Introduction to the eight functional systems of ADAS

This article mainly introduces the eight functional systems of ADAS.

1. Lane Departure Warning System

LDWS Lane departure warning system LDWS (Lane departure warning system) refers to the situation where the vehicle suddenly deviates from the lane without turning on the turn signal. When the deviation is abnormal, once the dashcam determines that the driving route is different, it will remind the driver with the display screen of the dashcam and issue a sound warning to warn the driver. This will enable the driver to take immediate action and return to the original lane. The lane departure warning system is mainly composed of HUD head-up display, camera, controller and sensor. When the lane departure warning system is turned on, the camera (usually placed on the side of the car body or the rearview mirror position) will always collect the marking line of the driving lane and obtain the position parameters of the car in the current lane through image processing. When the car is detected to deviate from the lane, the sensor will collect vehicle data and the driver's operating status in time, and then the controller will issue an alarm signal. The whole process is completed in about 0.5 seconds, providing more reaction time for the driver. If the driver turns on the turn signal and changes lanes normally, the lane departure warning system will not make any prompts.

2. Lane Keeping System

Lane Keeping Assist System LKS (Lane Keeping System) is a kind of intelligent driving assistance system. It can control the control coordination device of the brake on the basis of the Lane Departure Warning System (LDWS). It supports the vehicle to keep in the lane by using a camera to identify the marking line of the driving lane. It can detect the position of the vehicle in the lane and automatically adjust the steering to keep the vehicle in the lane. If the vehicle approaches the identified marking line and may leave the driving lane, the driver will be alerted by the vibration of the steering wheel or sound, and the steering wheel will be slightly turned to correct the driving direction so that the vehicle is in the correct lane. If the steering wheel detects that no one actively intervenes for a long time, an alarm will be issued to remind the driver. If the lane keeping assist system recognizes the marking lines on both sides of the lane, the system is in standby mode. This is displayed by the green indicator light in the instrument cluster. When the system is in standby mode, if the turn signal is turned on before crossing the marking line, the warning signal will be blocked and the driver will be deemed to have consciously changed lanes. This system is mainly used on structured roads, such as highways and roads with good road conditions (clear lane lines). It starts running when the vehicle speed reaches 65km/h or above.

3. Adaptive Cruise Control System ACC

Adaptive Cruise Control (ACC) is a comfortable auxiliary driving function. If the road ahead is clear, the adaptive cruise control (ACC) will maintain the set maximum cruising speed and drive forward. If a vehicle is detected ahead, the adaptive cruise control (ACC) will reduce the speed as needed and maintain a distance from the vehicle ahead based on the selected time until the appropriate cruising speed is reached. Adaptive cruise control can also be called active cruise control, which is similar to traditional cruise control. The system includes a radar sensor, a digital signal processor and a control module. In the adaptive cruise control system, the system uses low-power radar or infrared beams to obtain the exact position of the vehicle ahead. If the vehicle ahead slows down or detects a new target, the system will send an execution signal to the engine or brake system to reduce the speed, so that the vehicle and the vehicle ahead can maintain a safe driving distance. When the obstacle on the road ahead is cleared, it will accelerate back to the set speed, and the radar system will automatically monitor the next target. The active cruise control system controls the speed instead of the driver, avoiding frequent cancellation and setting of cruise control. When the distance to the vehicle ahead is too small, the ACC control unit can coordinate with the anti-lock braking system and the engine control system to brake the wheels appropriately and reduce the output power of the engine, so that the vehicle and the vehicle ahead can always maintain a safe distance. The adaptive cruise control system is suitable for a variety of road conditions and provides drivers with a more relaxed driving experience.

4. Front Collision Prevention System FCW

The forward collision prevention system FCW (Forward Collision Warning) uses a radar system to constantly monitor the vehicle ahead, determine the distance, direction and relative speed between the vehicle ahead and the vehicle ahead, and warn the driver when there is a potential collision risk. The FCW system itself will not take any braking measures to avoid collision or control the vehicle. The vehicle ahead is identified and tracked by analyzing the road ahead information obtained by the sensor. If a vehicle is identified, the distance to the vehicle ahead is measured. At the same time, the vehicle speed is estimated and the possibility of rear-end collision is determined based on the safe vehicle distance warning model. Once there is a risk of rear-end collision, the driver will be given an active warning in a timely manner according to the warning rules.

5. Automatic Parking System APA

The automatic parking system APA (Automatic Parking Assist) uses on-board sensors (usually ultrasonic radar or camera) to identify effective parking spaces and control the vehicle to park through a control unit. Compared with traditional reversing assistance functions, such as reversing images and reversing radars, the automatic parking function is more intelligent and effectively reduces the driver's reversing difficulties. The fully automatic parking assistance system APA automatically parks the vehicle by controlling the acceleration and deceleration and steering angle of the vehicle. The system perceives the parking environment through AVM (surround view) and USS (ultrasonic radar), estimates the vehicle posture (position and driving direction) using IMU and wheel sensors, and automatically or manually sets the target parking space according to the driver's choice. The system then calculates the automatic parking trajectory, and through precise vehicle positioning and vehicle control systems, the vehicle is fully automatically parked along the defined parking trajectory until it reaches the final target parking space.

6. Blind Spot Monitoring System (BSD)

Since there is a visual blind spot in the rearview mirror of a car, the vehicle in the blind spot cannot be seen before changing lanes. If there is an overtaking vehicle in the blind spot, a collision accident will occur when changing lanes. In heavy rain, foggy weather, and dim light at night, it is even more difficult to see the vehicle behind, and changing lanes at this time faces greater danger. The blind spot monitoring system is created to solve the blind spot of the rearview mirror. The blind spot monitoring system BSD (Blind Spot Detection) is a high-tech safety configuration on the car. Its main function is to eliminate the blind spot of the rearview mirror. It relies on two radars at the rear of the vehicle to monitor the side and side status of the vehicle at all times. If the vehicle is located in this area, the driver will receive relevant warning prompts through the blind spot warning indicator on the rearview mirror and the instrument cluster to avoid accidents caused by the blind spot of the rearview mirror during lane changes.

7. Driver Fatigue Warning System DFM

The Driver Fatigue Monitor System (DFM) mainly uses images obtained by the camera to detect the driver's driving behavior and physiological state through visual tracking, target detection, motion recognition and other technologies. When the driver is in dangerous situations such as fatigue, distraction, making phone calls, smoking, etc., the system will alarm within the set time to avoid accidents. The DFM system can effectively regulate the driver's driving behavior and greatly reduce the probability of traffic accidents. By analyzing the driver's fatigue characteristics (such as yawning, closing eyes, etc.), fatigue driving warnings are issued in time for fatigue behavior. The high-precision algorithm can even be unaffected by external conditions such as time period, lighting conditions, whether or not to wear sunglasses, and always effectively manage the driver's fatigue state. When the driver is in a state of physiological fatigue, an early warning warning is immediately issued to wake the driver in time to avoid serious accidents.

8. Adaptive Lighting Control ALC

Adaptive Light Control (ALC) is an intelligent lighting adjustment system. By sensing the driver's operation, vehicle driving status, road surface changes, weather conditions and other information, AFS automatically controls the headlights to adjust the lighting angle up and down and left and right in real time to provide the driver with the best road lighting effect.

The adaptive headlight system consists of four parts: sensors, ECU, headlight control system and headlights. The vehicle speed sensor and steering wheel angle sensor continuously transmit the detected signals to the ECU. The ECU processes the signals detected by the sensor, judges the processed data, and outputs the headlight angle command to make the headlight turn to the corresponding angle. When the car is turning, the key is to see the obstacles in the direction of the turn in advance. According to the experience of real driving, the headlights generally only need to turn 0 to 15 degrees. Only the headlight on the side of the turn direction needs to realize intelligent steering, and the headlight on the other side still maintains the original direction. Although the control is simplified, the expected effect can still be achieved. It can significantly improve the lighting effect under various road conditions through the control system and improve driving safety.