The reverse aid system (ParkingAssistSystem) informed in the form of visual images, sound position of the driver’s vehicle relative to the obstacle, release problems caused by mirror blind spots, so as to provide convenience for the driver to reverse parking, eliminate hidden dangers. And more generally in the mid-size car models will be configured, parking assist system is not a mystery, as long as the DVD navigation host or hosts with AV input, can be realized. Usually visual reversing car special systems require relatively high water level, the image sensor, the signal format, the effective pixel horizontal resolution, angle, and other parameters have opposite illumination numerical requirements, of course, reversing the image more clear accurate.
1. The parking assist system function
1, automaticity
After the installation of cameras, linked into the R range, if the hardware connection is no problem, the screen after the picture is automatically cut into the rear view, the real-time dynamic monitoring vehicle environment. Sweeping obstacles behind the car.
2, anti-fog
easy fog, mirrorObscured by fog, but is a special car camera HD, waterproof, fog, high sensitivity and infrared night vision five advantages, even in the fog can be high-definition display screen after the car.
3, night vision function
infrared night vision camera having a function of reversing the screen at night can also achieve the effect HD.
2. Parking assistance system Category
different reverse aid system sensors can be divided into an infrared type, an ultrasonic type, electromagnetic induction type, and ultrasonic type fitting with four kinds of machine vision.
1. Infrared formula
The parking assist system is made to transmit and receive infrared principles of 80s. The biggest drawback is its infrared susceptible to interference, additionally to the dark reaction of the roughened surface of the object insensitive. Worse, as long as an infrared transmitter or receiver surface a thin layer of snow or dust on the cover, the system will fail.
2. The electromagnetic induction type
Then, the parking assist system appears to be made of the principle of electromagnetic induction. Improve the detection sensitivity and stability than many infrared, but also has a fatal drawback, it can only detect moving obstacles. That is, when the vehicle is stopped, it can not detect anything. Therefore, practicality is also unsatisfactory.
3. The ultrasonic machine vision fit with
the latest reverse aid system as machine vision and ultrasonic detection means, all intelligentParking. For example, Lexus LS460L is the first to enter the domestic models have Intelligent Parking Assist system, which uses ultrasonic sensors to detect obstacles, and can be combined with the camera automatically recognizes the stop line, automatically detects when the car is good parking position and distance, as long as the driver press the confirmation key, the system will automatically parking.
4. ultrasonic
ultrasonic parking assist system mature technology, good stability, sensitivity, economical than the conventional parking assist system. 1990s, the parking assist systems finally ushered in technological breakthroughs, as adopted by the ultrasonic detection medium. Ultrasonic wave transmitting and receiving device, commonly known as the probe, has three main components: aluminum alloy, a ceramic diaphragm plate, the sound absorbing material.
The working principle is, after the microprocessor issues a command, vibrating tiles, form an ultrasonic resonance with the aluminum shell, around and fired. And around the rear sound wave is not required, the sound absorbing material to be added to reduce such interference. Ultrasonic wave launched, collides with an obstacle, the formation of echoes, an echo of this also happens in the form of vibrations received by the aluminum shell with the same tile.
microprocessor to calculate the difference between the echo time difference azimuth position of the obstacle is determined manner. The disadvantage is: barrier properties, acoustic wave itself, will lead to not detect certain obstacles. When the obstacle is too small and the wire rope lines thin object, when the object is an obstacle to snow absorbent cotton or the like ultrasonic waves, when the obstacle is the edge of a sharp object, parking assist system is very likely not be detected.
blind, ultrasonic parking assist system of the detector mounted on the rear bumper, in general, the center point of the probe 10 ~ 15cm or less ignored by the probe obstacle, and the obstacle near the parking space from the distance, this value will also become larger, increased risk. Thus, low bollard conical, stepped, cliff, a high portion of the object hanging from the corner, high curbs or protruding objects may not be detected; Goukan the class, the pit of the road pavement, it is helpless .
3. The parking assist system considerations
1, ultrasonic sensors detect obstacles in the blind spot, this time can only be avoided by observing the accident occurred to the parking.
2, the ultrasonic sensor can not always detect children and animals.
3, the parking may be less than such detection distance control towing hook, bar fine, fencing posts and other obstacles, and fine, to guard against accidents.
4, the vehicle speed is lower than 15Km / h when the parking distance warning system should be operated.
5, to ensure the function of the rear bumper on the sensor, which shall be kept clean and to prevent freezing. Cleaning with high pressure cleaning Park Distance sensor system should be short gently, holding the sensor with the nozzle at least 10cm of distance.
6, if your vehicle is equipped original towing bracket traction trailer, the reverse gear is engaged, the system automatically stops the alarm.
7, the probe icing, clogged with mud, snow, covering the moisture probe, Park Distance Control system will also be used as an obstacle.
4. History reversing aid system development
With the economic take-off and improve the people’s living standards, more and more families are now currently use the car. According to statistics, as of the end of 2009, China’s civil vehicle population reached 76.19 million, of which private car ownership has reached 26.05 million, and this number will continue to grow. In this context, more and more new drivers on the road, the city’s parking space has become increasingly crowded.