
B-65222EN/03 START-UP 4.PARAMETER SETTING
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4.1.2 Smooth Compensation for Linear Motor
(1) Overview
Smooth compensation for linear motors improves the smoothness in
feed of a linear motor by producing a sinusoidal compensation torque
with a cycle of 1/2, 1/4, or 1/6 of the pole-to-pole span produced by
servo software and by applying such a torque to the current command.
Compensation torque can be generated for each motor by setting gain
and phase for each components.
Torque command for correction
A
2
Sin (2
θ
+ P
2
)
+ A
4
Sin (4
θ
+ P
4
)
+ A
6
Sin (6
θ
+ P
6
)
Velocity loop
TCMD
+
Current loop
Activating phase angle
θ
Scale
Linear motor
+
(2) Series and editions of applicable servo software
Series 9096/A(01) and subsequent editions (Series 21i, Power Mate i)
Series 90B0/A(01) and subsequent editions (Series 15i, 16i, 18i, 21i )
(3) Setting parameters
1753 - Correction of two thrust ripples per magnetic pole pair
2130 - Correction gain (high-order 8 bits) Correction phase (low-order 8 bits)
1754 - Correction of four thrust ripples per magnetic pole pair
2131 - Correction gain (high-order 8 bits) Correction phase (low-order 8 bits)
1755 - Correction of six thrust ripples per magnetic pole pair
2132 - Correction gain (high-order 8 bits) Correction phase (low-order 8 bits)
The way thrust ripples occur varies from one motor (rather than
model) to another. Therefore, the correction parameters must be
determined specifically for each individual motor. This can be done
using "SD" (servo adjustment software) as a measurement tool.
The torque command ripples which occur at a specific position during
low-speed motor operation are assumed to be the ripples specific to
the motor at that position. A torque command having the same ripples
as these specific ripples is created to enable correction.
Follow the procedure described below to measure the activating phase
angle and torque command necessary to determine the correction
parameters.