Attention Assist, Function - GF54.30-P-0009FQ
MODEL 218
up to year 2015
Up to 28.02.2013
As of 01.03.2013
Function requirements, general
- Terminal 15 ON
The status of circuit 15 is sent by the electronic ignition lock control unit to the Electronic Stability Program control unit via the chassis CAN (up to 28.02.2013) or chassis CAN 1 (as of 01.03.2013).
Attention Assist, general
The attention assistance system function is integrated into 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 of v = 80 to 180 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 function can be switched on or off in the "Assist." menu in the "Attention Assist." menu level on the instrument cluster. On vehicles up to 28.02.2013, the instrument cluster sends the status of the function to the Electronic Stability Program control unit via the chassis CAN. On vehicles as of 01.03.2013, the instrument cluster sends the status of the function to the Electronic Stability Program control unit via chassis CAN 2, the front SAM control unit and chassis CAN 1. If the attention assistance system function is active, a coffee cup symbol is shown in the multifunction display of the instrument cluster.
The driver handling characteristics are also analyzed when the function is switched off. When the function is switched on the handling characteristics can be considered right from the start.
Attention assistance system function ON
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.
If the warning threshold has been exceeded, on vehicles up to 28.02.2013 the Electronic Stability Program control unit sends the request to issue a warning message to the instrument cluster via the chassis CAN. On vehicles as of 01.03.2013, the Electronic Stability Program 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 "Attention Assist: Pause!" warning message then appears on the multifunction display of the instrument cluster. The warning buzzer integrated in the instrument cluster additionally issues a double four-tone signal. This warning message can be acknowledged using the OK button in the left multifunction steering wheel button group. The steering wheel electronics read in the signals from the OK button directly and send them to the Electronic Stability Program control unit via the steering LIN, the steering column tube module control unit and chassis CAN (up to 28.02.2013) or chassis CAN 1 (as of 01.03.2013).
A repeated warning message can only be issued following expiry of t = 15 minutes.
The following influencing factors are evaluated to implement the Attention Assist function:
- 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. On vehicles up to 28.02.2013, the instrument cluster sends this to the Electronic Stability Program control unit via the chassis CAN. On vehicles as of 01.03.2013, the instrument cluster sends the current time to the Electronic Stability Program control unit via chassis CAN 2, the front SAM control unit and chassis CAN 1. The received time is referenced to 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 mirror LIN and sends this data to the Electronic Stability Program control unit via the chassis CAN (up to 28.02.2013) or chassis CAN 1 (as of 01.03.2013).
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 angle sensor. The steering column tube module control unit reads in the signals from the steering angle sensor directly and sends them to the Electronic Stability Program control unit via the chassis CAN (up to 28.02.2013) or chassis CAN 1 (as of 01.03.2013).
Vehicle speed:
The Electronic Stability Program control unit calculates the vehicle speed from the wheel speeds. The wheel speeds are detected by the RPM sensors. The Electronic Stability Program control unit directly reads in the signals from the RPM sensors.
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.
Control interventions:
Control interventions at one of the following components the detection of steering patterns is suppressed:
- Radio (with code 523 (Audio 20 CD) or code 510 (Audio 20 CD with 6-disk CD-changer)) or Radio with Auto Pilot System (with code 525 (MB Audio 50 APS radio) or code 511 (Audio 50 APS incl. DVD changer)) or COMMAND controller unit (with code 512 (COMMAND APS incl. DVD changer), code 526 (COMMAND with single DVD drive (without navigation)), code 527 (COMMAND APS with single DVD drive (with navigation)) or code 528 (COMMAND incl. DVD changer))
- Combination switch
- Cruise control lever
- Steering column adjustment switch (with code 275 (Memory package), without code 443 (Steering wheel heater)) or Steering column adjustment switch and steering wheel heater (with code 275 (Memory package) and code 443 (Steering wheel heater))
- Multifunction steering wheel button group
The radio or COMMAND controller unit sends information on control interventions at the audio system to the Electronic Stability Program control unit via the interior CAN, front SAM control unit and chassis CAN (up to 28.02.2013) or chassis CAN 1 (as of 01.03.2013).
The steering column tube module control unit reads in the control interventions at the steering column adjustment switch, the combination switch, the cruise control lever and the multifunction steering wheel button groups and sends them to the Electronic Stability Program control unit via the chassis CAN (up to 28.02.2013) or chassis CAN 1 (as of 01.03.2013).
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.
A warning is suppressed under the following conditions as no inferences about the attentiveness of the driver can be drawn from the driving behavior:
- 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)
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 function analyzes the development of driving behavior over time. 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.
- No warning in the case of external influences which affect driving behavior:
Driving behavior is not evaluated when no inferences about the attentiveness of the driver can be drawn (e.g. frequent lane change, twisty roads, frequent control interventions, surface undulations, crosswind or dynamic driving style).
- Personal driving behavior:
The Attention Assist function 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 present specific challenges for the Attention Assist function, e.g. drivers with extremely smooth or extremely active steering behavior.
- Influence of time on sensitivity of function:
The function reacts differently depending on the time in accordance with the human biorhythm (e.g. takes into consideration the mid-day low). This has been determined on a representative basis, but can of course vary from person to person.
- Influence of driving time on sensitivity of function:
In the case of a long period of driving without a break, the sensitivity of the Attention Assist function 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 Assist function 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 level of fatigue sensitivity and the assessment values determined by the attention assistance system function may differ.
- Change in steering ability through other factors:
Next to fatigue or increasing inattentiveness other factors can significantly change the steering ability, and influence the objective assessment variables as determined by the system, e.g. increasingly slippery road surface, worsening visibility, narrowing roadway, worsening roadway.
| Attention Assist electrical function schematic | PE54.71-P-2054-97XAA | ||
| Overview of system components for driver assistance systems | GF54.00-P-9998FQ |