BMW 5 Series: Functional prerequisites

The following prerequisites must be met in order for the Active Lane Keeping Assistant and Traffic Jam Assistant to be used:

• Speed must be below 130 mph (210 km/h).
• Above 43 mph (70 km/h): both lane edges must be detected.
• Below 43 mph (70 km/h): both lane edges or a vehicle driving ahead must be detected.
• The lane width must be sufficient.
• The vehicle should be positioned as centrally as possible in the lane.
• There must be a sufficient curve radius.
• At least one hand must be on the steering wheel rim.
• The turn indicator must not be activated.
• The camera calibration process must be completed immediately after vehicle delivery.

The active lateral control function with data evaluation of the KAFAS stereo camera is implemented with the assistance of the lane markings identified on the left and right.

In order for the system to be activated, two lane boundary lines must be detected. Below a speed of approximately 43 mph (70 km/h) a vehicle driving ahead in the same lane is sufficient to activate the system.

The system is put in Standby mode if the marginal conditions are not satisfied (e.g. hands not on steering wheel, lane too narrow or dazzling of KAFAS stereo camera). Once all marginal conditions have been met, the system is re-enabled automatically.

To activate the system, the speed of the vehicle is another input quantity that is evaluated. The system uses these values to decide which function will be enabled. As mentioned above, the threshold values are set as follows:

• The Traffic Jam Assistant can be enabled within a speed range of 0 to approximately 43 mph (70 km/h).
• The Active Lane Keeping Assistant can be enabled within a speed range from approximately 43 to approximately 130 mph (70 to approximately 210 km/h).

Lane change

For a lane change to be as comfortable as possible, the Active Lane Keeping Assistant and Traffic Jam Assistant are put silently into Standby mode when the turn indicator is activated and reactivates itself automatically once the turn indicator is back in its initial position and a lane change has occurred.

Function logic

The main function logic of the lateral guidance is implemented in the Optional Equipment System (SAS) control unit.

The majority of the data for the function is provided by the KAFAS stereo camera, where algorithms for the lane and object detection run.

Vehicle dynamics data, such as the driving speed, wheel speeds, yaw rate, steering angle, lateral acceleration, longitudinal acceleration, etc., is provided by the rest of the vehicle network via a FlexRay or CAN connection.

A target trajectory (also known as a path curve) is calculated in the Optional Equipment System (SAS) control unit. This is used to determine whether a steering correction is required.

READ NEXT: