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10-9 Friction Torque Compensation Function
OMNUC G5-Series AC Servo Drives Users Manual (Built-in MECHATROLINK-II communications type)
10
Adj
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Func
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Operation Example
The friction torque compensation is applied to the input direction of the position command as
shown in the drawing below.
The Torque Command Value Offset (Pn607) reduces the variations of positioning operations
due to the movement directions when a certain amount of unbalanced load torque is always
applied to the motor at the vertical axis by setting the torque command.
The Forward Direction Torque Offset (Pn608) and Reverse Direction Torque Offset (Pn609)
are loads that require a large amount of dynamic friction torque due to the radial load, such as
the belt drive axis. By setting the friction torque for each rotation direction for all parameters,
you can reduce the deterioration and inconsistencies of positioning stabilization time due to
dynamic friction.
Precautions for Correct Use
You can use the unbalanced load compensation and the dynamic friction compensation together or
separately. Take note that the following use limit is applied upon CONTROL mode switching or
servo ON.
During torque control
The unbalanced load compensation and the dynamic friction compensation will be 0 regardless
of the parameter setting.
During speed control with Servo-OFF state
The load compensation is enabled based on Pn607 when the servo is turned OFF.The dynamic
friction compensation will be 0 regardless of the parameter setting.
When the servo is turned ON during position control or full closing control
The unbalanced load compensation and the dynamic friction compensation values is held until
the first position command is input.When the position command is input, the unbalanced load
compensation is updated based on Pn607. Also, based on the command direction, the dynamic
friction compensation value is updated according to parameters Pn608 or Pn609.
Command speed
Time
Motor
de-energized
Motor
de-energized
Motor power supply
Pn607
(Torque command
value offset)
Forward direction
Reverse direction
Pn608
(Forward direction torque offset)
Pn609
(Reverse direction
torque offset)