Mitsubishi Electric MR-JET User Manual page 89

Friction estimation function
[Pr. PF31]
Zero speed
Forward
rotation
Servo motor speed 0 r/min
Reverse
rotation
Zero speed
[Pr. PF31]
To perform friction estimation, the servo motor must be rotated at zero speed or higher, and operated for 150 s both in the high
and low-speed sections. The high speed indicates the section where the absolute value of the servo motor speed is equal to
or higher than [Pr. PF31 Machine diagnosis function - Friction judgment speed], whereas the low speed indicates the section
where the absolute value of the servo motor speed is less than [Pr. PF 31]. For the above operation pattern, when (a) + (c) is
150 s or more and (b) is 150 s or more, the friction in the forward rotation direction is estimated. The friction in the reverse
rotation direction is not estimated, even if time (d) is 150 s or more because the servo motor is not operated in the high-speed
section. In this case, decrease the setting value of [Pr. PF31] to perform friction estimation. When [Pr. PF31] is set to "0", the
threshold is 1/2 of the rated speed.
For the following operation pattern, it takes approximately 20 min. to complete friction estimation.
1/2 of rated speed
Forward
rotation
Servo motor speed 0 r/min
Reverse
rotation
1/2 of rated speed
The friction estimation function estimates the static friction both at forward rotation and reverse rotation, and the dynamic
friction (at rated speed) both at forward rotation and reverse rotation. To estimate these values, it is unnecessary to perform
to-and-fro positioning operation. When the servo motor is operated in acceleration/deceleration for forward rotation, only the
static friction and dynamic friction (at rated speed) at forward rotation can be estimated. When the servo motor is operated in
acceleration/deceleration for reverse rotation, only the static friction and dynamic friction (at rated speed) at reverse rotation
can be estimated.
The progress of the friction estimation can be checked by using MR Configurator2 or a controller.
When using MR Configurator2 to check the progress, open the machine diagnosis screen.
The progress can also be checked by the controller by using [Friction estimate status (Obj. 2C31h)].
Speed
(a) (b) (c)
Speed
3000 r/min
1 s 1 s 1 s 0.5 s
(d)
Time
Zero speed
1 s 1 s 1 s 0.5 s
Zero speed
-3000 r/min
Time
4 APPLICABLE FUNCTIONS
4.2 Machine diagnosis
4
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