Attention assist, function - GF54.30-P-0009FLM

MODEL 212 as of model year 2014 

Function requirements, general 

• Engine running or drive train operational

The CDI control unit or the ME-SFI control unit sends the "engine running" or "drive train operational" signal via chassis CAN 1 to the Electronic Stability Program control unit or the regenerative braking system control unit.

Attention Assist, general 

The Attention Assist is integrated in the Electronic Stability Program control unit or the regenerative braking system control unit. By evaluating steering patterns any onset of driver fatigue (e.g. on long monotonous journeys on freeways and highways) can be detected. The steering patterns are evaluated within a vehicle speed range of v = 60 to 200 km/h. If any appropriate signs indicating fatigue or increasing lack of attention by the driver are recognized, the driver is prompted to take a break by means of visual and acoustic warnings.

Development of this software is based on experience gathered with test persons, whose different handling characteristics at night and day times were evaluated.

Function sequence for Attention Assist 

The Attention Assist can be activated or deactivated in the "Assist." menu in the "Attention Asst." menu level on the instrument cluster. The instrument cluster sends the status of the attention assistance system via chassis CAN 2, the front SAM control unit and chassis CAN 1 to the Electronic Stability Program control unit or the regenerative braking system control unit.

The driver can select the following operating modes:

• "Standard"
• "Sensitive"
• "OFF"

In "Sensitive" operating mode, the Attention Assist reacts more sensitively and issues warning messages sooner than in "Standard" operating mode.

The output of warnings is suppressed in "Off" operating mode.

"Last-turned-on mode":

If "Standard" or "Sensitive" operating mode was selected before an ignition cycle, this mode is activated again after the next ignition cycle. If the "Off" operating mode has been selected, this is indicated by a coffee cup symbol and also the text "OFF" in the multifunction display of the instrument cluster. If the Attention Assist is in "Standard" or "Sensitive" operating mode, the coffee cup symbol is not displayed. If the attention assistance system is switched off while driving (operating mode "Off"), the operating mode that was selected before switching off is automatically active after the next ignition cycle.

The driver can call up the following additional information via the "Info page" in the "Attention Asst." menu level of the instrument cluster:

• "Attention Level" (bar display, 5-stage)
• Driving time since last ignition cycle (in hours and minutes)
• Attention assistance system passive (e.g. vehicle speed v < 60 km/h or > 200 km/h)

If the attention assistance system is switched to passive, the "System passive" message is output on the multifunction display of the instrument cluster in addition to the driving time since the start of driving and the bar display.

The driver handling characteristics are also analyzed when the attention assistance system is switched to passive. If the attention assistance system is activated when driving, the entire journey from the start is taken into consideration.

At the start of the journey the Electronic Stability Program control unit or the regenerative braking system uses an algorithm to determine the driver's individual warning threshold. This is the driving time and the time of day. 5 bars (green, yellow, red) are shown in the "Attention Level" display. The Electronic Stability Program control unit or the regenerative braking system control unit sends the request to output the corresponding information via the chassis FlexRay, electronic ignition lock control unit and user interface CAN to the instrument cluster.

If the number of indicators for lack of attention or fatigue goes up or in the event of a longer driving distance, the number of bars goes down. If the warning threshold is exceeded (only one red bar is displayed), the Electronic Stability Program control unit or the regenerative braking system control unit sends the request to issue a warning message to the instrument cluster via chassis CAN 1, the front SAM control unit and chassis CAN 2. The signal is additionally sent by the Electronic Stability Program control unit or by the regenerative braking system control unit via chassis CAN 1, the front SAM control unit and interior CAN to the radio or to the COMAND controller unit.

The warning message "Attention Assist: Pause!" is then displayed on the multifunction display and the driving time since the last break is displayed. An acoustic warning is also issued via the warning buzzer. The instrument cluster actuates the warning buzzer directly.

The warning message can be acknowledged using the OK button in the left multifunction steering wheel button group. The steering wheel electronics reads in the status of the OK button directly and sends it to the instrument cluster via the steering LIN, the steering column tube module control unit, chassis CAN 1, the front SAM control unit and chassis CAN 2. The steering column tube module control unit also sends the status of the OK button via chassis CAN 1 to the Electronic Stability Program control unit or the regenerative braking system control unit.

A repeated warning message can only be issued following expiry of t = 15 minutes.

With the following vehicle variants, the nearest rest facilities are displayed in the Audio/COMAND display in addition to the warning indicator in the multifunction display if the warning threshold is exceeded:

• Vehicles with CODE 512 (COMAND APS incl. DVD changer)
• Vehicles with CODE 527 (COMAND APS with single DVD drive (with navigation))
• Vehicles with CODE 531 (COMAND APS)
• Vehicles with CODE 523 (MB Audio 20 radio) and CODE 509 (Navigation box)
• Vehicles with CODE 510 (Audio 20 with CD changer) and CODE 509 (Navigation box)
• Vehicles with CODE 522 (Audio 20 radio) and CODE 537 (SD card navigation)

Only premium parking places with a gas station and hospitality are taken into consideration. The display of suitable stops can be deactivated using the "Messages" menu on the Audio/COMAND display. The system remains deactivated after the next ignition cycle. The Electronic Stability Program control unit or the regenerative braking system control unit sends the request to issue a warning message via chassis CAN 1, the front SAM control unit and chassis CAN 2 to the radio or to the COMAND controller unit. The radio or the COMAND controller unit uses the GPS signals and the navigation data to determine suitable rest facilities.

The radio or the COMAND controller unit actuates the Audio/COMAND display via the telematics CAN and transmits the corresponding video signals via the LVDS line.

Essentially, the following influencing factors are evaluated:

• Time of day
• Driving time
• Steering movements
• Vehicle speed
• Vehicle longitudinal / lateral acceleration and yaw rate
• Control interventions
• Hands-off detection

Time of day:

The time of day is also defined by the current time. The instrument cluster sends this via chassis CAN 2, the front SAM control unit and chassis CAN 1 to the Electronic Stability Program control unit or the regenerative braking system control unit. The received time is checked for plausibility by means of evaluating the ambient brightness. The ambient brightness is sensed by the rain/light sensor. The front SAM control unit reads in the data from the rain/light sensor via the wiper/inside rearview mirror LIN and sends information to the ambient brightness (dusk/dawn level) via chassis CAN 1 to the Electronic Stability Program control unit or the regenerative braking system control unit.

In the event of a twilight transition implausible for the time of day, an entry is made in the diagnosis memory of the Electronic Stability Program control unit or regenerative braking system control unit.

Driving time:

The driving time is calculated by the Electronic Stability Program control unit or the regenerative braking system control unit.

Steering movements:

Steering movements are recorded by the steering angle sensor. The steering column tube module control unit reads in the signals from the steering angle sensor directly and sends the information on the steering angle via chassis CAN 1 to the Electronic Stability Program control unit or the regenerative braking system control unit.

Vehicle speed:

The Electronic Stability Program control unit or the regenerative braking system control unit calculates the vehicle speed from the wheel speeds.

Vehicle longitudinal / lateral acceleration and yaw rate:

Information about the vehicle's longitudinal and lateral acceleration and the yaw rate is recorded by the yaw rate sensor for lateral and longitudinal acceleration. The yaw rate sensor for lateral and longitudinal acceleration sends corresponding values to the Electronic Stability Program control unit or regenerative braking system control unit over the vehicle dynamics CAN.

Control interventions:

Control interventions at one of the following components disable the detection of steering patterns:

• Audio system controls (first-time operation is ignored, continuous operation is evaluated as distraction)
• Comfort function controls:
  • Cruise control lever
  • Steering column adjustment switch (except CODE 443 (Steering wheel heater)) or steering column adjustment and steering wheel heater switch (with CODE 443 (Steering wheel heater))
  • Combination switch
  • Left multifunction steering wheel button group or right multifunction steering wheel button group

The radio or the COMAND controller unit sends information on audio system control interventions to the Electronic Stability Program control unit or the regenerative braking system control unit via the interior CAN, front SAM control unit and chassis CAN 1.

The steering column tube module control unit sends information on control interventions at the cruise control lever, the steering column adjustment switch (except CODE 443 (Steering wheel heater)) or the steering column adjustment and steering wheel heater switch (with CODE 443 (Steering wheel heater)), the combination switch and the multifunction steering wheel button groups to the Electronic Stability Program control unit or the regenerative braking system control unit via chassis CAN 1.

The steering wheel electronics reads in the control signals on the multifunction steering wheel button groups directly and transmit them to the steering column tube module control unit over the steering LIN.

Hands-off detection:

The electrical power steering control unit sends the hands-off detection status via chassis CAN 2, the front SAM control unit and chassis CAN 1 to the Electronic Stability Program control unit or the regenerative braking system control unit. The Electronic Stability Program control unit or the regenerative braking system control unit uses this information to determine whether and at which time intervals the driver is making steering movements.

The Attention Assist only operates restrictedly under the following circumstances, and any warnings that are output are delayed:

• With a driving time of t > 30 min
• Poor road surface condition (e.g. surface undulations, pot holes)
• Strong crosswind
• Sporty driving style (e.g. high cornering speeds, high acceleration)
• Vehicle speed range predominantly below v = 80 km/h or above v = 180 km/h
• Activated Steer Assist (with CODE 266 (Steer Assist))
• Incorrectly set time
• Active driving situation (e.g. lane change, change of speed)

Also valid is the following function information which can lead to possible function complaints:

1. No warning issued because driving time too short in active vehicle speed range:

   The attention assistance system analyzes development of the handling characteristics. At the start of the journey the individual handling characteristic is classified. If the handling characteristic changes permanently a warning is issued. If the driving time within the active range (v_=_60_to_200_km/h) is too short, a warning is not issued.

2. No warning because of restrictions associated with the system limits:

   The handling characteristics cannot be evaluated in the active vehicle speed range (v_=_60_to_200 km/h) either if certain factors occur such as frequent lane changing, twisty roads, frequent control interventions, surface undulations, crosswinds or a dynamic driving style.

3. Personal driving behavior:

   The attention assistance system detects changes in driving behavior. These changes cannot always be explained as fatigue or increasing inattentiveness, rather they can also be caused by peculiarities in steering behavior. Certain types of driver present particular challenges for attention assistance systems, e.g. drivers with extremely smooth or extremely active steering behavior.

4. Influence of the time on the sensitivity of the Attention Assist:

   The Attention Assist reacts in accordance with the human bio-rhythm depending on the time (e.g. the mid-day low). These results are determined representatively, but they may also differ on an individual basis.

5. Influence of driving time on the sensitivity of the Attention Assist:

   As the length of driving time without a break increases, the sensitivity of the Attention Assist function also increases. The weighting of the driving time is based on surveys and correspond to the average fatigue characteristics.

6. Warning because of distraction or mild fatigue:

   Attention Assist can not only warn in the event of fatigue, it can also warn when a change in handling characteristics occurs, e.g. where the driver is greatly distracted. Therefore, a warning issued because of increasing inattentiveness is also to be deemed correct. The subjective fatigue sensitivity and the objective assessment variable determined by the Attention Assist are different.

7. Change in steering ability through other factors:

   Next to fatigue or increasing inattentiveness other factors can also significantly change the steering ability, and influence the objective assessment variables as determined by the Attention Assist, e.g. increasingly slippery road surface, worsening visibility, narrowing roadway, worsening roadway.

8. Influence of Steer Assist (with CODE 266 (Steer Assist)) on steering sample evaluation:

   If the steering assistance system is active, it is unclear whether steering movements have been made by the driver or by the Steer Assist.

	Attention Assist electrical function schematic		PE54.71-P-2054-97DAB
	Overview of system components for driver assistance systems		GF54.00-P-9998FLM