Improvement Of Protrusion At Quadrant Changeover - Mitsubishi Electric MDS-E Series Instruction Manual

MDS-E/EH Series Instruction Manual
5 Servo Adjustment

5.3.5 Improvement of Protrusion at Quadrant Changeover

The response delay (caused by dead band from friction, torsion, expansion/contraction, backlash, etc.) caused when the
machine advance direction reverses is compensated with the lost motion compensation (LMC compensation) function.
With this, the protrusions that occur at the quadrant changeover in the DBB measurement method, or the streaks that
occur when the quadrant changes during circular cutting can be improved.
Circle cutting path before compensation
[1] LMC compensation type 2
This is an obsolete compensation method. When performing new adjustment, use LMC compensation type 3.
[2] LMC compensation type 3
In addition to frictional torque influence, this type compensates torsion and expansion/contraction influences in the
machine system in which compensation amount is changed by travel speed. A mechanical system viscosity
coefficient setting further enhances the compensation accuracy even if the travel speed is changed. Adjustment
requires a machine roundness measurement.
[3] LMC compensation type 4
This is used in combination with LMC compensation type 3. Compensation is performed by monitoring path tracking
delay. Therefore, even if the machine friction amount has changed due to aged deterioration, the path tracking
delay is controlled so that it will be minimum.
POINT
1. LMC compensation performs adjustment while measuring the electrical end roundness waveform (encoder position FB).
Disable the NC side machine error compensation (pitch error compensation, relative position compensation, backlash
compensation). All machine error compensation can be disabled at once by setting SV113 to bit7.
2. After the compensation adjustment is completed, adjust the machine error compensation while measuring the machine
error compensation with DBB measurement method, etc.
Compensation
Cutting
direction
Circle cutting path after compensation
281
DBB: Double Ball Bar
IB-1501229-F