People can rely on hand, eyes, ears to perceive the external information, and the sensor is the object of the hand (pressure sensor), eyes (camera), ears (speakers). Traditional car, because it is human control, perception of the external environment Know and control of the car are done by the driver. Or some slightly advanced cars, equipped with advanced aided driving, by the driver Sensor and auxiliary driving system with the completion of these 'tasks.' But for autopilot and unmanned vehicles, because the vehicle itself occupies part of the car or even all the control, then have to rely on the installation of a variety of sensors in the car to work together to ensure traffic safety.
Automatically driving the car's sensors are: image sensors, laser radar, millimeter-wave radar, ultrasonic radar and biosensors. They are based on their own different product attributes, in the process of driving the car driving the main function of the main to ensure the normal operation of the car.
Image sensor in the automatic driving car is a basic part of the class, access to images, the early need to use with the digital camera, the latter need to support the image data processing system, can provide intuitive, real visual image information. Used in car vision systems such Suction Control Valve as reversing images, front view, overhead, panoramic parking images, mirror replacement, driving recorder, forward collision warning, lane departure warning, traffic signal identification, pedestrian detection, adaptive cruise control, Blind spot detection and night vision, etc., to ensure that the visual system in a variety of weather conditions, can clearly identify the lane line, vehicles, obstacles, traffic signs and so on.
Lidar is one of the most widely used sensors in the automatic driving vehicle. It mainly measures the position and velocity of the target by transmitting the laser beam to the target object and receiving the laser beam reflected from the target object, and sensing the surrounding environment of the vehicle , And the formation of precision up to centimeters of the 3D environment map for the next step in the establishment of vehicle control decision-making basis. Detection range is wider, detection accuracy is higher. However, the shortcomings Temperature Sensor of the lidar is also very obvious: in the rain and snow and other extreme weather performance is poor, the amount of data collected is too large, very expensive. In particular, the number of laser radar harness directly related to the measurement accuracy, the more wiring harness, the more accurate measurement, but the price is also more expensive.
Millimeter-wave radar is also a mainstream sensor now used in autopilot ADAS systems. Its wavelength is between the centimeter wave and the light wave, the short wavelength, the frequency bandwidth, has the ability to penetrate the fog, the smoke, the dust ability, may work all day, the compact size, the recognition the high precision, can help the automatic driving vehicle accurately ' See 'to the distance between the nearby vehicles, so as to provide drivers ABS Sensor with lane support, autonomous control speed, collision warning and other help to improve driving comfort and reduce the incidence of accidents. And the price, the millimeter-wave radar unit price is much lower than the lidar, is a relatively easy to get the sensor technology.
In the Tesla equipment autopilot kit, also used in the camera, ultrasonic radar and millimeter-wave radar three sensors. Among them, the ultrasonic is mainly used for parking ranging, auxiliary brakes, etc., shorter range. When using ultrasonic radar rangefinder, the ultrasonic transmitter first emits an ultrasonic signal in one direction to the outside, starts to be timed at the same time Throttle Position Sensor as the ultrasonic wave is emitted. Ultrasound is propagated through the air, and the obstacle will be reflected back immediately. The receiver stops counting immediately upon receipt of the reflected wave. The timer can measure the distance from the launch point to the obstacle by recording the time.
Biosensor sensor object is the human body characteristics, and the human body features can not be copied the uniqueness, it can be said that many other methods can better ensure traffic safety, but also the liberation of the driver's hands, increase driving pleasure.
Sensors are the main equipment in the Internet of information Pressure Switch to obtain information, the use of various mechanisms will be measured information into electrical signals, and then by the corresponding signal processing device for processing, resulting in a response. The sensor plays a sensory role in the object, is the way to get information, is called the Internet of things hardware cells. The Internet of Things vigorously promote and the wide application of intelligent terminals, so that a substantial increase in demand for sensor products.