Steering Wheel Programs; Block Diagram; Backlash - Danfoss PVED-CLS User Manual

ENGINEERING TOMORROW

Steering wheel programs

When the PVED-CLS is in Off-road steering mode, one of the 5 different programs can be chosen which can be set with
some individual parameters for the steering ratio, and some parameters which are common for all 5 programs such as soft-
stop, anti-jerk etc. Furthermore, if the an OSPE/EHi-E system is being used and the OSP steering unit is specified as an
LSRM-type (see OSPE Steering valve, Technical information), then either Off-road reaction or Off-road non-reaction can
be chosen.
10.1

BLOCK DIAGRAM

Backlash/filter
10.2

BACKLASH

If the neutral springs in the OSP affect the SASAIID sensor readings when the driver releases the steering wheel and
hereby unintentionally operates the valve, a backlash region (P3570) can be applied to prevent it. The size of the backlash
region is normally set equal to the angle related to response. However, any set-value greater than zero leads to slower
steering responds. Therefore, to minimize these effects, the steering wheel, sensor shaft and underlying mechanics must
be designed as stiff as possible.
Since this parameter only affects changes in the set-point, stability problems in closed loop are not related to the set-value
of this parameter.
The value recommended by Danfoss, which is 0.5 Deg., i.e. P3570 set to 5, does not remove elasticity effects.
Important
Setting this value higher than the recommended value, could lead to slow steering response
Name
Backlash region P3570 U8
© Danfoss | August 2018
Fast steer and EFU Anti jerk
Description of parameter
Backlash limit to use in the backlash filter in the steering wheel control
dDeg algorithm
Resolution: 1dDeg = 0.1Deg
Soft-stop
Figure 40
Table 35
Control / no-control
decision
SVC
Flow to spool
position conversion
Range
OEM 0 200
AQ00000211 | 83
5