Siemens SINUMERIK 840D sl Function Manual page 413

5.6.2 Conventional friction compensation
Type of friction compensation
Conventional friction compensation is selected by entering the value 1 in machine data
MD32490 $MA_FRICT_COMP_MODE (friction compensation method).
Amplitude adaptation
In many cases, the injected amplitude of the friction compensation value does not remain
constant over the whole acceleration range. For example, for optimum compensation with
high accelerations, a smaller compensation value must be injected than for smaller
accelerations. For this reason, friction compensation with adapted injection amplitude can be
activated in cases where high accuracy is required (see diagram below). The function is
activated for specific axes with machine data
MD32510 $MA_FRICT_COMP_ADAPT_ENABLE = 1
(friction compensation adaptation active).
Figure 5-19
The adaptation characteristic is divided into four ranges (a different injection amplitude Δn is
applied in each range):
B1:
B2:
B3:
B4:
Extended Functions
Function Manual, 03/2009, 6FC5397-1BP10-4BA0
Typical curve for friction compensation with amplitude adaptation
for a < a
1
for a ≤ a ≤ a
1 2
for a < a < a
2 3
for a ≥ a
3
Friction compensation (quadrant error compensation)
Δn = Δn * a / a
max 1
Δn = Δn
max
Δn = Δn * (1 - (a - a
max
Δn = Δn
min
Compensations (K3)
) / (a - a ))
2 3 2
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