Steering By High Priority Steering Device - Closed Loop; Functionality Tree; Tracking - Danfoss pved-cl Operation Manual

Operation Manual
PVED-CL Controller for Electro-Hydraulic Steering, Version 1.38
Steering by High Priority Steering Device – Closed Loop
Steering by High Priority Steering Device – Closed Loop

Functionality Tree

72 | © Danfoss | May 2016
EHPS Type 2 Automatic Steering Diagram
Joystick or mini wheel
High
priority
OSP
OSP
PVE
EHPS valve
PVE EHPS Valve
Automatic steering
Vehicle speed
The tree below illustrates the functionality available in the PVED for steering by a potentiometer device
or by joystick or by mini wheel with speed output. The manufacturing default functionality is found by
following the red line. It can of course be modified by following the instructions in this chapter. The
switches in the tree are used to select the functionality required. In case different functionalities are
required, the EHPS software provides 5 programs from which the driver can select when the system is
fully operative. For steering by a device without spring return the PVED provides closed loop position
control. The steering signal is monotonic and represents the angle of the physical device. These devices
are normally friction held to prevent unintentionally steering due to machine vibrations. Use this mode
for implementation of proprietary auto-guidance applications i.e. auto-guidance applications that do not
conform to the ISO standardized auto-guidance messages. See
*
Switches Cp Sse
Open loop
Cp=0
No signal (0)
AD1 (1)
AD2 (2) Closed loop
Cp=255
CAN (4)
default
* Sensitivity means: Port flow amplification

Tracking

For safety reasons, a tracking function ensures bump-less transition on control loop initialization. It forces
the user initially to operate the potentiometer knob into a position that matches zero deviation between
set point and current steering actuator position or by sweeping through it. While tracking, the
commanded port flow is limited at zero.
Steering angle sensor
Q
Q
Steering
Steering
cylinder
cylinder
Position sensor
P005 225E
Open loop, fixed sensitivity, with fixed ramp
Sr
times
Fixed Sr=1
Open loop, fixed sensitivity, with ramp times
Var Sr=2
related to vehicle speed
No Sr=0
Open loop, fixed sensitivity, with no
ramps applied
Fixed
Sse=1
Open loop, sensitivity related to steering actuator
position, with fixed ramp times
Related to
Fixed Sr=1
position of
Open loop, sensitivity related to steering actuator
steering
Var Sr=2
position, with ramp times related to vehicle speed
actuator
No Sr=0
Sse = 2
Open loop, sensitivity related to steering actuator
position, with no ramps applied
Related to
vehicle speed
Sse=3
Open loop, sensitivity related to vehicle speed, with
fixed ramp times
Fixed Sr=1
Open loop, sensitivity related to vehicle speed, with
Var Sr=2
ramp times related to vehicle speed
No Sr=0
Open loop, sensitivity related to vehicle speed,
with no ramps applied
Closed loop, Fixed sensitivity, no ramps possible
Auto-steering on page 94.
Program number: Y
4
3
2
1
Y=0
P005 089E
11025583 | AQ00000216en-US0302