THIET KE THIET BI DOC LOI XE OTO THEO
C H U A N O B DII TRONG HE
T H 6 N GCHAN DOAN OTO TlT XA
Nguyin Vdn Tiim, Le Hdng Lan
Bd mdn Dieu khiin hgc, Khoa Diin-Diin tir, Truang Dgi hgc GTVT Tdm tdt:
Bdi bdo dua ra md hinh he thong chdn dodn d td tir xa vd tap trung vdo thilt kl mdt chi tilt mdt phdn cua thilt bj tren xe, dd la thilt bj dgc md loi theo chudn OBD II. Thii nghiem thiet bj vd ddnh gid ket qud d^t dugc.
Tir khod: OBD II - On-Board-Diagnostic System Abstract:
This paper proposes a remote vehicle diagnostics system model and focus on a detailed design of the device on a vehicle, that's error code reader OBD II standard. Test equipment and evaluate the results achieved.
I. Gidl THI£U M 6 H I N H H ? T H 6 N G CHAN D O A N 6 T 6 Tir XA
Hinh 1 Id he thdng chdn . . - ^ „ ^ ^ . ^ dodn d td tir xa, bao gdm 3 he -^^'^"^
chuyen gia: He chuyen gia I tren xe „„^*»,, cd chiic ndng chdn dodn nhanh, so "^"^
bg tren cdc ca sd thdng tin tir OBD va sd lieu ky thudt xe; Neu cd dau hieu sy cd nghiem trgng se bdo ve tmng tdm. He chuyen gia II tai tmng
tam cd chiic narig chdn dodn ciing Hinh L Hf thing chdn doan 6 to tir xa dya tren cdc ngudn thdng tin nhu he
chuyen gia I vd nhung sau ban, ky hon ve nguyen nhdn, miic do sy co dua ra chdn dodn giiip ngudi qudn ly, gidm sat ra quyet djnh cudi ciing de bdo cho Idi xe, ciiu hd hodc tram sua chua.
He chuyen gia III tai tram sua chira su dyng ngodi cdc ngudn thdng tin tren cdn them cdc thdng tin khdc tu cdc thiet bj do tai tram. Vi vay kit qud chdn dodn se chi'nh xdc vd toan dien hon.
Thdng minh hoa qua trinh chan doan dya tren sir dung mdt sd cdng cy cua ITnh vyc tri tue nhdn tao, dd Id he chuyen gia, logic md vd mang no ron.
He chuyen gia chdn dodn mdy cd tdc dyng: Cho phep thyc hien chdn dodn mdy khdng can sy CO mat cua chuyen gia; Thay the cho con ngudi cd tn thiic cao, tao dieu kien cho cdng viec chan dodn mang tfnh khdch quan, nhdt la khi chdn dodn he thdng phiic tap; Phdt huy uu diem cua mdy tfnh ve do Idn cdc thdng tin tri thiic ciing nhu tdc do xu ly so vdi con ngudi.
Thiet bj dgc ma Idi Idy thdng tin ve ma Idi tren xe de cung cdp dii lieu ben canh tri thiic chuyen gia cho chan dodn d td. Muc 2 trinh chi tiet thiet ke chi tilt thilt bj dgc ma Idi.
n. THIET KE THIET BI DQCMA LOI XE 6 T 6 TOYOTA CAMRY 2.0 2.1. Cac giao thirc truyen thdng OBD 2
Cd 10 giao thiic:
+ SAEJI850PWM; +SAEJ1850VPW + ISO 9141-2; + ISO 9141-4 KWP (5 baud init, lO, 4 Kbaud);
+ ISO 9141-4 KWP (fast init, 10, 4 Kbaud); + ISO 15765-4 CAN (11 bit ID, 500 Kbaud);
+ ISO 15765-4 CAN (29 bit ID, 500 Kbaud); + ISO 15765-4 CAN (11 bit ID, 250 Kbaud);
+ ISO 15765-4 CAN (29 bit ID, 250 Kbaud); + SAE J1939 (NEW CAN)
2.2. Cac chudn chung ciia OBD II
Cau triic CLia phhn cirng OBD II la jack cai, 16 chan (2x8), chuan noi J1962. Vi trf Jack ndm d xung quanh khu vuc ghc ngudi lui, ben ghc phai hodc dudi vi trf tay lai [3-5J.
Cac tin hieu s u d u n g trong giao dicn ghep noi chudn OBD I I :
Hien nay cd 5 giao thirc tfn hieu sir dyng trong giao dien ghep ndi chudn OBD II [1].
+ SAE J1850 PWM (pulsc-widlh modulation -41.6 k-baud, chudn ciia cdng ty Ford Motor) + SAE J1850 VPW (variable pulse with -10.4/41.6 k-baud, chudn ciia General Motor)
+ ISO 9141-2 Id giao thirc cd t i c do du lieu 10,4 k-baud, vd tuong tu nhu RS-232. ISO 9141- 2
+ ISO 14230 KWP2000 (Keyword Protocol 2000)
+ ISO 15765 CAN (250 kbit/s hoac 500 kbit/s). Giao thirc CAN la mgt chudn phd biln ben canh cua cdng nghiep d td My va dugc sdn xudt theo chudn OBD II. Tir 2008, tdt cd cdc xe ban d My se yeu cau thyc hien CAN: pin 6: CAN high, pin 14: CAN low.
2.3. Thiet ke bg giai ma OBD II
Lya chgn chip chuyen dyng PIC24HJ64GP506; xir ly 16 bit, cd tdc do tfnh todn nhanh, chju dugc mdi tmdng rung xdc [6-7]. So do khoi ciia mach dien tren xe d td chuan OBD II nhu hinh 2.
Tir cdc ECU cua mdy tfnh tren xe, theo BUS CAN din bg tmyln dir lieu ra Jack OBD II tren xe, nhu hinh 2.
Hinh 2. So* do khoi mach dien tren xe o to So dd chdn ciia chudn OBD II nhu hinh 3
So do khdi ciia bd dgc ma Idi nhu hinh 4.
Bao gdm cdc khdi: khdi ghep ndi ngudn nudi;
khdi ghep ndi vdi Jack chudn OBD II de gidi md loi vd tmyen md loi len mdy tfnh thdng qua khdi ghep noi chudn USB hodc chudn RS-232.
Trong dd: Khdi cym CPU
Pin 2
1
Pin 7
1
naatDaoaa a a a a a a a a
p i m o Pin 10
Hinh 3. Jack tren xe theo chuan OBD II PIC24HJ64GP506: Bd vi xu- ly 16 bit. Giao tiep vdi CPU cua xe qua chudn CAN (baudrate:
500kbit/s). Xir ly thdng tin nhdn tir xe vd giri cdc thdng tin dd qua chudn RS-232; Khdi cum PL-2303: Bd chuyen ddi USB-UART. Tgo cong COM do tren mdy tinh de giao tiep vai chudn RS-232; Khdi cym SN65HVD1050: Bg truyen nhdn CAN. Truyen nhan tin hieu giira CPUvi Khdi ngudn nudi cho cdc IC: idy tnrc tiep tir xe hodc mdy dnh (USB) qua cdc IC dn dp 3.3V vd 5V. Khdi nap chuang trinh firmware.
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f Cai-baitery 6r (JSB": ^1-
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So do nli Jack OBD II vdi Dip 9 chan nhu hinh 5 Phan mim: Gdm 2 mo dun chuong trinh:
+ Chuong trinh cho chfp: Firmware dugc vilt va bien djch tren MPLAB IDE.
Nap chuong trinh xuong chip PIC24HJ64GP506: MPLAB ICD2.
PICkit2.
+ Chuang trinh tren mdy tfnh: viet tren c#.
2.4. Cac quy chuan bdt tay 2.4.1. Data format
+ Quy dinh tir T o o l ^ P C :
•jomssi
1 2 3 — 4 - 5 — 6 7 -....
8 9
5 (Signal Ground) - 4 (Chassis Ground) - 6 {CAN Hiflh (J-2284) - 7 ( I S O 9 1 4 1 - 2 K Lina) - 1 4 ( C A N Low J - 2 2 8 4 ) - 1 0 ( J 1 8 5 0 B U S - )
• 2 ( J i a S O B u s * ) - 1 5 ( I S O 9 1 4 1 - 2 L Lino)
• 1 6 (Banary Powor)
Hinh 5. So' do nli Jack OBD II voi Dip 9 chan
Header CmdYeu cau Datal Data2 DataN
Mdi data trong 1 khung Id 1 byte, cdc bit trong byte dugc sdp x§p theo chudn truyen nli tilp LSB ->MSB
Header : S6 Iirgng byte data se truyen (khdng tfnh Header byte vd Checksum byte). CmdYeu cdu: Command yeu cdu. Checksum = (<Header>+<SID>+<Datal>+<Data2>+...+ <DataN>) diing de ddm bdo ket thuc frame du lieu, vd thdng bdo du lieu da truyen diing.
+ Quy djnh tir Tool->PC:
upmm
Header Cmd Trd Idi Datal Data2
DataN emmm
Header: So Iirgng byte data se tmyen (khdng tfnh Header byte vd Checksum byte) Cmd Trd Idi: Command trd Idi.
Checksum = (<Header>+<SID>+<Datal>+<Data2>+...+ <DataN>) 2.4.2. Command yeu cau va tra Idi
Byte ndy Id sy thdng nhdt giiia software vd firmware, do ngudi lap trinh quy djnh.
Tool nhdn dugc yeu cdu tir PC, se bilt PC yeu cdu gi, vd cdn phdi Idy nhiing dii lieu ndo tir xe, sau dd sdp xep lai vd tmyen len PC de PC hien thi.
- May tinh yen cau kit not vdi Tool vd xe:
Cmd Yeu cdu = CMDJNIT = 0 (CMDJNIT la ky hieu dung trong code);
Cmd Trd Idi = CMDJNIT -\- 0x40 = 0x40.
- Mdy tfnh yeu cdu Idy DTC (Idi tir xe)
Cmd Yeu cdu = CMD_READ_DTC = 1 (CMD_READ_DTC Id ky hieu dung trong code) Cmd Trd Idi = CMD_READ_DTC + 0x40 = 0x41.
Mdy tinh yen can lay die lieu true tiep tirxe:
Cmd Yeu cdu = CMD.READ.LIVEDATA = 2 (CMD_READ_LIVEDATA Id ky hieu dung trong code). Cmd Trd Idi = CMD_READ_LIVEDATA + 0x40 = 0x42.
- Mdy tinh yeu cdu Idy dir lieu YIN cda xe (md xdc nhan xe):
Cmd Yeu cdu = CMD_REAb_VIN = 3 (CMD_READ_VIN Id ky hieu dung trong code);
Cmd Trd Idi = CMD_READ_VIN + 0x40 = 0x43
#define CMD_EslIT 0
#defme CMD_READ_DTC I
#define CMD_READ_LIVEDATA 2
#define CMD_READ_VIN 3 2.4.3. Communication format
May tinh yeu cau kk ndi v&i Tool vd xe: _ ,
Mdy tfnh giri lenh ndy xudng dl kilm tra xem Tool cd dugc ket ndi vao dung loai xe Camry 2.4L 2009 nhdp hay khdng? NIU dung thi cdc nut ReadDTC, LiveData, VIN tren software se dugc hien ra. NIU khdng thi software se thdng bdo yeu cdu kilm tra lai kit ndi.
+ PC gui xudng Tool:
0x01
+ Tool oiri tra Idi len PC: Tool giri frame tra Idi co 4 byte dir lieu (khdng tfnh Header va CS)
J2 , , "T Z—1—^ZTZ. I
0x04 10x40 I Datal | Dala2 Data3 | CS
Datal : thdng bao trang thai kcl noi cua tool va xc. (Datal = 0: ket noi dung xe , Datal != 0 : khdng kit ndi diing xe hoac khong nli tool vdi xe). Data2: Phien bdn thanh phdm cua firmware. Data3: Phien ban xay dung ciia firmware.
Mdy tinh yeu cau lay DTC (Idi tirxe) Read DTCs:
+ PC giri xudng Tool:
0x01 0x01 CS
+ Tool giri tra Idi len PC: c6 3 dang tra Idi Xe cd Idi:
OxXX I 0x41 I MIL DtclH DtclL Dtc2H Dtc2H C5
MIL: Trang thai ciia den bao loi (CHECK ENGINE LIGHT) tren xe.
MIL = 1: MIL ON : den bao loi sang; MIL = 0: MIL OFF: den bao loi tdt. DtclH: High bye of DTCl;
DtclL: Low bye of DTCl. DTC2H:
High bye of DTC2; DTC2L: Low byeofDTC2.
Chu y: chi dua toi da 16 loi ,vf dy:
ndi dung ciia cdc byte va ma Idi xem hinh 6.
DTCHigh (bytel) = 0x92;
DTCLow(byte2) = 0x34; DTC se Id : B1234.
Byla 1 Byie 2 J lb? M bi b4 b l \i bl bO b'"b« bS b. b l S bi tO
"Q
( H i « 0 F)11 • m«nufac>wr«r wiHiBl«< k« PTOCD m 11 • 8 A E ( M O T > « d l B m « » « e r 3 * n
( H M B ^ M M N I 0 ^-F)
OO • iSOSAf urtnlatf 0 1 - m v u b d i
»10 > I804AC cortralvd - 1 1 • tSOrtAC wnitv»»6
0 0 - 1 0 1 * « Osplay character 3 m used to Ueniify a tpcaic v«hiae
area Withm any araa. ^ p b y c^aractara 4 and 5 alow up lo 256 code definittona
Hinh 6. Noi dung cac byte va giai ma loi
$ 9
1 0
B
0 1
1
$ 2
0 0 1 1 | o
2
1^
$ 3
0 | o 1 1 1 1
3
$ 4
0 1 | o | o
4
Xe khdng cd Idi:
0x02 0x41^ MIL BB
Mdt kit ndi vdi xe: dung OxFE di phdn biet byte ndy do firmwere quy dinh
0x02 0x41 OxFE GS
Mdy tinh yeu cdu lay dir li^u true tiip tirxe Read Live Data:
+ PC giri xudng Tool:
0x01 0x02
+ Tool giri trd Idi len PC: cd 2 dang trd Idi Kit ndi diing xe (Camry 2.4L 2009 nhdp khdu )
OxOA 0x42 LDlSt LDIH LDIL LD2St LD2H LDIL LD3St LD3H LD3L
LDlSt, LD2St, LD3St: do firmwere qui djnh
LDIH : High bye of Engine RPM; LDIL: Low bye of Engine RPM.
LD2H : High bye of Vehicle Speed; LD2L: Low bye of Vehicle Speed.
LD3H : High bye of Time Since Engine Start; LD3L: Low bye of Time Since Engine Start.
De ra dugc gia trj thyc te, ta cdn phdi nhdn data nhdn dugc vdi I he sd ty le dugc quy djnh:
Engine RPM: he sd ty le: 0.25; Vehicle Speed : he sd ty le: 1.
Thdi gian tir luc bdt ddu khdi ddng xe (gidy): Time Since Engine Start: he sd ty le: 1.
Mdi thdng sd cdn 2 byte de xdc djnh gid trj
Vfdy : gid trj trd vl tir tool: LD 1 Hi =0x12; LDlLow = 0x78.
Engine RPM se hiln thi 0x1278 ^= scale(0.25) = 1182 rpm Mdt kit ndi vdi .\e
0x02 0x42 0x02 CS
- Mdy tinh yeu cdu lay dulieu VIN ciia xe (md xdc nhdn xe) Read Vehicle Information:
+ May tfnh yeu cau Tool:
0x01 0x03 CS
+ Tool giri trd Idi len PC: cd 2 dang
Ket noi dung xe (Camry 2.4L2009 nhdp khau,....)
0x12 0x43 Datal Data2 ... Data 16 Data 17 CS Datal-Datal7: 17 ASCII characters of VIN
Xe khdng ho trg dgc VIN qua ECU hodc khdng ket noi vdi xe 0x02 0x43 Data 0x46
Data = 0 : xe khong ho tig dgc VIN qua ECU; Data = 1: khong ket ndi vdi xe III. KET QUA THU NGHIEM THIET B| DOC MA LOI OBD II
Giao dien ket noi tren PC
Giao dien tren may tfnh nhu hinh 7, bao gdm cdc chirc nang:
Dgc ma loi: Read DTC; Kilm tra kit nli Tool Link; Sl lieu xe Live Data; Thong tin xe Vehicle Inf va thoat khoi chuang trinh Exit.
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I«^Lr* 1 Mil ijfl r fle*dDTc 1 p:i4r
UveOtfs V<*vJe \rla
1 - 1
Hinh 7. Giao dicn ket noi voi xe qua OBD Hinh 8. Thu nghiem xe Camry 2.0 LE Tra ciiu [2] www.canobd2.com. Ma P0306 - Xilanh 6 danh lira sai.
1 Toyota V P0306
D M a M i M
Hinh 9. Tra ciiai loi xe voi ma loi P0306
Thir nghiem tren xe Camry 2.0 LE, tai Cdng ty Toyota Gidi Phdng hinh 8 phat hien 2 Idi:
+ ip0102: Mass Air Flow Circuit Malfunction;
+ P0113: Intake Air Temperature (IAT) Circuit High Input.
Dgc dugc thdng sd ctia xe Camry 2.0 LE Id: VIN#JTNBE46K473088632.
IV.KETLUAN
Bdi bdo dua ra thilt kl thilt bj dgc ma Idi d to Toyota theo chudn OBD 2, ket qua thu nghiem tai tram bdo dudng Toyota Gidi phdng cho thdy thiet bj boat ddng tdt.
TAI LIEU THAM KHAO
[1]. VAD Pro-901 OBD-11 Universal Standards, Versatile Automotive Diagnostics, a division of HPA Motorsport Inc.
[2]. www.canobd2.com
[3]. In-Vehicle Networking, lecture 4 Introduction to SAE J1850 BAE 5030-003 Fall 2008, Instructor: Marvin Stone Biosystems and Agricultural Engineering Oklahoma State University.
[4]. Innovate Motorspoits, OT-1 16 Channel OBD-II Interface User Manual.
[5]. www.szhtech.com. SI-Reset BMW 0BD2.
[6]. BR16F84-1.07. OBD II Interface Chip Data Sheet For PWM, VPW. and ISO 9141-2 Vehicle. VPW (general motors), PWM (Ford products), and ISO 9141-2 (Asian/European), Jul 8 2001.
[7]. PIC24HJXXXGPX06/X08/X10 Data Sheet, High-Performace, 16-Bit Microcontrollers, 2007 Microchip Technology Inc.