Anti-Drift (Efu) - Danfoss PVED-CLS User Manual

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10.5 ANTI-DRIFT (EFU)

The anti-drift function is implemented for eliminating internal leakage errors and for having the steering wheel in the
(ccm per revolution) by adding an anti-drift correction portion to the calculated ideal ccm per revolution-output.
The anti-drift correction portion is calculated by looking at the difference, in degrees, measured at the steering wheel
and the actual position of the wheels. How large a percentage of the full flow, the PVED-
add, is defined by the following four points, Point A to Point D, where Point B and Point C are configurable.

Point A (0, 0)

Point B (P3568, P3569)

Point C (160, P3569)

Point D (0, 0)
50
45
40
35
30
25
20
15
10
5
Point A
0
0 10
The range is from 1° to 160° for P3568, in steps of 1°. For P3569 the range goes from 0% to 100% in steps of 1%.
The values recommended by Danfoss are P3568 set to 20 and P3569 set to 15 i.e. anti-drift will be enabled all the
time and 15% of the full flow will be added or deducted, depending on direction, to the calculated ideal ccm per
revolution-output, when the difference between the measured steering wheel position and the actual position of
the wheels is 20° -
linear interpolation, between Point C and the fixed point D, will determine the anti-drift correction portion.
Furthermore, anti-drift function will also improve consistency in lock-to-lock on steering wheel.
Important
If anti-drift is not needed, the operator can disable the function by setting P3569 to 0.
STW - Anti-drift (EFU)
Point B
20 30 40 50 60 70
|Steering wheel angle difference [degrees]|
80 90 100 110 120 130 140 150 160 170 180
Figure 31
determine the correct output flow
-drift algorithm will
Point C
Point D