Denso SMT7 - Page 86

Chapter 4 Configuring the Joint Parameters
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(9) Checking operations of the connected mechanism in full motion range and in
full speed range
Run the connected mechanism in the full motion range while changing the speed
gradually. If any abnormal noises or vibrations occur at some particular points, then
check whether the mechanism slides evenly.
If any abnormal noise occurs in some particular speed, tune the torque control filter
parameter again and check whether the abnormal noise decreases.
If tuning-up of the mechanism and torque control filter parameter cannot suppress
abnormal noises, then decrease the speed linear loop gain and speed integral loop
gain in the same proportion. (It is convenient to use the quick tuning function for the
speed control system gain described in the next item [ 4 ].)
If any vibration occurs in some particular speed, decrease the speed integral loop
gain, positioning loop gain, and/or positioning loop feed forward gain.
NOTE: Servomotors recommended earlier in this manual will issue torque ripple
4 times per rotation. The torque transmission mechanism may also issue torque
ripple specific times per rotation at its output shaft.
Therefore, the frequency of the torque ripple may vary according to the speed so
as to become equal to the natural frequency of the connected mechanism.
If vibrations are large in some specific speed, decrease the speed integral loop
gain, positioning loop gain and/or positioning loop feed forward gain as well as stated
above.
4.7.2.4 Quick tuning function for speed control system gain
As expressed in Formula 4.7-4, the ratio of the speed linear loop gain to speed
integral loop gain makes the integral speed loop gain time constant. For fine-tuning of
the speed control system gain, therefore, change the speed linear loop gain and
speed integral loop gain in the same proportion. This simultaneous and proportional
adjustment of those gains is "Quick tuning function for speed control system gain."
You may use this function with the teach pendant.
(1) Calling up the Quick Loop Gain Tuning screen using the teach pendant
Access: Top Screen―[F2 Arm]―[F6 Aux.]―[F7 Config.]―[F3 Jump To]
Select #59.
(2) Setting a value to "Gain Decreasing Ratio (J*)" for the joint (J*) to be tuned
The gain decreasing ratio is called Tuning Ratio. The controller automatically
modifies the current speed linear loop gain and speed integral loop gain by the
number of "Tuning Ratio" times.
The relationship between the value to be set and the tuning ratio is listed
below.
Set Value -5 -4 -3 -2 -1 0 1 2 3 4 5
Tuning Ratio 1.5 1.4 1.3 1.2 1.1 1 0.9 0.8 0.7 0.6 0.5