We all know that people look at the road by their eyes, what about the unmanned car? In fact, the laser radar is the "eye" of the unmanned vehicle. What about the details? Let's take a look at it together.
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With the landing of autonomous driving, the laser radar, which was mainly used for three-dimensional scanning, has become an essential part of autonomous driving, and even determines the evolution level of the autonomous driving industry. However, in this area where the industry is critical, there is almost no right to speak in domestic products.
Lidar is irreplaceable
Lidar is a sensor that comes with a light source that actively emits laser light to sense the surrounding environment, like a bat positioning through ultrasound.
According to the level of automatic driving L1 - L5, L3 and below are auxiliary driving or low-level automatic driving, L4, L5 can be regarded as high-level automatic driving or even driverless. The current autonomous driving is in the L3 stage, the millimeter wave radar and even the camera can meet the visual needs of the car, and Tesla applies the former. However, in order to develop to a high-level automatic driving stage, laser radar is irreplaceable due to the influence of ranging, resolution, accuracy, and comprehensive information.
Lidar can accurately measure distance: by taking the time when the laser hits the object and returns to the receiver, multiply by the speed of light. Since each beam of light has relative position information, the laser radar can use the algorithm to generate high-definition digital maps of the surrounding environment of the car in real time for target tracking and recognition. Zhang Zhiwu, general manager of the domestic mainstream laser radar company, North Science and Technology, told the Science and Technology Daily reporter that the laser radar has high scanning accuracy and no distortion. The millimeter wave radar only knows that there are obstacles in front and cannot accurately describe the size and shape.
Laser data is vector data. Computers can classify, extract, and process, and automatically identify lane lines, block pillars, traffic signs, trees, etc., which other sensors can't.
Lidars are often distinguished by line count and are usually designed to be exponential at 2, such as 4-wire, 8-wire, 16-wire, 32-wire, 64-wire, and the 128-line top-of-the-line test products. The number of lines refers to the number of laser emitting sources, 16 lines of products have 16 sources, and so on. Among the self-driving cars that can currently be on the road, all those involved in laser radar use almost all of the products of Velodyne in the United States. Founded in 1983, the company is located in Silicon Valley and its laser radar products are standard in the industry, accounting for more than 80% of the market.
"Chip" can reduce the price
The number of lines determines the resolution of the lidar. The laser radar works in a rotating scan mode. A light source sweeps a circle and gets a 360-degree horizontal circular line of sight. This is why the “big flower pot†of the unmanned roof is constantly rotating. The more light sources, the denser the line of sight, the higher the resolution of the real-time map. Zhang Zhiwu uses the sketch analogy: the sketch is composed of lines, the denser the lines, the clearer the painting.
The earliest domestic 16-line products were launched in 2016 and currently have a maximum of 40 lines.
Manufacturing multi-line laser radar, domestic manufacturers generally face the cumbersome process. Increasing the number of laser radar lines in the traditional way is like splicing an increasingly wider radiator, resulting in a multiplication of product volume and greatly increasing the difficulty of mass production. According to Jin Yuanhao, CEO of Lidar Enterprise Drinking Ice Technology: "
Under the existing process conditions, increasing the number of lines requires an increase in the number of printed circuit boards, and the volume of the laser radar will also increase significantly. Both scale and integration must be balanced. â€
The reason why foreign manufacturers can make 64 or even 128 lines of laser radar, the chipping of internal components plays a decisive role: reducing the size of the laser radar, reducing heat dissipation, and helping mass production.
This requires a dedicated chip with large capacity, fast transmission speed, and efficient information processing. At present, domestic laser radar companies generally purchase German osram transmitters. In this regard, domestic intelligent car research expert Huang Wuling emphasized that "core chips, especially transmitters and detectors, need to be improved in terms of localization and anti-interference."
Unlike mobile phone chips, the receiving chip does not pursue the largest number of transistors per unit area, but has higher requirements for resolution. The original demand is small, tens of thousands of pieces a year. In the past two years, the vents suddenly turned to high-resolution high-quality sensors. The receiving chip production process is immature and the technical ability is insufficient. "The reception of laser signals requires a high degree of integration. Originally, a 1×1 single-point sensor was used. Now the car has a high resolution requirement of 1064×768.†Jin Yuanhao said. The production of this resolution according to the independent process is equivalent to the size of the front windshield of a half car, which is unrealistic to use. Therefore, domestic products are catching up with chips with less high resolution.
Independent research and development for the mass production market
Domestic research institutes and laser radar manufacturers are independently developing transmitter chips and receiver chips, but they are all in the initial stage, and the products have not yet been finalized. "Car-mounted laser radar is a niche industry. In recent years, with the development of domestic L2-class autonomous driving, there is a market, the industry has insufficient technical reserves, and insufficient human input." Jin Yuanhao said. His company is doing the 16-line lidar's launch chip, but it is also using low-priced products to grab market share.
The number of lines is the same, and the effects of different products are not the same. According to Jin Yuanhao, parameters such as accuracy, stability, and resolution are different from mainstream products. In particular, the stability of domestic laser radar is relatively insufficient, and the automotive industry has extremely high requirements for safety. The test time is long, and the market is not big enough to make it difficult to trace the Chinese goods.
Lidar is expensive, one is necessary, and the second is tight. This is a complete market for the seller. The price of the Velodyne 16-line product is still 4,000 US dollars after the price is halved at the beginning of the year. The 64-line product (also the most advanced in the market) of the Baidu smart car is about 80,000 US dollars, which is more expensive than the average car. The price is a roadblock for mass production and commercialization of unmanned vehicles.
For this reason, domestic laser radars have to tackle the problem. According to Zhang Zhiwu, the 16-line product of Beike Tiantian sold for 50,000 yuan last year, less than 30,000 yuan this year, which is equivalent to the discount of the Velodyne 16 line. "Once it is made, the price will be lost." Beyond the bargaining space, once the automatic driving goes from testing to mass production, the laser radar market is huge, and domestic products cannot be handed over.
New technical solutions are also emerging. "Lidar is developing in the direction of solid-state, and domestic manufacturers need to seize new directions and develop in parallel with their foreign counterparts," Huang Wuling said. Compared to the traditional 360-degree mechanical rotating laser radar, solid-state laser radar is a revolutionary technology that reads and writes data based on electronic components and removes mechanical rotating parts. On this new track, domestic manufacturers can stand on the same starting line with their foreign counterparts.
1 PCB Screw Terminal Block 2 Plug-in Terminal Block 3 PCB Spring Terminal Block 4 Barrier Terminal Block 5 Feed Through Terminal Block.
Terminal block consists of fixed terminal block (hereinafter referred to as socket) and free terminal block (hereinafter referred to as plug). The socket is fixed on the electric parts through its square (round) plate (welding method is also adopted for some), the plug is generally connected with the cable, and the plug and socket are connected by connecting nuts.
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Terminal Block Series
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