EP0199329A2 - Système de détection de véhicules - Google Patents

Système de détection de véhicules Download PDF

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Publication number
EP0199329A2
EP0199329A2 EP86105498A EP86105498A EP0199329A2 EP 0199329 A2 EP0199329 A2 EP 0199329A2 EP 86105498 A EP86105498 A EP 86105498A EP 86105498 A EP86105498 A EP 86105498A EP 0199329 A2 EP0199329 A2 EP 0199329A2
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EP
European Patent Office
Prior art keywords
vehicle
signal
vehicle detecting
coil
transmitting
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Application number
EP86105498A
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German (de)
English (en)
Other versions
EP0199329A3 (fr
Inventor
Masao Omron Tateisi Electronics Co. Mizuno
Tosihiko Omron Tateisi Electronics Co. Maruo
Takuya Omron Tateisi Electronics Co. Fujimoto
Seiichi Omron Tateisi Electronics Co. Sawada
Kenji Omron Tateisi Electronics Co. Kanayama
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Omron Corp
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Omron Tateisi Electronics Co
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Application filed by Omron Tateisi Electronics Co filed Critical Omron Tateisi Electronics Co
Publication of EP0199329A2 publication Critical patent/EP0199329A2/fr
Publication of EP0199329A3 publication Critical patent/EP0199329A3/fr
Withdrawn legal-status Critical Current

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    • G—PHYSICS
    • G08—SIGNALLING
    • G08G—TRAFFIC CONTROL SYSTEMS
    • G08G1/00—Traffic control systems for road vehicles
    • G08G1/01—Detecting movement of traffic to be counted or controlled
    • G—PHYSICS
    • G08—SIGNALLING
    • G08G—TRAFFIC CONTROL SYSTEMS
    • G08G1/00—Traffic control systems for road vehicles
    • G08G1/01—Detecting movement of traffic to be counted or controlled
    • G08G1/042—Detecting movement of traffic to be counted or controlled using inductive or magnetic detectors

Definitions

  • the present invention relates to a vehicle detecting system to detect the existence, passage, and the like of a vehicle.
  • This system is used in a traffic control system to smooth the traffic flow by, for example, counting the number of vehicles which pass a predetermined place on the road and controlling the signals on the basis of the count number obtained.
  • the loop coil has the size of about 2m x 2m and the road must be dug up over a wide range to bury such a large loop coil into the road.
  • Such a burying construction is a large-scaled, so that the construction expenses increase-and much labors are needed for the construction.
  • the loop coil buried under the road surface is frequently subjected to the loads in association with the passages of vehicles, so that the accident of disconnection of the coil is likely to occur.
  • the occurrence of the accident of the disconnection disenables the detection of vehicles.
  • a vehicle detecting system comprises: a transmitting coil arranged on one side of a predetermined detection area set on the roadway of vehicles and a receiving coil arranged on the opposite side of running direction of the vehicle. Further, those coils may be obliquely arranged with. respect: to those directions.
  • the vehicle detecting system in the case of detecting the vehicle on the basis of the variation in level: of: the; signal which is induced in the receiving coil, the following eactions are obtained. Namely, when the high frequency exciting current flows through the transmitting coil, the high frequency magnetic field is developed between the transmitting and receiving coils. When the vehicle passes in the magnetic field, the mutual inductance of both coils changes and the level of the electrical signal which is induced in the receiving coil changes.
  • This reception signal is inputted to the vehicle detecting circuit (vehicle detecting means) .
  • the change in the level of the reception signal is a predetermined amount or more, the vehicle detection signal is outputted from the vehicle detecting circuit.
  • the sizes of transmitting and receiving coils are extremely smaller than the conventional loop coil. Therefore, even when these coils are buried in the roadway as well, the burying construction can be simplified as compared with the conventional one. In addition, it is not always necessary to bury the transmitting and receiving coils to detect the vehicle but these coils may be also installed on the roadway. In this case, the installing construction can be further simplified.
  • the driving circuit and vehicle detecting circuit are enclosed in a box and this box is the transmitting coil; a driving circuit to supply a high frequency exciting current to the transmitting coil; and vehicle detecting means for outputting a vehicle detection signal in response to a change over a predetermined amount in the characteristic of an electrical signal which is induced in the receiving coil.
  • the characteristic of the electrical signal includes the level of the signal, phase of the signal, and the like.
  • the term "roadway” mentioned above denotes all of the locations where vehicles run and has the concept which apparently includes not only the ordinary road but also the road, floor and the like in the factories or precincts.
  • vehicle and “vehicles” also have the wide meaning including not only what are called four-wheeled automobiles but also tricycle type automobiles, two-wheeled type vehicles, bicycles, unmanned automobiles, travelling robot, and the like.
  • the transmitting and receiving coils may be buried under the roadway surface or may be set at positions of predetermind heights above the roadway.
  • the detection area. is the virtual area and is actually determined by the positions where the transmitting and receiving coils are arranged.
  • the transmitting and receiving coils may be provided at two positions along the running direction of the vehicle or may be provided at two positions which are away from each other at a predetermined distance in the direction perpendicular to the arranged on one side of the roadway, it is sufficient to bury one of the transmitting and receiving coils, e.g., the transmitting coil on this side and to bury the other coil, e.g., the receiving coil on the other side of the roadway or in the central portion thereof, or the like.
  • the signal line connecting the receiving coil and vehicle detecting circuit must be buried so as to cross the roadway, it is sufficient to dig up the roadway along only a signal line.
  • the driving circuit and transmitting coil are arranged on one side of the roadway and the receiving coil and vehicle detecting circuit are arranged on the other side, respectively, there is no need to arrange the signal line so as to cross the roadway.
  • the space between the transmitting and receiving coils becomes the vehicle detection area and this detection area can be set to a wide region. Therefore, the deterioration of the sensitivity as compared with that of the conventional loop coil is not caused.
  • F ig. 1 shows an example of an arrangement of a transmitting coil'2 and a receiving coil 4.
  • the coils 2 and 4 are wound around magnetic cores 2a and 4a, respectively, and buried on both sides in the lateral direction of a roadway (e.g., one lane of the road).
  • the sizes of cores 2a and 4a are relatively small; for example, the length is about 70 mm and the diameter is about l5mm.
  • the cores 2a and 4a are arranged so that their longitudinal directions are the vertical direction.
  • the distance between the transmitting coil 2 and the receiving coil 4 may be set to an arbitrary value and it will be ordinarily about one to a several meters.
  • the area between the coils 2 and 4 substantially serves as the vehicle detection area. Therefore, the vehicle detection area may be set to an arbitrary range and at an arbitrary location in accordance with the position where the coils 2 and 4 are arranged.
  • Either one of or both of the transmitting coil 2 and receiving coil 4 may be arranged on the roadway surface or may be also installed above the roadway surface (for example, at the position of height of about five meters) by a pole brace or the like which is vertically set on the roadway. Both coils 2 and 4 may be provided on one side of the roadway 1.
  • a high frequency exciting current is supplied from a driving circuit 3 to the transmitting coil 2.
  • the frequency of this exciting current may be set to a value in about a range from tens to hundreds of kHz. This frequency assumes f 0 .
  • the voltage or current which is induced in the receiving coil 4 by the high frequency electromagnetic field (mainly, the magnetic field) which is generated from the transmitting coil 2 is given to a vehicle detecting circuit 5 through a line 7 buried under the surface of the roadway 1.
  • the detecting circuit 5 detects in principle a change over a predetermined level in a reception signal of the receiving coil 4 and outputs a vehicle detection signal S.
  • the detecting circuit 5 always compares the level (or phase) of the signal from the driving circuit 3, namely, the level (or phase) of the current which is outputted to the transmitting coil 2 with the level (or phase) of the current which is inputted from the receiving coil 4.
  • the detecting circuit 5 When the difference between those levels (or phases) is over or below a predetermined value, the detecting circuit 5 outputs the vehicle detection signal S.
  • the driving circuit 3 and vehicle detecting circuit 5 are enclosed in a box 6 and this box is installed on the side or above the roadway 1.
  • the vehicle detection signal S is transmitted to a central controlling unit (not shown) through a telehpone line or another communication line or a transmitting line which is particularly installed.
  • the central controlling unit controls the flow of all vehicles in the whole range covered by the unit on the basis of the vehicle detection signals transmitted.
  • the high frequency exciting current flows through the transmitting coil 2 from the driving circuit 3, the high frequency magnetic field H is developed between the transmitting coil 2 and the receiving coil 4.
  • a vehicle C doesn't exist in the magnetic field H, there is no change in the level difference (or phase difference) between the transmitting current (exciting current) which is inputted to the detecting circuit 5 and the received current which is obtained in the receiving coil 4 1 so that the vehicle detection signal S is not outputted.
  • Fig. 3 shows an example of a more practical arrangemnt of the driving circuit 3 and vehicle detecting circuit 5 shown in Fig. 1.
  • F ig. 4 shows typical output signal waveforms in the circuit block shown in Fig. 3.
  • the driving circuit 3 of the transmitting coil 2 comprises a high frequency oscillating circuit 8 and a power amplifier 9 to amplify an oscillating output of the oscillator 8 and gives it to the transmitting coil 2.
  • the output current of the driving circuit 3 is not supplied to the detecting circuit 5.
  • the signal induced in the receiving coil 4 is amplified by an amplifier 11 and thereafter its noise component is removed by a band pass filter 12 having a center frequency of f 0 .
  • An output signal a of the filter 12 is detected by a detecting circuit 13 and becomes a signal b.
  • the signal b is sent to an analog switching circuit 14.
  • the first output side of the switching circuit 14 is grounded through a capacitor 16 and the second output side is grounded through a capacitor 17. Electrostatic capacitances of the capacitors 16 and 17 are equal. Positive terminals of the capacitors 16 and 17 are connected to the input terminals of a differential amplifier 18. respectively.
  • An output terminal of the differential amplifier 18 is connected to one input terminal of a comparator 19.
  • a constant voltage power supply 20 to generate a threshold voltage Vref is connected to the other input terminal of the comparator 19.
  • An output signal of the comparator 19 becomes the vehicle detection signal S.
  • the detection signal S is transmitted to an external apparatus, e.g., the central controlling unit (not shown) and also supplied to a timing curcuit 15 (as a signal g) .
  • a timing curcuit 15 (as a signal g) .
  • the timing circuit 15 outputs a pulse signal (a train of pulses) c to the switching circuit 14.
  • the output signal g of the comparator 19 is at a high lvel "H" (i.e., when the vehicle is detected)
  • the timing circuit 15 stops the generation of the pulse signal c.
  • the switching circuit 14 connects the detecting circuit 13 to the capacitor 16 when the pulse signal c from the timing circuit 15 is at an "H” level.
  • the switching circuit 14 connects the detecting circuit 13 to the capacitor 17 when the pulse signal c is at an "L" level.
  • the switching circuit 14, differential amplifier 18, capacitors 16 and 17 connected therebetween, and timing circuit 15 serve to detect the time-dependent change in the signal which is induced in the receiving coil 4 and operate in the following manner.
  • the switching circuit 14 Since the vehicle detection signal S is at an "L" level until time t 1 shown in Fig. 4, a series of pulses c are generated from the timing circuit 15. Therefore, the switching circuit 14 repeatedly performs the switching operation. Since the signal b of the same level is alternately supplied to the capacitors 16 and 17, charged voltages V 16 and V 17 of the capacitors 16 and 17 are equal and an output signal f of the differential amplifier 18 is at the zero level. The output signal g of the comparator 19 is held at an "L" level.
  • the level of the output signal b of the detecting circuit 13 starts increasing. Assuming that the pulse signal c rise at time t 1 , the detecting circuit 13 is connected to the capacitor 16. The level of the input signal d of the capacitor 16 increases by only an amount commensurate with the increased amount of the signal b. Thus, the output signal f of the differential amplifier 18 is slightly reduced.
  • the detecting circuit 13 When the pulse signal c trails at time t 2 , the detecting circuit 13 is connected to the capacitor 17. Since the level of the output signal b of the detecting circuit 13 increases for the period of time between times t 1 and t 2 , the level of the input signal e to the capacitor 17 largely increases. Thus, the level of the output signal f of the differential amplifier 18 exceeds the threshold voltage Vref and the output signal g of the comparator 19 becomes an "H" level. Due to this, the vehicle detection signal S at an "H" level is outputted and at the same time, the output signal g is inputted to the timing circuit 15. The generation of the pulse signal c from the timing circuit 15 is stopped. Thus, the switching operation of the switching circuit 14 is stopped at time t 2 . The connecting state of the detecting circuit 13 with the capacitor 17 is held.
  • the charged voltage V 16 of the capacitor 16 is held constant and at the same time, the level of the input signal e to the capacitor 17, namely, the charged voltage V l7 of the capacitor 17 changes in accordance with the level change of the output signal b of the detecting circuit 13.
  • the level of the output signal f of the differential amplifier 18 also similarly changes. Such a state continues for the period of time until the vehicle C has passed through the magnetic field H.
  • the generation of the vehicle detection signal S stops (i.e., the detection signal S becomes an "L” level) and the output signal g of the comparator 19 also becomes an "L” level.
  • the pulse signal c is sent from the timing circuit 15 to the switching circuit 14. The switching operation is restarted and the system is returned to the inherent switching state.
  • Figs. 5 to 7 show another embodiment in which the vehicle detecting process is executed by use of a microprocessor.
  • Fig. 5 shows an electrical arrangement of a vehicle detecting system, in which the same parts and components as those shown in Fig. 3 are designated by the same reference numerals.
  • the driving circuit 3 is additionally provided with an attenuator 31 and a band pass filter 32.
  • the oscillating output of the oscillator 8 is attenuated by the attenuator 31. Thereafter, the higher harmonic wave component is removed by the band pass filter 32. Thus, only the component of the frequency f 0 is sent to the power amplifier 9.
  • An amount of attenuation of the attenuator 31 is controlled by a microprocessor 21 as well be explained hereinafter in a manner such that the level of the rceived signal which is induced in the receiving coil 4 when no vehicle exists is always predetermined level.
  • the received signal of the receiving coil 4 was detected by the detecting circuit 13, its level is converted into a digital value by an analog-to-digital (A/D) converter 29 and supplied to the microprocessor 21.
  • A/D analog-to-digital
  • the level of the received signal converted into the digital value is referred to as the reception data hereinafter.
  • the microprocessor 21 comprises: a central processing unit (CPU) 22 to perform the control of the attenuator 31 and the like as well as the vehicle detecting process; a read only memory (ROM) 23 in which the programs which are executed by the CPU 22 are stored; a random access memory (RAM) 24 to store a reference value Va of the received signal level (i.e., reception data), attenuation amount of the attenuator 31, level of the received signal, threshold value Vth for detection of the vehicle, etc.; a timer 25; an interface 26 to take in the received signal; an interface 27 to control the attenuator; and an interface 28 to output the vehicle detection signal S.
  • CPU central processing unit
  • ROM read only memory
  • RAM random access memory
  • Fig. 6 shows a flowchart for the processing procedure by the CPU 22.
  • Fig. 7 shows time-dependent changes of various kinds of signals and values, respectively.
  • the attenuation amount of the attenuator 31 is set to the maximum value. Namely, the value of the exciting current flowing through the transmitting coil 2 (i.e., transmission level) is minimized (step 101).
  • the attenuation amount is stored into the RAM 24.
  • the reception data as the output value of the A/D converter 29 is supplied to the microprocessor 21 (step 102). This reception data is checked to see if it has reached the reference value Va corresponsing to a predetermined voltage which is required to detect the vehicle C or not (step 103).
  • step 104 the attenuation amount of the attenuator 31 is set to the value which is lower by only one unit (step 104) and then step 102 follows again.
  • the attenuation amount of the attenuator 31 is reduced in a stepwise manner, while the reception data increases step by step.
  • the attenuation amount stored in the RAM 24 is updated each time the above process is repeated.
  • the reception data becomes the reference value Va in time T 2 (namely, if YES in step 103)
  • the reception data is again supplied from the A/D converter 29 (step 105) and stored into a predetermined reception data area of the RAM 24 (step 106).
  • the idling is carried out for a predetermined period of time in step 107. Namely, the system waits for a sampling period which is determined by the timer 25.
  • reception data is further supplied (step 108) and the difference between this reception data and the precedent reception data which has been obtained one sampling before and which has been stored in the RAM 24 is calculated (step 109).
  • a check is then made to see if the difference exceeds the vehicle detection threshold value Vth or not (step 110).
  • the reception data supplied in step 108 is stored into the reception data area of the RAM 24 and the reception data is updated (step 111). This process is executed to cope with the time-dependent change in the level of the received signal. It is desirable to execute this updating process only in the case where the difference between the reception data supplied in step 105 and the present reception data supplied in step 108 is less than a predetermined value. Or, if the process in steps 101 to 106 is periodically executed when no vehicle exists, it is not always necessary to execute the updating process in step 111. Thereafter, the idling is performed (step 112) and the processing routine is returned to step 108. In this manner, the process in step 108 to 112 is repeated.
  • the vehicle detection signal S is outputted through the interface 28 (step 113).
  • the reception data is taken in (step 115).
  • the difference between this reception data and the reception data stored in the RAM 24 in step 106 or 111 is calculated and this difference is checked to see if it is below the threshold value Vth or not (step 116). If the difference still exceeds Vth, the process in steps 114 to 116 is repeated.
  • step 117 when the vehicle C has passed the detection area where the magnetic field H exists and the difference becomes smaller than the value Vth at time T 4 , the generation of the vehicle detection signal S is stopped (step 117). Thereafter, step 108 follows again.
  • the transmitting coil 2 is installed at the boundary portion of both roadways 1A and 1B and two receiving coils 4 are arranged on the outsides of the roadways 1A and 1B.
  • the vehicle detecting system can be also constituted such that one transmitting coil 2 is commonly. used to detect vehicles which pass two roadwaya 1A and 1B.
  • the longitudinal directions, i.e., the axes of the cores 2a and 4a of the transmitting and receiving coils 2 and 4 are vertically arranged.
  • the number of magnetic fluxes which interlink the receiving coil 4 due to the magnetic field H which is formed between the coils 2 and 4 is relatively large.
  • the number of magnetic fluxes which interlink the receiving coil 4 increases.
  • this increase amount is not so large, the sensitivity for detection of vehicles is not so high.
  • the magnetic field H is bent as shown in F ig. 9b and the density of magnetic fluxes interlinking the receiving coil 4 increases and at the same time, the number of interlinking magnetic fluxes remarkably increases.
  • the level of voltage which is induced in proportion to the change in number of interlinking magnetic fluxes also fairly increases as compared with the case of the arrangement shown in Figs. 2a and 2b (namely, it is increased at least about ten to hundred times) and the vehicle detecting sensitivity is sufficiently improved.
  • the following arrangement is preferable. Namely, briefly explaining, in the plane which is formed by the axis of the core of the transmitting coil 2 and the axis of the core of the receiving coil 4, it is sufficient to arrange the axis of the core 4a of the receiving coil 4 substantially perpendicularly with respect to the axis of the core 2a of the transmitting coil 2 or at an angle near it. Therefore, in the case where the axis of the core of the transmitting coil is vertically arranged and the axis of the core of the receiving coil is horizontally arranged, the sensitivity is improved.
  • the detecting sensitivity is improved.
  • Fig. 10 shows an electrical arrangement of the vehicle detecting system in the case where the transmitting coil 2 and receiving coil 4 arranged as explained above are used.
  • Fig. 11 is a flowchart showing the processing procedure by the CPU.
  • Fig. 12 shows the states of changes of signals, data, and values.
  • phase comparator a phase detector 36 is provided and the shifting direction of the phase of the received signal is discriminated. Therefore, it is possible to clearly distinguish whether the vehicle has passed the roadway having the vehicle detection area or it has passed the roadway adjacent thereto. Thus, only the vehicles which have passed the detection area can be accurately detected.
  • the vehicle detecting circuit 5 is newly provided with the phase comparator 36.
  • the transmitting signal which is supplied to the transmitting coil 2 and the received signal which is obtained from the receiving coil 4 are inputted to the phase comparaotr 36.
  • a signal indicative of the phase difference between those signals, more accurately speaking, a signal representative of an amount of phase shift of the received signal using the transmitting signal as the reference is outputted from the comparator 36.
  • the signal indicative of the phase difference is converted into a digital value by an analog-to-digital (A/D) converter 37 and thereafter it is supplied to the microprocessor 21.
  • a threshold value Vp of the phase difference to decide the vehicle detection is set in the RAM 24.
  • Fig. 11 the same processes as those shown in Fig. 6 are designated by the same reference numerals. Although the process in steps 101 to 104 in Fig. 6 is omitted from Fig. 11, this process is also similarly executed in the flowchart of F ig. 11. In addition, the updating process of the reception level data (the data which is obtained from the A/D converter 29) in step 111 is omitted in Fig. 11.
  • phase data of the receiving signal which is obtained from the A/D converter 37 is taken into the microprocessor 21 and stored into a predetermined area of the RAM 24 (steps 121 and 122).
  • step 110 When it is confirmed that the change amount of the reception level data has exceeded the threshold value Vth (step 110), an amount of change in the phase data is likewise derived (steps 123 and 124). A check is then mae to see if the change amount (difference) has exceeded the threshold value Vp in the negative direction or not (step 125). If YES, the vehicle detection signal S is outputted (step 113).
  • step 117 In the case of stopping the generation of the detection signal S as well (step 117), the AND logic is got between the signal indicating that the change amount of the level of the received signal became below the threshold value Vth (steps 115 and 116) and the signal representing that the change amount of the phase difference became below the threshold value Vp (in steps 126 to 128) .
  • the detecting circuit 13, A/D converter 29, and interface 26 may be omitted and the vehicle detection may be executed on the basis of only the phase difference of the received signal to the transmitting signal as well.
  • Figs. 13 and 14 relate to a developed system of the form shown in Fig. 8 and show a system to detect the vehicles which run a plurality of adjacent roadways, for example, a plurality of lanes.
  • Receiving coils 4A, 4B, and 4C and transmitting coils 2A and 2B are alternately arranged at the boundary portions of the respective lanes in the lateral directon of the lanes.
  • a high frequency signal which is generated from the oscillator 8 of the driving circuit 3 is sent to a change-over switch 42.
  • Amplifiers 9A and 9B to drive the transmitting coils 2A and 2B are connected to two output sides a and b of the switch 42, respectively.
  • the contact type change-over switch 42 has been shown, a contactless type switch composed of transistors and the like may be generally used.
  • the switch 42 is controlled by the CPU 22.
  • the receiving coils 4A, 4B, 4C are provided with amplifiers 11A, 11B, 11C and band pass filters 12A, 12B, and 12C, respectively.
  • An output of the filter 12A is supplied to a detecting circuit 13A and a phase comparator 36A.
  • outputs of the filters 12B and 12C are supplied to detecting circuits 13B and 13C and to phase comparators 36B and 36C, respectively.
  • Outputs of the detecting circuits 13A to 13C and outputs of phase comparators 36A to 36C are all supplied to a multiplexer 41 which is controlled by the CPU 22. These analog outputs are sequentially switched and converted into the digital signals by the A/D converter 29 and thereafter inputted to the CPU 22.
  • Vehicle detection signals S 1 to S 4 of the first to fourth lanes are individually outputted from the CPU 22.
  • the above-mentioned system operates in a manner as follows. First, the switch 42 is connected to the side a and the transmitting coil 2A is driven. In this case, the vehicles which pass the first and second lanes can be detected, so that the received signals of the receiving coils 4A and 4B are checked.
  • the output of the detecting circuit 13A is first taken into the CPU 22 through the multiplexer 41 and subsequently the output of the phase comparator 36A is taken into the CPU 22.
  • the process shown in Fig. ll, particularly, the process in steps 108 to 117 is executed by the CPU 22. If it is determined that the passage of the vehicle was detected, the vehicle detecting signal S 1 is outputted.
  • the switch 42 is connected to the side b and the transmitting coil 2B is driven.
  • the vehicle detecting processes for the third and fourth lanes are sequentially performed by checking the signals of the receiving coils 4B and 4C.
  • the vehicles in four lanes can be always detected.
  • Such an alternate arrangement of a plurality of transmitting and receiving coils may be installed in the running direction of the vehicle. With this arrangement, the running velocity of the vehicle can be measured using the difference of times of the vehicle is detected at respective positions. This arrangement can be also applied to detect the jam of vehicles.
  • Figs. 15 to 20 show further other embodiments. These embodiments relate to the systems which are useful to detect the jam of vehicles on the road, waiting states of vehicles at the toll station, running velocities of vehicles, and the like.
  • a plurality of transmitters 50 are arranged at regular intervals on one side along the road.
  • a plurality of receivers 60 are arranged at regular intervals on the other side along the road in corresopondence to the transmitters 50, respectively.
  • reference numbers one to n are added to-the transmitters 50.
  • the same reference numbers (Nos. 1 to n) are slso added to the receivers 60 corresponding to the transmitters 50, respectively.
  • These plurality of transmitters 50 are connected in a multidrop manner through one transmitting signal line, a plurality of (for examples in the case of four bits, four) designation signal lines and power supply lines to the box 6 equipped with the vehicle detecting system.
  • These plurality of receivers 60 are also likewise connected to the box 6 in a multidrop manner through one received signal line, a plurality of designation signal lines and power supply lines.
  • the interval of the transmitters 50 (and receivers 60) is set to 30 to 150 m in the case where, for example, the jam of vehicles is detected at the entrance and exit of an express highway or on the other ordinary road.
  • This interval is set to a small value of 0.5 to 1.0 m in the case of detecting the waiting state of vehicles at the toll station or parking lot. Namely, it may be set to a proper desired interval in accordance with a use object.
  • Fig. 16 shows an example of a constitution of the transmitter 50.
  • the transmitter 50 includes the transmitting coil 2.
  • the coil 2 is constituted by a resonance circuit on the secondary side and a primary coil to excite the resonance circuit.
  • the high frequency signal transmitted through the transmitting signal line is inputted to an amplifier 53 through a switch 52 consisting of -a semiconductor switching device or the like and the transmitting coil 2 is driven by the amplifier 53.
  • the designation signal of four bits is decoded by a decoder 51 and when this transmitter is designated, the switch 52 is turned on.
  • the receiver 60 similarly comprises: the receiving coil 4; an amplifier 63 to amplify the received signal of the coil 4; a switch 62 to connect an output of the amplifier 63 to the received signal line; and a decoder 61 to decode the designation signal and turn on the switch 62 when this receiver is designated.
  • Fig. 18 shows an electrical arrangement of the system built in the box 6.
  • the output of the driving circuit 3 is sent to the transmitting signal line.
  • the received signal line is connected to the amplifier 11.
  • the designation signal lines of four bits extend from the CPU 22 through an interface (not shown).
  • the designation signals on these lines are amplified by an amplifier 65 and thereafter supplied to all of the transmitters 50 and receivers 60.
  • the multiplexer 41 sequentially switched the level detection signal and phase difference signal of the received signal from the receiver and supplies them to the CPU 22.
  • each pair of transmitter and receiver is sequentially designated from No. 1 by the designation signal at every constant period of time (e.g., 8 msec).
  • the switch 52 is turned on by the decoder 51, so that the transmitting coil 2 is driven for only the designated time period.
  • the received signal of the receiving coil 4 is likewise sent to the vehicle detecting system through the received signal line for only the designated time period.
  • the CPU 22 processes the recived signals which are sequentially inputted, due to the foregoing method shown in Fig. 11 and the like, thereby determining the detection of the vehicle.
  • Fig. 20 shows an example of the vehicle detection signals in the respective detection areas.
  • the CPU 22 determines the velocity of the vehicle C and the stop state of the vehicle C on the basis of the time-dependent changes of the vehicle detection signals.
  • the difference of times when the detection of the existence of the vehicle C is started between the adjacent receivers is obtained. For example, the time difference between time t 1 when the detection of the existence of the vehicle C by the No. 1 receiver is started and time t 2 when the detection of the existence of the vehicle C by the No. 2 receiver is started, namely, (t 2 - t l ) is calculated. Or, the time difference of the vehicle detection between the Nos. 2 and 3 receivers, namely (t 3 - t 2 ) is calculated.
  • the running velocity of the vehicle C can be calculated by dividing the resultant time difference by the interval between the adjacent receivers installed.
  • the running velocity obtained is compared with a set value. When it is larger than the set value, it is decided that the vehicle C smoothly runs. If the velocity is smaller than the set value, on the contrary, it is determined that the vehicle C is in the jam state.
  • each of the transmitters and receivers is provided with the switch and decoder.
  • the switch and decoder may be provided for only either one of the transmitter and receiver.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Traffic Control Systems (AREA)
  • Geophysics And Detection Of Objects (AREA)
  • Train Traffic Observation, Control, And Security (AREA)
EP86105498A 1985-04-19 1986-04-21 Système de détection de véhicules Withdrawn EP0199329A3 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP84855/85 1985-04-19
JP60084855A JPS61243597A (ja) 1985-04-19 1985-04-19 車両感知器

Publications (2)

Publication Number Publication Date
EP0199329A2 true EP0199329A2 (fr) 1986-10-29
EP0199329A3 EP0199329A3 (fr) 1989-04-05

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EP86105498A Withdrawn EP0199329A3 (fr) 1985-04-19 1986-04-21 Système de détection de véhicules

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EP (1) EP0199329A3 (fr)
JP (1) JPS61243597A (fr)
KR (1) KR900005749B1 (fr)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2191299A (en) * 1986-06-02 1987-12-09 Shin Meiwa Ind Co Ltd Airplane taxiway position sensing apparatus
FR2639438A1 (fr) * 1988-11-21 1990-05-25 Cga Hbs Dispositif pour detecter des masses metalliques
CN102708687A (zh) * 2012-06-01 2012-10-03 辽宁机电职业技术学院 无线感应型道路车辆流量检测装置
CN103927870A (zh) * 2014-04-21 2014-07-16 哈尔滨工业大学 一种基于多个震动检测传感器的车辆检测装置
CN103971522A (zh) * 2014-05-23 2014-08-06 上海新中新猎豹交通科技股份有限公司 具有线圈切换扫描功能的线圈型车辆检测器及检测方法
CN111742356A (zh) * 2018-03-27 2020-10-02 株式会社京三制作所 检测系统
EP2923428B1 (fr) * 2012-11-12 2023-08-30 Auckland UniServices Limited Détection d'objet mobile ou de véhicule

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GB627053A (en) * 1946-08-26 1949-07-27 Cinema Television Ltd Improvements in or relating to apparatus for detecting the position of vehicles and the like
FR1346415A (fr) * 1962-11-07 1963-12-20 Cotonniere De Vagney Soc Procédé de détection à distance de masses métalliques, notamment de voitures automobiles, et dispositif pour son utilisation
JPS4523504Y1 (fr) * 1966-03-04 1970-09-16
JPS4523453Y1 (fr) * 1966-05-16 1970-09-16
US3911389A (en) * 1974-03-21 1975-10-07 Us Transport Magnetic gradient vehicle detector
DE2433241A1 (de) * 1974-07-11 1976-01-29 Elmeg Anordnung zur zaehlung von fahrzeugen, insbesondere von kraftfahrzeugen
GB1573673A (en) * 1977-05-05 1980-08-28 Philips Nv Vehicle detection system
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Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2191299A (en) * 1986-06-02 1987-12-09 Shin Meiwa Ind Co Ltd Airplane taxiway position sensing apparatus
FR2639438A1 (fr) * 1988-11-21 1990-05-25 Cga Hbs Dispositif pour detecter des masses metalliques
CN102708687A (zh) * 2012-06-01 2012-10-03 辽宁机电职业技术学院 无线感应型道路车辆流量检测装置
CN102708687B (zh) * 2012-06-01 2015-04-01 辽宁机电职业技术学院 无线感应型道路车辆流量检测装置
EP2923428B1 (fr) * 2012-11-12 2023-08-30 Auckland UniServices Limited Détection d'objet mobile ou de véhicule
CN103927870A (zh) * 2014-04-21 2014-07-16 哈尔滨工业大学 一种基于多个震动检测传感器的车辆检测装置
CN103927870B (zh) * 2014-04-21 2016-08-24 哈尔滨工业大学 一种基于多个震动检测传感器的车辆检测装置
CN103971522A (zh) * 2014-05-23 2014-08-06 上海新中新猎豹交通科技股份有限公司 具有线圈切换扫描功能的线圈型车辆检测器及检测方法
CN103971522B (zh) * 2014-05-23 2016-05-04 上海新中新猎豹交通科技股份有限公司 具有线圈切换扫描功能的线圈型车辆检测器及检测方法
CN111742356A (zh) * 2018-03-27 2020-10-02 株式会社京三制作所 检测系统
CN111742356B (zh) * 2018-03-27 2022-09-20 株式会社京三制作所 检测系统

Also Published As

Publication number Publication date
JPS61243597A (ja) 1986-10-29
EP0199329A3 (fr) 1989-04-05
KR900005749B1 (ko) 1990-08-09
KR860008521A (ko) 1986-11-15

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