Select The Control Principle; Apply Backlash; Set-Point Transfer Function - Danfoss pved-cl Operation Manual

Operation Manual
PVED-CL Controller for Electro-Hydraulic Steering, Version 1.38
Steering by Steering Wheel – Open Loop

Select the Control Principle

Symbol
Ri
0 means 0 degrees backlash, 200 means ~17 degrees backlash. Backlash applies in both steering directions; therefore the total backlash region is twice
the threshold.

Set-point Transfer Function

40 | © Danfoss | May 2016
Block diagram oped loop steering wheel steering
Sse , Sts0, Sts1, Sts2,Sts3, Sts4, Sts5, Vesm, StrkVol, Vcap
100 ms
Ve
Vehicle speed
10 ms
Yact
Actuator position
10 ms
Steering
10 ms 10 ms
X_stw wheel Backlash
Steering
angle/dt
wheel
angle
Ri
Cp is used to select Open loop control for steering wheel steering by setting parameter index 1y02 equal
to 0. Parameter selection values: Y selects the program and ranges from 0 and 9.

Apply Backlash

Ri If elasticity affects the sensor readings when the driver releases the steering wheel and hereby
unintentionally operates the valve, a backlash region (Ri) can be applied to prevent it. The size of the
backlash region is normally set equal to the angle related to elasticity.
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 as shown below must be designed as
stiff as possible.
Since this parameter only effects changes in the set point, stability problems in closed loop are not
related to the set-value of this parameter.
The default value does not remove elasticity effects.
Sensor
Steering wheel
Index
1y04
The transfer function provides two parameters to transform steering wheel positional information to port
flow. It main function is to create the flow request set-point from the steering wheel sensor.
Sr, Lr, Tro, Tfo, Lf,
Trh, Tfh, YsetFr, Tfr,
Steering
Cf, Off
TAbortDownRamp,
sensitivity
Yr, Yl
Tra, Verm
Transfer Ramp Soft
function function stop
100 ms
Qm,Lx
Yact
Ve - Vehicle
speed
Actuator
position
Default
0 to 5
Q
Port flow
command
10 ms
P005 206E
Value range
0 to 200
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