A New Design of the Vehicle Detection System for Measuring Outline Size

Transcription

1 3rd Internatonal Conference on Mechatroncs and Industral Informatcs (ICMII 205) A New Desgn of the Vehcle Detecton System for Measurng Outlne Sze Zhou Xao-bo,a*,Zhu Yong,b,Zhu Janhu2,c School of Physcs and Electronc Engneerng, Fuyang Teachers college,fuyang Anhu ,Chna 2 School of Mechancal Engneerng, Nanjng Unversty of Scence and Technology, Nanjng 20094, Chna a ahhfxaobo@sna.com, bzywdxy@qq.com,ffxyz505@gmal.com Keywords: dmenson parameters, sensor; laser screen, upper-computer; vehcle, controller Abstract. Vehcle dmensons parameters s an mportant part of vehcle traffcablty parameters and vehcle operaton safety testng. In order to measure the dmenson parameters accurately, a new vehcle dmensons detecton system whch based on laser screen, ultrasonc sensor, and upper-computer control software s desgned. It desgns and debugs the system's hardware and software, and sets up test lne, and the developed system s verfed. Expermental results show that the system can detect the dfferent models of vehcle dmensons wth hgh accuracy, non-contact, automated testng, have the characterstc of stablzaton, credblty, and error of calculaton s lower than %.It solves the problem of hgh ntensty of labor, neffcency, and human error, whch caused by Chna's vehcle testng nsttuton to test vehcle outlne dmenson manually. Introducton In recent years, vehcle overload has been one of the reasons for road traffc accdent, whch shortens the lfe span of road and brdge and affects natonal property and human lfe securty severely [-5]. Road Vehcle Dmenson, Axle Load and Qualty Lmt (GB589O2004), state mandatory standard, amng to govern oversze and overload from source has been come nto effect on Oct., 204[6-8];Vehcle structure cannot be transformed arbtrarly n the test tem of the overall vehcle of Operaton Vehcle Comprehensve Property Requrement And Test Method (GB8565O200) on Jun., 2009, t rases new requrement of some techncal parameters lke dmenson of motor vehcle and requres checkng and examnng dmenson of motor vehcle strctly[9,0]. At present, the measurement of vehcle dmenson by our country testng organzaton manly use steel tape, angle ruler and maker post for manual measurement, the vehcle must reman stable wth great labor ntensty, low effcency and bg personal error, whch cannot adapt to automatc detecton or complete non-contact automatc measurement[]. Therefore, studyng vehcle dmenson parameter non-contact quck test system, achevng correct measurement of dmenson parameter of vehcle and provdng an advanced vehcle dmenson test method wll have sgnfcance on governng oversze and overload from source so as to mprove traffc safety. Measurng prncple Dmenson of vehcle ncludes length, wdth and heght. Te optoelectronc scannng technque wth ultrasonc rangng technque and actual test task by usng dstrbutve control technology and advanced sensor. Combned wth crafty mechancal structure, control workng state of photoelectrc sensor and ultrasonc sensor and collectng sgnal of sensor through snglechp to realze automatc, rapd, hgh precse and non-contact measurement of automoble dmenson. Stereo structure of system s shown n the Fg., T-T8 n the Fgure s 8 pars of laser screen, used for measure length of vehcle; nstall 6 ultrasonc dstance measurng sensors on both sdes of portal frame for measurng wdth of vehcle; nstall 3 ultrasonc dstance measurng sensors on top of portal frame, used for measurng heght of vehcle. The vehcle sze range of devce measurng s 2.2m<length<4.2m 205. The authors - Publshed by Atlants Press 555

2 (length of vehcle s bascally larger than 2.2m), wdth <5m, heght <5m, and measurement of larger sze of vehcle can be expanded on ths bass. Fg. A perspectve dagram of the system Measurng prncple of length.length measurement manly uses laser correlaton lght curtan. As s shown n the Fg., T T8 s 8 pars of laser lght screen, the space between adjacent lght screens for the former 2 pars T T2 s l =20mm, the space between adjacent lght screens for T3 T 8 s l 2 =2000mm. Fgure 2 s the vertcal vew of 4 key states of measurng vehcle length by usng laser lght screen, the dotted arrow s laser projected by laser lght curtan, the shadow s vehcle for testng. We can see from the state n Fgure 2, The length of the vehcle to be measured. The value of the ntal value s determned by the state 3 and state 2 n Fgure. Fg. 2 Top vew of key states for Length measurng When vehcle to be tested drves nto measurement area from entrance, when there s no obstacle among correlaton lght curtan, lght curtan output sgnal N (=,2, 8)s at hgh level, otherwse the output sgnal N (=,2, 8) s at low level, the measurement calculaton method s as follows: () When vehcle to be tested enters length measurement area exactly, that s tal of vehcle has entered just n tme, as s shown n state of Fgure 2, calculate algebrac sum of output sgnal by 556

3 laser lght curtant 3 T 8, l vehcle. 8 = N, that s to calculate how many pars of lght curtan s blocked by = 3 (2) When vehcle to be tested blocks new laser lght curtan of T3 T8, that s 8 = 3 N = l, as s shown n state 2 of Fg. 2, start tmng devce, calculate algebrac sum of output sgnal by laser lght curtan T T2, l 2 2 = N.that s how many pars of lght curtan are blocked by vehcle. Because the = fxed space of laser lght curtan T3 T8 s 2000mm, and the fxed space of laser lght curtan T T2 s 200mm, the length ntal value of vehcle to be tested L 0 = (( 7 l) ( l2) 200) mm. (3) Snce we have measured ntal value of vehcle to be tested L 0, as long as we confrm the value of L, we can calculate the length of vehcle to be tested, the value of L s determned through state 3 and state 4 n Fgure 2. Measurng prncple s that 200mm short dstance wll be seemed as constant moton of vehcle. When vehcle contnues drvng the dstance of L as far as the new lght curtan released n T T2, that s 2 = N = l +, as s shown n state 3 of Fg. 2. Set the tme of readng tmng devce as t, at the same tme, restart tmng devce agan, thus t s the wastng tme of runnng L by vehcle. (4) When vehcle contnues to drve 200mm, release new lght curtan of T T2 agan, that s 2 N = l2 + 2, as s shown n state 4 of Fg. 2, set the tme of readng tmng devce as t2 = 2, thus t2 s runnng tme of 200mm by vehcle. For t s wthn 200mm of short dstance, t can be seemed as constant drvng, so L (200/ t2 t) mm. (5) Thus, length measured value of vehcle to be tested L= ( L0 + Lmm ). Measurng prncple of wdth and heght. As s shown n Fg., 6 ultrasonc sensors on both sdes of portal frame are nstaller. Of them, WL WL6 are on left sde and WR WR6 are on rght sde, used for measurng wdth of vehcles; three ultrasonc sensors nstalled on the top of portal frame H H3 s used for measurng heght of vehcle. Snce projecton of ultrasonc sensor has certan angle, proper dstrbuton of ultrasonc sensor can block wdth and heght of the overall vehcle to be tested. The wdth of portal frame s 5000mm and the heght s 5000mm. When vehcle to be tested passes by portal frame, ultrasonc sensor wll scan wdth and heght of vehcle. 6 ultrasonc sensors on left sde of portal frame wll compare data measured after many tmes and get a mnmum value WLmn, and the same for the rght sde for WRmn. Then, wdth of vehcle to be tested sw = (5000 WLmn WRmn ) mm. 3 ultrasonc sensor at the drecton of heght wll compare multple groups of data and get a mnmum valuew = (5000 WLmn WRmn ) mm, thus the heght of vehcle to be test s H = (5000 H ) mm. Structure of measurng system mn The system s manly made up of laser curtan, ultrasonc sensor, LED dsplay screen, length controller, wdth and heght controller, voce controller and upper computer, etc. usng RS485 bus for communcaton. Length, wdth and heght controller all use STM32F03 as controller. 8 sgnal processng crcuts are set n length controller, whch transform theoutput sgnal of laser lght curtan nto bnary sgnal to be dentfed by snglechp, used for judgng whether there s obstacle among correlaton lght curtans. Wdth and heght control panel ncludes 5 ultrasonc sensor drve crcuts, the measurement precseness of ultrasonc sensor reaches mm, blndng area s 20mm, and has temperature compensaton functon, the detectve dstance s 20mm-6000mm. voce controller s 557

4 made up of segment type voce chp, there are 82 segments of voce message stored n the voce chp (ncludng 0-9, A-Z, short name of each provnce, etc.). Accordng to the command of upper computer, LED dsplay curtan controllng 92*64pont wll dsplay the hnt nformaton of measurement and result. Composton structure of measurement system s as shown n Fg. 3. Software desgn of measurng system Fg. 3 Block dagram of the system Upper computer s wrtten by Vsual C++ software, coordnate and control the work of lower computer. When lower computer receves the command of startng sent from upper computer, t wll be n measurng state. After measurng, t wll send the data to upper computer. Upper computer wll compare the measured data wth standard data n database, and then send the measurement result and related nformaton whether t s qualfed to dsplay screen for dsplay and voce controller for report. When wdth controller receves the command of startng, t wll start ultrasonc sensor. If the measured dstance of heght ultrasonc sensor s bgger than 5m, t ndcates the vehcle enters wdth and heght measurement area, start wdth and heght measurement program to measure wdth and heght. Ultrasonc sensor wll scan the movng vehcle at the drecton of wdth and heght, and compare each measured result wth the prevous one and save the mnmum value H mn at last; nstall 6 sensors on both sdes at the drecton of wdth. Compare sx measured values of each sdes and get a mnmum value, compare t wth the prevous mnmum value and save the mnmum W Lmn and W Rmn. If remeasured value of heght ultrasonc sensor s the dstance from ground, t ndcates the end of wdth and heght measurement, calculate measured result and send t to upper computer, wdth W = 5000 W W mm, heght H = 5000 H ) mm. ( L mn R mn ) ( mn 558

5 Fg. 4 Flowchart of program for upper-computer Fg.5 Flowchart of program for measurng wdth and heght Fg.6 Flowchart of program for measurng length After length controller receves the command of startng, t wll start the functon of length measurement. When T lght curtan s blocked, t ndcates vehcle has entered measurement area, when T s released, n ndcates tal of vehcle has entered, that s, vehcle has entered length measurement area completely, record lght curtan state at that tme (whch lght curtans are blocked by vehcle). When the movng vehcle blocks new lght curtan, start tmer, calculate length ntal value L 0, accordng to the state of lght curtan and space of lght curtans. When there are lght curtans released, close tmer, calculate tmng tme Δt, and start tmer agan. When there are lght curtan released agan, close tmer, calculate tmng tme Δt2, then L (200/ t2) tmm, vehcle 559

6 length L= ( L0 + Lmm ), send length to upper computer and measurement s over. system software dagram s shown n the Fg.4, Fg.5 and Fg.6. Measurng test In order to verfy the measurement precseness of system aganst dfferent types of vehcle and stablty of system, test devce s nstalled n local vehcle testng organzaton, whch guarantees the need of test for all knds of vehcles. Test platform s as shown n Fg.7. because t s at test stage, use plastc flm to cover key areas for waterproofng. There wll be nevtably mechancal error durng devce nstallaton. It wll be corrected by measurng dstance of lght curtans, heght and wdth of portal frame and software. Test chooses three dfferent types of automoble, small car, mddle-sze car and large car. Each car s tested for three tmes contnuously, the speed s controlled wthn 0Km/h, and measured data s as shown n Table. It calculates comparatve error and standard error of measured data of each vehcle type, and verfes measurement precseness and stablty of system. We can see from the measured data, the bgger the vehcle dmenson s, the smaller the comparatve error s; we can see from standard error, the dscreteness and volatlty of measured data s small, and the stablty s good. Error analyss of length measurement: mechancal error of length measurement has been corrected by software. From measurement prncple, length measurement error manly focus on the measurement of L, L (200/ t2) t 200mm, only when t = or t 2 =, that s when vehcle s n state 2 or state 3 of stop for a long tme as s shown n the pcture, the measured error s bg, the maxmum of absolute error s 200mm. As long as vehcle drves normally, the error s small, for t can be seen as constant drvng wthn short dstance. Wdth and heght measurement error analyss: the precseness of ultrasonc sensor s mm, spreadng speed of ultrasonc s V c, the speed of vehcle to be tested s V car, wdth of vehcle to be tested s W, heght s H, and the scannng space of ultrasonc sensor at the drecton of wdth W = ((5 W)/2Vc 2 V car ) m, the scannng space of ultrasonc sensor at the drecton of heght H = ((5 H)/ Vc 2 Vcar ) m, spreadng speed of ultrasonc V c =340m/s, the small the dmenson of wdth and heght of vehcle, the farer from ultrasonc sensor, and the bgger the scannng space s. Suppose the mnmum wdth dmenson of vehcle s 2m, the mnmum heght dmenson of vehcle s.5m, speed of vehcle to be tested doesn t exceed 0km/h, that s V car =2.78m/s, thus W =0. 024m, H =0. 057m. Measure data for one tme at wdth drecton when maxmum space s 0.024m, Measure data for one tme at heght drecton when maxmum space s 0.057m. Ths s the man reason for wdth error and heght error. Reducng speed properly can ncrease precseness of measurement. Fg. 7 Expermental platforms 560

7 Table Measurement data of overall dmensons for the vehcle detecton system Vehcle model VW POLO JAC Sunray Tahu bus demenson Standard value (mm) Measured result (3 tmes mm) Comparatve error (%) Standard devaton Length Wdth Heght Length Wdth Heght Length Wdth Heght Conclusons Vehcle dmenson testng system realzes non-contact automatc measurement, overcomes a lot of problems of great labor ntensty, low effcency, personal error caused by usng steel tape, angle rule and marker post to test vehcle dmensons n our country vehcle testng organzaton. Through measurng test of varous vehcles, we can see from the testng data that, ths system s of hgh precseness, stablty and relablty and to the requrement of state. Acknowledgment Ths project s supported by the Scence and Technology Project of Anhu Provnce (50034), the Revtalzaton Plan Project of Anhu Provnce(203zytz04). We would lke to thank the sponsors. References [] Xe Chunl, Sun Fengyng. Vehcle loadng length vehcle system research and development, Sensor and Mcrosystem. 3 (202) 26-32(n Chnese). [2] Ma Yukun, Wang Zhongya, Yang Guowe. Road flatness measurement system based on lnear structure-lght sensor, Chnese journal of sensors and actuators. 26 (203) (n Chnese). [3] Xe Xaodan. Road transport vehcle oversze and overload control measure analyss. Archtectural Engneerng. (202) 20-23(n Chnese). [4] Su Jan & Zha Nabn. Research on automoble dmenson machne vsual measurement system [J]. Road Traffc Scence and Technology. 24(2007) 45-49(n Chnese). [5] Cheng Yanxng, Du Yng. Bref analyss of vehcle dmenson dynamc automatc measurng devce applcaton. Technology & Development. 20 (203) 33-36(n Chnese). [6] L Lnghu, Automoble test technque development overvew.automotve technology. 4 (202) 79-8(n Chnese). 56

8 [7] Su Chuq, Huang Lbo & Le Fangfang. Applcaton of vsual test on vehcle sze measurement. Automotve Engneer. 0 (2009) 37-39(n Chnese). [8] Wang Xa & Zhang Huan. Quanttatve Research on road oversze transport envronmental cost. Chna and Foregn Road. 30 (200) (n Chnese). [9] Jang Zawen. Mechansm and decson on road oversze and overload transport governng. X an, Chang an Unversty, 200(n Chnese). [0] Hu Qang. Countermeasure Research on road oversze and overload transport governng. Tanjn, Tanjn Unversty, 200(n Chnese). [] Jang Qngchang. Research on automoble dmenson measurng machne [D]. Harbn, Harbn Insttute of Technology, 2007(n Chnese). 562