Driving assistance device

Abstract

A driver assistance device comprises a plurality of sensor devices attached to a reference vehicle (100), an attention attractant device configured to attract the attention of a driver of the reference vehicle (100), and at least one electronic control unit (10).The at least one electronic control unit (10) obtains reference vehicle information, obtains object information, estimates an expected path that the reference vehicle (100) will travel, determines whether a target object is present or not, determines whether there is a front space in front of the reference vehicle (100) or not, based on the object information, generates a request signal to attract the attention of the driver of the reference vehicle (100), prohibits the generation of the request signal if the electronic control unit (10) determines that the target object is present and there is no front space, and controls the attention arousal device to attract the driver's attention.

Description

BACKGROUND OF THE INVENTION 1. Field of the invention

[0001] The present invention relates to a driving assistance device which has a function to alert a driver of a vehicle to an object which is likely to cross a path which a vehicle is expected to travel (hereinafter simply referred to as an “expected path”). 2. Description of the state of the art

[0002] A driving assistance device attached to a vehicle that alerts the driver of the vehicle when it is likely that an object will cross an expected path of the vehicle is known in the prior art (hereinafter the vehicle in which the driving assistance device is attached is referred to as a "reference vehicle").

[0003] When the direction of travel of the reference vehicle intersects with the direction of travel of the object at an intersection point, a device, such as that disclosed in the Japanese unexamined patent application publication JP 2013-156688A (hereinafter referred to as a "prior art device"), predicts a first time period in which the reference vehicle reaches the intersection point and a second time period in which the object reaches the intersection point. Specifically, the prior art device predicts the first time period based on the position, direction of travel, and speed of the reference vehicle at the instantaneous time, and predicts the second time period based on the position, direction of travel, and speed of the object at the instantaneous time.

[0004] The prior art device has a pre-set overview. This overview has a vertical axis representing the first time period and a horizontal axis representing the second time period. Within the overview, one region where the absolute value of the time difference between the first and second time periods is less than or equal to a predetermined value is defined as a region where the object is likely to cross the expected path of the reference vehicle (i.e., a region where attention is attracted or generated). The other region of the overview is defined as a region where the object does not cross the expected path of the reference vehicle (i.e., a region where no attention is attracted or generated).The prior art device maps coordinates with components of the predicted first time period and second time period onto the overview, determines whether it is likely that the object will cross the expected path of the reference vehicle or not, by specifying the area in which the coordinates are positioned, and attracts attention if it is likely that the object will cross the expected path of the reference vehicle.

[0005] The publication EP 3 081 447 A1 discloses a method for assisting a driver in operating a vehicle, comprising the following steps: generating sensor data by means of at least one sensor; physically sensing the environment of a host vehicle and / or by receiving data that transmits information about the environment of a host vehicle; detecting an object in a path of the host vehicle based on the sensor data; controlling a distance between the host vehicle and the detected object based on a preset gap; estimating environmental conditions of the host vehicle based on the sensor data; determining gap adjustment indicators associated with the estimated environmental conditions, each gap adjustment indicator indicating an increase or decrease of the preset gap; and adjusting the preset gap based on the gap adjustment indicators.

[0006] German patent application DE 10 2008 019 174 A1 discloses a method in which the current position, information about the current path, and the speed of a vehicle are determined. Based on the determined information, the vehicle's speed is controlled and / or regulated. A predetermined vehicle speed, a current driving position, and current drive and brake torque are set, regulated, and / or controlled depending on parameters of the preceding path and / or a parameter of a preceding vehicle. An independent claim also includes a device for carrying out a vehicle operating procedure, comprising a control unit.

[0007] Publication JP 2014 - 98 965 A discloses a drive support device that can provide suitable drive support by appropriately exercising the drive support.

[0008] Publication JP 2016 - 95 697 A discloses an attention arousal device for suppressing a feeling of discomfort imposed on a driver by attention arousal at an intersection. SUMMARY OF THE INVENTION

[0009] The configuration of the prior art device could alert the driver to the object even if it is actually very unlikely that the object will cross the expected path of the reference vehicle. That is, for example, even if the direction of travel of the reference vehicle intersects the direction of travel of the object at the point of intersection, and even if a determination to alert the driver to the object is made for the predicted first and second time periods, the object could not pass in front of the reference vehicle if another vehicle is traveling in front of it and if, due to the presence of the other vehicle, there is no space that would allow the object to pass in front of the reference vehicle. Consequently, it is very unlikely that the object will cross the expected path of the reference vehicle.The prior art device does not take into account whether or not there is space in front of the reference vehicle. Therefore, the prior art device always generates attention if it determines, based on the predicted first and second time periods, that attention is required. Consequently, the prior art device could draw attention to an object that does not require attention and could thus create a feeling of discomfort for the driver.

[0010] The present invention provides a driving assistance device that can make a driver of a reference vehicle more appropriately aware.

[0011] One aspect of the present invention relates to a driving assistance device comprising a plurality of sensor devices mounted in a reference vehicle, an attention-attracting device configured to attract the attention of a driver of the reference vehicle, and at least one electronic control unit. The at least one electronic control unit is configured to obtain, based on sensor outputs, reference vehicle information including parameters relating to the vehicle speed and yaw rate of the reference vehicle; and, based on sensor outputs, object information including the relative position of an object surrounding the reference vehicle, the object's direction of travel, and its speed.to estimate an expected path that the reference vehicle is expected to travel based on the reference vehicle information; to determine, based on the object information, whether a target object, which is an object likely to cross the expected path, is present within a threshold time period; to determine, based on at least the object information, whether or not there is a front clearance, which is a space that allows the target object to pass in front of the reference vehicle; to generate a request signal to attract the attention of the driver of the reference vehicle if the electronic control unit determines that the target object is present and that there is a front clearance; to prevent the generation of the request signal if the electronic control unit determines that the target object is present and that there is no front clearance; and to control the attention-attracting device.to attract the driver's attention in response to the generation of the request signal.

[0012] According to the aspect of the present invention, the electronic control unit determines whether the target object, which is the object likely to cross the expected path of the reference vehicle within the threshold time period, is present or not. If the electronic control unit determines that the target object is present, it attracts the attention of the driver of the reference vehicle. However, even if the electronic control unit determines that the target object is present (that is, even if the electronic control unit attracts attention), the target object could not pass in front of the reference vehicle if there is no space in front of the reference vehicle that would allow the object to pass in front of it. Consequently, it is actually very unlikely that the target object will cross the expected path of the reference vehicle within the threshold time period.In such a case, attracting attention is unnecessary and can cause the driver discomfort. Therefore, even if the electronic control unit determines that the target object is present, it is desirable not to attract attention if it is actually very unlikely that the target object will cross the expected path of the reference vehicle within the threshold time period due to the absence of the area in front.

[0013] Therefore, according to the aspect of the present invention, the electronic control unit is configured to determine, based on at least the object information, whether or not there is a front space, which is a space that allows the target object to pass in front of the reference vehicle, and the electronic control unit is configured to prohibit the generation of the request signal if the electronic control unit determines that the target object is present and that there is no front space.

[0014] According to the aspect of the present invention, the electronic control unit determines, based on at least the object information, whether or not there is a frontal area in front of the reference vehicle, which is the area that allows the target object to pass in front of the reference vehicle. If the electronic control unit determines that there is no frontal area, it prevents the target object from attracting attention, even if the electronic control unit determines that the target object is present. If there is no frontal area, the target object could not pass in front of the reference vehicle. Thus, it is highly unlikely that the target object will cross the expected path of the reference vehicle within the threshold time period.Accordingly, even if the electronic control unit determines that the target object is present, the aspect of the present invention can prevent the detection of an alert if it is actually very unlikely that the target object will cross the expected path of the reference vehicle within the threshold time period due to the absence of the front area. Thus, the aspect of the present invention can significantly reduce the possibility of detection of an alert that does not need to be performed and can more appropriately attract the attention of the driver of the reference vehicle.

[0015] In the driving assistance device according to the present invention, the electronic control unit is configured to extract an object located around the reference vehicle. The electronic control unit determines whether all predetermined conditions of forward and backward distance, horizontal distance, and horizontal velocity are met. The forward and backward distance condition is a condition that the forward and backward distance, which is the distance from the reference vehicle to the extracted object in a direction of travel of the reference vehicle, is less than or equal to a predetermined forward and backward distance threshold.The horizontal distance condition is a condition that a horizontal distance is less than or equal to a predetermined horizontal distance threshold. Horizontal distance is the distance from the reference vehicle to the extracted object in an orthogonal direction, which is a direction orthogonal with respect to the direction of travel of the reference vehicle. The horizontal velocity condition is a condition that a horizontal velocity, which is the velocity of the extracted object in the orthogonal direction, is less than or equal to a predetermined horizontal velocity threshold. The electronic control unit is configured to determine that there is no frontal space if the electronic control unit determines that the extracted object satisfies all of the conditions.

[0016] The aspect of the present invention can consider the direction of travel of the object fulfilling the horizontal speed condition as approximately parallel to the direction of travel of the reference vehicle by setting the horizontal speed threshold to a suitable value. Thus, in the configuration described above, the electronic control unit determines whether the object, whose direction of travel is approximately parallel to the direction of travel of the reference vehicle, is located within a "range which has a length equal to the forward and backward distance threshold from the reference vehicle in the direction of travel of the reference vehicle and a length equal to the horizontal distance threshold from the reference vehicle on both sides of the reference vehicle in the orthogonal direction of the reference vehicle (hereinafter referred to as a "front range")".If the electronic control unit determines that an object is present, it determines that there is no frontal clearance. Accordingly, by setting each of the forward and reverse distance thresholds and the horizontal distance threshold to an appropriate value, if the object, whose direction of travel is approximately parallel to the reference vehicle, is within the frontal clearance, the object obstructs the target object's movement. Therefore, it is highly unlikely that the target object will cross the expected path of the reference vehicle within the threshold time period. The configuration described above can determine that there is no frontal clearance when it is highly unlikely that the target object will cross the expected path of the reference vehicle within the threshold time period. Thus, the configuration can appropriately determine whether or not there is a frontal clearance.

[0017] In the driving assistance device according to the present invention, the electronic control unit can be configured to determine whether the reference vehicle is traveling straight ahead or not. If the electronic control unit determines that the reference vehicle is traveling straight ahead, it can estimate the expected path to be a path extending linearly from the reference vehicle in the direction of travel and having a predetermined length. The electronic control unit can be configured to set the forward and reverse distance thresholds such that these are less than or equal to the predetermined length of the expected path of the reference vehicle.

[0018] According to the aspect of the present invention, the forward and backward distance thresholds are less than or equal to the length of the expected path of the reference vehicle. Thus, the front area is present on the expected path that the target object is expected to traverse. Accordingly, if the object, whose direction of travel is approximately parallel to that of the reference vehicle, is present within the front area, the object impedes the movement of the target object. Consequently, it is highly unlikely that the target object will cross the expected path of the reference vehicle within the threshold time period. The configuration described above can determine that there is no front area if it is highly unlikely that the target object will cross the expected path of the reference vehicle within the threshold time period. Thus, the configuration can more appropriately determine whether or not the front area exists. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Features, advantages and technical and industrial significance of exemplary embodiments of the invention are described below with reference to the attached drawings, in which the same reference numerals denote the same elements and in which: Fig. 1 a diagram illustrating a driving assistance device according to an embodiment of the present invention (hereinafter referred to as the “device embodied herein”) and a vehicle to which the driving assistance device is applied; Fig. 2 a diagram representing coordinate axes set around the reference vehicle in an nth cycle by the device embodied herein; Fig. 3 a diagram that represents a positional relationship between the reference vehicle and an object in an (n-1)th cycle and the nth cycle and is used to describe the acquisition of object information of the object in the nth cycle; Fig. 4A a diagram that represents a positional relationship on the road between the reference vehicle and the object that is present around the reference vehicle in the nth cycle and is used to describe the presence or absence of a target object in the nth cycle when the reference vehicle makes a right turn; Fig. 4B a diagram that represents a positional relationship on the road between the reference vehicle and the object that is present around the reference vehicle in the nth cycle and is used to describe the presence or absence of a target object in the nth cycle when the reference vehicle is traveling straight ahead; Fig. 5 a diagram showing the reference vehicle and the object with the same positional relationship as in Fig. 4B represents and is used to describe the presence or absence of a front space in the nth cycle; Fig. 6 a flowchart (1) representing a routine executed by a CPU of a driver assistance ECU of the device embodied herein (hereinafter referred to as a ‘CPU of the device embodied herein’); Fig. 7A a flowchart (2) representing a routine that is executed by the CPU of the device embodied herein; Fig. 7B a flowchart (3) representing a routine that is executed by the CPU of the device embodied herein; and Fig. 8 a flowchart (4) representing a routine that is executed by the CPU of the device embodied herein. DETAILED DESCRIPTION OF THE EXAMPLES OF EXECUTION Example of Execution

[0020] A driving assistance device according to an exemplary embodiment (hereinafter referred to as the "device embodied herein") is described below with reference to the drawings. The device embodied herein is applied to a reference vehicle 100, which is in Fig. The device shown in Figure 1 is applied. The reference vehicle 100 is an automobile that includes a machine (not shown) as a power source. The device embodied herein comprises a driver assistance ECU (an example of an electronic control unit) 10 and a display ECU 20.

[0021] ECU stands for electronic control unit. Each of the Driving Assistance ECU 10 and the Display ECU 20 is an electronic control unit that incorporates a key component of a microcomputer, including a CPU, ROM, RAM, interface, and similar components. The CPU performs various functions, described below, by executing instructions (routines) stored in a memory (ROM). The Driving Assistance ECU 10 and the Display ECU 20 can be combined into a single ECU.

[0022] The driver assistance ECU 10 and the display ECU 20 are connected to each other via a communication and sensor system control area network (CAN, “controller area network”) 90 in a way that enables the exchange of data (communicative).

[0023] The reference vehicle 100 comprises a vehicle speed sensor 11, a wheel speed sensor 12, a yaw rate sensor 13, a left indicator sensor 14L, a right indicator sensor 14R, a radar sensor 15, and a display device 21. Sensors 11 to 15 are connected to the driving assistance ECU 10, and the display device 21 is connected to the display ECU 20. While the reference vehicle 100 comprises a plurality of sensors that detect a driving condition of the reference vehicle 100 in addition to sensors 11 to 15, the present embodiment will describe sensors with reference to the configuration of the driving assistance device disclosed in this specification.

[0024] The vehicle speed sensor 11 detects the speed (vehicle speed) SPDv [km / h] of the reference vehicle 100 and outputs a signal indicating the vehicle speed SPDv to the driving assistance ECU 10. The driving assistance ECU 10 obtains the vehicle speed SPDv based on the signal output by the vehicle speed sensor 11 each time a predetermined calculation period Tcal [s] elapses.

[0025] The wheel speed sensor 12 is mounted on each of the right and left front wheels (not shown) and each of the right and left rear wheels (not shown) of the reference vehicle 100. Each wheel speed sensor 12 detects a rotational speed WS [rps] from each wheel and outputs a signal indicating the rotational speed WS to the drive assistance ECU 10. The drive assistance ECU 10 obtains the rotational speed WS from each wheel based on the signal detected by each wheel speed sensor 12 at each predetermined calculation period Tcal. The drive assistance ECU 10 can then obtain the vehicle speed SPDv [m / s] based on the rotational speed WS.

[0026] The yaw rate sensor 13 detects the angular velocity (yaw rate) Y [° / s] of the reference vehicle 100 and outputs a signal indicating the yaw rate Y to the driving assistance ECU 10. The driving assistance ECU 10 obtains the yaw rate Y based on the signal received from the yaw rate sensor 13 each time the calculation period Tcal elapses.

[0027] When a left indicator changes from a switched-off state to a flashing state, the sensor of a left indicator 14L outputs a signal indicating the flashing state of the left indicator to the driving assistance ECU 10. The driving assistance ECU 10 obtains the state of the left indicator based on the signal received from the sensor of a left indicator 14L each time the calculation period Tcal expires.

[0028] When a right indicator changes from a deactivated state to a flashing state, the sensor of a right indicator 14R outputs a signal indicating the flashing state of the right indicator to the driving assistance ECU 10. The driving assistance ECU 10 obtains the state of the right indicator based on the signal received from the sensor of a right indicator 14R each time the calculation period Tcal elapses.

[0029] The radar sensor 15 is located at each of the left end, center, and right end of a front end section of the reference vehicle 100. Each radar sensor 15 transmits an electromagnetic wave in a front left diagonal direction, a front front direction, and a front right diagonal direction of the reference vehicle 100. If a body, such as another vehicle or a pedestrian, is present within the range of the electromagnetic wave (hereinafter referred to as the "transmitted wave"), the transmitted wave is reflected by the body. Each radar sensor 15 receives the reflected transmitted wave (hereinafter referred to as a "reflected wave"). Each radar sensor 15 outputs a signal indicating the transmitted wave and a signal indicating the reflected wave to the driving assistance ECU 10.In the following, a body that is within the range of the electromagnetic wave is referred to as an "object".

[0030] The driving assistance ECU 10 determines whether an object is present that is likely to cross an expected path of the reference vehicle 100 within a threshold time period (described below). If the driving assistance ECU 10 determines that an object is present, it generates a request signal to alert the driver of a reference vehicle 100 to the object and transmits the request signal to the display ECU 20.

[0031] The display device 21 is a display device located in a position that is visually perceptible from the driver's seat of the reference vehicle 100 (for example, on a dashboard). When the display ECU 20 receives the request signal from the driver assistance ECU 10, the display ECU 20 transmits an instruction signal to the display device 21. When the display device 21 receives the instruction signal from the display ECU 20, the display device 21 displays information to attract the driver's attention. The display device 21 may be a head-up display, a center display, or the like. Summary of the operation of the device embodied here

[0032] Next, a summary of the operation of the device embodied herein will be described. The device embodied herein performs two types of determinations: target object determination and frontal area determination, which are described below. Target object determination is a determination of whether an object likely to cross the expected path of the reference vehicle 100 within the threshold time period (hereinafter referred to as a "target object") is present. Frontal area determination is a determination of whether a frontal area, which is a space that allows the target object to pass in front of the reference vehicle 100, exists in front of the reference vehicle 100. Based on the result of these two determinations, the device embodied herein determines whether or not to attract attention. Target object determination and frontal area determination are described in detail below. A. Joint operation in target object identification and frontal area identification

[0033] First, a joint operation in target object determination and front area determination is described. When a machine switch (ignition key switch), not shown, of reference vehicle 100 is switched to an ON state, the device embodied here, before the machine switch is switched to an OFF state, obtains information about reference vehicle 100 (reference vehicle information) each time the computation time period Tcal elapses and sets coordinate axes based on the reference vehicle information with the instantaneous position of reference vehicle 100 as one origin. The device embodied here determines whether an object is present around reference vehicle 100 or not. If the device embodied here determines that an object is present, the device embodied here obtains object information about the object. The joint operation is described in more detail below.Hereinafter, a period in which the machine switch is toggled from the ON state to the OFF state is referred to as a "machine ON period." For any element e, the element e in the nth computation cycle is denoted by e(n), and a time when the machine switch is toggled to the ON state is defined as n = 0. The reference vehicle 100 can, for example, be a hybrid vehicle or an electric car. In such a case, for a start switch (for example, a ready switch) that puts the reference vehicle 100 into a state in which it is capable of driving, switching the start switch to the ON state has the same meaning as switching the machine switch to the ON state. Switching the start switch to the OFF state has the same meaning as switching the machine switch to the OFF state. Obtaining reference vehicle information and setting coordinate axes

[0034] The driving assistance ECU 10 of the device embodied herein obtains the vehicle speed SPDv(n), the wheel speed SW(n), the yaw rate Y(n), and the states of the right and left indicators as the reference vehicle information based on the signals received from sensor 11, sensor 12, sensor 13, sensor 14L, and sensor 14R, and stores the reference vehicle information in the RAM of the driving assistance ECU 10. The driving assistance ECU 10 sets coordinate axes based on the reference vehicle information with the instantaneous position of the reference vehicle 100 as one origin. Specifically, as in Fig. As shown in Figure 2, the driving assistance ECU 10 sets the center of the front end section of the reference vehicle 100 as an origin O(n) (0,0) in the nth cycle, sets an x-axis in a direction of travel TDv(n) of the reference vehicle 100 in the nth cycle, and sets a y-axis in a direction that passes through the origin O(n) and is orthogonal with respect to the direction of travel TDv(n) of the reference vehicle 100. The x-axis has the direction of travel TDv(n) as a positive direction, and the y-axis has the left direction of travel of the reference vehicle 100 as a positive direction. The driving assistance ECU 10 determines the direction of travel TDv(n) from the vehicle speed SPDv(n) (or the wheel speed SW(n)) and the yaw rate Y(n) in the nth cycle. The driver assistance ECU 10 stores information specifying the coordinate axes in the RAM of the driver assistance ECU 10.The units of an x-component and a y-component in the xy-coordinate plane are [m]. Procurement of object information

[0035] The driving assistance ECU 10 determines whether an object is present around the reference vehicle 100 or not, based on the signals received by each radar sensor 15. If the driving assistance ECU 10 determines that an object is present, it obtains the distance from the reference vehicle 100 to the object and the object's azimuth relative to the reference vehicle 100. The driving assistance ECU 10 calculates the coordinates (x(n),y(n)) of a relative position P(n) of the object in the nth cycle with respect to the position of the reference vehicle 100 in the nth cycle (i.e., the origin O(n)) of the object's distance and azimuth in the nth cycle. Additionally, as described in Fig. As shown in Figure 3, the driving assistance ECU 10 calculates a direction of travel TDo(n) and a speed SPDo(n) [km / h] of an object 200 in the nth cycle by a procedure below. Object 200 is an example of the object. Fig. In 3, reference vehicle 100 and object 200 are represented by a solid line in the nth cycle, and reference vehicle 100 and object 200 are represented by a dashed line in the (n-1)th cycle. Calculation of the object's direction of travel TDo

[0036] First, the driving assistance ECU 10 calculates a position vector p(n) of the relative position P(n) of object 200 in the n-th cycle and the position vector p(n-1) of the relative position P(n-1) of object 200 in the (n-1)-th cycle by a general formula (1) and a general formula (2). p(n)=(x(n),y(n)) p(n−1)=(x(n−1),y(n−1))

[0037] As can be seen from general formula (1) and general formula (2), the components of the position vector p(n) are equal to the coordinates of the relative position P(n) of object 200 in the nth cycle, and the components of the position vector p(n-1) are equal to the coordinates of the relative position P(n-1) of object 200 in the (n-1)th cycle. That is, the position vector p(n) is a vector with origin O(n) in the nth cycle as a starting point, and the position vector p(n-1) is a vector with origin O(n-1) in the (n-1)th cycle as a starting point. Thus, both vectors have different starting points. Accordingly, the driving assistance ECU 10 transforms the position vector p(n-1) into a position vector pc(n-1) with the origin O(n) in the nth cycle as a starting point by a general formula (3). pc(n−1)=p(n−1)−O(n−1)O(n)

[0038] The vector O(n-1)O(n) is a vector from the origin O(n-1) in the (n-1)th cycle to the origin O(n) in the nth cycle. The vector O(n-1)O(n) is a vector that has a magnitude of a value obtained by multiplying the vehicle speed SPDv(n-1) of the reference vehicle 100 in the (n-1)th cycle by the computation time period Tcal, and has a direction of travel TDv(n-1) in the (n-1)th cycle.

[0039] The driving assistance ECU 10 calculates an offset direction of object 200 from the (n-1)th cycle to the nth cycle by subtracting the general formula (3) from the general formula (1) by the general formula (4). p(n)−pc(n−1)=p(n)−p(n−1)+O(n−1)O(n)

[0040] The driving assistance ECU 10 calculates the offset direction of the object, represented by the general formula (4), as the driving direction TDo(n) of object 200 in the nth cycle. Calculation of the object's velocity SPDo

[0041] Next, the driving assistance ECU 10 calculates the velocity SPDo(n) of object 200 in the nth cycle using the general formula (5). The magnitude, order of magnitude, or absolute value of a vector X is denoted by abs{X}. SPDo(n)=abs{p(n)−p(n−1)+O(n−1)O(n)} / Tcal

[0042] This means that the driving assistance ECU 10 calculates the velocity SPDo(n) of object 200 in the nth cycle, a value obtained by dividing the magnitude of the offset (abs{p(n) - p(n-1) + O(n-1)O(n)}) of object 200 from the (n-1)th cycle to the nth cycle by the computation time period Tcal. The driving assistance ECU 10 stores the coordinates of the object's relative position P(n), the object's direction of travel TDo(n), and the object's velocity SPDo(n) in its RAM as object information. When each radar sensor outputs signals reflected by the same object to the driving assistance ECU 10, the driving assistance ECU 10 obtains the object information regarding that same object based on these signals. B. Operation regarding target object determination

[0043] Next, an operation regarding target determination is described. During the machine-on period, the driving assistance ECU 10 determines each time the computation time period Tcal elapses whether the reference vehicle 100 is making a left turn, a right turn, or traveling straight ahead, and estimates the expected path of the reference vehicle 100 according to the determination result. The expected path is estimated to have an arc-shaped path if the reference vehicle 100 is making a left or right turn (including the case where the reference vehicle 100 temporarily stops while making the left or right turn), and is estimated to have a line-segment shape if the reference vehicle 100 is traveling straight ahead (including the case where the reference vehicle 100 temporarily stops while traveling straight ahead).The driving assistance device ECU 10 estimates the expected path of the object and determines whether an object that periodically intersects the expected path of the reference vehicle 100 within the threshold time is present. If the driving assistance ECU 10 determines that the object is present, it determines that attention should be drawn to the object and sets the value of the attention arousal marker for the object to 1. If the driving assistance ECU 10 determines that the object is not present, it determines that attention should not be drawn to the object and sets the value of the attention arousal marker for the object to 0. A procedure for target object determination is described in more detail below. Left turn start condition and right turn start condition

[0044] When the driving assistance ECU 10 determines whether the operating vehicle 100 will make a left turn, a right turn, or continue straight ahead, the driving assistance ECU 10 first determines whether the reference vehicle 100 will begin to make a left turn or a right turn. The driving assistance ECU 10 determines that the reference vehicle 100 will begin to make a left turn if a left turn start condition, described below, is met. The driving assistance ECU 10 determines that the reference vehicle 100 will begin to make a right turn if a right turn start condition, described below, is met. Left turn start condition

[0045] The left turn start condition applies if any of the following conditions L1, L2, L3 are met.

[0046] (Condition L1) The left indicator changes from the off state to the flashing state when the vehicle speed SPDv(n) is greater than or equal to a first vehicle speed threshold SPDv1th (0 km / h in this example) and less than or equal to a second vehicle speed threshold SPDv2th (20 km / h in this example). The first vehicle speed threshold SPDv1th and the second vehicle speed threshold SPDv2th are preset as a lower and upper limit, respectively, of a general speed range when the reference vehicle 100 begins to make a left turn. The same applies to a right turn.

[0047] (Condition L2) When the left indicator is in the flashing state, the vehicle speed SPDv(n) is changed to a speed that is greater than or equal to the first vehicle speed threshold SPDv1th and less than or equal to the second vehicle speed threshold SPDv2th.

[0048] (Condition L3) The left indicator changes from the off state to the flashing state at the same time when the vehicle speed SPDv(n) changes to a speed greater than or equal to the first vehicle speed threshold SPDv1th and less than or equal to the second vehicle speed threshold SPDv2th. Right turn start condition

[0049] The right turn start condition applies if any of the following conditions R1, R2, R3 are true.

[0050] (Condition R1) The right indicator changes from the off state to the flashing state when the vehicle speed SPDv(n) is greater than or equal to the first vehicle speed threshold SPDv1th and less than or equal to the second vehicle speed threshold SPDv2th.

[0051] (Condition R2) When the right indicator is in the flashing state, the vehicle speed SPDv(n) is changed to a speed greater than or equal to the first vehicle speed threshold SPDv1th and less than or equal to the second vehicle speed threshold SPDv2th.

[0052] (Condition R3) The right indicator changes from the off state to the flashing state at the same time when the vehicle speed SPDv(n) changes to a speed greater than or equal to the first vehicle speed threshold SPDv1th and less than or equal to the second vehicle speed threshold SPDv2th. Left turn condition and right turn condition

[0053] Generally, while the reference vehicle 100 is making a left turn or a right turn (that is, while the reference vehicle 100 begins to make a left turn or a right turn, actually makes a left turn or a right turn, and then completes the left turn or the right turn), the vehicle speed SPDv(n) of the reference vehicle 100 satisfies SPDv1th ≤ SPDv(n) ≤ SPDv2th, and the left indicator or the right indicator remains in the flashing state. Accordingly, once the left turn start condition or the right turn start condition is met, conditions L1 to L3 or conditions R1 to R3 are not met until the reference vehicle 100 completes the left turn or the right turn. Thus, the left turn start condition or the right turn start condition is not met repeatedly.Accordingly, after the driving assistance ECU 10 determines that the left turn start condition or the right turn start condition is met, the driving assistance ECU 10 determines that the reference vehicle 100 is making a left turn or a right turn before the driving assistance ECU 10 determines that the left indicator or the right indicator is not in the flashing state (i.e., has not been changed to the off state), or before the driving assistance ECU 10 determines that a “total rotation angle θ(n) (described below) of the reference vehicle 100 from the start of a left turn or a right turn at the present time” exceeds a “general rotation angle (in the present example 90°) at the time of making the left turn or the right turn”. Initialization of the rotation angle θtotal and calculation of the rotation angle θ(n)

[0054] After the driving assistance ECU 10 determines that the left turn start condition or the right turn start condition is met, the driving assistance ECU 10 calculates the total rotation angle θ(n) of the reference vehicle 100 while determining that the reference vehicle 100 is making a left turn or a right turn. Specifically, if the driving assistance ECU 10 determines that the left turn start condition or the right turn start condition is met in an m-th cycle, the driving assistance ECU 10 calculates the total rotation angle θ(n) of the reference vehicle 100 from the m-th cycle to the n-th cycle using general formula (6) and general formula (7). If n=m,θtotal(m)=0° If n≥m+1,θtotal(n)=θtotal(n−1)+θ(n)

[0055] This means that the device embodied here sets (initializes) the rotation angle θtotal(m) to 0° in a cycle (n=m) when the driving assistance ECU 10 determines that the left turn start conditions or the right turn start conditions are met. Otherwise (n≥m+1), the driving assistance ECU 10 calculates the rotation angle θtotal(n) by adding an instantaneous rotation angle θ(n) to the immediately preceding rotation angle θtotal(n-1). The instantaneous rotation angle θ(n) is calculated by multiplying the yaw rate Y(n) in the nth cycle by the computation time period Tcal. The mean of the yaw rates Y obtained for a multitude of immediately preceding cycles including Y(n) (hereinafter referred to as a "uniform yaw rate Ys(n)") can be used as the yaw rate Y(n). The driving support ECU 10 stores the rotation angle θtotal(n) in the RAM of the driving support ECU 10. Straight-ahead driving condition

[0056] The driving assistance ECU 10 determines that the reference vehicle 100 is traveling straight ahead if the driving assistance ECU 10 determines that the left indicator and the right indicator are in the off state, while the left turn start condition and the right turn start condition are not met once, after the driving assistance ECU 10 determines that the previous left turn or the previous right turn has been completed. The driving assistance ECU 10 stores the determination result (that is, whether the reference vehicle 100 is making a left turn, a right turn, or traveling straight ahead) in the RAM of the driving assistance ECU 10.

[0057] Estimation of the left-hand expected path and the right-hand expected path of the reference vehicle 100

[0058] If the driving assistance ECU 10 determines that the reference vehicle 100 is making a left turn or a right turn, and if the driving assistance ECU 10 determines that the reference vehicle 100 is going straight ahead, the driving assistance ECU 10 estimates an expected path through which a left end OL(n) (see Fig. 4A and Fig. 4B) of the front end section of the reference vehicle 100 runs as expected (left-hand expected path), and an expected path through which a right end OR(n) (see Fig. 4A and Fig. 4B) of the front end section of the reference vehicle 100 proceeds as expected (right-hand expected path). If the driving assistance ECU 10 determines that the reference vehicle 100 is making a left turn or a right turn, the driving assistance ECU 10 estimates the left-hand expected path and the right-hand expected path as paths with an arc-shaped form. If the driving assistance ECU 10 determines that the reference vehicle 100 is traveling straight ahead, the driving assistance ECU 10 estimates the left-hand expected path and the right-hand expected path as paths with a linear form and a finite length (that is, a line segment form). Hereinafter, the left-hand expected path and the right-hand expected path with an arc-shaped form are accordingly referred to as the "first left-hand expected path" and the "first right-hand expected path".The left-hand expected path and the right-hand expected path with a line segment shape are referred to below as the "second left-hand expected path" and the "second right-hand expected path," respectively. A procedure for estimating the first left-hand expected path and the first right-hand expected path is described below, followed by a procedure for estimating the second left-hand expected path and the second right-hand expected path. 1. Estimation of the first left-hand expected path and the first right-hand expected path: 1-1. Calculation of the curve radius R

[0059] As in Fig. As shown in Figure 4A, when the driving assistance ECU 10 determines that the reference vehicle 100 is making a right turn or a left turn, the driving assistance ECU 10 estimates the first left-hand expected path (in Fig. 4A (represented by a bold line) in the nth cycle in the xy-coordinate plane as part of a formula of a first left-hand expected path fL1(n) (described below), which is a formula of a circle, and estimates the first right-hand expected path (represented by a bold line in Fig. (4A shown) in the nth cycle as part of a formula for a first right-hand expected path fR1(n) (described below), which is a formula for a circle. The driving assistance ECU 10 calculates the mean coordinates and radii of the circles based on a curve radius R(n), which is the radius of a circle that is expected to pass through the origin O(n) of the reference vehicle 100. The curve radius R(n) is calculated, for example, by dividing the vehicle speed SPDv(n) by |Ys(n)|, which is the order of magnitude or absolute value of the uniform yaw rate Ys(n) (that is, R(n) = SPDv(n) / |Ys(n)|). A detailed method for obtaining R(n) is also disclosed in the applicant's Japanese patent application number JP 2016-224957A. 1-2. Calculation of the formula for the first left-hand expected path fL1 and the formula for the first right-hand expected path fR1

[0060] The driving assistance ECU 10 calculates the mean coordinates (Cx(n), Cy(n)) and a left-hand curve radius RL(n) of the circle represented by the formula of a first left-hand expected path fL1(n), using a general formula (8) up to the general formula (11) described below, based on the curve radius R(n) calculated in 1-1. The driving assistance ECU 10 calculates the formula of a first left-hand expected path fL1(n), represented by the general formula (12), using the mean coordinates (Cx(n), Cy(n)) and the left-hand curve radius RL(n).Similarly, the vehicle assistance ECU 10 calculates the center coordinates (Cx(n), Cy(n)) and a right-hand curve radius RR(n) of the circle represented by the formula of a first right-hand expected path fR1(n), using general formulas (13) to (16) described below, based on the curve radius R(n) calculated in 1-1. The vehicle assistance ECU 10 calculates the formula of a first right-hand expected path fR1(n), represented by general formula (17), using the center coordinates (Cx(n), Cy(n)) and the right-hand curve radius RR(n). The width (the length in the y-axis direction) of the reference vehicle 100 is denoted by w [m]. The width w is preset for each vehicle in which the vehicle assistance ECU 10 is installed.

[0061] Mean coordinates (Cx(n), Cy(n)) for the formula of the first left-hand expected path fL1(n): (Left curve)(Cx(n),Cy(n))=(0,R(n)) (Right turn)(Cx(n),Cy(n))=(0,−R(n))

[0062] Left-hand curve radius RL(n) of the form of the first left-hand expected path fL1(n): (Left turn)RL(n)=R(n)−w / 2 (Right turn)RL(n)=R(n)+w / 2

[0063] Formula of a first left-hand expected path fL1(n): (x(n)−Cx(n))2+(y(n)−Cy(n))2=RL(n)2

[0064] Mean coordinates (Cx(n), Cy(n)) of the formula of a first right-hand expected path fR1(n): (Left curve)(Cx(n),Cy(n))=(0,R(n)) (Right turn)(Cx(n),Cy(n))=(0,−R(n))

[0065] Right-hand curve radius RR(n) of the formula of a first right-hand expected path fR1(n): (Left turn)RR(n)=R(n)+w / 2 (Right turn)RR(n)=R(n)−w / 2

[0066] Formula of a first right-hand expected path fR1(n): (x(n)−Cx(n))2+(y(n)−Cy(n))2=RR(n)2

[0067] That is, the driving assistance ECU 10 calculates the mean coordinates (Cx(n), Cy(n)) of the formula of the first left-hand expected path fL1(n) on the y-axis (that is, a direction passing through the origin O(n) and orthogonal with respect to the direction of travel TDv(n) of the reference vehicle 100) as a point moved by the order of magnitude or absolute value of the curve radius R(n) in the positive direction of the y-axis from the origin O(n) when the reference vehicle 100 makes a left turn, and as a point moved by the order of magnitude of the curve radius R(n) in the negative direction of the y-axis from the origin O(n) when the reference vehicle 100 makes a right turn (see general formula (8) and general formula (9)).The driving assistance ECU 10 calculates the mean coordinates (Cx(n), Cy(n)) of the formula of the first right-hand expected path fR1(n) as the same point as the mean coordinates (Cx(n), Cy(n)) of the formula of the first left-hand expected path fL1(n) (see general formula (8), general formula (9), general formula (13), and general formula (14)).

[0068] The driving assistance ECU 10 calculates the left-hand curve radius RL(n) of the formula of the first left-hand expected path fL1(n) by subtracting half the length (half the vehicle width) w / 2 of the vehicle width w of the reference vehicle 100 from the curve radius R(n) when the reference vehicle 100 makes a left turn, and by adding half the vehicle width w / 2 to the curve radius R(n) when the reference vehicle 100 makes a right turn (see general formula (10) and general formula (11)). The driving assistance ECU 10 calculates the right-hand curve radius RR(n) of the formula of the first right-hand expected path fR1(n) by adding half the vehicle width w / 2 to the curve radius R(n) when the reference vehicle 100 makes a right turn, and by subtracting half the vehicle width w / 2 from the curve radius R(n) when the reference vehicle 100 makes a left turn (see general formula (15) and general formula (16)).The driving assistance ECU 10 stores the formulas of the first expected path fL1(n), fR1(n) in the RAM of the driving assistance ECU 10. 1-3. Calculation of the length LL1 of the first left-hand expected path and the length LR1 of the first right-hand expected path

[0069] The driving assistance ECU 10 calculates a length LL1(n) of the first left-hand expected path and a length LR1(n) of the first right-hand expected path by general formula (18) and general formula (19). LL1(n)=RL(n)⋅(90°−θtotal(n))⋅π / 180° LR1(n)=RR(n)⋅(90°−θtotal(n))⋅π / 180°

[0070] This means that the driving assistance ECU 10 calculates the length LL1(n) of the first left-hand expected path and the length LR1(n) of the first right-hand expected path as the length of an arc corresponding to a rotation angle formed by the reference vehicle 100 before the left turn or right turn is completed, at a location where the reference vehicle 100 makes the left turn or right turn at the instantaneous time (that is, 90° - θtotal(n)). The driving assistance ECU 10 stores the length LL1(n) and the length LR1(n) of each first expected path in the RAM of the driving assistance ECU 10. 2. Estimation of the second left-hand expected path and the second right-hand expected path: 2-1: Calculation of a formula for a second left-hand expected path fL2 and a formula for a second right-hand expected path fR2

[0071] When the driving assistance ECU 10 determines that the reference vehicle 100 is traveling straight ahead, the driving assistance ECU 10 calculates a formula for a second left-hand expected path fL2(n) and a formula for a second right-hand expected path fR2(n) using general formula (20) and general formula (21). The formula for a second left-hand expected path fL2(n) includes a second left-hand expected path in the nth cycle in the xy-coordinate plane within a portion thereof. The formula for a second right-hand expected path fR2(n) includes a second right-hand expected path in the nth cycle in the xy-coordinate plane within a portion thereof.

[0072] Formula of the second left-hand expected path fL2(n): y=w / 2(x≥0)

[0073] Formula of the second right-hand expected path fR2(n): y=−w / 2(x≥0)

[0074] This means that the driving assistance ECU 10 calculates the formula of a second left-hand expected path fL2(n) as a formula of a semiline extending in the direction of travel TDv(n) of the reference vehicle 100 from the left end OL(n) of the reference vehicle 100. The driving assistance ECU 10 calculates the formula of a second right-hand expected path fR2(n) as a formula of a semiline extending in the direction of travel TDv(n) of the reference vehicle 100 from the right end OR(n) of the reference vehicle 100. The driving assistance ECU 10 stores the formulas of a second expected path fL2(n) and fR2(n) in the RAM of the driving assistance ECU 10. 2-2. Setting a length LL2 of a second left-hand expected path and a length LR2 of a second right-hand expected path

[0075] The driving assistance ECU 10 sets a length LL2(n) of the second left-hand expected path as the length (7m in this example) from the left end OL(n) of the reference vehicle 100 to a predetermined left-hand position (a point (w / 2,7) in this example), and sets a length LR2(n) of the second right-hand expected path as the length (7m in this example) from the right end OR(n) of the reference vehicle 100 to a predetermined right-hand position (a point (-w / 2,7) in this example). The driving assistance ECU 10 stores the length LL2(n) and the length LR2(n) of every second expected path in the RAM of the driving assistance ECU 10. Estimation of the object's expected path

[0076] The driving assistance ECU 10 estimates an expected path that the object is expected to follow, based on the object information. The driving assistance ECU 10 calculates a formula for an expected path g(n) as a formula for a semiline extending in the direction of travel TDo(n) of the object from the object's relative position P(n). The formula for an expected path g(n) represents the expected path of the object in the nth cycle in the xy-coordinate plane. A body A to a body C, which in Fig. 4A are shown, and a body D to a body H, which are in Fig. The physical bodies (i.e., objects) shown in Figure 4B are those present within the range of the electromagnetic wave transmitted by each radar sensor 15 of the reference vehicle 100 in the nth cycle. In the example in Fig. 4A and Fig. 4B, based on the object information in the nth cycle, calculates the driving assistance ECU 10 a formula for an expected path gd(n) up to a formula for an expected path gg(n), which accordingly leads from a driving direction TDoa(n) of object A up to a driving direction TDog(n) of object H (see arrows in Fig. 4A and Fig. 4B) extends from a relative position Pa(n) of object A to a relative position Pg(n) of object H (hereinafter, the formula of an expected path g(n) is simply referred to as a "formula g(n)"). The driving assistance ECU 10 stores the formula gg(n) up to the formula gg(n) in the RAM of the driving assistance ECU 10.

[0077] Determination condition when reference vehicle 100 makes a right turn or a left turn, and determination conditions when reference vehicle 100 travels straight ahead

[0078] A “determination condition when the driving assistance ECU 10 determines that the reference vehicle 100 is making a left turn or a right turn,” which is implemented by the driving assistance ECU 10, differs partially from a “determination condition when the driving assistance ECU 10 determines that the reference vehicle 100 is traveling straight ahead,” which is implemented by the driving assistance ECU 10. The determination condition when the driving assistance ECU 10 determines that the reference vehicle 100 is making a left turn or a right turn is described below, followed by the determination condition when the driving assistance ECU 10 determines that the reference vehicle 100 is traveling straight ahead. 3. If the driver assistance ECU 10 determines that the reference vehicle 100 is making a left turn or a right turn: 3-1. First intersection point condition and calculation of the coordinates of the intersection point Q1

[0079] When the driving assistance ECU 10 determines that the reference vehicle 100 is making a left turn or a right turn, the driving assistance ECU 10 determines whether a first intersection condition is met. The first intersection condition is that a line represented by the object's formula g(n) (any of the formulas ga(n) up to and including gc(n) in the examples provided) intersects at least one of the reference vehicle 100's first left-hand expected path and the first right-hand expected path. In this specification, "an intersection of two lines" means that one line crosses the other line and does not mean that two lines are connected. If the driving assistance ECU 10 determines that the first intersection condition is met, it extracts the object as one that satisfies the first intersection condition.In such a case, the driving assistance ECU 10 calculates the number of intersection points where the line represented by the formula g(n) intersects the first left-hand expected path and / or the first right-hand expected path. If the number of intersection points is two, the driving assistance ECU 10 calculates the coordinates of the intersection point Q1(n), where the line represented by the formula g(n) first intersects the first left-hand expected path or the first right-hand expected path in the object's direction of travel TDo(n). If the number of intersection points is one, the driving assistance ECU 10 calculates the coordinates of the intersection point Q1(n). If the driving assistance ECU 10 determines that the first intersection condition is not met, it does not extract the object.The driving support ECU 10 stores the extraction result and the coordinates of the intersection point Q1(n) in the RAM of the driving support ECU 10 in association with the object that has the intersection point Q1(n).

[0080] In the example in Fig. 4A: A line represented by the formula ga(n) for object A intersects with the first left-hand expected path, represented by a bold solid line, at point A1 and intersects with the first right-hand expected path, represented by a bold solid line, at point A2. Thus, the number of intersections is two. A line represented by the formula gb(n) for object B intersects with the first left-hand expected path at point B1. Thus, the number of intersections is one. Accordingly, the driving assistance ECU 10 determines that the first intersection condition is satisfied for both object A and object B and extracts object A and object B as the object that satisfies the first intersection condition.The driving assistance ECU 10 calculates the coordinates of point A1, which is the intersection point where the line represented by the formula ga(n) first intersects either the first left-hand expected path or the first right-hand expected path in the direction of travel TDoa(n) of object A, as the coordinates of an intersection point Q1a(n) for object A, and calculates the coordinates of intersection point B1 as the coordinates of an intersection point Q1b(n) for object B. A line represented by the formula gc(n) for object C does not intersect either the first left-hand expected path or the first right-hand expected path. Thus, the driving assistance ECU 10 determines that the first intersection condition is not met for object C and does not extract object C. 3-2. Calculation of the first time period t1

[0081] When the driving assistance ECU 10 extracts an object as the one that satisfies the first intersection condition, it calculates a first time period t1(n) in which the object is expected to reach either the first left-hand expected path or the first right-hand expected path. The driving assistance ECU 10 calculates this first time period t1(n) by dividing the length from the object's relative position P(n) to the intersection point Q1(n) by the object's velocity SPDo(n). The driving assistance ECU 10 stores this first time period t1(n) in its RAM associated with the object. In the example in Fig. 4A, the driving assistance ECU 10, calculates a first time period t1a(n) and a first time period t1b(n) accordingly for object A and object B, which are extracted as the object that satisfies the first intersection condition. The first time period t1a(n) is calculated by dividing the length from the relative position Pa(n) of object A to the intersection point Q1a(n) by a velocity SPDoa(n) of object A. The first time period t1b(n) is calculated using the same procedure. 4. If the driving assistance ECU 10 determines that the reference vehicle 100 is traveling straight ahead, 4-1. Second intersection condition and calculation of intersection point coordinates Q2

[0082] The driving assistance ECU 10 determines whether a second intersection condition is met. The second intersection condition is that the line represented by the object's formula g(n) (any of the formulas gd(n) up to gg(n) in this example) intersects both a line represented by the formula of a second left-hand expected path fL2(n) and a line represented by the formula of a second right-hand expected path fR2(n) of the reference vehicle 100. If the driving assistance ECU 10 determines that the second intersection condition is met, it extracts the object as one that satisfies the second intersection condition.The driving assistance ECU 10 calculates the coordinates of an intersection point Q2(n) of the line represented by formula g(n) of the extracted object and one of the lines represented by the formula of a second left-hand expected path fL2(n) and the formula of a second right-hand expected path fR2(n), with which the line represented by formula g(n) first intersects. If the driving assistance ECU 10 determines that the second intersection condition is not met, it does not extract the object. The driving assistance ECU 10 stores the extraction result and the coordinates of the intersection point Q2(n) in the RAM of the driving assistance ECU 10, associated with the object that has the intersection point Q2(n).As can be seen from the description, if the line represented by the formula g(n) of the object intersects with one of the two lines while the driving assistance ECU 10 determines that the reference vehicle 100 is traveling straight ahead (that is, if the relative position P(n) of the object, which has the direction of travel TDo(n) that intersects with the direction of travel TDv(n) of the reference vehicle 100, is positioned between these two lines), the intersection conditions are not met.

[0083] In the example in Fig. 4B A line represented by the formula ge(n) for object E intersects both lines represented by the formula of a second left-hand expected path fL2(n) and the formula of a second right-hand expected path fR2(n) of reference vehicle 100, and intersects the line represented by the formula of a second left-hand expected path fL2(n) for the first time at a point Q2e(n). A line represented by the formula gg(n) for object G intersects both lines represented by the formula of a second left-hand expected path fL2(n) and the formula of a second right-hand expected path fR2(n), and intersects the line represented by the formula of a second right-hand expected path fR2(n) for the first time at a point Q2g(n).Accordingly, the driving assistance ECU 10 determines that the second intersection condition is true for object E and object G and extracts object E and object G as the object that satisfies the second intersection condition. The driving assistance ECU 10 calculates the coordinates of the intersection point Q2e(n) for object E and calculates the coordinates of the intersection point Q2g(n) for object G. Lines represented by the formula gd(n) for object D, the formula gf(n) for object F, and the formula gh(n) for object H do not intersect with any of the lines represented by the formula of a second left-hand expected path fL2(n) and the formula of a second right-hand expected path fR2(n). Thus, the driving assistance ECU 10 determines that the second intersection condition is false for object D, object F, and object H and does not extract object D, object F, and object H. 4-2. Calculation of a distance d1 and a length condition

[0084] If the driving assistance ECU 10 extracts an object as the object that satisfies the second intersection condition, the driving assistance ECU 10 calculates a distance d1(n) [m] from the reference vehicle 100 to the intersection point Q2(n) for the object. If the intersection point Q2(n) is positioned on a left-hand expected path, the driving assistance ECU 10 calculates the distance d1(n) as the distance from the left end OL(n) of the reference vehicle 100 to the intersection point Q2(n). If the intersection point Q2(n) is positioned on a right-hand expected path, the driving assistance ECU 10 calculates the distance d1(n) as the distance from the right end OR(n) of the reference vehicle 100 to the intersection point Q2(n). The driving assistance ECU 10 stores the distance d1(n) in the RAM of the driving assistance ECU 10. The driving assistance ECU 10 determines whether a length condition is met or not.The length condition is that the distance d1(n) is less than or equal to the length of every second expected path of the reference vehicle 100 (7m in this example). If the driving assistance ECU 10 determines that the length condition is true, it extracts the object as one that satisfies the length condition. If it determines that the length condition is false, it does not extract the object. The driving assistance ECU 10 stores the extraction result in its RAM.

[0085] In the example in Fig. In 4B, where object E and object G are extracted as the object satisfying the second intersection condition, a distance d1e(n) for object E from the left end OL(n) of reference vehicle 100 to the intersection point Q2e(n) is less than or equal to the length of the second left-hand expected path (see a bold line in Fig. 4B). A distance d1g(n) for the object G from the right end OR(n) of the reference vehicle 100 to the intersection point Q2g(n) is less than or equal to the length of the second right-hand expected path (see a bold line in Fig. 4B). Accordingly, the driving assistance ECU 10 determines that the length condition applies to both objects E and G and extracts object E and object G as the object that satisfies the length condition. 4-3. Calculation of the second time period t2

[0086] When the driving assistance ECU 10 extracts an object as the one that satisfies the length condition, it calculates a second time period t2(n) in which the object is expected to reach the second left-hand expected path or the second right-hand expected path. The driving assistance ECU 10 calculates the second time period t2g(n) by dividing the length from the object's relative position P(n) to the intersection point Q2(n) by the object's velocity SPDo(n). The driving assistance ECU 10 stores the second time period t2(n) in its RAM associated with the object. In the example in Fig. 4B calculates the driving assistance ECU 10 a second time period t2e(n) and a second time period t2g(n) accordingly for object E and object G, which are extracted as the object that satisfies the length conditions. The second time period t2e(n) is calculated by dividing the length from a relative position Pe(n) of object E to the intersection point Q2e(n) by a velocity SPDoe(n) of object E. The second time period t2g(n) is calculated using the same procedure. Time period condition

[0087] When the driving assistance ECU 10 determines that the reference vehicle 100 is making a left turn or a right turn, or when the driving assistance ECU 10 determines that the reference vehicle 100 is traveling straight ahead, the driving assistance ECU 10 determines whether a time period condition is met. The time period condition is that the first time period t1(n) or the second time period t2(n) is less than or equal to a threshold time period (four seconds in this example). If the driving assistance ECU 10 determines that the time period condition is met, it extracts the object as one that satisfies the time period condition. If the driving assistance ECU 10 determines that the time period condition is not met, it does not extract the object. The driving support ECU 10 stores the extraction result in the RAM of the driving support ECU 10.

[0088] For example, if the first time period t1a(n) for object A is three seconds, and the first time period t1b(n) for object B is six seconds, Fig. If the first time period t1a(n) is less than or equal to the threshold time period, the driving assistance ECU 10 determines that the time period condition is met for object A and extracts object A as the object that satisfies the time period condition. If the first time period t1b(n) exceeds the threshold time period, the driving assistance ECU 10 determines that the time period condition is not met for object B and does not extract object B.

[0089] For example, if the second time period t2e(n) for object E is two seconds and the second time period t2g(n) for object G is five seconds in Fig. 4B, if the second time period t2e(n) is less than or equal to the threshold time period, the driving assistance ECU 10 determines that the time period condition is met for object E and extracts object E as the object that satisfies the time period condition. The second time period t2g(n) exceeds the threshold time period. Therefore, the driving assistance ECU 10 determines that the time period condition is not met for object G and does not extract object G. Setting the attentional arousal marker

[0090] If the driving assistance ECU 10 extracts an object as the object that satisfies the time period condition, the driving assistance ECU 10 determines that it is likely that the object will cross the first left-hand expected path and / or the first right-hand expected path, or the second left-hand expected path and / or the second right-hand expected path within the threshold time period (in other words, determines that the object is the target object), and sets the value of the attention arousal marker for the object to 1.If the driving assistance ECU 10 does not extract an object other than the object that satisfies the first intersection condition or the time period condition, while the driving assistance ECU 10 determines that the reference vehicle 100 is making a right turn or a left turn, the driving assistance ECU 10 determines that it is highly unlikely that the object will cross the first left-hand expected path and / or the first right-hand expected path within the threshold time period (in other words, determines that the object is not the target object), and sets the value of the attention arousal marker for the object to 0.If the driving assistance ECU 10 does not extract an object other than the one that satisfies the second interface condition, the length condition, or the time period condition, while the driving assistance ECU 10 determines that the reference vehicle 100 is traveling straight ahead, the driving assistance ECU 10 determines that it is highly unlikely that the object will cross the second left-hand expected path and / or the second right-hand expected path within the threshold time period and sets the value of the attention arousal marker for the object to 0. Hereafter, the first left-hand expected path and the second left-hand expected path may be collectively referred to as a "left-hand expected path." The first right-hand expected path and the second right-hand expected path may collectively be referred to as a "right-hand expected path."The driver assistance ECU 10 stores the value of the attention arousal marker, which is set for each object, in the RAM of the driver assistance ECU 10.

[0091] In the example in Fig. 4A sets the driving assistance ECU 10 to 1 for object A, which is extracted as the object that satisfies the time period condition. Driving assistance ECU 10 sets the driving assistance ECU 10 to 0 for object C, which is not extracted as the object that satisfies the first intersection condition, and for object B, which is not extracted as the object that satisfies the time period condition.

[0092] In the example in Fig. 4B The driving assistance ECU 10 sets the value of the attention arousal marker for object E, which is extracted as the object that satisfies the time period condition, to 1. The driving assistance ECU 10 sets the value of the attention arousal marker for object D, object F, and object H, which are not extracted as the object that satisfies the second intersection condition, to 0, and sets the value of the attention arousal marker for object G, which is not extracted as the object that satisfies the time period condition, to 0. C. Operation regarding the determination of the anterior space

[0093] Next, an operation concerning the determination of the frontal area is described. During the machine ON period, or each time the computation time period Tcal expires, the driving assistance ECU 10 determines whether an object being followed by the reference vehicle 100 is within a rectangular area of ​​a predetermined size that exists in front of the reference vehicle. Hereinafter, this rectangular area is referred to as the "frontal area." If the driving assistance ECU 10 determines that an object being followed by the reference vehicle 100 is within the frontal area, it determines that no space exists in front of the reference vehicle 100 that would allow the target object to pass in front of it, and sets the frontal area marker to 0. Hereinafter, the "space in front of the reference vehicle 100 that allows the target object to pass in front of it" is referred to as the "frontal area."If the driving assistance ECU 10 determines that an object being followed by the reference vehicle 100 is not within the front area, the driving assistance ECU 10 determines that the front area exists and sets the value of the front area marker to 1. In contrast to target object determination, front area determination performs the same process whether the driving assistance ECU 10 determines that the reference vehicle 100 is making a left turn or a right turn, or whether the driving assistance ECU 10 determines that the reference vehicle 100 is traveling straight ahead. Thus, a front area determination procedure is described in more detail below using an example where the driving assistance ECU 10 determines that the reference vehicle 100 is traveling straight ahead (see Figure 1). Fig. 5). Frontline presence requirement

[0094] The driving assistance ECU 10 determines whether an object is present in front of the reference vehicle 100, based on the object information. Specifically, the driving assistance ECU 10 determines whether a front presence condition is met. The front presence condition is that the value of the x-coordinate of the object's relative position P(n) is 0 ≤ x. If the driving assistance ECU 10 determines that the front presence condition is met, it determines that the object is present in front of the reference vehicle 100 and extracts the object as one that meets the front presence condition. If the driving assistance ECU 10 determines that the front presence condition is not met, it determines that the object is not present in front of the reference vehicle 100 and does not extract the object. The driving support ECU 10 stores the extraction result in the RAM of the driving support ECU 10.

[0095] In the example in Fig. In scenario 5, where object D is present up to object H around reference vehicle 100, the x-coordinate from any relative position Pe(n) of object E to a relative position Ph(n) of object H has a positive value. Accordingly, the driving assistance ECU 10 determines that the front presence condition is met for object E up to object H and extracts object E up to object H as the object that satisfies the front presence condition. The x-coordinate of a relative position Pd(n) of object D has a negative value. Thus, the driving assistance ECU 10 determines that the front presence condition is not met for object D and does not extract object D. Forward and backward distance condition

[0096] When the driving assistance ECU 10 extracts an object as the object that satisfies the front presence condition, the driving assistance ECU 10 determines whether a forward and backward distance d2(n) [m] is equal to or less than a predetermined forward and backward distance threshold (6 m in this example) based on the object information of the extracted object. The forward and backward distance d2(n) is the distance from the reference vehicle 100 to the extracted object in a forward-backward direction (i.e., the x-axis direction). Specifically, the driving assistance ECU 10 determines whether a forward and backward distance condition is met. The forward and backward distance condition is that the value of the x-coordinate of the relative position P(n) of the object is 0 ≤ x ≤ 6.If the driving assistance ECU 10 determines that the forward and backward distance condition is met, it determines that the forward and backward distance d2(n) of the reference vehicle 100 to the extracted object is less than or equal to the forward and backward distance threshold and extracts the object as one that meets the forward and backward distance condition. If the driving assistance ECU 10 determines that the forward and backward distance condition is not met (that is, if the driving assistance ECU 10 determines that the value of the x-coordinate of the relative position P(n) of object 6 < x), it determines that the forward and backward distance d2(n) from the reference vehicle 100 to the extracted object is greater than the forward and backward distance threshold and does not extract the object.The driving assistance ECU 10 stores the extraction result in the RAM of the driving assistance ECU 10. The forward and reverse distance threshold is set such that it is less than or equal to the lengths of the second left-hand expected path and the second right-hand expected path of the reference vehicle 100 (7 m in the present example).

[0097] In the example in Fig. 5, in which object E up to object H is extracted as the object that satisfies the front presence conditions, the value of the x-coordinate from any of the relative positions Pe(n) of object E up to the relative position Pg(n) of object G satisfies 0 ≤ x ≤ 6. Accordingly, the driving assistance ECU 10 determines that the forward and backward distance condition is satisfied for object E up to object G and extracts object E up to object G as the object that satisfies the forward and backward distance condition. The value of the x-coordinate of the relative position Ph(n) of object H satisfies 6 < x. Thus, the driving assistance ECU 10 determines that the forward and backward distance condition is not satisfied for object H and does not extract object H. Horizontal spacing condition

[0098] When the driving assistance ECU 10 extracts an object as the one that satisfies the forward and backward distance condition, the driving assistance ECU 10 determines whether a horizontal distance d3(n) [m] is equal to or less than a predetermined horizontal distance threshold (2 m in this example) based on the object information of the extracted object. The horizontal distance d3(n) is the distance from the reference vehicle 100 to the extracted object in the horizontal direction (i.e., the y-axis direction). Specifically, the driving assistance ECU 10 determines whether a horizontal distance condition is met. The horizontal distance condition is that the absolute value of the y-coordinate of the relative position P(n) of the object is less than or equal to 2.If the driving assistance ECU 10 determines that the horizontal distance condition is met, it determines that the horizontal distance d3(n) from the reference vehicle 100 to the extracted object is less than or equal to the horizontal distance threshold and extracts the object as one that meets the horizontal distance condition. If the driving assistance ECU 10 determines that the horizontal distance condition is not met (that is, if the driving assistance ECU 10 determines that the absolute value of the y-coordinate of the relative position P(n) of the object is greater than 2), it determines that the horizontal distance d3(n) from the reference vehicle 100 to the extracted object is greater than the horizontal distance threshold and does not extract the object. The driving assistance ECU 10 stores the extraction result in its RAM.By determining whether each of the front presence condition, the forward and backward distance condition and the horizontal distance condition is true or not, the driving assistance ECU 10 can determine whether an object is present or not within a rectangular area in front of the reference vehicle 100 (i.e. the front area) and satisfies 0 ≤ x ≤ 6 and -2 ≤ y ≤ 2.

[0099] In the example in Fig. In example 5, where object E is extracted up to object G as the object that satisfies the forward and backward distance condition, the absolute value of the y-coordinate of a relative position Pf(n) of object F is less than or equal to 2. Accordingly, the driving assistance ECU 10 determines that the horizontal distance condition is met for object F and extracts object F as the object that satisfies the horizontal distance condition. The absolute value of the y-coordinate of the relative position Pe(n) of object E and the absolute value of the y-coordinate of the relative position Pg(n) of object G are greater than 2. Thus, the driving assistance ECU 10 determines that the horizontal distance condition is not met for object E and object G and does not extract object E and object G. That is, in the example in Fig. 5 determines that the driving assistance ECU 10 is present in the front area. Horizontal velocity condition

[0100] When the driving assistance ECU 10 extracts an object as the one that satisfies the horizontal distance condition, the driving assistance ECU 10 determines whether the object's direction of travel TDo(n) is approximately parallel to the direction of travel TDv(n) of the reference vehicle 100, based on the object information of the extracted object. Specifically, the driving assistance ECU 10 determines whether a horizontal velocity condition is met. The horizontal velocity condition is that the object's horizontal directional velocity (hereinafter referred to as a "horizontal velocity") SPDoy(n) is less than or equal to a predetermined horizontal velocity threshold (5 km / h in this example).The horizontal velocity SPDoy(n) of the object is calculated as the y-component of a velocity vector of the object, which has a magnitude of the object's velocity SPDo(n) and a direction corresponding to the object's direction of travel TDo(n). If the driving assistance ECU 10 determines that the horizontal velocity condition is true (that is, if the driving assistance ECU 10 determines that SPDoy(n) ≤ 5 is satisfied), the driving assistance ECU 10 determines that the object's direction of travel TDo(n) is approximately parallel to the direction of travel TDv(n) of the reference vehicle 100 and extracts the object as an approximately parallel object that satisfies the horizontal velocity condition.If the driving assistance ECU 10 determines that the horizontal velocity condition is not met (that is, if the driving assistance ECU 10 determines that 5 < SPDoy(n) is satisfied), the driving assistance ECU 10 determines that the object's direction of travel TDo(n) intersects with the direction of travel TDv(n) of the reference vehicle 100 and does not extract the object. The driving assistance ECU 10 stores the extraction result in its RAM.

[0101] If an object present in the frontal area is one that crosses the frontal area at a comparatively high speed, the object passes the frontal area in a comparatively short time period. Thus, the object could not be the object that the reference vehicle 100 is following. The object is considered to be an object that attracts attention if the target object enters the frontal area ahead of the object. However, in a determination of the frontal presence condition, the forward and backward distance condition, and the horizontal distance condition, all objects determined to be present in the frontal area are extracted as the objects that satisfy each condition, and the extracted objects include an object that crosses the frontal area at a comparatively high speed.Thus, by determining whether the horizontal velocity condition is met or not, an object crossing the front area at a horizontal velocity greater than the horizontal velocity threshold can be excluded from the objects determined to be present in the front area (not set as a target for extraction). Accordingly, the driving assistance ECU 10 can extract an object present in the front area with a horizontal velocity SPDoy(n) less than or equal to the horizontal velocity threshold (that is, the approximately parallel objects; in other words, an object that is comparatively likely to be tracked by the reference vehicle 100).

[0102] In the example in Fig. 5. It is assumed that the horizontal velocity SPDoy(n) of object F, extracted as the object satisfying the horizontal distance condition, is equal to 0 km / h. In such a case, the driving assistance ECU 10 determines that the horizontal velocity condition is true for object F and extracts object F as the approximately parallel object satisfying the horizontal velocity condition. Setting a tracking marker

[0103] If the driving assistance ECU 10 extracts an object as the approximately parallel object that satisfies the horizontal velocity condition, the driving assistance ECU 10 determines that the approximately parallel object is being tracked by the reference vehicle 100 within the front area of ​​the reference vehicle 100 and sets the value of a tracking marker for the approximately parallel object to 1. Hereafter, the “object that the reference vehicle 100 is tracking” is referred to as a “tracked object.” If the driving assistance ECU 10 does not extract an object as the object that satisfies the front presence condition, the forward and backward distance condition, the horizontal distance condition, or the horizontal velocity condition, the driving assistance ECU 10 determines that the object is not the tracked object and sets the value of the tracking marker for the object to 0.The driving assistance ECU 10 stores the value of the tracking marker, which is set for each object, in the RAM of the driving assistance ECU 10.

[0104] In the example in Fig. 5. The driving assistance ECU 10 sets the tracking marker value for object F, extracted as the object that meets the horizontal velocity condition, to 1. The driving assistance ECU 10 sets the tracking marker value for each of the following objects: object D, extracted as the object that meets the front presence condition; object H, extracted as the object that meets the forward and backward distance condition; and object E and object G, extracted as the object that meets the horizontal distance condition, to 0. Front area marker setting

[0105] When the driving assistance ECU 10 sets the tracking marker value by determining whether each of the conditions described above applies to all objects surrounding the reference vehicle 100, the driving assistance ECU 10 determines whether an object with a tracking marker value set to 1 is present (that is, whether the tracked object is within the front area). If the driving assistance ECU 10 determines that an object with a tracking marker value of 1 is present (that is, the tracked object is within the front area), the driving assistance ECU 10 determines that there is no front area (that is, a space in front of the reference vehicle 100 that would allow the target object to pass in front of the reference vehicle 100) and sets the front area marker value to 0.If the driving assistance ECU 10 determines that an object whose tracking marker value is 1 does not exist (that is, the tracked object is not within the front area), the driving assistance ECU 10 determines that the front area exists and sets the value of the front area marker to 1. The driving assistance ECU 10 stores the set value of the front area marker in its RAM.

[0106] In the example in Fig. 5. The driving assistance ECU 10 sets the tracking marker by determining whether each of the conditions described above applies to object D up to object H, which are all objects present around vehicle 100. Then, the driving assistance ECU 10 determines whether an object with a tracking marker value of 1 is present. As described above, the tracking marker value of object F is 1. Therefore, the driving assistance ECU 10 determines that there is no front space in the front area and sets the value of the front space marker to 0. D. Operation regarding the determination of attention arousal

[0107] Next, an operation concerning attention arousal determination is described. During the machine-ON period, or each time the computation time period Tcal elapses, the driving assistance ECU 10 determines whether or not attention should be aroused for each object, based on the determination result of the target object determination in B (i.e., the value of the attention arousal marker) and the determination result of the front space determination in C (i.e., the value of the front space marker). The attention arousal determination is described in detail below. During the machine-ON period, the driving assistance ECU 10 determines whether or not attention should be aroused, even if the vehicle speed SPDv of the reference vehicle 100 is zero. When attention needs to be attracted

[0108] Specifically, if the driving assistance ECU 10 determines that the value of the attention arousal marker of any object is equal to 1 and the value of the front space marker of the object is equal to 1, the driving assistance ECU 10 determines that, “since the target object is present and there is a front space, the object passes through the front space and consequently crosses the left-side expected path and / or the right-side expected path of the reference vehicle 100”, generates the request signal and draws attention to the target object using the display device 21. When attracting attention is prohibited

[0109] If the driving assistance ECU 10 determines that the value of the attention arousal marker of any object is equal to 1 and that the value of the object's front space marker is equal to 0, the driving assistance ECU 10 determines that, "since there is no front space, although the target object is present, it is highly unlikely that the target object will cross the left-side expected path and / or the right-side expected path of the reference vehicle 100", prohibits the generation of the request signal and accordingly prohibits drawing attention to the target object. If attention is not attracted

[0110] If the driving assistance ECU 10 determines that the value of the attention arousal marker for all objects is 0, the driving assistance ECU 10 determines that the target object is not present (that is, the object is not the target object), regardless of the value of the front space marker, does not generate the request signal and accordingly does not arouse attention. Specific operation of the device embodied herein

[0111] Next, a specific operation of the device embodied here will be described. During the machine-ON period, the CPU of the drive support ECU 10 of the device embodied here executes routines that are shown in the flowcharts in Fig. 6 to Fig. Figure 8 shows that the CPU shuts down each time the calculation period Tcal expires. Hereinafter, the CPU of the driver assistance ECU 10 will simply be referred to as a "CPU".

[0112] When a predetermined time is reached, the CPU starts a process at step 600. Fig. 6 and performs the processes of step 602 and step 604 in that order.

[0113] Step 602: The CPU obtains the reference vehicle information (the vehicle speed SPDv(n), the yaw rate Y(n) and similar) from the reference vehicle 100, as described above, and stores the reference vehicle information in the RAM of the driving assistance ECU 10.

[0114] Step 604: The CPU determines the direction of travel TDv(n) of the reference vehicle 100 based on the reference vehicle information obtained in step 602. The CPU sets the coordinate axes (the x-axis and the y-axis) as described above and stores information representing the coordinate axes in the RAM of the driving assistance ECU 10.

[0115] Next, the CPU proceeds to step 606 and determines whether an object is present around the reference vehicle 100. If the CPU determines that an object is not present, it makes a determination of "No" in step 606, proceeds to step 628, and temporarily terminates the current routine. If the CPU determines that an object is present, it makes a determination of "Yes" in step 606 and proceeds to the following step 608.

[0116] Step 608: The CPU obtains the object information of the object (the coordinates of the relative position P(n), the direction of travel TDo(n) and the speed SPDo(n) of the object) as described above, and stores the object information in the RAM of the driving assistance ECU 10 (see general formula (4) and general formula (5)).

[0117] Next, the CPU proceeds to step 610 and performs the target object determination process. Then, the CPU proceeds to step 612 and performs the front area determination process. The CPU can perform step 610 after performing step 612, or it can perform step 612 concurrently with step 610.

[0118] In the routine in Fig. In step 610, the CPU executes the routine shown in the flowchart. Fig. Figure 7A is shown. When the CPU transitions to step 610, the CPU starts from a process of step 700 in Fig. 7A and performs a subsequent process from step 701.

[0119] In the routine in Fig. In step 701, the CPU estimates the "first left-hand expected path and first right-hand expected path" or the "second left-hand expected path and second right-hand expected path," as described above, by executing the routine shown in the flowchart in Fig. 7B is shown. This means that when the CPU moves to step 701, the CPU starts a process from step 702 in Fig. 7B and proceeds to the following step 703.

[0120] In step 703, the CPU determines whether the left turn start condition is met or not, based on the reference vehicle information obtained in step 602. Fig. 6. If the CPU determines that the left turn start condition is true, the CPU makes a determination of "Yes" in step 703 (that is, determines that the reference vehicle 100 begins to make a left turn) and performs processes from the following steps 704 and 706 in that order.

[0121] Step 704: The CPU initializes the total rotation angle θ to 0° (see general formula (6)). The total rotation angle θ is initialized once when the left turn start condition is met, and is then not initialized until the reference vehicle 100 completes the left turn.

[0122] Step 706: The CPU calculates the rotation angle θtotal(n) of the reference vehicle 100 from the m-th cycle to the n-th cycle as described above (see general formula (7)) and stores the rotation angle θtotal(n) in the RAM of the driving assistance ECU 10.

[0123] Next, the CPU proceeds to step 708 and determines whether the rotation angle θtotal(n), calculated in step 706, satisfies θtotal(n) ≤ 90°. If the CPU determines that θtotal(n) ≤ 90°, it makes a "Yes" determination in step 708 (that is, determines that the reference vehicle 100 makes a left turn) and executes the processes from step 710 to step 714 in that order. If the CPU determines that the rotation angle θtotal(n) > 90° is satisfied, the CPU makes a "No" determination in step 708 (that is, determines that the reference vehicle 100 completes the left turn and continues straight ahead) and proceeds to step 726 as described below.

[0124] Step 710: The CPU calculates the curve radius R(n) using the procedure described above and stores the curve radius R(n) in the RAM of the driver assistance ECU 10.

[0125] Step 712: The CPU calculates the mean coordinates (Cx(n), Cy(n)) (see general formula (8) and general formula (13)), the left-hand curve radius RL(n) (see general formula (10)) and the right-hand curve radius RR(n) (see general formula (15)), as described above, based on the curve radius R(n) calculated in step 710. The CPU calculates the formula of the first left-hand expected path fL1(n) and the formula of the first right-hand expected path fR1(n) using the mean coordinates (Cx(n), Cy(n)), the left-hand curve radius RL(n) and the right-hand curve radius RR(n) (see general formula (12) and general formula (17)) and stores the formula of a first left-hand expected path fL1(n) and the formula of a first right-hand expected path fR1(n) in the RAM of the driving assistance ECU 10.

[0126] Step 714: The CPU calculates the length LL1(n) of the first left-hand expected path based on the rotation angle θtotal(n) calculated in step 706 and the left-hand curve radius RL(n), calculated based on the curve radius R(n) calculated in step 710 (see general formula (18)). The CPU calculates the length LR1(n) of the first right-hand expected path based on the rotation angle θtotal(n) calculated in step 706 and the right-hand curve radius RR(n), calculated based on the curve radius R(n) calculated in step 710 (see general formula (19)). The CPU stores the formula for the first left-hand expected path fL1(n) and the formula for the first right-hand expected path fR1(n) in the RAM of the driver assistance ECU 10. When the CPU completes the process of step 714, it proceeds to step 730. Fig. 7A via step 729.

[0127] If the CPU determines that the left curve start condition is not true at a time when the CPU is executing the process of step 703, the CPU makes a "No" determination in step 703 and proceeds to step 716 below. The CPU makes a "No" determination in step 703 in the following cases. • The CPU performs the determination of step 703 after the CPU determines that the left turn start condition is true for the first time after the previous left turn or the previous right turn has been determined to be complete. • The left turn start condition does not apply after the CPU determines that the previous left turn or the previous right turn has ended.

[0128] Assume that the CPU performs the determination of step 703 after determining that the left turn start condition is met for the first time after the previous left turn or right turn is determined to be complete, and that the CPU consequently makes a "No" determination in step 703. Furthermore, assume that the driver intends to start a left turn and thus keeps the left indicator in the flashing state. In such a case, the CPU makes a "Yes" determination in step 716 and proceeds to step 706 as described above. When the CPU completes the process of step 706, it performs the processes of steps 708 through 714 as described above in that order and then proceeds to step 730. Fig. 7A via step 729.

[0129] If the left curve start condition is not met once while the left indicator is not in the blinking state after the previous left curve or the previous right curve is determined to be complete (No in step 703), or if the CPU performs the determination of step 703 after determining that the left curve start condition is met for the first time after the previous left curve or the previous right curve is determined to be complete, and consequently makes a determination of "No" in step 703 while the left indicator is not in the blinking state, the CPU makes a determination of "No" in step 716 and proceeds to step 718.

[0130] In step 718, the CPU determines whether the right turn start condition is met or not, based on the reference vehicle information obtained in step 602. Fig. 6. If the CPU determines that the right turn start condition is true, the CPU makes a determination of "Yes" in step 718 (that is, determines that the reference vehicle 100 starts a right turn) and performs processes from the following steps 720 and 722 in that order.

[0131] Step 720: The CPU performs the same process as in step 704. The CPU initializes the total rotation angle θ to 0° (see general formula (6)). The total rotation angle θ is initialized once when the right turn start condition is met, and is then not initialized until the reference vehicle 100 completes the right turn.

[0132] Step 722: The CPU performs the same process as in step 706. The CPU calculates the rotation angle θtotal(n) of the reference vehicle 100 (see general formula (7)) and stores the rotation angle θtotal(n) in the RAM of the driving assistance ECU 10.

[0133] Next, the CPU proceeds to step 708 and determines whether the rotation angle θtotal(n), calculated in step 722, satisfies the condition θtotal(n) ≤ 90°. If the CPU determines that θtotal(n) ≤ 90°, it makes a "Yes" determination in step 708 (that is, it determines that the reference vehicle 100 makes a right turn) and executes the processes from step 710 to step 714 in that order. If the CPU determines that the rotation angle θtotal > 90°, it makes a "No" determination in step 708 (that is, it determines that the reference vehicle 100 completes the right turn and continues straight ahead) and proceeds to step 726 as described below.

[0134] Step 710: The CPU calculates the curve radius R(n) using the procedure described above and stores the curve radius R(n) in the RAM of the driver assistance ECU 10.

[0135] Step 712: The CPU calculates the mean coordinates (Cx(n), Cy(n)) (see general formula (9) and general formula (14)), the left-hand curve radius RL(n) (see general formula (11)) and the right-hand curve radius RR(n) (see general formula (16)), as described above, based on the curve radius R(n) calculated in step 710. The CPU calculates the formula of a first left-hand expected path fL1(n) and the formula of a first right-hand expected path fR1(n), which are formulas of circles, using the mean coordinates (Cx(n), Cy(n)), the left-hand curve radius RL(n) and the right-hand curve radius RR(n) (see general formula (12) and general formula (17)) and stores the formula of the first left-hand expected path fL1(n) and the formula of the first right-hand expected path fR1(n) in the RAM of the driving assistance ECU 10.

[0136] Step 714: The CPU calculates the length LL1(n) of the first left-hand expected path and the length LR1(n) of the first right-hand expected path (see general formula (18) and general formula (19)) and stores the length LL1(n) and the length LR1(n) in the RAM of the driver assistance ECU 10. When the CPU completes the process of step 714, the CPU proceeds to step 730 in Fig. 7A via step 729.

[0137] If the CPU determines that the right-curve start condition is not true at a time when the CPU is executing the process of step 718, the CPU makes a "No" determination in step 718 and proceeds to step 724 below. If the CPU makes a "No" determination in step 718, the CPU makes a "No" determination in step 716 described above, and the following states occur: • The CPU performs the determination of step 718 after the CPU determines that the right turn start condition is true for the first time after the previous left turn or the previous right turn is determined to be complete. • The right turn start condition fails once after the CPU determines that the previous left turn or the previous right turn has ended.

[0138] Assume that the CPU performs the determination of step 718 after determining that the right turn start condition is met for the first time after the preceding left turn or right turn is determined to be complete, and that the CPU consequently makes a "No" determination in step 718. Furthermore, assume that the driver intends to start a right turn and thus keeps the right indicator in the flashing state. In such a case, the CPU makes a "Yes" determination in step 724 and proceeds to step 722 as described above. When the CPU completes the process of step 722, it performs the processes from step 708 to step 714, as described above, in that order and then proceeds to step 730. Fig. 7A via step 729.

[0139] If the right turn start condition is not met once while the right indicator is not in the blinking state after the preceding left turn or the preceding right turn is determined to be complete (No in step 718), or if the CPU makes the determination of step 718 after determining that the right turn start condition is met for the first time after the preceding left turn or the preceding right turn is determined to be complete, and consequently makes a determination of "No" in step 718 while the right indicator is not in the blinking state, the CPU makes a determination of "No" in step 724 (that is, the CPU determines that the reference vehicle 100 is traveling straight ahead) and performs processes from step 726 below in step 728 in that order.

[0140] Step 726: The CPU calculates the formula of a second left-hand expected path fL2(n) and a formula of a second right-hand expected path fR2(n), which are formulas of half-lines as described above (see general formula (20) and general formula (21)) and stores the formula of a second left-hand expected path fL2(n) and the formula of a right-hand expected path fR2(n) in the RAM of the driving assistance ECU 10.

[0141] Step 728: The CPU sets each of the lengths LL2(n) of the second left-hand expected path and LR2(n) of the second right-hand expected path to 7 m and stores the lengths LL2(n) and LR2(n) in the RAM of the driver assistance ECU 10. When the CPU completes the process of step 728, the CPU proceeds to step 730 in Fig. 7A via step 729.

[0142] When the CPU reaches step 730 in Fig. When step 7A is skipped, the CPU selects an object from the objects with the object information specified in step 608. Fig. The CPU retrieves the six acquired objects and estimates the expected path from the selected object in the xy-coordinate plane (in other words, it calculates the expected path formula g(n)). The CPU stores the expected path formula g(n) in the RAM of the driving assistance ECU 10 associated with the object. The CPU then performs the processes from step 730 to step 754, described below, for each selected object (see step 756, which is described below).

[0143] Next, the CPU proceeds to step 732 and determines whether the reference vehicle 100 is making a left turn or a right turn, based on the determination result of step 703, step 716, step 718 and / or step 724 in Fig. 7B. If the CPU determines that the reference vehicle 100 is making a left turn or a right turn, the CPU makes a determination of “Yes” in step 732 and proceeds to step 734.

[0144] In step 734, the CPU determines whether the first intersection condition is true for the object selected in step 730. If the CPU determines that the first intersection condition is true, it makes a "Yes" determination in step 734 and then executes the processes of steps 736 and 738 in that order.

[0145] Step 736: For the object for which the CPU determines in step 734 that the first intersection condition is true, the CPU calculates the coordinates of the intersection point Q1(n) at which the line represented by the formula g(n) intersects with the first left-hand expected path or the first right-hand expected path with an arc-shaped form, and stores the coordinates in the RAM of the driving assistance ECU 10 associated with the object.

[0146] Step 738: As described above, the CPU calculates the first time period t1(n) in which the object is expected to reach the intersection point Q1(n) and stores this first time period t1(n) in the RAM of the driving assistance ECU 10 in association with the object. The CPU then proceeds to step 750 as described below.

[0147] If the CPU determines that the reference vehicle 100 is not making a left or right turn, at a time when the CPU is executing the process of step 732 (that is, when the CPU determines that the reference vehicle 100 is going straight ahead), the CPU makes a determination of "No" in step 732 and proceeds to step 740.

[0148] In step 740, the CPU determines whether the second intersection condition is true for the object selected in step 730. If the CPU determines that the second intersection condition is true, it makes a "Yes" determination in step 740 and then executes the processes of steps 742 and 744 in that order.

[0149] Step 742: For the object for which the CPU determines in step 740 that the second intersection condition is true, the CPU calculates the coordinates of the intersection point Q2(n) of the line represented by the formula g(n) and one of the lines represented by the formula of a second left-hand expected path fL2(n) and the formula of a second right-hand path fR2(n) with a linear form, with which the line represented by the formula g(n) first intersects, and stores the coordinates in the RAM of the driving assistance ECU 10 associated with the object.

[0150] Step 744: The CPU calculates the distance d1(n) from the reference vehicle 100 to the intersection point Q2(n) calculated in step 742, and stores the distance d1(n) in the RAM of the driving assistance ECU 10 in association with the object.

[0151] Next, the CPU proceeds to step 746 and, using the distance d1(n) calculated in step 744, determines whether the length condition (d1(n) ≤ length of every second expected path (7 m in this example)) is true for the object for which the CPU determines in step 740 that the second intersection condition is true. If the CPU determines that the length condition is true, it makes a "Yes" determination in step 746 and executes the process in step 748 below.

[0152] Step 748: As described above, the CPU calculates the second time period t2(n) in which the object is expected to reach the intersection point Q2(n) and stores this second time period t2(n) in the RAM of the driving assistance ECU 10 in association with the object. The CPU then proceeds to step 750 below.

[0153] When the CPU proceeds to step 750, after calculating the first time period t1(n) in step 738, it determines whether the time period condition (t1(n) ≤ threshold time period (4 s in this example)) is true for the object for which the CPU determined in step 734 that the first intersection condition is true. When the CPU proceeds to step 750, after calculating the second time period t2(n) in step 748, it determines whether the time period condition (t2(n) ≤ threshold time period (4 s in this example)) is true for the object for which the CPU determined in step 746 that the length condition is true. In both cases, if the CPU determines that the time period condition is true, the CPU makes a determination of "Yes" in step 750 and performs a process from step 752 below.

[0154] Step 752: The CPU sets the value of the attention marker for the object to 1 and stores the set value in the RAM of the driver assistance ECU 10 in association with the object. The CPU then proceeds to step 756 as described below.

[0155] If in step 734 the CPU determines that the first intersection condition is not true, or if in step 750 the CPU determines that the time period condition is not true, the CPU determines that the object is not approaching from the left or right side of the reference vehicle 100 (in other words, the CPU determines that it is highly unlikely that the object will cross the first left-hand expected path and / or the first right-hand expected path with an arc shape within the threshold time period), makes a "No" determination in either step 734 or step 750, and performs a process of step 754 as described below.

[0156] If the CPU determines in step 740 that the second intersection condition is not true, if the CPU determines in step 746 that the length condition is not true, or if the CPU determines in step 750 that the time period condition is not true, the CPU also determines that the object is not approaching from the left or right side of the reference vehicle 100 (in other words, the CPU determines that it is highly unlikely that the object will cross the second left-hand expected path and / or the second right-hand expected path with a line segment shape within the predetermined time period), makes a determination of "No" in any of step 740, step 746, and step 750, and performs a process of step 754 below.

[0157] Step 754: The CPU sets the value of the attention arousal marker for the processed object (i.e., the object selected in step 730) to 0 and stores the set value in the RAM of the driver assistance ECU 10 associated with the object. The attention arousal marker is provided for each object (every object selected in step 730). The CPU then proceeds to step 756 below.

[0158] In step 756, the CPU determines whether the processes from step 730 described above should be executed for all objects with object information that was entered in step 608. Fig. 6 were procured, have been executed. If the CPU determines that the processes described above have not been executed for all objects, the CPU makes a determination of "No" in step 756, returns to step 730, and repeats the processes of step 730 for the remaining objects. If the CPU determines that the processes described above have been executed for all objects, the CPU makes a determination of "Yes" in step 756 and proceeds to step 612 in Fig. 6 about step 758.

[0159] When the CPU moves to step 612, it performs the frontal area determination by executing the steps shown in the flowchart. Fig. The routine shown in step 8 is executed. That is, when the CPU moves to step 612, the CPU starts a process from step 800 in... Fig. 8 and proceeds to the following step 801.

[0160] In step 801, the CPU selects any object from the objects with the object information specified in step 608. Fig. The CPU retrieves the 6 objects and determines whether the front presence condition (the value of the x-coordinate of the relative position P(n) of the object satisfies 0 ≤ x) is true or not, based on the object information of the selected object. If the CPU determines that the front presence condition is true, the CPU makes a "Yes" determination in step 801 and proceeds to step 802 below. The CPU performs appropriate processes from step 801 to step 810, described below, for each selected object (see step 812 described below).

[0161] In step 802, for the object for which the CPU determines in step 801 that the front presence condition is true, the CPU determines whether the forward and backward distance condition (the value of the x-coordinate of the object's relative position P(n) satisfies 0 ≤ x ≤ 6) is true or not, based on the object's information. If the CPU determines that the forward and backward distance condition is true, it makes a "Yes" determination in step 802 and proceeds to step 804 below.

[0162] In step 804, for the object for which the CPU determines in step 802 that the forward and backward distance condition is true, the CPU determines whether the horizontal distance condition (the absolute value of the y-coordinate of the object's relative position P(n) is less than or equal to two) is true, based on the object's information. If the CPU determines that the horizontal distance condition is true, it makes a "Yes" determination in step 804 and proceeds to step 806 below.

[0163] In step 806, for the object for which the CPU determines in step 804 that the horizontal distance condition is true, the CPU determines whether the horizontal velocity condition (SPDoy(n) ≤ 5 km / h) is true or not, based on the object's information. If the CPU determines that the horizontal velocity condition is true, the CPU makes a "Yes" determination in step 806 and performs the process of step 808 below.

[0164] Step 808: The CPU sets the value of the tracking marker for the object (approximately a parallel object) for which the CPU determined in step 806 that the horizontal velocity condition is met, to 1 and stores the set value in the RAM of the driving assistance ECU 10 associated with the object. The CPU then proceeds to step 812 as described below.

[0165] If the CPU determines in step 801 that the front presence condition is not true, if the CPU determines in step 802 that the forward and backward distance condition is not true, if the CPU determines in step 804 that the horizontal distance condition is not true, or if the CPU determines in step 806 that the horizontal velocity condition is not true, the CPU determines that the object is not the tracked object, makes a determination of "No" in any of step 801, step 802, step 804 and step 806, and performs a process of step 810 below.

[0166] Step 810: The CPU sets the tracking marker value for the object to 0 and stores this value in the RAM of the driver assistance ECU 10 associated with the object. The tracking marker is provided for each object (each object selected in step 801). The CPU then proceeds to step 812 below.

[0167] In step 812, the CPU determines whether the processes from step 801, described above, are valid for all objects with the object information specified in step 608. Fig. 6. whether the processes described above have been acquired, executed, or not. If the CPU determines that the processes described above have not yet been executed for all objects, the CPU makes a determination of "No" in step 812, returns to step 801, and repeats the processes of step 801 for the remaining objects. If the CPU determines that the processes described above have been executed for all objects, the CPU makes a determination of "Yes" in step 812 and proceeds to step 814 below.

[0168] In step 814, the CPU determines whether an object whose tracking marker value is equal to 1 is present among the objects or not (that is, whether the tracking object is present within the front area or not).

[0169] If the object whose tracking marker value is 1 exists, the CPU makes a determination of "Yes" in step 814 (that is, determines that there is no front space) and carries out the process of the following step 816.

[0170] Step 816: The CPU sets the value of the front area marker to 0 and stores the set value in the RAM of the driver assistance ECU 10. The CPU then proceeds to step 614 in Fig. 6 (described below) via step 820.

[0171] If the object whose tracking marker value is 1 does not exist, the CPU makes a determination of "No" in step 814 (that is, determines that the front space exists) and performs a process of the following step 818.

[0172] Step 818: The CPU sets the value of the front parking sensor to 1 and stores the set value in the RAM of the driver assistance ECU 10. The CPU then proceeds to step 614 in Fig. 6 via step 820.

[0173] In step 614, the CPU selects any object from among those with the object information obtained in step 608 and determines whether the attention arousal marker value for the selected object is 0. If the attention arousal marker value is 0, the CPU makes a "Yes" determination in step 614 (that is, determines that the object is not the target object), regardless of the front space marker value, and executes process 616 below. The CPU executes processes 614 through 622 for each selected object (see step 624 described below).

[0174] Step 616: The CPU does not generate the request signal for the object selected in step 614 (hereinafter referred to as a "selected object"). Therefore, the selected object is not indicated to the display device 21. The CPU then proceeds to step 624, described below.

[0175] If the value of the attention arousal marker for the selected object is equal to 1, the CPU makes a determination of "No" in step 614 and proceeds to the following step 618.

[0176] In step 618, the CPU determines whether the value of the frontal area marker is equal to 0 or not. If the CPU determines that the value of the frontal area marker is equal to 0 (that is, if the CPU determines that the value of the attention marker for the selected object is equal to 1 and that the value of the frontal area marker is equal to 0), the CPU makes a "Yes" determination in step 618 (that is, determines that, since there is no frontal area, even though the selected object is present as the target object, it is very unlikely that the target object will cross the left-side expected path and / or the right-side expected path of reference vehicle 100), and proceeds to step 620 below.

[0177] Step 620: The CPU prevents the generation of the request signal for the selected object. This prevents the display device 21 from drawing attention to the selected object. The CPU then proceeds to step 624, described below.

[0178] If the CPU determines that the value of the front space marker is equal to 1 (that is, if the CPU determines that the value of the attention arousal marker for the selected object is equal to 1 and that the value of the front space marker is equal to 1), the CPU makes a determination of "No" in step 618 (that is, determines that, since the selected object exists as the target object and the front space exists, the target object crosses the front space and consequently it is likely to cross the left expected path and / or the right expected path of reference vehicle 100) and proceeds to step 622 below.

[0179] Step 622: The CPU generates the request signal for the selected object and transmits it to the display ECU 20. The display unit 21 then draws attention to the selected object. The CPU then proceeds to step 624 below.

[0180] In step 624, the CPU determines whether the processes from step 614, described above, have been executed for all objects with the object information obtained in step 608. If the CPU determines that the processes described above have not yet been executed for all objects, the CPU makes a "No" determination in step 624, returns to step 614, and repeats the processes of step 614 for the remaining objects. For example, if any process from steps 616 and 620 for object B, which is different from object A, is being executed at the time of attention being aroused on object A by the process of step 622, the state of attention being aroused on object A continues.For example, if the process of step 622 is performed for object B, which is different from object A, at the time attention is drawn to object A by the process of step 622, attention is drawn for both object A and object B. That is, a determination of whether or not to draw attention is made for each object. If the CPU determines that the processes described above have been executed for all objects, the CPU makes a "Yes" determination in step 624 and performs the process of step 626 below.

[0181] Step 626: The CPU initializes the value of the attention marker and the tracking marker for each object (setting it to 0). The CPU also initializes the value of the front space marker (setting it to 0). The marker values ​​are initialized by the CPU when the machine switch changes from the OFF state to the ON state. The CPU then proceeds to step 628 and temporarily terminates the current routine.

[0182] The effects of the device embodied herein are described. The device embodied herein determines whether or not a frontal area exists. If the device embodied herein determines that there is no frontal area, it prohibits attention attraction, even if the device embodied herein determines that the target object is present. If there is no frontal area, the target object cannot pass in front of the reference vehicle 100. Thus, it is highly unlikely that the target object will cross the left-hand expected path and / or the right-hand expected path of the reference vehicle 100 within the threshold time period.Accordingly, even if the device embodied here determines that the target object is present, the device embodied here may prohibit attention arousal if it is actually very unlikely that the target object will cross the left-hand expected path and / or the right-hand expected path of the reference vehicle 100 within the threshold time period, due to the absence of the frontal area. Thus, the device embodied here may significantly reduce the possibility of attention arousal that need not be performed and may arouse the attention of the driver of the reference vehicle more appropriately.

[0183] In particular, the device embodied here determines whether the approximately parallel object (an object whose horizontal velocity SPDoy(n) is less than or equal to the horizontal velocity threshold) is present within the frontal area. If the device embodied here determines that such an object is present, it determines that there is no frontal area. The length of the frontal area in the x-axis direction (the direction of travel TDv of the reference vehicle 100) is equal to the forward and reverse distance threshold (6 m in the present example) and is set such that it is less than or equal to the length of any expected path of the reference vehicle 100 (7 m in the present example). Thus, the frontal area is present on the expected path of the target object.Accordingly, if the approximately parallel object is present within the frontal area, it obstructs the movement of the target object. Consequently, it is highly unlikely that the target object will cross the left-hand expected path and / or the right-hand expected path of reference vehicle 100 within the threshold time period. The configuration described above can determine that there is no frontal area if it is highly unlikely that the target object will cross the left-hand expected path and / or the right-hand expected path of reference vehicle 100 within the threshold time period. Thus, the configuration can appropriately determine whether or not the frontal area exists.

[0184] The center of the front section in the y-axis direction (the horizontal direction of reference vehicle 100) is positioned on the x-axis (that is, on a line running through the center of the front end section of reference vehicle 100 and extending in the direction of travel TDv of reference vehicle 100). The length of the front section in both the positive and negative directions of the y-axis is equal to the horizontal distance threshold value (2 m in this example). This means the front section has the same horizontal length with respect to the x-axis. Thus, by setting the horizontal distance threshold value to a suitable value, the front section can be positioned as an area in front of reference vehicle 100.Accordingly, an object located at a position horizontally separated from the front of the reference vehicle 100 can be excluded from the determination of the front space (it is not set as a target for extraction), and an object located in front of the front of the reference vehicle 100 (i.e., the tracked object) can be appropriately extracted. Thus, a determination of whether or not the front space exists can be carried out more appropriately.

[0185] While the driving assistance device according to the exemplary embodiment of the present invention has been described above, the present invention is not limited to this. Various modifications can be made to the extent that they do not deviate from the core of the invention.

[0186] For example, the order of determinations as to whether the forward and backward spacing condition, the horizontal spacing condition and the horizontal velocity condition are met or not is not limited to the configuration described above and is not fixed.

[0187] A same-direction condition, as described below, can be added to the front presence condition, the forward and reverse spacing condition, the horizontal spacing condition, and the horizontal velocity condition, as described above. That is, the same-direction condition is a condition that "an angle θip(n) between the direction of travel TDv(n) of the reference vehicle 100 and the direction of travel TDo(n) of the object is less than or equal to a predetermined angular threshold value (for example, 20°)." If the same-direction condition is true for an object, the driving assistance ECU 10 determines that the direction of travel TDo(n) of the object is approximately the same as the direction of travel TDv(n) of the reference vehicle 100.By adding the condition of the same direction to each of the conditions described above, it is possible to determine in the frontal area condition whether an object is present within the frontal area and has a direction of travel TDo(n) that is approximately the same as that of the reference vehicle 100. This allows for a more precise determination of whether the object is one that the reference vehicle 100 is following. The angle θip(n) can be calculated using the inner product of a unit vector in the direction of travel TDv(n) of the reference vehicle 100 and a unit vector in the direction of travel TDo(n) of the object.

[0188] The driver assistance device can include a warning ECU and a buzzer instead of the display ECU and display unit 21. Specifically, the warning ECU is connected to the driver assistance ECU 10 via the communication and sensor system CAN 90 in such a way that data can be exchanged. The buzzer is connected to the warning ECU. When the warning ECU receives the attention arousal request signal from the driver assistance ECU 10, the warning ECU transmits an instruction signal to the buzzer. When the buzzer receives the instruction signal from the warning ECU, the buzzer sounds an alarm to attract the driver's attention. The configuration described above can achieve the same effects as the device shown.

[0189] The device embodied here performs target object identification and frontal area determination based on object information obtained from the signals output by the three radar sensors 15, which are arranged accordingly at the left, center, and right ends of the front section of the reference vehicle 100. That is, target object identification and frontal area determination are performed based on the same object information. However, the object information used when target object identification and when frontal area determination are performed need not be the same.This means that target object determination can be performed based on object information obtained from the signals output by two radar sensors 15, located at the left and right ends of the front section of the reference vehicle 100. Frontal area determination can be performed based on object information obtained from the signal output by a radar sensor 15 located in the center of the front section of the reference vehicle 100. An object that could be the target object is relatively likely to be present on the left and right sides in front of the reference vehicle 100. The approximately parallel object that is present within the frontal area and serves as a reference for determining whether or not the frontal area exists is relatively likely to be present in front of the reference vehicle 100.This means that the configuration described above can also obtain the object information suitable for any purpose. The positions and number of radar sensors 15 that are arranged are not limited to this.

[0190] The driving assistance device can be configured to estimate one, three, or more expected paths, instead of estimating two: the left-side expected path and the right-side expected path. The expected path is not limited to paths that the left end OL and the right end OR of the reference vehicle 100 are expected to travel (i.e., the left-side expected path and the right-side expected path). For example, the expected path can be a path that the position O of the reference vehicle 100 is expected to travel. Alternatively, the left-side expected path can be a path that a point shifted to the left of the left end OL of the reference vehicle 100 by a first predetermined distance is expected to travel.The right-side expected path can be a path along which a point is expected to travel, shifted to the right by a second predetermined distance from the right end OR of the reference vehicle 100.

[0191] The driving assistance device can obtain object information using a camera or a roadside device instead of or in addition to the radar sensors 15.

[0192] The driving assistance device can be installed not only in a vehicle that drives on a road with left-hand traffic, but also in a vehicle that drives on a road with right-hand traffic.

[0193] The driving assistance device can use a value estimated from a horizontal acceleration and the vehicle speed SPDv as the yaw rate Y, or a value estimated from a steering angle and the vehicle speed SPDv as the yaw rate Y, instead of using the value detected by the yaw rate sensor 13 as the yaw rate Y.

[0194] A driver assistance device comprises a plurality of sensor devices attached to a reference vehicle (100), an attention-attracting device configured to attract the attention of a driver of the reference vehicle (100), and at least one electronic control unit (10).The at least one electronic control unit (10) obtains reference vehicle information, obtains object information, estimates an expected path that the reference vehicle (100) will travel, determines whether a target object is present or not, determines whether there is a front space in front of the reference vehicle (100) or not, based on the object information, generates a request signal to attract the attention of the driver of the reference vehicle (100), prohibits the generation of the request signal if the electronic control unit (10) determines that the target object is present and there is no front space, and controls the attention arousal device to attract the driver's attention.

Claims

[1] Driving support device, with: a plurality of sensor devices mounted on a reference vehicle (100); an attention-attracting device configured to attract the attention of a driver of the reference vehicle (100); and at least one electronic control unit (10) configured to based on detection outputs of the sensor devices, to obtain reference vehicle information including parameters relating to a vehicle speed (SPDv) of the reference vehicle (100) and a yaw rate (Y) of the reference vehicle (100), based on the detection outputs of the sensor devices, to obtain object information including a relative position of an object present around the reference vehicle (100) with respect to the reference vehicle (100), a direction of travel (TDo) of the object and a speed (SPDo) of the object, based on the reference vehicle information, to estimate an expected path that the reference vehicle (100) is expected to traverse, to determine, based on the object information, whether a target object, which is an object likely to cross the expected path within a threshold time period, is present or not, to determine based on at least the object information whether or not there is a front space, which is a space that allows the target object to pass in front of the reference vehicle (100), in front of the reference vehicle (100), to generate a request signal to attract the attention of the driver of the reference vehicle (100) when the electronic control unit (10) determines that the target object is present and there is the front space, prohibit generation of the request signal when the electronic control unit (10) determines that the target object is present and there is no front space, and to control the attention attracting device to attract the driver's attention in response to generation of the request signal, wherein: the electronic control unit (10) is configured to extract an object present around the reference vehicle (100); the electronic control unit (10) determines whether all of a predetermined forward and backward distance condition, a predetermined horizontal distance condition, and a predetermined horizontal speed condition are met or not, wherein the forward and backward distance condition is a condition that a forward and backward distance (d2), which is a distance from the reference vehicle (100) to the extracted object in a traveling direction (TDv) of the reference vehicle (100), is less than or equal to a predetermined forward and backward distance threshold value, the horizontal distance condition is a condition that a horizontal distance (d3) is less than or equal to a predetermined horizontal distance threshold value, wherein the horizontal distance (d3) is a distance from the reference vehicle (100) to the extracted object in an orthogonal direction, which is a direction orthogonal with respect to the traveling direction (TDv) of the reference vehicle (100),and the horizontal speed condition is a condition that a horizontal speed (SPDoy), which is a speed of the extracted object in the orthogonal direction, is less than or equal to a predetermined horizontal speed threshold; and , the electronic control unit (10) is configured to determine that there is no front space when the electronic control unit (10) determines that the extracted object satisfies all of the conditions. [2] A driving assistance device according to claim 1, wherein: the electronic control unit (10) is configured to determine whether the reference vehicle (100) is traveling straight or not; when the electronic control unit (10) determines that the reference vehicle (100) is traveling straight, the electronic control unit (10) estimates, as the expected path, a path extending in a linear form in the traveling direction (TDv) of the reference vehicle (100) from the reference vehicle (100) and having a predetermined length; and the electronic control unit (10) is configured to set the forward and backward distance threshold value such that it is less than or equal to the predetermined length of the expected path of the reference vehicle (100).

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