BMW G12 Product Information page 147

G12￿Driver￿Assistance￿Systems
22.￿Lane￿&￿Traffic￿Jam￿Assistant
• Speed￿must￿be￿below￿210￿km/h.
• Above￿70￿km/h:￿both￿lane￿edges￿must￿be￿detected.
• Below￿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￿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￿is￿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￿70 km/h.
• The￿lane￿control￿assistant￿can￿be￿enabled￿within￿a￿speed￿range￿of￿70 to￿210 km/h.
22.1.3.￿Lane￿change
For￿a￿lane￿change￿to￿be￿as￿comfortable￿as￿possible,￿the￿steering￿and￿lane￿control￿assistant￿including
traffic￿jam￿assistant￿is￿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.
22.1.4.￿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.
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