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

MODEL 166 up to model year 2016 

Function requirements, general 

• Terminal 15 ON

The status of circuit 15 is sent by the electronic ignition lock control unit over the chassis CAN 1 to the Electronic Stability Program control unit.

Attention Assist, general 

Attention Assistance is located in the Electronic Stability Program control unit. The attention assistance system detects the onset of fatigue or an increase in lack of attention (e.g. during long, monotonous journeys on freeways and long-distance roads) within a speed range of v = 80 to 180 km/h. If the attention assistance system detects appropriate signs of this, the driver is asked to take a break by issuing visual and acoustic warnings. To this end, the driving behavior of the driver is registered and evaluated using an algorithm (software).

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

If the attention assistance system is active a coffee cup symbol is shown in the multifunction display on the instrument cluster.

Attention Assist function switched on, shown on multifunction display up to 30.06.2012 

Function sequence for Attention Assist 

The Attention Assist can be switched on or off in the "Assist." menu in the "Attention Asst." menu level on the instrument cluster. The instrument cluster sends the corresponding status via chassis CAN 2, electronic ignition lock control unit and chassis CAN 1 to the Electronic Stability Program control unit.

If the attention assistance system function is switched on, steering patterns which could promote fatigue or inattentiveness are recorded in the following listed driving conditions:

• Monotonous journey (low longitudinal and lateral acceleration)
• No noteworthy external stimulation (e.g. surface undulations or crosswind)

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.

The algorithm classifies the following operating conditions as irrelevant:

• 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
• Active driving situation (e.g. lane change, change of speed)

At the start of the journey the algorithm determines an individual driver warning threshold.

The sensitivity of the algorithm adapts to match the driving time and time of day.

If the warning threshold has been exceeded, the Electronic Stability Program control unit sends a request over the chassis CAN 1, electronic ignition lock control unit and chassis CAN 2 to the instrument cluster to issue a warning message. The instrument cluster's multifunction display then shows the message "Attention Assist:

Break!". The warning buzzer integrated in the instrument cluster additionally issues a double four-tone signal. 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 O. K. button directly and transmits it via the steering LIN to the steering column tube module control unit. The steering column tube module control unit then sends the status via the chassis CAN 1 to the Electronic Stability Program control unit.

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

The algorithm of the attention assistance system mainly processes the following information:

• Time of day
• Driving time
• Vehicle longitudinal/lateral acceleration and yaw rate
• Steering movements
• Vehicle speed
• 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 chassis CAN 2, electronic ignition lock control unit and chassis CAN 1.

Based on the evaluation of ambient brightness by the rain/light sensor, the received time is checked for plausibility. The SAM control unit reads in the data from the rain/light sensor via roof LIN and transmits this via interior CAN, the electronic ignition lock control unit and chassis CAN 1 to the Electronic Stability Program control unit.

The Attention Assist analyzes the chronological development for 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 in the active range (speed between 80 and 180 km/h) is too short, a warning is not issued.

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.

Vehicle longitudinal/lateral acceleration and yaw rate:

The yaw rate, lateral and longitudinal acceleration sensor transmits information about vehicle longitudinal/lateral acceleration as well as yaw rate to the Electronic Stability Program control unit via the vehicle dynamics CAN.

Steering movements:

Steering movements are recorded by the steering wheel angle sensor.

The steering column tube module control unit reads in the data from the steering wheel angle sensor directly and sends them over the chassis CAN 1 to the Electronic Stability Program control unit.

Vehicle speed:

The Electronic Stability Program control unit calculates the vehicle speed from the wheel speeds. The wheel speeds are recorded by the rpm sensors and read in directly by the Electronic Stability Program control unit.

Control interventions:

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

• Radio or COMAND controller unit
• Cruise control lever
• Steering column adjustment switch or steering column adjustment and steering wheel heater switch
• Left multifunction steering wheel button group or right multifunction steering wheel button group

The control interventions at the radio buttons or the COMAND controller unit buttons are sent by the radio or COMAND controller unit via interior CAN, electronic ignition lock control unit and chassis CAN 1 to the Electronic Stability Program control unit.

Control interventions at the steering column adjuster, the combination switch on the CRUISE CONTROL lever and the multifunction steering wheel button groups are read in by the steering column tube module control unit and sent over the chassis CAN 1 to the Electronic Stability Program control unit.

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

Also valid is the following function information which can lead to possible function complaints at the customer's:

1. No warning issued because driving time too short in active vehicle speed range:
2. No warning because of restrictions associated with the limits of the function:

   In an active vehicle speed range (v = 80 to 180 km/h) the handling characteristics cannot be evaluated, when certain factors occur, e.g. frequent lane changing, twisty roads, frequent control interventions, surface undulations, crosswinds or a dynamic driving style. If these factors occur permanently the driving time in the active range is too short (see also Point 1).

3. Individual factors of driving situation or handling characteristics: Attention Assist determines a change in the handling characteristics. This change must not always be down to fatigue or increasing inattentiveness, it can also be the result of the steering ability characteristics. 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 assistance system reacts in accordance with the human biorhythm depending on the time (e.g. the midday 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 cannot only provide a warning in the event of fatigue, it can also provide a warning when a change in handling characteristics occurs, e.g. significant distraction.

   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:

   As well as fatigue or increasing inattentiveness, other factors can also significantly affect 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 road surface).

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