as high as possible. By comparing the oscillograms under different Kvp, find
the optimal curve – the actuall speed curve should be tight follows the target command and does not have velocity oscillations.
Figure 7-4 Speed step curve after Kvp adjustment

Speed step curve：Curve that shows rise/fall changes.

The vibration and noise of the motor can be felt by hand touch and listening
Step 2
：
Adjustment for Kvi
Kvi is designed to eliminate static errors. It can strengthen the low frequency gain of the velocity loop, and a large Kvi can reduce
the response ability from low-frequency disturbance, thereby improving the anti-disturbance capability in low-frequency.
When Kvi is too small, The integral time will be long. The error adjustment will be slow, and it will take longer time to make the
system entering steady state. When the integral gain of the speed loop is too large, the error will appear and in severe cases, the
motor may oscillate. Kvi should be adjusted to the servo eliminating the error and enter a stable state efficiently.
Figure 7-5 Speed step curve after Kvi adjustment