shifted 10 Xsp steps towards neutral compared to the previous Xspr_0, then Xpsr_1000 is shifted 10
Xsp steps as well. This maintains the transfer function slope.
The same procedure is applied to the left dead-band. When both open-loop dead-bands are calculated
and written, the changes are automatically committed to eeprom. The progress through the valve auto-
calibration procedure can be monitored on the CAN bus.
Operating the steering wheel during valve auto-calibration will immediately abort the valve auto-
calibration process. The PVED-CL will remain in calibration mode until power is cycled.
Suggested valve auto-calibration command values
The following table shows the suggested valve auto-calibration command values for the different valve
types. Other settings may be more appropriate. The optimum parameters for a particular vehicle must be
found by experimentation and testing.
Suggested valve auto-calibration command values
Command parameter
EH dynamic
EH static
OSPEH
EHPS
XspStartSearch
35
50
50
130
XspIncrementSize
5
5
5
5-10
YactDiffThreshold
20
20
20
20-30
TimeOutPeriod
500
500
500
500-1000
Changing TimeOutPeriod will affect the criterion where a flow is detected. Fix the TimeOutPeriod to 500
ms or 1000 ms, and adjust YactDiffThreshold until
a repeatable and robust performance is obtained.
Valve auto-calibration quick-guide
Valve auto-calibration procedure
1. Issue the start valve auto-calibration command from a MMI.
2. Monitor valve auto-calibration status messages. Optionally, enable status set 1 for detailed
monitoring of the analogue wheel angle sensor signal and the spool position set-point
3. Wait for status ‘auto-calibration completed’
See StartValveAutoCalibration and AutoCalibrationStatus in
PVED-CL Communication Protocol
,
11079551.
Parameter tuning order
1. Adjust XspCalibrationOffset. Use 65 as a starting reference.
2. Adjust and test valve auto-calibration command values (PVED-CL calibration mode)
Suggested valve auto-calibration command values
on page 29 for starting values.
3. Test and evaluate open-loop steering performance (operation mode)
4. Repeat step (1)2-3 until satisfactory results are obtained.
5. Adjust parameter ClosedLoopXspOffset. Use 65 as a starting reference.
6. Test and evaluate closed-loop steering performance (PVED-CL operation mode)
7. Repeat step 5-6 until satisfactory results are obtained.
The PVED-CL shall be powered-cycled after an auto-calibration before the new dead-band
parameters take effect.
The PVED-CL closed-loop performance can also be evaluated in calibration mode by issuing the
SetFlow command. To evaluate the smallest possible actuator speed, set ‘Requested Flow’ to ±1 and
apply ‘Closed-loop flow-to-spool-position scaling’. See SetFlow in
PVED-CL Communication Protocol
,
11079551.
Operation Manual
PVED-CL Controller for Electro-Hydraulic Steering, Version 1.38
Installation
©
Danfoss | May 2016
11025583 | AQ00000216en-US0302 | 29