BAS PLUS, function - GF30.30-P-3310RF
Model 205, 253 with code 268 (Brake Assist System Plus)
Model 205, 253 with code 269 (Brake Assist PLUS with Cross-Traffic Assist (BAS+Q)
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 PLUS crossing traffic (BAS+Q)) programmed in electronic ignition lock control unit
- System fault-free (no faults detected by function-specific error management)
- 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 area, and is used as a reference object. If a malfunction is established or if there are no objects in the detection area, the BAS PLUS cannot be activated. The radar sensors control unit receives the signals of the front bumper radar sensors via the radar-CAN 1 and sends them over the chassis FlexRay to the front long range radar sensor. The front long range radar sensor evaluates them in combination 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.
- Soiling and function test for the stereo MFK
- Electronic Stability Program (ESP®) not switched to passive mode
- No active ESP® intervention recognized (vehicle not in sliding movement)
- Gear range "D" engaged (vehicle not in backward movement)
- Vehicle speed of v = 7 to 250 km/h
- Standstill coordinator, enable issued (driver door/driver belt buckle and front passenger door closed)
The electronic ignition lock control unit transmits the signal "Brake Assist PLUS" and "Brake Assist PLUS crossing traffic" via the suspension FlexRay to the radar sensors control unit and the stereo MFK.
The CDI control unit or the ME-SFI [ME] control unit sends the "Engine running" or "Drivetrain operational" signal to the radar sensors control unit via the drive train CAN, powertrain control unit and chassis FlexRay.
The Electronic Stability Program control unit sends the status of the Electronic Stability Program® via the suspension FlexRay to the radar sensors control unit.
The acceleration/yaw rate is detected by the acceleration sensor integrated into the Supplemental Restraint System control unit. The supplemental restraint system control unit sends the corresponding values via the vehicle dynamics CAN to the Electronic Stability Program control unit. The Electronic Stability Program control unit transmits these via the suspension FlexRay to the radar sensors control unit.
The fully integrated transmission control unit sends information about the selected gear range via drive train CAN, powertrain control unit and suspension FlexRay to the radar sensors control unit.
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 transmits the wheel speed signals via the suspension FlexRay to the radar sensors control unit.
BAS PLUS, general
BAS PLUS can not only support the driver in avoiding rear-end collisions in linear traffic or in minimizing their consequences, but can use the new Intersection Assist function as support in case of a risk of collisions with the cross traffic at intersections (with code 269 (Brake Assist PLUS Cross Traffic (BAS+Q)). The pedestrian recognition in the BAS PLUS system can avoid a collision with pedestrians or reduce the severity of the impact. If the driver actuates the brakes in a dangerous situation to cautiously, the BAS PLUS automatically increases the brake pressure for an effective emergency braking, in an emergency up to emergency braking. 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 the vehicle speed range of v = 7 to 250 km/h, BAS PLUS is activated in a potentially hazardous situation. BAS PLUS is only activated for stationary obstacles, pedestrians and crossing vehicles when the vehicle speed is a maximum of v = 72 km/h. The controlling takes place by the radar sensors control unit, which actively intervenes in 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 (BAS+Q)))
- Detection of stationary and slow-moving pedestrians
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 information via the chassis FlexRay to the radar sensors control unit.
From a distance of s = 30 m object detection is also performed by the front bumper radar sensors (short range radar sensor system). The object detection by the short range radar sensor system simply serves to allow plausibility checking.
The front bumper radar sensors send information via the radar CAN 1 to the radar sensors control unit.
Detection of objects crossing the lane (with code 269 (Brake Assist system PLUS crossing traffic (BAS+Q))):
Crossing objects and pedestrians are detected in a vehicle speed range of v = 7 to 72 km/h dependent on their nature (height, width) and their closing speed by front long range radar sensors and the stereo MFK.
The stereo multifunction camera is located in the upper area of the windshield and supplies the following data:
- Relative position of an object and pedestrians crossing the driving lane corridor
- Side closing speed
The stereo multifunction camera consists of two high-resolution mono cameras and an integrated control unit for evaluation and a plausibility check of the supplied picture data. The 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. The radar sensors control unit compares the image data with the signals from the radar sensor system.
The following traffic situations show the limits of the BRAKE ASSIST SYSTEM PLUS CROSS TRAFFIC (BAS+Q):
- 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.
Pedestrians are detected by the stereo multifunction camera 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 pedestrians or to the object involved and the vehicle speed. It is not however capable of performing exact positioning in the transverse direction. This is why redundant detection by the stereo multifunction camera is required.
If BAS PLUS detects a threat of collision with a vehicle or a pedestrian, the driver is supported during braking.
At a speed 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 a speed of < 30 km/h:
- If the brake pedal is pressed down forcefully (emergency braking), the BAS PLUS increases the brake pressure automatically up to a value adapted to the traffic situation.
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 from the front axle brake pressure sensor, calculates the braking torque requested by the driver and sends this information via the chassis FlexRay to the radar sensors control unit. The radar sensors control unit uses the data from the long range radar sensor in combination with that from the front bumper radar sensor and the stereo MFK, calculates the required braking torque and transmits the request via the chassis FlexRay to the Electronic Stability Program control unit which reacts by directly activating the traction system hydraulic unit.
If there is no actuation occurs or the intensity of actuation of the brake pedal by the driver reduces, the brake servo assistance 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.
Model 205.012/047/147/212/247
with code 268 (Brake Assist System Plus)
Model 205.012/047/147/212/247
with code 269 (Brake Assist PLUS with Cross-Traffic Assist (BAS+Q)
The kinetic energy is converted within defined limits into electrical energy (regenerative braking). If the required braking torque exceeds the deceleration through regenerative braking (for example in the event of emergency braking), then the Electronic Stability Program control unit also actuates the traction system hydraulic unit and therefore the service brake.
| Electrical function schematic for BAS PLUS | PE30.30-P-2063-97FBA |
| Overview of system components for driver assistance systems | GF54.00-P-9998RF |