Active Safety System Description and Operation: Notes

The active safety system is a comprehensive feature set designed to help a driver avoid collisions or reduce crash damage while driving, backing and parking. The active safety control module is the primary controller for the active safety system. The active safety control module communicates on multiple serial data busses to share information with various control modules throughout the vehicle. The active safety control module uses various sensors and control modules to monitor the vehicle surroundings and take deliberate action to avoid collisions or reduce crash damage. The active safety system tightly integrates the forward collision alert, adaptive cruise control, front and rear parking assist and active emergency braking systems into a single cohesive system.

The active safety control module communicates via serial data on the object detection bus with the vehicle direction camera, radar sensor module - long range, radar sensor module - short range left front and radar sensor module - short range right front to create a virtual fusion image of the area in front of the vehicle. The active safety control module observes an actual visual image of the area directly ahead of the vehicle, within 60 m (197 ft), with the vehicle direction camera. The radar sensor module - long range is used to measure the distance to objects that are up to 200 m (656 ft) in front the vehicle and the two radar sensor modules - short range are used to measure the distance to objects that are within 30 m (98 ft) of the front of the vehicle. Within 60 m (197 ft) of the vehicle, all of these inputs are combined to create a fusion image of the area in front of the vehicle. At up to 200 m (656 ft), the radar sensor module - long range will detect and begin tracking objects immediately in front of the vehicle. Within 60 m (197 ft), the vehicle direction camera will confirm objects that have been detected by the radar sensor module - long range. The two radar sensor modules - short range improve cut-in detection, which are objects that enter the vehicle path from the side and are not necessarily detected by the vehicle direction camera and radar sensor module - long range, who's focus are those object directly in front of the vehicle.

The fusion image created by the active safety control module is used to detect collision risks and take action based on the immediacy of the risk. The a collision risk exists, the active safety control module will alert the driver using the forward collision alert system. This will provide the driver with a visual and audible or haptic alert that a collision risk has been detected. If the driver does not take action to reduce the risk of collision, such as changing lanes or applying the brakes, the intelligent brake assist system will pre-fill the brake hydraulic system to reduce system response time and increase pressure when quickly applying the brakes. If a collision risk is imminent, the active safety control module will enter automatic collision preparation, which will automatically apply the brakes in an effort to mitigate the collision or reduce collision damage.

The active safety control module communicates with the steering wheel angle sensor and the multi-axis acceleration sensor via serial data on the chassis expansion bus. These sensors are used to determine the intended vehicle path. Using the steering data and vehicle acceleration data, the active safety control module will determine where the vehicle will be traveling and focus attention on objects in this path. An example would be a driver quickly changing lanes to avoid a collision. This would mitigate the collision risk in the previous lane and the active safety control module would quickly transition to tracking objects for any collision risk in the new lane based on intended vehicle path. The active safety control module also communicates with the electronic brake control module to instigate the braking functions of intelligent brake assist and automatic collision preparation.

At the rear of the vehicle, the active safety control module uses the radar sensor module - short range left rear, radar sensor module - short range right rear and the front and rear parking assist control module as part of the backing warning system and the rear automatic braking system. Typical rear parking assist utilizes the front and rear parking assist control module and the four ultrasonic rear parking assist sensors to detect object when reversing at speed of up to 8 km/h (5 mph). The backing warning systems utilizes both the four ultrasonic rear parking assist sensors, as well as the radar sensor module - short range left rear and radar sensor module - short range right to detect object at speeds above 8 km/h (5 mph). The rear automatic braking system is intended to help avoid or reduce the harm caused by backing crashes or prevent the vehicle from being from being reversed into an object if the vehicle is already stopped.

The active safety system analyzes data from the various control modules and sensors listed below:

• Active safety control module
• Vehicle direction camera
• Radar sensor module - long range
• Radar sensor module - short range left front
• Radar sensor module - short range right front
• Radar sensor module - short range left rear
• Radar sensor module - short range right rear
• Front and rear parking assist control module
• Electronic brake control module