天敏d6附录
附录A
外文
Technology Features Reasearch of Japanese Railway Signal System
This paper begins with the developing history and technical classification of railway transportation, introduces the railway control system used in Japan, analyzes its technology features respectively from the aspects of electronic, computer and communication technology, and at last proposes the technical developing direction of future train control system.
1、Introduction
In the early days of railways, there was no signaling system. A station attendant showed the signal of go or stop by gestures. But people would make some mistakes which caused accidents.
Signaling system prevents the accidents efficiently. Early signal system in Japan was Automatic Traffic Stop (ATS) devices. This device could automatically stop the train when it received the stop signal. Eve
n if the driver ignored the alarm of the train-borne stop device, the device on the track could stop the train automatically.
ATS-P (Automatic Train Stop Protection) was developed to raise efficiency. Using the responder to send a receive data signal, ATS-P system transmits information of the distance about the next stop to the train via the track, and then the system generates a train speed-checking pattern with these information.
ATC (Automatic Train Control) system is developed to resolve problems of ATS-P. In ATC system, safety operation procedure will be activated to guarantee the safe performance of the train when the train operator made mistakes.
To meet the needs of the modern massive high-efficient transportation, new traffic control systems are emerging such as ATACS (Advanced Train Administration Communication System), CBTC (Communication Based Train Control), etc. With the integration of railway signal and communication technology, track structure of new pattern and additional train-borne functions.
This paper proposes the features of the current railway control system in Japan with the development history of the railway signal system as background, and then
shows its key technology and developments in future.
2、Railway Signal Systems
The first railway transportation system began to operate in 1830 between Liverpool and Manchester. Signal system was introduced to improve safety and to cope with the increase of traffic volume.
In 1841, the signal technology was used at the two ends of the North Midland tunnel at the first time. The track circuit for the train detecting was invented in 1872.
The following will analyze typical railway signal system developed by Japan National Railways (JNR) and East Japan Railway. For these systems, the level is determined by fixed block or moving block system. Train position locating is taken by the track circuit or onboard train locating device. The information is transmitted through the track circuit or radio.
(ATS-S)system (Kera, 2000 is automatic train stop device which was introduced into JNR to prevent train collision. In a block section where a train is present, a track circuit detects the train position information, and the control device turns the signal for the section to Red. This status indicates that no other train can go into this block section. All of the other trains must stop before the section. Sign
als of other sections, into which a train can go, are Green or Yellow. Permitted speed is determined according to the distance to the section with the red signal. There is important relationship between the signal status of a section and the train position. The block system used in ATS which is consisted of the track circuit and signal device is based on the fixed block section. ATS-P improved to correct a weakness of ATS-S. By using digital information from a transponder, ATS-P transmits information about signal aspects and the distance to the next stop signal from the trackside to the train and uses this information to generate the train speed checking pattern. Then the computer compares the actual speed and this pattern. If the actual speed exceeds the pattern speed, the braking system will start. Different from ATS-S, ATS-P won t require the driver verify. When the train speed approaches the danger pattern, it will alarm the driver. The system engages the service brake at maximum power automatically when the speed pattern approaches the danger pattern.
D (Decentralized)-ATC is an intelligent on-board system. Every train calculates its appropriate permitted speed according to the stop position information from the ATC central logic system. In high traffic density braking on time can be realized by pattern control. The cost of ground devices is reduced by using general
information equipment and a decentralized system. The system contains the flexibility of be able to s
horten the train headway without changing ground equipment when rolling stock performance is improved. Operability is improved by indicating the train usage on routes to drivers.
Along with information technology develops so rapidly, a new railway traffic control system appears. The system can make trains know its own position information and the distance with others. The developing system is called ATACS (advanced train administer and communication system).ATACS is a new rail control system based on information technology and ADS technology.
3、Technology Features of Japanese Railway Signal System
Decentralized Technology Feature
仙剑奇侠传四秘籍At first ATC was used for supporting the safety supers-peed system of the Japanese Shinkansen, and then was introduced to traditional rail system to shorten the distance between trains. But it can’t work effectively because of the ATC technology limit. In this background D-ATC (data decentralized ATC) based on ADS (autonomous and decentralized system) developed as the level 2 system. In D-ATC system every train is allowed to calculate its own speed. JR East developed a kind of Shinkansen D-ATC, in which data communication was used. The D-ATC is officially called DS-ATC. The system is used on Keihin-Tohoku line called D-ATC, while in Shinkansen called DS-ATC.
In the ATC system the speed signal is in the drivers cab, which received permitted speed information from the ground equipment continuously. ATC s central logic system transmits ATC signals to track circuit. ATC signals are about speed information, while they are used as train detection signals. The logic device can determine the section on which a train is present by monitoring the level of received ATC signal power because the wheels of the train short the track circuits. To set the rack circuit boundary and speed pattern is to sustain train s headway, which is necessary for train traffic control. In the ATC system the central logic system undertakes the most train interval control. The on-board system controls the braking system according to the instructions from the central logic system.
Distance between trains is an important concept in railway transportation control. In this control method the system recognizes the distance between two consecutive trains firstly. Then the system controls their speed to insure a safe distance. In order to realize this distance control, various new functions are required,
such as positioning exactly,high speed communication between trains and ground devices.
The major difference between D-ATC and traditional ATC lies on that D-ATC is an intelligent on-board system. Every train calculates its appropriate permitted speed according to the stop position information from the ATC central logic system. Administer and Communication Technology Feature
There is one point to stop one train before it crashes the preceding train. That is just to control critical stop distance. And the key information is the exact train position and where the train should stop. We know the ATC service purpose so that the basic functions of new ATC are clear. In another word equipment on the ground only transmits the train stop information, and then the train itself confirms its position and calculates the distance between it and the stop position. After that the train takes the radian and gradient into account and brakes at the proper moment.
Ideal distance control model consists of trains which know each others positions. The model realized because of wireless communication technology development.
In railway an area is divided into several control areas, in which ground devices and radio base stations are set up. Ground devices in every control area have many functions, such as train positioning, distance control, switching control, level crossing control and security for maintenance. Radio base stations and on-board equipment exchange information. As the appropriate interval between stations is determined according to the service area covered by radio transmissions, every base station is connected with corresponding ground control devices.
The on-board computer controls brakes according to the control information from the ground devices,
长沙人 while it sends out the train position information to the ground equipment through on-board mobile radio base station. The first step of the control procedure is to determine the accurate train position as measured by the on-board computer. When a train enters or gets out of the boundary of a section, its original position will be recorded. Then on-board computers detect the trains speed and deal with the speed information. So the train s position track is obtained. However, when a train passes a position device on the ground, its position information will be corrected.
The position detected by the system is structured into the identification numbers of the ground controller in the relevant control area, the virtual blocks into which the
control area is divided, and the position within the relevant track block, and these data are processed both by the wayside and on-board computer.
According to the transmitting distance restricts of radio signals, generally two base stations are constructed three miles apart. Four different frequencies are used alternately to prevent two neighbor base stations signals from interfering. For on-board system operation the practically used frequency is the most proper one of all ground radio base station in every area. Every base station must connect with trains passing it. Generally we presume that the base station communicates each
train in one-second cycle. Accordingly, one-second is divided into several time slots. Because there will be mistakes in communication, space difference system and Reed-Solomoncode are adopted. Reed-Solomon code can correct early errors.
ATACS is based on ADS (Autonomous Decentralized System) technology. In ATACS system ground devices are decentralized and connected by a network. According to the information from ground equipment the permitted speed is generated. Every trainson-board equipment can control the braking system automatically. Ground system is composed of central control system and train control system. The system is provided to devices autonomously. The advantage is that it reduces disable devices influence to whole system. What s more, it makes it possible to set up a system step by step. If one base station is out of work, an adjacent base station takes charge of its work. So the whole system can go on working.
4、Conclusion
The results of the research shows that new train control systems will be developed by applying the latest information and control technology in place of the conventional signaling system applied for over 100 years. The future autonomous train control systems will consist of an on-board system only, 三岁孩子的教育
without a ground system, because of the application of the ADS technology. ADS technology information technology and communication technology is the key to realize the future train control system.
五一劳动节手抄报资料安徒生童话简介中文译文
版权声明：本站内容均来自互联网，仅供演示用，请勿用于商业和其他非法用途。如果侵犯了您的权益请与我们联系QQ:729038198，我们将在24小时内删除。
发表评论