Monitoring apparatus and control apparatus for traffic signal lights

• US 6,504,485 B2
• Filed: 01/09/2001
• Issued: 01/07/2003
• Est. Priority Date: 12/17/1996
• Status: Expired due to Fees

• Current Assignee: Nippon Signal Company Limited
• Original Assignee: Nippon Signal Company Limited
• Inventors: Asada, Norihiro, Fujimoto, Hidetoshi, Toda, Junya, Mazawa, Heisaku, Futsuhara, Koichi, Jinno, Yoshitaka, Okada, Norihiro, Ozaki, Yoshiharu
• Primary Examiner(s): Lieu, Julie
• Application Number:
  US09/756,267
• Publication Number:
  US 20020008629A1
• Time in Patent Office: 728 Days
• Field of Search: 340/907, 340/931, 340/642, 340/953, 340/458, 315/130
• US Class Current: 340/642
• CPC Class Codes: G08G 1/097 Supervising of traffic control systems, e.g. by giving an alarm if two crossing streets have green light simultaneously

Abstract

Monitoring and control apparatus for fail-safe monitoring for normal operation of traffic signal lights provided at an intersection or the like where a plurality of roads intersect. The illumination conditions of respective signal lights are detected using as sensor device, and when the number of illuminated or non-illuminated signal lights is a predetermined number, a normal judgment output of logic value 1 corresponding to a high energy condition is generated while, when the number of illuminated or non-illuminated signal lights is not the predetermined number, an abnormal judgment output of logic value 0 corresponding to a low energy condition is generated. As a result, when a fault in the monitoring apparatus stops the output, the resultant output condition is the same as for a danger condition due to a signal light abnormality, resulting in an extremely safe signal light monitoring and control with excellent fail-safe characteristics.

Claims

1. A monitoring apparatus for traffic signal lights comprising:

sensor means for detecting an illumination condition of traffic signal lights; and

judgment means for generating an output of logic value 1 corresponding to a high energy condition indicating a normal condition of the signal lights when, based on an output from said sensor means, the number of illuminated or non illuminated signal lights is a predetermined number, and generating an output of logic value 0 corresponding to a low energy condition indicating an abnormal condition of the signal lights when not the predetermined number,

wherein

said judgment means generates an output of logic value 1 when the number of illuminated signal lights is a predetermined number, and generates an output of logic value 0 indicating a signal light burn-out fault when not the predetermined number.

2. A monitoring apparatus for traffic signal lights according to claim 1, wherein said judgment means is constructed so as to respectively voltage doubler rectify and add the AC signals from said sensor means using voltage doubler rectifying circuits.

3. A monitoring apparatus for traffic signal lights according to claim 1, wherein

said sensor means is provided for each signal light, and is constructed so as to generate an AC signal at the time of illumination of the signal light, and not to generate an AC signal at the time of non illumination, and said judgment means is constructed so as to generate an output of logic value 1 when an addition signal level of the AC signals from the respective sensor means is a predetermined level, and to generate an output of logic value 0 when not the predetermined level, and

said judgment means judges said addition signal level using a window comparator which generates an output of logic value 1 when an input signal is within a previously set threshold value range, and which generates an output of logic value 0 when outside said threshold value range, and which gives an output of logic value 0 at the time of a fault.

4. A monitoring apparatus for traffic signal lights according to claim 1, wherein an output from said judgment means is sample held by an on-delay circuit having a delay time which is longer than an illumination period of said signal lights, and an output from said on-delay circuit is made a judgment output for a signal light burn-out fault.

5. A monitoring apparatus for traffic signal lights according to claim 1, wherein said high frequency signal generator is synchronized with an AC power supply for the signal light illumination, and is constructed such that said excitation signal is not produced close to a zero point of an AO signal from said AC power supply.

6. A monitoring apparatus for traffic signal lights according to claim 1, wherein said sensor means is a voltage sensor with a series circuit of a first photocoupler for switching an AC current from an illumination power source using a high frequency signal from a high frequency signal generator, and a second photocoupler for receiving an AC signal from the switched illumination power source, connected in parallel across the terminals of a switching circuit for signal light illumination which is connected in series with the signal light.

7. A monitoring apparatus for traffic signal lights according to claim 1, wherein said judgment means is constructed so as to respectively voltage doubler rectify and add the AC signals from said sensor means using voltage doubler rectifying circuits.

8. A monitoring apparatus for traffic signal lights according to claim 1, wherein

said sensor means is provided for each signal light, and is constructed so as to generate an AC signal at the time of illumination of the signal light, and not to generate an AC signal at the time of non illumination, and said judgment means is constructed so as to generate an output of logic value 1 when an addition signal level of the AC signals from the respective sensor means is a predetermined level, and to generate an output of logic value 0 when not the predetermined level, and

said judgment means judges said addition signal level using a window comparator which generates an output of logic value 1 when an input signal is within a previously set threshold value range, and which generates an output of logic value 0 when outside said threshold value range, and which gives an output of logic value 0 at the time of a fault.

9. A monitoring apparatus for traffic signal lights according to claim 1, wherein an output from said judgment means is sample held by an on-delay circuit having a delay time which is longer than an illumination period of said signal lights, and an output from said on-delay circuit is made a judgment output for a simultaneous illumination fault.

10. A monitoring apparatus for traffic signal lights wherein an illumination condition of respective signal lights for respective road directions of a two way intersection where two roads intersect is detected using sensor means which output a binary logic signal, generating an AC signal and outputting a logic value 1 when a signal light is illuminated, and not generating an AC signal and outputting a logic value 0 when the signal light is not illuminated, and wherein there is provided judgment means which, based on the output conditions from respective sensor means for each of the respective signal lights, generates an output of logic value 1 corresponding to a high energy condition when the signal lights are normal, and generates an output of logic value 0 corresponding to a low energy condition at the time of a simultaneous illumination of the signal lights where simultaneous illumination is not permitted.

11. A monitoring apparatus for traffic signal lights according to claim 10, wherein said judgment means comprises;

a first adding circuit for adding the logic signals of the respective sensor means for detecting an illumination condition of respective green lights indicating permission to proceed in the respective road directions, and a first level detection circuit for level detecting the addition value from said first adding circuit, the construction being such that said first level detection circuit generates an output of logic value 1 when the addition value is 1, and generates an output of logic value 0 when the addition value is 2.

12. A monitoring apparatus for traffic signal lights according to claim 10, wherein said judgment means comprises the first adding circuit and the first level detection circuit of claim 11, and further comprises:

a second adding circuit for adding the logical signals of the respective sensor means for detecting an illumination condition of respective red lights for the respective road directions;

a second level detection circuit for level detecting the addition value from said second adding circuit;

a third adding circuit for adding the logical signals of respective sensor means for detecting an illumination condition of yellow lights for the respective road directions and an output signal from ,said second level detection circuit; and

a first logical sum operation circuit for carrying out a logical sum operation on the addition value from said third adding circuit and an output from said first level detection circuit,

and the logical sum operation output is made a judgment output.

13. A monitoring apparatus for traffic signal lights according to claim 10, wherein said judgment means comprises the second adding circuit and the second level detection circuit of claim 12, and further comprises:

a fourth adding circuit for adding the logical signals of respective sensor means for detecting an illumination condition of green lights and yellow lights for the respective road directions; and

a second logical sum operation circuit for carrying out a logical sum operation on the addition value from said fourth adding circuit and an output from said second level detection circuit,

and the logical sum operation output is made a judgment output.

14. A monitoring apparatus for traffic signal lights wherein the signal lights for the same road side of a two way intersection where two roads intersect are made one group, and wherein for each group the illumination condition of a permit signal light indicating permission to proceed is detected using sensor means which outputs a binary logic signal, generating an AC signal and outputting a logic value 1 when a signal light is not illuminated, and not generating an AC signal and outputting a logic value 0 when the signal light is illuminated, and wherein there is provided judgment means which, based on the output conditions from the sensor means for each group, generates and output of logic value 1 corresponding to a high energy condition indicating the signal lights are normal, when at least one group shows a non illuminated condition, and generates an output of logic value 0 corresponding to a low energy condition indicating a simultaneous illumination fault when neither group shows a non illuminated condition,

wherein in the case of only one permit signal light for the respective groups, said judgment means comprises:

a fifth adding circuit for adding the logical outputs from the respective sensor means for each respective group; and

a third level detection circuit for level detecting the addition value from said fifth adding circuit, the construction being such that said third level detection circuit generates an output logic value 1 when the addition value is 1 or more and generates an output of logic value 0 when the addition value is zero.

15. A monitoring apparatus for traffic signal lights according to claim 14, wherein in the case of a plurality of permit signal lights for the respective groups, said judgment means comprises:

sixth and seventh adding circuits for respectively adding the logical outputs from the respective sensor means for each respective group;

fourth and fifth level detection circuits for respectively level detecting the addition values from said sixth and seventh adding circuits and outputting a logic value 1 when the addition values are respectively a maximum; and

a fourth logical sum operation circuit for carrying out a logical sum operation on both outputs from the fourth level detection circuit and the fifth level detection circuit,

and the logical sum operation output is made a judgment output.

16. A monitoring apparatus for traffic signal lights according to claim 14, wherein in the case of a plurality of permit signal lights for the respective groups, said judgment means comprises:

eighth and ninth adding circuits for respectively adding the logical outputs from the respective sensor means for each respective group;

a fifth logical sum operation circuit for carrying out a logical sum operation on the addition values from the eighth and ninth adding circuits; and

a sixth level detection circuit for level detecting the logical sum output from said fifth logical sum operation circuit and outputting a logic value 1 when the logical sum output is a logic value of 2 or more.

17. A monitoring apparatus for traffic signal lights according to claim 14, wherein said sensor means is a current sensor provided for each permit signal light, with a power supply line for the permit signal light wound around a saturable magnetic core such that an excitation signal for the saturable magnetic core input from a high frequency signal generator is received on an output side at a high level at the time of no power to said power supply line, and is received on the output side at a low level at the time of power supply.

18. A monitoring apparatus for traffic signal lights according to claim 17, wherein said high frequency signal generator is synchronized with an AC power supply for the permit signal light illumination, and is constructed such that said excitation signal is not produced close to a zero point of an AC signal from said AC power supply.

19. A monitoring apparatus for traffic signal lights according to claim 14, wherein said sensor means is a voltage sensor which detects a terminal voltage of an illumination switch circuit disposed in a power supply line for the permit signal light.

20. A monitoring apparatus for traffic signal lights according to claim 14, wherein in the case of a plurality of permit signal lights for the respective groups, then when said sensor means is constructed so as to generate an output of logic value 1 when all of the permit signal lights of the same group are not illuminated, and generate an output of logic value 0 when at least one of the permit signal lights is illuminated, then said judgment means carries out a logical sum operation on the outputs from the sensor means of the respective groups, and the logical sum operation output is made a judgment output.

21. A monitoring apparatus for traffic signal lights according to claim 20, wherein said sensor means is a current sensor with all power supply lines for the permit signal lights of the same group wound around one saturable magnetic core such that an excitation signal for the saturable magnetic core input from a high frequency signal generator is received on an output side at a high level when no current flows in said all power supply lines, and is received on the output side at a low level when a current flows in at least one power supply line.

22. A monitoring apparatus for traffic signal lights according to claim 20, wherein said sensor means is a voltage sensor which detects a terminal voltage of an illumination switch circuit disposed in a power supply line for the respective permit signal lights of the same group, and generates an output of logic value 1 when there is a terminal voltage for all of the signal lights, and gives an output of logic value 0 when there is not a terminal voltage for at least one of the signal lights.

23. A monitoring apparatus for traffic signal lights according to claim 22, wherein said sensor means is a voltage sensor with a series circuit of a first photocoupler for switching an AC current from an illumination power source using a high frequency signal from a high frequency signal generator, and a second photocoupler for receiving an AC signal from the illumination power source switched by the first photocoupler, connected in parallel across the terminals of an illumination switching circuit for one permit signal light, together with a plurality of series circuits constituted by photocouplers, each of which connected in parallel across the terminals of an illumination switching circuit for another permit signal light, with said second photocoupler and said series circuits of photocouplers cascade connected, and an output from the final stage series circuit made the sensor output.

24. A monitoring apparatus for traffic signal lights according to claim 14, wherein an output from said judgment means is sample held by an on-delay circuit having a delay time which is longer than an illumination period of said signal lights, and an output from said on-delay circuit is made a judgment output for a simultaneous illumination fault.

25. A monitoring apparatus for traffic signal lights according to claim 14, wherein a self-hold circuit is provided with the output from said judgment means as a reset input signal, and a signal light power source switch on signal as a trigger input signal, which self-holds said trigger input signal, and an output from said self hold circuit is made a judgment output for a simultaneous illumination fault.

26. A monitoring apparatus for traffic signal lights wherein in monitoring for a simultaneous illumination fault of the signal lights of a three way intersection where three roads intersect, the signal lights for the same road are made one group, and wherein for each group, the illumination condition of a permit signal light indicating permission to proceed is detected using sensor means which outputs a binary logic signal, generating an AC signal and outputting a logic value 1 when a signal light is not illuminated, and not generating an AC signal and outputting a logic value 0 when the signal light is illuminated, and wherein there is provided:

tenth, eleventh and twelfth adding circuits for respectively adding the logical signals from the sensor means for each group;

seventh, eighth and ninth level detection circuits for respectively level detecting the addition values from the respective adding circuits and generating an output of logic value 1 when the respective addition values are a maximum;

a thirteenth adding circuit for adding the logical outputs from the respective level detection circuits; and

a tenth level detection circuit for outputting a logic value 1 indicating normal signal lights when the addition value of the thirteenth adding circuit is 2 or more, and generating an output of logic value 0 indicating a simultaneous illumination fault when the addition value is 1 or less.

27. A monitoring apparatus for traffic signal lights wherein in monitoring for a simultaneous illumination fault of the signal lights of a three way intersection where three roads intersect, the illumination condition of the respective permit signal lights indicating permission to proceed is respectively detected using sensor means which output a binary logic signal, generating an AC signal and outputting a logic value 1 when a signal light is not illuminated:

and not generating an AC signal and outputting;

a logic value 0 when the signal light is illuminated, and wherein there is provided;

a fourteenth adding circuit for adding the sensor outputs corresponding to the respective permit signal lights for the first direction and second direction roads;

a fifteenth adding circuit for adding the sensor outputs corresponding to the respective permit signal lights for the second direction and third direction roads;

a sixteenth adding circuit for adding the sensor outputs corresponding to the respective permit signal lights for the third direction and first direction roads; and

an eleventh level detection circuit for generating an output of logic value 1 indicating normal signal lights when the addition value of the respective adding circuits is 6, and generating an output of logic value 0 indicating a simultaneous illumination fault when the addition value is 5 or less.

28. A control apparatus for traffic signal lights, incorporating an illumination control circuit for controlling the illumination of signal lights of respective signal light units installed at an intersection where several roads intersect, said control apparatus comprising:

a signal light monitoring circuit provided with, sensor means for detecting an illumination condition of respective signal lights, and judgment means for generating an output of logic value 1 corresponding to a high energy condition indicating a normal condition of the signal lights when, based on an output from said sensor means, the number of illuminated or non illuminated signal lights is a predetermined number, and generating an output of logic value 0 corresponding to a low energy condition indicating an abnormal condition of the signal lights when the number is not the predetermined number; and

a signal light power supply control circuit which supplies power to the signal lights when an output of logic value 1 is generated from said signal light monitoring circuit, and which stops power supply to the signal lights when an output of logic value 0 is generated.

29. A control apparatus for traffic signal lights according to claim 28, wherein said signal light monitoring circuit comprises:

sensor means constructed so as to generate an AC signal at the time of non illumination of a signal light, and not to generate an AC signal at the time of illumination; and

judgment means which generates an output of logic value 1 when the number of non illumination outputs from said sensor means is a predetermined number, and generates an output of logic value 0 indicating a signal light simultaneous illumination fault where simultaneous illumination is not permitted, when not the predetermined number.

30. A control apparatus for traffic signal lights according to claim 29, wherein said signal light power supply control circuit has an electromagnetic relay having relay contact points disposed in series in the power supply lines for the respective signal lights, the construction being such that said electromagnetic relay is placed in a non excited condition with said contact points open, based on an output of logic value 0 indicating simultaneous illumination from said signal light monitoring circuit.

31. A control apparatus for traffic signal lights according to claim 30, wherein said signal light power supply control circuit incorporates:

a signal light flash command circuit which outputs to an illumination control circuit, a flash command for a yellow light and a red light for intersecting roads when an output of logic value 0 indicating simultaneous illumination of the signal lights is generated from the signal light monitoring circuit so that the output from said first self-hold circuit is cancelled;

a flash monitoring circuit for monitoring if a flash operation of said yellow light and red light is normal, based on the flash command from said signal light flash command circuit; and

an electromagnetic relay control circuit which de-energizes said electromagnetic relay to open the contact points and stop the signal light power supply, when based on an output from said flash monitoring circuit the flash operation for said yellow light and the red light is abnormal.

32. A control apparatus for traffic signal lights according to claim 31, wherein said electromagnetic relay control circuit comprises a second self-hold circuit with a signal for a fall in the output of logic value 1 from said signal light monitoring circuit as a trigger input signal, and monitoring output from said flash monitoring circuit as a reset input signal, the construction being such that when the flash operation for the yellow light and the red light is normal at the time of signal light simultaneous illumination, the trigger input signal and the reset input signal both become a logic value 1 so that the excitation of the electromagnetic relay is maintained by means of an output from said second self-hold circuit.

33. A control apparatus for traffic signal lights according to claim 31, wherein said flash monitoring circuit uses two current sensors each with a power supply line for a signal light wound around a saturable magnetic core such that an excitation signal for the saturable magnetic core input from a high frequency signal generator is received on an output side at a high level at the time of no power to said power supply line, and is received on the output side at a low level at the time of power supply, the construction being such that the power supply line for the red light is wound around the saturable magnetic core of one current sensor, and the power supply line for the yellow light is wound around the saturable magnetic core of the other current sensor, and a logical sum operation is carried out on envelope detection output signals for the high frequency output signals of the respective current sensors, and when the logical sum operation output is a logic value of 1, then the flashing of the red and yellow lights is normal, and when the logical value is 0, the flash operation is abnormal.

34. A control apparatus for traffic signal lights according to claim 31, wherein said flash monitoring circuit uses one current sensor with a power supply line for a signal light wound around a saturable magnetic core such that an excitation signal for the saturable magnetic core input from a high frequency signal generator is received on an output side at a high level at the time of power to said power supply line, and is received on the output side at a low level at the time of no power supply, the construction being such that the red light and yellow light power supply lines are wound around the saturable magnetic core of the current sensor, and a threshold value operation is carried out on an envelope detection output signal for the high frequency output signal of the current sensor with a window comparator, and when the envelope detection output signal is within a predetermined threshold value range the flash operation is normal, and when outside of the threshold value range the flash operation is abnormal.

35. A monitoring apparatus for traffic signal lights comprising:

respective saturable magnetic cores with respective signal light power supply lines provided for each of a plurality of signal lights connected in parallel with each other to a common power supply line, wound thereon as primary windings;

a transformer with second windings for impedance detection wound on said respective saturable magnetic cores and connected in series with each other, acting as load for a secondary winding thereof and which receives a high frequency signal from a high frequency signal generator in a primary winding thereof; and

a level detection circuit which generates an output of logic value 1 indicating normal signal lights when an output signal level of said transformer is equal to or above a predetermined level as a result of an output signal change due to a change in impedance for said transformer, and generates an output of logic value 0 indicating a signal light burn-out fault when lower than the predetermined level.

36. A monitoring apparatus for traffic signal lights according to claim 35, wherein a logical product operation is carried out on the logical output from said level detection circuit and a sensor output from sensor means which generates an output of logic value 1 when said plurality of signal lights are illuminated, and when the logical product operation value is a logic value 1 the signal lights are normal.

37. A monitoring apparatus for traffic signal lights according to claim 35, wherein said level detection circuit comprises a window comparator with the output signal from said transformer as the input to one input terminal and a sensor output from a sensor means which generates an AC signal of a high level when there is a current in said common power supply line as the input to the other input terminal, the construction being such that said window comparator generates an output of logic value 1 indicating normal signal lights when a high level AC signal is input to said other input terminal, and an output signal level equal to or above a previously set threshold value is input to said one input terminal.

38. A monitoring apparatus for traffic signal lights, wherein an illumination condition of respective signal lights of an intersection where a plurality of roads intersect is detected using:

sensor means which generate an AC signal at the time of non illumination of a signal light and which do not generate an AC signal at the time of illumination of the signal light, and wherein an AC signal level at the time of non illumination from a sensor means for detecting the illumination condition of a vehicle green light and a pedestrian green light, is made different from an AC signal level at the time of non illumination from a sensor means for detecting an illumination condition of a yellow light, and wherein there is provided judgment means which, based on the outputs from the respective sensor means, distinguishes and warns between respective simultaneous illumination faults of the vehicle green light pairs and the vehicle green lights and the pedestrian green lights, and respective simultaneous illumination faults of the vehicle green lights and the yellow lights and the pedestrian green lights and the yellow lights.

39. A monitoring apparatus for traffic signal lights according to claim 38, wherein for the case of a three way intersection where three roads intersect, a plurality of current sensors are used for said sensor means, each with a power supply line for the signal light wound around a saturable magnetic core such that an excitation signal for the saturable magnetic core input from a high frequency signal generator is received on an output side at a high level at the time of no power to said power supply line, and is received on the output side at a low level at the time of power supply, the construction being such that two output terminals are provided for each current sensor, and power supply lines for a vehicle green light and a pedestrian green light for a first road direction are wound on a first current sensor, and a power supply line for a yellow light for the first road direction is wound on a second current sensor, and power supply lines for a vehicle green light and a pedestrian green light for a second road direction are wound on a third current sensor, and a power supply line for a yellow light for the second road direction is wound on a fourth current sensor, and power supply lines for a vehicle green light and a pedestrian green light for a third road direction are wound on a fifth current sensor, and a power supply line for a yellow light for the third road direction is wound on a sixth current sensor, and the output levels of the first, third, and fifth current sensors are made different from the output levels of the second, fourth, and sixth current sensors, and said judgment means comprises:

a fifteenth adding circuit for adding the output signals from one output terminal of the first and second current sensors and the output signals from one output terminal of the third and fourth current sensors;

a sixteenth adding circuit for adding the output signals from the other output terminal of the first and second current sensors and the output signals from one output terminal of the fifth and sixth current sensors;

a seventeenth adding circuit for adding the output signals from the other output terminal of the third and fourth current sensors and the output signals from the other output terminal of the fifth and sixth current sensors; and

two window comparators which generate a high level output of logic value 1 when a logical sum output for the addition output levels of the fifteenth, sixteenth and seventeenth adding circuits is equal to or greater than a previously set threshold value, the construction being such that

the threshold value of one window comparator is set so as to detect a drop in the output from said first, third and fifth current sensors, and the threshold value of the other window comparator is set so as to detect a drop in the output from said second, fourth and sixth current sensors.

40. A monitoring apparatus for traffic signal lights, wherein in monitoring for simultaneous illumination faults in traffic signal lights, illumination is controlled with the green, red and yellow signal lights of respective signal units for an intersection where a plurality of roads intersect, connected in parallel with one common power supply line, the construction being such that current sensors are used, each with the power supply line for the signal light wound on a saturable magnetic core such that an excitation signal for the saturable magnetic core input from a high frequency signal generator is received on an output side at a high level at the time of no power to said power supply line, and is received on the output side at a low level at the time of power supply, and the common power supply lines for the signal units and the red light power supply lines are wound in opposite directions to each other on the saturable magnetic cores of the respective current sensors provided for each signal unit for the respective road directions, and the AC signal level of the respective current sensors is added by an adding circuit, and the added signal level is detected by a level detection circuit, said level detection circuit generating an output of logic value 1 indicating normal when the addition signal level is equal to or above a previously set predetermined level, and generating an output of logic value 0 indicating a simultaneous illumination fault when lower than the predetermined level.

41. A control apparatus for traffic signal lights wherein in controlling the illumination of signal lights for a two way intersection where two roads intersect, the illumination condition of respective permit signal lights for permitting traffic to proceed in the respective road directions is detected using sensor means which generate an AC signal at the time of non illumination of the signal lights and which do not generate an AC signal at the time of illumination, and wherein there is provided:

a first electromagnetic relay which is excited by an output signal from a first sensor means for detecting an illumination condition of a permit signal light on one road; and

a second electromagnetic relay which is excited by an output signal from a second sensor means for detecting an illumination condition of a permit signal light on the other road, and wherein relay contact points for closing a circuit at the time of excitation of the second electromagnetic relay are disposed in series in a power supply line for the permit signal light for the one road, and relay contact points for closing a circuit at the time of excitation of the first electromagnetic relay are disposed in series in a power supply line for the permit signal light for the other road.