Example:
A value equal to 500 means that the driver needs to steer out 500/1000 of maximum flow before the slow
down-ramp is aborted. 500 again corresponds to a certain steering wheel RPM.
Typical values are 100-300 to have the abort down ramp possibility and to avoid unintentional abort of
the down ramp due to steering wheel activation due to vibrations. Setting the value to 1000 disables the
abort down ramp functionality.
Symbol
Index
Default
Value range
Sr
1y17
0
Must be set at 1
Lr
1y19
0
0 (linear) to 10 (max progressive)
Lf
1y20
0
0 to 10
Tro
1y21
1
1 to 1000 (ms)
Tfo
1y23
350
1 to 1000 (ms)
YsetFr
1y32
1000
0 to 1000 (1 unit = 0.1% of max. flow)
Tfr
1y33
100
1 to 1000 ms
Tfr shall be smaller than Tfo and less than 150 ms.
YAbortDownRamp
1y34
0
0 to 500 (1 unit = 0.1% of max. flow).
The default value will force an down-ramp abort at a slight reverse port flow request.
Typically YAbortDownRamp needs be increased to avoid unintentional down-ramp
aborts as this will infer a jerk on the driver.
Tra
1y35
1
1 to 1000 ms
Ramp-down time for canceled down-ramp
The discontinuities in the progressive characteristic are located at 50, 120 and 333 ([5.0;T at 25], [12,0;T at 50] and [33.3;T at 75] of max port flow
capacity)
Select Ramps with Ramp Times Related to Vehicle Speed
Often, slow ramps are not convenient at high speeds and results in difficulties driving precise and
straight. Including the vehicle speed information will allow the software to interpolate between
maximum and minimum ramp times as a function of vehicle speed.
Ramp time T(Ve) is determined by interpolating between Tro and Tfo as well as Tfo and Tfh as shown in
the figure below. The relation is equal for negative speeds.
Operation Manual
PVED-CL Controller for Electro-Hydraulic Steering, Version 1.38
Steering by Steering Wheel – Open Loop
46 |
©
Danfoss | May 2016
11025583 | AQ00000216en-US0302