Driving Support Devices

Abstract

To control at least unnecessary activation of secondary warning control and reduce the possibility of driver annoyance.SOLUTION: A driving support device includes: an object information acquisition unit 11 and 12 for acquiring object information concerning objects detected in the vicinity of a vehicle; a direction indicator switch 13; warning devices 21 and 22; and a control unit 10 that executes primary warning control and secondary warning control with a higher alert level than the primary warning control. When detecting that the direction indicator switch 13 is on during execution of the primary warning control, the control unit 10 determines that the condition for executing the secondary warning control is met, and determines whether or not the specified condition, which is met when the rear end of the object to be subject to the primary warning passes a second reference line and no other object to be subject to the primary warning exists is satisfied based on the object information. When determining that the specified condition is met, the control unit 10 stops or inhibits the execution of the secondary warning control.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to a driving assistance device. [Background technology]

[0002] Patent Document 1 describes a driving support device that issues an alarm about a moving object (typically another vehicle) traveling on the rear side of the vehicle to alert the driver of the vehicle. This driving support device is configured to execute a control to turn on an alarm lamp as a primary alarm control when a moving object is detected in an alarm area set on the rear side of the vehicle. In addition, when a turn signal switch (strictly speaking, a turn signal switch corresponding to the side on which the moving object exists with respect to the vehicle) is on during execution of the primary alarm control, the device is configured to execute a control to flash the alarm lamp and sound a buzzer (i.e., a control with a higher level of alert) as a secondary alarm control. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2011-141746 A Summary of the Invention

[0004] In order to ensure safety when changing lanes of the vehicle, the driving assistance device can be configured to continue the primary warning control even after the moving object has left the warning area until a predetermined condition is met. The predetermined condition is, for example, a condition that a predetermined delay time has elapsed since the rear end of the moving object passed a reference line extending in the vehicle width direction set in front of the warning area. According to this configuration, it is considered that the primary warning control continues immediately after the vehicle is overtaken by the moving object because the delay time has not yet elapsed. At this time, if the vehicle operates the turn signal lever for the purpose of changing lanes (strictly speaking, changing lanes to the lane in which the moving object is traveling) and the turn signal switch is turned on, the secondary warning control is executed (in other words, the attention alert level is raised) even though the driver can definitely see the moving object. That is, the secondary warning control is unnecessarily activated, and the driver may feel annoyed.

[0005] The present invention has been made to address the above-mentioned problems. That is, one of the objects of the present invention is to provide a driving assistance device that can at least suppress unnecessary operation of the secondary warning control and reduce the possibility that the driver will feel annoyed.

[0006] The driving assistance device according to the present invention (hereinafter referred to as the "device of the present invention") comprises: a target information acquisition device (11, 12) capable of detecting targets present around a host vehicle (V) and acquiring information relating to the detected targets as target information; a turn signal switch (13) capable of detecting an operation state of an operating device (WL) operated by a driver of the vehicle (V) to activate a turn signal; an alarm device (21, 22) capable of issuing an alarm; a control unit (10) capable of executing a primary warning control, which is a control for calling the driver's attention by controlling the warning device (21) to issue a predetermined primary warning, and a secondary warning control, which is a control for raising the level of the driver's attention compared to the primary warning control, by controlling the warning devices (21, 22) to issue a predetermined secondary warning having a higher level of warning than the primary warning; Equipped with The control unit (10) Based on the target information, This is an area that is not visible in the door mirror. When a moving target (Vt) is detected in the blind spot area (R1) or when a target (Vt) approaching the vehicle (V) from the rear side is detected in the blind spot area (R1), the system determines that a condition for starting the primary warning control is satisfied and starts the primary warning control; Based on the target information, when a rear end (Pre) of a primary warning target object (Vt), which is an object that is the subject of the primary warning control, passes a first reference line (L1), which is a virtual line that is set in advance at a predetermined position of the host vehicle (V) based on a statistical distribution of the eye positions of the vehicle driver, and which extends in a vehicle width direction at a position of the front end of the blind spot area (R1) or a position forward of the front end, and a predetermined delay time (Δt) has elapsed since the rear end (Pre) of the primary warning target object (Vt), which is an object that is the subject of the primary warning control, determines that a termination condition for the primary warning control is established and terminates the primary warning control; During the execution of the primary warning control, if it is detected by the direction indicator switch (13) that the operation device (WL) is operated in a direction corresponding to the side of the host vehicle (V) on which a primary warning object (Vt) is present (step 720: Yes), it is determined that the execution condition for the secondary warning control is established. It is configured as follows: The control unit (10) further comprises: When it is determined that the execution condition is satisfied, it is determined whether or not a specific condition is satisfied based on the target information, which is satisfied when the rear end (Pre) of the primary alarm object target (Vt) passes through a second reference line (L2), which is a virtual line that is set in advance at a predetermined position relative to the host vehicle (V), the second reference line (L2) extending in the vehicle width direction at a position forward of the first reference line (L1), and there is no other primary alarm object target (step 730, step 750); When it is determined that the specific condition is satisfied (step 730: Yes and step 750: No), the execution of the secondary warning control is stopped or suppressed regardless of the determination result that the execution condition is satisfied (step 760). When it is determined that the specific condition is not satisfied (step 730: No or step 750: Yes), the secondary warning control is executed according to the determination result (step 740). It was configured as follows: Driving assistance device.

[0007] When the execution condition of the secondary warning control is satisfied, the device of the present invention judges whether or not the specific condition is satisfied. The specific condition is a condition that is satisfied when the rear end of the primary warning object passes through the second reference line and there is no other primary warning object. When the device of the present invention judges that the specific condition is satisfied, it stops or suppresses the execution of the secondary warning control regardless of the judgment result that the execution condition of the secondary warning control is satisfied, and when it judges that the specific condition is not satisfied, it executes the secondary warning control according to the judgment result. The second reference line is located at a position forward of the first reference line (a virtual line that is set in advance based on the statistical distribution of the eye position of the driver of the vehicle). Therefore, when the rear end of the primary warning object passes through the second reference line, the driver of the vehicle can reliably see the primary warning object. Therefore, the specific condition can also be said to be a condition that is satisfied when the possibility of the presence of an object (obstruction object) that obstructs the safe lane change of the vehicle is extremely low. In this way, the device of the present invention is configured to determine whether or not a specific condition is satisfied, and to stop or suppress the execution of the secondary warning control when the possibility of the presence of an obstructing object is extremely low, rather than uniformly (automatically) executing the secondary warning control when the execution condition is satisfied. Therefore, according to the device of the present invention, it is possible to at least suppress unnecessary operation of the secondary warning control, and reduce the possibility that the driver will feel annoyed.

[0008] In the above description, in order to facilitate understanding of the invention, the symbols used in the embodiments are added in parentheses to the constituent elements of the invention corresponding to the embodiments, but each constituent element of the invention is not limited to the embodiment defined by the said symbols. [Brief description of the drawings]

[0009] [Figure 1] 1 is a schematic configuration diagram of a driving assistance device according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a diagram showing blind spot areas of a host vehicle while it is traveling. [Diagram 3] FIG. 2 is a diagram showing a sudden approach determination region of the host vehicle while traveling. [Figure 4] FIG. 13 is a diagram for explaining a termination condition of the primary warning control. [Diagram 5] FIG. 13 is a diagram for explaining unnecessary operation of the secondary warning control. [Figure 6] FIG. 13 is a diagram for explaining a specific condition. [Figure 7] 4 is a flowchart showing a routine (secondary warning control execution suppression determination process) executed by a CPU of a driving assistance ECU included in the driving assistance device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] (Embodiment) Hereinafter, a driving assistance device according to this embodiment (hereinafter also referred to as "this embodiment device") will be described with reference to the drawings. As shown in FIG. 1, this embodiment device includes a driving assistance ECU 10, and a front side radar sensor 11, a rear side radar sensor 12, a turn signal switch 13, a door mirror indicator 21, and a buzzer 22 connected thereto. The driving assistance ECU 10 includes a microcomputer as a main part. ECU is an abbreviation for Electronic Control Unit. The microcomputer includes a CPU, storage devices such as ROM and RAM, and an interface (I / F), and the CPU realizes various functions by executing instructions (programs) stored in the ROM. Hereinafter, a vehicle equipped with this embodiment device will be referred to as "own vehicle".

[0011] The driving assistance ECU 10 is configured to acquire signals output by the sensors 11 and 12 and a signal generated by the switch 13 every time a predetermined calculation time elapses, and control the door mirror indicators 21 and the buzzer 22 based on the acquired signals. Hereinafter, the driving assistance ECU 10 is also simply referred to as "ECU 10."

[0012] The front-side radar sensor 11 (target information acquisition device) has a function of acquiring information about three-dimensional objects present in front of and to the sides of the vehicle (including the sides). The three-dimensional objects include moving objects such as other vehicles, bicycles, and pedestrians, and stationary objects such as guard rails, side walls, and roadside trees.

[0013] The front side radar sensor 11 includes a left front side radar sensor 11L and a right front side radar sensor 11R. The left front side radar sensor 11L and the right front side radar sensor 11R are provided at the left and right corners of the front bumper of the vehicle, respectively. The left front side radar sensor 11L irradiates millimeter wave band radio waves to the left front side (including the left side) of the vehicle, and the right front side radar sensor 11R irradiates millimeter wave band radio waves to the right front side (including the right side) of the vehicle.

[0014] When a three-dimensional object is present within the irradiation range of the radio wave, the front-side radar sensor 11 receives a reflected wave from the three-dimensional object, and calculates the presence or absence of the three-dimensional object and the relative relationship between the vehicle and the three-dimensional object (the distance from the vehicle to the three-dimensional object, the orientation of the three-dimensional object relative to the vehicle, and the relative speed of the three-dimensional object relative to the vehicle, etc.) based on the irradiation timing and reception timing of the radio wave, etc. In other words, the front-side radar sensor 11 detects a three-dimensional object present in front of the vehicle.

[0015] The rear-side radar sensor 12 (target information acquisition device) has a function of acquiring information about three-dimensional objects present on the rear side (including the sides) of the vehicle. The rear-side radar sensor 12 has the same basic configuration as the front-side radar sensor 11, except for the irradiation range of radio waves (detection range of three-dimensional objects). Therefore, the following mainly describes the differences from the front-side radar sensor 11.

[0016] The rear side radar sensor 12 includes a left rear side radar sensor 12L and a right rear side radar sensor 12R. The left rear side radar sensor 12L and the right rear side radar sensor 12R are provided at the left and right corners of the rear bumper of the vehicle, respectively. The left rear side radar sensor 12L irradiates radio waves to the left rear side (including the left side) of the vehicle, and the right rear side radar sensor 12R irradiates radio waves to the right rear side (including the right side) of the vehicle.

[0017] The rear-side radar sensor 12 calculates the presence or absence of a three-dimensional object and the relative relationship between the vehicle and the three-dimensional object based on the timing of emitting and receiving radio waves, etc. In other words, the rear-side radar sensor 12 detects a three-dimensional object that exists on the rear side of the vehicle.

[0018] Hereinafter, a three-dimensional object detected by the front-side radar sensor 11 or the rear-side radar sensor 12 will also be referred to as a "target." The front-side radar sensor 11 and the rear-side radar sensor 12 output the above-mentioned information on the target to the ECU 10 as "front-side target information" and "rear-side target information," respectively.

[0019] The turn signal switch 13 (directional indicator switch) is provided on a turn signal lever WL (not shown). The turn signal lever WL is an operating device operated by the driver to make the turn signal (directional indicator) blink, and is provided on the steering column. The turn signal lever WL is operated when the driver changes lanes or turns left or right by driving the vehicle himself.

[0020] Specifically, the turn signal lever WL is configured to be movable to a right position PR or a left position PL, which are positions rotated counterclockwise or clockwise by a predetermined angle from a neutral position around a support shaft. The turn signal switch 13 includes a right turn signal switch 13R and a left turn signal switch 13L. The right turn signal switch 13R is turned on (generates an on signal) when the turn signal lever WL is in the right position PR, and is turned off (generates an off signal) otherwise. The left turn signal switch 13L is turned on (generates an on signal) when the turn signal lever WL is in the left position PL, and is turned off (generates an off signal) otherwise. The ECU 10 acquires the signal generated by the turn signal switch 13, and detects the operation state of the turn signal lever WL based on the signal.

[0021] The door mirror indicator 21 (alarm device) includes a left door mirror indicator 21L and a right door mirror indicator 21R. The left door mirror indicator 21L is provided at a predetermined position on the left door mirror (left door mirror) DML (see FIG. 2) of the vehicle. When the left door mirror indicator 21L is activated, a predetermined mark (typically, a mark indicating that another vehicle is present on the left rear side of the vehicle) lights up or flashes. The right door mirror indicator 21R is provided at a predetermined position on the right door mirror (right door mirror) DMR (see FIG. 2) of the vehicle. When the right door mirror indicator 21R is activated, a predetermined mark (typically, a mark indicating that another vehicle is present on the right rear side of the vehicle) lights up or flashes. The left and right door mirror indicators 21L and 21R are configured to operate independently of each other.

[0022] The buzzer 22 (alarm device) is built into a meter panel (not shown) and emits a sound by ringing.

[0023] (Details of operation) The ECU 10 has a blind spot monitor (BSM) function. The BSM function is a function that alerts the driver by issuing an alarm when a target is detected in the blind spot area (i.e., an area not reflected in the door mirror DM) of the vehicle while driving, or when a target is detected in the blind spot area approaching rapidly from the rear side, thereby improving safety when changing lanes. As the BSM function, the ECU 10 is configured to be able to execute primary alarm control and secondary alarm control.

[0024] The primary warning control is a control in which the door mirror indicator 21 (strictly speaking, the indicator in which the target object to be warned is detected) is turned on as a primary warning, thereby alerting the driver. The secondary warning control is a control in which the state of the door mirror indicator 21 is switched from on to flashing as a secondary warning, and the buzzer 22 is sounded, thereby alerting the driver more strongly. In other words, the secondary warning is a higher level of warning than the primary warning, and the secondary warning control is a control in which the level of alerting the driver is raised compared to the primary warning control. The primary warning control and the secondary warning control will be specifically described below. In addition, in order to make the drawings easier to see, the dimensions of the vehicle and the dimensions of various areas in the drawings may be illustrated as being different from each other.

[0025] First, the conditions for starting the primary warning control will be described. When at least one of the following conditions 1 and 2 is satisfied, the ECU 10 determines that the start conditions are satisfied and starts the primary warning control for the target that satisfies the conditions. (Condition 1) A target (moving object) is detected in a blind spot area R1 (described later). (Condition 2) The TTC (described later) of a target (moving object) detected in the sudden approach determination region R2 (described later) is equal to or less than a predetermined TTC threshold value.

[0026] Condition 1 will be described with reference to FIG. 2. FIG. 2 is a diagram showing a blind spot area R1 of a vehicle V while traveling. In FIG. 2, the x-axis is set so that the traveling direction of the vehicle V is the +x-axis direction, and the y-axis is set so that the vehicle width right direction is the +y-axis direction (this is the same for other figures). As shown in FIG. 2, the blind spot area R1 includes a blind spot area R1L and a blind spot area R1R. The blind spot area R1R is a rectangular area located on the right rear side (including the right side) of the vehicle V and has a predetermined size. Specifically, the blind spot area R1R is surrounded by a long side extending in the x-axis direction and a short side extending in the y-axis direction, and the length of the long side is Lx1 and the length of the short side is Ly1 (Lx1>Ly1). The blind spot area R1R is separated by a predetermined distance in the +y-axis direction from the right side surface of the vehicle body of the vehicle V. In addition, the front part of the blind spot area R1R overlaps in the x-axis direction with the center and rear parts of the host vehicle V. However, the length of the portion of the long side of the blind spot area R1R that overlaps with the host vehicle V is shorter than the length of the portion that does not overlap.

[0027] The blind spot area R1L is disposed symmetrically with the blind spot area R1R with respect to the front-rear axis (the axis passing through the center of the vehicle width of the vehicle V and parallel to the x-axis direction) of the vehicle V. For this reason, a detailed description of the blind spot area R1L will be omitted.

[0028] The blind area R1R is included in the irradiation range of the radio waves of the right rear side radar sensor 12R, and the blind area R1L is included in the irradiation range of the radio waves of the left rear side radar sensor 12L. The ECU 10 determines whether the target is a moving object based on the rear side target information, and if it is determined that the target is a moving object, determines whether at least a part of the target is located within the blind area R1. If it is determined that at least a part of the target is located within the blind area R1, the ECU 10 determines that the condition 1 is satisfied for the target.

[0029] Next, condition 2 will be described with reference to FIG. 3. FIG. 3 is a diagram showing a sudden approach judgment region R2 of the host vehicle V while traveling. Hereinafter, the "sudden approach judgment region" may be simply referred to as "region". As shown in FIG. 3, region R2 includes region R2L and region R2R. Region R2R is a rectangular region located on the right rear side of the host vehicle V, and has a predetermined size. Specifically, region R2R is surrounded by a long side extending in the x-axis direction and a short side extending in the y-axis direction, and the length of the long side is Lx2 and the length of the short side is Ly2 (Lx2>Ly2). The front end of region R2R is located slightly forward (in the +x-axis direction) of the rear end of the host vehicle V.

[0030] When the sudden approach determination region R2R is compared with the blind spot region R1R (see FIG. 2), the following relationship holds: Ly2=Ly1 Lx2>Lx1 However, the length Ly2 and the length Ly1 do not necessarily have to be the same value. Furthermore, the shape of the region R2R is not limited to the above, and may be, for example, a trapezoid.

[0031] The region R2L is disposed symmetrically with the region R2R with respect to the longitudinal axis of the host vehicle V. For this reason, a detailed description of the region R2L will be omitted.

[0032] The region R2R is included in the irradiation range of the radio wave of the right rear-side radar sensor 12R, and the region R2L is included in the irradiation range of the radio wave of the left rear-side radar sensor 12L. The ECU 10 judges whether the target is a moving object based on the rear-side target information, and when it is judged to be a moving object, judges whether the target is located in the region R2. When it is judged that the target is located in the region R2, the ECU 10 calculates the TTC of the target and judges whether TTC≦TTC threshold is satisfied. Here, TTC is an abbreviation of Time To Collision, and means a collision prediction time (a time predicted to be required until the target collides with the host vehicle V). In this embodiment, the value obtained by dividing the "relative distance of the target in the x-axis direction with respect to the host vehicle V" by the "relative speed component of the target in the x-axis direction with respect to the host vehicle V" is defined as the TTC. The TTC threshold is a threshold that determines whether the degree of approach of the target to the host vehicle V is rapid, and can be calculated in advance by an experiment or a simulation. In this embodiment, it is assumed that the target is moving straight in the +x-axis direction. In this case, the "relative speed component of the target in the x-axis direction with respect to the host vehicle V" is the same as the "relative speed of the target with respect to the host vehicle V." In addition, the method of calculating the TTC is not limited to the above.

[0033] When it is determined that TTC≦TTC threshold is satisfied for the target, the ECU 10 determines that condition 2 is satisfied for the target. Note that, as is clear from Fig. 2 and Fig. 3, the region R2R or R2L partially overlaps with the blind spot region R1R or R1L, respectively, in the x-axis direction. For this reason, there may be cases where a certain target satisfies both condition 1 and condition 2.

[0034] Next, the conditions for ending the primary warning control will be described. When any one of the following conditions 3 to 6 is satisfied, the ECU 10 determines that the condition is satisfied and ends the primary warning control for the target that satisfies the condition. (Condition 3) A time Tf has elapsed after the rear end of the target has passed a first reference line L1 (described later). (Condition 4) Time Tre has elapsed since the front end of the target moved away from the rear end of the blind spot region R1. (Condition 5) A time Tr has elapsed since the left edge of the target receded from the right edge of the blind spot region R1. (Condition 6) Time Tl has elapsed since the center of the target moved away from the left edge of the blind spot region R1.

[0035] Conditions 3 to 6 will be described with reference to FIG. 4. FIG. 4 is a diagram showing a host vehicle V and another vehicle Vt located in the blind spot area R1R. In the example of FIG. 4, since condition 1 is satisfied, the primary warning control is started. The method of determining whether conditions 3 to 6 are satisfied is the same for blind spot areas R1L and R1R. For this reason, the following description will be given taking blind spot area R1R as an example, and a detailed description of blind spot area R1L will be omitted.

[0036] First, the condition 3 will be described. As shown in FIG. 4, during the execution of the primary warning control, the ECU 10 sets a first reference line L1 on the host vehicle V. The first reference line L1 is a virtual line that passes through a position PelL on the left side of the vehicle body of the host vehicle V and a position PelR on the right side of the vehicle body, and extends in the vehicle width direction. The positions PelL and PelR are located behind the left and right door mirrors DML and DMR, respectively. Here, it is known that the statistical distribution of the eye positions of drivers with different heights, physiques, sex, etc. is elliptical (so-called iris). The position of the first reference line L1 is determined based on this iris. For this reason, the eye position of the driver of the host vehicle V can be considered to be located on or near the first reference line L1. The iris is a compound word of "eye" and "ellipse". In this embodiment, the first reference line L1 is located forward of the front end of the blind spot area R1. However, depending on how the blind spot area R1 is set, the first reference line L1 may be located at the front end of the blind spot area R1.

[0037] The ECU 10 judges whether or not the rear end Pre of the other vehicle Vt has passed the first reference line L1 based on the rear side target information. If it is judged that the rear end Pre has passed the first reference line L1, it judges whether or not a predetermined time Tf has passed since the time point when the rear end Pre passed the first reference line L1. If it is judged that the time Tf has passed, the ECU 10 judges that the condition 3 is satisfied for the other vehicle Vt.

[0038] Depending on the performance of the rear-side radar sensor 12, when the other vehicle Vt is traveling at a point where its rear end Pre is located near the first reference line L1, the other vehicle Vt may not be detected properly (i.e., the other vehicle Vt may not be included in the irradiation range of the radio waves from the rear-side radar sensor 12). In this case, the ECU 10 determines whether or not Condition 3 is satisfied, assuming that the other vehicle Vt continues traveling at the latest relative speed of the other vehicle Vt included in the rear-side target information output from the rear-side radar sensor 12 every time a predetermined calculation time elapses.

[0039] Next, conditions 4 to 6 will be described. The ECU 10 judges, based on the rear side target information, whether the front end Pf of the other vehicle Vt has retreated from the side e1, which is the rear end of the blind spot area R1R, and whether a predetermined time Tre has passed since the retreated point. If it is judged that the front end Pf has retreated from the side e1 and the time Tre has passed since the retreated point, the ECU 10 judges that condition 4 is satisfied for the other vehicle Vt. Furthermore, the ECU 10 determines whether the left end PlaL of the other vehicle Vt has retreated from the side e2, which is the right end of the blind spot area R1R, and whether a predetermined time Tr has elapsed since the retreat based on the rear side target information. If it is determined that the left end PlaL has retreated from the side e2 and the time Tr has elapsed since the retreat, the ECU 10 determines that the condition 5 is satisfied for the other vehicle Vt. Furthermore, the ECU 10 determines whether the center of the other vehicle Vt has moved away from the side e3, which is the left end of the blind spot area R1R, and whether a predetermined time Tl has elapsed since the center of the other vehicle Vt moved away from the side e3, based on the rear side target information. If it is determined that the center of the other vehicle Vt has moved away from the side e3 and the time Tl has elapsed since the center of the other vehicle Vt moved away, the ECU 10 determines that the condition 6 is satisfied for the other vehicle Vt.

[0040] That is, the ECU 10 starts the primary warning control when at least one of Condition 1 or Condition 2 is satisfied for a certain target, and thereafter executes the primary warning control until any one of Conditions 3 to 6 is satisfied for the target. Hereinafter, the target subject to the primary warning control is also referred to as the "primary warning target". As is clear from the above description, the ECU 10 continues the primary warning control until a predetermined time (time Tf, time Tre, time Tr, and time Tl) has elapsed even after all (conditions 3 to 5) or a part (condition 6) of the primary warning target has retreated from the blind spot area R1. These predetermined times are times that are determined in advance to ensure safety when changing lanes, but in other words, the timing at which the primary warning control ends can be delayed by the times Tf, time Tre, time Tr, and time Tl, respectively. Therefore, hereinafter, the times Tf, time Tre, time Tr, and time Tl of Conditions 3 to 6 are also referred to as the "delay time Δt".

[0041] Next, the execution condition of the secondary warning control will be described. When the following condition 7 is satisfied during the execution of the primary warning control, the ECU 10 determines that the execution condition is satisfied. (Condition 7) The turn signal switch 13 corresponding to the side of the host vehicle on which the primary alarm target exists is turned on.

[0042] Condition 7 will now be described. During execution of the primary warning control, the ECU 10 judges whether or not either the left or right turn signal switch 13L or 13R is on based on a signal generated by the turn signal switch 13. If it is judged that either the left or right turn signal switch 13L or 13R is on, it judges whether or not the turn signal switch 13 on the side that is on corresponds to the side (i.e., the left or right side) where the primary warning object is present with respect to the vehicle. If they correspond, the ECU 10 judges that condition 7 is met.

[0043] That is, when condition 7 is satisfied while primary warning control is being executed for a certain target, ECU 10 determines that the execution condition for secondary warning control is satisfied while condition 7 is satisfied.

[0044] Here, if the ECU 10 is configured to uniformly (automatically) execute the secondary warning control when it is determined that the execution condition of the secondary warning control is satisfied, it may cause unnecessary operation of the secondary warning control, which may be annoying to the driver. Hereinafter, a specific description will be given with reference to Fig. 5. Fig. 5 is a diagram showing a scene in which another vehicle Vt overtakes the host vehicle V. In the example of Fig. 5, it is assumed that the ECU 10 is configured to uniformly execute the secondary warning control when it is determined that the execution condition of the secondary warning control is satisfied.

[0045] As shown in FIG. 5, the host vehicle V travels straight at a speed v, and the other vehicle Vt travels straight at a speed vt (>v). The other vehicle Vt travels in the right adjacent lane (the lane adjacent to the lane in which the host vehicle V travels on the right side). The rear end Pre of the other vehicle Vt passes the first reference line L1 at time t=T0, and advances a distance d from the first reference line L1 at time t=T2. The difference between time t=T2 and time t=T0 is equal to the delay time Δt of condition 3 (T2-T0=Tf). That is, the ECU 10 recognizes the other vehicle Vt as a primary warning object and continues the primary warning control until the delay time Δt has elapsed since the rear end Pre of the other vehicle Vt passed the first reference line L1. The distance d can be calculated by integrating the relative speed vt-v of the other vehicle Vt with respect to the host vehicle V over time from T1 to T2. In the example of FIG. 5, it is assumed that there is no primary alarm target other than the other vehicle Vt.

[0046] Here, since the driver of the vehicle V can already see a part of the other vehicle Vt at time t=T0, it is considered that the driver can certainly see the other vehicle Vt overtaking the vehicle V before the delay time Δt has elapsed. If the driver operates the turn signal lever WL to turn on the right turn signal switch 13R with the intention of changing lanes to the adjacent lane on the right before the delay time Δt has elapsed, the ECU 10 determines that the execution condition for the secondary warning control is satisfied due to the satisfaction of condition 7, and starts (executes) the secondary warning control. In this case, since the driver can see the other vehicle Vt and there are no other objects that are the subject of the primary warning, the secondary warning control is started (in other words, the attention alert level is raised) even though the vehicle V can safely change lanes, and the secondary warning control is unnecessarily activated, which causes the driver to feel annoyed.

[0047] Therefore, in this embodiment, when it is determined that the execution condition of the secondary warning control is satisfied, the ECU 10 does not uniformly execute the control, but judges whether or not "a specific condition that is satisfied when the possibility that a target obstructing a safe lane change of the vehicle V (hereinafter also referred to as an "obstruction target") exists is extremely low" and determines whether or not the execution of the secondary warning control is suppressed based on whether or not the specific condition is satisfied. Hereinafter, a specific description will be given with reference to FIG. 6.

[0048] FIG. 6 is a diagram showing the relative positional relationship between the host vehicle V and the other vehicle Vt at time t=T1. In the example of FIG. 6, the execution condition of the secondary warning control is met. That is, the primary warning control is being executed for the other vehicle Vt, and the right turn signal switch 13R is on. In other words, the time t=T1 is the time from when the rear end Pre of the other vehicle Vt passes the first reference line L1 until the delay time Δt has elapsed. Also, in the example of FIG. 6, it is assumed that there is no other object for which a primary warning is issued other than the other vehicle Vt.

[0049] As shown in FIG. 6, during the period when the execution condition for the secondary warning control is satisfied, the ECU 10 sets a second reference line L2 for the host vehicle V. The second reference line L2 is a virtual line that passes through the front end Pf of the host vehicle V and extends in the vehicle width direction. That is, the second reference line L2 is set at a position forward of the first reference line L1. Therefore, when the rear end Pre of the other vehicle Vt passes the second reference line L2, it is considered that the driver can reliably see the other vehicle Vt. In this way, when the driver can reliably see the other vehicle Vt overtaking the host vehicle V and there is no other primary warning target object, it is extremely unlikely that an obstruction target object exists, so it is considered that the host vehicle V can change lanes sufficiently safely even if the delay time Δt has not elapsed. For this reason, the ECU 10 is configured to determine that the specific condition is satisfied when the following conditions 8 and 9 are both satisfied. (Condition 8) The rear end of the primary alarm object passes through the second reference line L2. (Condition 9) There are no other targets for the primary alarm.

[0050] First, condition 8 will be described. Based on the front-side target information, the ECU 10 determines whether or not the rear end Pre of the primary warning target (in the example of FIG. 6, another vehicle Vt) has passed the second reference line L2. If it is determined that the rear end Pre has passed the second reference line L2, it determines that condition 8 is satisfied for the primary warning target. As described above, the ECU 10 acquires the front-side target information and the rear-side target information output from the front-side radar sensor 11 and the rear-side radar sensor 12 every time a predetermined calculation time has elapsed. The ECU 10 integrates and processes the acquired front-side target information and the rear-side target information. Therefore, even if a certain target travels at a higher speed than the host vehicle V and, as a result, the radar sensor that detects the target is switched from the rear-side radar sensor 12 to the front-side radar sensor 11, the ECU 10 can appropriately identify the target based on the transition of the relative relationship between the host vehicle V and the target. In this embodiment, the second reference line L2 is set at a position passing through the front end Pf of the vehicle V, but is not limited to this configuration. For example, the second reference line L2 may be set at a position slightly forward of the front end Pf (i.e., a position away from the vehicle V), or at a position rearward of the front end Pf (but forward of the first reference line L1).

[0051] Next, a description will be given of condition 9. When it is determined that condition 8 is satisfied, the ECU 10 determines whether or not there is another primary alarm target object based on the rear-side target information, and when it is determined that there is no other target object, it determines that condition 9 is satisfied.

[0052] When the ECU 10 determines that the specific condition is met due to the satisfaction of the conditions 8 and 9, it determines that the possibility of the presence of an obstructing object is extremely low, and suppresses the execution of the secondary warning control regardless of the determination result that the execution condition of the secondary warning control is met. Specifically, it switches the state of the door mirror indicator 21 from on to flashing, and stops the sounding of the buzzer 22. Note that the ECU 10 may be configured to stop the secondary warning control instead of suppressing the execution of the secondary warning control when it is determined that the specific condition is met.

[0053] On the other hand, if it is determined that the specific condition is not satisfied, ECU 10 determines that there is a possibility that an obstructing object is present, and executes the secondary warning control in accordance with the determination result that the execution condition for the secondary warning control is satisfied.

[0054] (Specific operation) Next, a specific operation of the ECU 10 for determining whether or not to suppress the execution of the secondary warning control will be described. The CPU of the ECU 10 is configured to repeatedly execute a routine (secondary warning control execution suppression determination process) shown in the flowchart of FIG. 7 every time a predetermined calculation time elapses while the ignition switch is on.

[0055] At a predetermined timing, the CPU proceeds from step 700 to step 710 and determines whether or not primary warning control is being executed (conditions 1 to 6). In other words, the CPU determines whether or not a primary warning target object is present. If primary warning control is not being executed (step 710: No), the CPU proceeds to step 795 and temporarily ends this routine. On the other hand, if primary warning control is being executed (step 710: Yes), the CPU proceeds to step 720.

[0056] In step 720, the CPU determines whether or not the turn signal switch 13 (strictly speaking, the turn signal switch 13 corresponding to the side of the vehicle on which the primary alarm target object is present) is on based on the signal generated by the turn signal switch 13 (condition 7). If the turn signal switch 13 is off (step 720: No), the CPU determines that the execution condition for secondary alarm control is not met, proceeds to step 795, and temporarily ends this routine. On the other hand, if the turn signal switch 13 is on (step 720: Yes), the CPU determines that the execution condition for secondary alarm control is met, and proceeds to step 730.

[0057] In step 730, the CPU determines whether or not the rear end Pre of the primary alarm object has passed the second reference line L2 based on the front-side target information (condition 8). If it has not passed (step 730: No), the CPU determines that the specific condition is not met (there is a possibility that an obstructing object exists), and proceeds to step 740 to execute secondary alarm control. That is, the attention level is increased. Thereafter, the CPU proceeds to step 795 to temporarily end this routine. On the other hand, if it has passed (step 730: Yes), the CPU proceeds to step 750.

[0058] In step 750, the CPU determines whether or not there is another target object for the primary alarm (condition 9). If there is another target object for the primary alarm (step 750: Yes), the CPU determines that the specific condition is not met (there is a possibility that an obstructing target is present), proceeds to step 740, and executes secondary alarm control. Thereafter, the CPU proceeds to step 795, and temporarily ends this routine. On the other hand, if there is no other target object for the primary alarm (step 750: No), the CPU determines that the specific condition is met (there is no obstructing target), and proceeds to step 760.

[0059] In step 760, the CPU suppresses the execution of the secondary warning control. This suppresses unnecessary operation of the secondary warning control, making it less likely that the driver will feel bothered. After that, the CPU proceeds to step 795 and temporarily ends this routine.

[0060] As described above, when the execution condition of the secondary warning control is satisfied, the present embodiment device judges whether or not the specific condition is satisfied. If it is judged that the specific condition is satisfied, the execution of the secondary warning control is suppressed regardless of the judgment result that the execution condition of the secondary warning control is satisfied, and if it is judged that the specific condition is not satisfied, the secondary warning control is executed according to the judgment result. The specific condition is a condition that is satisfied when the possibility that a target (obstruction target) that obstructs the safe lane change of the vehicle is present is extremely low. Therefore, according to the present embodiment device, unnecessary operation of the secondary warning control can be suppressed, and the possibility that the driver feels annoyed can be reduced.

[0061] Although the driving assistance device according to the embodiment has been described above, the present invention is not limited to the above embodiment, and various modifications are possible without departing from the object of the present invention.

[0062] For example, the ECU 10 may be configured to vibrate the steering wheel as the secondary warning control, in addition to flashing the door mirror indicators 21 and sounding the buzzer 22. In this case, the ECU 10 may be configured to stop vibration of the steering wheel when execution of the secondary warning control is suppressed due to the establishment of a specific condition. [Explanation of symbols]

[0063] 10: Driving assistance ECU, 11: Front side radar sensor, 12: Rear side radar sensor, 13: Turn signal switch, 21: Door mirror indicator, 22: Buzzer

Claims

[Claim 1] a target information acquisition device that detects targets present around the vehicle and acquires information about the detected targets as target information; a turn signal switch capable of detecting an operation state of an operating device operated by a driver of the vehicle in order to activate a turn signal; An alarm device capable of issuing an alarm; a control unit capable of executing a primary warning control, which is a control for calling the driver's attention by controlling the warning device to issue a predetermined primary warning, and a secondary warning control, which is a control for raising the level of calling the driver's attention compared to the primary warning control, by controlling the warning device to issue a predetermined secondary warning having a higher level of warning than the primary warning; Equipped with The control unit When a moving target is detected in a blind spot area, which is an area not reflected in the door mirror of the vehicle, based on the target information, or when a target approaching rapidly from the rear side of the vehicle is detected in the blind spot area, the system determines that a start condition for the primary warning control is satisfied and starts the primary warning control; based on the target information, when a predetermined delay time has elapsed since the rear end of a primary alarm target object, which is an object that is the subject of the primary alarm control, has passed a first reference line, which is a virtual line that is preset at a predetermined position of the host vehicle based on a statistical distribution of the eye positions of the vehicle driver, and which extends in a vehicle width direction at a position of the front end of the blind spot area or a position forward of the front end, the method determines that a termination condition for the primary alarm control is established and terminates the primary alarm control; When it is detected by the turn signal switch during execution of the primary warning control that the operating device is operated in a direction corresponding to a side on which a primary warning target object is present with respect to the host vehicle, it is determined that a condition for executing the secondary warning control is established. It is configured as follows: The control unit further comprises: When it is determined that the execution condition is satisfied, it is determined based on the target information whether or not a specific condition is satisfied that is satisfied when the rear end of the primary alarm object target passes through a second reference line, which is a virtual line that is set in advance at a predetermined position relative to the vehicle, the second reference line extending in the vehicle width direction at a position forward of the first reference line, and there is no other primary alarm object target; When it is determined that the specific condition is satisfied, the execution of the secondary warning control is stopped or suppressed regardless of the determination result that the execution condition is satisfied, When it is determined that the specific condition is not satisfied, the secondary warning control is executed in accordance with the determination result. It was configured as follows: Driving assistance device.

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