Vehicle control device and warning control system

Abstract

The present invention comprises: a crossing vehicle detection unit that detects another vehicle approaching so as to cross the path of travel of a host vehicle; an intersection point detection unit that detects an intersection point of the host vehicle and the other vehicle on the basis of movement predictions regarding the host vehicle and the other vehicle; a warning determination unit that determines whether the host vehicle and the other vehicle will collide at the detected intersection point and outputs a warning upon determining that a collision will occur; a road shape determination unit that determines whether the other vehicle will cross the path of travel of the host vehicle on the basis of the road shape of the path of travel of the host vehicle; and a warning permission determination unit that determines, on the basis of a determination result from the road shape determination unit, whether to set a warning function of the warning determination unit to permitted.

Description

Vehicle control device and warning control method

[0001] The present invention relates to a vehicle control device that controls a collision warning function.

[0002] Automotive millimeter-wave radar is a sensor that detects the vehicle's surroundings in real time. It emits radio waves (millimeter waves) into the space around the vehicle and processes the reflected waves from surrounding targets (vehicles ahead, pedestrians, cyclists, and other vulnerable road users, obstacles such as guardrails and utility poles, etc.) to estimate information such as the target's distance, speed, and angle.

[0003] The collision warning device determines the possibility of a collision between the vehicle and a target based on the distance and speed of the target estimated using information obtained by sensors that recognize the vehicle's surroundings, such as the millimeter-wave radar or camera mentioned above, and if there is a high possibility of a collision, it notifies the driver of the danger by means of sound, lights, etc., and urges the driver to avoid the collision.

[0004] In particular, FCTA (Front Cross Traffic Alert) systems, which encourage drivers to avoid collisions with vehicles crossing in front of their own vehicle, are widely installed in vehicles, primarily to prevent head-on collisions at intersections without traffic lights.

[0005] The following prior art exists as background art in this technical field: Patent Document 1 (JP 2020-123155 A) describes a peripheral object identification device that, when a tracking object occurs that is located to the left of the host vehicle and whose distance to the host vehicle does not change because the host vehicle is traveling on the right side of a guardrail or there is another vehicle traveling alongside the host vehicle to the left, checks whether there is another tracking object in addition to the tracking object, located to the left front of the host vehicle, that is in line with the tracking object and has a relative speed equal to the vehicle speed in the opposite direction to the traveling direction of the host vehicle, and if such an object is present, identifies the tracking object as a fixed roadside object.

[0006] Japanese Patent Application Laid-Open No. 2020-123155

[0007] Conventional crossing vehicle collision warning systems are designed for general crossroads or T-junctions, and have difficulty responding to unexpected road shapes or target lane changes.

[0008] As shown in FIG. 1 , a conventional crossing vehicle collision warning system 000 uses a crossing vehicle detection unit 001 to detect the distance and speed of a target, and a crossing vehicle prediction unit 002 to predict the movement of the target. A host vehicle movement prediction unit 003 predicts the movement of the host vehicle from the host vehicle speed and steering angle. An intersection point detection unit 004 detects the intersection point of the predicted movements of the host vehicle and the target based on these two movement predictions. A warning determination unit 006 determines whether a collision will occur based on this intersection point. A turn signal detection unit 005 detects whether the target's turn signal is on and outputs the detection result to the warning determination unit 006. If the target's turn signal is on, the warning determination unit 006 sets the warning to off because the possibility of the target traveling straight is extremely low.

[0009] As shown in FIG. 2, in a case where the conventional crossing vehicle collision warning system 000 is problematic, the target vehicle side at a T-junction is the main lane, and it is possible to proceed to the left without turning on the left turn signal.

[0010] In this case, the crossing vehicle collision warning system 000 determines that a collision is highly likely, so the warning is set to on. Next, because the left turn signal is not illuminated, the false warning prevention function does not function, and a warning is issued to the driver. As a result, the warning is issued even though the collision possibility is extremely low, and the driver finds the warning annoying. This reduces the driver's confidence in the collision warning system, and because the warning issued in a case where a collision possibility is high is not trusted, the driver is not prompted to take action to avoid the collision, which may result in a traffic accident due to a collision.

[0011] Another problematic case in conventional crossing vehicle collision warning systems is a crossroads where the lane of the vehicle and the lane of the target cross at an angle (e.g., 60 to 30 degrees) rather than at 90 degrees, as shown in Figure 3. Hereinafter, in this specification, the angle at which the vehicle and the target cross is referred to as the crossing angle.

[0012] In conventional crossing vehicle collision warning systems, the warning determination unit 006 often has a function of turning off the warning to prevent false warnings when the crossing angle is significantly different from 90 degrees (for example, outside the range of 90 degrees ±5 degrees to ±20 degrees). Therefore, in the case shown in Figure 3, even if there is a possibility of a collision, no warning is sent to the driver, and even if the driver does not recognize the crossing vehicle, there is a possibility that a collision will occur and a traffic accident will occur.

[0013] Therefore, the present invention aims to provide a highly reliable collision warning system that does not bother the driver, even at T-junctions and crossroads such as those mentioned above, by determining scenes that require an alarm and scenes that do not require an alarm from information obtained by sensors that recognize the vehicle's surroundings, such as millimeter-wave radar or cameras, and switching whether to issue an alarm.

[0014] A representative example of the invention disclosed in the present application is as follows: That is, the vehicle detection system includes a crossing vehicle detection unit that detects another vehicle approaching so as to cross a traveling path of the host vehicle, an intersection point detection unit that detects an intersection point of the host vehicle and the other vehicle based on a movement prediction of the host vehicle and the other vehicle, an alarm determination unit that determines whether the host vehicle and the other vehicle will collide at the detected intersection point and outputs an alarm when it is determined that a collision will occur, a road shape determination unit that determines whether the other vehicle will cross the traveling path of the host vehicle based on a road shape in the traveling direction of the host vehicle, and an alarm permission determination unit that determines whether to enable an alarm function of the alarm determination unit based on a determination result by the road shape determination unit.

[0015] According to one aspect of the present invention, whether to output an alarm can be appropriately switched. Problems, configurations, and effects other than those described above will become apparent from the following description of the embodiments.

[0016] 1 is a block diagram of a conventional crossing vehicle collision warning system; FIG. 2 is a diagram showing a case (a T-junction where the target side is the main road) that poses a problem in the conventional crossing vehicle collision warning system; FIG. 3 is a diagram showing a case (a crossroad where the intersection angle is not 90 degrees) that poses a problem in the conventional crossing vehicle collision warning system; FIG. 4 is a block diagram of a crossing vehicle collision warning system according to a first embodiment of the present invention; FIG. 5 is a diagram showing a case (a T-junction where the target side is the main road) for explaining the operation of the crossing vehicle collision warning system according to the first embodiment of the present invention; FIG. 6 is a logic table showing the operation of the crossing vehicle collision warning system according to the first embodiment of the present invention; FIG. 7 is a flowchart of processing executed by the crossing vehicle collision warning system according to the first embodiment of the present invention; FIG. 8 is a diagram showing a case (a crossroad where the intersection angle is not 90 degrees) for explaining the effect of the crossing vehicle collision warning system according to the first embodiment of the present invention; FIG. 1 is a diagram illustrating a case for explaining the operation of a function added in the crossing vehicle collision warning system of embodiment 2 of the present invention; FIG. 2 is a flowchart of the processing performed by the crossing vehicle collision warning system of embodiment 2 of the present invention; FIG. 3 is a diagram illustrating a case for explaining the operation of a function added in the crossing vehicle collision warning system of embodiment 3 of the present invention; FIG. 4 is a diagram illustrating a case for explaining the operation of a function added in the crossing vehicle collision warning system of embodiment 3 of the present invention; FIG. 5 is a flowchart of the processing performed by the crossing vehicle collision warning system of embodiment 3 of the present invention.

[0017] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0018] First Embodiment First, a crossing vehicle collision warning system 100 according to a first embodiment of the present invention will be described in detail.

[0019] <Outline of Crossing Vehicle Collision Warning System 100> FIG. 4 is a block diagram of the crossing vehicle collision warning system 100 according to the first embodiment.

[0020] The crossing vehicle collision warning system 100 has a crossing vehicle detection unit 101, a crossing vehicle prediction unit 102, a vehicle movement prediction unit 103, an intersection detection unit 104, a turn signal detection unit 105, a warning judgment unit 106, and a road shape judgment unit 107.

[0021] The crossing vehicle detection unit 101 detects the distance and speed of the target. The crossing vehicle prediction unit 102 predicts the movement of the target. The host vehicle movement prediction unit 103 predicts the movement of the host vehicle based on the host vehicle speed and steering angle. The intersection detection unit 104 detects an intersection point between the host vehicle and the target based on the predicted movements of the host vehicle and the target. The warning determination unit 106 determines whether the host vehicle and the target will collide at the detected intersection point, and outputs a warning if a collision is determined. The turn signal detection unit 105 detects the operating state of the target's turn signal. Furthermore, in the crossing vehicle collision warning system 100 of the first embodiment, the road shape determination unit 107 determines the road shape in the traveling direction of the host vehicle based on information acquired from a millimeter-wave radar or a camera. The warning permission determination unit 108 receives information output from the turn signal detection unit 105 and the road shape determination unit 107 and determines whether to permit or prohibit the issuance of a warning.

[0022] The vehicle control device constituting the crossing vehicle collision warning system 100 is an electronic control unit having an arithmetic device, a storage device, and a communication interface. The arithmetic device is a processor (e.g., a microcomputer) that executes programs stored in the storage device. The arithmetic device operates as a functional block that provides various functions by executing predetermined programs. The storage device includes a non-volatile storage area and a volatile storage area. The non-volatile storage area is accessible by the arithmetic device and includes a program area that stores programs executed by the arithmetic device, and a data area that temporarily stores data used by the arithmetic device when executing programs. The volatile storage area stores data used by the arithmetic device when executing programs. The communication interface connects to other electronic control units via a network such as CAN or Ethernet.

[0023] The road shape determining unit 107 and the warning permission determining unit 108, which are key features of the present invention, will now be described in detail.

[0024] <Explanation of Road Shape Determination Unit 107> The road shape determination unit 107 determines that crossing is not possible (i.e., the target does not go straight, but goes left or right) when at least one of the following conditions is met: - Radar or camera detects an object (wall, guardrail, outer lane markings of the road, etc.) that obstructs the target's progress in the direction of travel - Camera detects a T-junction sign

[0025] Therefore, if the above conditions are not met as follows, the road shape determination unit 107 determines that the road is crossable: The radar or camera does not detect an object that obstructs the target's progress in the direction of travel, and the camera does not detect a T-junction sign (for example, when there is no T-junction sign or when a crossroad sign is detected).

[0026] Next, we will explain how radar detects obstacles to the progress of a target (for example, walls, guardrails, etc.). If the positions of points detected by radar are distributed within a certain interval in the forward and backward directions and within a certain range in the horizontal direction, the distributed point cloud is a reflection point from a wall, guardrail, etc., and it can be determined that an object obstructing the progress of the target is present.

[0027] Furthermore, if the camera detects a white line in the direction the target is crossing, or detects a cliff on a riverbed or the like, it determines that there is an object obstructing the target's progress.

[0028] 5 shows an example in which the road shape determination unit 107 determines that an object obstructing travel is present. In the case of FIG. 5, there is a wall in the direction of travel of the target, and the wall on the left side of the vehicle is detected by radar, or a T-junction sign is detected by a camera. The target approaching from the right crosses in front of the vehicle and does not proceed to the left, satisfying the aforementioned condition for determining that crossing is not permitted. Therefore, the warning permission determination unit 108, which will be described later, determines that this is not a scene in which a warning should be issued, and the warning is set to off even if the intersection detection unit 104 predicts a collision.

[0029] <Explanation of Warning Permission Determination Unit 108> Next, a description will be given of the warning permission determination unit 108. The warning permission determination unit 108 determines whether to permit or prohibit the issuance of a warning based on the determination result of whether crossing is possible or not by the road shape determination unit 107 and the detection result of the left or right turn indicator by the turn indicator detection unit 105.

[0030] 5 and 6, a method for determining whether to permit or prohibit issuing an alarm will be described. When the road shape does not allow crossing, the target will not move in a direction that would cross in front of the vehicle, and therefore there is a possibility that the target will turn left or right. Next, if the detection result of the turn signal detector 105 shows that the right turn signal is on, it is determined that the target will turn right and there is a possibility of a collision with the vehicle, and therefore the alarm is set to permit. On the other hand, if the right turn signal is not on, it is determined that the target will not move in a direction that would cross in front of the vehicle, but will turn left, and therefore there is no possibility of a collision with the vehicle, and therefore the alarm is set to prohibit.

[0031] In the illustrated example, the target is approaching from the right of the host vehicle, and there is a wall on the left side of the host vehicle, so the target cannot proceed straight ahead. However, there may be cases where the target is approaching from the left of the host vehicle, and there is a wall on the right side of the host vehicle. Generally speaking, if the detection result of the turn signal detector 105 shows that the target is not on the opposite side of the host vehicle and the turn signal far from the host vehicle is on, the host vehicle and the target are traveling in the same direction, which could lead to a collision between the host vehicle and the target. Therefore, the warning is set to "permitted." On the other hand, if the target is not on the opposite side of the host vehicle and the turn signal far from the host vehicle is not on, the target will turn left instead of proceeding in a direction that crosses in front of the host vehicle, so there is no possibility of a collision with the host vehicle, and the warning is set to "prohibited."

[0032] Next, a case will be described where it is determined that the target can cross in front of the vehicle based on the road shape. If it is determined that crossing is possible, there is a possibility that the target will proceed in a direction that will cross in front of the vehicle, and therefore the target may turn left, turn right, or go straight. Here, if crossing is possible, the detection result of the turn signal on the left (in the direction of the vehicle) is referenced. The reason for this will be explained below.

[0033] The target's travel directions that may result in a collision between the own vehicle and the target are when the target turns right and enters the same lane as the own vehicle, or when the target continues traveling straight and crosses in front of the own vehicle, but when the target turns left, it can be considered that there is no possibility of a collision. For example, by looking at the right turn signal, it is possible to determine whether the target is turning right, but whether the target turns right or not (goes straight or turns left) still has the possibility of a collision with the own vehicle, so it is not possible to clearly distinguish whether there is a possibility of a collision. Therefore, the detection result of the left turn signal is referenced instead of the right turn signal. This makes it possible to determine whether the target is turning left. Then, it is possible to clearly determine whether there is a possibility of a collision by determining that there is no possibility of a collision if the target turns left, and that there is a possibility of a collision if the target does not turn left (goes right or goes straight).

[0034] Therefore, as shown in FIG. 5, if crossing is possible and the left turn signal is on, it is determined that the target will turn left, so there is no possibility of a collision between the vehicle and the target, and the warning is set to off. On the other hand, if crossing is possible and the left turn signal is not on, it is determined that the target will not turn left (i.e., will turn right or go straight), so there is a possibility of a collision, and the warning is set to allow.

[0035] <Flowchart of Crossing Vehicle Collision Warning System 100> FIG. 7 is a flowchart of the process executed by the crossing vehicle collision warning system 100 of the first embodiment.

[0036] The road shape determination unit 107 determines whether crossing is possible or not. Specifically, the road shape determination unit 107 determines whether there is an object that obstructs the progress of the target or whether there is a T-junction sign (S11), and if there is an object that obstructs the progress of the target or there is a T-junction sign, determines that the target cannot cross in front of the vehicle (S12). On the other hand, if there is no object that obstructs the progress of the target and there is no T-junction sign, the road shape determination unit 107 determines that the target can cross in front of the vehicle (S13).

[0037] The warning permission determination unit 108 determines whether to permit or prohibit the issuance of a warning based on the determination result by the road shape determination unit 107 and the detection result of the left or right turn signal by the turn signal detection unit 105. Specifically, if the road shape determination unit 107 determines that crossing is not permitted (Yes in S15), the warning permission determination unit 108 determines whether the turn signal on the right side of the target is detected (S16). If the turn signal on the right side of the target is detected, the target will turn right and interfere with the straight-ahead path of the vehicle, so the warning permission determination unit 108 sets the warning to permit (S17). On the other hand, if the turn signal on the right side of the target is not detected, the target will turn left and will not interfere with the straight-ahead path of the vehicle, so the warning permission determination unit 108 sets the warning to prohibit (S18).

[0038] The warning permission determination unit 108 in the first embodiment determines whether crossing is permitted based on the road shape and the lighting status of the target's turn signal, but may determine whether to permit or prohibit warning based on either one of them.

[0039] On the other hand, if the road shape determination unit 107 determines that crossing is possible (No in S15), the warning permission determination unit 108 determines whether the left turn signal of the target is detected (S19), and if the left turn signal of the target is detected, the target will turn left and will not interfere with the straight-ahead path of the vehicle, so the warning is set to prohibited (S20).On the other hand, if the left turn signal of the target is not detected, the warning permission determination unit 108 sets the warning to permitted (S21), because the target will turn right or go straight and will interfere with the straight-ahead path of the vehicle.

[0040] Next, the warning determination unit 106 determines whether there is a possibility of a collision between the vehicle and the target based on the position and speed of the target (S22), and sets the warning to off if there is no possibility of a collision (S26). On the other hand, if there is a possibility of a collision, the warning determination unit 106 switches the warning on or off depending on the determination result of the warning permission determination unit 108. That is, if the warning permission determination unit 108 determines that the warning is permitted (Yes in S23), the warning determination unit 106 sets the warning to on (S24). On the other hand, if the warning permission determination unit 108 determines that the warning is prohibited (No in S23), the warning determination unit 106 sets the warning to off (S25).

[0041] <Effects of this embodiment> As described above, according to the crossing collision warning system of this embodiment, a scene in which an alarm should be issued and a scene in which an alarm should not be issued are determined from information obtained by a sensor that recognizes the situation around the vehicle, such as a millimeter-wave radar or a camera, and the alarm is switched on and off, thereby providing a collision warning system that is not inconvenient for the driver and is highly reliable.

[0042] The effects of this embodiment will be described below with reference to actual use cases.

[0043] Case 1: Intersection (the intersection angle between the vehicle and the target is not 90 degrees) Figures 8A and 8B show the cases of an intersection where the intersection angle between the roads is not 90 degrees, in which the target turns left and goes straight.

[0044] As shown in FIG. 8A, when the target turns left, the crossing collision warning system of this embodiment determines that the scene does not require an alert because the left turn signal is on, and sets the alert to off.

[0045] As shown in Figure 8B, when the target is traveling straight, the crossing collision warning system of this embodiment determines that the target is capable of crossing and the left turn signal is not illuminated, regardless of the shape of the intersection angle, and therefore determines that there is a possibility of the target traveling straight or turning right, and sets the warning to "permit." As mentioned above, conventional crossing vehicle collision warning systems may set the warning to "off" at intersections where the intersection angle is not 90 degrees to prevent false warnings, which may result in the warning not being issued. The crossing collision warning system of this embodiment can improve the problem of non-issues of warnings (events in which a warning should be issued but is not issued).

[0046] Case 2: T-junction (when the target is on the main line) Figures 9A and 9B show a T-junction where there is a curved main line connecting the vehicle and the target, and the target can proceed left without turning on the left turn signal.

[0047] As shown in Figure 9A, when the target is traveling left, the crossing collision warning system of this embodiment determines that there is no possibility of a right turn because the right turn signal is not on, and that there is a wall in the direction of travel, making it impossible to cross, and therefore there is no possibility of traveling straight. Therefore, it determines that the target is turning left, and sets the alarm to off to prevent a false alarm. On the other hand, in a conventional crossing collision warning system, the possibility of the target traveling straight and crossing the path of the vehicle is not ruled out, and it determines that there is a high possibility of a collision with the target, so sets the alarm to on. And because the left turn signal is not on, a false alarm is not prevented, and a false alarm is issued.

[0048] 9B, when the target turns right, the crossing collision warning system of this embodiment detects that the right turn signal is on, so the warning is enabled and the warning is set to ON or OFF depending on the possibility of a collision. Similarly, in the conventional crossing collision warning system, the warning is set to ON or OFF depending on the possibility of a collision with the target.

[0049] As described above, the crossing collision warning system according to an embodiment of the present invention determines road geometry from information acquired by a sensor (e.g., millimeter-wave radar, camera) that recognizes the vehicle's surroundings and predicts whether the target vehicle will turn left or right based on whether its turn signal is on or off. Then, based on the left or right turn prediction, it determines whether a warning should be issued or not. For a scene in which a warning should be issued, the system turns the warning on if there is a possibility of a collision based on the collision prediction, and turns the warning off if there is no possibility of a collision. For a scene in which a warning should not be issued, the system turns the warning off regardless of the possibility of a collision based on the collision prediction. This reduces false warnings when the target turns left, a problem with conventional systems, and enables the system to turn the warning on or off depending on the possibility of a collision, achieving warnings equivalent to those of conventional systems. Therefore, by determining whether a warning should be issued or not and switching the warning on or off, a highly reliable collision warning system that does not bother the driver can be provided.

[0050] Second Embodiment A crossing vehicle collision warning system 100 according to a second embodiment of the present invention will be described in detail. In the following, differences from the first embodiment will be mainly described, and descriptions of the same configurations and processes as the first embodiment will be omitted.

[0051] In the first embodiment, the alarm is enabled or disabled based on the likelihood of the target crossing and the illumination status of the turn signal. However, although the legal timing for turning on the turn signal is 30 meters before the intersection, the timing for turning on the turn signal varies from driver to driver. In particular, since the main cases to which the present invention is applied are intersections without traffic lights, drivers are less conscious of turning on the turn signal than at intersections with traffic lights. In actual operating environments, there are cases where drivers turn on the turn signal when they are closer than 30 meters. Therefore, the timing for turning on the turn signal varies from driver to driver. In such cases, the timing for turning off the alarm is determined by the illumination timing of the turn signal. If the alarm is issued before the illumination of the turn signal, the alarm will be turned off when the turn signal is illuminated, and the driver may feel as if the alarm has suddenly disappeared.

[0052] For example, if the TTC (Time To Collision), which is the time until a collision between the target and the vehicle, is 2 seconds and an alarm is issued before that, assuming the target speed is 60 km / h, the distance between the vehicle and the target at the time the alarm is issued will be approximately 33 m. If the turn signal is turned on 30 m before the target in accordance with the law, depending on the timing of the light, the alarm may be internally overwritten to off before the alarm is issued, even though an internal alarm is issued. Therefore, if the target is traveling straight ahead, crossing in front of the vehicle, the driver may not be notified of the alarm, and the driver may feel that the alarm is not activated.

[0053] For this reason, it is desirable to appropriately control the timing for turning off the alarm in the control of Example 1. Therefore, in Example 2, a function for solving the above-described problem of Example 1 is added.

[0054] FIG. 10 is a diagram showing a case for explaining the operation of a function added to the crossing vehicle collision warning system of this embodiment.

[0055] The additional function of the second embodiment is to first set the position of the stop line detected by the external recognition sensor as the "alarm-off start line." Next, when an alarm is issued before this alarm-off start line, the timing of turning off the alarm is delayed until the "alarm-off start line" even if the alarm-off determination conditions shown in FIG. 5 of the first embodiment are satisfied.

[0056] The control flow will be described in detail with reference to FIG. 10 . Note that FIG. 10 will be described assuming that the target turns left after passing the stop line. First, at timing (1) in FIG. 10 , it is determined that there is a possibility of a collision from the predicted intersection point between the target and the host vehicle, and the alarm is set to ON. Next, it is determined that crossing is not possible because there is a wall on the left side of the host vehicle, and when the driver of the target turns on the turn signal at timing (2), the condition for turning the alarm off is met. Here, if the control described in Example 1 is used, the alarm is set to OFF at timing (2), and as described above, no alarm is issued even if the target is traveling straight, so the driver may feel that the alarm is not activated.

[0057] Therefore, the alarm is not set to off at timing (2), but the timing at which the alarm is turned off is delayed so that it is set to off at timing (3) when the target crosses the stop line. Since the target starts to turn left after timing (3), if the alarm remains on, the driver will likely perceive it as a false alarm. For this reason, as in Example 1, the alarm is set to off based on whether the target can cross and the lighting status of the turn signal.

[0058] In addition to detecting the stop line with a camera, the stop line position may be obtained from map information or by other means. If the stop line cannot be detected, the position of the gap in the intersection detected by the camera or radar may be set as the "warning off start line."

[0059] <Flowchart of Crossing Vehicle Collision Warning System 100> FIG. 11 is a flowchart of the process executed by the crossing vehicle collision warning system 100 according to the second embodiment.

[0060] Steps S11 to S24 of the processing of the crossing vehicle collision warning system 100 of the second embodiment are the same as the processing of the crossing vehicle collision warning system 100 of the first embodiment described above.

[0061] In step S23, if the alarm permission determination unit 108 determines that an alarm should be permitted (Yes in S23), the alarm determination unit 106 sets the alarm to ON (S24). On the other hand, if the alarm permission determination unit 108 determines that an alarm should be prohibited (No in S23), the alarm determination unit 106 determines whether the target position is beyond the alarm-off start line (S27). Then, if the target position is beyond the alarm-off start line, the alarm determination unit 106 sets the alarm to OFF (S25). On the other hand, if the target position is not beyond the alarm-off start line, the alarm determination unit 106 sets the alarm to ON (S28) and delays the timing at which the alarm-off starts.

[0062] <Effects of this embodiment> As described above, the crossing collision warning system of this embodiment improves on the failure to warn and false warnings of the conventional system as shown in embodiment 1, and when a target is crossing the road and there is a possibility of a collision, the warning can be continued without being interrupted by lighting up the turn signal, thereby providing a highly reliable collision warning system.

[0063] Third Embodiment A crossing vehicle collision warning system 100 according to a third embodiment of the present invention will be described in detail. In the following, differences from the first and second embodiments will be mainly described, and descriptions of the same configurations and processes as the first and second embodiments will be omitted.

[0064] 12A and 12B are diagrams showing a case for explaining the operation of a function added to the crossing vehicle collision warning system of this embodiment, and show a state in which the target and the own vehicle are traveling at a position and speed that will cause them to collide at an intersection, and the crossing vehicle collision warning system 100 determines that there is a possibility of a collision and issues a warning.

[0065] In the state shown in Figure 12A, the vehicle is traveling at a speed above a predetermined speed or accelerating, and the driver may not have predicted a collision with the target before the alarm is issued. Therefore, by notifying the driver of the danger with an alarm such as an audible alarm, the driver is encouraged to take action to avoid the collision, thereby preventing an accident. In the state shown in Figure 12B, the vehicle is traveling at a speed that is likely to cause the vehicle to stop. Before the alarm is issued, it is estimated that the driver is observing the surroundings while driving, and it is highly likely that the driver predicted a collision with the target and reduced their speed to avoid the collision. Therefore, in this case, the driver may find the audible alarm excessive and annoying.

[0066] Therefore, when the warning is on and the vehicle speed satisfies at least one of the following conditions, it is assumed that the driver is driving without being able to predict a collision with the target, and an audible warning is output: - The vehicle speed is equal to or greater than a threshold (the speed threshold is set to 5 km / h, 10 km / h, etc.) - The vehicle acceleration / deceleration is equal to or greater than a threshold (the acceleration / deceleration threshold is set to 2 m / s 2 , 4 m / s 2 etc.)

[0067] The aforementioned speed and acceleration / deceleration thresholds may be fixed values ​​set at the time of vehicle shipment, or may be variable depending on the estimated time to collision (TTC) (for example, the thresholds may be reduced when the estimated time to collision is short).

[0068] The vehicle speed is acquired from the vehicle speed sensor, and the vehicle acceleration / deceleration is calculated from the time difference of the vehicle speed using the following formula: Acceleration / deceleration [n] = (Speed ​​[n] - Speed ​​[n-1]) / Speed ​​reception period Acceleration / deceleration unit: m / s 2 Speed ​​unit: m / s Speed ​​reception cycle unit: s

[0069] On the other hand, if none of the above conditions are satisfied, it is assumed that the driver is observing the surroundings, predicting a collision with the target, and slowing down to avoid the collision, and a warning is output by display (lighting up a lamp, displaying on the LCD screen) rather than by sound.

[0070] The acceleration / deceleration condition and the speed condition may be used together or either one of them may be used. Also, it may be possible to switch between using the acceleration / deceleration condition and the speed condition depending on the conditions.

[0071] <Flowchart of Crossing Vehicle Collision Warning System 100> FIGS. 13A and 13B are flowcharts of the process executed by the crossing vehicle collision warning system 100 according to the third embodiment.

[0072] Steps S11 to S28 of the processing of the crossing vehicle collision warning system 100 of the third embodiment are the same as the processing of the crossing vehicle collision warning system 100 of the second embodiment described above.

[0073] Next, after step S24, S25, S26, or S28, the warning determination unit 106 determines whether the set warning is turned on (S29). If the warning is turned off, the warning is turned off (S30). On the other hand, if the warning is turned on, the warning determination unit 106 determines whether the vehicle speed is equal to or greater than a predetermined threshold, or whether the vehicle acceleration / deceleration is equal to or greater than a predetermined threshold (S31).

[0074] If the vehicle speed is equal to or greater than a predetermined threshold, or if the vehicle acceleration / deceleration is equal to or greater than a predetermined threshold, it is assumed that the driver is traveling without being able to predict a collision with the target, and an audible warning is output (S32). On the other hand, if the vehicle speed is smaller than the predetermined threshold and the vehicle acceleration / deceleration is smaller than the predetermined threshold, it is assumed that the driver is observing the surroundings, predicting a collision with the target, and reducing the vehicle speed to avoid the collision, and an audible warning is not output, but a visual warning is output (S33).

[0075] <Effects of this embodiment> As described above, the crossing collision warning system of this embodiment can suppress the failure to warn and false alarms of conventional systems, and when a target is crossing the road and there is a possibility of a collision, the warning output can be continued without being interrupted by turning on the turn signal, thereby providing a highly reliable collision warning system.

[0076] The present invention is not limited to the above-described embodiments, and includes various modifications and equivalent configurations within the spirit and scope of the appended claims. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to configurations including all of the described configurations. Furthermore, part of the configuration of one embodiment may be replaced with the configuration of another embodiment. Furthermore, the configuration of another embodiment may be added to the configuration of one embodiment. Furthermore, part of the configuration of each embodiment may be added, deleted, or replaced with other configurations.

[0077] For example, the crossing vehicle detection unit 101 is not limited to a millimeter-wave radar, and may be configured with a stereo camera, LiDAR, laser radar, etc., as long as it can detect a target crossing in front of the vehicle. Furthermore, the road shape determination unit 107 does not need to make a determination using information obtained by an external recognition sensor such as the millimeter-wave radar described above, but may make a determination using map information or road shapes obtained from an external device via V2X (Vehicle To Everything).

[0078] Furthermore, the aforementioned configurations, functions, processing units, processing means, etc. may be realized in part or in whole in hardware, for example by designing them as integrated circuits, or may be realized in software by a processor interpreting and executing a program that realizes each function.

[0079] Information such as programs, tables, and files that realize each function can be stored in a storage device such as a memory, hard disk, or SSD (Solid State Drive), or in a recording medium such as an IC card, SD card, or DVD.

[0080] In addition, the control lines and information lines shown are those that are considered necessary for the explanation, and do not necessarily show all the control lines and information lines that are necessary for implementation. In reality, it can be considered that almost all components are interconnected.

Claims

1. A vehicle control device comprising: a crossing vehicle detection unit that detects another vehicle approaching and crossing the travel path of the host vehicle; an intersection point detection unit that detects an intersection point between the host vehicle and the other vehicle based on predicted movements of the host vehicle and the other vehicle; an alarm determination unit that determines whether the host vehicle and the other vehicle will collide at the detected intersection point and outputs an alarm if it determines that a collision will occur; a road shape determination unit that determines whether the other vehicle will cross the travel path of the host vehicle based on the shape of the road in the travel direction of the host vehicle; and an alarm permission determination unit that determines whether to enable the alarm function of the alarm determination unit based on the determination result by the road shape determination unit.

2. A vehicle control device as described in claim 1, wherein the alarm permission determination unit sets the alarm function to enabled when the road shape of the route along which the vehicle is traveling is such that the other vehicle can cross, and sets the alarm function to disabled when the road shape of the route along which the vehicle is traveling is such that the other vehicle cannot cross.

3. A vehicle control device as described in claim 1, further comprising a turn signal detection unit that detects the operating status of the turn signal of the other vehicle, and wherein the warning permission determination unit determines whether to set the warning function of the warning determination unit to enabled based on the road shape and the operating status of the turn signal of the other vehicle.

4. A vehicle control device as described in claim 3, characterized in that the alarm permission determination unit sets the alarm function of the alarm determination unit to permission when the direction indicator of the other vehicle that is not facing the vehicle is not lit.

5. A vehicle control device according to claim 1, characterized in that the alarm determination unit sets the alarm function of the alarm determination unit to on until the alarm-off start point detected by the external environment recognition sensor.

6. A vehicle control device according to claim 1, wherein the warning determination unit changes the type of warning to be output depending on at least one of the acceleration / deceleration and speed of the host vehicle.

7. An alarm control method executed by a vehicle control device, the vehicle control device having an arithmetic unit that executes a program and a storage device accessible by the arithmetic unit, the alarm control method comprising: a crossing vehicle detection procedure that detects another vehicle approaching and crossing a travel path of the host vehicle; an intersection detection procedure that detects an intersection point of the host vehicle and the other vehicle based on predicted movements of the host vehicle and the other vehicle; an alarm judgment procedure that judges whether the host vehicle and the other vehicle will collide at the detected intersection point and issues an alarm if it is determined that a collision will occur; a road shape judgment procedure that judges whether the other vehicle will cross the travel path of the host vehicle based on the shape of the road in the travel direction of the host vehicle; and an alarm permission judgment procedure that judges whether to set the output of an alarm in the alarm judgment procedure to permitted based on the judgment result in the road shape judgment procedure.