Signal Control System

Abstract

To provide a signal control system for adequately determining a recognized signal standby body as a fixed obstacle without repeating useless lighting intervention control with respect to the signal standby body.SOLUTION: An ultrasonic sensor 30 can detect an object to approach a detection area R from a temporal difference of transmitted / received ultrasonic waves, and can recognize that the object is a signal standby body M when the object entering the detection area R is continuously detected at the same position for a predetermined time. After the recognition, lighting intervention control to perform blue lighting is performed with respect to a signal lamp 20 which allows the signal standby body M to stop at the signal lamp. When the detection of the signal standby body M continues after the end of the blue lighting of the signal lamp 20 during the lighting intervention control or after the lighting intervention control, the object is determined to be a fixed obstacle M so as to be excluded from a detection object of the ultrasonic sensor 30.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a signal control system that uses an ultrasonic sensor to recognize a waiting signal object and perform lighting intervention control for a signal lamp. [Background technology]

[0002] Patent Document 1 discloses a pedestrian detection device that is installed on a road near a crosswalk, which detects a detected object as a pedestrian crossing if the detected object remains stopped within an arbitrary area range within a certain region for a first set time or longer, and determines that the object is a fixed obstacle and excludes it from detection targets if the detected object continues to exist for a second set time that is longer than the first set time. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2001-256590 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, when a pedestrian waits to cross a crosswalk, the time it takes for the light to turn green varies greatly depending on the number of seconds set on the crosswalk's signal controller and the timing of when the pedestrian enters the crosswalk area.

[0005] If the above-mentioned second set time is set to a short time, a pedestrian waiting to cross may be mistakenly determined to be a fixed obstacle. Therefore, in Patent Document 1, the second set time is set to a long time of 5 minutes, which makes it possible to prevent a pedestrian from being mistakenly determined to be a fixed obstacle. However, if a fixed obstacle is present, the green light intervention control is repeated for 5 minutes, which creates the problem of having to carry out unnecessary light intervention control even when no pedestrian is present.

[0006] Therefore, it is preferable to set the second set time to an appropriate time based on the traffic light period, etc., but this poses the problem that an appropriate time must be set individually for each traffic light, making the setting process cumbersome.

[0007] An object of the present invention is to solve the above-mentioned problems and provide a signal control system that accurately determines that a recognized signal waiting object is a fixed obstacle without repeating unnecessary lighting intervention control. [Means for solving the problem]

[0008] In order to achieve the above object, a signal control system according to the present invention provides a detection area for a waiting area at an intersection, and the system includes an ultrasonic sensor that emits ultrasonic waves into the detection area and measures the reflected waves of the ultrasonic waves, and a control unit that is connected to the ultrasonic sensor and controls the lighting of a signal lamp. When an object is detected within the detection area by the ultrasonic sensor for a predetermined continuous period of time while a signal lamp for crossing the intersection or for entering the intersection is lit red, the control unit recognizes the object as a signal waiting object and controls the signal lamp to The red light will turn to blue light. Perform lighting intervention control, The above End of blue light At times, If the detection of the signal waiting object continues within the detection area, the object is determined to be a fixed obstacle and is excluded from the detection targets of the ultrasonic sensor. If the time difference between the ultrasonic waves successively measured by the ultrasonic sensor after the determination is within a predetermined time width, that is, a fluctuation width, the determination that the obstacle is a fixed obstacle is continued, and if the time difference falls outside the fluctuation width based on a change in the posture of the pedestrian, the determination that the obstacle is a fixed obstacle is cancelled. The present invention is characterized by the above. Effect of the Invention

[0009] According to the signal control system of the present invention, when an object detected in the detection area by the ultrasonic sensor is recognized as a waiting signal object, the light intervention control is executed. Then, when the signal lamp that was recognized in the detection area continues to be recognized after the green light of the signal lamp during the light intervention control ends or after the light intervention control, the detected object is determined to be a fixed obstacle and is excluded from the detection target by the ultrasonic sensor. By processing in this manner, it is possible to prevent the light intervention control that turns on the green light of the signal lamp that is waiting for the signal to be changed to a fixed obstacle such as a bicycle parked in the detection area or a parked motorcycle from being erroneously recognized as a waiting signal object that is a pedestrian waiting to cross or a vehicle waiting for the signal to change to a different signal from the fixed obstacle. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a system configuration diagram of a signal control system. [Diagram 2] FIG. 13 is an explanatory diagram of an indication table after lighting intervention control. [Diagram 3] FIG. 13 is an explanatory diagram of an indication table before lighting intervention control. [Figure 4] 11 is a flowchart of the control of the control unit to intervene in lighting of a signal lamp. FIG. [Diagram 5] FIG. 13 is a flowchart of a sub-process of the signal lamp lighting intervention control. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Fig. 1 is a system configuration diagram of a signal control system, which is installed at an intersection C1 consisting of a main road S1 and a secondary road S2 that intersects with the main road S1 in a T-shape. Note that the intersection C1 is just one example, and the signal control system may be installed at an intersection C where only pedestrian signal lamps are provided on the main road S1.

[0012] The traffic light control system is composed of traffic lights 10, 20 respectively arranged on a main road S1 with heavy traffic and a secondary road S2 with light traffic, an ultrasonic sensor 30 provided above a waiting area for pedestrians, vehicles, etc. at intersection C1, and a control unit 40 connected to the traffic lights 10, 20 and each ultrasonic sensor 30 and controlling the lighting of the traffic lights 10, 20 in accordance with a phase table T described later.

[0013] At intersection C1, a signal light system 10 consisting of a vehicle signal light 11 is installed on main road S1, and a signal light system 20 consisting of a vehicle signal light 21 and a pedestrian signal light 22 is installed on secondary road S2.

[0014] These vehicle signal lights 11, 21 turn on red, yellow and blue lights for vehicles traveling on the main road S1 and the secondary road S2, and the pedestrian signal light 22 turns on or flashes red and blue lights for pedestrians crossing the crosswalk H. In other words, the vehicle signal lights 11, 21 are signal lights for vehicles such as automobiles and motorcycles entering the intersection, and the pedestrian signal light 22 is a signal light for pedestrians crossing the intersection.

[0015] The ultrasonic sensor 30 is composed of a pedestrian ultrasonic sensor 31 whose detection area R1 is a waiting area for pedestrians waiting to cross near the crosswalk H, and a vehicle ultrasonic sensor 32 whose detection area R2 is a waiting area on the secondary road S2 where automobiles and motorcycles entering the main road S1 from the secondary road S2 wait for the traffic light.

[0016] As shown in the figure, the detection area R1 exists at the four corners of the intersection C1. Depending on the shape of the intersection C, the pedestrian ultrasonic sensor 31 and / or the vehicle ultrasonic sensor 32 will be appropriately positioned.

[0017] The ultrasonic sensor 30 is mounted on an arm extending horizontally from a pillar on which the signal lamps 10, 20 are mounted, and the orientation of the head of the ultrasonic sensor 30 (not shown) is adjusted so that the detection area R is located below. This head has the function of emitting ultrasonic waves with an elliptical emission range and receiving reflected waves, and is capable of detecting an object entering the detection area R from the time difference between the transmitted and received ultrasonic waves. In other words, when an object enters the detection area R, a reflected wave with a reflection time that is shorter than the reflection time of the reflected wave from the ground and that corresponds to a predetermined height is input to the ultrasonic sensor 30, and the object can be detected.

[0018] It is also possible to install the head unit at an appropriate height for the ultrasonic sensor 30 so as to transmit and receive ultrasonic waves with an elliptical emission range in the horizontal direction. When emitting ultrasonic waves in the horizontal direction in this way, a detection distance of, for example, 5 m is set as the detection area R, and it is determined that an object has been detected within the detection area R if the distance is within 5 m based on the reflection time of the reflected wave.

[0019] In addition, the detection area R of the ultrasonic sensor 30 may be set to an approximately circular area with a radius of about 4 m, and ultrasonic waves emitted in a spot shape may be scanned over a surface to detect an object that has entered the detection area R and to identify the position of the object.

[0020] The control unit 40 is housed in a box-shaped housing fixed to one of the pillars on which a pair of vehicle signal lights 11 are installed at intersection C1, for example, and various setting operations can be performed by opening an openable door provided on the front of the housing.

[0021] All of the traffic lights 10, 20 and the ultrasonic sensor 30 installed at the intersection C1 are connected to the control unit 40 as shown by the connection line in the upper left of Fig. 1. Note that lines other than the connection line in the upper left are not shown, and communication between the control unit 40 and the ultrasonic sensor 30 may be either wireless communication or wired communication.

[0022] 2 and 3 are explanatory diagrams of the aspect table T1 and the aspect table T2 stored in the control unit 40. The straight lines shown in these aspect tables T represent a green light being lit, the dotted lines represent a flashing green light, the wavy lines represent a yellow light being lit, and the double lines represent a red light being lit.

[0023] The indication table T is made up of a number of stairs K, and after the power supply to the control unit 40 is turned on and all the signal lamps are turned on red, the lighting control of the signal lamps 10 and 20 is performed according to the hold time in the order of stairs K1, K2, and K3, which are the first stairs K, up to stairs K8. Then, after the final stairs K8, the lighting control returns to stairs K1, which is the first stairs K, and the stairs K are sequentially repeated.

[0024] The total value of the number of seconds to maintain the lighting time for each of the levels K1 to K8, in other words, the time it takes for the traffic light to complete one cycle, is defined as the cycle Cy. The number of seconds to maintain each of the levels K1 to K8 is a fixed number of seconds, or an upper and lower limit number of seconds for maintaining the minimum lighting, defined according to the size, traffic volume, and occupancy rate of the intersection C, and an upper limit of the cycle Cy is defined as, for example, 240 seconds. Within the range of these definitions, the number of seconds to maintain each of K1 to K8 is set as appropriate.

[0025] At a normal intersection C, pedestrian signal lights are also provided for the main road S1, and the control unit 40 alternately controls the lighting of the signal lights 10, 20 at the intersection C according to a stage K that includes these pedestrian signal lights.

[0026] At intersection C1, the above-mentioned alternating lighting control of the signal lamps 10 and 20 is not performed, and when a signal waiting object M described later is not detected, the control unit 40 continuously lights up step K1 of the indication table T1, that is, controls the lighting according to the indication table T2 in which the signal lamp 20 is always lit in red.

[0027] The number of seconds for which the stairs K1 to K8 in the aspect table T2 are held is the same as the number of seconds for which the stairs K1 to K8 in the aspect table T1 are held, and the stairs K2 to K8 in the aspect table T2 are controlled to be illuminated in the same manner as the stairs K1.

[0028] Then, depending on the timing at which the object detected by the ultrasonic sensor 30 is recognized as a signal waiting object M, intervention lighting control is performed, including output from the lighting control of the indication table T2 to steps K2 to K8 of the indication table T1.

[0029] In the output state of the aspect table T2 shown in Fig. 3, for example, when the pedestrian ultrasonic sensor 31 recognizes a pedestrian waiting for a traffic light M at timing B1 on staircase K1, the lighting control is switched to that of the aspect table T1 from staircase K2, and the signal lamp 20 starts to light green after a waiting time Wt1. Then, the pedestrian signal lamp 22 switches from red to green, allowing the pedestrian to cross the crosswalk H.

[0030] In addition, in the lighting control state based on the indication table T2 shown in Figure 3, if the ultrasonic sensor 30 recognizes a signal waiting object M at a timing other than the step K1, such as timing B2, lighting control is performed to turn the vehicle signal lamps 11 on the main road S1 on red, but this is too late within the current cycle Cy.

[0031] Therefore, at step K2 of the next cycle Cy, the lighting control is switched from the lighting control of the aspect table T2 to the lighting control of the aspect table T1. That is, after a waiting time Wt2 that is extra long by about one cycle, the green lighting of the signal lamp unit 20 is started.

[0032] In this way, the waiting time Wt varies greatly depending on the detection timing of the ultrasonic sensor 30. Also, the light intervention control that temporarily switches the aspect table T2 to the aspect table T1 based on the recognition of the waiting signal object M by the ultrasonic sensor 30 and turns the signal lamp 20 green based on the aspect table T1 will return to normal operation based on the aspect table T2 when the waiting signal object M is no longer recognized.

[0033] Fig. 4 is a flowchart of the lighting intervention control of the signal lamps 10 and 20 by the control unit 40, and Fig. 5 is a flowchart of a sub-process of the lighting intervention control of the signal lamps. According to these flowcharts, during the execution of normal lighting control of the signal lamps based on the aspect table T2, a process of switching to lighting intervention control based on the aspect table T1 is executed.

[0034] At the intersection C1, lighting control based on the aspect table T2 is normally executed, and the vehicle signal lamp 11 is lit green, and the vehicle signal lamp 21 and the pedestrian signal lamp 22 are lit red.

[0035] When the control unit 40 starts the flow chart shown in Fig. 4, in step ST11 it is determined whether the signal lamp 20, i.e., the vehicle signal lamp 21 or the pedestrian signal lamp 22, is in a red light state, and if it is in a red light state, the process proceeds to step ST12. If the signal lamp 20 is not in a red light state, the process of step ST11 is repeatedly executed until it is in a red light state. Note that, at the start of the lighting control by the control unit 40, the vehicle signal lamp 21 and the pedestrian signal lamp 22 are in a red light state based on the lighting control of the current indication table T2, so that the process always proceeds to step ST12 in the initial process.

[0036] In step ST12, it is determined whether or not a signal waiting object M has been recognized within the detection area R. Whether or not a signal waiting object M has been recognized is determined based on whether or not an object that has entered the detection area R is detected by the ultrasonic sensor 30 at the same position for a predetermined period of time, for example, 3 seconds or more. When an object that has entered the detection area R is detected at the same position for a predetermined period of time, for example, 3 seconds or more, this object is recognized as a signal waiting object M, which is a pedestrian or vehicle waiting for the traffic light to change.

[0037] In addition, the recognition process for this signal waiting object M considers the point at which the time difference between the ultrasonic waves transmitted and received by the head unit changes to be shorter as the start point of object detection, and the point at which the time difference returns to the point before the change as the end point of object detection.

[0038] In this way, if a signal waiting object M is recognized within the detection area R, the process proceeds to step ST13, and if a signal waiting object M is not recognized within the detection area R, the process returns to step ST11. Note that, in the flow process in step ST12, if the ultrasonic sensor 30 recognizes a signal waiting object M in any of the five detection areas R in total, consisting of the pedestrian ultrasonic sensors 31 arranged at the four corners of the intersection C1 and the vehicle ultrasonic sensor 32 arranged on the minor road S2 near the intersection C1, the process proceeds to step ST13.

[0039] In step ST13, lighting intervention control is executed to switch the normal lighting control of the signal lamp unit 20 based on the aspect table T2 currently being executed to lighting control based on the aspect table T1. When the step K of the aspect table T2 currently being executed corresponds to the step K1 as described above, the lighting intervention control is switched from the step K2 of the current cycle Cy to the lighting intervention control based on the aspect table T1.

[0040] If the step K of the current aspect table T2 corresponds to a step other than K1, the control switches to lighting intervention control based on the aspect table T1 from step K2 of the next cycle Cy. After the switch, the lighting control based on the aspect table T1 is executed until step K8, which completes the cycle Cy. After that, the control returns to lighting control based on the original aspect table T2 from step K1 of the cycle Cy.

[0041] With lighting control from step K4 of the aspect table T1, pedestrians waiting to cross can cross the crosswalk H at the intersection C1, and vehicles such as cars and motorcycles waiting at the traffic light can enter the main road S1 from the secondary road S2.

[0042] In step ST14, at the end of stage 5 during the lighting intervention control where the green lighting of the pedestrian signal lamp 22 ends, it is determined whether or not the signal waiting object M recognized in step ST12 continues to be recognized within the same detection area R. If the signal waiting object M is not continuously recognized, stage 8 of the lighting intervention control ends, and after returning to normal lighting control according to the aspect table T2, the process returns to step ST11 and repeats the processing executed up to that point.

[0043] If the signal waiting object M continues to be recognized over stairs 4 and 5 where the pedestrian signal lamp 22 is green and flashing based on the indication table T1 during the lighting intervention control, the process proceeds to step ST15, where the recognition of the detected object as the signal waiting object M is cancelled and it is determined to be a fixed obstacle P. A fixed obstacle P corresponds to, for example, a bicycle parked in the detection area R or a parked motorcycle.

[0044] In addition, the timing of the determination of the fixed obstacle P may be after the end of the green light of the pedestrian signal light 22 during the lighting intervention control, which is the end of step 8 of the indication table T1, other than after the lighting intervention control.

[0045] If it is determined to be a fixed obstacle P, it is excluded from the determination of the signal waiting object M so that it is not determined to be a signal waiting object M at the position determined to be a fixed obstacle P within the detection area R. Therefore, after it is determined to be a fixed obstacle P, lighting intervention control to turn on the signal lamp 20 green will not be performed due to a bicycle, motorcycle, etc. parked within the detection area R.

[0046] If it is determined in step ST15 that the obstacle is a fixed obstacle P, a subroutine shown in FIG. 5 is started, and the process returns to step ST11, and the processes of steps ST11 to ST15 are repeated.

[0047] In step ST21 of the subroutine process, it is determined whether or not the detection of the fixed obstacle P continues at the same position within the detection area R. If the detection of the fixed obstacle P continues, step ST21 is repeated.

[0048] The process of determining whether or not detection of a fixed obstacle P is continuing utilizes the fluctuation width of the time difference between ultrasonic waves transmitted and received by the ultrasonic sensor 30. If the time difference between ultrasonic waves measured continuously is included in the fluctuation width, which is a predetermined time width, it is determined that detection of a fixed obstacle P is continuing, and the process of repeating step ST21 is performed.

[0049] In step ST21, if the time difference of the measured ultrasonic waves is outside the fluctuation range, the process proceeds to step ST22, where the determination of the fixed obstacle P is cancelled, and the subroutine process ends.

[0050] This is because fixed obstacles P, such as parked bicycles and motorcycles, do not move, so the time difference between successively measured ultrasonic waves is measured to be approximately the same, and the fluctuation range is measured to be close to 0. In contrast, for example, for a pedestrian who does not cross the crosswalk H by operating a mobile device or the like, the time difference measured by ultrasonic waves fluctuates slightly due to changes in posture, etc., and is measured outside the aforementioned fluctuation range.

[0051] Therefore, by determining whether the time difference of the measured ultrasonic waves is within the fluctuation range, it is possible to determine whether the signal waiting object M that continues to be detected in the detection area R after the lighting intervention control is a fixed obstacle P or a signal waiting object M.

[0052] If a pedestrian does not cross the crosswalk H by operating a mobile terminal or the like, the subroutine processing shown in FIG. 5 is omitted, and the processing of step ST11 shown in FIG. 4 is initiated. If the pedestrian is detected again in the same position continuously for a predetermined period of time, the pedestrian is recognized as a signal waiting object M again, and the light intervention control causes the signal lamp 20 where the signal waiting object M is waiting to cross the crosswalk H to light up green, thereby enabling the pedestrian to cross the crosswalk H.

[0053] In addition, if the owner of a fixed obstacle P such as a parked bicycle or a parked motorcycle moves it, the process proceeds to step ST22, in which the determination of the fixed obstacle P is cancelled, and the process exits from the subroutine processing shown in FIG. 5.

[0054] Also, as described above, instead of the process of executing lighting control based on the aspect table T2 under normal circumstances and switching to lighting control based on the aspect table T1 during lighting intervention control, lighting control based on the aspect table T1 may be executed under normal circumstances, and lighting control may be performed during lighting intervention control to shorten the retention seconds of steps K1 and K4 in which a long retention time is set in the aspect table T1.

[0055] In this way, when the signal control system of this embodiment recognizes that the object detected in the detection area R by the ultrasonic sensor 30 is the waiting signal object M, it executes lighting intervention control to cause the signal lamp 20 where the waiting signal object M is waiting for the signal to cross the crosswalk H or enter the intersection C. Then, when the waiting signal object M continues to be recognized within the detection area R after the lighting intervention control, it determines the detected object to be a fixed obstacle P and excludes it from the objects to be detected by the ultrasonic sensor 30.

[0056] This type of processing makes it possible to prevent fixed obstacles P, such as bicycles parked within the detection area R or parked motorcycles, from being mistaken for waiting objects M, such as pedestrians waiting to cross or cars or motorcycles waiting for the light to turn on, and to prevent repeated lighting intervention control that turns the signal lamp 20 green or shortens the lighting time until the signal turns green. [Explanation of symbols]

[0057] 10, 20 Signal lights 11, 21 Vehicle signal lamps 22 Pedestrian Signal Lights 30, 31, 32 Ultrasonic sensors 40 Control section C1 Intersection M Signal waiting body P Fixed obstacle R, R1, R2 detection area

Claims

1. A signal control system including an ultrasonic sensor that detects a waiting area at an intersection, emits ultrasonic waves into the detection area, and measures reflected waves of the ultrasonic waves, and a control unit that is connected to the ultrasonic sensor and controls the lighting of a signal lamp, When a signal lamp for crossing the intersection or for entering the intersection is lit red, if an object is detected within the detection area by the ultrasonic sensor for a predetermined period of time, the control unit recognizes the object as a signal waiting object and performs lighting intervention control for the signal lamp to switch from the red lighting to a green lighting, When the green light is turned off, if the detection of the signal waiting object continues within the detection area, the object is determined to be a fixed obstacle and is excluded from the detection targets of the ultrasonic sensor. This signal control system is characterized in that, if the time difference between the ultrasonic waves continuously measured by the ultrasonic sensor after the determination is within a predetermined time range, that is, a fluctuation range, the determination that the obstacle is a fixed obstacle is continued, and if the time difference falls outside the fluctuation range based on a change in the pedestrian's posture, the determination that the obstacle is a fixed obstacle is canceled.

2. The signal control system according to claim 1, characterized in that the lighting intervention control is a lighting control for changing the signal lamp at which the signal waiting body is waiting for a signal from a constant red lighting state before the intervention to a green lighting state.

3. 3. The signal control system according to claim 1, wherein the fluctuation range is approximately equal to zero.

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