IAI America XSEL-S - Manual (Page 410)

Chapter 6 Parameter
6.1
1 Servo
Adjustment
402
No. Phenomenon that
requires adjustment
How to adjust
4 Abnormal noise is
generated / Especially,
when stop and
operation in low speed
(less than 50mm/sec),
comparatively high
noise is generated.
� Input Driver Parameter No. 45 “Torque Filter Time Constant”. Try
to increase by 50 as a reference for the setting. If the setting is
too large, it may cause a loss of control system stability and lead
the generation of vibration.
[Important] Prior to Adjustment:
This phenomenon is likely to occur when the stiffness of the
mechanical components is not sufficient. The actuator itself may
also resonate if its stroke is over 600mm or it is belt-driven type.
Before having an adjustment, check if:
1) Check if the settings in Each Axis Parameter No. 60 “Position
Gain” and Driver Parameter No. 43 “Velocity Loop Gain” are
extreme. Check if Driver Parameter No. 44 “Velocity Loop
Integrated Gain” is set too low.
2) Check if the stiffness of the load is secured as much as
possible. Check if any looseness or play on the attachments.
3) Is the actuator body installed solidly with specified torque?
4) Check if there is any warpage on the actuator attachment base
surface.
Want to increase
tracking accuracy
Want to increase
velocity constancy
5
Want to increase
response sensibility
� Make the condition optimized with Parameter No. 60 “Position
Gain” and Driver Parameter No. 43 “Velocity Loop Gain”
adjusted by referring to the way to adjust stated in No. 1 to 3 in
the previous page.
[Reference]
Selection of an actuator (motor) is the most important element.
Servo is very sensitive to the amount of load inertia. For a servo
motor, if the moment of inertia on the load side (load inertia) is
too big to the moment of inertia of the motor itself (motor inertia),
the motor gets swung by the load, thus the control will become
unstable. Therefore, it is necessary to make the load inertia ratio
small in order to improve the accuracy in tracking, positioning,
velocity constancy or response sensibility.
It is recommended to have the lead on the ball screw for the
actuator as small as possible and have the actuator with one
rank higher motor capacity if accuracy is expected in tracking,
velocity constancy or response sensibility for such purpose as
painting.
The best way is to calculate the load inertia and select the mostly
suited actuator.
Start of movement is
slow due to large static
friction of load
Response for start and
stop is low due to large
inertia of load
6
Shorter takt time is
desired
� Set Each Axis Parameter No. 119 “FSG”.
As a reference for the setting, it should be from 10 to 50, and as
the setting gets high, the deviation gets small, thus the response
gets improved.
Vibration or noise may get generated if the setting is too high.
The setting is to be adjusted when improvement is required on
the responsibility only after an adjustment is made to Each Axis
Parameter No. 60 “Position Gain” and Driver Parameter No. 43
“Velocity Loop Gain”.