Attention Assist Function - GF54.30-S-0016TRF
Model 447
With Code JW8 (Attention Assist)
With Code XM0 (Facelift)
Illustration shows MODEL 447.8
Shown on model 447.6/7
Function requirements in general
- Engine running or drive train operational.
The CDI control unit or the ME-SFI control unit sends the "Engine running" or "Drivetrain operational" signal to the Electronic Stability Program (ESP) control unit.
Attention assistance system, general
The attention assistance system is integrated in the Electronic Stability Program (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 the attention assistance system
Model 447.8:
- Attention Assist can be activated or deactivated via the menu Assistance → Attention Assist of the instrument cluster.
- The instrument cluster (IC) control unit sends the status of the attention assistance system to the Electronic Stability Program (ESP) control unit via the user interface CAN, gateway for the user interface CAN, and the chassis CAN.
Model 447.6/7:
- The attention assistance system can be activated or deactivated via the menu Assist. → Attention Assist of the instrument cluster.
- The instrument cluster (IC) control unit sends the status of the attention assistance system via the chassis CAN to the Electronic Stability Program (ESP) control unit.
The driver can select the following settings:
- "Standard"
- "Sensitive"
- "Off"
In the "Sensitive" setting, the attention assistance system reacts more sensitively and issues warning messages sooner than in the "Standard" setting.
In the "Off" setting, the issuing of warnings is suppressed. Model 447.8, message in multifunction display: "OFF".
"Last-turned-on mode":
If the "Standard" or "Sensitive" setting 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 (setting "Off"), the setting that was selected before switching off is automatically active after the next ignition cycle.
Model 447.8:
- If the "Off" setting has been selected, this is indicated by a crossed-out coffee cup symbol in the display of the instrument cluster (IC) control unit. If the attention assistance system is in the "Standard" or "Sensitive" setting, the coffee cup symbol is not displayed.
Model 447.6/7 without code JK3 (instrument cluster with pixel matrix display):
- If setting "Off" is selected, this is displayed by the attention assistance system indicator lamp (A1/1e63). If the attention assistance system is in the "Standard" or "Sensitive" setting, the attention assistance system indicator lamp is off.
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" (model 447.8, 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)
If the attention assistance system is switched to passive, the "System passive" message is shown on the instrument cluster display as well as the driving time since the start of driving and the bar display.
Illustration shows MODEL 447.8
The driver driving behavior is 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 (ESP) control unit uses an algorithm to determine the driver's individual warning threshold. This is the driving time and the time of day.
On model 447.8, the "Attention level" display shows 5 bars (green, yellow, red). With increasing signs of inattentiveness and fatigue or in the case of a long driving distance, the number of bars goes down and the color of the remaining bars displayed changes from green to yellow and then to red.
If the warning threshold has been exceeded (only one red bar is displayed), the following request is sent:
- Model 447.8:
- The Electronic Stability Program (ESP) control unit sends the request to output a warning via the chassis CAN, gateway for user interface CAN, and user interface CAN to the instrument cluster (IC) control unit and to the radio (Audio/COMAND), which evaluate this.
- The warning message "Attention Assist: Pause!" is then displayed on the display and the driving time since the last break is also displayed. A warning tone is also issued via the instrument cluster speaker. The instrument cluster (IC) control unit directly actuates the instrument cluster speaker.
- Model 447.6/7:
- The Electronic Stability Program (ESP) control unit sends the request to output a warning via the chassis CAN to the instrument cluster (IC) control unit.
- The instrument cluster (IC) control unit then displays the warning message "Attention Assist: Pause!" or "Attent. Asst. Pause!" and the driving time since the last break. A warning tone is also issued via the instrument cluster speaker. The instrument cluster (IC) control unit directly actuates the instrument cluster speaker.
The warning message can be acknowledged with the button "O. K." on the left multifunction steering wheel button group (with code CL4 (multifunction steering wheel with trip computer)). The steering column tube module control unit reads in the status of the "O. K." button via the steering LIN from the steering wheel electronics and transmits this to the instrument cluster (IC) control unit. The steering column tube module control unit also sends the status of the "O. K." button via the chassis CAN to the Electronic Stability Program (ESP) control unit.
A warning message is issued again at the earliest after t = 15 min have elapsed.
Model 447.8:
- If the warning threshold is exceeded, the nearest rest facilities are displayed to the driver in the Audio/COMAND display (A40/8) 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 "Messages" menu in the Audio/COMAND display control unit. The system remains deactivated after the next ignition cycle.
The Electronic Stability Program (ESP) control unit sends the request to issue a warning message to the radio (Audio/COMAND).
The radio (Audio/COMAND) uses the signals from the global navigation system (GPS) and the navigation data to determine suitable rest facilities. The radio (Audio/COMAND) actuates the Audio/COMAND display control unit via the telematics CAN and transmits the corresponding video signals via Low Voltage Differential Signaling.
Display warning message, model 447.8
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 instrument cluster (IC) control unit transmits the current time to the Electronic Stability Program (ESP) control unit. The received time is checked for plausibility by means of evaluating the ambient brightness.
The ambient brightness is recorded by the humidity sensor/light sensor/rain sensor or by the rain and light sensor with additional functions.
The humidity sensor/light sensor/rain sensor or the rain and light sensor with additional functions evaluates this and sends information about the ambient brightness (dusk/dawn level) via the roof LIN, the signal acquisition and actuation module (SAM) control unit, the interior CAN, the electronic ignition lock control unit and the chassis CAN to the Electronic Stability Program (ESP) control unit.
If there is a transition between dusk and dawn at an implausible time, an entry is made in the diagnostic memory of the Electronic Stability Program (ESP) control unit.
Driving time
The driving time is determined by the Electronic Stability Program (ESP) control unit.
Steering movements
Steering movements are recorded by the steering angle sensor. The steering column tube module (MRM) control unit reads in the signals from the steering angle sensor directly and transmits information about the steering wheel angle and the steering wheel velocity to the Electronic Stability Program (ESP) control unit via the chassis CAN.
Vehicle speed
The vehicle speed is calculated by the Electronic Stability Program (ESP) control unit using 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 in the Electronic Stability Program (ESP) 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:
- Cruise control lever
- Combination switch
- Left multifunction steering wheel button group or right multifunction steering wheel button group
Model 447.8:
- The audio system is operated using the central operating unit (COU) control unit. The control interventions at the central operating unit (COU) control unit are received by the radio (Audio/COMAND) via the telematics CAN. The radio (Audio/COMAND) sends information about the control interventions at the audio system via the user interface CAN, gateway for the user interface CAN and the chassis CAN to the Electronic Stability Program (ESP) control unit.
Model 447.6/7:
- Operating interventions on the radio (Audio) are transmitted via the interior CAN, instrument cluster (IC) control unit and chassis CAN to the Electronic Stability Program (ESP) control unit.
The steering column tube module control unit sends information about control interventions at the cruise control lever, the combination switch, and the left and right multifunction steering wheel button groups via the chassis CAN to the Electronic Stability Program (ESP) control unit.
The control interventions at the left and right multifunction steering wheel button groups are read in by the steering wheel electronics and sent via the steering LIN to the steering column tube module (MRM) control unit.
Suppression of a warning message
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 = 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 the development of driving behavior. 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.
- No warning because of restrictions associated with the system limits:
The driving behavior 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 types of driver present particular challenges for attention assistance systems, e.g. drivers with extremely smooth or extremely active steering behavior.
- Influence of time on sensitivity of the attention assistance system:
The attention assistance system reacts in accordance with the human biorhythm 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 sensitivity of the attention assistance system:
The attention assistance system responds with increasing sensitivity as the driving time without a break 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 driving behavior 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 feeling of fatigue and the objective assessment variable determined by the attention assistance system may also differ.
- Change in steering ability through other factors:
In addition 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 assistance system, e.g. increasingly slippery road surface, worsening visibility, narrowing roadway, worsening roadway.
| Overview of system components for driver assistance systems | GF54.00-S-9998TRF |