Collision determination device

Abstract

To improve the accuracy of collision determination when an object is turning, in a collision determination device for executing collision determination based on movement estimated-routes of the own vehicle and the object.SOLUTION: A collision determination device calculates an own vehicle estimated-route PA1 which is a movement estimated-route of an own vehicle and an object estimated-route PA2 which is a movement estimated-route of an object, in a three-dimensional coordinates system defined by a distance X in a vehicle width direction of the own vehicle, a distance Y in a traveling direction, and an elapsed time T from the present. When the detected object is a preceding vehicle and the own vehicle is turning and following the preceding vehicle, the collision determination device calculates the object estimated-route PA2 in a curved shape, as a turning trajectory around the turning center coordinates of the own vehicle.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a collision determination device for preventing a collision between a vehicle and another object. [Background technology]

[0002] Conventionally, an example of this type of collision determination device is that described in Patent Document 1. The collision determination device described in Patent Document 1 expresses an estimated movement path of the subject vehicle and a detected object in three-dimensional coordinates based on three axes: distance in the direction of travel of the subject vehicle, distance in the vehicle width direction, and elapsed time from the present, based on various information acquired from on-board devices of the subject vehicle.

[0003] This collision determination device expresses the estimated movement paths of the vehicle and the object using the above-mentioned three-dimensional coordinates, and determines the possibility of a collision based on whether or not an intersection exists between these two paths, thereby enabling appropriate collision determination that takes the passage of time into consideration. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-8288 Summary of the Invention [Problem to be solved by the invention]

[0005] Through careful investigation by the inventors, it was found that in the above-mentioned collision determination device, when a detected object is moving at a constant speed in a straight line, the estimated path of movement coincides with the actual path of movement, but when the object is moving in a turning motion, the estimated path of movement deviates from the actual path of movement.

[0006] In view of the above, the present disclosure aims to provide a collision detection device that reduces the deviation between an estimated movement path and an actual movement path when a detected object is making a turning movement, thereby improving the accuracy of collision detection. [Means for solving the problem]

[0007] According to one aspect of the present disclosure, a collision determination device is a collision determination device that determines whether or not a collision occurs between a host vehicle (V1) and an object detected by an object detection device (10), a vehicle path calculation unit (21) that calculates an estimated path of movement of the vehicle in a three-dimensional coordinate system defined by a distance in a traveling direction of the vehicle, a distance in a width direction of the vehicle, and an elapsed time from the present; an object path calculation unit (22) that calculates an estimated movement path of the object in a three-dimensional coordinate system based on the position of the object; a collision determination unit (25) that determines whether or not there is a collision between the host vehicle and the object based on whether or not there is an intersection between the host vehicle's estimated movement path and the object's estimated movement path; When the object is a preceding vehicle and the host vehicle is following the object while turning, the object path calculation unit calculates an estimated movement path of the object as a turning trajectory centered on the turning center coordinates of the host vehicle.

[0008] This collision determination device calculates an estimated movement path of the host vehicle and an estimated movement path of the detected object in a three-dimensional coordinate system defined by the distance in the traveling direction of the host vehicle, the distance in the vehicle width direction of the host vehicle, and the elapsed time from the present. This collision determination device determines the possibility of a collision between the host vehicle and the object based on the presence or absence of an intersection between the two estimated movement paths of the host vehicle and the object. When the object is a preceding vehicle and the host vehicle is following the object while turning, this collision determination device calculates the estimated movement path of the object as a turning trajectory centered on the turning center coordinates of the host vehicle. As a result, when the detected object is turning, the estimated movement path is estimated to be curved, reducing the deviation between the estimated movement path of the object and the actual path, resulting in a collision determination device with improved collision determination accuracy.

[0009] The reference symbols in parentheses attached to each component indicate an example of the correspondence between the component and the specific components described in the embodiments described below. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a block diagram illustrating an example of the configuration of a driving assistance device according to an embodiment. [Figure 2] FIG. 2 is a schematic diagram showing an example of a calculated estimated movement path of the host vehicle and an object; [Figure 3] 10 is a flowchart illustrating an example of a process for driving assistance to prevent a collision. [Figure 4] 10 is a flowchart showing an example of a process for determining whether to turn and follow a preceding vehicle; [Figure 5] FIG. 10 is an explanatory diagram of a turning determination of the host vehicle. [Figure 6] FIG. 10 is a schematic diagram showing a situation in which an object exists on the vehicle trajectory. [Figure 7] FIG. 10 is a schematic diagram showing an example of determining whether an object exists on the vehicle trajectory; [Figure 8] FIG. 10 is an explanatory diagram illustrating calculation of the lateral position of an object relative to the vehicle trajectory. [Figure 9] FIG. 10 is an explanatory diagram of preconditions for follow-up determination. [Figure 10] FIG. 10 is an explanatory diagram illustrating a comparison between a future velocity vector of a host vehicle and a velocity vector of an object. [Figure 11] 1 is a schematic diagram showing an example of a driving scene corresponding to a case where the angular difference between the velocity vectors of the host vehicle and an object is equal to or greater than a predetermined value; [Figure 12] 1 is a schematic diagram showing an example of a driving scene in which the ground speed of a preceding vehicle is equal to or less than a predetermined value and the preceding vehicle is present within the same white line; [Figure 13] 10 is a schematic diagram showing an example of a comparison of estimated movement paths of the host vehicle and an object in a two-dimensional coordinate system formed by distances in the traveling direction and distances in the vehicle width direction; FIG. [Figure 14] 14 is a schematic diagram showing the comparison result between the estimated movement path of the host vehicle in a three-dimensional coordinate system and the estimated movement path of the object calculated as uniform linear motion in the example of FIG. 13. FIG. [Figure 15] 10 is an explanatory diagram illustrating a case where an estimated movement path of an object is calculated as a turning trajectory centered on the turning center coordinates of the host vehicle. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0011] 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.

[0012] (Embodiment) A driving assistance device 1 according to an embodiment will be described.

[0013] 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 cabin 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 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."

[0014] [Basic configuration] 1, the driving assistance device 1 includes various in-vehicle 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 in-vehicle devices, determines whether or not there is a 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 warning.

[0015] 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, and a wheel speed sensor 14. 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.

[0016] 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 located in front and behind the host vehicle V1, and each radar ECU processes 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 is configured, for example, with various electronic components, such as a CPU, ROM, RAM, and input / output interface, mounted on a circuit board. 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 with various electronic components such as a CPU mounted on a circuit board, just like a radar ECU.

[0017] 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 acquire various information such as road markings, road markings, road edges, and object types. 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 on the resulting images. The imaging device 11 is mounted at an arbitrary position that allows it to capture an image of the predetermined area ahead of the vehicle V1.

[0018] 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.

[0019] 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.

[0020] The wheel speed sensor 14 is a known in-vehicle sensor that detects the rotation of the wheels of the host vehicle V1. The wheel speed sensor 14 is provided, for example, near each of the four wheels of the host vehicle V1 and outputs a detection signal corresponding to the magnitude of the rotation angle of each of the four wheels. The detection signal from the wheel speed sensor 14 is used, for example, to calculate the vehicle speed of the host vehicle V1.

[0021] The collision determination ECU 20 includes, for example, a host vehicle path calculation unit 21, an object path calculation unit 22, a host vehicle turning determination unit 23, a following determination unit 24, a collision determination unit 25, and an operation determination unit 26. 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, and when a TTC (time travel time difference) described below is equal to or less than a predetermined threshold, the collision determination ECU 20 generates and outputs signals for activating the brake ECU 31 and the alarm ECU 32, thereby controlling the operation of the safety device 30.

[0022] The vehicle path calculation unit 21 calculates an estimated movement path of the vehicle V1, which is expressed in a three-dimensional coordinate system defined by three axes: a distance X in the vehicle width direction, a distance Y in the vehicle traveling direction, and an elapsed time T from the present, as shown in FIG. 2, for example.

[0023] 2 will be referred to simply as "host vehicle estimated path PA1," and the estimated path of movement of the object detected by object detection device 10 in the same coordinate system will be referred to simply as "object estimated path PA2." Furthermore, hereinafter, a two-dimensional coordinate system defined by two orthogonal axes, distances X and Y, will be referred to simply as "two-dimensional coordinate system" or "XY plane," and a three-dimensional coordinate system defined by three axes, distances X and Y, and elapsed time T, will be referred to simply as "three-dimensional coordinate system."

[0024] Specifically, the vehicle path calculation unit 21 calculates the estimated vehicle trajectory and the estimated curve radius of the vehicle V1 on the XY plane based on, for example, the speed of change in the steering amount of the vehicle V1 and the vehicle speed. The vehicle path calculation unit 21 also calculates, for example, the existence region of the vehicle V1 on the XY plane, i.e., the vehicle existence region, as a rectangular region. The vehicle existence region is calculated based on, for example, dimensional data of the vehicle V1 pre-recorded in a recording medium (not shown) included in the collision determination ECU 20. At this time, the vehicle path calculation unit 21, for example, sets the current time as T0 and sets the origin coordinates (0, 0) of the XY plane to be the reference position of the vehicle V1 at time T0. The reference position is set, for example, to the center of the vehicle V1 in the vehicle width direction. The vehicle path calculation unit 21 also calculates the vehicle existence region at each position of the estimated vehicle trajectory, for example, from time T0 to time TN, when estimation ends. The orientation of the vehicle existence area at each position at each time is determined, for example, by the orientation of a tangent to the vehicle's estimated trajectory. Then, the vehicle path calculation unit 21 calculates, as the vehicle's estimated path PA1, the transition of the existence areas obtained by complementing the existence areas of multiple vehicles V1 in a three-dimensional coordinate system. Note that the complementation of the existence areas of multiple vehicles V1 is performed, for example, by connecting the four corners of the adjacent existence areas with straight lines.

[0025] The object path calculation unit 22 calculates an estimated object path PA2 based on, for example, information on the object's position and its relative speed with respect to the host vehicle V1 obtained by the object detection device 10. Specifically, for example, the object path calculation unit 22 calculates the path of the object on the XY plane, i.e., the object trajectory, based on information on the change in the target's position over time. The object path calculation unit 22 also calculates, for example, the object existence region on the object trajectory over time. The object existence region is calculated as, for example, a rectangular region that includes the entire outline of the object obtained by the object detection device 10, and its size is set based on the size of the object calculated by the object detection device 10. For example, the object path calculation unit 22 calculates the passing position of the object on the object trajectory after a predetermined elapsed time TN has elapsed from the current reference position of the object based on the object trajectory and the object's relative speed with respect to the host vehicle V1. The object path calculation unit 22 then calculates the estimated object path PA2 by interpolating multiple object existence regions from the current time to the elapsed time TN in a three-dimensional coordinate system.

[0026] The object path calculation unit 22 basically calculates the object estimated path PA2 as a straight trajectory, but when the host vehicle V1 is turning, the object is a preceding vehicle, and the host vehicle V1 is following the preceding vehicle, the object estimated path PA2 is calculated as a curved turning trajectory, which will be described in detail later.

[0027] The host vehicle turning determination unit 23 determines whether the host vehicle V1 is turning or not, and outputs a signal according to the determination result. The host vehicle turning determination unit 23 performs the determination process based on, for example, some of the output signals from the above-mentioned in-vehicle devices, etc. Details of the turning determination by the host vehicle turning determination unit 23 will be described later.

[0028] The following determination unit 24 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 24 determines, for example, whether a preceding vehicle exists in the traffic lane on the road in which the host vehicle V1 is traveling, and if a preceding vehicle exists, whether the host vehicle V1 is traveling following the preceding vehicle. Details of the following determination by the following determination unit 24 will be described later.

[0029] The collision determination unit 25 performs a collision determination to determine, for example, whether or not there is a possibility of a collision between the host vehicle V1 and an object detected by the object detection device 10. The collision determination unit 25 performs the above collision determination based on, for example, whether or not there is an intersection between the host vehicle estimated path PA1 calculated by the host vehicle path calculation unit 21 and the object estimated path PA2 calculated by the object path calculation unit 22. For example, if there is an intersection between the host vehicle estimated path PA1 and the object estimated path PA2, the collision determination unit 25 determines that there is a possibility of the host vehicle V1 colliding with the object, and if not, determines that there is no possibility of a collision, and outputs a signal according to the determination result.

[0030] For example, when the collision determination unit 25 determines that there is a possibility of a collision, the operation determination unit 26 calculates the TTC, which is obtained by dividing the relative distance between the host vehicle V1 and the detected object by the relative speed, and determines whether the TTC is equal to or less than a predetermined threshold. TTC is an abbreviation for Time To Collision, and is also referred to as "time to collision" or "time to collision." For example, when the operation determination unit 26 determines that the TTC is equal to or less than a predetermined threshold, the collision determination ECU 20 generates a signal to activate the safety device 30 and transmits an output signal to the safety device 30.

[0031] 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 an alarm ECU 32. The safety device 30 controls the braking and alarm activation of the host vehicle V1.

[0032] The brake ECU 31 controls the braking force of a brake actuator (not shown) of the host vehicle V1 based on, for example, an output signal from the collision determination ECU 20. The brake ECU 31 adjusts the deceleration amount 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.

[0033] 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 assists in avoiding a collision between the host vehicle V1 and another object by activating various warnings using sound, video display, etc.

[0034] The above is the basic configuration of the driving assistance device 1. The driving assistance device 1 has at least a collision determination ECU 20, and is required to be able to perform collision determination based on predetermined signals from various on-board devices mounted on the host vehicle V1 and control the operation of the safety device 30 in accordance with the determination result, and the types and arrangements of the on-board devices may be changed as appropriate. For example, the collision determination ECU 20 may be configured such that various determinations, such as turning determination of the host vehicle V1, following determination of a preceding vehicle, collision determination, and TTC threshold determination, are performed by a single determination unit.

[0035] [Example of collision prevention control] Next, an example of the processing operation of the driving support device 1 will be described.

[0036] The driving assistance device 1 executes the control flow of FIG. 3 when a predetermined start condition is satisfied, for example, when the ignition of the host vehicle V1 is turned on.

[0037] In step S110, for example, the object detection device 10 detects objects such as other vehicles and obstacles present around the host vehicle V1, particularly in front of the host vehicle V1. Also, in step S110, 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 according 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, such as 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."

[0038] In step S120, the vehicle path calculation unit 21 calculates the vehicle's estimated path PA1 in the three-dimensional coordinate system as described above based on various information such as the rate of change in steering amount and vehicle speed obtained from various sensors of the vehicle V1.

[0039] In step S130, for example, the collision determination ECU 20 determines whether the host vehicle V1 is turning and following the preceding vehicle based on various information such as the steering angle, yaw rate, and vehicle speed of the host vehicle V1 acquired from various sensors, etc. Then, for example, if the determination in step S130 is affirmative, the collision determination ECU 20 proceeds to step S140, and if the determination in step S130 is negative, the collision determination ECU 20 proceeds to step S150. Details of the turning following determination in step S130 will be described later.

[0040] In step S140, for example, the object path calculation unit 22 assumes that the target follows a turning path similar to the path of the turning host vehicle V1, i.e., the host vehicle trajectory, and calculates the object estimated path PA2 in a three-dimensional coordinate system as a curved path using a method described below. In step S140, the object estimated path PA2 is corrected to a curved path based on the path of the host vehicle V1 and calculated, thereby reducing the deviation between the object estimated path PA2 and the actual path of the object compared to when no correction is made. This further improves the accuracy of estimating whether or not there is an intersection between the host vehicle estimated path PA1 and the object estimated path PA2 and the point of the intersection, thereby improving the accuracy of the collision determination in step S160.

[0041] In step S150, for example, the object path calculation unit 22 assumes that the target moves at a constant speed in a straight line based on the direction of the target's velocity vector, which will be described later, and calculates the object's estimated path PA2 in a three-dimensional coordinate system as a straight line trajectory.

[0042] In step S160, for example, the collision determination unit 25 determines whether or not there is an intersection between the host vehicle estimated path PA1 calculated in step S120 and the object estimated path PA2 calculated in step S140 or step S150. Then, for example, if the determination in step S160 is affirmative, the collision determination ECU 20 proceeds to step S170, and if the determination in step S120 is negative, the collision determination ECU 20 returns the process to step S110.

[0043] In step S170, for example, the operation determination unit 26 calculates the value of the axis of elapsed time T [s] of the intersection coordinate Pi, which is the coordinate at which the host vehicle estimated path PA1 and the object estimated path PA2 first intersect in the three-dimensional coordinate system, as shown in Fig. 2. Then, for example, the operation determination unit 26 sets the value of the T axis of the calculated intersection coordinate Pi to the time from the current time to the collision timing, i.e., TTC.

[0044] In step S180, for example, the operation determination unit 26 determines whether the TTC calculated in step S170 is equal to or less than a predetermined threshold value. Then, for example, if the determination in step S180 is affirmative, the collision determination ECU 20 proceeds to step S190, and if the determination in step S180 is negative, the collision determination ECU 20 returns to step S110.

[0045] In step S190, for example, the collision determination ECU 20 generates an activation signal for the safety device 30 and outputs the generated signal to the brake ECU 31 and the alarm ECU 32. As a result, the safety device 30 automatically applies the brakes and issues an alarm without the driver's operation, alerting the driver and preventing a collision between the host vehicle V1 and the detected object. Then, for example, the collision determination ECU 20 repeats the above-described series of processes until a predetermined termination condition is met, such as the ignition being turned off.

[0046] The above is an example of collision prevention control by the driving assistance device 1. When the host vehicle V1 is turning and following a preceding vehicle, the driving assistance device 1 calculates the object estimated path PA2 as a curve in step S140, thereby reducing the deviation between the object estimated path PA2 and the actual path of the preceding vehicle and improving the accuracy of collision determination.

[0047] [Turning following judgment] Next, the turn following determination in step S130 will be described.

[0048] For example, when a predetermined start condition is satisfied, the collision determination ECU 20 starts the control flow shown in FIG. 4 and executes the process of cornering following determination.

[0049] In step S131, for example, the host vehicle turning determination unit 23 performs a turning determination as to whether or not the host vehicle V1 is turning. Then, for example, if the collision determination ECU 20 makes a positive determination in step S131, the process proceeds to step S132, and if the collision determination ECU 20 makes a negative determination in step S131, the process returns to step S131. For example, the host vehicle turning determination unit 23 determines that the host vehicle V1 is turning if the set conditions shown in FIG. 5 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. Note that "AND" in FIG. 5 means that the determination is met if all of the listed conditions are met, and "OR" means that the determination is met if at least one of the listed conditions is met. The same applies to FIG. 9, which will be described later.

[0050] Specifically, the host vehicle turning determination unit 23 determines whether or not the set conditions are met 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 three items: (1) the absolute value of the steering angular velocity is equal to or less than a start threshold, (2) the absolute value of the turning center curve R is equal to or less than a start threshold, and (3) the absolute value of the change in yaw rate is equal to or less than a start threshold. The turning center curve R is the radius of curvature (unit: meters) of the arc portion of a virtual circle that represents the path that the host vehicle V1 traces when turning. The start threshold is, for example, preset to a value according to the vehicle speed of the host vehicle V1, and is set to a smaller value as the vehicle speed decreases. The case where the set conditions are met is when the host vehicle V1 turns at a constant steering angle and travels in a substantially constant curve, but does not correspond to situations such as straight driving, meandering driving, or driving on a road with a variable curve R.

[0051] On the other hand, the reset conditions are set by, for example, two items: (i) the absolute value of the steering angular velocity exceeds an end threshold, and (ii) the absolute value of the turning center curve R exceeds an end threshold. The end threshold may be set to, for example, the same value as the start threshold, or may be set to a different value. The turning determination conditions described above are, for example, set in advance and recorded in a recording medium (not shown) of the collision determination ECU 20. Note that when the set conditions are met, the host vehicle turning determination unit 23 maintains the turning determination in an ON state until the reset conditions are met thereafter.

[0052] The subsequent processing of steps S132 to S134 corresponds to, for example, a plurality of determination items in the following determination executed by the following determination unit 24. In step S132, as shown in FIG. 6, for example, the following determination unit 24 determines whether the object detected by the object detection device 10 is in the vicinity of the host vehicle trajectory T of the host vehicle V1. V1 In FIG. 6, an example is shown in which the detected object is a preceding vehicle V2, and the vehicle trajectory T V1 The outline of the collision determination ECU 20 is indicated by a broken line. If the determination in step S132 is affirmative, the collision determination ECU 20 proceeds to step S133, and if the determination in step S132 is negative, the collision determination ECU 20 returns the process to step S131.

[0053] In step S132, the following determination unit 24 determines whether or not a part of the detected object is present within the area of ​​the traffic lane in which the host vehicle V1 is traveling, as shown in FIG. 7, for example. For example, let us assume that the white lines WL on the road, on the left and right sides of the lane in which the host vehicle V1 is traveling, are designated as left white lines LL and right white lines RL, respectively, and that the left white lines LL and right white lines RL are recognized by a known image recognition technology using the imaging device 11. In this case, the following determination unit 24 determines whether or not a part of the object is present within the area sandwiched between the left white line LL and the right white line RL, i.e., within the same white line. Specifically, when the preceding vehicle V2 is detected / recognized by the object detection device 10 or the imaging device 11, as shown in FIG. 7, for example, the following determination unit 24 determines whether or not a part of the object is present within the area sandwiched between the left white line LL and the right white line RL, i.e., within the same white line. CThe following determination unit 24 determines whether at least one of the four points P C If at least one of these is within the same white line, the preceding vehicle V2 is determined to be in the same lane as the host vehicle V1, and if not, the preceding vehicle V2 is determined to be not in the same lane as the host vehicle V1, and a signal according to the determination result is output. Although the above description has been given using a case where the target is the preceding vehicle V2 as a representative example, this is not limiting, and the same applies basically even if the detected object is not a vehicle. Hereinafter, for convenience of explanation, the above determination based on the recognized white lines LL, RL and the coordinates of the target will be referred to as "within the same white line determination."

[0054] In step S132, the following determination unit 24 calculates the lateral position of the target relative to the vehicle trajectory, instead of the within-the-same-white-line determination, and determines whether the target is within the vehicle trajectory T based on the calculated lateral position. V1 For convenience of explanation, this type of determination will be referred to as "lateral position determination."

[0055] The lateral position determination is performed, for example, by calculating the lateral position x of the target relative to the vehicle center locus drawn by the center position of the vehicle V1 indicated by the dashed line in FIG. R Calculate the horizontal position x R It is determined whether the lateral position x is within the vehicle width of the host vehicle V1. R The turning center of the vehicle V1 on the XY plane is defined as point P1, the estimated position of the target on the same plane is defined as point P2, and the position of the target after R correction is defined as point P RC The vehicle center trajectory and point P on the virtual line connecting points P1 and P2 are RC and distance. Horizontal position x R can be calculated geometrically, for example, by the following equation (1).

[0056]

number

[0057] In equation (1), x is the distance (unit: meters) between the host vehicle V1 and the target in the vehicle width direction of the host vehicle V1. y in equation (1) is the distance (unit: meters) from the mounting position of the object detection device 10 on the host vehicle V1 (hereinafter referred to as the "sensor position") to the target in the traveling direction of the host vehicle V1. z in equation (1) is the distance (unit: meters) from the sensor position in the traveling direction of the host vehicle V1 to the rear wheel axle of the host vehicle V1. |R| in equation (1) is the estimated radius of curvature R of the host vehicle V1, i.e., the absolute value of the distance (unit: meters) from the host vehicle V1 to point P1. sign(R) in equation (1) is a sign function that is +1 when R is positive and -1 when R is negative. For example, the positive and negative values ​​of R can be defined as positive when the turning trajectory of the host vehicle V1 traces a clockwise curve R and negative when the turning trajectory traces a counterclockwise curve R, but the opposite is also possible. The second term on the right side of equation (1) is the distance of the line connecting points P1 and P2, R E When R E is equivalent to

[0058] The following determination unit 24 determines, for example, the calculated lateral position x R The following determination unit 24 determines whether the lateral position x is within the vehicle width of the host vehicle V1. R If the target is within the vehicle width of the host vehicle V1, it is determined that the target is on the host vehicle trajectory, and if not, it is determined that the target is not on the host vehicle trajectory, and outputs a signal according to the determination result. V1 It may be determined that a target exists above.

[0059] In the next step S133, the following determination unit 24 determines, for example, the velocity vector V of the host vehicle V1. A1 and the object's velocity vector V B Then, for example, if the determination in step S133 is affirmative, the collision determination ECU 20 proceeds to step S134, and if the determination in step S133 is negative, the collision determination ECU 20 returns the process to step S131.

[0060] Specifically, in step S133, the following determination unit 24 determines whether or not the first condition or the second condition shown in Fig. 9 is satisfied. The first condition is, for example, whether "the ground speed of the target is equal to or greater than a threshold" and "the future velocity vector V of the host vehicle V1 is greater than or equal to a threshold" A1 and the target velocity vector V B The first condition is set as "the absolute value of the angular difference between the target and the target is less than a threshold value." The second condition is set as, for example, "the ground speed of the target is less than a threshold value." For ease of explanation, the determination of whether or not either the first condition or the second condition is satisfied will be referred to as "orientation determination."

[0061] Here, the velocity vector V under the first condition A1 , V B For example, as shown in FIG. 10, there is a subject vehicle V1 and a preceding vehicle V2 as a target, and the current velocity vector of the subject vehicle V1 on the XY plane is V A0 and the future one approaching the target is V A1 Let the current velocity vector of the preceding vehicle V2 be V B In other words, the above-mentioned angle difference in the first condition is the velocity vector V A0 Velocity vector V obtained by correcting the velocity vector V to align with the preceding vehicle V2 A1 and the current velocity vector V of the preceding vehicle V2. B 10 shows a typical example in which the preceding vehicle V2 is a four-wheeled vehicle, but the same applies to a two-wheeled vehicle such as a motorcycle.

[0062] Velocity vector V A1is calculated, for example, as follows. For example, as shown in FIG. 10, it is assumed that the host vehicle V1 and the preceding vehicle V2 are both turning on the XY plane around point P1, which is the turning center of the host vehicle V1. Also, the angle formed by a first imaginary straight line VL1 connecting the center of the host vehicle V1 to point P1 and a second imaginary straight line VL2 connecting point P2 located at the center of the preceding vehicle V2 to point P1 is θ1. In this case, the tangent direction of the arc obtained by rotating the first imaginary straight line VL1 by angle θ1 around point P1 corresponds to the direction of the velocity vector of the host vehicle V1. The corrected velocity vector V of the host vehicle V1 A1 is a velocity vector at a position 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 line. A1 is the current velocity vector V of the host vehicle V1. A0 This is obtained by applying the correction of the curve R at angle θ1 to the above.

[0063] 10, the vehicle V1 is turned by an angle θ1 so that the vehicle V1 is positioned on the extension of the second virtual straight line VL2, and the velocity vector V A1 is indicated by a dashed line, and the turning trajectory of the center position of the host vehicle V1 is indicated by a two-dot chain line.

[0064] Here, the coordinates of point P1 are (x c , y c ), and the coordinates of point P2 are (x obj , y obj ) and the angle θ1 is defined as positive when the estimated movement trajectory of the host vehicle V1, i.e., the direction from the host 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 θ1 is calculated, for example, by the following equation (2) when the curve R of the host vehicle V1 is negative, and by the following equation (3) when the curve R is positive and equal to or greater than 0.

[0065]

number

[0066] Furthermore, for example, when the ground speed of the target calculated based on signals from the object detection device 10 and the wheel speed sensor 14 is less than a threshold, the following determination unit 24 does not calculate the velocity vector and instead determines whether the second condition is met. In step S133, the determination in step S132 is affirmative, i.e., the target is determined to be on the host vehicle trajectory. Therefore, when the second condition is met, the following determination unit 24 regards the target as a stationary object and determines that the orientations of the host vehicle V1 and the target match. The case where the second condition in the orientation determination is met corresponds to, for example, a situation where the host vehicle V1 catches up with the preceding vehicle V2, as shown in FIG. 12.

[0067] In step S134, for example, the following determination unit 24 determines whether the detected object is a vehicle or a motorcycle based on signal processing in the object detection device 10 or the imaging device 11. Then, for example, if the determination in step S134 is affirmative, the collision determination ECU 20 proceeds to step S135, and if the determination in step S134 is negative, the collision determination ECU 20 returns to step S131.

[0068] In the final step S135, for example, the following determination unit 24 sets a flag indicating that the host vehicle V1 is turning to follow the preceding vehicle V2 and outputs a turning following ON signal. After that, for example, the collision determination ECU 20 returns the process to step S131. Note that the turning following flag set in step S135 is maintained until, for example, any of the determination conditions in steps S131 to S134 is no longer satisfied.

[0069] The above is the basic content of the turn following determination. Note that the determination processes in steps S131 to S134 shown in Fig. 4 are not limited to being performed in this order, and the order may be changed as appropriate within the possible range.

[0070] [Calculation of estimated object path during turning] Next, calculation of the estimated object path PA2 when the host vehicle V1 is turning and following the object will be described.

[0071] The estimated path of the turning host vehicle V1 and the estimated path of the detected object are calculated using a two-dimensional coordinate system with a distance X in the vehicle width direction of the host vehicle V1 and a distance Y in the vehicle traveling direction. The estimated path of the turning host vehicle V1, PA11, and the estimated path of the object, PA21, are represented, for example, as shown in FIG. 13. Conventionally, as shown in FIG. 13, the possibility of a collision has been determined when two estimated paths of the turning host vehicle V1, PA11 and PA21, intersect in the two-dimensional coordinate system. However, the accuracy of the determination was insufficient because time was not taken into consideration. Therefore, the accuracy of the collision determination between the host vehicle V1 and the object is improved by representing the estimated paths of the host vehicle V1 and the object in a three-dimensional coordinate system with two axes of distance X and Y plus an axis of elapsed time T from the present. For example, as shown in Figure 14, even if the vehicle's estimated path PA1 and the object's estimated path PA2 appear to intersect in the two-dimensional coordinate system shown in Figure 13, by representing them in a three-dimensional coordinate system, whether or not they intersect becomes clearer.

[0072] Through careful investigation by the inventors, it has been newly discovered that when a detected object is turning, the deviation between the estimated object path PA2 and the actual path of the object becomes large, which may result in insufficient accuracy in collision detection.

[0073] Specifically, when an estimated object path PA2 is predicted based on the current position and velocity of the object acquired by the object detection device 10, the wheel speed sensor 14, etc., the estimated object path PA2 becomes a straight trajectory, for example, as shown in FIG. 14. When a detected object is moving at a constant speed in a straight line, the estimated object path PA2 substantially coincides with the actual path of the object (hereinafter referred to as the "actual path" for convenience). However, when a detected object is turning, the estimated object path PA2 deviates more from the actual path than when the object is moving at a constant speed in a straight line. Furthermore, when an object is turning, it is difficult to calculate the turning trajectory based on the current position and velocity of the object.

[0074] Therefore, when the object is the preceding vehicle V2 and the host vehicle V1 is turning and following the preceding vehicle V2, the object path calculation unit 22 assumes that the preceding vehicle V2 traces a curved trajectory traveling on the turning trajectory of the host vehicle V1, and calculates an estimated object path PA2. This corresponds to the calculation of the estimated object path PA2 in step S150 described above.

[0075] Specifically, the object path calculation unit 22 calculates the estimated object path PA2 assuming that the preceding vehicle V2 traces a turning trajectory with the turning center coordinate of point P1 of the host vehicle V1 as the turning center, as shown in Fig. 15. In Fig. 15, the outline of the preceding vehicle V2 at time t-1 is indicated by a solid line, and the predicted time after time t-1 is time t, and the outline of the preceding vehicle V2 at time t is indicated by a dashed line. Times t-1 and t are times after zero, for example, with the time when object detection device 10 detects the preceding vehicle V2 being set as reference zero.

[0076] Here, for the preceding vehicle V2 in the two-dimensional coordinate system of the XY plane shown in FIG. 15, the center position at time t-1 is defined as point P2 t-1 , and its coordinates are (x t-1 , y t-1 ), the center position at time t is point P2 t , and its coordinates are (x t , y t ) In addition, for the preceding vehicle V2 in the same coordinate system, the velocity and acceleration at time t-1 are v t-1 , at-1 Let the velocity and acceleration at time t be v t , a t In Figure 15, the velocity v t-1 , v t , acceleration a t-1 , a t-1 The vectors corresponding to points P1 and P2 are shown with arrows. t-1 An imaginary line connecting points P1 and P2 t The angle between the virtual line connecting the preceding vehicle V2 and the preceding vehicle V2 is θ, the radius of curvature of the curve drawn by the preceding vehicle V2 is R, and the lateral position of the preceding vehicle V2 at time t-1 is x r Also, the difference between time t-1 and time t is Δt, and point P2 t-1 and point P2 t The distance between the preceding vehicle V2 and the target vehicle, i.e., the distance traveled by the preceding vehicle V2 in the predicted time interval, is defined as d. In this case, d = |v t-1 |Δt, R=x c -x r The turning angle θ of the preceding vehicle V2 at the predicted time interval is calculated by the following equation (4).

[0077] θ=d / R=|v t-1 |Δt / (x c -x r )···(4) And, if clockwise rotation of θ is positive and counterclockwise rotation is negative, then point P2 t The coordinates are calculated using the following equation (5).

[0078]

number

[0079]

number

[0080]

number

[0081] v in equation (7) xt , v yt are the velocities v t are the X- and Y-components of the vector. xt , a yt are the acceleration a t These are the X- and Y-components of the vector. When the host vehicle V1 is turning and following the preceding vehicle V2, the object path calculation unit 22 assumes that the preceding vehicle V2 traces a circular turning trajectory centered on point P1, and calculates the estimated object path PA2 using the above equations (4) to (9). As a result, the estimated object path PA2 is calculated as a curved trajectory, for example, as shown in FIG. 2, and the deviation from the actual path is reduced compared to when it is calculated as a straight line. Furthermore, improving the estimation accuracy of the estimated object path PA2 improves the calculation accuracy of the intersection between the host vehicle's estimated path PA1 and the estimated object path PA2 and the time to the intersection, i.e., TTC, resulting in improved collision detection accuracy.

[0082] According to this embodiment, the driving assistance device 1 calculates an estimated vehicle path PA1 and an estimated object path PA2 in a three-dimensional coordinate system formed by a distance Y in the traveling direction of the host vehicle V1, a distance X in the vehicle width direction, and an elapsed time T from the present. Then, when the object is a preceding vehicle V2 and the host vehicle V1 is following the object while turning, the object path calculation unit 22 calculates the estimated object path PA2 as a turning trajectory centered on the turning center coordinates of the host vehicle V1. Therefore, when the detected object is turning, the estimated object path PA2 is estimated to be curved, which reduces the deviation between the estimated object path PA2 and the actual path of the object and improves the accuracy of collision determination.

[0083] (Other embodiments) Although the present disclosure has been described with reference to the embodiments, it is understood that the present disclosure is not limited to the embodiments 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.

[0084] 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.

[0085] 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.

[0086] (Aspects of the present disclosure) The present disclosure described above can be understood from the following viewpoints, for example. [First viewpoint] A collision determination device that determines whether or not a collision occurs between a vehicle (V1) and an object detected by an object detection device (10), a vehicle path calculation unit (21) that calculates an estimated path of movement of the vehicle in a three-dimensional coordinate system defined by a distance in a traveling direction of the vehicle, a distance in a vehicle width direction of the vehicle, and an elapsed time from the present; an object path calculation unit (22) that calculates an estimated movement path of the object in the three-dimensional coordinate system based on the position of the object; a collision determination unit (25) that determines whether or not there is a collision between the host vehicle and the object based on whether or not there is an intersection between the host vehicle's estimated movement path and the object's estimated movement path, The object path calculation unit calculates an estimated movement path of the object as a turning trajectory centered on the turning center coordinates of the host vehicle when the object is a preceding vehicle (V2) and the host vehicle is turning to follow the object. [Second viewpoint] The collision determination device according to the first aspect further comprises a host vehicle turning determination unit (23) that determines whether the host vehicle is turning or not based on whether at least one of the radius of curvature of the turning trajectory of the host vehicle and the steering angular velocity of the host vehicle is equal to or less than a threshold value. [Third Perspective] a following determination unit (24) that determines whether the host vehicle is following the object based on a plurality of determination items; A collision judgment device described in the first or second aspect, wherein one of the plurality of judgment items is whether or not the object is present within the area sandwiched between two white lines (WL, WR) on the left and right of the lane in which the vehicle is traveling. [Fourth viewpoint] a following determination unit (24) that determines whether the host vehicle is following the object based on a plurality of determination items; A collision determination device according to any one of the first to third aspects, wherein one of the plurality of determination items is whether or not the lateral position of the object relative to the estimated movement path of the host vehicle is within the vehicle width of the host vehicle. [Fifth viewpoint] a following determination unit (24) that determines whether the host vehicle is following the object based on a plurality of determination items; A collision determination device according to any one of the first to fourth aspects, wherein one of the plurality of determination items is whether or not an angular difference between the velocity vector of the host vehicle at the point of the object and the velocity vector of the object at a ground speed equal to or greater than a predetermined value is equal to or less than a threshold value. [Sixth viewpoint] a following determination unit (24) that determines whether the host vehicle is following the object based on a plurality of determination items; The collision determination device according to any one of the first to fourth embodiments, wherein the following determination unit, when the ground speed of the object is less than a predetermined value, regards the object as a stationary object and determines that the object is a target to be followed by the host vehicle. [Seventh viewpoint] a following determination unit (24) that determines whether the host vehicle is following the object based on a plurality of determination items; The collision determination device according to any one of the first to sixth aspects, wherein one of the plurality of determination items is whether or not the object is a vehicle or a motorcycle. [Explanation of symbols]

[0087] 10... object detection device, 21... host vehicle path calculation unit, 22... object path calculation unit, 23... host vehicle turning determination unit, 24... following determination unit, 25... collision determination unit, LL, RL... white line, V1... host vehicle, V2... preceding vehicle

Claims

1. A collision determination device that determines whether or not a collision occurs between a vehicle (V1) and an object detected by an object detection device (10), a vehicle path calculation unit (21) that calculates an estimated movement path of the vehicle in a three-dimensional coordinate system defined by a distance in a traveling direction of the vehicle, a distance in a vehicle width direction of the vehicle, and an elapsed time from the present; an object path calculation unit (22) that calculates an estimated movement path of the object in the three-dimensional coordinate system based on the position of the object; a collision determination unit (25) that determines whether or not there is a collision between the host vehicle and the object based on whether or not there is an intersection between the host vehicle's estimated movement path and the object's estimated movement path, The object path calculation unit calculates an estimated movement path of the object as a turning trajectory centered on the turning center coordinates of the host vehicle when the object is a preceding vehicle (V2) and the host vehicle is turning while following the object.

2. 2. The collision determination device according to claim 1, further comprising a host vehicle turning determination unit (23) that determines whether the host vehicle is turning based on whether at least one of a radius of curvature in a turning trajectory of the host vehicle and a steering angular velocity of the host vehicle is equal to or less than a threshold value.

3. The vehicle further includes a following determination unit (24) that determines whether or not the host vehicle is following the object based on a plurality of determination items, 2. The collision determination device according to claim 1, wherein one of the plurality of determination items is whether or not the object is present in an area sandwiched between two white lines (WL, WR) on the left and right of the lane in which the host vehicle is traveling.

4. The vehicle further includes a following determination unit (24) that determines whether the host vehicle is following the object based on a plurality of determination items, 2. The collision determination device according to claim 1, wherein one of the plurality of determination items is whether or not a lateral position of the object with respect to the estimated movement path of the host vehicle is within a vehicle width of the host vehicle.

5. The vehicle further includes a following determination unit (24) that determines whether the host vehicle is following the object based on a plurality of determination items, 2. The collision determination device according to claim 1, wherein one of the plurality of determination items is whether or not an angular difference between a velocity vector of the host vehicle at the point of the object and a velocity vector of the object having a ground speed equal to or greater than a predetermined value is equal to or less than a threshold value.

6. The vehicle further includes a following determination unit (24) that determines whether or not the host vehicle is following the object based on a plurality of determination items, 2. The collision determination device according to claim 1, wherein the following determination unit, when the ground speed of the object is less than a predetermined value, regards the object as a stationary object and determines that the object is a target to be followed by the host vehicle.

7. The vehicle further includes a following determination unit (24) that determines whether or not the host vehicle is following the object based on a plurality of determination items, The collision determination device according to claim 1 , wherein one of the plurality of determination items is whether or not the object is a vehicle or a motorcycle.

Images