Zapi EPS-AC0 SWs&ENC User Manual page 72

steered wheel angle in the direction where FEEDBACK ENC is lower than 2.5
V. It is used in closed loop application only (Twin pot) and it is a scaling factor
between the SET POINT POT reading and the FEEDBACK ENC reading.
By increasing this parameter, the maximum steered wheel angle increases too.
17) NUMBNESS
(Twin Pot version only). This parameter reduces the steering sensitivity close to
the straight-ahead direction.
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Intermediate reductions of sensitivity are applied for intermediate settings. The
steering sensitivity increases in a proportional relationship with the increased
steering wheel angle. To be more precise, by increasing the NUMBNESS
setting, no sensitivity modification is applied when the steering wheel is close to
be straight, but higher sensitivity is applied when the steering wheel is angled.
As consequence, when changing the NUMBNESS value, it is necessary to re-
adjust the maximum angle limitations with the settings 1ST ANGLE COARSE
(and FINE) and 2ND ANGLE COARSE (and FINE).
18) LAG FB REGULAT
Level 0 to 9. It is used to set the integral (lag) contribution to a PID algorithm for
Twin pot and AUTC functions. The integral contribution is applied to the
FEEDBACK ENC value only. It works like a low pass filter to get smooth the
pursuing next to the commanded position. The derivative (lead) contribution
generates dither that is possible to reduce by increasing this adjustment.
Obviously lag and lead regulations influence the stability of the closed loop and
so different setting must be empirically tried to avoid oscillations.
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19) LEAD FB REGULAT
Level 0 to 9. It is used to set the derivative (lead) contribution to a PID algorithm
for Twin pot and AUTC functions. The derivative contribution is applied to the
FEEDBACK ENC value only. High LEAD FB REGULAT value brakes the
steering motor in advance respect to the commanded position so avoiding the
overshooting of the commanded position. On the other side generates damping
and dither, close to the commanded position. Obviously lag and lead regulations
influence the stability of the closed loop and so different setting must be
empirically tried to avoid oscillations.
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LEVEL 0: No reduction in the steer sensitivity with the steering angle.
LEVEL 9: Steering 4.5 less sensitive in the straight ahead direction.
LEVEL 0: lowest lag contribution (high cut off frequency low pass filter).
LEVEL 9: highest lag contribution (low cut off frequency low pass filter).
LEVEL 0: lowest lead contribution (overshooting is favourite).
LEVEL 9: highest lead contribution (damping is favourite).
AEMZP0EA - EPS-AC0 SWs&ENC - User Manual