Leverage sensor active safety system enhances preventive

In the future, the perfect vehicle safety system must fully integrate gyroscopes, accelerometers, steering wheel and brake pedal position detectors, and tire speed detection systems to accurately monitor and warn the car body parts.

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Automotive safety systems have evolved from passive to active forms. Passive safety systems seek to reduce personal injury in the event of an accident, but active safety systems emphasize the avoidance of accidents. This kind of prior prevention capability relies on various sensing devices installed inside and outside the car, such as radar, infrared, CMOS/CCD image sensors, and tire pressure monitoring systems (TPMS). Based on different security claims, these monitored data are calculated by a specific controller, analyzing the meaning of their representatives, and responding appropriately as quickly as possible. Advanced security systems that are currently in use or in development have presented an application boom in the market.

Pre-collision system acts as "inside and outside" protection

The occurrence of traffic accidents is mainly collision, and the reason for the collision is often related to the driver's lack of concentration (such as dozing or making a phone call), or poor line of sight, and the accident usually occurs only in an instant. Today's automakers are committed to the development of pre-crash safety systems, which can be divided into two types: protection for internal drivers (or passengers) and protection for pedestrians.

For the driver, when the pre-crash safety system detects the possibility of impact through the radar system, it will warn the driver that if the collision is still unavoidable, the automatic braking system will be started before 0.6 seconds. According to the driver's braking force, the brake hydraulic pressure is added to make the vehicle decelerate more accurate, so that the speed can be minimized. At the same time, the pre-crash system will also drive the motor in the seat belt system. The seat belt is rolled back and the occupant is fixed in the best position designed, such as adjusting the position of the headrest to prevent neck injury, or moving the seat to a position where the airbag can perform its maximum function, in order to reduce the impact. To the lowest. In addition, the system can also make control actions such as closing the window and the sunroof.

In the protection of pedestrians, when components such as radar, infrared or image sensors sense that the vehicle body is about to collide with pedestrians, the pre-crash system will urgently inform the driver and, when the collision is unavoidable, start the automatic braking system as described above. Explosion of the airbag at the bumper and front windshield to reduce damage to the head, chest and feet of the pedestrian.

Adaptive cruise system involved in vehicle handling

From passive safety to pre-crash systems, it is a last resort crash, but the best case is to prevent collisions beforehand. By deploying sensors around the car, more and more sensors, and more advanced digital control technology, today's owners can get assisted driving information from the safety system, and when a possible crisis is detected, a warning signal can be issued in a timely manner, even Can intervene in the control of the car. Adaptive Cruise Control (ACC) is one such system. Its main function is to decelerate the vehicle when the distance is too close, and then accelerate the car when the distance is far enough.

The adaptive cruise control system is an automatic speed control function for forward driving. It only partially interferes with the brakes, so that the driver is still in the position of the master. The first task to achieve adaptive cruise control is to lock the target vehicle in front, and then calculate the movement information of the vehicle in front, such as vehicle speed, acceleration, yaw rate, etc.; ACC system will calculate the distance and relative speed, and the owner The set reaction time further calculates the safety distance between the two vehicles and further accelerates and decelerates. When the distance between the two cars is too close, it switches to the processing mode of the pre-collision.

Driving warning system uses CCD/CMOS

In addition to the control of collision and vehicle speed, the driver's various behaviors can also be monitored and alerted by various sensing systems. These alerting features include Lane Departure Warning (LDW), driving hazard warning, visual dead zone warning (or blind spot detection), and more. Most of these functions are monitored by CCD/CMOS image sensors, and a set of identification systems is used to determine whether the vehicle or driving behavior is normal, and appropriate warning signals are issued in due course.

The lane departure warning is to perform an alert action when the vehicle does not normally deviate from the lane line, the assisting driver controls the vehicle to remain in the lane line, or reminds the driver to change the lane must first hit the direction light. If the driver touches the direction light before changing the lane, this is normal behavior and the system will not give a warning signal.

The driving hazard warning system uses an image sensor to monitor the driver's behavior. When the driver appears to be dozing off or the line of sight deviates from the lane for too long, a warning is issued. Some systems even monitor the alcohol concentration in the driver's seat and provide appropriate warnings. In addition, the driver's line of sight also has a lot of dead ends. By installing the rear side dead angle and the rear dead angle monitor, the driver can provide relevant environmental information about the visual dead angle. For example, using CCD or ultrasonic waves for monitoring, imaging and warning of rear objects can avoid accidents when the vehicle is reversing.

For the driver, useful information can alleviate some of the manipulation burden of manipulation and assist him in making appropriate response actions, but if the warning message appears too frequently and does not have much effect (such as "pre-speed camera" Voice warnings), this only makes the driver feel uncomfortable and refuses to use such an auxiliary system. Another issue is how to alert the driver, such as voice, screen/dashboard display, or alert the driver by vibrating the accelerator pedal, steering wheel or body motion.

Active safety systems require high sensors

The key to making correct warnings or even system monitoring is the full and useful sensing information, as well as the ability to identify or judge information. The former relies on a wide range of sensors, while the latter relies on reliable algorithms in the controller. In terms of sensors, current technologies for environmental sensing include radar, light detection and ranging, infrared, ultrasonic, image sensors, and accelerometers. Each of these technologies has its own characteristics of use, and is suitable for different locations and different applications in the vehicle body.

In order to follow the front car and the pre-collision function, the millimeter wave radar or laser radar is mainly used on the sensor. Among them, the cost of laser radar is relatively low, about 1/3 of the millimeter wave radar. However, due to the relatively short wavelength of the laser radar, it is impossible to achieve the desired function in rainy days. Therefore, in order to improve safety performance, high-end vehicles will still be used. Millimeter wave radar.

In terms of identification of pedestrians, roads, obstacles, and visual field assistance, infrared and image sensors are the main monitor technologies. The infrared monitor is divided into two technologies: far infrared (FIR) and near infrared (NIR). The principle of far infrared is to detect the heat of the object and then visualize the temperature difference, which is suitable for monitoring human bodies and animals with body temperature; The ability of night vision can help display the road ahead in the poor visibility environment (such as at night), and can display a position farther than the headlights, but it will be affected by the front control lights.

The application of CCD or CMOS image sensors is also becoming more and more extensive, and the auxiliary line of sight application from the front, front side and rear has been expanded to monitor the inside and the rear of the vehicle. Through identification logic, it can be used to identify road dividers, pedestrians, traffic signals, or to determine whether the road surface is dry or accumulated, snow, and even further speculate the wetness of the road for the driver to make reference. For high-contrast or dark environments, the image sensor can also produce a more distinct tone by combining high-sensitivity and low-sensitivity images.

In addition, the image sensor can be combined with infrared or radar to form a hybrid sensor that provides more powerful monitoring and alerting functions. In the case of an infrared monitor, when the infrared rays reflected from the front of the infrared LED are absorbed by the CCD, the road conditions around the vehicle can be recognized regardless of day or night.

The more intelligent active safety system is realized by various sensors that are accurate and distributed throughout the vehicle and outside, as well as a calculation platform with correct and immediate identification and judgment capabilities. Visual sensors (such as radar, infrared, image sensors, etc.) are just a few of the many sensors. Future automotive safety systems must fully integrate gyroscopes, accelerometers, steering wheel and brake pedal position detectors, and tire speed detection systems. , to accurately monitor and alert the car body parts.

More and more sensors, more powerful computing centers, and controls on brakes, engines, airbags, etc., will create a more complex in-vehicle network that requires more real-time processing performance and data. Transfer capability. These intelligent accessibility features will make it easier for drivers to drive and safely, and also help reduce traffic accidents or reduce the severity of the incident.