A note on variable steering ratio:
In systems with an EHPS valve, the sensitivity settings yield equivalent steering ratio results on the
physical steering system.
In systems with an EH valve, the software does not take the parallel flow contribution from the OSP into
account. Unless compensated for, the resulting steering ratio on the physical steering system will be
lower than expected. To compensate, increase the sensitivity parameters and optionally limit the
maximum flow (Qm) to achieve the desired steering ratio for the used steering programs.
Select a Fixed Sensitivity
Vcap holds information about the actual valve capacity. This information is needed by the software to
achieve the desired sensitivity.
StrkVol holds information about the actual stroke volume (cylinder size). This information is needed by
the software to achieve the desired sensitivity.
Sse selects between a fixed steering sensitivity, variable to steering actuator position or vehicle speed.
Set Sse to 1 to select the fixed sensitivity
Sts0 defines the fixed steering ratio. This value shall be set large enough to provide sufficient directional
stability at all vehicle speeds. The default value is set to a commonly applied steering ratio.
Symbol
Index
Default
Value range
Vcap
706
25
5 to 120 (l/min)
StrkVol
707
600
100 to 8000 (cm3)
Sse
1y09
1
Must be set at 1
Sts0
1y10
400
20 to 1200
A steering ratio of 400 equals to 4.00 steering wheel turns to move the steering actuator from YL to YR (left to right end-lock position)
Select a Sensitivity with Relation to Actuator Position
A variable steering sensitivity related to actuator position is normally chosen for increased controllability
for straightforward driving (for e.g. material handling applications). The correlation between steering
wheel movements and the cylinder position is normally closely related to the mechanical geometry
between steering actuator and steered wheels of the individual vehicle.
P005 091E
Sts
(Yact)
saturates
100
200
300
400
500
0
340
360
380
400
420
St
eer
ing sensitivit
y S
ts
(Y
ac
t)
Yact - Steering actuator position: 1 unit = 0.1% of max position
700
800
900
600
1000
End lo
ck p
osition
min Sts = 20
max Sts = 1200
Sts1=400
Straight forward driving position
Sts0=400
The correlation is defined by two parameters. The steering sensitivity between two table coordinates is
found by linear interpolation. The functionality is symmetrical around neutral.
Vcap holds information about the actual valve capacity. This information is needed by the software to
achieve the desired sensitivity.
StrkVol holds information about the actual stroke volume (cylinder size). This information is needed by
the software to achieve the desired sensitivity.
Operation Manual
PVED-CL Controller for Electro-Hydraulic Steering, Version 1.38
Steering by Steering Wheel – Open Loop
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©
Danfoss | May 2016
11025583 | AQ00000216en-US0302