United States Patent £191
`Bowler et al.
`
`[54] TIRE MONITORING APPARATUS Al'li'D
`METHOD
`
`[56]
`
`[75]
`
`Inventors: Paul R. Bowler, Surrey, Canada;
`John Mackay, South Durham,
`England; Shawn D. Lammers, Delta;
`Robert H. Fulton, North Delta, both
`of Canada
`[73] Assignee: TIC/Truck Tech Corp., Richmond,
`Canada
`[21] Appl. No.: 658,025
`[22] Filed:
`Feb. 21, 1991
`Int. a.s .............................................. B60C 23!02
`[51]
`[52] U.S. Cl •.................................... 73/146.5; 340/445
`(58] Field of Search ............................ 73/146.5, 146.8;
`375/143; 116/34R;340/442,445,447,858,859
`References Cited
`U.S. PATENT DOCUMENTS
`3,261,001 7/1966 Magnin ............................ 340/172.5
`3,309,463 3/1967 Roedl ................................. 178/69.5
`3.329,934 7/1967 Wooden ................................ 340/58
`3,810.090 5/1974 Davis. Jr. et al. .................... 340/58
`4,057,783 11/1977 Blanchier .............................. 340/58
`4,067,235 1/1978 Markland et al. ................. 73/146.5
`4,074,227 2/1978 Kalmus ................................. 340/58
`4.101.872 7/1978 Pappas ................................ 340/539
`4.119.944 10/1978 Smith .................................... 340/58
`4,137,520 1/1979 Deveau ................................. 340/58
`4,160,234 7/1979 Karbo et al. .......................... 340/58
`4.186.377 1/1980 Barabino ............................ 73/146.5
`4,237,728 12/1980 Betts et al. ......................... 73/146.5
`4,263,579 4/1981 Corgan et al. ........................ 340/58
`4.300.118 11/1981 Matsuda et al. ...................... 340/58
`4,328.494 5/1982 Goodall .......................... 340/870.18
`4,467,641 8/1984 Abraham ............................ 73/146.5
`4,510,484 4/1985 Snyder ................................ :. 340/58
`4,531.112 7/1985 Thomas ................................. 340/58
`4.571.588 2/1986 Lee et al. ....................... 340/870.13
`4,619,137 10/1986 Bott .................................... 73/146.5
`4,695.823 9/1987 Vernon ................................. 340/58
`4.703,650 11/1987 Dosjoub et al. ................... 73/146.5
`
`111111111111111111111111111111111111111111111111111111111111111111111111111
`US005231872A
`[11] Patent Number:
`[45] Date of Patent:
`
`5,231,872
`Aug. 3, 1993
`
`4,717,905 1/1988 Morrison, Jr. et al. .............. 340/58
`4,723,445 2/1988 Ripley et al. ....................... 73/146.3
`4,742,857 S/1988 Gandhi ................................ 152/418
`4,747,761 4/1988 Dosjoub et al. ................... 73/146.5
`4,816,802 3/1989 Doerksen et al. ................... 340/447
`4,893,110 1/1990 Hebert ................................. 340/442
`4,909,074 3/1990 Gerresheirn et al. .............. 73/146.4
`4,929,851 5/1990 Pace .................................... 307/359
`4,935,738 6/1990 Pilato ................................. 73/146.5
`4,975,679 12/1990 Ballyns ................................ 340/442
`5,001,457 3/1991 Wang et al .......................... 340/447
`5,040,562 8/1991 Achterholt ......................... 73/146.5
`5,054,315 10/1991 Dosjoub ............................. 73/146.5
`
`FOREIGN PATENT DOCUMENTS
`0251355
`l/1988 European Pat. Off ..
`0344003 11/1989 European Pat. Off ..
`0431217 6/1991 European Pat. Off ..
`3703128 2/1987 Fed. Rep. of Germany.
`2225300 11/1974 France .
`2601533 1/1988 France .
`2210537 6/1989 United Kingdom .
`
`Primary Examiner-Donald 0. Woodie!
`Attorney, Agent, or Firm-Bull, Housser & Tupper
`
`[57]
`ABSTRACT
`A method and apparatus for measuring a physical quan(cid:173)
`tity, property or condition and for transmitting a code
`representing the measured physical quantity, property
`or condition. The method includes the steps of develop(cid:173)
`ing a first signal in response to a physical quantity, prop(cid:173)
`erty or condition, sampling the first signal to produce an
`instantaneous first signal value, assigning a first code to
`the instantaneous first signal value, and transmitting the
`first code for reception by a receiver. The method and
`apparatus are explained in connection with a vehicle
`tire monitoring apparatus wherein plurality of tire units
`measure tire pressures and temperatures and transmit
`values representing pressure and temperature to a cen(cid:173)
`tral receiver located in a cab portion of the vehicle.
`
`52 Oaims, 46 Drawing Sheets
`
`COMPARATORS
`
`v+
`
`114
`
`TO TX GROUND
`
`12
`
`

`

`US. Patent
`
`Aug. 3, 1993
`
`Sheet 1 of 46
`
`5,231,872
`
`
`
`FIGURE I
`
`Page 000002
`
`

`

`US. Patent
`
`Aug. 3, 1993
`
`Sheet 2 of 46
`
`5,231,872
`
`
`
`FIGURE 2
`
`Page 000003
`
`

`

`US. Patent
`
`Aug. 3, 1993
`
`Sheet 3 of 46
`
`5,231,872
`
`\
`
`
`
`‘m’l‘
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`llzppppnapnpantnpn
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`
`
`il!l|l
`
`
`
`FlGURE 3
`
`Page 000004
`
`

`

`US. Patent
`
`Aug. 3, 1993
`
`Sheet 4 of 46
`
`5,231,872
`
`mv
`
`Va gnu...Gmmm“.
`..mts.fimmulllll
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`Page 000005
`
`

`

`US. Patent
`
`Aug. 3, 1993
`
`Sheet 5 of 46
`
`5,231,872
`
`:3“
`
`o\H
`
`4.58..“
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`gm
`
`Page 000006
`
`
`
`
`
`
`

`

`US. Patent
`
`Aug. 3, 1993
`
`Sheet 6 of 46
`
`5,231,872
`
`200
`
`202 / INTERNAL TIMER TIMEOUT AND
`
`
`INTERRUPT (WAKE UP) THE
`MICROPROCESSOR TO ENTER THE ACTIVE
`
`
`
`MODE (WAKE UP EVERY 25 SECONDS)
`
`
`
`
`INCREMENT FIRST INTERRUPT COUNTER 203
`INCREMENT SECOND INTERRUPT
`
`IS FAST
`
`'
`
`213
`
`
`
`
`Is SECOND mmm
`COUNT > SECOND
`INTERRUPT LIMIT
`
`DBCREMENT FAST Tx-COUNT
`
`(
`> 10 MINUTES )
`
`
`BFRSTWTERRUPT
`COUNT >FIRST
`mm IMT
`
`
`
`( >15 T0 20 SECONDS 3
`
`PERFORM UNIT CONVERSION
`
`
`
`PERFORM SAMPLE SAVE
`ROUTINE
`
`RESET FIRST AND SECOND
`INTERRUFT COUNTERS
`
`
`
`RETURN To Low
`P0 "ER MODE
`(SLEEP MODE)
`
`209
`
`PERFORM (TX)
`TRANSMIT ROUTINE
`
`FIGURE 6
`
`21°
`
`220
`
`212
`
`,
`
`Page 000007
`
`

`

`U.S. Patent
`
`Aug. 3, 1993
`
`Sheet 7 of 46
`
`5,231,872
`
`3f:/>
`
`4‘”
`
`
`
`4°2—
`
`4°3—
`
`
`4°7—
`
`
`fiGlHUE?
`
`Page000008
`
`

`

`U.S. Patent
`
`Aug. 3, 1993
`
`Sheet 8 of 46
`
`5,231,872
`
`Rc
`
`(RDATA)
`
`12 BITS
`
`TEMP REGISTER (TDATA)
`
`12 BITS
`
`PRESS REGISTER (PDATA)
`
`12 BITS
`
`BATI‘ REGISTER (VDATA)
`
`12 BITS
`
`REF REGISTER
`
`12 BITS
`
`Tc
`
`Pc
`
`Bc
`
`IKGCHUES
`
`Page 000009
`
`

`

`US. Patent
`
`‘
`
`Aug. 3, 1993
`
`Sheet 9 of 46
`
`5,231,872
`
`209
`316
`
`ENABLE
`POWER TO
`COMPARATORS
`
`DISABLE
`RAMP
`CIRCUIT
`
`DRAIN
`RAMP
`CAPACITOR
`
`SET
`PORT B
`T0 01H
`
`DEFINE
`PORT B AS
`
`INPUT PORT
`
`SET RDATA
`
`REGISTER
`TO 0
`
`START
`RAMP
`CIRCUIT
`
`318
`
`320
`
`322
`
`324
`
`26
`
`3
`
`323
`
`
`
`3
`
`IS
`
`B REGISTER
`=°
`
`338
`
`{0‘
`
`342
`
`IS
`PRESSURE
`BIT SET
`
`NO
`
`STORE RDATA 344 V
`VALUE IN
`PDATA REGISTER
`
`346
`
`CHANGE
`PRESSURE BIT TO
`
`
`
`INCREMENT
`RDATA VALUE
`TWICE
`
`348
`
`.
`
`o
`
`Is
`
`TEMPERATURE
`BIT SEI‘
`
`350 YES
`
`NO
`
`STORE RDATA 352
`VALUE IN
`TDATA REGISTER
`
`354
`
`CHANGE
`TEMPERATURE
`
`BIT T0 OUTPUT ANDSETTOO
`
`INCRBMENT
`RDATA VALUE
`TWICE
`
`.
`
`355
`
`a
`
`FIGURE 9A
`
`0
`
`Page 000010
`
`INCREMENT
`
`V RDATA
`' REGISTER
`
`
`
`330
`
`REGISTER
`
`

`

`US. Patent
`
`Aug. 3, 1993
`
`Sheet 10 of 46
`
`5,231,872
`
`360
`
`362
`
`STORE RDATA
`
`VALUE IN VDATA
`REGISTER
`
`
`
`CHANGE
`VOLTAGE BIT T0
`
`OUTPUT AND SET
`TO 0
`
`
`
`358
` IS
`VOLTAGE
`BIT SET
`
`NO
`
`IS
`REFERENCE
`BIT SET
`
`366
`YES
`
`‘ 369
`
`370
`
`372
`
`DISABLE
`
`CIRCUIT
`
`
` DISABLE
`POWER TO
`
`
`
`COMPARATORS
`
`
`
`374
`
`INCREMENT
`RDATA VALUE
`
`TWICE
`
`3‘54
`
`W
`
`INCREMENT
`RDATA VALUE
`TWICE
`
`
`
`358
`
`FIGURE 9B
`
`Page 000011
`
`

`

`US. Patent
`
`Aug.‘3, 1993
`
`Sheet 11 of 45
`
`5,231,872
`
`UNIT CONVERSION ROUTINE
`
`2K
`
`390
`
`CALCULATE AND STORE Tt
`Es
`Tt = (MT ch)TC + bf
`
`39?.
`
`CALCULATE AND STORE Pt
`
`
`
`
`
` Pt=a~ap1§§cwc+br
`
`39“
`CALCULATE AND STORE Bt
`
`Bx = (MB BR—Cm )BC + b3
`
`
`
`
`
`
`TO COMPARISON
`
`ROUTINE
`
`FIGURE 10
`
`Page 000012
`
`

`

`US. Patent
`
`Aug. 3, 1993
`
`Sheet 12 of 46
`
`5,231,872
`
`378
`
`380
`
`382
`
`384
`
`386
`
`388
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`FIGURE 11
`
`Page 000013
`
`

`

`US. Patent
`
`Aug. 3, 1993
`
`Sheet 13 of 46
`
`5,231,872
`
`IS
`IT! - Tl—l i
`’A TEMP LIMIT
`
`‘
`
`
`
`
`
`IS
`
`
`
`lP1 - PL; 1
`.
`’A PRESS LIMIT
`
`419
`
`
`
`
`
`SET FIRST
`SET FIRST
`
`INTERRUPT LIMIT
`INTERRUPT LIMIT
`
`= 1 FOR 2.5 SEC
`TO 1 FOR 2.5
`
`
`
`SAMPLING
`SEC. SAMPLING
`
`
`
`
`
`
`IS
`
`12—9>
`
`
`i?! ' P1-1|1At
`lTl ' TI'l I fAt
`
`>13 PIA t LIMIT
`
`> AT/A t LIMIT
`
`
`YES
`
`
`
`SET BIG PRESS
`CHANGE FLAG
`
`SET BIG TEMP
`CHANGE FLAG
`
`428
`
`SET FAST TX COUNT
`
`
`= 2 ( D0 3 TRANSMISIONS
`
`AT 2.5 SEC INTERVALS)
`
`
`
`4 4
`SET BATTERY
`
`YES CONDITION FLAG
`
`TO ACTIVE
`
`
`
`SET FIRST
`INTERRUPT LIMIT
`TO 8 OR MORE
`20 SEC OR MORE
`
`
`
`
`
`FIGURE 12
`
`425
`
`‘26
`
`Page 000014
`
`

`

`US. Patent
`
`Aug. 3, 1993
`
`Sheet 14 of 46
`
`5,231,872
`
`396
`
`398
`
`400
`
`TEMP AT TIME t—I
`
`TM
`
`8 BITS
`
`PRESS AT TIME t-l
`
`PM
`
`8 BITS
`
`8 BITS
`
`BATI‘ AT TIME t—l
`
`BH
`
`414
`
`BATTERY CONDITION
`
`1 BIT
`
`409
`
`411
`
`BIG PRESSURE CHANGE
`
`1 BIT
`
`BIG TEMPERATURE CHANGE 1 BIT
`
`FIGURE 13
`
`Page 000015
`
`

`

`US. Patent
`
`Aug.3, 1993
`
`7
`
`Sheet 15 01‘46
`
`5,231,872
`
`405
`
`406
`
`AP/A t LIMIT
`
`dP/dt
`
`ATIA t LIMIT
`
`dT/dt
`
`8 BITS
`
`8 BITS
`
`408
`
`410
`
`412
`
`FIGURE 14
`
`Page 000016
`
`

`

`US. Patent
`
`Aug. 3, 1993
`
`Sheet 16 of 46
`
`5,231,872
`
`210
`
`SAMPLE SAVE ROUTINE
`
`\
`
`
`
`
`
`
`
`
`
`SHIFT '1‘t TO '1;1
`
`
`
`SHIFT Pt TO PH
`
`
`
`
`TO TRANSMIT ROUTINE
`
`FIGURE 15
`
`428
`
`430
`
`
`
`
`
`432
`
`Page 000017
`
`

`

`US. Patent
`
`Aug. 3, 1993
`
`Sheet 17 of 46
`
`5,231,872
`
`376
`
`. -\N
`
`434
`
`436
`
`438
`
`440
`
`442
`
`UNIT FUNCTION
`
`UNIT ID ( LS BYTE )
`
`UNIT ID (MS BITS )
`
`TIRE NUMBER
`
`UNIT TYPE
`
`FFEURElfi
`
`Page 000018
`
`

`

`US. Patent
`
`Aug. 3, 1993
`
`Sheet 18 of 45
`
`5,231,872
`
`SEND 010
`RESYNCIIRONIZER
`
`SEND PRESSURE
`BYTE
`
`SEND 010
`RESYNCHRONIZER
`
`SEND TEMPERATURE
`BYTE
`
`' ‘
`
`4
`
`4'6
`
`4
`
`7!
`
`SEND 010
`RESYNCHRONIZER
`
`7
`4
`
`-
`
`SEND CRC
`B
`
`4
`
`7
`
`4
`
`7
`
`44
`
`44
`
`c
`
`45
`
`44
`
`4
`
`S
`
`4
`
`5
`
`4
`
`S
`
`212
`
`ENABLE TRANSMITTER
`
`SEND 8 ZEROS
`
`SEND 010
`RESYNCHRONIZER
`
`SEND UNIT
`
`FUNCTION BITS (5)
`
`SEND BIG PRESSURE
`CHANGE BIT
`
`SEND BIG TEMPERATURE
`CHANGE BIT
`
`SEND BATTERY
`CONDITION BIT
`
`SEND 010
`RESYNCI-IRONIZER
`
`SEND ID
`LS BYTE
`
`SEND 010
`RESYNCHRONIZER
`
`SEND SENSOR ID
`
`MS BITS (2)
`
`SEND UNIT TYPE
`BIT
`
`‘
`
`SEND TIRE
`NUMBER (5 BITS)
`
`4
`
`5
`
`‘
`
`DISABLE TRANSMITTER
`
`-w
`
`4
`
`5.
`
`4
`
`5‘
`
`«a
`
`46
`
`FIGURE 3.7
`
`Page 000019
`
`

`

`US. Patent
`
`Aug. 3, 1993
`
`Sheet 19 of 46
`
`5,231,872
`
`476
`
`
`
`lo 1 o]
`
`sans
`
`IBHBHBHO 1 0‘
`
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`
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`6192101019191.
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`TIRE NO.
`496’}
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`498'J
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`i
`
`8BITS
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`
`668
`
`670
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`
`BBITS
`TEMPERATUREBYTE
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`
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`CRC BYTE
`SOS—J
`
`‘
`
`FIGURE 18
`
`Page 000020
`
`

`

`U.S. Patent
`
`Aug. 3, 1993
`
`Sheet 20 of 46
`
`5,231,872
`
`mmHgo
`
`moammmzmu
`
`MmHgo
`
`zen—”HEADQOE
`
`FIGURE 19
`
`Page 000021
`
`
`
`

`

`US. Patent
`
`Aug. 3, 1993
`
`Sheet 21 of 46
`
`5,231,872
`
`Sm
`
`0%mgm8Em
`.8528E2g,$3893.922,328N8
`
`mofimmazHq
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`
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`
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`
`FNSURESZO
`
`Page 000022
`
`
`
`

`

`US. Patent
`
`Aug. 3, 1993
`
`Sheet 22 of 46
`
`5,231,872
`
`moa¢m4mzoo09
`
`vawaszH
`
`one 2mg
`
`
`98
`
`
`
`moaumama20mm
`
`mamsomabo
`
`FIGURE 21
`
`Page 000023
`
`
`
`

`

`US. Patent
`
`Aug. 3, 1993
`
`Sheet 23 of 46
`
`5,231,872
`
`96% w m
`
`ACCESSORY
`
`CHECKING
`
`
`ROUTINE
`
`802
`
`‘ ' '
`
`VALID
`CARRIER
`
`YES
`
`. n
`
`DATA
`
`RECEIVING
`
`806
`
`ROUTINE
`
`
`
` MICRO
`
`ACTIVATION
`
`ROUTINE
`
`
`
`UPLOAD
`ROUTINE
`
`‘
`
`808
`
`810
`
`SUBCONTROLLER
`
`MONITORING PROGRAM
`
`FIGURE 22
`
`Page 000024
`
`

`

`US. Patent
`
`Aug. 3, 1993
`
`Sheet 24 of 46
`
`5,231,872
`
`ACCFSSORY CHECKING
`ROUTINE
`
`ACCESSORY
`CHECK
`
`so:
`
`[—
`
`N0
`
`SECOND
`MICRO
`ON
`
`SECOND
`MICRO
`ON
`
`YES
`
`80
`
`NO
`
`IS ONIOFF
`KEY
`PRESSED
`
`SECOND
`
`
`
`MICRO ON
`
`
`
`
`MICRO ON
`
`0
`
`TURN
`SECOND ~
`
`PERMISSION
`TO SHUT
`OFF
`
`@839
`
`
` TURN
`SECOND
`
`MICRO OFF
`
`
`
`:35!
`@
`
`
`TO SECOND
`MICRO
`
`
`
`FIGURE 23
`
`Page 000025
`
`

`

`US. Patent
`
`Aug. 3, 1993
`
`Sheet 25 of 46
`
`5,231,872
`
`‘”\ a
`
`ZERO SEQUENCE
`DEFECTOR
`SUBROUTINE
`
`RESET ZERO
`COUNTER REGISTER
`
`
`
`
`INCREMENT
`ZERO COUNTER
`
`700
`
`702
`
`706
`
`REGISTER
`
`
`
`
`’n’ SUCCESSIVE
`ZEROS BEEN
`
`
`RECEIVED
`
`SAMPLE FIRST
`INPUT 634
`
`708
`
`IS
`
`lNPUT
`
`LEVEL
`
`HIGH
`
`FIGURE 24
`
`Page 000026
`
`

`

`US. Patent
`
`Aug. 3, 1993
`
`Sheet 26 of 46
`
`5,231,872
`
`712
`
`\ 010 SEQUENCE HANDLING ROUTINE
`
`
`
`714
`
`
`INITIALIZE
`SAMPLE REG
`LEVEL REG
`
`
`SEQUENCE REG
`
`
`
`
`
`
`
`
`INCREMENT
`SEQUENCE
`
`REGISTER DIVIDE
`
`715
`
`SAMPLE REG
`CONTENTS BY 2
` INCREMENT
`
`SAMPLE REG
`AND SAMPLE
`INPUT 634
`
`
` AND SAMPLE
`WITH STORED
`
`SAMPLE
`
`
`
`
` AND SAMPLE
`WITH STORED
`
`SAMPLE
`
`
`IS
`IS
`
`
`
`SAMPLE
`RESULT OF
`
`73
`
`VALUE = 0
`
`AND = 0
`
`$3
`
`FIGURE 25
`
`“‘53
`
`Page 000027
`
`

`

`US. Patent
`
`Aug. 3, 1993
`
`Sheet 27 of 46
`
`5,231,872
`
`/ 738
`
`DATA‘HANDLH‘IG ROUTINE
`
`a
`REGISTER
`
`INCREMENT
`SAMPLE
`
`74
`
`IS
`
`SAMPLE REG
`= 1.5 BIT TIME
`
`
`
`
`
`
`
`RESET 3mm 744
`REG T0 0
`RESET SAMPLE
`‘ STORAGE
`
`
`
`INCREMENT
`
`SAMPLE
`
`REGISTER
`
`
`
`
`
`IS SAMPLE
`REG = 30%
`
`BIT TIME
`
`
`
`
`
` IS SAMPLE
`IS SAMPLE
`REG = 50%
`
`BIT TIME
`
`
`
`
`
`IS SAMPLE
`REG = 70%
`
`BIT TIME
`
`
`
`FIGURE 26A
`
`Page 000028
`
`

`

`US. Patent
`
`Aug. 3, 1993
`
`Sheet 28 of 46
`
`5,231,872
`
`760
`
`a P
`
`LACE STORED
`
`
`
`SAMPLE IN BIT
`STORAGE REG
`
`
`
`
`
`@+
`
`
`
`HAVE ALL
`
`
`
`BITS IN DATA
`PACKET BEEN
`
`
`RECEIVED
`
`
`INCREMENT
`
`REGISTER
`
`BIT POSITION
`
`
`HAS FINAL 010
`SEQUENCE
`
`
`BEEN RECEIVED
`
`PERFORM
`
`ALGORITHM
`
`CALL
`
`UPLOAD
`
`ROUTINE
`
`FIGURE 26B
`
`Page 000029
`
`

`

`US. Patent
`
`Aug. 3, 1993
`
`Sheet 29 of 46
`
`5,231,872
`
`0123456 89101112
`
`
`74 _IIIIIIIIEIEIIIII
`
`
`'26
`
`vs
`
`
`
`
`FIGURE 27
`
`
`
`
`
`Page 000030
`
`

`

`US. Patent
`
`Aug. 3, 1993
`
`Sheet 30 of 46
`
`5,231,872
`
`'
`
`SECOND MICRO
`
`'
`
`ACTIVATION ROUTINE
`
` 784
`
`SECOND IMICRO
`
`ACTIVATION ROUTINE
`
`FIGURE 28
`
`Page 000031
`
`

`

`US. Patent
`
`Aug. 3, 1993
`
`Sheet 31 of 46
`
`5,231,872
`
`ACTIVATE
`
`INTERRUPT
`‘ LINE
`31d OUTPUT 642
`
`
`
`
`
`
`SETUP AND
`
`STORE DATA
`TO 2nd MICRO
`
`
`
`FIGURE 29
`
`Page 000032
`
`

`

`US. Patent
`
`Aug. 3, 1993
`
`Sheet 32 of 46
`
`5,231,872
`
`5.5D
`
`3%EmaD
`
`Page 000033
`
`

`

`US. Patent
`
`Aug. 3, 1993
`
`Sheet 33 of 46
`
`5,231,872
`
`MAIN LOOP
`
`Z//// 808
`
`810 812
`
`814
`
`EHGEWEEBI
`
`Page 000034
`
`

`

`US. Patent
`
`Aug. 3, 1993
`
`Sheet 34 of 46
`
`5,231,872
`
`USEDMAP'
`
`§
`
`’ 839
`
`/
`
`841
`
`AXLE MAP
`
`UNITCODES
`
`DISPLAY
`
`
`
`
`
`
`
`864i
`l0
`TABLE
`
`
`AUX_P
`40
`
`
`
`40
`
`4:;C)
`
`J).
`
`MAIN P
`TABLE
`- DELTA__P
`
`NEW T
`
`AUX—T
`
`MAIN T
`
`
`
`862
`
`866
`
`868
`
`870
`
`FIGURE 32
`
`Page 000035
`
`

`

`US. Patent
`
`Aug. 3, 1993
`
`Sheet 3s'of 46
`
`5,231,872
`
`810
`
`816 /
`
`ENABLE
`
`ROWS
`
`81.
`N0
`
`IS
`AKEY
`PRESSED
`
`YES
`
`DETERMINE
`KEY
`
`820
`
`TERMINATE
`KEYBOARD
`CHECK
`
`82
`
`822/
`
`87'
`
`FIGURE 33
`
`Page 000036
`
`

`

`US. Patent
`
`Aug. 3, 1993
`
`Sheet 36 of 46
`
`5,231,872
`
`
`
`ADDRESS REGISTER
`TO ZERO
`
`SET CODE TABLE @
`
`94
`
`93
`
`o
`
`35
`
`9
`
`9
`
`36
`
`37
`
`9
`
`33
`
`9
`
`9
`
`39
`
`9
`
`40
`
`ANY ENTRIES
`
`1N DISPLAY
`
`YES
`
`PROIVIPT USER
`FOR ID
`
`WAIT FOR
`ENTRY OF ID
`
`UPDATE mm
`AND UNITCODES
`
`UPDATE
`USEDMAP
`
`‘
`
`SET LED’S
`TO GREEN
`
`927
`
`92g
`YES
`
`2
`9 I
`
`93°
`
`931
`
`WAIKE§OR
`
`WAS
`ENTER PRESSED
`NO
`
`WAS
`AXLE PRESSED
`YES
`
`GET USEDMAP
`ENRY
`
`WAS
`ENTRY ZERO
`
`YES
`
`
`
`CYCLE THROUGH 932
`
`
`SEQUENCE 1N
`DISPLAY TABLE
`
`
`
`LIGHT ARE IN
`
`
`ORANGE W.R.T.
`SEQUENCE
`
`
`
`933
`
`ERASE
`DISPLAY
`
`INCREMENT CODE
`TABLE ADDRESS REG
`
`9‘“
`
`FIGURE 34
`
`Page 000037
`
`

`

`US. Patent
`
`Aug. 3, 1993
`
`Sheet 37 of 45
`
`5,231,872
`
`
`
`USEDMAP UNIT AXLE #
`
`UNITCODES
`
`
`
`
`
`
`
`
`
`FIGURE 35
`
`Page 000038
`
`

`

`US. Patent
`
`Aug. 3, 1993
`
`Sheet 38 of 46
`
`5,231,872
`
`/_826
`
`CLEAR DISPLAY
`
`943
`
`ANY ENTRIES
`IN DISPLAY
`
`949
`
`N0
`
`LIGHT LED’S ON
`AXLE IN ORANGE
`
`
`
`COPY USEDMAP
`ENTRY T0 DISPLAY
`
`943
`
`FIGURE 36
`
`PROMPT USER
`FOR ’HI’ LIMIT
`
`GET VALUE
`
`GO THROUGH
`DISPLAY SET ALL
`RESP. TIRES
`T0 I-HGH HMIT
`
`PROMPT USER
`FOR ’LOW’ LIMIT
`
`
`
`
`
`
`
`
`
`
`GET VALUE
`
`
`GO THROUGH
`
`
`DISPLAY SET ALL
`
`RESP. TIRES
`TO HIGH LIMIT
`
`
`
`
`956
`
`Page 000039
`
`

`

`US. Patent
`
`Aug. 3, 1993
`
`Sheet 39 of 46
`
`5,231,872
`
`970
`
`DATA /
`
`ROUTINE
`
`TRAN SEER
`
`READ NEWPRESS
`AND AUXPRESS‘
`
`SEMAPHORE REG
`
`971
`
`IS
`
`NEWPRESS
`
`972
`
`= BUSY
`CALL REGISTER
`974
`
`
`CALL REGISTER
`TO TABLE COPY
`TO TABLE COPY
`
`
`
`ROUTINE
`ROUTINE
`
`
`DESTINATION
`DESTINATION
`
`
`
`IS NEW__P
`IS AUX_P
`
`SET
`
`
`SET
`
`
`AUXPRESS TO
`NEWPRESS T0 '
`
`WAITING
`WAITING
`
`
`
`975 .
`
`COPY
`
`TEMPERATURE BYTE
`
`975.1
`
`980
`
`FIGURE 37
`
`Page 000040
`
`

`

`US. Patent
`
`Aug. 3, 1993
`
`Sheet 40 of 46
`
`5,231,872
`
`982
`
`REGISTER-TO-TABLE COPY ROUTINE
`
`\
`
`REGISTER TO
`
`ROUTINE
`
`TABLE COPY
`
` 984
`
`
`
`CODE FROM SECOND
`
`READ UNIT ID
`
`CODE REGISTRER
`
`
`
`
`DETERMINE AXLEMAP
`SUB—TABIE STARTING
`
`ADDRESS
`
`986
`
`DETERMINE L
`(No.0FAXLEREIATIVE
`
`TOUNIT)
`
`988
`
`
`DETERMINE C
`
`
`(No. 117 DISPLAY AXLE
`CORRESPONDING TO
`
`
`THE UNIT AXLE
`
`
`
`DETERMINETABIE
`
`LOCATION
`
`4(C-L) + N =T
`
`COPY PRESSURE
`
`BYTE FROM SECOND
`
`PRESS’I'EMP REGISTER
`
`INTO LOCATION T
`
`FIGURE 38
`
`Page 000041
`
`

`

`US. Patent
`
`Aug. 3, 1993
`
`Sheet 41 of 46
`
`5,231,872
`
`812
`
`PRESSURE
`CHECKING ROUTiNE
`
`CALL TABLE
`
`COPY ROUTINE
`
`
`
`
`
`
`
`
`FIGURE 39
`
`Page 000042
`
`

`

`US. Patent
`
`Aug. 3, 1993
`
`Sheet 42 of 46
`
`5,231,872
`
`TABLE
`COPY ROUTINE
`
`'
`1/—
`
`974
`
`READ NEWPRESS
`
`AND AUXPRESS
`
`998
`
`SET NEWPRESS
`= BUSY
`
`SEMAPHORES YES
`
`
`
`COPY NEW P
`TO MAIN ’13
`
`SET NEWPRESS
`= NONEW
`
`1901
`
`1902
`
`1903
`
`AUXPRESS
`YES
`= WAITING
`
`
`SET AUXPRESS
`= BUSY
`
`“305
`
`COPY AUX__P
`T0 MAIN_P
`
`
`
`
`SET AUXPRESS
`= NONEW
`
`1906
`
`1007
`
`FIGURE 40
`
`Page 000043
`
`

`

`US. Patent
`
`Aug. 3, 1993
`
`Sheet 43 of 46 ’
`
`5,231,872
`
`/\ 976
`
`1012
`
`COMPARE ALL
`
`VALUES
`
`LOW P VALUES
`WTI‘H ELL MAIN__P
`
`
`
`1014
`
`
`
`MAIN_P VALUES YES
`
`
`
`
`
`COMPARE ALL
`
`HIGH} VALUES
`WITH ALL MAIN_P
`
`VALUES
`
`
`
`ANY
`MAIN_P VALUES YES
`
`GREATER THAN
`
`HIGH_P
`
`
`
`COMPARE ALL
`
`DELTA_P VALUES
`WITH ALL MAIN_P
`
`VALUES
`
`GREATER THAN
`
`
`
`HIGH_P
`
`FIGURE 41A
`
`Page 000044
`
`

`

`US. Patent
`
`Aug. 3, 1993
`
`Sheet 44 of 46
`
`5,231,872
`
`97?
`
`READ BATTERY 102‘
`CONDITION BIT
`
`
`'SET BA’IT
`
`$ YES INDICATOR T0
`
`
`RED
`
`DETERMINE TABLE
`
`TO RED
`
`LOCATION(S) AND SET
`
`1030
`
`1028
`
`SOUND ALARM
`
`“’32
`
` 1036
`
`CALCULATE
`NEW DELTA_P
`
`
`TABLE VALUE
`
`1036
`
`RETURN
`
`FIGURE 41B
`
`Page 000045
`
`

`

`US. Patent
`
`Aug. 3, 1993
`
`Sheet 45 of 46
`
`5,231,872
`
`PRESSED
`
`NUMERIC VALUE
`OF AXLE KEY
`
`DETERMINE
`
`103 '
`
`1050
`
`1052
`
`1054
`
`LIGHT PREVIOUS
`LED IN GREEN
`
`AND NEXT LED IN
`
`GET USEDMAP
`
`ENTRY FOR
`
`
` GET USEDMAP
`THIS AXLE
`
`
`ENTRY FOR
`
`
`
`DETERMINE NEXT
`LED IN SEQUENCE
`
`FROM USED MAP
`TABLE
`
`
`
`
`
`ORANGE
`
`(OR TEMP) ON
`DISPLAY
`
`FIGURE 42
`
`Page 000046
`
`

`

`US. Patent
`
`Aug. 3, 1993
`
`Sheet 46 of 46
`
`5,231,872
`
`c
`
`2004 21%
`___.
`2010
`20:8
`
`2 0 [6
`
`)7;
`
`1
`
`
`
`
`?
`
`
`a
`I
`
`’
`
`
`FIGURE 43
`
`Page 000047
`
`

`

`1
`
`5,231,872
`
`TIRE MONITORING APPARATUS AND METHOD
`
`BACKGROUND OF THE INVENTION
`
`The invention relates to a method and apparatus for
`measuring a physical quantity, property or condition,
`transmitting a code representing the physical property,
`quantity or condition to a receiver and displaying a
`representation of the physical property, quantity or
`condition on a display at a central location. Such an
`apparatus and method has particular application in
`monitoring pressures and temperatures of air in tires,
`and displaying such air pressures and temperatures on a
`diSplay located in a cab portion of a vehicle on which
`the apparatus is installed.
`In pneumatic tired vehicles such as mining trucks,
`logging trucks, and semi~trailers etc, pneumatic tire
`problems can affect the operating cost of such vehicles.
`Operating costs are affected when a tire becomes flat
`due to wear or puncture as tires must often be replaced
`or repaired. This leads not only to a cost in effecting the
`repair but also leads to a cost due to temporary loss of
`use of the vehicle.
`Other problems associated with pneumatic tires in—
`clude road wear due to improperly inflated tires and
`loss of effectiveness of anti-lock braking systems result-
`ing from reduced friction due to over or under inflation
`of tires.
`Operating costs of vehicles can, however, be mini-
`mized and road wear and loss of effectiveness of anti-
`lock breaking systems can be reduced by careful main-
`tenance of tires. More specifically, it” tire pressures are
`monitored and maintained within predefined limits, tire
`wear and road wear can be reduced and the effective-
`ness of anti~lock braking systems can be maintained.
`Additionally, if the air temperature within a tire is moni-
`tored, excessive heating of the tire can be observed,
`serving as a warning that possible tire damage or blow-
`out is imminent.
`Previously, monitoring of tire pressures and tempera-
`tures was done by simply using a conventional
`tire
`gauge to measure tire pressure and by simply touching
`the tire to determine if it appeared excessively warm.
`While the use of the pressure gauge is reasonably accu-
`rate,
`it could only be used while the vehicle was
`stopped. Measuring temperature also had to be done
`while the vehicle was stopped and an operator could
`only guess that the tire may be too hot.
`What is required therefore is a method and apparatus
`for monitoring tire pressures and temperatures while
`the vehicle is in use.
`Certain inventors before us have sought to address
`the problem of measuring tire pressure. Por example the
`US. Pat. No. 4,237,728 to Betts et al discloses a low tire
`warning system which monitors tire inflation and sends
`a coded signal to a central receiver when the tire infla-
`tion is less than a predetermined value or threshold. It
`appears that actual tire pressure is not monitored, but
`instead a warning is generated when threshold is at-
`tained. Furthermore, there appears to be no mention of
`measurement of air temperature within the tire.
`US. Pat. No. 4,742,857 to Gandhi discloses a tire
`pressure sensor and air supply for maintaining a desired
`air pressure in a tire. The device monitors air pressure in
`a tire by creating movement of a reluctance-type of
`pressure sensing element which cooperates with a re-
`ceiving transducer mounted adjacent the tire. on the
`frame of the vehicle. While continuous measurement of
`
`10
`
`15
`
`20
`
`25
`
`3O
`
`35
`
`45
`
`50
`
`60
`
`65
`
`2
`tire pressure is possible, installation of a plurality of
`reluctance sensor elements and corresponding transduc-
`ers is required. Furthermore, the transducers must be
`placed in close proximity to the sensor elements on the
`tires resulting in little clearance between the sensor and
`transducer. This can leave the system susceptible to
`damage due to debris lifted from the road by a tire as
`could frequently occur if the device was used with a
`mining vehicle or logging truck. Furthermore, Gandhi
`does not appear to disclose simultaneous monitoring of
`air temperature within a tire.
`U.S. Pat. No. 4,067,235 to Markland et al. discloses a
`method and apparatus for measuring air in pneumatic
`tires. The system involves the use of first and second
`coils embedded in a portion of roadway over which the
`vehicle is driven and stopped upon. The first coil excites
`a primary receiving coil of a transducer embedded
`within the tire and thereby provides power to the trans-
`ducer. The transducer then measures the air pressure in
`the tire and produces an output signal which has a fre-
`quency proportional to air pressure in the tire. This
`output signal is received by the second coil in the road~
`way which is connected to a monitoring apparatus be»
`side the roadway. There is no mention that the device
`may be modified to permit monitoring of tire pressure
`and temperature while the vehicle is in use.
`The present invention seeks to solve the problem of
`monitoring tire pressure and temperature while the
`vehicle is in use.
`
`SUMMARY OF THE INVENTION
`
`In accordance with a broad aspect of the present
`invention there is provided a method and apparatus for
`measuring a physical quantity, property or condition
`and for transmitting a code representing the measured
`physical quantity, property or condition. The apparatus
`includes means for performing the following method
`steps
`a) developing a first signal in response to a physical
`quantity, property or condition;
`b) sampling the first signal to produce an instantaneous
`first signal value;
`c) assigning a first code to the instantaneous first signal
`value; and
`d) transmitting the first code for reception by a receiver.
`In accordance with the invention, the physical quan-
`tity, property or condition is sampled at a rate depend—
`ing upon whether or not the sampled value meets a
`given set of conditions,
`the sampling rate being in-
`creased when the sampled value is found to meet an
`adverse set of conditions.
`In accordance with another aspect of the invention,
`there is provided an apparatus including:
`(a) a pneumatic tire;
`(b) a transducer for developing a first signal in response
`to air pressure or air temperature within the tire;
`(c) sampling the first signal to produce an instantaneous
`first signal value;
`(d) assigning a first code to the instantaneous first signal
`value; and
`(e) transmitting the first code for reception by a re-
`ceiVer.
`
`In accordance with another aspect of the invention
`there is provided an apparatus and method for receiving
`transmitted codes from a remote device, the apparatus
`including means for performing the following method
`steps:
`
`Page 000048
`
`

`

`5,231,872
`
`3
`(a) receiving a received transmission having a received
`identifier, a received code and a re-synchronizing
`code:
`~
`(b) extracting and storing the received identifier and the
`received code from the received transmission;
`(c) determining which identifier has been received; and
`(d) displaying a representation of the received code
`while providing an identification of the received
`code.
`In accordance with another aspect of the invention
`there is provided a method and system for measuring a
`physical quantity, property or condition, transmitting a
`code representing the physical property, quantity or
`condition to a receiver and displaying a representation
`of the physical property, quantity or condition on a
`display at a central location. In accordance with an-
`other aspect of the invention there is provided an appa-
`ratus and method for receiving transmitted codes from
`a remote device,
`the apparatus including means for
`performing the following method steps:
`(a) developing a first signal in response to a physical
`quantity, property or condition;
`(b) sampling the first signal to produce an instantaneous
`first signal value;
`(c) assigning a first code to the instantaneous first signal
`value;
`(d) transmitting the first code for reception by a re-
`ceiver,
`(e) receiving the first code; and
`(t) producing signals in response to the first code to
`control a display device to display a representation of
`the first code.
`"
`In accordance with another aspect of the invention
`there is provided an apparatus and method for receiving
`transmitted codes from a remote device. the apparatus
`including means for performing the following method
`steps:
`(a) providing a plurality of measurement and transmis-
`sion circuits, each circuit:
`(i) developing a signal in response to a respective
`physical quantity, property or condition;
`(ii) sampling the signal to produce an instantaneous
`signal value;
`(iii) assigning a first code to the instantaneous signal
`value;
`_
`(iv) transmitting a transmission including the code
`and an identifier unique to the circuit;
`(b) receiving a received transmission from each of the
`measurement and transmission circuits;
`(c) extracting and storing the identifier and the code
`from the received transmission;
`(d) determining which identifier has been received; and
`(d) displaying a representation of the received code
`while providing an identification of the received
`code.
`In accordance with another aspect of the invention,
`there is provided an apparatus including:
`a) a body having connecting means for connecting the
`body to a valve stem of a tire and a chamber pressur-
`ized by air from the tire;
`b) measuring means for measuring an instantaneous
`value of air pressure in the chamber, the measuring
`means including sampling means for automatically,
`sampling the instantaneous value of the at least one
`operating parameter at regular intervals in time; and
`c) transmitting means for transmitting a representation
`of the instantaneous value and for transmitting an
`identification for identifying the transmitter.
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`4
`In accordance with another aspect of the invention,
`there is provided an apparatus and method of simulta-
`neously performing analog to digital conversion on a
`plurality of input signals, the apparatus including means
`for performing the following method steps:
`a) starting a voltage ramp generator circuit for produc-
`ing a ramp voltage;
`b) incrementing a digital counter at regular intervals in
`time while the ramp voltage is being generated;
`c) comparing each of the input signals to the ramp volt-
`age while the ramp voltage is being generated;
`d) loading an instantaneous count value from the
`counter into a parameter register corresponding to
`whichever input signal has a voltage less than the
`ramp voltage;
`e) repeating the steps of comparing and loading until the
`ramp voltage is greater than the voltage of each of
`the plurality of input signals.
`The invention addresses the problem of monitoring a
`physical property, quantity, or condition at a remote
`device and permits transmission of a code representing
`the monitored physical, quantity, or condition to a cen-
`tral receiving device, A plurality of monitoring devices
`may be used with a single receiver rendering an appara-
`tus according to the invention particularly useful in
`monitoring air pressures and temperatures of tires on a
`vehicle. The air pressure and air temperature of air
`within each tire on a vehicle such as a mining truck or
`semi-trailer unit can be monitored inside a cab portion
`of the vehicle to alert an operator to any potential prob-
`lems with the tires. Furthermore, as the code represent-
`ing the actual measured value is sent to the receiver, the
`receiver can display, in real time, a numerical indication
`of the air pressure or air temperature of a particular tire
`in units of pressure or temperature accordingly. Fur-
`thermore such indication can be provided while the
`operator is driving the vehicle, which eliminates the
`need to take the vehicle out of productive use to mea-
`sure air pressures or air temperatures.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`FIG. 1 is a perspective View of a mining truck on
`which an apparatus according to first embodiment of
`the invention is mounted;
`FIG. 2 is a perspective view of two tire units accord-
`ing to the invention shown mounted on a dual wheel
`assembly of the mining truck of FIG. 1;
`FIG. 3 is a cross-sectional view of a mounting bracket
`for mounting the tire unit of FIG. 2 onto the dual wheel
`assembly;
`FIG. 4 is a cross-sectional view of a tire unit accord-
`ing to the first embodiment of the invention;
`FIG. 5 is a functional block diagram of measurement
`circuitry according to the first embodiment of the in-
`vention;
`FIG. 6 is a flow diagram according to a main pro-
`gram executed on a first microcontroller according to
`the first embodiment of the invention;
`FIG. 7 is a memory map of registers used by the main
`program of FIG. 6;
`FIG. 8 is a memory map of registers used in connec-
`tion with an analog-to-digital conversion program ac—
`cording to the first embodiment of the invention;
`FIGS. 9A and 9B are first and second portions re-
`spectively of a flow diagram according to the analog-to-
`digital algorithm according to the first embodiment of
`the invention;
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`6
`FIG. 38 is a flow diagram of a register-to-table copy
`routine executed by the second microcontroller;
`FIG. 39 is a flow diagram of a pressure checking
`routine executed by the second microcontroller;
`FIG. 40 is a table copy routine executed by the sec-
`ond microcontroller;
`FIGS. 41A and 41B are first and second portions
`respectively of a flow diagram according to a compar-
`ing routine executed by the second microcontroller; and
`FIG. 42 is a flow diagram of an axle routine executed
`by the second microcontroller.
`FIG. 43 is a cross sectional View of a tire unit con-
`nected to a wheel, according to an alternative method
`of mounting the tire unit to the wheel.
`DETAILED DISCLOSURE
`
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`FIG. 10 is a flow diagram according to a unit conver-
`sion algorithm according to the first embodiment of the
`invention;
`FIG. 11 is a memory map of registers used by the unit
`conversion routine of FIG. 10;
`FIG. 12 is a flow diagram according to a comparing
`routine according to the first embodiment of the inven-
`tlon;
`FIG. 13 is a memory map of registers used by the
`comparing routine of FIG. 12;
`FIG. 14 is a memory map of fixed registers used by
`the comparing routine of FIG. 12;
`FIG. 15 is a flow diagram according to a sample save
`routine according to the first embodiment of the inven-
`tion;
`FIG. 16 is a memory map of registers used by a trans-
`mit routine according to the first embodiment of the
`invention;
`FIG. 17 is a flow diagram according to the transmit
`routine;
`FIG. 18 is a timing diagram of a tra