1、 畢業(yè)設(shè)計(jì)中英文翻譯 機(jī)電工程學(xué)院 學(xué)生姓名： 學(xué)號(hào)： 探測(cè)制導(dǎo)與控制技術(shù)學(xué) 院： 專 業(yè)： 指導(dǎo)教師： 2012年 6月HighSpeed Data Acquisition System Based on ARM & Linear-CCDDong Jianjun Zhao XiaojinDept. Four, The First Aeronautical Technical College of the Air Force Xinyang 464000.China.Abstract : This paper presents a high speed acquisition system o

2、f linear-CCD based on ARM, high-speed linear-CCD and high-speed ADC are selected. As the sampling speed of A/D is slower than the working clock frequency of ARM, CPLD and FIFO are used as I/O between A/D and ARM. It makes the circuit works harmonious, simple and easy controlling, and also increases

3、the efficiency of ARM. In order to increase the communication speed, the Universal Serial Bus (USB) technology is adopted to communicate with the PC. ARM is the key processor utilized to control the data sampling, data compute and data transfer. As a result, the whole system works effective. The sys

4、tem can be applied to the high speed data acquisition and operation situations from multi-channel analog signals. Key Words : ARM; Linear CCD; Contact-line; Pantograph; Stagger value I. Introduction In electrification railways, in order to extend the life of the pantograph on electric locomotives, s

5、o that the slider of pantograph wear evenly, the contact-line (electrified railway power feed line) in straight-line segments is arranged as zigzag route (curve section arranged in the form of polyline). The distance between the contact-line of positioning point and the pantograph centerline track i

6、s called out stagger-value, which is a key indicator of contact-line .Stagger-value can not be ignored, the value too small will affect the slider of pantograph wear evenly and the purpose of extending using life; otherwise, in some cases (such as caught in a stiff winds), cause a large range of lat

7、eral movement of the roof (and the higher the speed, the greater pantograph swing around), some parts of contact-line will be in excess of the effective work length of pantograph, so that the stagger-value of contact-line beyond the standard range, leading to deterioration of the current collection,

8、 and even cause incorrect running of the pantograph accident. Pantograph-catenary malfunction will result in interruption of train operation, which impact on rail transport seriously. In order to avoid these phenomena, the stagger-value and its changes should be tested regularly.Therefore, a locomot

9、ive contact-line monitoring system and its mating data acquisition system were developed, which calculate the instant stagger-value quickly.II. System Components System hardware components are shown in figure 1. The system consists of the following components: (1) using TOSHIBA Companys high-speed l

10、inear array CCD to achieve the digitization of contact-line images (CCD output the signal of corresponding time sequence of position); (2) using Atmel Companys AT91RM9200 processor of ARM9 series to realize digital signal acquisition and processing; (3) using PDIUSBD12 USB interface device to comple

11、te the data communications between measurement system and the PC. Due to the characteristics of its improved Harvard structure, special instructions and quick to realize a variety of signal processing, ARM processor is widely used in image processing, communications, radar, sonar, precision machiner

12、y fields, etc. ARM processor is adopted for its arithmetic speed and bus width. As the real-time signal analysis and calculation require a high speed of computing, Atmel Companys ARM chipAT91RM9200 is selected. The chip is ARM920T based, high-performance, low power consumption 16/32-bit RISC(reduced

13、 instruction set computer) microcontroller, which incorporates a rich set of application peripherals and provide a single-chip solution for industrial control applications that require a wide range of peripherals at low power consumption and strictly stable working. Fig 1 System block diagramIII. Re

14、al-time processing and transmission of CCD digital image In order to achieve real-time digital image transmission, several major factors which affect real-time transmission should be necessary to solve: First, the speed of linear array CCD data acquisition; Second, the transmission speed between lin

15、ear array CCD and ARM processor; the third is the data transmission speed between ARM processor and computer. The following will be described in detail. A. Linear array CCD acquisition speed Acquisition speed is a critical performance indicator for image sensor, TOSHIBA Companys TCD1209D linear arra

16、y CCD is used to meet the targets. Its clock pulse frequency can operate as high as 20MHz, especially suitable for high-speed conditions of size measurement and dynamic analysis.Fig 2 Linear CCD TCD1209D and its time sequence diagramLinear array CCD TCD1209D and its time sequence diagram are shown i

17、n figure 2. B.Transmission speed between CCD and ARM processor In order to improve the speed of CCD data acquisition and reduce conversion time, adopting high speed A/D converter can make it exchange data with ARM processor at high-speed. ADC08200, Analog Companys nanosecond conversion device is ado

18、pted. Its a single-channel, 8-bit A/D converter, which operates over a wide range of temperature, converts fast, operates at conversion rates up to 230 MSPS, thus achieving entire signal acquisition of linear array CCD. ADC08200 is shown in figure 3.Fig 3 High-speed A/D converter ADC080200FIFO is us

19、ed as a data buffer to co-ordinate the rate of ARM processor and ADC. It is a two-port (input and output port) memory for temporary storage of first in first out data. Due to the time to write data to FIFO is far less than the A/D conversion time, therefore, the acquisition speed depends on the A/D

20、conversion speed. In order to improve the speed of the entire measurement system, the time sequence of entire circuit is precisely controlled by the CPLD to make the circuit works harmonious. CCD driving signal, integration time control, address decoding, A/D conversion control, data buffer and data

21、 acquisition logic functions integrate in the CPLD, so that the entire circuit structure is simple and reliable. In order to further enhance the system speed, when the system starts, system programs are transferred to high-speed SRAM for running and SDRAM for data storage; SRAM, SDRAM should be plac

22、ed as close as possible to ARM processors, and the signal lines the shortest possible. ARM processor (AT91RM9200), the signal processing core of the entire hardware system, read the CCD light intensity signal from FIFO, calculate the distribution of contact-line image in the CCD with corresponding a

23、lgorithm, and transfer the result to the slave computer through USB. C. Transmission speed between ARM processor and computer In order to increase the speed of data transmission and reduce transmission delay, USB interface is used for data transmission. USB1.1 interface support low-speed and full-sp

24、eed transmission, data transfer rates has reached 1.5Mbps in low-speed mode, the transmission speed up to 12Mbps in full speed mode. Philips Companys PDIUSBD12 is adopted. When a USB device inserted into the PC, PC enumerates USB device automatically. When detecting equipment to insert, PC send quer

25、y request. USB devices respond to the request and send equipment Vendor ID and Product ID; PC loads the corresponding device driver with these two ID to complete the enumeration process. PC-side USB device driver is completed by WinDriver. Data communication between PC and USB equipment mainly inclu

26、des two aspects: first, read the sample data; second, send control commands to the acquisition system. IV. CCD image recognition algorithm ARM processor is mainly responsible for the solution of stagger-value; its the process of image identification, including background separation and feature extra

27、ction of the image data. Identification of the image is for image gray only; the standard deviation threshold tracking method is adopted. The image is composed of black-and-white texture, and gray-scale varies greatly, with a larger standard deviation; and background gray distribution is relatively

28、flat, with small standard deviation. Therefore, the standard deviation of each point as the center of a group of pixels is calculated, the value greater than a certain threshold determine the point in the foreground, or as the background. This system not only measures the contact-line instant positi

29、on, but also calculates the abrasion state of the contact-line to evaluate its life span. System support by associated PC software, through subsequent playback of the data collected, to check the situation of stagger-value, as well as the abrasion of contact-line, and decide whether to adjust and re

30、place or notV. Measures of improving system reliability High-speed data acquisition system is inevitably affected by interference from the external environment. As the complex environment around the measurement system, many factors interfere with the system. Electromagnetic interference around 27.5K

31、V high-voltage catenary affects great; the pantograph detaching will be accompanied by the emergence of arc sparks, this phenomenon interfere with communication line along the lines, accompanied by high-frequency electromagnetic waves, therefore, necessary anti-interference measures should be taken.

32、In order to improve the ability of anti-interference, anti-jamming measures taken are as follows: take anti-interference design of PCB circuit to reduce the external interference on system; all cables adopt shielded cable with wave-proof sleeve; equipment shell adopts shielding material and detectio

33、n window of the shell use gauze to isolate the interference. VI. Results We have used this highspeed data acquisition system in Wuhan south locomotive-depot to measure the contact-line instant position, and the test result shows that the whole system works effective, fast and high degree of accuracy

34、; exclude the vibration of the train and the contact-line, it reach the accuracy of 0.1mm. This design is flexible and corresponds with the actual needs. REFERENCES 1 Yu Wanju. Design and the Measurement Theory of Contact-line M, Beijing, China Railway Publishing House, 1991. 2 Zhu Feixiong. Detecti

35、on of Stitched catenary suspension J, Electric Railway, 2003,(1):15-17 3 Li Weimin, Xing Xiaozheng. Application of DSP in the Linear CCD measuring system J, Chinese Journal of Scientific Instrument, 2003,(2):183-185 4 Huang Zhengjin, Xu Jian. Introduction to CPLD system design and application techno

36、logy M, Beijing, Publishing House of Electronics Industry, 2002. 5 Cao Xiaowei. The principle and application of high-speed high-precision linear array CCD-TCD141C J, International Electronic Elements, 1997,(8):26-29 6 Bi Youming, Yang Tiemei. High-speed data acquisition and processing system for li

37、near CCD J, Journal of Taiyuan University of Science and Technology, 2000, (1): 31-33 7 Wang Ning, Shan Shengxiong. Analysis of the contact force between pantograph and catenary J, Electric Railway, 2000, (2): 22-24 8 Bai Dongliang. A new structure of the pantographSelf-detaching pantograph J, Elect

38、ric Drive for Locomotives, 1999, (6): 42-43 9 He Duyang, Huang Xiaodong, He Kui. The Width Measuring Instrument for Steel Plate by Linear CCD Technology. Technology and Test. 2007, 5:64-66. 10 Wang Qingyou, Zhang Kexin, Jin Gui, Liu Haijun. Design of linear CCD real-time test system based on DSP. El

39、ectronic Measurement Technology, 2007, 30(7): 85-86. 11 Zhong Hongtao, Duan Fajie, Wang Xueying, YE Shenghua. Design of CCD Driver on Auto-adjust Exposure Time. Chinese Journal of Sensors and Actuators.2006, 19(6):2256-2259. Dong JianJun, Master, Lector， The First Aeronautical Technical College of t

40、he Air Force. Xinyang 464000. China. Email: Zhao Xiaojin, Master, College of Mechanical and Electrical Engineering, Xian University of Architecture & Technology, Xian 710055.China. Email: 基于ARM與線性CCD的高速數(shù)據(jù)采集系統(tǒng)摘要本文介紹了一個(gè)基于ARM的線性CCD高速采集系統(tǒng)，系統(tǒng)中選擇了高速線性CCD和高速ADC。因?yàn)锳DC的采樣速度相對(duì)ARM的工作時(shí)鐘頻率較慢，所以使用CPLD和FIFO作為A/D和A

41、RM之間的I/O接口。它使電路工作在更加平穩(wěn)、簡(jiǎn)潔而易于控制，同時(shí)也提高了ARM的工作效率。為了提高通信速度，這里采用通用串行總線（USB）技術(shù)來與PC進(jìn)行通信。 ARM是用來控制主處理器的數(shù)據(jù)采集，數(shù)據(jù)的計(jì)算和數(shù)據(jù)傳輸。結(jié)果證明，整個(gè)系統(tǒng)能高效運(yùn)作。該系統(tǒng)可應(yīng)用于高速數(shù)據(jù)采集及多路模擬信號(hào)的工作環(huán)境下。關(guān)鍵詞：ARM；線性CCD；接觸線；受電弓；錯(cuò)開值1 引言在電氣化鐵路，為了擴(kuò)大對(duì)電力機(jī)車受電弓的壽命，所以要使受電弓滑塊磨損均勻，接觸線的直線段（電氣化鐵路供電線）排列為曲折路線（彎段被安排成折線的形式）。之間的接觸線的定位點(diǎn)和受電弓軌道中心線距離稱為錯(cuò)開值，這是一種接觸線的關(guān)鍵指標(biāo)。錯(cuò)開值

42、是不可忽視的，這個(gè)值過小會(huì)影響到受電弓滑塊磨損的均勻性，從而影響到延長(zhǎng)使用壽命的目的，然而，在某些情況下（比如陷入了激烈的風(fēng)中），造成大范圍的在屋部的橫向運(yùn)動(dòng)（并且速度越快，受電弓的左右擺動(dòng)越劇烈），接觸線將在某些部分將會(huì)超過受電弓的有效工作長(zhǎng)度，從而使錯(cuò)開，接觸線值超出標(biāo)準(zhǔn)范圍的錯(cuò)開值，導(dǎo)致了當(dāng)前連接的破壞，甚至導(dǎo)致了會(huì)產(chǎn)生受電弓事故的錯(cuò)誤運(yùn)行。受電弓與滑觸線發(fā)生故障，將導(dǎo)致列車正常運(yùn)行的中斷，從而對(duì)鐵路運(yùn)輸產(chǎn)生嚴(yán)重的影響。為了避免這些情況，錯(cuò)開值及其變化應(yīng)經(jīng)常性地予以測(cè)試。因此，一個(gè)機(jī)車的接觸線式在線監(jiān)測(cè)系統(tǒng)，及與其配套的數(shù)據(jù)采集系統(tǒng)被開發(fā)出來，它的工作是實(shí)時(shí)地、迅速地計(jì)算錯(cuò)開值。2 系統(tǒng)

43、組件系統(tǒng)硬件組成如圖1所示。該系統(tǒng)由下列部分組成：（1）采用東芝公司的高速線陣CCD實(shí)現(xiàn)接觸線影像的數(shù)字化（CCD輸出對(duì)應(yīng)的時(shí)間序列位置的信號(hào)），（2）采用Atmel公司ARM9系列處理器中的AT91RM9200，實(shí)現(xiàn)了數(shù)字信號(hào)的采集和處理；（3）采用PDIUSBD12的USB接口設(shè)備，完成測(cè)量系統(tǒng)與PC機(jī)之間的數(shù)據(jù)通訊。由于它改進(jìn)型的哈佛結(jié)構(gòu)，特殊的指令系統(tǒng)以及迅速實(shí)現(xiàn)各種信號(hào)處理的特點(diǎn)，ARM處理器被廣泛應(yīng)用于圖像處理，通信，雷達(dá)，聲納，精密機(jī)械等領(lǐng)域。ARM處理器正因其算術(shù)速度和總線寬度而被采用。隨著實(shí)時(shí)信號(hào)分析和計(jì)算都需要很快運(yùn)算速度，所以系統(tǒng)選擇了ATMEL公司的ARM芯片AT91R

44、M9200。該芯片是基于ARM920T的，高性能，低功耗的16/32位RISC（精簡(jiǎn)指令集計(jì)算機(jī)）微控制器，它集成了一套豐富的外圍設(shè)備的應(yīng)用，并在那些需要一大批外圍設(shè)備，并能在低功耗的外設(shè)和嚴(yán)格穩(wěn)定工作的工業(yè)控制應(yīng)用中，提供了一個(gè)單芯片的解決方案。圖1 系統(tǒng)硬件組成3 CCD數(shù)字圖像的實(shí)時(shí)處理與傳輸為了實(shí)現(xiàn)實(shí)時(shí)的數(shù)字圖像的傳輸，幾大影響實(shí)時(shí)傳輸?shù)囊蛩貞?yīng)該予以解決：第一，線陣CCD的數(shù)據(jù)采集速度；二是線陣CCD和ARM處理器之間的傳輸速度；第三是ARM處理器和計(jì)算機(jī)之間的數(shù)據(jù)傳輸速度。下面將給以詳細(xì)描述。A. 線陣CCD的采集速度采集速度對(duì)于圖像傳感器來說，是一個(gè)關(guān)鍵的性能指標(biāo)，這里采用東芝公司的TCD1209D線陣CCD來滿足目標(biāo)要求。它可工作在可高達(dá)20MHz的時(shí)鐘脈沖頻率下，所以對(duì)高速條件下的尺寸測(cè)量和動(dòng)態(tài)分析特別適合。圖2 TCD1209D及它的時(shí)序線陣CCD TCD1209D，以及它的時(shí)序圖如圖2所示。B.CCD和ARM處理器之間的傳輸速度為了提高CCD的數(shù)據(jù)采集速度，減少轉(zhuǎn)換時(shí)間，現(xiàn)使用高速A/D轉(zhuǎn)換器，以使它在高速環(huán)境下與ARM處理器進(jìn)行數(shù)據(jù)交換。這里選擇ADC08200，Analog公司