GF54.30-P-0009CE Attention Assist, Function
GF54.30-P-0009CE Attention Assist, Function
MODEL 204.0 /2
- with CODE (442) Comfort multifunction steering wheel as of model year 2012 /YoM 11 model refinement package
MODEL 204.3
- with CODE (442) Comfort multifunction steering wheel
A1 Instrument cluster
A1h1 Warning buzzer
A1p13 Multifunction display
A2 Radio (with code (510) Audio 20 with CD changer or code (523) MB Audio 20 radio)
A40/3 COMAND control unit (with code (512) COMAND APS incl. DVD changer or code (527) COMAND APS with single DVD drive (with navigation) or code (528) COMAND incl. DVD changer)
B24/15 Yaw rate sensor for lateral and longitudinal acceleration (model 204.077/277/377 and with code (233) DISTRONIC PLUS, code (237) Active Blind Spot Assist, code (238) Active Lane Keeping Assist)
B38/2 Rain/light sensor
L6/1 Left front axle speed sensor
L6/2 Right front axle speed sensor
L6/3 Left rear axle speed sensor
L6/4 Right rear axle speed sensor
N10/1 Front SAM control unit with fuse and relay module
N30/4 Electronic Stability Program control unit
N49 Steering angle sensor
N73 Electronic ignition switch control unit
N80 Steering column module control unit
N135 Steering wheel electronics
S4 Combination switch
S40/4 Cruise control lever
S59 Steering column adjustment switch (with code (275) Memory package for electrically adjustable front seats)
S110 Left multifunction steering wheel button group
S110s6 Press OK n/
S111 Right multifunction steering wheel button group
CAN B Interior CAN
CAN E Chassis CAN
CAN H Vehicle dynamics CAN
LIN E1 Steering LIN
LIN 2 Wiper/inside rearview mirror LIN
Function requirements, general
^ Circuit 15 ON
The electronic ignition lock control unit sends the status of circuit 15 via the chassis CAN to the Electronic Stability Program control unit.
Attention Assist, general
The attention assistance system function is integrated in the Electronic Stability Program control unit and detects fatigue or increasing inattentiveness (e.g. for lengthy, monotonous journeys on freeways and highway) in a vehicle speed range from v = 80 to 180 km/h.
If the attention assistance system function detects any indication of driver fatigue or increasing inattentiveness, the driver is prompted to take a break by means of visual and acoustic warnings. To this end, the driver handling characteristics are 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.
Function sequence for Attention Assist
The Attention Assist function can be switched on or off in the "Assist." menu in the "Attention Asst." menu level on the instrument cluster.
The status of the attention assistance system is sent by the instrument cluster over the chassis CAN to the Electronic Stability Program control unit.
Attention assistance system function ON
1 Coffee cup symbol
If the attention assistance system function is active, a coffee cup symbol is shown in the multifunction display of the instrument cluster.
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 influences (e.g. surface undulations or crosswind)
The driver handling characteristics are also analyzed when the attention assistance system is switched off. If the system is switched on during a journey the complete journey after the start is then 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 corresponding to the driving time and the time of day.
If the warning threshold has been exceeded, the Electronic Stability
Program control unit sends a request to issue a warning message and a warning tone via the chassis CAN to the instrument cluster.
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 directly reads in the status of the OK button and sends 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 to the Electronic Stability Program control unit.
A repeated warning message can only be issued following expiry of t > 15 minutes.
The algorithm for the Attention Assist function mainly processes the following information:
- 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 information via the chassis CAN to the Electronic Stability Program control unit.
Based on the evaluation of ambient brightness by the rain/light sensor, the received time is checked for plausibility.
To this end the current ambient light intensity is recorded by the rain/light sensor.
The front SAM control unit reads in the rain/light sensor data over the wiper/inside rearview mirror LIN and sends the data over the chassis CAN 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.
Vehicle longitudinal / lateral acceleration and yaw rate:
The yaw rate sensor for lateral and longitudinal acceleration (with code (233) DISTRONIC PLUS, code (237) Active Blind Spot Assist or code (238) Active Lane Keeping Assist, model 204.077/277/377) provides information on the yaw behavior of the vehicle and sends this information via the vehicle dynamics CAN to the Electronic Stability Program control unit.
On vehicles without code (233) DISTRONIC PLUS, code (237)
Active Blind Spot Assist, code (238) Active Lane Keeping Assist and except model 204.077/277/377, the yaw rate sensor for lateral and longitudinal acceleration is integrated in the Electronic Stability Program control unit.
Steering movements:
The steering movements are detected by the steering wheel angle sensor and sent by the steering column tube module control unit via the chassis CAN 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 following components and read in directly by the Electronic Stability Program control unit:
- Left front axle speed sensor
- Right front axle speed sensor
- Left rear axle speed sensor
- Right rear axle speed sensor
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
- Left multifunction steering wheel button group or right multifunction steering wheel button group
Control interventions are recorded as follows:
The control interventions at the control buttons on the radio or on the COMAND controller unit are sent by the radio or the COMAND controller unit via the interior CAN to the front SAM control unit which forwards the information via the chassis CAN to the Electronic Stability Program control unit.
The control interventions at the steering column adjustment, combination switch and cruise control lever are directly read in by the steering column tube module control unit.
The steering column tube module control unit also reads in the control interventions from the multifunction steering wheel button groups through the steering wheel electronics over the steering LIN. The steering column tube module control unit sends this information over the chassis CAN to the Electronic Stability Program control unit.
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:
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, no warning will be issued.
2. No warning because of restrictions associated with the system limits:
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 driver types present specific challenges to the system, e.g. driver with extremely smooth or extremely active steering ability.
4. Influence of time on sensitivity of function:
The attention assistance function responds in accordance with the human biorhythm depending on the time (e.g. including the afternoon slump). These results are determined representatively, but they may also differ on an individual basis.
5. Influence of driving time on system sensitivity:
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:
Attention Assist 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 system are different.
7. Change in steering ability through other factors:
Next to fatigue or increasing inattentiveness other factors can also significant 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.
