Signal information provision system and generation control method

Abstract

To provide a technology for guaranteeing safety against communication discontinuation in a mechanism that provides an automobile having a feature of autonomous driving or driving assist with information on a signal aspect at an intersection.SOLUTION: A signal information provision system 1 originates signal time information for each crossroad which includes, for each crossroad at an intersection, a change time of a signal for one cycle and a suspension aspect initiation time at which the signal changes to a suspension aspect next to the one cycle, and which does not include a change time of the signal in the future succeeding the next suspension aspect initiation time. An automobile 30 compares the change time, which is included in the received signal time information, with a current time so as to decide on an aspect of the intersection concerning a route of an own vehicle.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This invention relates to a signal information provision system, etc., that transmits signal time information related to intersections to automobiles. [Background technology]

[0002] At intersections equipped with traffic signals, traffic signal control is implemented to ensure smooth traffic flow. Traffic signal control methods are mainly classified into two types: a centralized control system (remote control system) in which the operation of traffic signals at each intersection is controlled collectively by a central device at a traffic control center, and a point-based control system in which the operation of traffic signals at each intersection is controlled independently.

[0003] In recent years, technological development of autonomous vehicles capable of self-driving has been progressing. To safely navigate intersections, autonomous vehicles need to reliably recognize the signal indications (the colors of the traffic light indicators) at those intersections. The most common method for autonomous vehicles to recognize signal indications at intersections is to directly recognize the colors of the traffic light indicators using cameras and sensors mounted on the vehicle. On the other hand, methods for autonomous vehicles to acquire information transmitted from external systems (traffic infrastructure) are also being considered (see, for example, Patent Document 1). [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-27416 [Overview of the project] [Problems that the invention aims to solve]

[0005] In the latter method described above, the transmission of signal indication information related to intersections by an external system (traffic infrastructure side) is achieved via wireless communication, as autonomous vehicles are mobile. In this case, it is assumed that the wireless communication between the external system and the autonomous vehicle will not be interrupted, but a mechanism is needed to provide a safety control (fail-safe) in the event that the wireless communication is interrupted. This issue applies not only to fully autonomous vehicles but also to vehicles with an autonomous driving level that is at the level of driver assistance. It also applies to regional and urban concepts that aim to eliminate the installation of physical traffic signals and allow only fully autonomous vehicles that rely solely on wireless communication to operate.

[0006] The problem that this invention aims to solve is to provide a technology for ensuring safety against communication interruptions in a system that provides information on signal indications related to intersections to an automobile having an autonomous driving or driver assistance function. [Means for solving the problem]

[0007] The first invention for solving the above problem is: A signal information provision system that transmits signal time information, including the time of change of signals related to an intersection, to vehicles traveling within a predetermined range including an intersection, The aforementioned automobile has a function to determine the indication of the intersection related to the vehicle's path by comparing the change time included in the signal time information with the current time. A generation means for generating signal time information for each intersecting road relating to the aforementioned intersection, which includes the signal change time for one cycle and the start time of the next stop indication change in that cycle, but does not include signal change times that are future than the start time of the next stop indication; A transmission control means for controlling the transmission of the signal time information generated by the generation means, This is a signal information provision system equipped with [specific features / features].

[0008] Other inventions include, A method for generating signal time information in a signal information provision system that transmits signal time information, including the time of change of signals related to an intersection, to vehicles traveling within a predetermined range including an intersection, The aforementioned automobile has a function to determine the indication of the intersection related to the vehicle's path by comparing the change time included in the signal time information with the current time. A first generation step for generating signal time information for each intersecting road relating to the aforementioned intersection, including the signal change time for one cycle and the start time of the next stop indication change in that cycle, but not including signal change times that are future than the start time of the next stop indication; A signal timing update detection step detects when the signal timing information update timing has arrived by detecting that the signal timing start time for all intersecting roads related to the intersection, among the signal timing changes for one cycle, has become past the current time. In response to the detection in the update timing detection step, a second generation step is performed to update the signal time information generated in the first generation step to obtain new signal time information, A generation control method including this may be configured.

[0009] According to the first invention etc., in a mechanism for providing information on signal indications related to intersections to vehicles having an automatic driving or driving support function, it is possible to ensure safety against communication interruption. That is, the signal information providing system updates and transmits signal time information including the change time of the signal related to the intersection each time the update timing arrives. The signal time information includes, for each intersecting road related to the intersection, the change time of the signal for one cycle and the stop indication start time when the stop indication changes to the next stop indication in the cycle, and does not include the change time of the signal in the future from the stop indication start time. Therefore, when communication interruption with the signal information providing system occurs and the signal time information is not received in the automobile, the automobile determines the indication of the intersection related to the route of the own vehicle based on the signal time information received previously. Therefore, after the stop indication start time when the stop indication changes to the next stop indication in the cycle included in the signal time information arrives and it is determined that it is a stop indication, the determination will continue thereafter. From this, the automobile does not enter the intersection, and safety-side control (fail-safe) against communication interruption is realized.

[0010] The second invention is as described in the above invention, The change time of the signal for one cycle includes the start time of the go-ahead indication when it changes to the go-ahead indication, The generation means has update timing detection means for detecting the arrival of the update timing of the signal time information by detecting that the start time of the go-ahead indication for each intersecting road related to the intersection, which is the start time of the go-ahead indication in the change time of the signal for one cycle, has become past the current time. A signal information providing system.

[0011] According to the second invention, the signal time information is updated at the update timing when the start time of the go-ahead indication for each intersecting road included in the signal time information has become past the current time.

[0012] The third invention is as described in the above invention, In response to the detection by the update timing detection means, the generation means: 1) when the start time of the progress indication included in the signal time information is older for the other road than for one road related to the intersection, updates the start time of the progress indication for the other road and the start time of the stop indication for the one road among the signal time information; 2) when the start time of the progress indication included in the signal time information is older for one road than for the other road, updates the start time of the progress indication for the one road and the start time of the stop indication for the other road among the signal time information. A signal information providing system.

[0013] According to the third invention, instead of updating all change times simultaneously, by alternately updating the start time of the progress indication and the start time of the stop indication for each intersecting road, the update of the signal time information that ensures safety is achieved. That is, the signal time information is updated at the update timing when the start time of the progress indication for each intersecting road is past the current time. However, at an intersection, the intersecting roads alternate between progress indications. So, for the intersecting road with a newer start time of the progress indication, since it is likely to be in a progress indication at that point, only the start time of the stop indication is updated without updating the start time of the progress indication, and the start time of the progress indication for the intersecting road with an older start time of the progress indication, that is, the intersecting road that is in a stop indication, is updated. Thus, by updating the start time of the progress indication that has already ended for each intersecting road every half cycle, it is possible to prevent misjudgment of signals in automobiles and ensure safety.

[0014] The fourth invention is in the above-mentioned invention, When the generation means updates the start time of the stop indication, it updates the next start time of the stop indication for the intersecting road related to the start time of the stop indication to be updated. A signal information providing system.

[0015] According to the fourth invention, by updating the next start time of the stop indication for the intersecting road together with the update of the start time of the stop indication included in the signal time information, the consistency of the signal time information can be ensured.

[0016] The fifth invention is, in the above invention, The aforementioned predetermined range includes multiple intersections, The generation means generates the signal time information for each intersection included in the predetermined range, The transmission control means transmits the signal time information for all of the multiple intersections included in the predetermined range. It is a signal information provision system.

[0017] According to the fifth invention, an automobile can receive not only signal time information for the next intersection in its path, but also for the intersection beyond that, which is useful for driving control. [Brief explanation of the drawing]

[0018] [Figure 1] An example of the application of a signal information provision system. [Figure 2] Example of setting control unit area. [Figure 3] Diagram illustrating signal timing information. [Figure 4] Diagram illustrating signal timing information. [Figure 5] Flowchart for the signal time information update process. [Figure 6] Diagram illustrating the update of signal time information. [Figure 7] Diagram illustrating the update of signal time information. [Figure 8] A diagram illustrating how signals are interpreted in automobiles. [Figure 9] A diagram illustrating how signals are determined in a vehicle when a communication interruption occurs. [Figure 10] A diagram illustrating how signals are determined in a vehicle when a communication interruption occurs. [Figure 11] A diagram illustrating how signals are determined in a vehicle when a communication interruption occurs. [Figure 12] Functional configuration diagram of the signal information provision system. [Modes for carrying out the invention]

[0019] Preferred embodiments of the present invention will be described below with reference to the drawings. However, the applicable forms of the present invention are not limited to the following embodiments. Furthermore, in the drawings, the same elements are denoted by the same reference numerals.

[0020] [System Configuration] Figure 1 shows an example of the application of the signal information provision system 1 in this embodiment. The signal information provision system 1 is a system that transmits signal information related to an intersection to automobiles 30 traveling within a predetermined range including an intersection.

[0021] Signal information includes signal time information. As will be described in detail later, signal time information is information based on intersection control information obtained from an external system, the traffic signal system 3, and includes information such as the signal change time (start time of indication) for each intersecting road at the intersection.

[0022] Traffic signal system 3 is a system that controls traffic (traffic flow) at intersections by controlling the signal indications of traffic lights, and centrally controls (remotely controls) the operation of traffic lights at multiple intersections. Specifically, it generates signal control commands for each intersection's traffic lights at predetermined control cycles and transmits them to each traffic light. Signal information provision system 1 acquires information including signal control commands for each intersection from traffic signal system 3 as intersection control information.

[0023] Automobile 30 has a wireless communication function to receive signal information transmitted via a wireless base station 10, and is equipped with a driving control device 32 that has a driving control function based on the received signal information as an autonomous driving or driving assistance function. In this embodiment, a planned driving route is set in advance for automobile 30, and it is described that the driving control device 32 controls the driving of the automobile (automobile 30) along this planned driving route. The driving control function of the driving control device 32 includes a function to determine the signals at intersections related to the path of the automobile (automobile 30) based on the signal time information contained in the received signal information. Furthermore, it is described that this driving control function includes known functions that realize driving control such as collision prevention and maintaining a safe distance by image recognition of other vehicles based on images captured by an onboard camera, etc. Furthermore, this driving control function may also include a function to directly image recognize the color of the indicator lights of traffic signals using an onboard camera, etc., as in the conventional method.

[0024] The signal information provision system 1 transmits signal information relating to intersections within a control unit area 20 to vehicles 30 traveling within that control unit area 20, via a wireless base station 10 installed so that the entire control unit area 20 is within its communication range. The signal information provision system 1 also repeatedly generates and transmits signal information at predetermined intervals. This transmission can be done in the form of a broadcast without specifying the recipient. The signal information includes information specific to each intersection (for example, signal time information). Each piece of information is associated with the identification information (intersection ID) of the corresponding intersection.

[0025] Figure 2 is a diagram illustrating the control unit area 20. In Figure 2, the solid lines in the top, bottom, left, and right directions represent roads, and intersections are indicated by four dots representing traffic signals. Each dashed circular area also represents a control unit area 20. As shown in Figure 2, multiple control unit areas 20 are set up, and adjacent areas 20 are set up to partially overlap. When a vehicle 30 is located in an overlapping area of ​​the control unit areas 20, it can acquire signal information for each overlapping control unit area 20. Therefore, a vehicle 30 traveling on a road can acquire signal information for each adjacent intersection without interruption, unless a malfunction or other problem occurs.

[0026] [Signal time information] Signal timing information is information based on intersection control information obtained from the traffic signal system 3. Figure 3 is a diagram illustrating signal timing information. Figure 3 shows an example of signal timing information for a four-way intersection where a main road and a secondary road intersect. Signal timing information is generated based on signal cycle information, which is information about the signal cycle of the intersection. Signal cycle information includes signal indication tier table, cycle length, split, and offset, which are signal control parameters. Signal control parameters are controlled by signal control commands from the traffic signal system 3 included in the intersection control information.

[0027] The signal timing information includes, for each intersecting road at the intersection, the signal change time for one cycle and the start time of the next stop indication change within that cycle. In the example in Figure 3, the signal timing information includes, for each main road and secondary road that are intersecting roads, the "red light start time," which is the start time of the stop indication change to a stop indication (red light), the "green light start time," which is the start time of the proceed indication change to a proceed indication (green light), and the "next red light start time," which is the start time of the next stop indication change within that cycle.

[0028] Also, since the "next red signal start time" in the signal time information is the start time of the red signal in the next cycle, it is a future time compared to the "red signal start time" and "blue signal start time", which are the signal change times for that one cycle.

[0029] FIG. 4 is an example of signal time information. In FIG. 4, on the upper side, as the common horizontal time, the times (start times) at which the signals (the "blue signal" which is a go indication, the "red signal" which is a stop indication, and the "yellow signal") of the main road and the secondary road for a plurality of cycles obtained from the signal cycle information change are shown, and on the lower side, the signal time information at a certain time T0 is shown. Note that the cycle starts from the start of the blue signal on the main road.

[0030] In the example of FIG. 4, in the signal time information at time T0, the signal change times of the main road are the start time t of the red signal in the second cycle a4 and the start time t of the blue signal a1 which are the "red signal start time" and the "blue signal start time" respectively, and the start time t of the red signal in the third cycle, which is the cycle next to the start time t of the red signal in the second cycle <00000*03>is the "next red signal start time". Also, the signal change times of the secondary road are the start time t of the red signal in the first cycle a4 and the start time t of the blue signal in the second cycle b0 which are the "red signal start time" and the "blue signal start time" respectively, and the start time t of the red signal in the second cycle, which is the cycle next to the start time t of the red signal in the first cycle b1 is the "next red signal start time". Note that the period from the start time t of the red signal on the secondary road b0 to the next red signal start time t b2 spans the first and second cycle numbers, which are the ordinal numbers of the cycles starting from the start of the blue signal on the main road, but the length of the period corresponds to one cycle. b0 From the start time t of the red signal on the secondary road to the next red signal start time t b2 Although the period up to spans the first and second cycle numbers, which are the ordinal numbers of the cycles starting from the start of the blue signal on the main road, the length of the period corresponds to one cycle.

[0031] The signal information provision system 1 updates signal time information as time progresses. Figure 5 is a flowchart illustrating the process of updating signal time information for a given intersection (signal time information update process).

[0032] As shown in Figure 5, the signal information provision system 1 determines whether the green light start times for all intersecting roads related to the intersection, among the signal change times for one cycle included in the current signal time information, have all become past the current time. If not all have become past the current time, it waits (Step S1: NO). If all have become past the current time (Step S1: YES), it determines that it is time to update the signal time information. Upon determining that it is time to update, the signal time information is updated.

[0033] Specifically, if the green light start time for the main road (one road) included in the signal time information is older than the green light start time for the secondary road (the other road) (Step S3: YES), the green light start time for the main road (one road) in the signal time information is updated (Step S5). Also, the red light start time and the next red light start time for the secondary road (the other road) in the signal time information are updated (Step S7).

[0034] On the other hand, if the green light start time for the secondary road (other road) included in the signal time information is older than the green light start time for the main road (one road) (step S9: YES), the green light start time for the secondary road (other road) in the signal time information is updated (step S11). Also, the red light start time and the next red light start time for the main road (one road) in the signal time information are updated (step S13). After performing the above processing, the process returns to step S1 and the same process is repeated.

[0035] Figures 6 and 7 show an example of updating signal time information according to the signal time information update process described above. Figure 6 shows the case where approximately half a cycle has elapsed from time T0 in Figure 4 to time T1. At time T1, the green light start time t for the main road is a1 and the start time of the green light for the secondary road t b1Both are past times (older than time T1), and the update timing has arrived (corresponding to step S1: YES in Figure 5). And the green light start time t for the main road a1 The green light start time for the secondary road is t b1 Because it is older (corresponding to step S3: YES in Figure 5), the start time of the green light on the main road and the start time of the red light and the next red light on the secondary road are updated (corresponding to steps S5 and S7 in Figure 5). That is, the “start time of the green light” on the main road is updated to the start time of the green light in the 3rd cycle. a3 The "start time of the red light" on the secondary road has been updated to the start time of the red light for the second cycle. b2 It has been updated, and the “next red light start time” is the start time of the third red light cycle. b4 It will be updated.

[0036] Figure 7 shows the case where approximately half a cycle has passed since time T1 in Figure 6, resulting in time T2. At time T2, the green light start time for the main road is t a3 and the start time of the green light on the secondary road tb1 Both are past times (older than time T2), and the update timing has arrived (corresponding to step S1: YES in Figure 5). And the green light start time t of the secondary road b1 The green light start time for the main road is t a3 Because it is older (corresponding to step S9: YES in Figure 5), the start time of the green light on the secondary road and the start time of the red light and the next red light on the main road are updated (corresponding to steps S11 and S13 in Figure 5). That is, the “start time of the green light” on the secondary road is updated to the start time of the green light in the 3rd cycle. b3 The "red light start time" for the main road has been updated to the start time of the third cycle of the red light. a4 It has been updated, and the “next red light start time” is the start time of the 4th cycle of red lights. a6 It will be updated.

[0037] In this way, the signal time information is updated alternately every half cycle: (1) the older of the two green light start times for the main road and the secondary road is updated, and (2) the older of the two red light start times for the main road and the secondary road is updated, and the next red light start time for the same road is also updated along with the update of the red light start time.

[0038] The driving control device 32 installed in the vehicle 30 has a function to determine the indication of the intersection related to the vehicle's (vehicle 30's) path by comparing the change time included in the received signal time information with the current time. Figure 8 is a diagram illustrating the determination of the intersection indication by the driving control device 32. Figure 8 shows a case where vehicle 30 traveling on the main road approaches a four-way intersection where a main road and a secondary road intersect. In this case, the driving control device 32 installed in vehicle 30 determines the indication of the intersection related to the vehicle's path by comparing the change time of the signal related to the main road in the signal time information with the current time.

[0039] Specifically, the center of Figure 8 shows an example of the latest signal time information received by the driving control device 32, and the lower part shows the signal changes related to the main road indicated by this signal time information. Note that the signal time information does not include the start time of the yellow light, so the driving control device 32 determines the start time of the yellow light to be a predetermined time (for example, 3 seconds) prior to the “start time of the red light” and the “start time of the next red light” in the signal time information.

[0040] Furthermore, if the green light start time and red light start time in the received signal time information are both in the past compared to the current time, and the green light start time is older than the red light start time, the driving control device 32 invalidates the green light start time, and also invalidates the yellow light start time determined by working backward from the red light start time. This ensures that even if the green light start time is in the past compared to the current time, the system will not mistakenly determine that the signal is green in the event of a communication interruption with the signal information provision system 1, thereby achieving further safety (fail-safe) control.

[0041] The driving control device 32 determines the current signal to be the signal that started at a time in the past that is closest to the current time (the most recent past time) among the signal change times related to the road on which the vehicle (automobile 30) is traveling. In the example in Figure 8, the current time is time T. a Therefore, the most recent past change time is the "start time of the red light," so the current signal is judged to be "red light (stop indication)." Also, the current time is time T. b Therefore, since the most recent past change time is the "start time of the green light," the current signal is judged to be a "green light (proceed indication)."

[0042] [g disconnection] As described above, the signal information provision system 1 updates the signal time information it transmits at update timings that occur approximately every half cycle, and the driving control device 32 installed in the vehicle 30 determines the signal related to the vehicle's (vehicle 30's) path based on the latest received signal time information. However, if communication with the signal information provision system 1 is interrupted, the driving control device 32 will not receive the signal time information (more precisely, the signal information including the signal time information). This communication interruption with the signal information provision system 1 can occur, for example, due to a malfunction in the wireless communication function of the vehicle (vehicle 30), a malfunction in the signal information provision system 1, or a malfunction in the communication network N2 or wireless base station 10 between the signal information provision system 1 and the driving control device 32.

[0043] Figure 9 illustrates an example of signal determination by the driving control device 32 in the event of a communication interruption with the signal information provision system 1. Similar to Figure 8, Figure 9 shows a case where a vehicle 30 traveling on the main road approaches a cross intersection where the main road and a secondary road intersect. The upper part of Figure 9 shows an example of signal time information, and the lower part shows the signal change determined by the driving control device 32 installed in the vehicle 30.

[0044] In this case, the driving control device 32 determines the signal related to the vehicle's (the vehicle 30's) path based on the signal change time for the main road included in the signal time information. If, for example, a communication interruption occurs with the signal information provision system 1 between the "red light start time (10:00:35)" and the "green light start time (10:01:03)", then the driving control device 32 will no longer receive signal time information from that point onward.

[0045] The driving control device 32 determines that the signal is red at the time the communication is interrupted. Subsequently, as time passes and the green light start time (10:01:03) arrives, it determines that the signal has changed to green. Then, when the yellow light start time (10:01:32) arrives, it determines that the signal has changed to yellow. Furthermore, when the next red light start time (10:01:35) arrives, it determines that the signal has changed to red. Since the signal time information does not include the signal change times for times after that, it continues to determine that the signal is red thereafter. Thus, when a communication is interrupted, the driving control device 32 continues to determine that the signal is red from the next red light start time onward, which is included in the signal time information at that time.

[0046] If communication with the signal information provision system 1 is successful, the "green light start time" for the main road in the signal time information will be updated after the "next red light start time (10:01:35)" has elapsed, which follows the "green light start time (10:00:38)" for the secondary road (corresponding to steps S3:YES~S5 in Figure 5).

[0047] The driving control device 32 compares the time of the signal change (start time) at the intersection, determined based on the signal time information, with the estimated arrival time of the vehicle (automobile 30) at the intersection, and performs control including a decision on whether or not to enter the intersection. If communication with the signal information provision system 1 is lost and it becomes after the start time of the next red light (10:01:35 in Figure 9), the driving control device 32 will determine that the light is red and will prevent the vehicle (automobile 30) from entering the intersection, stopping it before it. Even if the light is actually green, the vehicle (automobile 30) will stop before entering the intersection.

[0048] The signal information provision system 1 transmits signal time information (signal information) for each of the multiple intersections within the control unit area 20. Therefore, the driving control device 32 can grasp the signal change times for each of the multiple intersections (to be entered) related to the vehicle's (automobile 30's) path within the control unit area 20. Consequently, if communication with the signal information provision system 1 is lost, the driving control device 32 will control the vehicle's movement based on the signal time information for each intersection received up to that point. For each intersection, the driving control device 32 will compare the start time of the next red light with the estimated arrival time of the vehicle (automobile 30) to determine whether or not to enter that intersection.

[0049] For example, in Figure 10, suppose the planned route of car 30a is to go straight through intersections 5a, 5b, and 5c, which are all located within the same control unit area 20, and car 30a is approaching intersection 5a. Now, consider a case where the driving control device 32 installed in car 30a experiences a communication interruption with the signal information provision system 1 due to a malfunction in the device. Based on the last signal time information (signal information) received before the communication interruption, the driving control device 32 will control the driving of the vehicle (car 30a). For example, for intersection 5a and the next intersection 5b, the vehicle can enter and pass through them because it will arrive before the next red light start time, but for the next intersection 5c, it will arrive after the next red light start time, so it will not be able to enter and will stop before it. This is a safe driving control measure.

[0050] If communication with the signal information provision system 1 is functioning correctly, other vehicles 30 can receive signal information (signal time information) transmitted as it is transmitted. Based on the latest signal information, they can determine the time of the next green light and control their entry into the intersection.

[0051] Figure 11 shows an example of a situation where a communication interruption occurs between the signal information provision system 1 and the driving control device 32 installed in a vehicle 30 approaching a cross-shaped intersection due to a malfunction in the signal information provision system 1. In Figure 11, with the lateral direction as a common time, the changes in signals that the driving control device 32 installed in the vehicle 30 traveling on the main road and secondary road of the intersection determines as signals related to the vehicle's path are shown divided into upper, middle, and lower sections.

[0052] In the example in Figure 11, a communication interruption occurs at "10:00:43", after the green light start time "10:00:38" on the secondary road has passed and the signal time information has been updated. From this time onward, all vehicles 30 will not receive signal time information. Consequently, vehicle 30 traveling on the main road will continue to judge that the light is red from the next red light start time "10:01:35" onward, and vehicle 30 traveling on the secondary road will continue to judge that the light is red from the next red light start time "10:01:00" onward. When communication is restored at the following time "10:01:50", all vehicles 30 will receive signal time information, and based on this received signal time information, vehicle 30 traveling on the secondary road will judge that the light is green because the green light start time has passed.

[0053] [Functional Configuration] Figure 12 shows an example of the functional configuration of the signal information provision system 1. According to Figure 12, the signal information provision system 1 comprises an operation unit 102, a display unit 104, an audio output unit 106, a communication unit 108, a processing unit 200, and a storage unit 300 as functional units, and is configured as a type of computer system.

[0054] The operation unit 102 is implemented by an input device such as a button switch, touch panel, or keyboard, and outputs an operation signal to the processing unit 200 according to the operation performed. The display unit 104 is implemented by a display device such as an LCD (Liquid Crystal Display) or touch panel, and displays various information according to the display signal from the processing unit 200. The sound output unit 106 is implemented by a speaker and outputs sound based on audio signals such as notification sounds input from the processing unit 200. The communication unit 108 is implemented by a wired or wireless communication device and communicates with external devices such as the traffic signal system 3 via the communication network N1, and also performs wireless communication with external devices such as the driving control device 32 mounted on the automobile 30 via the wireless base station 10 connected to the communication network N2.

[0055] The processing unit 200 is implemented by an arithmetic unit such as a CPU (Central Processing Unit), and based on programs and data stored in the storage unit 300, it issues instructions and transfers data to each part that constitutes the signal information provision system 1, thereby controlling the entire signal information provision system 1. In addition, the processing unit 200 has a generation unit 202, a transmission control unit 206, and a clock unit 210 as functional units according to this embodiment. However, these functional units can also be configured as independent arithmetic circuits using ASICs (Application Specific Integrated Circuits) or FPGAs (Field Programmable Gate Arrays), etc.

[0056] The generation unit 202 generates signal time information for each intersecting road at an intersection, including the signal change time for one cycle and the start time of the next stop indication change in that cycle, but excluding signal change times that are future than the start time of the next stop indication (see Figures 3 and 4).

[0057] Furthermore, the generation unit 202 includes an update timing detection unit 204. The signal change time for one cycle includes the start time of the change to a proceed indication, and the update timing detection unit 204 detects when the start time of the proceed indication for all intersecting roads related to the intersection, which is part of the signal change time for one cycle, has become past the current time, thereby detecting the arrival of the timing for updating the signal time information.

[0058] In response to the detection by the update timing detection unit 204, the generation unit 202 updates the signal time information, specifically the signal time information, for the start of the proceed indication for the other road and the signal time information for the one road if the start of the proceed indication included in the signal time information is older for the one road at the intersection, and updates the signal time information, specifically the start of the proceed indication for the one road and the signal time information for the other road if the start of the proceed indication included in the signal time information is older for the one road at the intersection.

[0059] Furthermore, when the generation unit 202 updates the start time of a stop signal, it updates the next start time of a stop signal for the intersecting road related to the start time of the stop signal being updated. In addition, the generation unit 202 generates signal time information for each intersection included in a predetermined range.

[0060] Specifically, the generation unit 202 generates signal time information for each intersection based on the signal cycle information (see Figures 3 and 4). It also updates the signal time information in accordance with the update timing detection by the update timing detection unit 204. In other words, if the green light start time for the main road (one road) included in the current signal time information is older than the green light start time for the secondary road (the other road), the green light start time for the main road (one road), and the red light start time and next red light start time for the secondary road (the other road) in the signal time information are updated. If the green light start time for the secondary road (the other road) is older than the green light start time for the main road (one road), the green light start time for the secondary road (the other road), and the red light start time and next red light start time for the main road (one road) in the signal time information are updated (see Figures 5 to 7).

[0061] The update timing detection unit 204 determines that it is time to update the signal time information if the green light start times for all intersecting roads included in one cycle of the signal time information are in the past time (see Figure 5).

[0062] The signal cycle information for an intersection is stored in the intersection management information 320. The intersection management information 320 is generated for each intersection and stores the signal cycle information, the latest signal time information generated by the generation unit 202, and the signal information transmitted so far by the transmission control unit 206, associated with the intersection ID, which is the identification information of the corresponding intersection. The signal cycle information includes the indication stage table and signal control parameters controlled by signal control commands from the traffic signal system 3.

[0063] The transmission control unit 206 controls the transmission of signal time information generated by the generation unit 202. The transmission control unit 206 also transmits signal time information for all multiple intersections included within a predetermined range.

[0064] Specifically, the transmission control unit 206 generates signal information for each intersection, including signal time information generated by the generation unit 202, and for each control unit area 20 which is a predetermined range, it repeatedly performs the process of transmitting the signal information for each intersection within the control unit area 20 to the automobiles 30 within the control unit area 20 via the wireless base station 10 installed in the control unit area 20 at predetermined intervals.

[0065] The control unit area 20 is set according to the control unit area setting information 310. The control unit area setting information 310 is generated for each control unit area which is a predetermined range, and stores the intersection ID of the intersection within the area and the base station ID of the wireless base station 10, associated with the area ID which is the identification information of the control unit area.

[0066] The clock unit 210 is configured with an oscillation circuit having a crystal oscillator and measures the current time and the elapsed time from a specified timing. It is preferable to adopt a method of obtaining more accurate time information via a communication device and periodically or as needed correcting the current time being measured. Methods for obtaining time information include NTP servers, GNSS (Global Navigation Satellite System), and radio-controlled clocks.

[0067] The memory unit 300 is implemented using a storage device such as a hard disk, ROM (Read Only Memory), or RAM (Random Access Memory), and stores programs and data for the processing unit 200 to comprehensively control the signal information provision system 1. The memory unit 300 is also used as a workspace for the processing unit 200, and temporarily stores calculation results executed by the processing unit 200 according to various programs, as well as input data via the operation unit 102 and the communication unit 108. In this embodiment, the memory unit 300 stores the signal information provision program 302, control unit area setting information 310, and intersection management information 320.

[0068] The signal information provision program 302, when executed by the processing unit 200, realizes the function of transmitting signal control information related to the intersection to vehicles traveling within a predetermined range, including the intersection.

[0069] [Effects and Effects] According to this embodiment, in a system that provides traffic signal indication information related to intersections to vehicles with autonomous driving or driver assistance functions, it is possible to ensure safety against communication interruptions. Specifically, the traffic signal information provision system 1 updates and transmits traffic signal time information, including the time of change of traffic signals related to intersections, each time an update timing arrives. This traffic signal time information includes the time of change of traffic signals for one cycle and the start time of the stop indication change to the next stop indication for each intersecting road at the intersection, but does not include traffic signal change times in the future from the start time of the stop indication. Therefore, if a communication interruption occurs with the traffic signal information provision system 1 and the vehicle 30 stops receiving traffic signal time information, the vehicle 30 will determine the indication of the intersection related to its path based on the traffic signal time information received up to that point. Consequently, once the vehicle determines that the indication is a stop indication after the start time of the stop indication change to the next stop indication included in the traffic signal time information has arrived, it will continue to make that determination thereafter. As a result, the vehicle 30 will not enter the intersection, and a safe control (fail-safe) against communication interruptions is achieved.

[0070] [Differentiation] It should be noted that the applicable embodiments of the present invention are not limited to those described above, and can be modified as appropriate without departing from the spirit of the invention.

[0071] (A) Signal time information The signal time information transmitted by the signal information provision system 1 may include the start times of other signals corresponding to the type of intersection, such as yellow lights and green lights for right turns.

[0072] (B) Intersection In the above embodiment, a four-way intersection where a main road and a secondary road intersect was used as an example of an intersection where two intersecting roads meet, but the same applies to a T-junction. Furthermore, it is similarly applicable to intersections where two or more intersecting roads meet. In this case, the signal time information update should be performed by detecting the arrival of the update timing when the green light start times for all intersecting roads for one cycle have become past the current time, updating the oldest green light start time, and updating the red light start time and the next red light start time for the intersecting road corresponding to the next oldest green light start time. [Explanation of symbols]

[0073] 1…Signal information provision system 200... Processing Unit 202...Generation section 204...Update timing detection unit 206... Transmission Control Unit 210... Clock Department 300...Storage section 302…Signal Information Provision Program 310... Control unit area setting information 320… Intersection Management Information 10… Wireless base stations 20... Control unit area 30…Automobile 32... Driving control device 3…Traffic signal system 5a,5b,5c...intersection N1,N2…Communication network

Claims

1. A signal information provision system that transmits signal time information, including the time of change of signals related to an intersection, to vehicles traveling within a predetermined range including an intersection, The aforementioned automobile has a function to determine the indication of the intersection related to the vehicle's path by comparing the change time included in the signal time information with the current time. A generation means for generating signal time information for each intersecting road relating to the aforementioned intersection, which includes the signal change time for one cycle and the start time of the next stop indication change in that cycle, but does not include signal change times that are future than the start time of the next stop indication. A transmission control means for controlling the transmission of the signal time information generated by the generation means, A signal information provision system equipped with the following features.

2. The signal change time for one cycle includes the start time of the change to a progress indication. The generation means includes an update timing detection means that detects when the timing for updating the signal time information has arrived by detecting that the start time of the proceed indication among the signal change times for one cycle, and that the start time of the proceed indication for all intersecting roads related to the intersection has become past the current time. The signal information provision system according to claim 1.

3. The generation means, in response to the detection by the update timing detection means, 1) updates the start time of the proceed indication for the other road and the start time of the stop indication for the one road in the signal time information if the start time of the proceed indication included in the signal time information is older for the one road than for the one road relating to the intersection, and 2) updates the start time of the proceed indication for the one road and the start time of the stop indication for the other road in the signal time information if the start time of the proceed indication included in the signal time information is older for the one road than for the other road. The signal information provision system according to claim 2.

4. When updating the stop signal start time, the generating means updates the next stop signal start time for the intersecting road related to the stop signal start time to be updated. The signal information provision system according to claim 2 or 3.

5. The aforementioned predetermined range includes multiple intersections, The generation means generates the signal time information for each intersection included in the predetermined range, The transmission control means transmits the signal time information for all of the multiple intersections included in the predetermined range. A signal information provision system according to any one of claims 1 to 3.

6. A method for generating signal time information in a signal information provision system that transmits signal time information, including the time of change of signals related to an intersection, to vehicles traveling within a predetermined range including an intersection, The aforementioned automobile has a function to determine the indication of the intersection related to the vehicle's path by comparing the change time included in the signal time information with the current time. A first generation step for generating signal time information for each intersecting road relating to the aforementioned intersection, including the signal change time for one cycle and the start time of the next stop indication change in that cycle, but not including signal change times that are future than the start time of the next stop indication; A signal timing update detection step detects when the signal timing information update timing has arrived by detecting that the signal timing start time for all intersecting roads related to the intersection, among the signal timing changes for one cycle, has become past the current time. In response to the detection of the update timing step, a second generation step is performed to update the signal time information generated in the first generation step to obtain new signal time information, A generation control method including the following.

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