The latest development direction of train stabilit

2022-09-27
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Vehicle stability brings confidence to extruder enterprises. ABS development direction

automobile anti lock braking system (ABS) is an important way to improve and improve the braking performance of automobiles. It can give full play to the potential adhesion between tires and roads, and improve the braking performance of automobiles to the greatest extent to meet the needs of driving safety. It has always been the goal of people. Although the theoretical basis of ABS has long been established in the electronic information and electrical industry, in view of the limitations of related industries such as electronic technology, reliability and price-benefit ratio have become two major obstacles in the development of ABS. Since the 1980s, due to the development of electronic technology, the reliability of ABS has been improved, and the improvement of vehicle driving speed, resulting in wheel locking and slipping during braking, which has become one of the major hidden dangers of driving safety. In order to improve braking performance and ensure driving safety, ABS has been widely used

in 2005, the domestic demand for ABS was 1.26 million sets

all developed countries in the world put forward mandatory requirements for vehicle safety. In the 1990s, Europe, the United States, Japan and other developed countries formulated strict regulations to improve vehicle safety. Facts have proved that the development of ABS is closely related to national automobile safety regulations. In 1995, the ABS installation rate of North American cars reached 70%, and that of European cars was about 40%. At present, ABS has become the standard equipment for the production of cars in these countries

in the national compulsory standard gb-12676 "structure, performance and test methods of automobile braking system" formulated by China in 1999, the installation of ABS has been regarded as a compulsory regulation. By 2005, the ABS loading rate of domestic vehicles will reach 50%. The loading rate of micro cars and passenger cars is 20%, which means that the demand for hydraulic braking ABS will reach 750000-810000 sets; The loading rate of ABS for medium and heavy trucks and large and medium passenger cars is 100%; The demand for air braking ABS is 350000-450000 sets; Thus, by 2005, the total domestic demand for ABS was 1.08 million-1.26 million sets

ABS products in China are in the initial stage, and the promotion threshold of pneumatic ABS is lower than that of hydraulic ABS. On the one hand, pneumatic ABS is mainly for heavy vehicles and buses, which are mainly produced in China, and national mandatory regulations do not require these vehicles to be equipped with ABS system. Domestic research and development in this area started earlier and has a good technical foundation. Hydraulic ABS is mainly aimed at cars, while most domestic cars are joint ventures, and its technical voice is mainly controlled by foreign parties, so it will be more difficult for domestic ABS system to enter the field of cars

at present, it is estimated that there are about 10-20 domestic ABS manufacturers, which generally only do pneumatic or hydraulic ABS, and few pneumatic and hydraulic ABS are developed at the same time. For pneumatic ABS, foreign manufacturers are mainly German WABCO and Knorr, whose market is estimated to account for about 80%. Although there are many domestic manufacturers, there is no large-scale supply. Hydraulic ABS is mainly made up of continental Germany, Bosch, TRW and Delphi. Domestic manufacturers are weaker and have basically not formed large-scale production. However, in recent years, domestic enterprises have seen a good market prospect and have invested in accelerating development and production

abs system technology is gradually upgraded

abs system involves the following technologies: first, sensors. Traditionally, ABS sensors are mainly electromagnetic sensors. At present, 90% of the domestic market is dominated by this kind of sensor, and almost 100% of pneumatic ABS adopts this kind of sensor. This kind of sensor has the advantages of low cost and strong ability to resist harsh environment, but the disadvantage is that the working gap is required to be small, and there is often no signal at low speed. In recent years, due to the development of semiconductor technology, Hall sensors have been gradually adopted in hydraulic ABS system. Its characteristics are small size, large working gap, signal amplitude independent of speed, and it can also test gap and direction, especially for ABS upgrading products. Therefore, Hall sensors show a gradual increase trend

the second is ABS controller. At present, the ABS controller is mainly based on 16 bit single chip microcomputer, which generally adopts dual CPU, and some adopt single CPU. The major foreign semiconductor manufacturers have mature solutions for all kinds of hardware chips used, so the hardware implementation has been relatively simple

ecu hardware is mainly developing in the direction of integration. Some companies use advanced semiconductor technology to try to integrate power drive chips with CPU, and integrate various auxiliary functions, such as power supply and communication. In this way, the chip can be integrated into oneortwo devices, which greatly improves the reliability of the system. In terms of software, some people also try to standardize ABS software, and the software development is developing towards graphics and automatic code generation, which will lead to higher CPU computing speed and larger memory and program storage space

abs mainly adopts can as the communication bus

the on-board network mainly has three levels: A, B and C. class A is mainly electronic, and its representative bus is Lin. Level C is mainly based on real-time control, and its representative bus is can. ABS mainly adopts can as the communication bus, pneumatic ABS mainly adopts SAEJ1939 as the network protocol, and hydraulic ABS is generally formulated by each manufacturer. The general ABS communication rate is 500 baud. ABS is a safety system, so it generally sends the comprehensive enhanced information of ABS status, wheel speed and other resource environment and energy constraints to the bus. The system with ASR also controls the driving force through the bus

with the development of brake by wire, the bus speed and reliability are required to be greatly improved. At present, there are buses with 1m baud rate to 10m baud rate, which are ttp/c, TTCAN and FlexRay respectively. Each bus has its own characteristics. At present, no bus has entered the practical stage, and the price and fault tolerance of the system are the main problems. In addition, the brake by wire system has not yet entered the stage of mass use, so the emergence of this kind of high-speed bus will take time

the other part of the on-board network is the diagnostic protocol. In the early days, ISO9141 was generally used as the hardware standard, and the application layer protocol was determined by the manufacturer. The current trend is to continue the hardware interface of ISO9141, and the application layer protocol adopts isokw2000

electronic braking will be the development direction

abs technology to formulate personalized service strategies based on the needs of different customer groups has matured in the early 1990s, and there has been no breakthrough development in the past decade, but the expansion of ABS technology has greatly improved the connotation of ABS. The initial expansion of ABS is the anti-skid control system, which is divided into braking anti-skid (EDS) and driving anti-skid (TCS), including

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