Progress stop determination device

Abstract

The forward stop determination device includes a camera mounted on an autonomous vehicle and acquiring image information of a forward direction of the vehicle, a signal recognition unit recognizing a signal in the forward direction of the vehicle based on the image information acquired by the camera at a predetermined cycle and recognizing a lighting state of the recognized signal, a speed acquisition unit acquiring speed information of the vehicle, a position acquisition unit acquiring position information of the vehicle relative to a stop position corresponding to the signal recognized by the signal recognition unit, and a forward stop determination unit determining whether the vehicle should proceed or stop based on the lighting state of the signal recognized by the signal recognition unit, the speed information acquired by the speed acquisition unit, and the position information acquired by the position acquisition unit at a predetermined cycle when the signal is recognized by the signal recognition unit. The forward stop determination unit also determines whether the vehicle should proceed or stop based on a last determination result and the lighting state of the signal recognized last by the signal recognition unit.

Description

Technical Field

[0001] This invention relates to a forward / stop determination device for determining whether an autonomous vehicle should move forward or stop. Background Technology

[0002] As such a device, there are known devices that determine the permitted direction of vehicle travel by determining the illumination state of a traffic signal (see, for example, Patent Document 1). The device described in Patent Document 1, when it is impossible to determine the illumination state of a traffic signal based on an image captured by a traffic signal installed at an intersection in the direction of vehicle travel, estimates the illumination state of the traffic signal based on past images obtained before the time the image was captured, determines the permitted direction of vehicle travel at the intersection based on the estimation result, and performs vehicle driving control based on the determination result.

[0003] By popularizing autonomous vehicles capable of operating on regular roads with traffic signals, the safety and convenience of the entire transportation society can be improved, leading to a sustainable transportation system. Furthermore, by increasing the efficiency and smoothness of transportation, CO2 emissions can be reduced, lessening the environmental impact.

[0004] However, as described in Patent Document 1, relying solely on the illumination state of the signal sometimes makes it difficult to reliably determine whether the vehicle should move forward or stop, and sometimes makes it difficult to effectively control the vehicle's movement.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent document 1: Japanese Patent Application Publication No. 2020-67703 (JP2020-067703A). Summary of the Invention

[0008] The present invention provides a forward / stop determination device comprising: a camera mounted on an autonomous vehicle to acquire image information of the vehicle's forward direction; a signal recognition unit that, based on the image information acquired by the camera, identifies traffic signals in the forward direction of the autonomous vehicle at predetermined intervals and identifies the illumination state of the identified traffic signals; a speed acquisition unit that acquires speed information of the autonomous vehicle; a position acquisition unit that acquires position information of the autonomous vehicle relative to a stopping position corresponding to a traffic signal identified by the signal recognition unit; and a forward / stop determination unit that, when a traffic signal is identified by the signal recognition unit, determines at predetermined intervals whether the autonomous vehicle should move forward or stop based on the illumination state of the traffic signal identified by the signal recognition unit, the speed information acquired by the speed acquisition unit, and the position information acquired by the position acquisition unit. The forward / stop determination unit further determines whether the autonomous vehicle should move forward or stop based on the previous determination result and the illumination state of the traffic signal previously identified by the signal recognition unit. Attached Figure Description

[0009] The objectives, features, and advantages of the present invention are further illustrated by the following description of embodiments in conjunction with the accompanying drawings.

[0010] Figure 1A This is a diagram used to illustrate situations where a vehicle should stop.

[0011] Figure 1B It is a diagram used to illustrate the situation in which a vehicle should move forward.

[0012] Figure 2 It is a diagram used to illustrate the position and speed of vehicles near the signal.

[0013] Figure 3 This is a block diagram that schematically illustrates an example of the main structural components of a forward stop determination device according to an embodiment of the present invention.

[0014] Figure 4 This diagram illustrates the processing of the forward stop determination device according to an embodiment of the present invention.

[0015] Figure 5 It is used for explanation Figure 3 The diagram shows the forward stop determination result of the forward stop determination unit. Detailed Implementation

[0016] The following is for reference Figures 1A to 5 The embodiments of the present invention are described below. The forward / stop determination device of the present invention is applied to an autonomous vehicle having a driving control device that controls the driving actuator to enable the vehicle to drive automatically, and performs forward / stop determination of the autonomous vehicle on a general road equipped with traffic signals.

[0017] Figure 1A and Figure 1B This is a diagram used to illustrate when a vehicle should stop at a traffic signal and when it should proceed. For example... Figure 1A and Figure 1B As shown, when the traffic signal in front of the vehicle is illuminated as a green signal (G) indicating that the vehicle is allowed to proceed, the vehicle can proceed directly according to the surrounding traffic conditions (times t1 and t5). However, when the traffic signal is illuminated as a red signal (R) indicating that the vehicle is prohibited from proceeding, the vehicle must stop at the stop position (stop line) unless it has already crossed the stop line corresponding to that signal (times t3–t4 and t7–t8).

[0018] On the other hand, when the signal is illuminated as a yellow signal Y, prohibiting vehicles from crossing the stop position except in cases where it is not safe to stop, it is necessary to determine whether the vehicle should stop at the stop position or proceed directly based on the vehicle's position and speed relative to the stop position at that time.

[0019] Figure 2 This is a diagram used to illustrate the position and speed of vehicles near a traffic signal. Figure 2 In the diagram, area A corresponds to the positions of vehicles that have already passed the stop position, while areas B through E correspond to the positions of vehicles approaching the stop position. Areas B and C correspond to the positions and speeds of vehicles that can decelerate and stop at the stop position, while areas D and E correspond to the positions and speeds of vehicles that cannot decelerate and stop safely at the stop position. Areas C and D correspond to the positions and speeds of vehicles that would pass the stop position before the red signal R appears if they continue driving at the same speed. Areas B and E correspond to the positions and speeds of vehicles that would pass the stop position after the red signal R appears if they continue driving at the same speed.

[0020] For example, such as Figure 1A As shown, at time t2, when the vehicle's position and speed correspond to region B (which is now yellow signal Y), if the vehicle continues driving at the same speed, it will cross the stop position after the signal turns red signal R at time t3. In this case, it can be determined that the vehicle should have stopped at the stop position at time t2.

[0021] On the other hand, such as Figure 1B As shown, given the vehicle's position and speed within region D at time t6 (when the signal turns yellow, Y), maintaining the vehicle speed and continuing forward will allow it to pass the stopping position before time t7 (when the signal turns red, R). In this case, it can be determined that the vehicle should continue forward at time t6 instead of stopping at the stopping position.

[0022] Autonomous vehicles control driving actuators via a driving control device based on the forward / stop determination result and surrounding traffic conditions; therefore, stable forward / stop determination is required. Furthermore, forward / stop determination is performed periodically, for example, based on the shooting cycle of a camera detecting the illumination status of a signal. However, even when the signal illumination status cannot be temporarily identified due to obstructions, weather, or other factors, stable forward / stop determination is still necessary. Therefore, this embodiment is configured as a forward / stop determination device to reliably determine whether the autonomous vehicle should move forward or stop.

[0023] Figure 3 This is a block diagram schematically illustrating an example of the main structural components of a forward / stop determination device (hereinafter referred to as the device) 100 according to an embodiment of the present invention. Figure 3 As shown, the device 100 is mainly composed of an electronic control unit (ECU) 10. The ECU 10 is a computer consisting of an arithmetic unit 11 such as a CPU (central processing unit), a storage unit 12 such as ROM (read-only memory) and RAM (random access memory), and other peripheral circuits.

[0024] ECU 10 is configured, for example, as part of a group of multiple ECUs mounted on a vehicle and controlling the vehicle's actions. ECU 10 may also include a computer located outside the vehicle, or it may be a combination of a computer mounted on the vehicle and a computer located outside the vehicle. ECU 10 is connected to a camera 1, a speed acquisition unit 2, a position acquisition unit 3, and a driving control device 200 mounted on an autonomous driving vehicle.

[0025] Camera 1 is configured with imaging elements such as CCD (charge-coupled device) and CMOS (complementary metal-oxide-semiconductor), and is set to capture images of the entire forward direction, including the traffic signals set on the road where the autonomous vehicle is traveling, and acquire image information of the forward direction at predetermined intervals. Speed ​​acquisition unit 2 is configured, for example, with wheel speed sensors, and acquires information about the speed of the autonomous vehicle (speed information). Position acquisition unit 3 is configured, for example, with a positioning sensor that receives positioning signals transmitted from positioning satellites, and acquires information about the relative vehicle position (position information) of the autonomous vehicle with respect to the stopping positions corresponding to each traffic signal by measuring the current position of the autonomous vehicle.

[0026] The arithmetic unit 11 of the ECU 10 includes a signal recognition unit 13 and a forward / stop determination unit 14 as a functional structure. That is, the arithmetic unit 11 of the ECU 10 functions as both the signal recognition unit 13 and the forward / stop determination unit 14. The storage unit 12 stores various control programs, thresholds used in the programs, and other information.

[0027] Figure 4This diagram illustrates the processing of the arithmetic unit 11, showing the processing flow of the signal recognition unit 13 and the forward / stop determination unit 14. (As shown...) Figure 4 As shown, the signal recognition unit 13 identifies traffic lights in the forward direction of the autonomous vehicle at a predetermined period based on image information from the camera 1, and identifies the illumination state of the identified traffic lights. More specifically, the illumination state of the traffic lights is identified as any one of the following: green signal G, yellow signal Y, red signal R, and an undefined state U that is unclear as to which of the three signals.

[0028] When a traffic signal is identified by the signal recognition unit 13, the forward stop determination unit 14 performs a forward stop determination based on the illuminated state of the identified traffic signal, the speed information obtained by the speed acquisition unit 2, the position information obtained by the position acquisition unit 3, and the previous forward stop determination result. More specifically, it determines the forward stop based on the illuminated state of the traffic signal in the previous and current tests, and the corresponding information about the vehicle speed and position. Figure 2 The forward stop determination is performed in areas A to E based on the previous forward stop determination result. When the forward stop determination unit 14 performs the forward stop determination, the driving control device controls the driving actuator based on the forward stop determination result and the surrounding traffic conditions.

[0029] Figure 5 This is a diagram used to illustrate the forward stop determination result of the forward stop determination unit 14. (Example) Figure 5 As shown, when the signal recognition unit 13 recognizes the green signal G, regardless of the previous signal light status, the area A to E corresponding to the vehicle speed and vehicle position, or the previous forward / stop determination result, it is determined to be "Go".

[0030] When the signal recognition unit 13 previously identified a green signal G and the forward / stop determination unit 14 determined it to be "Go", and this time a yellow signal Y or an unknown state U is identified, it is determined to be "Go" in the case of areas A, C, and D, and "Stop" in the case of areas B and E.

[0031] In regions A, C, and D, if the signal recognition unit 13 previously identified a yellow signal Y and the forward / stop determination unit 14 determined it to be "Go", and the yellow signal Y is identified again this time, it is determined to be "Go". In regions B and E, if the signal recognition unit 13 previously identified a yellow signal Y and the forward / stop determination unit 14 determined it to be "Stop", and the yellow signal Y is identified again this time, it is determined to be "Stop".

[0032] In area A, if the signal recognition unit 13 previously identified a yellow signal Y, a red signal R, or an unidentified state U, and the forward / stop determination unit 14 determined it to be "Go", and this time a red signal R or an unidentified state U is identified, it is determined to be "Go". In areas B and E, if the signal recognition unit 13 previously identified a yellow signal Y, a red signal R, or an unidentified state U, and the forward / stop determination unit 14 determined it to be "Stop", and this time a red signal R or an unidentified state U is identified, it is determined to be "Stop".

[0033] On the other hand, when the signal recognition unit 13 previously identified an unknown state U and this time identifies a yellow signal Y or another unknown state U, regardless of regions A to E, it maintains the previous forward / stop determination result and directly uses it as the current forward / stop determination result. In cases where the signal was not previously identified but a yellow signal Y is identified this time, the determination may alternate between forward and stop depending on factors such as vehicle speed, leading to unnecessary deceleration and instability in driving control based on forward / stop determination. In such situations, maintaining the previous forward / stop determination result ensures the stability of the forward / stop determination result and reliably suppresses unnecessary deceleration in driving control.

[0034] The following effects can be achieved by adopting this implementation method.

[0035] (1) The device 100 includes: a camera 1 mounted on an autonomous vehicle to acquire image information of the autonomous vehicle's forward direction; a signal recognition unit 13 that, based on the image information acquired by the camera 1, identifies a signal in the forward direction of the autonomous vehicle at a predetermined period and identifies the illumination state of the identified signal; a speed acquisition unit 2 that acquires speed information of the autonomous vehicle; a position acquisition unit 3 that acquires position information of the autonomous vehicle relative to a stopping position corresponding to a signal identified by the signal recognition unit 13; and a forward / stop determination unit 14 that, when a signal is identified by the signal recognition unit 13, determines at a predetermined period whether the autonomous vehicle should move forward or stop based on the illumination state of the signal identified by the signal recognition unit 13, the speed information acquired by the speed acquisition unit 2, and the position information acquired by the position acquisition unit 3. Figure 3 ).

[0036] The forward / stop determination unit 14 also determines whether the autonomous vehicle should move forward or stop based on the previous determination result and the signal illumination status previously identified by the signal recognition unit 13. Figure 5 In this way, by considering the previous judgment result and the signal illumination status to make the current forward / stop judgment, the forward / stop judgment can be made appropriately and stably, thus enabling good vehicle driving control based on the forward / stop judgment result.

[0037] (2) The signal recognition unit 13 recognizes the illuminated state of the signal as any one of the following: a green signal G that allows vehicles to proceed, a yellow signal Y that prohibits vehicles from crossing the stop position except in cases where it is not safe to stop, a red signal R that prohibits vehicles from proceeding, and an undefined state U that is unclear as to which of the green signal G, yellow signal Y, or red signal R it is. Figure 5 When the signal recognition unit 13 recognizes a green signal G, the forward stop determination unit 14 determines that the autonomous vehicle should proceed directly. When the signal recognition unit 13 recognizes a yellow signal Y, it determines that the vehicle should stop at the stop position corresponding to the signal recognized by the signal recognition unit 13, unless the autonomous vehicle cannot stop safely. When the signal recognition unit 13 recognizes a red signal R, it determines that the vehicle should stop at the stop position corresponding to the signal recognized by the signal recognition unit 13, unless the autonomous vehicle has already passed the stop position. Figure 5 In this way, by recognizing the color of the signal and determining whether to proceed or stop based on the recognized signal color, the driving control of autonomous vehicles can be appropriately performed even on ordinary roads with traffic signals.

[0038] (3) If the signal recognition unit 13 previously identified the signal's illumination state as "unknown" (U), and the signal recognition unit 13 currently identifies the signal's illumination state as "yellow signal" (Y), regardless of the speed and position information, the forward / stop determination unit 14 determines whether the autonomous vehicle should move forward or stop based on the previous determination result. Figure 5 In this way, if a signal color was not recognized in the previous test but a yellow signal is recognized in the current test, the previous forward / stop determination result will be maintained regardless of the speed and position of the autonomous vehicle. This ensures the stability of the forward / stop determination result and reliably suppresses unnecessary deceleration during driving control.

[0039] In the above embodiments, Figure 4 The example described above illustrates that the signal recognition unit 13 and the forward / stop determination unit 14 process the signal periodically according to the shooting cycle of the camera 1. However, the signal recognition unit, which identifies the signal and its illumination status at a predetermined cycle, and the forward / stop determination unit, which determines whether the autonomous vehicle should move forward or stop, are not limited to this. For example, processing can be performed according to each operation cycle of the ECU, and the processing cycle can be changed according to the vehicle's position, vehicle speed, etc.

[0040] In the above embodiments, an example was described where the speed acquisition unit 2 is composed of a wheel speed sensor or the like, and the position acquisition unit 3 is composed of a positioning sensor. However, the speed acquisition unit that acquires the speed information of the autonomous vehicle and the position acquisition unit that acquires the position information of the autonomous vehicle are not limited to these. For example, position information can also be acquired using autonomous navigation, and speed information can also be acquired based on the position information.

[0041] It is possible to combine one or more of the above-described embodiments and variations, and to combine the variations with each other.

[0042] Using this invention, it is possible to reliably determine whether an autonomous vehicle should move forward or stop.

[0043] The present invention has been described above in conjunction with preferred embodiments, but those skilled in the art should understand that various modifications and alterations can be made without departing from the scope of the following claims.

Claims

1. A forward stop determination device (100), characterized in that, have: Camera (1), which is mounted on an autonomous vehicle, acquires image information of the autonomous vehicle's forward direction; The signal recognition unit (13) identifies the traffic lights in the forward direction of the autonomous vehicle at a predetermined period based on the image information obtained by the camera (1), and identifies the lighting state of the identified traffic lights; the signal recognition unit (13) identifies the lighting state of the traffic lights as any one of the following: a first lighting state that allows the vehicle to move forward, namely a green signal; a second lighting state that prohibits the vehicle from moving forward beyond the stop position except in cases where it cannot be stopped safely, namely a yellow signal; a third lighting state that prohibits the vehicle from moving forward, namely a red signal; and an unknown state that does not know which of the first lighting state to the third lighting state it is. Speed ​​acquisition unit (2) acquires the speed information of the autonomous vehicle; The position acquisition unit (3) acquires the position information of the autonomous vehicle relative to the stop position corresponding to the signal identified by the signal recognition unit (13); as well as The forward / stop determination unit (14) determines whether the autonomous vehicle should move forward or stop when the signal recognition unit (13) recognizes a signal. This determination is based on the lighting status of the signal recognized by the signal recognition unit (13), the speed information obtained by the speed acquisition unit (2), the position information obtained by the position acquisition unit (3), the previous determination result, and the lighting status of the signal recognized by the signal recognition unit (13) in the previous period. When the signal recognition unit (13) recognizes the first lighting state, regardless of the previous lighting state of the signal, the area A to E corresponding to the vehicle speed and vehicle position, or the previous forward / stop judgment result, it is judged to move forward. When the signal recognition unit (13) recognizes the second illumination state, except in cases where the autonomous vehicle cannot stop safely, it is determined that the vehicle should stop at the stop position corresponding to the signal recognized by the signal recognition unit (13). When the signal recognition unit (13) recognizes the third illumination state, except in the case where the autonomous vehicle has already passed the stop position, it is determined that it should stop at the stop position corresponding to the signal recognized by the signal recognition unit (13); When the signal recognition unit (13) previously identified an unknown state and now identifies a yellow signal or an unknown state, the forward stop determination unit (14) maintains the previous forward stop determination result as the current forward stop determination result regardless of regions A to E. When the forward stop determination unit (14) identifies a green signal by the signal recognition unit (13) last time and determines to move forward, and identifies a yellow signal or an unknown state this time, it determines to move forward in the case of region A, C, and D, and to stop in the case of region B and E. In regions A, C, and D, if the signal recognition unit (13) previously identified a yellow signal and the forward stop determination unit (14) determined that the signal should move forward, and if a yellow signal is identified this time, the signal should be determined to move forward. In regions B and E, if the signal recognition unit (13) previously identified a yellow signal and the forward stop determination unit (14) determined that the signal should be stopped, and if a yellow signal is identified this time, the signal should be determined to be stopped. In region A, if the signal recognition unit (13) previously identified a yellow signal, a red signal, or an unknown state, and the forward stop determination unit (14) determined that the signal was moving forward, and the signal recognition unit (13) identifies a red signal or an unknown state this time, the signal recognition unit (13) determines that the signal is moving forward. In regions B and E, if the signal recognition unit (13) previously identified a yellow signal, a red signal, or an unknown state, and the signal recognition unit (14) determined that the signal was stopped, and the signal recognition unit (14) identifies a red signal or an unknown state this time, the signal recognition unit (13) determines that the signal is stopped. Zone A corresponds to the position of vehicles that have already passed the stop position; Zones B to E correspond to the positions of vehicles that are still in front of the stop position. Zones B and C correspond to the positions and speeds of vehicles that can slow down and stop at the stop position; Zones D and E correspond to the positions and speeds of vehicles that cannot slow down and stop safely at the stop position. Zones C and D correspond to the positions and speeds of vehicles that will pass the stop position before the red signal appears if they continue driving at the same speed. Zones B and E correspond to the positions and speeds of vehicles that will pass the stop position after the red signal appears if they continue driving at the same speed.

2. The forward stop determination device (100) according to claim 1, characterized in that, The signal recognition unit (13) identifies the signal in the forward direction of the autonomous vehicle at a predetermined period corresponding to the shooting period of the camera (1), and identifies the lighting status of the identified signal.

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