Mitsubishi Electric MDS-E Series Instruction Manual page 309

MDS-E/EH Series Instruction Manual
5 Servo Adjustment
< Acceleration feed forward >
Vibration may occur at 10 to 20 Hz during acceleration/deceleration when a short time constant of 30 ms or less is
applied, and a position loop gain (PGN1) higher than the general standard value or SHG control is used. This is
because the torque is insufficient when starting or when starting deceleration, and can be resolved by setting the
acceleration rate feed forward gain (SV015: FFC). This is also effective in reducing the peak current (torque).
While measuring the current command waveform, increase FFC by 50 to 100 at a time and set the value where
vibration does not occur.
200
Current
command
100
(%)
0
0
Acceleration rate feed forward gain means that the speed loop gain during acceleration/deceleration is raised
equivalently. Thus, the torque (current command) required during acceleration/deceleration starts sooner. The
synchronization precision will improve if the FFC of the delayed side axis is raised between axes for which high-
precision synchronous control (such as synchronous tapping control and superimposition control).
【#2215】 SV015 FFC Acceleration rate feed forward gain
When a relative error in synchronous control is too large, set this parameter to the axis that is
delaying.
The standard setting is "0". The standard setting in the SHG control is "100".
To adjust a relative error in acceleration/deceleration, increase the value by 50 at a time.
---Setting range---
0 to 999 (%)
POINT
Overshooting occurs easily when a value above the standard value is set during SHG control.
IB-1501229-F
20
40 60 80
Time (ms)
No FFC setting
278
200
100
0
0 20
100
Time (ms)
With FFC setting
40 60 80
100