
B-65150E/04 4. SERVO FUNCTION DETAILS
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4.4 VIBRATION SUPPRESSION FUNCTION IN THE STOP
STATE
4.4.1 250 µsec Acceleration Feedback Function
(1) Overview
The acceleration feedback function is used to control velocity loop
oscillation by using motor speed feedback signal multiplied by the
acceleration feedback gain to compensate the torque command.
This function can stabilize unstable servo :
• When motor and machine have a spring coupling.
• When the external inertia is great compared to the motor inertia.
This is effective when vibration is about 50 to 150 Hz.
Fig 4.4.1 is a velocity loop block diagram that includes acceleration
feedback function.
Fig. 4.4.1 Velocity loop block diagram that includes acceleration feedback function
PK1V/s
PK2V Ka • s
A/(s + A) Kt 1/(Jm • s)
1/(J1 • s)
VCMD + + +
−−−
Torque
command filter
Torque
constant
Load inertia
Spring
coupling
Motor inertia
Speed feedback
PK1V: velocity loop integral gain
PK2V: velocity loop proportional gain
Ka : acceleration feedback gain