Steering Wheel Knob Position 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
Kp 108
Qm 1y27
Off 1y28
StrkVol 707

Steering Wheel Knob Position Control

© Danfoss | May 2016
Ql
1000
900
Example
Off=300
Qm=900
800
700
defaults
Off=100
600
Qm=1000
500
400
300
Ql = |Ff| * 1.33+Off
(Ff )
200
100
Off
0
0 100 200 300 400 500
Ff - Feedforward
Off Sets max port flow at zero feed forward. Setting the parameter equal to Qm disables the variable
proportional band.
The default value is set at 10% of max port flow, which is sufficient to counter act disturbances in steady
state and to control the steering actuator at low steering wheel speeds.
Qm Sets max port flow. It cuts-off the function and defines hereby the maximum speed of the steering
actuator to approach the set point position.
Kp This parameter is closely related to valve capacity, stroke volume and amplifies the error between set-
point and current position.
The optimum value for Kp is found when a non-lagging, accurate, non-oscillating steering actuation
without overshoot is achieved at:
•
Extreme low and high oil viscosities as specified in
•
Low and near max steering pressure when driving at low, high vehicle speed
and reversed gear. The default value fits to steering systems with a lock-to-
lock time of 2 seconds at max port flow.
Default Value range
50 0 to 200 (0.00 to 2.00% of port flow capacity per 0.1 % positional error)
1000 0 to 1000 (0.0 - 100.0% of max port flow)
100 0 to 1000 (0.0 - 100.0% of max port flow)
600 10 to 8000 ccm
In order to ensure convergence, check that variable Yact is increasing for positive values of port flow.
Open loop control can be used to check this. To retrieve this data, use StartStopStatus and request status
data set number 2. See PVED-CL Communication Protocol. The PVED-CL will return the status data with ~
40 ms intervals.
This function will continuously minimize the steering wheel drift that is build up and which results in
misalignment of the straight direction indication on the steering wheel and the actual driving direction.
The absolute steering wheel sensor position 0 defines the straight direction. Aligning the steering wheel
sensor with straight driving direction can be achieved by orienting the SASA sensor to output position 0
when the steering wheel and steering actuator are in straight position. Alternatively the SASA sensor
position 0 can be programmed after physical installation. Refer to CAN message Protocol in OSPE Steering
Valve, SASA Sensor, Technical Information, 11068682.
This function relates the absolute steering wheel position to the position of the steering actuator
saturates
(Ff )
Qm
600 700 800 900 1000
P005 219E
Technical Data on page 22.
11025583 | AQ00000216en-US0302 | 57