What Makes The Steering Wheel Drift; Eliminate Noise Due To Frequent Pressure Build-Up; Magnetic Valve Control - Danfoss pved-cl Operation Manual

Operation Manual
PVED-CL Controller for Electro-Hydraulic Steering, Version 1.38
Steering by Steering Wheel – Closed Loop
Symbol Index
Kd 1y31
Kc 1y30

Eliminate Noise due to Frequent Pressure Build-up

Symbol Index
Tclpout 117
Qth 118

Magnetic Valve Control

58 | © Danfoss | May 2016

What makes the steering wheel drift?

•
Flow & pressure saturation events that might occur during high steering wheel speeds combined
with low steering ratios.
•
Applying different steering ratios when driving into and out a curve. (Only when variable steering
ratio is active)
•
Activating joystick steering and re-activate steering wheel steering at a different actuator position
from where the joystick initially was activated.
Steering wheel drift is compensated by manipulation of the present steering sensitivity (Sts).
Kd Amplifies the steering wheel drift error. The resulting value represents a request in changing the
present steering sensitivity.
The default value disables the function.
Kc Limits the change in percentage of the present steering sensitivity.
The default value ensures that drift compensation is carried out beyond the notice of the driver.
Default
0
10
Eliminating noise is accomplished by stopping the controller to respond to minor deviations between set
point and current actuator position.
The spool inside the valve is set in neutral when the port flow command has been within a threshold
value (Qth) for a given time (Tclpout).
The spool is reactivated again when port flow command exceeds the threshold.
The default values mean that if a flow request from the controller is less than 5% of max. port flow, has
occurred for 3 seconds, the spool returns to neutral.
Tclpout Sets the time delay before the main spool is set in neutral.
Qth Sets the threshold value for port flow command when the controller is in steady state.
Default
3000
50
Magnetic valves off delay time Disables the magnetic valve bridge after a time specified in ms when the
flow request is 0, otherwise it remains enabled. This parameter is used when electrical energy
consumption by the solenoid bridge in the PVED must be reduced or to remove a steering control
conflict between the OSP and the PVED.
This applies to the EHPS valve, where a conflict may happen if the PVED is configured to be controlled
with either CAN or analogue steering devices but not with the steering wheel angle signal. In this
configuration the PVED- has no information about the steering wheel operation cannot resolve the
conflict.
The default value disables this functionality i.e. the magnetic valve bridge is enabled at all times. The
magnetic valve bridge is enabled when the PVED-CL receives a non-zero flow request.
Use this parameter to create EHPS type 1 configurations.
Value range
0 to 200
0 to 20 - > If Sts=400, Kc=10. Sts ranges from 360 to 440
Value range
1 to 30 000 (ms)
0 to 100 (0.0 to 10.0 % of max port flow)
11025583 | AQ00000216en-US0302