Tsino Dynatron CoolDrive Series, Руководство пользователя

Страница: 168 / 285

Adjustment
156
Feed-forward 7.9
Overview 7.9.1
CoolDrive Smart7's [feedforward] functions include [velocity feedforward] and [acceleration feedforward], as shown in the
figure below.
+
+ +
-
position
demand value
position
control
velocity
feedforward
+
-
Velocity
Control
+
+
acceleration
feedforward
torque
control
motor
encoder
velocity
feedback
position
feedback
In the position control mode, the required velocity control command can be calculated according to the position command,
which, as the [velocity feedforward] and together with the output of the position regulator, is the input of the velocity regulator.
Compared with feedback control, using [velocity feedforward] can better reduce the position error and improve the response.
In addition, the required torque command can also be calculated according to the velocity command, which, as the
[acceleration feedforward] and together with the output of the velocity regulator, is the input of the torque regulator,
improving the response of the velocity control system.
Velocity feedforward 7.9.2
The parameters for setting the [velocity feedforward] function are as follows.
Index Name Unit Setting range Default value effective Period
0x2162 Velocity Feedforward Gain 0.001 0-10000 1000 Immediately Y
0x2073
Velocity Feedforward Lowpass
Filter Cutoff Frequency
Hz 0-1000 1000 Immediately N

How to use
1. Set the [Velocity Feedforward Lowpass Filter Cutoff Frequency] to the default value of 1000, and gradually increase the
value of [Velocity Feedforward Gain] to make the velocity feedforward effective.
2. Observe the change of position error during the adjustment. Normally, the position error will gradually decrease along with
the increase of velocity feedforward gain. However, if the feedforward gain is too large, a huge overshoot will occur during
the acceleration and deceleration process.
3. In addition, when the update cycle of position command input is much longer than the control cycle of the drive, the use of
velocity feedforward may cause louder running noise. In this case, improvement can be made by decreasing the [Velocity
Feedforward Lowpass Filter Cutoff Frequency] or using a position command filter.