Driving assistance device

Abstract

This driving assistance device for preventing a collision between the host vehicle and other vehicles comprises: a host vehicle turning determination unit (21) that determines whether or not the host vehicle is turning; a following determination unit (22) that determines whether or not the host vehicle is following a preceding vehicle traveling in front of the host vehicle among the other vehicles; and a collision determination unit (25) that, when it is determined that the host vehicle is turning and the host vehicle is following the preceding vehicle, relaxes a determination condition regarding whether or not the host vehicle can perform a brake operation in the execution of driving assistance.

Description

Driving assistance devices CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Japanese Patent Application No. 2024-54042, filed on March 28, 2024, the contents of which are incorporated herein by reference.

[0002] The present disclosure relates to a driving assistance device for preventing a collision between a vehicle and another vehicle.

[0003] A conventional driving assistance device of this type is described, for example, in Patent Document 1. The driving assistance device described in Patent Document 1 detects other vehicles present around the subject vehicle, and calculates a first collision prediction time by dividing the relative distance between the subject vehicle and the detected other vehicle by the relative speed, and a second collision prediction time by using the relative distance, the relative speed, and the relative acceleration.

[0004] This driving assistance device determines the possibility of a collision between the vehicle and another vehicle based on two collision prediction times, thereby reducing erroneous determinations that there is a possibility of a collision in situations where there is no possibility of a collision, and improving the accuracy of driving assistance for collision prevention.

[0005] JP 2011-121491 A

[0006] For example, in a driving situation where the radius of curvature of the curve (hereinafter referred to as "curve R") of the driving trajectory of the vehicle becomes small, such as when the vehicle is turning, it may be determined that there is a possibility of a collision. Even in such a driving situation where the curve R becomes small, it is preferable to perform driving assistance to prevent a collision between the vehicle and another vehicle.

[0007] However, the driving assistance device described in Patent Document 1 cannot respond to the above-mentioned situation because it activates a safety device used for driving assistance to prevent a collision when the host vehicle is not swaying and is traveling in a straight section. In other words, conventional driving assistance devices have difficulty actively providing driving assistance to prevent a collision in a situation where there remains a possibility that a collision between the host vehicle and another vehicle can be avoided by steering by the driver of the host vehicle. Hereinafter, for convenience of explanation, the driver's steering to avoid a collision between the host vehicle and an object such as another vehicle will be referred to as "driver's steering avoidance."

[0008] In view of the above, the present disclosure aims to provide a driving assistance device that can actively provide driving assistance to prevent collisions when the driver of the vehicle is unlikely to steer to avoid a collision, even in driving situations other than when the vehicle is traveling in a straight section.

[0009] According to one aspect of the present disclosure, a driving assistance device is a driving assistance device for preventing a collision between a host vehicle and another vehicle, and includes: a host vehicle turning determination unit that determines whether the host vehicle is turning; a following determination unit that determines whether the host vehicle is following a preceding vehicle that is traveling ahead of the host vehicle; and a collision determination unit that, when it is determined that the host vehicle is turning and following the preceding vehicle, relaxes the determination conditions for whether to apply the brakes of the host vehicle when performing driving assistance.

[0010] This driving assistance device uses a host vehicle turning determination unit to determine whether the host vehicle is turning, and a following determination unit to determine whether the host vehicle is following a preceding vehicle located ahead. When the collision determination unit determines that the host vehicle is turning and following a preceding vehicle, the driving assistance device relaxes the determination conditions for whether to apply the brakes of the host vehicle when performing driving assistance. This allows the driving assistance device to actively provide driving assistance to prevent a collision when the driver of the host vehicle is unlikely to steer to avoid a collision.

[0011] 1 is a block diagram showing an example of the configuration of a driving assistance device according to an embodiment; FIG. 2 is a flowchart showing an example of a process for driving assistance to prevent a collision; FIG. 3 is a diagram showing examples of determination items in determining whether a preceding vehicle is turning; FIG. 4 is an explanatory diagram of a determination of a turning of a host vehicle; FIG. 5 is a schematic diagram showing a state in which the host vehicle is turning; FIG. 6 is an explanatory diagram of a prerequisite determination in determining whether the host vehicle is following a preceding vehicle; FIG. 7 is an explanatory diagram of an angular difference between the speed vectors of the host vehicle and the preceding vehicle; FIG. 8 is a diagram showing an example of a driving scene corresponding to a case in which the angular difference between the speed vectors of the host vehicle and the preceding vehicle is equal to or greater than a predetermined value; FIG. 9 is a diagram showing an example of a driving scene corresponding to a case in which the ground speed of the preceding vehicle is equal to or less than a predetermined value and the preceding vehicle is present in the host lane; FIG. 10 is an explanatory diagram of a determination of whether the preceding vehicle is in the host lane; FIG. 11 is an explanatory diagram of a minimum value of a lateral position of a target object relative to a right white line and a maximum value of a lateral position of a target object relative to a left white line; FIG. 12 is an explanatory diagram of a counter determination; FIG. 13 is an explanatory diagram of a counter determination in a first driving scene;

[0012] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. In the following embodiments, identical or equivalent parts will be denoted by the same reference numerals.

[0013] (Embodiment) A driving assistance device 1 according to an embodiment will be described.

[0014] Hereinafter, a vehicle such as an automobile equipped with the driving assistance device 1 will be referred to as the "host vehicle," and the direction along the overall length of the host vehicle, from the passenger compartment toward the windshield, will be referred to as the "forward." Furthermore, the directions along the width of the host vehicle, to the left and right when facing forward, will be referred to as the "left" and "right," respectively, and the direction in which the host vehicle faces when traveling forward will be referred to as the "direction of travel." Furthermore, another vehicle ahead of the host vehicle, traveling in the same lane as the host vehicle, will be referred to as the "preceding vehicle."

[0015] 1, the driving assistance device 1 includes various on-board devices mounted on the host vehicle V1, a collision determination ECU 20, and a safety device 30. ECU is an abbreviation for Electronic Control Unit. The driving assistance device 1 acquires various pieces of information about the host vehicle V1 and the surrounding area from the on-board devices, determines the possibility of a collision between the host vehicle V1 and another vehicle using the collision determination ECU 20, and activates the safety device 30 based on the determination result to control braking and warnings.

[0016] The in-vehicle devices include, for example, an object detection device 10, an imaging device 11, a steering angle sensor 12, a yaw rate sensor 13, a wheel speed sensor 14, and a turn signal 15. The in-vehicle devices are connected to, for example, an in-vehicle LAN and input their respective signals to the collision determination ECU 20. The signals may be input to the collision determination ECU 20 directly or via a vehicle ECU or the like. LAN is an abbreviation for Local Area Network.

[0017] The object detection device 10 transmits, for example, millimeter waves to the outside, receives reflected waves from the surfaces of other objects, such as other vehicles, and detects the object based on signals obtained from the reflected waves, acquiring information about the object's position and relative speed with respect to the host vehicle V1. The object detection device 10 includes, for example, a millimeter-wave radar sensor that transmits millimeter waves and receives the reflected waves, and a radar ECU that calculates the object's position and relative speed based on the reflected wave signals obtained from the reflected waves. The object detection device 10 is configured, for example, with multiple millimeter-wave radar sensors and radar ECUs disposed in front and behind the host vehicle V1, and each radar ECU performs arithmetic processing on the reflected wave signals received by each millimeter-wave radar sensor. The millimeter-wave radar sensor includes, for example, an antenna for transmitting and receiving millimeter waves and a millimeter-wave module for generating millimeter waves. The radar ECU includes, for example, a circuit board mounted with various electronic components, such as a CPU, ROM, RAM, and input / output interface. CPU, ROM, and RAM are abbreviations for Central Processing Unit, Read Only Memory, and Random Access Memory, respectively. For example, the various ECUs described below are basically configured in the same way as the radar ECU, with various electronic components such as a CPU mounted on a circuit board.

[0018] The imaging device 11, for example, captures an image of a predetermined area ahead of the vehicle V1 and analyzes the resulting image data using known image recognition technology to obtain various information such as road markings, road markings, road edges, the status of the blinkers of the preceding vehicle, and the type of object. The imaging device 11 includes, for example, one or more cameras that capture images of the predetermined area and an image processing ECU that performs analysis processing of the resulting images. The imaging device 11 is mounted in any position that allows it to capture an image of the predetermined area ahead of the vehicle V1.

[0019] The steering angle sensor 12 is a known in-vehicle sensor that detects the direction and operation amount of the steering wheel of the host vehicle V1. When the driver performs a steering operation, the steering angle sensor 12 outputs a detection signal corresponding to the steering angle of the steering wheel. The detection signal from the steering angle sensor 12 is used, for example, to calculate the traveling direction of the host vehicle V1.

[0020] The yaw rate sensor 13 is a known in-vehicle sensor that detects the yaw rate acting on the host vehicle V1. The yaw rate sensor 13 outputs a detection signal corresponding to the magnitude of the yaw rate acting on the host vehicle V1, for example.

[0021] The wheel speed sensors 14 are known in-vehicle sensors that detect the rotation of the wheels of the host vehicle V1. The wheel speed sensors 14 are provided, for example, near each of the four wheels of the host vehicle V1 and output detection signals corresponding to the magnitude of the rotation angle of each of the four wheels. The detection signals from the wheel speed sensors 14 are used to calculate the vehicle speed of the host vehicle V1.

[0022] The turn signal 15 is a known blinker that is operated by the driver to inform surroundings of the direction of travel when turning the vehicle V1 right or left. For example, the output signal from the turn signal 15 is used for blinker determination in determining a collision scene, which will be described later.

[0023] The collision determination ECU 20 has, for example, a host vehicle turning determination unit 21, a following determination unit 22, a scene determination unit 23, a preceding vehicle turning determination unit 24, and a collision determination unit 25. The collision determination ECU 20 corresponds to a collision determination device, and determines whether or not there is a possibility of a collision between the host vehicle V1 and another object such as another vehicle, and outputs, for example, a signal according to the determination result to the safety device 30. For example, when the collision determination ECU 20 determines that there is a possibility of a collision between the host vehicle V1 and another object, the collision determination ECU 20 generates and outputs an activation signal for activating the brake ECU 31 and the warning ECU 32, and executes operation control of the safety device 30.

[0024] The host vehicle turning determination unit 21 determines whether the host vehicle V1 is turning and outputs a signal according to the determination result. The host vehicle turning determination unit 21 performs the determination process based on, for example, some of the output signals from the above-mentioned in-vehicle devices, etc. Details of the determination process by the host vehicle turning determination unit 21 will be described later.

[0025] The following determination unit 22 determines whether the host vehicle V1 is traveling following another vehicle present ahead of the host vehicle V1, i.e., a preceding vehicle, and outputs a signal according to the determination result. The following determination unit 22 determines, for example, whether a preceding vehicle is present in the section of the road on which the host vehicle V1 is traveling, and if a preceding vehicle is present, whether the host vehicle V1 is traveling following the preceding vehicle. Details of the determination process by the following determination unit 22 will be described later.

[0026] The scene determination unit 23 performs a determination process to determine what type of driving scene the host vehicle V1 and other objects, particularly the preceding vehicle, correspond to, for example, based on some of the output signals from the above-mentioned in-vehicle devices, etc. The scene determination unit 23 outputs, for example, a determination signal corresponding to the determined driving scene to the collision determination unit 25. Examples of driving scenes determined by the scene determination unit 23 will be described later.

[0027] The preceding vehicle turning determination unit 24 determines whether the preceding vehicle is turning and outputs a signal according to the determination result. The preceding vehicle turning determination unit 24 performs the determination process based on, for example, some of the output signals from the above-mentioned on-board devices, etc. Details of the determination process performed by the preceding vehicle turning determination unit 24 will be described later.

[0028] The collision determination unit 25, for example, determines whether there is a possibility of a collision between the host vehicle V1 and another object. The collision determination unit 25 performs a collision determination using a method appropriate for the driving scene, for example, based on output signals from the host vehicle turning determination unit 21, the following determination unit 22, the scene discrimination unit 23, and the preceding vehicle turning determination unit 24. For example, based on the output signals from the host vehicle turning determination unit 21, etc., if a predetermined condition is met, the collision determination unit 25 performs a collision determination process with relaxed collision determination conditions. Otherwise, the collision determination unit 25 performs a collision determination process without relaxed determination conditions. This enables automatic braking even in situations where automatic braking is restricted in conventional driving assistance devices, thereby enabling proactive driving assistance to prevent collisions. For example, the collision determination unit 25 performs a collision determination when the TTC, obtained by dividing the distance between the host vehicle V1 and a detected object by the relative speed, becomes equal to or less than a predetermined threshold. TTC is an abbreviation for Time To Collision. For example, when the collision determination unit 25 determines that there is a possibility of a collision in the collision determination, it generates an activation signal for the safety device 30 and outputs the activation signal to the safety device 30. The relaxation of the conditions for collision determination by the collision determination unit 25 and the details of the collision determination will be described later.

[0029] The safety device 30 corresponds to, for example, a collision suppression device that suppresses a collision between the host vehicle V1 and another object, and includes a brake ECU 31 and a warning ECU 32. The safety device 30 controls the braking and warning of the host vehicle V1.

[0030] The brake ECU 31 controls the braking force of a brake actuator (not shown) of the host vehicle V1, for example, based on an activation signal output from the collision determination ECU 20. The brake ECU 31 adjusts the deceleration rate of the host vehicle V1 to brake the host vehicle V1 and prevent a collision between the host vehicle V1 and another object. For example, when the collision determination unit 25 determines that there is a possibility of a collision, the brake ECU 31 receives a signal corresponding to a brake operation request or a requested deceleration from the collision determination ECU 20 and performs brake control based on the requested deceleration.

[0031] The warning ECU 32 controls the operation of various warning devices (not shown) of the host vehicle V1, for example, based on an activation signal output from the collision determination ECU 20. The warning ECU 32 activates various warnings using sound, video display, etc., to assist in avoiding a collision between the host vehicle V1 and another object.

[0032] The above is the basic configuration of the driving assistance device 1. The driving assistance device 1 has at least the collision determination ECU 20, and is capable of performing collision determination based on predetermined signals from various on-board devices mounted on the host vehicle V1 and controlling the operation of the safety device 30 in accordance with the determination result, and the types and arrangements of the on-board devices can be changed as appropriate.

[0033] [Example of Collision Prevention Control] Next, an example of the processing operation by the driving assistance device 1 will be described.

[0034] The driving assistance device 1 executes the control flow of FIG. 2 when a predetermined start condition is satisfied, for example, when the ignition of the host vehicle V1 is turned on.

[0035] In step S100, for example, the object detection device 10 detects objects such as other vehicles and obstacles present around, and particularly ahead of, the host vehicle V1. Also, in step S100, for example, if the object detection device 10 detects an object, the object detection device 10 or the imaging device 11 identifies the object and outputs a signal corresponding to the identification result to the collision determination ECU 20. The collision determination ECU 20 receives input of various information, such as information on the type of detected object (e.g., a vehicle, a motorcycle, an obstacle such as a fallen object on the road, or a person), as well as information on white lines on the road recognized by the imaging device 11. Note that, hereinafter, an object detected by the object detection device 10 or recognized by the imaging device 11 may be referred to as a "target."

[0036] In step S101, the collision determination ECU 20 acquires various information from various sensors, such as the steering angle, yaw rate, vehicle speed, and whether or not the turn signal 15 is activated, of the host vehicle V1. The various information acquired in steps S100 and S101 is used in the subsequent determination process.

[0037] In step S102, for example, the host vehicle turning determination unit 21 determines whether the host vehicle V1 is turning and outputs a signal according to the determination result. Then, for example, the collision determination ECU 20 advances the process to step S103 if the determination in step S102 is affirmative, and advances the process to step S104 if the determination in step S102 is negative.

[0038] In step S103, for example, the following determination unit 22 determines whether the host vehicle V1 is following a preceding vehicle and outputs a signal according to the determination result. Then, for example, the collision determination ECU 20 advances the process to step S105 if the determination in step S103 is affirmative, or advances the process to step S104 if the determination in step S103 is negative.

[0039] In step S104, for example, the collision determination unit 25 determines whether the host vehicle V1 will collide with another object and outputs a signal according to the determination result. Then, for example, if the collision determination ECU 20 determines a positive result in step S104, the process proceeds to step S111, and if the collision determination ECU 20 determines a negative result in step S104, the process returns to step S100.

[0040] The collision determination in step S104 corresponds to a situation in which the host vehicle V1 is traveling on a straight section without swaying and is not following a preceding vehicle. For example, in step S104, it is determined whether a collision will occur after a predetermined time has elapsed based on the positional relationship and distance between the host vehicle V1 and the object detected in step S100, information on the traveling direction and vehicle speed of the host vehicle V1, etc. In step S104, for example, if the detected object is another vehicle, the collision determination unit 25 determines whether there is a possibility of a collision with the host vehicle V1 by adding information on the traveling direction and relative speed of the detected object. Note that the collision determination in step S104 is not limited to the above example, and other known methods may be used.

[0041] In step S105, for example, the collision determination unit 25 executes processing to relax the determination conditions for collision determination in order to enable proactive activation of the safety device 30. When the process proceeds to step S105, it is assumed that the host vehicle V1 is turning and following a preceding vehicle, and the driver is unlikely to steer to avoid the collision. Therefore, for example, the collision determination unit 25 executes relaxation processing to lower a predetermined threshold value used for scene determination, which will be described later, in order to enable proactive activation of the safety device 30.

[0042] Examples of thresholds that may be relaxed in step S105 include the overlap ratio, the curve radius, the collision history probability, and the number of FSN fusions. The "overlap ratio" is a value obtained by dividing the difference between the lateral positions of the left or right edge of the host vehicle V1 and the center of a target object when the host vehicle V1 is traveling on the reference road by the overall width of the host vehicle V1. The "collision history probability" is, for example, a collision history in which it is determined that two estimated movement trajectories of the host vehicle V1 and the preceding vehicle intersect, and is a probability obtained by dividing the number of collision history events by a predetermined time period (e.g., one second) in the past. The collision history is set, for example, to increase when it is determined that two estimated movement trajectories of the host vehicle V1 and the preceding vehicle intersect, and decrease when they do not, and is temporarily recorded in a recording medium (not shown) in the collision determination ECU 20. The "number of FSN fusions" is, for example, the number of times that two on-board sensors mounted at different positions on the host vehicle V1 both detect the same object when the two on-board sensors detect objects around the host vehicle V1. This is also referred to as the number of fusion fusions. For example, if the number of FSN combinations is large, the detection state by the dual system on-board sensors continues for a predetermined time or longer, and therefore it is determined that the reliability of the target is high.

[0043] Conventional driving assistance systems restrict the activation of the safety device by setting high thresholds for the overlap ratio, curve R, collision history probability, FSN combination count, and other safety device activation conditions when the host vehicle V1 is turning, because the driver may attempt to steer to avoid the collision. In contrast, the driving assistance system 1 relaxes the activation conditions of the safety device 30 when the host vehicle V1 is following a preceding vehicle, even when the host vehicle V1 is turning. It assumes that the host vehicle V1 is likely to continue following the preceding vehicle and that the driver is unlikely to attempt to steer to avoid the collision. In step S105, for example, the collision determination unit 25 relaxes the activation restrictions of the safety device 30 by lowering thresholds for the overlap ratio, curve R, collision history probability, FSN combination count, and other factors. As a result, in steps S109 and S110 (described later), a collision determination is performed under conditions in which the activation conditions of the safety device 30 are relaxed compared to the collision determination in step S104.

[0044] In the following step S106, for example, the scene determination unit 23 determines what kind of driving scene the host vehicle V1 and the preceding vehicle are in based on signals from various sensors, etc., and outputs a signal according to the determination result to the collision determination unit 25. The determination result in step S106 is used, for example, in the subsequent collision determination process.

[0045] In step S107, for example, the preceding vehicle turning determination unit 24 determines whether the preceding vehicle is turning and outputs a signal corresponding to the determination result to the collision determination unit 25. Then, for example, if the collision determination ECU 20 makes a positive determination in step S107, the process proceeds to step S108, and if the collision determination ECU 20 makes a negative determination in step S107, the process proceeds to step S110. The preceding vehicle turning determination unit 24 determines whether the preceding vehicle is turning, for example, based on the three items shown in FIG. 3 . For example, the preceding vehicle turning determination unit 24 determines whether all three of the following conditions are met: "the host vehicle V1 is turning," "the host vehicle V1 is following the preceding vehicle," and "the ground speed of the preceding vehicle is equal to or greater than a threshold." The ground speed threshold is set to a predetermined value, such as 7 km / h. If all three of the above conditions are met, the preceding vehicle turning determination unit 24 determines that the preceding vehicle is turning; otherwise, it determines that the preceding vehicle is not turning.

[0046] The threshold value of the ground speed of the preceding vehicle in determining whether the preceding vehicle is turning is not limited to the above example and can be changed as appropriate. Furthermore, the "AND" in Figure 3 means that the determination is established if all of the listed determination items or conditions are met. This also applies to Figure 4 and subsequent figures.

[0047] In step S108, for example, the collision determination unit 25 calculates the turning trajectory of the preceding vehicle as a curved estimated movement trajectory based on the position of the preceding vehicle and the relative speed and relative acceleration with respect to the host vehicle V1.

[0048] In the following step S109, for example, the collision determination unit 25 determines whether or not the host vehicle V1 will collide with a turning preceding vehicle, and outputs a signal according to the determination result. Then, for example, if the determination in step S109 is affirmative, the collision determination ECU 20 proceeds to step S111, and if the determination in step S109 is negative, the collision determination ECU 20 returns to step S100. In step S109, for example, as in the method described in Japanese Patent Application Laid-Open No. 2020-8288, the two estimated movement trajectories of the host vehicle V1 and the preceding vehicle are calculated in a solid form of three-dimensional coordinates of vertical position, horizontal position, and time axes, and it is determined whether or not the two estimated movement trajectories intersect.

[0049] In step S110, for example, the collision determination unit 25 determines whether the host vehicle V1 will collide with a preceding vehicle that is not turning, and outputs a signal according to the determination result. Then, for example, if the determination in step S110 is affirmative, the collision determination ECU 20 proceeds to step S111, and if the determination in step S110 is negative, the collision determination ECU 20 returns to step S100. In step S110, for example, similar to step S109, when calculating the estimated trajectories of the host vehicle V1 and the preceding vehicle in three-dimensional coordinates, the preceding vehicle is assumed to move at a constant speed in a straight line, and its estimated trajectory is calculated as a straight line. Then, in step S110, for example, the determination is made based on whether the curved estimated trajectory of the host vehicle V1 intersects with the linear estimated trajectory of the preceding vehicle.

[0050] In step S111, for example, the collision determination ECU 20 generates an activation signal for the safety device 30 and outputs the activation signal to the brake ECU 31 and the warning ECU 32. As a result, the safety device 30 automatically applies the brakes and issues a warning without the driver's operation, alerting the driver and preventing the host vehicle V1 from colliding with another object. In this way, for example, the collision determination ECU 20 executes the process of step S111 when it is determined in any of steps S104, S109, and S110 that there is a possibility of a collision, and then returns the process to step S100. For example, the collision determination ECU 20 repeats the above-described series of processes until a predetermined termination condition, such as the ignition being turned off, is met.

[0051] The above is an example of collision prevention control by the driving assistance device 1. When the situation is such that the driver is unlikely to steer to avoid the collision, the driving assistance device 1 relaxes the conditions for executing the collision determination in step S105, thereby relaxing the conditions for braking and warning activation, and making it possible to proactively activate the safety device 30.

[0052] [Determination of Turning of Vehicle] Next, the turning determination in the vehicle turning determination unit 21 will be described.

[0053] For example, the host vehicle turning determination unit 21 determines that the host vehicle V1 is turning if the set conditions shown in Figure 4 are met, and determines that the host vehicle V1 is not turning if any of the set conditions are not met or at least one of the reset conditions is met.

[0054] 4 means that the determination is made if at least one of the listed determination items or conditions is satisfied. This also applies to FIG. 5 and subsequent figures.

[0055] Specifically, the host vehicle turning determination unit 21 determines whether or not the set conditions are satisfied based on, for example, output signals from the steering angle sensor 12 and the yaw rate sensor 13 and corresponding preset thresholds. The set conditions are set, for example, by four items: (1) the absolute value of the steering angular velocity is equal to or less than a start determination threshold, (2) the absolute value of the turning center curve R1 is less than a start determination threshold, (3) the conditions (1) and (2) continue for a predetermined time or more, and (4) the change in yaw rate for the most recent predetermined time is equal to or less than a predetermined value. For example, but not limited to, the predetermined time for (3) and (4) can be 2 seconds, and the predetermined value of the yaw rate change can be Δ5 deg / s.

[0056] 5 shows the state in which the host vehicle V1 turns around a constant curve R, with the direction of travel of the host vehicle V1 indicated by an arrow and the travel path of the host vehicle V1 indicated by a dashed line. The turning center curve R1 is the radius of curvature (unit: meters) of the arc portion of a virtual circle that is the travel path that the host vehicle V1 traces when turning. Point VC in FIG. 5 is the center of the virtual circle.

[0057] The start determination threshold is determined, for example, when the turning center curve R1 is equal to or smaller than a predetermined value, e.g., R1<1000. The start determination threshold is, for example, preset to a value corresponding to the vehicle speed of the host vehicle V1, with the lower the vehicle speed, the lower the value. When all four of the above conditions (1) to (4) are met, the host vehicle V1 is in a state where the steering angular velocity and the turning center curve R1 in the driver's steering remain small for a predetermined period of time or more, and the yaw rate is stable. Therefore, when the set conditions are met, the host vehicle turning determination unit 21 determines that the host vehicle V1 is in a state where it is tracing a substantially constant curve as shown in FIG. 5, i.e., is turning.

[0058] On the other hand, the reset conditions are set, for example, by three items: (i) the absolute value of the steering angular velocity exceeds a release determination threshold; (ii) the absolute value of the turning center curve R1 exceeds a release determination threshold; and (iii) the host vehicle is determined to be traveling straight. The release determination threshold may be set, for example, to the same value as the start determination threshold, or may be set to a different value. Items (i) and (ii) of the reset conditions are the opposite of items (1) and (2) of the set conditions. Item (iii) corresponds, for example, to a situation where all three conditions are satisfied: the steering angle and steering angular velocity are equal to or less than a threshold, the curve R is equal to or greater than a threshold, and the integrated value of the yaw rate is equal to or less than a threshold. The turning determination conditions in the host vehicle turning determination unit 21 are set in advance and, for example, recorded in a recording medium (not shown) of the collision determination ECU 20.

[0059] [Determination of whether to follow a preceding vehicle] Next, the determination of whether to follow in the following determination unit 22 will be described.

[0060] The following determination unit 22 determines whether the host vehicle V1 is following a preceding vehicle, for example, based on a plurality of preset items. Specifically, for example, the following determination unit 22 performs the following determination of the preceding vehicle in two stages: a prerequisite determination and a counter determination. If a counter value in the counter determination (described later) is equal to or greater than a threshold, the following determination unit 22 determines that the host vehicle V1 is following the preceding vehicle. Also, for example, if the counter value in the counter determination is less than the threshold, the following determination unit 22 determines that the host vehicle V1 is not following the preceding vehicle.

[0061] 1: Precondition Determination The precondition determination is a determination as to whether two setting items are satisfied, as shown in FIG. 6 , for example. The first setting item is “the type of detected object is a preceding vehicle or a motorcycle.” The second setting item is “the absolute value of the angular difference between the velocity vectors of the host vehicle V1 and a preceding vehicle traveling at a predetermined speed or higher is less than a threshold” or “a preceding vehicle traveling at a predetermined speed or lower is in the lane of the host vehicle V1.” The threshold for the absolute value of the angular difference in the second setting item is, for example, but not limited to, 30 degrees or less. A positive determination in the precondition determination indicates a situation in which the host vehicle V1 is likely to collide with the preceding vehicle, and a negative determination in the precondition determination indicates a situation in which the possibility of the host vehicle V1 colliding with the preceding vehicle is low and the safety device 30 is not actively activated.

[0062] Here, the angular difference (unit: deg) of the velocity vectors is, for example, as shown in FIG. 7, the angular difference between the host vehicle V1 and the preceding vehicle V2 when viewed from above in the direction opposite to the vertical direction, the corrected velocity vector V Ａ１ and the velocity vector V of the preceding vehicle V2 Ｂ Although FIG. 7 shows a representative example in which the preceding vehicle V2 is a four-wheeled vehicle, the same applies to a two-wheeled vehicle.

[0063] Specifically, as shown in Fig. 7, when the host vehicle V1 is following the turning preceding vehicle V2, it is assumed that the vehicles V1 and V2 are each rotating around an axis of point P1. An imaginary plane when the vehicles V1 and V2 are viewed from above is defined as an xy plane, and an angle θ is defined on the xy plane between a first imaginary line VL1 connecting the center of the host vehicle V1 to point P1 and a second imaginary line VL2 connecting point P2, the center of the preceding vehicle V2, to point P1. In this case, the arc portion obtained by rotating the first imaginary line VL1 by angle θ around the axis of point P1 corresponds to the curve R of the host vehicle V1. The corrected velocity vector V of the host vehicle V1 Ａ１ is a velocity vector when the host vehicle V1 is moved in a circular motion around the point P1 as an axis so as to be on the second virtual straight line VL2 or its extension. Ａ１ is the velocity vector of the vehicle V1 at its current position. Ａ０ As a result, the velocity vector V Ａ０is obtained by applying the correction of the curve R of the angle θ to the above.

[0064] In addition, the velocity vector V Ａ０ , V Ａ１ These vectors are tangent to the circumference of a virtual circle whose center is the point P1 and whose radius is the length of the first virtual straight line VL1. Ｂ is a vector that points in the tangent direction of the circumference of a virtual circle whose center is the point P1 and whose radius is the length of the second virtual line VL2. In FIG. 7, the host vehicle V1 is turned by the angle θ so that the host vehicle V1 is on the extension line of the second virtual line VL2, and the velocity vector V Ａ１ is indicated by a dashed line, and the estimated movement trajectory of the host vehicle V1 is indicated by a two-dot chain line.

[0065] Here, the coordinates of point P1 are (x ｃｅｎ , y ｃｅｎ ), and the coordinates of point P2 are (x ｏｂｊ , y ｏｂｊ ) and the angle θ is defined as positive when the estimated movement trajectory of the vehicle V1, i.e., the direction from the vehicle V1 to the preceding vehicle V2 along the curve R, is counterclockwise, and negative when the opposite is true. In this case, the angle θ is calculated, for example, by the following equation (1) when the curve R of the vehicle V1 is negative, and by the following equation (2) when the curve R is positive and equal to or greater than 0.

[0066] Then, for example, the following determination unit 22 calculates the corrected velocity vector V of the host vehicle V1. Ａ１ and the velocity vector V of the preceding vehicle V2 whose ground speed is equal to or greater than a threshold value (e.g., 7 km / h). Ｂ If the absolute value of the angular difference between the velocity vector V and the velocity vector V is less than a threshold value (for example, 30 degrees), the precondition determination is affirmative. Ａ１ , V Ｂ A case where the absolute value of the angle difference is equal to or greater than the threshold value is, for example, a situation where the preceding vehicle V2 is traveling toward a different road from the host vehicle V1, as shown in FIG.

[0067] The angle θ may be calculated using the arctan2 function (also referred to as the atan2 function), which calculates the angle between the direction of a vector and the x-axis using coordinates, and the calculation method may be changed as appropriate. For example, when the arctan2 function is used to calculate the angle θ, if the curve R of the host vehicle V1 is positive, the quadrant of the xy plane of the virtual plane may be inverted, and calculation processing may be performed using the arctan2(y, x) function.

[0068] On the other hand, when the ground speed of the preceding vehicle V2 is less than the threshold, for example, the following determination unit 22 does not execute the process of calculating the angular difference between the velocity vectors of the vehicles V1 and V2, but executes the determination of whether the preceding vehicle V2 is located on the lane in which the host vehicle V1 is located. When it is determined that the ground speed of the preceding vehicle V2 is less than the threshold and the preceding vehicle V2 is located on the lane in which the host vehicle V1 is located, the host vehicle V1 is in a situation in which it is trying to catch up with the preceding vehicle V2 that is traveling slowly, as shown in Fig. 9. An example of such a situation is catching up with a preceding vehicle on a congested road, and it is assumed that the possibility of the driver taking evasive action by steering is low.

[0069] Hereinafter, for convenience of explanation, the lane on the road in which the host vehicle V1 is located, i.e., the area of ​​the traffic lane, will be referred to as "inside the host vehicle lane," and the determination of whether an object is within the host vehicle lane will be referred to as "determination of whether the object is within the host vehicle lane." For example, "inside the host vehicle lane" means an area in front of the host vehicle V1 that is sandwiched between two dividing lines on the left and right of the lane in which the host vehicle V1 is traveling, or an area that is sandwiched between one of the dividing lines on the left and right of the lane and the road edge on the opposite side of the host vehicle V1. For example, if the imaging device 11 recognizes two white lines on the left and right in front of the host vehicle V1, the area between these white lines will be within the host vehicle lane. Also, for example, if the imaging device 11 recognizes a white line located on either the left or right side in front of the host vehicle V1 and a road edge located opposite the white line, the area between the white line and the road edge will be within the host vehicle lane.

[0070] For example, as shown in Figure 10, one of the determination items for determining whether the vehicle is within the own lane is whether the first condition, "the minimum value of the lateral position of the target on the right white line is less than 0 and the maximum value of the lateral position of the target on the left white line is greater than 0," is met.

[0071] Here, the minimum value of the right white line lateral position and the maximum value of the left white line lateral position of the target will be described. When the target is a preceding vehicle V2, for example, the following determination unit 22 calculates the minimum value V Ｒｍｉｎ and the maximum value of the lateral position of the left white line V Ｌｍａｘ The minimum value of the lateral position of the right white line V Ｒｍｉｎ The white line WL on the road located on the right side of the lane of the vehicle V1 is defined as the right white line RL, and the point on the left edge of the preceding vehicle V2 as seen from the vehicle V1 is defined as point P Ｌ From the right white line RL to point P Ｌ The maximum value of the lateral position of the left white line V Ｌｍａｘ The white line WL located on the left side of the lane of the road on which the vehicle V1 is traveling is defined as the left white line LL, and the point on the right edge of the preceding vehicle V2 as seen from the vehicle V1 is defined as point P Ｒ From the left white line LL to point P Ｒ In this case, for example, a position on the right side of the reference white line WL as viewed from the host vehicle V1 is defined as positive, and a position on the left side is defined as negative.

[0072] In addition, the white lines WL, RL, LL and point P Ｌ , P Ｒ is obtained by capturing an image of the area in front of the vehicle V1 using the imaging device 11 and analyzing the image data obtained using a known image recognition technique. For example, the point P Ｌ , P Ｒ When the preceding vehicle V2 is regarded as a quadrilateral object, the points are defined as the leftmost point and the rightmost point of the four corners of the quadrilateral.

[0073] When the first condition is met, at least the leftmost portion of the preceding vehicle V2 is located to the left of the right white line RL, and the rightmost portion is located to the right of the left white line LL.

[0074] In the in-lane determination, for example, in addition to the first condition, it is determined whether or not a second or third condition is satisfied, as shown in FIG. 10. The second condition is, for example, whether "the target side white line is to the right" and "the minimum value V Ｒｍｉｎ"The trust state of V is valid" or "The minimum value V Ｒｍｉｎ The third condition is set based on whether the following conditions are satisfied: the confidence state of the vehicle is extrapolated, the extrapolation duration is equal to or less than a threshold, and the previous own lane width is usable. The threshold for the extrapolation duration is set to, for example, but not limited to, 2 seconds. This threshold can also be set for the third condition.

[0075] "The target side white line is to the right" means that the target is located closer to the right white line RL than to the left white line LL. Ｒｍｉｎ The term "valid reliability state of the recognized right white line RL" means, for example, that the length of the recognized right white line RL is equal to or longer than a predetermined value, and the reliability of the recognized right white line RL is high. Ｒｍｉｎ The "extrapolation duration is less than a threshold" means, for example, a state in which the right white line RL is recognized but its length is less than a predetermined value, the reliability is medium, and the lack of the white line needs to be compensated for by extrapolating from the recognized right white line RL. Ｒｍｉｎ "Past own lane width is usable" means that the width of the lane in which the own vehicle V1 is traveling, recognized and acquired through the most recent image capture, is taken as the own lane width W, and information on the own lane width W can be used. Note that the own lane width W refers to, for example, the width of an imaginary line that intersects the left white line LL and the right white line RL of the lane in which the own vehicle V1 is traveling and connects these white lines.

[0076] The third condition is, for example, "the target side white line direction is to the left" and "the maximum value V Ｌｍａｘ "The trust state of V is valid" or "The maximum value V Ｌｍａｘ The reliability state of the vehicle is extrapolated, the extrapolation duration is less than a threshold, and the previous lane width is usable. Ｌｍａｘ "The trust state of is valid," "The maximum value V Ｌｍａｘ The "extrapolation trust state is extrapolated" basically means the same as above, and the left and right of the white line are reversed. Ｌｍａｘ "The previous lane width is usable" has the same meaning as above.

[0077] For example, in the in-lane determination, the following determination unit 22 determines that the preceding vehicle V2 is in the own lane if the first condition and the second or third condition are met, and otherwise determines that the preceding vehicle V2 is not in the own lane.

[0078] The above is an overview of the precondition determination. For ease of explanation, a positive determination in the precondition determination will be referred to as "the precondition is met," and a negative determination in the precondition determination will be referred to as "the precondition is not met."

[0079] 2: Counter Determination In the counter determination, as shown in FIG. 12 , for example, a counter is increased or decreased based on six items: overlap ratio determination, current lane determination, blinker determination, counter maintenance determination, counter decrement determination, and counter reset determination, and the presence or absence of a preceding vehicle is determined based on the counter value. In the counter determination, the counter value is increased based on three items: overlap ratio determination, current lane determination, and blinker determination, the counter value is maintained based on the counter maintenance determination, and the counter value is decremented based on the counter decrement determination. In the counter determination, the counter value is reset to a predetermined value such as 0 based on the counter reset determination. The counter value is set, for example, within a predetermined range (e.g., 0 to 20). In the counter determination, if the counter value exceeds a threshold, it is determined that the target is a preceding vehicle, i.e., that a preceding vehicle is present.

[0080] The overlap ratio determination is an index for determining the degree to which a target ahead overlaps with the host vehicle V1. The overlap ratio determination is performed, for example, based on whether "preconditions are met" and "the overlap ratio of the target is equal to or greater than a threshold value." The threshold for the overlap ratio determination is set to, for example, but not limited to, 45%. The overlap ratio determination is performed, for example, by setting a counter increment value to a predetermined value (e.g., +1) and at predetermined intervals (e.g., 50 msec). For example, the ON threshold for the overlap ratio determination is set to a predetermined value α. The following determination unit 22 determines that the preceding vehicle V2 is present when the counter value exceeds α, and determines that the preceding vehicle V2 is not present when the counter value is less than the OFF threshold. The OFF threshold is set to a value equal to or less than the ON threshold and may be the same value as the ON threshold or a different value.

[0081] The in-lane determination is an index for determining whether or not a target object is in the current lane. In the counter determination, for example, the increment value of the counter in the in-lane determination is set to a predetermined value (e.g., +1), and the determination is performed at predetermined intervals (e.g., 50 msec). The counter in the in-lane determination is set to increment when, for example, "prerequisites are met" and "a positive determination is made in the in-lane determination" is satisfied. In the counter determination, for example, the ON threshold for the in-lane determination is set to a predetermined value β. In this case, the following determination unit 22 determines that a preceding vehicle V2 is present when the counter in the in-lane determination exceeds β. An OFF threshold that is equal to or lower than the ON threshold is also set for the in-lane determination in the counter determination.

[0082] The turn signal determination is an index for determining whether the host vehicle V1 and the preceding vehicle V2 are changing course in the same direction. The turn signal determination is, for example, a determination of whether a first condition, "the precondition is met," and either a second condition, "the host vehicle V1 and the preceding vehicle V2 activate their turn signals for a left turn" or "the host vehicle V1 and the preceding vehicle V2 activate their turn signals for a right turn," are met. The turn signal determination is performed, for example, by setting a predetermined value (e.g., +1) as the increment value of a counter when the above two conditions are met, and at predetermined intervals (e.g., 50 msec). For example, the ON threshold for the turn signal determination is set to a predetermined value γ. The following determination unit 22 determines that the preceding vehicle V2 is present when the counter value exceeds γ, and determines that the preceding vehicle V2 is not present when the counter value is less than the OFF threshold.

[0083] The second condition for the turn signal determination is determined based on, for example, the signal of the turn signal 15 of the host vehicle V1 and information on the operating status of the turn signal of the preceding vehicle V2 recognized by the imaging device 11. The above-mentioned α, β, and γ are predetermined values ​​within the setting range of the counter, and some or all of them may be the same or different and are set as appropriate.

[0084] For ease of explanation, the determination item for determining whether the precondition is met may be referred to as (A), the determination item for determining whether the overlap ratio is equal to or greater than a predetermined value may be referred to as (B), and similarly, the determination item for determining whether a preceding vehicle is present in the vehicle's own lane may be referred to as (C), and the determination item for the second condition in the turn signal determination may be referred to as (D).

[0085] The counter maintenance determination is a determination as to whether or not to maintain the counter value. The counter maintenance determination is made, for example, based on whether or not the conditions "precondition is not met" and "(C) or (D) is met" are met. For example, if the counter maintenance determination is positive, the tracking determination unit 22 maintains the current counter value, and if not, increases or decreases the counter value.

[0086] The counter decrement determination is a determination as to whether or not to decrement the counter value. The counter decrement determination is performed, for example, based on whether or not all of (A), (B), (C), and (D) are true. For example, if the counter decrement determination is true, the tracking determination unit 22 decrements the counter value by a predetermined value (for example, -1), and if not, the tracking determination unit 22 increments or maintains the counter value.

[0087] The counter reset determination is a determination as to whether or not to reset the counter value to a predetermined value (for example, an initial value such as 0). The counter reset determination is performed, for example, based on whether or not a target object information reset flag is set. The target object information reset flag is set, for example, when the object detection device 10 or the like does not detect an object in the area ahead of the host vehicle V1, or when an object with a possibility of collision is detected in the area but a different object is newly detected in place of the object.

[0088] The counter maintenance determination, counter decrement determination, and counter reset determination are performed at predetermined intervals (for example, 50 msec) in the same manner as the overlap rate determination, in-lane determination, and turn signal determination.

[0089] 3: Specific Examples of Counter Judgment Next, specific examples of counter judgment for each driving scene will be described.

[0090] 3-1: First Driving Scene First, a first driving scene will be described in which the host vehicle V1 is driving along a curved road with a white line WL and following a preceding vehicle V2, as shown in FIG.

[0091] Note that the numbers "1," "2," and "3" in the first row of FIG. 13 indicate the chronological order of the driving scenes. Hereinafter, for ease of explanation, the driving scenes 1, 2, and 3 will be referred to as the "first scene," "second scene," and "third scene." Furthermore, a "◯" in each of the columns for the prerequisite, overlap ratio, and turn signal determination indicates that the determination is established (positive determination), and an "X" indicates that the determination is not established (negative determination). This also applies to the following FIGS. 14 to 17. Hereinafter, for ease of explanation, the four counter determinations, namely the prerequisite determination, overlap ratio determination, in-lane determination, and turn signal determination, will be collectively referred to as the "four determinations."

[0092] In the first scene of the first driving scene, the host vehicle V1 is traveling straight together with the preceding vehicle V2, and the preceding vehicle V2 is in the host vehicle's own lane, so the prerequisite determination, overlap ratio determination, and in-lane determination are all evaluated as ◯. On the other hand, the host vehicle V1 and the preceding vehicle V2 are not operating their turn signals, so the turn signal determination is evaluated as ×. Therefore, in the first scene, the overlap ratio determination and in-lane determination are both satisfied, and the counters are incremented by the amounts of these two determinations.

[0093] In the second scene of the first driving scene, the host vehicle V1 is still traveling straight, while the preceding vehicle V2 is turning along a curve in the road, and neither the host vehicle V1 nor the preceding vehicle V2 is activating its turn signal. Therefore, in the second scene, only the in-lane determination is marked as OK, and the prerequisite determination, overlap ratio determination, and turn signal determination are marked as ×. Furthermore, in the counter determination, the counter value is increased when the prerequisite condition is met, but because the counter maintenance determination is met, the counter value is maintained unchanged in the second scene.

[0094] In the third scene of the first driving scene, the host vehicle V1 is turning along a curve in the road, while the preceding vehicle V2 has passed the curve and is proceeding straight, with neither the host vehicle V1 nor the preceding vehicle V2 activating their turn signals. Therefore, in the third scene, the prerequisite determination, the overlap ratio determination, and the in-lane determination are all evaluated as ◯, and the turn signal determination is evaluated as ×. Therefore, in the third scene, the counters are incremented by the overlap ratio determination and the in-lane determination.

[0095] The first driving scene is a situation in which the preceding vehicle V2 is continuously determined to be in its own lane before and after the turning of the host vehicle V1. For example, when it is determined that the host vehicle V1 is turning and the determination that the preceding vehicle V2 is in its own lane continues to be "o" before and after the turning, the scene determination unit 23 determines that the driving scene is the first driving scene.

[0096] 3-2: Second Driving Scene Next, we will explain the second driving scene, in which the host vehicle V1 travels along a curved road with a white line WL and passes by another vehicle V3 parked outside the white line WL, as shown in Figure 14, for example.

[0097] In the first scene of the second driving scene, although another vehicle V3 is ahead of the host vehicle V1, the other vehicle V3 is not in the host vehicle's lane, so the prerequisite determination and the overlap ratio determination are ◯, and the in-host vehicle's lane determination is ×. Furthermore, because neither the host vehicle V1 nor the other vehicle V3 has its turn signal activated, the turn signal determination is ×. Therefore, in the first scene, the change value of the counter increases by the amount of the overlap ratio determination.

[0098] The second scene in the second driving scene is the same as the first scene except that the distance between the vehicle V1 and the other vehicle V3 is shorter, so the change value of the counter increases by the amount of the overlap ratio determination.

[0099] In the third scene of the second driving scene, the host vehicle V1 passes by the other vehicle V3 and there is no other vehicle V3 ahead, so all four judgments are ×. In other words, in the third scene, all of (A) to (D) are not established, and the counter decrement judgment is established, so the counter is decremented by the amount of the counter decrement judgment.

[0100] The second driving scene is a situation in which the prerequisite and overlap ratio determinations are discontinued after the host vehicle V1 turns. For this reason, for example, when it is determined that the host vehicle V1 will turn, the scene determination unit 23 determines that the driving scene is the second driving scene if the prerequisite and overlap ratio determinations are "OK" before the turn and then "X" after the turn.

[0101] 3-3: Third Driving Scene Next, a third driving scene will be described in which the host vehicle V1 turns right or left in the same direction as the preceding vehicle V2 at an intersection with a white line WL, as shown in FIG.

[0102] In the first scene of the third driving scene, the host vehicle V1 is traveling following the preceding vehicle V2, and both the host vehicle V1 and the preceding vehicle V2 have their blinkers on in the same direction, so all four judgments are YES. Therefore, in the first scene, the overlap ratio judgment, the in-lane judgment, and the blinker judgment are all successful, and the counter is incremented by the amount of these three judgments.

[0103] In the second scene of the third driving scene, the host vehicle V1 is about to enter an intersection, but the preceding vehicle V2 is turning within the intersection, so only the blinker judgment is "Yes." However, because the prerequisite judgment is "No," the counter maintenance judgment is satisfied, and the counter is maintained without changing in the second scene.

[0104] In the third scene of the third driving scene, the host vehicle V1 turns within the intersection, while the preceding vehicle V2 has completed a right or left turn and its turn signal is off, so the prerequisite determination and the overlap ratio determination are ◯, and the vehicle in the host lane determination and the turn signal determination are ×. Therefore, in the third scene, the counter is incremented by the overlap ratio determination.

[0105] The third driving scene is a situation in which the turn signal determination is continuous while the host vehicle V1 is turning. Therefore, for example, when it is determined that the host vehicle V1 is turning, if the turn signal determination is “o” during the turn, the scene determination unit 23 determines that the driving scene is the third driving scene.

[0106] 3-4: Fourth Driving Scene Next, a fourth driving scene will be described in which, as shown in FIG. 16, only the preceding vehicle V2 that the host vehicle V1 is following turns right or left, while the host vehicle V1 continues to go straight.

[0107] In the first scene of the fourth driving scene, the host vehicle V1 is traveling following the preceding vehicle V2, and only the preceding vehicle V2 has its turn signal on, so the prerequisite determination, overlap ratio determination, and in-lane determination are all evaluated as ◯, and the turn signal determination is evaluated as ×. Therefore, in the first scene, the counter is incremented by the amount by which the overlap ratio determination and in-lane determination are satisfied.

[0108] In the second scene of the fourth driving scene, the host vehicle V1 is about to enter an intersection, while the preceding vehicle V2 is turning within the intersection and only the preceding vehicle V2 is operating its blinker, so all four judgments are ×. Therefore, in the second scene, the counter decrement judgment is established, and the counter is decremented by the amount that the judgment is established.

[0109] In the third scene of the fourth driving scene, the host vehicle V1 is traveling straight through the intersection, and the preceding vehicle V2 has completed a right or left turn and its blinker is off, so all four judgments are ×, just like in the second scene. Therefore, in the third scene, the counter decrement judgment is true, and the counter is decremented by the amount that this judgment is true.

[0110] The fourth driving scene is a situation in which the host vehicle V1 does not turn and all four judgments are discontinued after the preceding vehicle V2 turns right or left. For this reason, for example, if the host vehicle V1 is not judged to turn and the prerequisite judgment, overlap ratio judgment, and in-lane judgment are "OK" before passing through the intersection, and these three judgments are "NO" after passing through the intersection, the scene judgment unit 23 judges that the driving scene is the fourth driving scene.

[0111] 3-5: Fifth Driving Scene Next, we will explain the fifth driving scene, as shown in Figure 17, in which the preceding vehicle V2 being followed by the host vehicle V1 goes straight through an intersection and the host vehicle V1 turns right or left at the intersection.

[0112] In the first scene of the fifth driving scene, the host vehicle V1 is traveling following the preceding vehicle V2, and only the host vehicle V1 has its turn signal on, so the prerequisite determination, overlap ratio determination, and in-lane determination are all evaluated as ◯, and the turn signal determination is evaluated as ×. Therefore, in the first scene, the counter is incremented by the amount that the overlap ratio determination and in-lane determination are satisfied.

[0113] In the second scene of the fifth driving scene, the host vehicle V1 is about to enter an intersection, while the preceding vehicle V2 is traveling straight through the intersection, and only the host vehicle V1 has its turn signal on. Therefore, the prerequisite condition determination and the overlap ratio determination are "OK," and the host vehicle is in its own lane determination and the turn signal determination are "X." Therefore, the score for the second scene increases by the amount of the overlap ratio determination.

[0114] In the third scene of the fifth driving scene, the host vehicle V1 has completed a right or left turn at an intersection, the blinker is turned off, and there is no preceding vehicle V2 ahead, so all four judgments are ×. Therefore, in the third scene, the counter decrement judgment is established, and the counter is decremented by the amount that the judgment was established.

[0115] The fifth driving scene is a situation in which the prerequisite and overlap ratio determinations are discontinued after the host vehicle V1 turns. For this reason, for example, when it is determined that the host vehicle V1 will turn, the scene determination unit 23 determines that the driving scene is the fifth driving scene if the prerequisite and overlap ratio determinations are "OK" before the turn and these two determinations are "NG" after the turn.

[0116] According to this embodiment, when the host vehicle turning determination unit 21 and the following determination unit 22 determine that the host vehicle V1 is turning and following a preceding vehicle, the collision determination unit 25 relaxes the thresholds of various conditions in the collision determination related to whether or not to activate the safety device 30. This enables the driving assistance device 1 to actively provide driving assistance to prevent a collision when the driver of the host vehicle V1 is unlikely to steer to avoid a collision.

[0117] (Other Embodiments) While the present disclosure has been described with reference to examples, it is understood that the present disclosure is not limited to those examples or structures. The present disclosure also encompasses various modifications and modifications within the scope of equivalents. In addition, various combinations and forms, as well as other combinations and forms including only one element, more than one, or less than one, are also within the scope and spirit of the present disclosure.

[0118] The control unit (e.g., collision determination ECU 20) and the method thereof described in the present disclosure may be implemented by a special-purpose computer configured by configuring a processor and memory programmed to execute one or more functions embodied in a computer program. Alternatively, the control unit and the method thereof described in the present disclosure may be implemented by a special-purpose computer configured by configuring a processor with one or more dedicated hardware logic circuits. Alternatively, the control unit and the method thereof described in the present disclosure may be implemented by one or more special-purpose computers configured by combining a processor and memory programmed to execute one or more functions with a processor configured with one or more hardware logic circuits. Furthermore, the computer program may be stored as instructions executed by a computer on a computer-readable non-transitory tangible recording medium.

[0119] It goes without saying that in each of the above embodiments, the elements constituting the embodiments are not necessarily essential unless they are specifically stated as essential or are clearly considered essential in principle. Furthermore, in each of the above embodiments, when numerical values ​​such as the number, values, amounts, and ranges of the components of the embodiments are mentioned, they are not limited to the specific numbers unless they are specifically stated as essential or are clearly limited to a specific number in principle. Furthermore, in each of the above embodiments, when the shapes, positional relationships, etc. of the components are mentioned, they are not limited to the shapes, positional relationships, etc., unless they are specifically stated or are clearly limited to a specific shape, positional relationship, etc. in principle.

Claims

1. A driving assistance device for preventing a collision between a host vehicle and another vehicle, comprising: a host vehicle turning determination unit (21) that determines whether the host vehicle is turning; a following determination unit (22) that determines whether the host vehicle is following a preceding vehicle that is traveling ahead of the host vehicle; and a collision determination unit (25) that relaxes the determination conditions for whether to apply the brakes of the host vehicle when performing driving assistance when it is determined that the host vehicle is turning and following the preceding vehicle.

2. The following determination unit determines, in an imaginary plane when the host vehicle and the preceding vehicle are viewed from above in the direction opposite to the vertical direction, a virtual line (VL1) connecting the turning center (P1) of the host vehicle and the host vehicle as a first virtual line, a virtual line (VL2) connecting the turning center and the preceding vehicle as a second virtual line, an angle between the first virtual line and the second virtual line as θ, and a velocity vector (V Ａ０ ) by θ toward the preceding vehicle, and the velocity vector obtained is the corrected velocity vector (V Ａ１ ) as the corrected velocity vector and the velocity vector (V Ｂ 2. The driving assistance device according to claim 1, wherein when an absolute value of an angle difference between the subject vehicle and the preceding vehicle is equal to or smaller than a predetermined value, it is determined that the subject vehicle satisfies a precondition for following the preceding vehicle.

3. The driving assistance device described in claim 1, wherein the following determination unit acquires information on the outline of the preceding vehicle and information on the lane markings (WL) on which the subject vehicle is traveling from on-board equipment (10, 11) mounted on the subject vehicle, and determines whether the preceding vehicle is in the traveling lane based on information on the distance from the left white line to the rightmost part of the preceding vehicle and the distance from the right white line to the leftmost part of the preceding vehicle, regarding the white line located on the left side of the traveling lane of the subject vehicle as a left white line (LL) and the white line located on the right side as a right white line (RL).

Images