
B-65150E/04 4. SERVO FUNCTION DETAILS
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(3) Adjustment items
If vibration occurs:
Check the position feedback setting (<3> in Sec. 4.17).
Check Vcmd (CH1), Tcmd (CH2 and CH4), and the speeds (CH5
and CH6) using the check board.
(a) A higher gear reduction ratio tends to produce more backlash,
such that unstable operation will result from the sub-axis running
between backlashes.
→ Enable the velocity feedback averaging function.
(No. 1952#2 = 1) Series 15
(No. 2008#2 = 1) Series 16
(b) The main axis and sub-axis vibrate at the same frequency (several
Hz to 30 or 40 Hz) as a result of the spring rigidity being low.
(The twist rigidity is proportional to the second power of the gear
reduction ratio, so that the frequency is probably a lower resonant
frequency.)
→ Enable damping compensation.
(See the adjustment procedure described in Subsec. 4.17.2.)
(No. 1952#2 = 1) Series 15
(No. 2008#2 = 1) Series 16
(c) The operation of a full-closed-loop system is unstable.
→ Check the position feedback setting (<3> in Sec. 4.17.) If the
parameters are set correctly, place the system in semi-closed loop
mode, then adjust the system to achieve stable operation.
Then, return the system to full-closed loop mode. If the operation
is still unstable, apply a function such as the dual position
feedback function.
(d) In the stop state, no tension is established between the main axis
and sub-axis.
→ Set a preload value of 0, and check the torque in the stop state.
Then, set a preload value greater than the stop-state torque.
(No. 1980) Series 15
(No. 2087) Series 16
(e) Position-dependent vibration occurs.
→ Change the feedrate to determine whether the vibration frequency
is constant or proportional to the feedrate.
If the vibration frequency is proportional to the feedrate,
position-dependent vibration is occurring. Check position-related
items such as the number of gear teeth.