Attention Assist, Function - GF54.30-P-0009FG

Model 213 up to model year 2021 

Courtesy of MERCEDES-BENZ USA

Function requirements, general 

• Engine running or drive train operational:

  The CDI control unit or the ME-SFI [ME] control unit sends the "Engine running" or "Drive train operational" signal over the drive train CAN, drivetrain control unit and the suspension FlexRay to the Electronic Stability Program control unit.

Attention assistance system 

Attention Assistance is located in the Electronic Stability Program 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 in a vehicle speed range from 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.

The attention assistance system can be activated and deactivated via the operating level in the head unit. The following options are available for navigating in the control menu:

• Except code 446 (Touchpad only), the navigation is operated in the control menu using the Audio/COMMAND control panel. The Audio/COMMAND control panel sends the control signals via telematics CAN to the head unit.
• With code 446 (Touchpad only) or code 448 (Touchpad), the navigation can be operated in the control menu using the touchpad. The touchpad sends the operation signals over the telematics CAN to the head unit.
• With code 531 (COMMAND APS), the navigation can be operated in the control menu through voice control. The head unit evaluates the voice commands through the driver hands-free system microphone.
• The navigation in the control menu can also be operated using the head unit finger navigation pad and the "Back" button on the steering wheel. The steering wheel electronics read in the operation signals of the head unit finger navigation pad and the "Back" button and sends them over the steering LIN (up to model year 2019) or the steering wheel CAN (as of model year 2019), the steering column tube module control unit, suspension FlexRay, electronic ignition lock control unit and the user interface CAN to the head unit.
• With code 246 (Analog clock), the control menu can be called up with the Vehicle button in the upper control panel control unit. The upper control panel control unit reads in the status of the vehicle button and sends this over the LCP-LIN, Audio/COMMAND control panel (except code 446 (Touchpad only)) or Touchpad (with code 446 (Touchpad only)) and the telematics CAN to the head unit.

The head unit sends the status of the attention assistance system via the user interface CAN, electronic ignition lock control unit and chassis FlexRay to the Electronic Stability Program control unit.

The driver can select the following operating modes:

• Default
• Sensitive
• Off

The selected operating mode is displayed in the instrument cluster.

The head unit sends the status of the attention assistance system over the user interface CAN to the instrument cluster.

In "Sensitive" operating mode, the attention assistance system reacts more sensitively and issues warning messages sooner than in "Standard" operating mode.

In the "Off" operating mode, the emission of warnings is suppressed and no additional displays are output.

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.

The currently selected operating mode is stored in the Electronic Stability Program control unit. 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.

If the "Off" operating mode is selected, this is indicated by a coffee cup symbol and "OFF" in the instrument cluster. The icon of a coffee cup with "OFF" lettering is only displayed when the "engine is running" or the "drivetrain is operational". If the attention assistance system is in the "Standard" or "Sensitive" operating mode, the coffee cup symbol is not shown.

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)
• Passive attention assistance system (e.g. vehicle speed below 60 or over 200 km/h)

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

Shown on model 222, German system language 

Courtesy of MERCEDES-BENZ USA

The driver handling characteristics are also analyzed when the Attention Assist is switched off. If the Attention Assist is switched on during a journey, the entire journey from the start is taken into consideration.

At the start of the journey the Electronic Stability Program control unit uses an algorithm to determine the driver's individual warning threshold. This is the driving time and the time of day. In the "Attention Level" display mode, 5 bars (green (4 to 5 bars), yellow (2 to 3 bars), red (one bar)) are/is displayed. The Electronic Stability Program control unit sends the request to display the corresponding information over the chassis FlexRay, electronic ignition lock control unit and the 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 was exceeded, the Electronic Stability Program control unit sends a request to issue a warning over the chassis FlexRay, electronic ignition lock control unit and the user interface CAN to the instrument cluster and to the head unit, that then evaluate it.

The warning message "Attention Assist: Break!" then appears on the instrument cluster, and the driving time since the last break is displayed. A warning tone is also issued via the instrument cluster speaker. The instrument cluster directly actuates the instrument cluster speaker. The Electronic Stability Program control unit transmits the request to output a warning tone via suspension FlexRay, electronic ignition lock control unit and user interface CAN to the instrument cluster.

The warning message can be acknowledged using the instrument cluster finger navigation pad. The steering wheel electronics read in the status of the instrument cluster finger navigation pad directly and sends it over the steering LIN, steering column tube module control unit, suspension FlexRay, electronic ignition lock control unit and the user interface CAN to the instrument cluster. The steering column tube module control unit also sends the status of the instrument cluster finger navigation pad over the suspension FlexRay to the Electronic Stability Program control unit.

A warning message is issued again at the earliest after expiry of 15 minutes.

When driving, it is possible for the driver to experience not only a decrease in their attention level, but also an increase.

If the attention assistance system is unable to calculate an "Attention level" and unable to issue a warning, the instrument cluster shows the "System passive" message, e.g. if the vehicle speed is lower than 60 or higher than 200 km/h.

Vehicles with CODE 531 (COMMAND APS):

If the warning threshold is exceeded, the nearest rest facilities are also displayed to the driver in the Audio/COMMAND display along with the warning message. 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/COMMAND display. The system remains deactivated after the next ignition cycle.

The rest area icon is only displayed on freeway-type roads. The Electronic Stability Program control unit sends the request to issue a warning message over the chassis FlexRay, electronic ignition lock control unit and user interface CAN to the head unit. The head unit determines suitable stops using the GPS signals and the navigation data. The head unit actuates the Audio/COMMAND display via the telematics CAN and sends the corresponding video signals via the HSVL line.

Warning messages in instrument cluster, shown on model 213, GUI language: German 

Courtesy of MERCEDES-BENZ USA

The attention assistance system basically evaluates the following influencing factors:

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

Time of day: 

The time of day is also defined by the current time. The instrument cluster sends this to the Electronic Stability Program control unit via user interface CAN, electronic ignition lock control unit and suspension FlexRay. The received time is checked for plausibility by means of evaluating the ambient brightness. The ambient brightness is detected by the light sensor. The rain/light sensor with additional functions reads in the signals of the light sensor directly, evaluates them and sends information on the ambient brightness (dimness level) over the rain/light sensor-LIN, front SAM control unit, the interior CAN, electronic ignition lock control unit and the chassis FlexRay to the Electronic Stability Program control unit.

If there is a transition between dusk and dawn at an implausible time, an entry is made in the Electronic Stability Program control unit diagnostic memory.

Driving time: 

The driving time is determined by the Electronic Stability Program control unit.

Steering movements: 

Steering movements are recorded by the steering wheel angle sensor. The steering column tube module control unit reads in the steering wheel angle sensor signals directly and sends information on steering wheel angle and steering wheel velocity to the Electronic Stability Program control unit via suspension FlexRay.

Vehicle speed: 

The Electronic Stability Program control unit calculates the vehicle speed based on the wheel speed.

Vehicle longitudinal/lateral acceleration and yaw rate:  Information on vehicle longitudinal and lateral acceleration as well as yaw rate is recorded by the acceleration sensor integrated into the Supplemental Restraint System control unit. The supplemental restraint system control unit sends corresponding values over the vehicle dynamics CAN to the Electronic Stability Program control unit.

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:
  • Steering column adjustment switch
  • Combination switch
  • CRUISE CONTROL lever (up to model year 2019)
  • Instrument cluster multifunction steering wheel button group or head unit multifunction steering wheel button group
• Controls of left lower control panel
• Controls of right lower control panel

The head unit sends information on audio system control interventions to the Electronic Stability Program control unit over the user interface CAN, electronic ignition lock control unit and the chassis FlexRay. The steering column tube module control unit reads in control interventions on the steering column adjustment switch, the combination switch and the TEMPOMAT lever (up to model year 2019) directly and sends corresponding information over the suspension FlexRay to the Electronic Stability Program control unit. The steering wheel electronics read in control interventions at the multifunction steering wheel button groups directly and sends corresponding information over the steering LIN (up to model year 2019) or the steering wheel CAN (as of model year 2019), the steering column tube module control unit and the suspension FlexRay to the Electronic Stability Program control unit.

The left and right lower control panels send information on control interventions over the LCP-LIN, Audio/COMMAND control panel (except code 446 (Touchpad only)) or the touchpad (with code 446 (Touchpad only) or code 448 (Touchpad)), telematics CAN, head unit, user interface CAN, electronic ignition lock control unit and the suspension FlexRay to the Electronic Stability Program control unit. A warning is suppressed under the following conditions as no inferences about the attentiveness of the driver can be drawn from the driving behavior:

• With a driving time of less than 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 mainly below 80 or via 180 km/h
• Activated steering pilot (with code 23P (Driving assistance package Plus))
• Operation of audio system incl. telephony
• Incorrectly set time
• Active driving situations (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 (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 an active vehicle speed range (60 to 200 km/h) if certain factors exert an influence, e.g. 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 driver types are particularly challenging for the attention assistance system, 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 assistance system 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:

   The attention assistance system 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:

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

8. Influence of the steering pilot (with code 23P (Driving assistance package Plus)) on steering pattern evaluation:

   If the Steering Pilot is activated it is not possible to clearly determine whether steering movements are made by the driver or through the steering torques of the Steering Pilot.

9. Influence of "Sensitive" operating mode:

   Selecting the "Sensitive" operating mode tells the attention assistance system to operate in a more sensitive manner. The attention level determined by the attention assistance system is adapted accordingly and warnings are output earlier.

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