BAS PLUS, function - GF30.30-P-3310GN
MODEL 166 as of model year 2016 with CODE 268 (Brake Assist System Plus) with CODE 269 (Brake Assist PLUS with Cross-Traffic Assist (BAS+Q)
MODEL 292 with CODE 268 (Brake Assist System Plus) with CODE 269 (Brake Assist PLUS with Cross-Traffic Assist (BAS+Q)
Block diagram, except model 166.063
Block diagram, model 166.063
Function requirements, general
- No undervoltage or overvoltage
- "BasExtd_Avl" (with CODE (268) Brake Assist PLUS) programmed in electronic ignition lock control unit
- "BasPlusQ_Avl" (with CODE 269 (BRAKE ASSIST SYSTEM PLUS CROSSING TRAFFIC)) programmed in electronic ignition lock control unit
- Engine running or drivetrain operational
- Radar sensor system soiling and function test for the radar sensor system completed successfully
Object recording (e.g. vehicle ahead) via the radar sensor system is based on the radar measuring procedure. The front long range radar sensor and the front bumper radar sensors run a contamination and function test after each engine start to ensure that they are functioning correctly. The function test requires an object in the respective detection range which is used as a reference for the function test. If a malfunction is detected or if there are no objects in the detection range (for the function test), BAS PLUS cannot be activated. The front bumper radar sensors send corresponding signals via radar CAN 1, radar sensors control unit (with CODE 23P (Driving assistance package Plus)) and chassis FlexRay to the front long range radar sensor. The front long range radar sensor evaluates these with its own signals and, when all the radar sensors are functioning correctly, sends the "Radar sensor system operational" status via chassis FlexRay to the radar sensors control unit (with CODE 23P (Driving assistance package Plus)).
- Electronic Stability Program (ESP®) not switched to passive mode (except AMG)
- ESP® not switched to "SPORT HANDLING MODE" (with AMG)
- No active ESP® intervention recognized (vehicle not in sliding movement)
- Gear range "D" engaged (vehicle not in backward movement)
- Vehicle speed v = 7 to 250 km/h
- Standstill control, enable issued (driver door/driver belt buckle and front passenger door closed)
The CDI control unit or ME-SFI [ME] control unit sends the "engine running" or "drivetrain operational" signal via the chassis CAN 1, chassis gateway control unit (with CODE 23P (Driving assistance package Plus)), and chassis FlexRay to the radar sensors control unit (with CODE 23P (Driving assistance package Plus)).
The ME-SFI [ME] control unit sends the "engine running" or "drivetrain operational" signal via the engine CAN, powertrain control unit, chassis CAN 1, chassis gateway control unit (with CODE 23P (Driving assistance package Plus)), and chassis FlexRay to the radar sensors control unit (with CODE 23P (Driving assistance package Plus)).
The Electronic Stability Program control unit sends the status of the ESP® via chassis CAN 1, chassis gateway control unit (with CODE 23P (Driving assistance package plus)) and chassis FlexRay to the radar sensors control unit (with CODE 23P (Driving assistance package plus)).
The acceleration/turn rate is detected by the yaw rate sensor for lateral and longitudinal acceleration. The yaw rate sensor for lateral and longitudinal acceleration transmits appropriate values via the dynamics CAN to the Electronic Stability Program control unit. The Electronic Stability Program control unit sends this information via the chassis CAN 1, chassis gateway control unit (with CODE 23P (Driving assistance package plus)), and chassis FlexRay to the radar sensors control unit (with CODE 23P (Driving assistance package plus)).
The fully integrated transmission control unit sends information on the engaged gear range via the drive train CAN, CDI control unit or the ME-SFI [ME] control unit, chassis CAN 1, chassis gateway control unit (with CODE 23P (Driving assistance package Plus)) and chassis FlexRay to the radar sensors control unit (with CODE 23P (Driving assistance package Plus)).
The vehicle speed is calculated from the wheel speeds, the direction of travel is defined by the wheel rotation direction. The Electronic Stability Program control unit sends this information via the chassis CAN 1, chassis gateway control unit (with CODE 23P (Driving assistance package Plus)), and chassis FlexRay to the radar sensors control unit (with CODE 23P (Driving assistance package Plus)).
BAS PLUS, general
BAS PLUS can not only support the driver in avoiding rear-end collisions in linear traffic or in minimizing its consequences, but can also provide support in case of a risk of collisions with the cross traffic at intersections (Intersection Assist) and with pedestrians. If BAS PLUS recognizes this type of hazard situation, it prompts the driver to perform emergency braking using visual and acoustic warnings. If the driver operates the brake too tentatively, BAS PLUS automatically increases the brake pressure for effective braking, up to emergency braking if necessary. The brake application which is metered according to the situation is also makes the greatest possible braking distance available for the traffic to the rear.
In a vehicle speed range of v = 7 to 250 km/h the BAS PLUS is activated in a possibly dangerous situation. BAS PLUS is only activated for stationary obstacles, crossing vehicles and pedestrians when the vehicle speed is a maximum of v = 72 km/h. It is controlled by the radar sensors control unit (with CODE 23P (Driving assistance package Plus)), which actively intervenes into the brake system.
Function sequence for BAS PLUS
BAS PLUS assumes that the following conditions are given when implementing the function:
- Object detection in longitudinal direction
- Detection of objects crossing the lane (with CODE 269 (BRAKE ASSIST SYSTEM PLUS CROSSING TRAFFIC))
- Detection of stationary and slow-moving pedestrians (with CODE 271 (Autonomous brake intervention/pedestrian protection))
Object detection in longitudinal direction:
Object detection long range takes place by the long range radar sensor at the front.
The front long range radar sensor monitors the area in front of the vehicle up to a distance of s = 200 m within a corridor of ∠ = 18°.
Objects up to a distance of s = 0 to 60 m are detected in a corridor of ∠ = 60°.
The front long range radar sensor operates according to the pulse modulated Doppler radar concept, which enables the distances and speeds of individual objects (e.g. vehicles) to be measured independently of each other.
The front long-range radar sensor sends corresponding signals via chassis FlexRay to the radar sensors control unit (with CODE 23P (Driving assistance package Plus)).
Up to a distance of s = 30 m, objects are detected by the front bumper radar sensors (short range radar sensor system). Object detection by the short range radar sensor system is merely used for the plausibility check.
The front bumper radar sensors send appropriate signals via the radar CAN 1 to the radar sensors control unit (with CODE 23P (Driving assistance package Plus)).
Detection of objects crossing the lane (with CODE 269 (BRAKE ASSIST SYSTEM PLUS CROSSING TRAFFIC)):
Crossing objects are detected by the front long range radar sensor and the stereo multifunction camera (with CODE 23P (Driving assistance package Plus)) in the vehicle speed range of v = 7 to 72 km/h depending on their condition (height, width) and their closing speed. The stereo multifunction camera (with CODE 23P (Driving assistance package Plus)) is located in the upper area of the windshield and supplies the following data:
- Relative position of object crossing driving lane corridor
- Side closing speed
The stereo multifunction camera (with CODE 23P (Driving assistance package plus)) consists of two high-resolution mono cameras and an integrated control unit for evaluation and plausibility check of the picture data provided. The laterally offset location of the two mono cameras creates a difference in perspective (parallax displacement) between the left and right optical path. The distance to the detected object and other variables such as the height, size and circumference or the speed of motion can be evaluated on the basis of the differences between the image data.
The image data from the two mono cameras is prepared by the integrated control unit and sent via chassis FlexRay to the radar sensors control unit (with CODE 23P (Driving assistance package Plus)). The radar sensors control unit (with CODE 23P (Driving assistance package Plus)) compares the image data with the signals from the radar sensor system.
The following traffic situations delineate the limits of the BAS PLUS:
- Objects such as walls or trees prevent acquisition of any objects approaching from the side
- Contours of larger vehicles overlay the smaller vehicles
- Vehicles approaching from the side at high speed
Detection of stationary and slow-moving pedestrians:
Pedestrians located in an area at the side of the lane can be detected in a vehicle speed range of v = 0 to 72 km/h.
Persons are detected by the stereo multifunction camera (with CODE 23P (Driving assistance package Plus)) and the front long range radar sensor.
The radar sensor system detects people or objects, and it can conduct positioning within a defined range - dependent on the distance from the person or object involved and the vehicle speed. It is not however capable of performing exact position finding in a transverse direction. This is why redundant detection by the stereo multifunction camera (with CODE 23P (Driving assistance package plus)) is required.
If BAS PLUS recognizes a risk of a collision with a vehicle or a person, the driver is supported during braking.
At speeds of < 30 km/h:
- If the brake pedal is actuated, BAS PLUS is activated. The brake support by BAS PLUS occurs at the last possible moment.
At speeds of > 30 km/h:
- If the brake pedal is actuated hard (emergency braking), BAS PLUS automatically increases the brake pressure to a value adapted to the traffic situation.
The emergency braking is defined over the speed and the strength with which the brake pedal is actuated.
The Electronic Stability Program control unit the braking request of the driver about the increasing brake pressure in the master brake cylinder. The brake pressure is registered by the front axle brake pressure sensor. The Electronic Stability Program control unit directly reads in the signal of the front axle brake pressure sensor and sends the corresponding value via chassis CAN 1, chassis gateway control unit (with CODE 23P (Driving assistance package Plus)) and chassis FlexRay to the radar sensors control unit (with CODE 23P (Driving assistance package Plus)).
The radar sensors control unit (with CODE 23P (Driving assistance package Plus)) uses the data from the front long range radar sensor in combination with that from the front bumper radar sensors and the stereo multifunction camera (with CODE 23P (Driving assistance package Plus)), calculates the required braking torque and sends the request "Increase braking torque" via chassis FlexRay, chassis gateway control unit (with CODE 23P (Driving assistance package Plus)) and chassis CAN 1 to the Electronic Stability Program control unit, which then actuates the traction system hydraulic unit directly.
In model 166.063, the kinetic energy is converted into electrical energy via a generator (regenerative braking) within defined limits. If the required braking torque exceeds the deceleration through regenerative braking (for example, in the event of emergency braking), the Electronic Stability Program control unit also actuates the traction system hydraulic unit and therefore the service brake.
If there is no actuation or the intensity of actuation of the brake pedal by the driver decreases, the brake boost is reduced to the driver braking level and the BAS PLUS function is deactivated. If the driver presses the accelerator pedal, BAS PLUS is also deactivated.
If the driver requests a higher braking torque than that required by BAS PLUS in a specific situation, then the driver request has priority.
| Electrical function schematic for BAS PLUS | PE30.30-P-2063-97NBA |
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