Straight Ahead Steering Numbness; Overshooting And Damping Avoiding; Special Debugging And Troubleshooting System - Zapi EPS-AC0 SWs&ENC User Manual

has a drift with a released steering wheel. To enable this function, turn RECOVERY
AT REST to On and recycle the key (see 11.4.1.10). This alignment at the rest
position is handled closed loop.

12.4 Straight ahead steering numbness

In closed loop applicant (twin pot at the handle bar) It is possible to reduce the
steering sensitivity while the steered wheel is close to be straight ahead by using the
NUMBNESS setting in the PARAMETERS CHANGE menu. Increasing the
NUMBNESS parameter gets the steering less responsive when the truck is driving
next to the straight ahead direction (i.e. a certain increment of the steering wheel
angle gets a smaller increment of the steered wheel angle when the truck is driving
straight ahead than when it is angled).
Higher NUMBNESS setting results in higher numbness of the steering at low
steered wheel angle. NUMBNESS to Level 0 results in a linear relationship between
the command and the steered wheel angle (no sensitivity reduction in straight
ahead).

12.5 Overshooting and Damping avoiding

To optimize the steer performance in closed loop application, the following simple
test should be tried.
Turn the tiller in a shot from a limiting position to the straight ahead direction. The
steered wheel is expected to turn from the limiting position to the straight head at full
steering motor speed. Then it must suddenly stop in the straight ahead direction
without overshooting or damping (overshooting means the steered wheel temporary
overtakes the commanded position; damping means the steered wheel slows down
in advance respect to the commanded position).
Actions to neutralize overshooting are:
1) Increase parameter change LEAD FB REGULAT
2) Reduce parameter change KP or POS ACCURACY. This action reduces also
the accuracy of the pursuing at the commanded position
Actions to neutralize damping are:
1) Reduce parameter change LEAD FB REGULAT
2) Increase parameter change KP or POS ACCURACY. This action increases also
the accuracy of the pursuing at the commanded position

12.6 Special Debugging and Troubleshooting system

Eps-ac0 provides a special adjustment (DEBUG OUTPUT) to facilitate the
troubleshooting. Some alarms may be due to many different causes that are difficult
to catch. In particular, the alarms in which the steered wheel does not pursuit the
commanded positions (FB SENS LOCKED, MOTOR LOCKED, POSITION ERROR)
may be due to a mechanical fault or to a failed sensor or to a problem in the motor.
It is difficult to find the root for the problem in the short time before the alarm occurs.
For this reason the eps-ac0 provides a method to temporary inhibit these alarms. It
is just enough to set the special adjustment DEBUG OUTPUT to Level 11. Then the
steering system works without these alarms and the service can take longer time to
analyze the system and to catch the fault.
AEMZP0EA - EPS-AC0 SWs&ENC - User Manual Page - 81/95