Operation Of Path Tracking Model Adaptive Control; Lost Motion Compensation Function; Restrictions On Lost Motion Compensation Function; Setting The Lost Motion Compensation Function - Mitsubishi Electric MELSERVO J5 Series User Manual

Operation of path tracking model adaptive control

In path tracking model adaptive control, changing the characteristics of model adaptive control enables the overshoot to be
suppressed when the servo motor stops. When [Pr. PA24.0 Vibration suppression mode selection] is set to any of "0"
(Standard mode), "1" (3 inertia mode), or "2" (Low response mode), short settling time in positioning is prioritized; when set to
"4" (Path tracking mode), drawing smooth paths is prioritized. Setting "4" (Path tracking mode) enables the overshoot to be
suppressed without a precise adjustment of [Pr. PB07 Model control gain].
11.2

Lost motion compensation function

The lost motion compensation function improves the response delay (caused by a non-sensitive band due to friction, twist,
expansion, and backlash) generated when the machine travel direction is reversed. With this function, protrusions at a
quadrant change and streaks at a quadrant change during circular cutting can be improved.
This function is effective when high path trackability is required, such as drawing an arc with an X-Y table.
Compensation
Travel direction
Trace before compensation

Restrictions on lost motion compensation function

The lost motion compensation is enabled in the position mode.

Setting the lost motion compensation function

Set the lost motion compensation with the following procedure.
Lost motion compensation function selection ([Pr. PE48])
Select the lost motion compensation function.
Servo parameter
PE48.0
PE48.1
Lost motion compensation amount ([Pr. PE44]/[Pr. PE45])
Set the same value for the lost motion compensation amount for both the direction from forward to reverse rotation and from
reverse to forward rotation. When the size of the protrusions differ depending on the travel direction, set the different
compensation amount for each travel direction. Set two times the usual value of the friction torque and adjust the value while
actually checking the protrusions.
Unbalanced torque offset ([Pr. PE47])
For a vertical axis, set an unbalanced torque offset by referring to the following.
Page 94 UNBALANCED TORQUE OFFSET
Trace after compensation
Description
Lost motion compensation type selection
0: Disabled
1: Enabled
Lost motion compensation non-sensitive band - Unit setting
0: 1 pulse unit
1: 1 kpulse unit
11 PATH CONTROL FUNCTION
11.2 Lost motion compensation function
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