BMW 5 Series: Active Cruise Control with Stop&Go function

The Active Cruise Control with Stop&Go function (ACC Stop&Go) is offered as a function of the Active Driving Assistant Plus, optional equipment (OE 5AT), for the G30.

ACC Stop&Go adjusts a driver-specified set speed and, if required by the traffic situation, also automatically adjusts the preselected following distance to the vehicle driving ahead (detected vehicles include passenger cars, trucks and motorbikes). The application range of ACC Stop&Go ranges from higher speeds down to a standstill. The distance and the speed are automatically adjusted in this range.

G30 Active Cruise Control (ACC) Stop&Go

Depending on the stationary time, driving off from a standstill is performed automatically or in response to a prompt by the driver. ACC Stop&Go not only detects vehicles that are slowly coming to a stop, but also stationary vehicles.

Due to improved monitoring in front of the vehicle, the system is capable of reacting more quickly to vehicles swinging in and out and turning off.

The extended application range has been achieved by the incorporation of the KAFAS stereo camera.

Image data is evaluated by the ACC Stop&Go system. The KAFAS control unit clearly detects vehicles when their rear ends are recorded by the camera. In addition, the KAFAS control unit ensures that the driving lane information, vehicle positions and movements are determined.

Object detection provided by a combination of radar sensor and KAFAS stereo camera.

In addition to image data, radar data is also gathered and evaluated by the radar sensors. This fusion of image and radar data makes possible the clear identification of lane markings and the distinction between stationary vehicles and other fixed objects.

G30 Radar sensor/KAFAS stereo camera fusion: Radar sensor object detection

A 77 GHz radar sensor emits bundled electromagnetic waves. The echoes reflected by objects are received and evaluated by the radar sensor. This enables information about objects located in front of the radar sensor to be obtained. This information includes size, distance and the deduced speed. The system's radar sensor can identify vehicles ahead up to a distance of 650 ft (200 m), to a large extent irrespective of weather conditions.

The sensor is located behind the air inlet grille on the front bumper.

G30 Installation location of front radar sensor for ACC Stop&Go

1. Removable grille
2. Sensor for ACC Stop&Go

G30 Front radar sensor for ACC Stop&Go

1. Adjustment feature

Thanks to the radar sensor's improved detection capability and alignment with the image data from the KAFAS stereo camera, vehicles in neighboring lanes are also detected. If these vehicles are driving in their own lane, then ACC Stop&Go adapts the speed to the vehicle pulling in or vehicle ahead. As a result, a time lag selected by the driver is constantly maintained.

ACC Stop&Go adjusts the speed if there is no vehicle driving directly ahead and automatically switches to distance control if the sensor system detects a slower vehicle in its lane. The system's Stop&Go function brings the vehicle to a complete standstill if necessary.

Detecting the vehicle in front of the vehicle in front

Additionally detecting the vehicle in front of the vehicle in front is likewise new on the G30.

This is analyzed using the sensors already fitted. Object detection is based on a fusion of the front radar sensor and the KAFAS stereo camera. Both sensors are, in principle, capable of detecting a vehicle two positions ahead.

In most cases, the vehicle in front of the vehicle in front is, however, concealed by the vehicle in front, which is why the camera can generally not detect it. The front radar, however, consistently provides good detection quality here by "looking under" the vehicle in front.

The advantages of this are as follows:

• Improved "driver-like" speed governing behavior
• Smoother following driving ("ACC cruising")
• Enhanced dynamics for traffic light-controlled journeys
• Driver-like behavior when approaching distant objects

Evaluation of ultrasound data

Since both the front radar sensor and the KAFAS stereo camera are only of limited use for close-range monitoring, the ultrasonic data for the ACC Stop&Go system is evaluated for the first time on the G30.

The data is provided by the front ultrasonic sensors already described. These are needed to monitor the close range in front of the vehicle for freedom from obstacles.

Coupling to the navigation system

Improved cornering behavior is made possible by coupling ACC Stop&Go to the navigation system.

This contributes to a further improvement of driver-like behavior. This also takes into consideration the intention to turn off the road and intersections, among other aspects.

Restart time

The restart time after automatic braking to a stop by ACC Stop&Go previously of approximately 3 seconds has been raised to approximately 30 seconds on the G30.

The prerequisite for extended restarting is that the vehicle is located on a highway or a divided highway outside the town.

If the vehicle in front starts driving again after being stopped (for more than approximately 3 seconds or longer than approximately 30 seconds on highways and divided highways), a note is shown to the driver. To drive off again the driver must confirm this note by pressing the RES/CNCL button or the accelerator pedal.

Additional convenience is provided by the extended restart time without driver intervention.

ACC Stop&Go does not only support the driver in flowing traffic, but also in traffic jam situations, both on multiple-lane highways and ordinary roads and on urban arterial and ring roads.

The adjustment range for the set speed is limited to a maximum of 130 mph (210 km/h).

If ECO PRO or SPORT mode is activated, the Active Cruise Control with Stop&Go function is also set to a fuel-efficient or sporty driving style. Due to the fuel-efficient driving style in ECO PRO driving mode, in some situations the vehicle's speed may exceed or drop below the set speed, for example on downhill gradients or inclines.

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