Attention Assist, Function - GF54.30-D-0009TSA

Model 907 

with code JW8 (Attention Assist) 

Shown on model 907 

Function requirements in general 

• Engine running or drive train operational.
• No undervoltage or overvoltage

The CDI control unit or the ME-SFI control unit sends the signal "Engine running" or "Drivetrain operational" via the powertrain CAN, the powertrain control unit and the suspension FlexRay to the ESP® control unit.

Attention Assist, general 

The attention assistance system is integrated in the ESP® 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 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 assistance system can be activated or deactivated in the "Assistance" menu in the "Attention Assist" menu level of the instrument cluster.

The instrument cluster sends the status of the attention assistance system via the user interface CAN, the electronic ignition lock (EZS) control unit and the suspension FlexRay to the ESP® control unit.

The driver can select the following operating modes:

• "Standard"
• "Sensitive"
• "Off"

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

In "Off" operating mode, the issuing of warnings is suppressed.

If "Standard" or "Sensitive" operating mode was selected before an ignition cycle, this mode is activated again after the next ignition cycle. 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. When "Off" mode is selected, this is indicated by a crossed-out coffee cup symbol in the multifunction display of the instrument cluster. When the attention assistance system is in "Standard" or "Sensitive" mode, the coffee cup symbol is not displayed.

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

• Attention level, circle or bar display (e.g. "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 v > 200 km/h)

At the start of the journey, the ESP® control unit uses an algorithm to determine the driver's individual warning threshold. This is the driving time and the time of day. The "Attention Level" display shows e.g. 5 bars. As indications of inattentiveness and fatigue increase, or when driving for long periods, the number of bars decreases.

If the warning threshold has been exceeded (only one bar is displayed): The multifunction display shows the warning message "ATTENTION ASSIST: Break!" and the driving time since the last break is displayed. The warning buzzer additionally issues a warning tone. The instrument cluster actuates the warning buzzer directly. The warning message can be acknowledged using the instrument cluster finger navigation pad (S163/1 s10) of the instrument cluster multifunction steering wheel button group.

A repeated warning message is issued at the earliest following expiry of t = 15 min.

If the warning threshold is exceeded, the nearest rest facilities are displayed to the driver in the Audio/COMAND display in addition to the warning message. Only premium parking places with a gas station and hospitality are taken into consideration.

The display of suitable rest facilities can be deactivated using the head unit multifunction steering wheel button group or the head unit control panel control unit. The system remains deactivated after the next ignition cycle.

The navigation system uses the GPS signals (GPS = global positioning system) and the navigation data to identify suitable rest facilities. 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

Time of day: 

The time of day is also defined by the current time.

The rain and light sensor registers the ambient brightness, evaluates it and sends information about the ambient brightness (dusk/dawn level) via the rain and light sensor LIN, the SAM control unit, the interior CAN, the electronic ignition lock (EZS) control unit and the suspension FlexRay to the ESP® control unit.

If there is a dusk/dawn transition at an implausible time of day, an entry is made in the diagnostic memory of the ESP® control unit.

Driving time: 

The driving time is determined by the ESP® control unit.

Vehicle speed: 

The vehicle speed is calculated by the ESP® control unit from the wheel speed.

Vehicle longitudinal/lateral acceleration and yaw rate: 

Information about the vehicle longitudinal and lateral acceleration and the yaw rate is registered by the acceleration sensor integrated in the Supplemental Restraint System (SRS) control unit. The SRS control unit sends the signals to the ESP® control unit via 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:
  • TEMPOMAT (with code MS1 (Cruise control) and with or without code ET4 (Active Distance Assist DISTRONIC))
  • Combination switch
  • Instrument cluster multifunction steering wheel button group or head unit multifunction steering wheel button group.
• The audio system is operated via the head unit (with code E1A (MBCONNECT-5) or with code E1C (Audio 25) or with code EJ2 (Audio 20) or with code EJ9 (COMAND Online)). The control interventions are received via the telematics CAN from the head unit control panel control unit.

The control interventions at the multifunction steering wheel button groups are read in by the steering wheel electronics and sent via the CAN LR to the steering column tube module (MRM) 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 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
• 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:

• 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, no warning is issued.

• No warning because of restrictions associated with the system limits:

  The driving behavior also cannot be evaluated in the active vehicle speed range (v = 60 to 200 km/h) if certain factors occur such as e. g. frequent lane changing, twisty roads, frequent control interventions, surface undulations, crosswinds or a dynamic driving style.

• 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 Models are particularly challenging for the attention assistance system, e.g. drivers with extremely smooth or extremely active steering behavior.

• 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.

• 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.

• 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.

• 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.

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