JP2014149627A - Driving support device and driving support method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a driving support device and a driving support method which can suppress an uncomfortable feeling of a driver produced by switching a calculation system in determining driving support.SOLUTION: A driving support device includes an object sensor 22 for detecting at least one object in a travelling direction of a subject vehicle. The driving support device further includes a driving support determination unit 12 for performing the steps of: calculating a first support request level by using a first calculation system and also calculating a second support request level by using a second calculation system different from the first calculation system; calculating a support determination value such that the lower the number of detected objects is, the more greatly the first support request level is weighted, and the higher the number of the detected objects is, the more greatly the second support request level is weighted; and determining driving support of the subject vehicle on the basis of the support determination value.

Description

  The present invention relates to a driving support device and a driving support method that support driving of a host vehicle.

  Conventionally, in relation to the driving support device and the driving support method, for example, Japanese Patent Application Laid-Open No. 2005-10935 corresponds to the number of other moving bodies and prevents a delay in notification of a collision due to a calculation time of a collision possibility. The driving support system is described. In this system, the possibility of collision between the host vehicle and another moving body is calculated, and if there is a possibility of collision, the passenger is notified. Here, when the number of other moving objects is large, for example, when the threshold value is exceeded, the other moving objects that are close to each other are regarded as one other moving object, and the possibility of collision is calculated by a simple method with a small amount of calculation. Is done.

JP 2005-10935 A

  However, in such a system, if the calculation method is suddenly switched according to the change in the number of other moving bodies to be detected, the driver may feel uncomfortable with the determination of driving assistance such as notification.

  Therefore, the present invention intends to provide a driving support device and a driving support method that can suppress a driver's uncomfortable feeling that occurs with respect to determination of driving support by switching arithmetic methods.

  The driving support apparatus according to the present invention calculates an first detection request level by an object detection unit that detects at least one object in the traveling direction of the host vehicle, the first calculation method, and the first calculation method. The second support request level is calculated by a different second calculation method, and the first support request level is weighted more as the number of detected objects is smaller, and the second support request level is increased as the number of detected objects is larger. A driving support determination unit that calculates a support determination value by weighting the degree greatly and determines driving support of the host vehicle based on the support determination value.

  The driving support method according to the present invention detects at least one object in the traveling direction of the host vehicle, calculates the first support request level by the first calculation method, and is different from the first calculation method. The second support request level is calculated by an arithmetic method, and the first support request level is weighted more as the number of detected objects is smaller, and the second support request level is weighted more as the number of detected objects is larger. Calculating a support determination value and determining driving support of the host vehicle based on the support determination value.

  According to the driving support device and the driving support method according to the present invention, the first support request level calculated by the first calculation method and the second calculation method are calculated according to the change in the number of detected objects. The assistance determination value is calculated in consideration of the second assistance request level, and driving assistance is determined based on the assistance determination value. Therefore, since the calculation method does not suddenly change according to the change in the number of detected objects, it is possible to suppress the driver's uncomfortable feeling that occurs with respect to the determination of driving assistance.

  ADVANTAGE OF THE INVENTION According to this invention, the driving assistance apparatus and driving assistance method which can suppress the driver | operator's uncomfortable feeling which arises with respect to determination of driving assistance by switching of an arithmetic system can be provided.

It is a block diagram which shows the driving assistance device which concerns on embodiment of this invention. It is a flowchart which shows the driving assistance method which concerns on embodiment of this invention. It is a figure which shows an example of a weighting coefficient. It is a figure which shows an example of the collision risk map used for driving assistance. It is a figure which shows the example of calculation of the collision risk by a collision risk map. It is a figure which shows the example of calculation of the collision risk by a collision risk map. It is a figure which shows the example of judgment of the collision risk by a driver | operator. It is a figure which shows an example of the condition where discomfort may arise by switching of an arithmetic method. It is a figure which shows the other example of the condition where discomfort may arise by switching of an arithmetic method.

  Hereinafter, a driving support device and a driving support method according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted.

  First, with reference to FIG. 4 to FIG. 9, a technology that is a premise of the driving support apparatus and driving support method according to the embodiment of the present invention will be described.

  The driving support device detects an object in the traveling direction of the host vehicle, calculates a collision risk between the host vehicle and the object, and determines driving support for the host vehicle based on the collision risk. For driving support, for example, a collision risk map indicating the relationship between the time until the vehicle reaches the point where the course of the vehicle intersects the course of the object (the route intersection) and the collision risk is used.

  FIG. 4 is a diagram illustrating an example of the collision risk map. As shown in FIG. 4, the collision risk map includes a first time (TTC) until the host vehicle reaches the route intersection and a second time (TTV) until the object reaches the same point. It shows the relationship with the collision risk. The collision risk on the collision risk map is represented by the density of dot hatching for the convenience of display.

  The relationship between TTC and TTV and the risk of collision is explained as follows, assuming a case where an object crosses the front of the host vehicle. In a situation where the TTV is larger than the TTC (for example, A in FIG. 4), the host vehicle passes through the route intersection before the object crosses. Similarly, in a situation where the TTV is smaller than the TTC (for example, B in FIG. 4), the host vehicle passes through the route intersection after the object crosses. The collision risk is small as the difference between the two is large, and the difference is small. In particular, as the two approaches zero (for example, C in FIG. 4), the collision risk increases.

  By the way, in the driving assistance using the collision risk map, there may be a gap between the calculation result of the collision risk map and the determination result by the driver regarding the collision risk. FIG. 5 is a diagram illustrating an example of a situation where the collision risk is calculated. FIG. 6 is a diagram illustrating an example of calculating the collision risk using the collision risk map. FIG. 7 is a diagram illustrating an example of determination of the collision risk by the driver.

  FIG. 5 (a) shows a situation where two pedestrians P1 and P2 cross the crosswalk CW in front of the host vehicle C close to each other. FIG. 5B shows a situation where two pedestrians P1 and P3 cross the pedestrian crossing CW in front of the host vehicle C while being separated from each other. Pedestrians P1, P2, and P3 cross the course T of the host vehicle C at the same or substantially the same distance from the host vehicle C on the course T of the host vehicle C.

  In the situation shown in FIG. 5A, as shown in FIG. 6A, the collision risk with the pedestrian P1 is calculated as R1 (≈0) based on TTC1 and TTV1, and the collision with the pedestrian P2 occurs. The degree of risk is calculated as R2 (> R1) based on TTC2 and TTV2. In the situation shown in FIG. 5B, as shown in FIG. 6B, the collision risk with the pedestrian P1 is calculated as R1 (≈0) based on TTC1 and TTV1, and the collision with the pedestrian P3. The degree of risk is calculated as R3 (≈0) based on TTC3 and TTV3.

  Therefore, on the collision risk map, the collision risk is calculated to be high in the situation shown in FIG. 5A, and the collision risk is calculated to be almost 0 in the situation shown in FIG. 5B.

  On the other hand, in the situation shown in FIG. 5 (a) and FIG. 5 (b), as shown in FIG. 7 (a) and FIG. Not judge. That is, regardless of whether the pedestrians P1, P2, and P3 are close to each other or separated from each other, the collision risk is determined based on the time (TTC1, TTC2, TTC3) until the own vehicle C reaches the route intersection. To be judged. Therefore, from the driver's sense, it is determined that the collision risk is high in both the situation shown in FIG. 5A and the situation shown in FIG.

  Thus, when two or more objects cross the front of the host vehicle, a gap is likely to occur between the calculation result of the collision risk map and the determination result by the driver regarding the collision risk. When one object crosses, there is almost no gap between them.

  Here, in order to suppress such a gap, it is conceivable to calculate the collision risk by switching between the first calculation method and the second calculation method according to the number of detected objects. That is, when the number of detected objects is one, for example, the collision risk is calculated based on TTC and TTV, and when the number is two or more, for example, the collision risk is calculated based on TTC. is there.

  However, if the calculation method is suddenly switched according to a change in the number of detected objects, for example, as described below, there is a possibility that the driver may feel uncomfortable with respect to the determination of driving assistance. 8 and 9 are diagrams illustrating examples of situations in which a sense of incongruity may occur due to switching of calculation methods.

  In the situation shown in FIG. 8A, one pedestrian P1 crossing the pedestrian crossing CW in front of the host vehicle C is detected, and the collision risk is calculated by the first calculation method. However, in the situation shown in FIG. 8B immediately after that, the pedestrian P2 enters the detection area A and is detected, and the collision risk is calculated by the second calculation method. And if the difference in the collision risk calculated before and after the switching of the calculation method increases, the driving assistance determined based on the collision risk changes suddenly. As a result, the continuity of driving assistance is impaired, and the driver may feel uncomfortable with the determination of driving assistance.

  Similarly, in the situation shown in FIG. 9A, two pedestrians P1 and P2 crossing the pedestrian crossing CW ahead of the host vehicle C are detected, and the collision risk is calculated by the second calculation method. The However, in the situation of FIG. 9B immediately after that, the two pedestrians P1 and P2 are too close to each other to detect the pedestrian P2, and the collision risk is calculated by the first calculation method. In this case as well, the continuity of driving assistance is impaired, and the driver may feel uncomfortable with the determination of driving assistance.

  Therefore, in order to avoid the situation as shown in FIG. 8 and FIG. 9, the driving support device and the driving support method according to the embodiment of the present invention have a smaller number of detected objects as described below. Driving assistance is determined by weighting the first collision risk level with greater weight and the second collision risk level with increasing weight as the number of detected objects increases.

  Next, a driving support device and a driving support method according to an embodiment of the present invention will be described with reference to FIGS. The driving support device and the driving support method are devices and methods that support driving of the host vehicle, in particular, avoidance of collision between the host vehicle and the object. The object is a moving body that crosses the course of the host vehicle, such as a pedestrian, a bicycle, or another vehicle.

  FIG. 1 is a block diagram illustrating a driving assistance apparatus according to an embodiment of the present invention. The driving support device is mounted on the host vehicle and is configured with an electronic control unit 10 (ECU 10) as the center, as shown in FIG. A vehicle sensor 21, an object sensor 22, and a control output unit 23 are connected to the ECU 10.

  The vehicle sensor 21 detects the speed of the host vehicle and detects acceleration, steering angle, yaw rate, and the like as necessary. As the vehicle sensor 21, for example, a wheel speed sensor, an acceleration sensor, a steering angle sensor, and a yaw rate sensor are used.

  The object sensor 22 functions as an object detection unit that detects at least one object in the traveling direction of the host vehicle. The object sensor 22 detects the distance to the object and detects the relative speed as necessary. As the object sensor 22, for example, a millimeter wave radar, a laser radar, or an ultrasonic sensor is used.

  The control output unit 23 outputs a control signal used for driving support to at least one of a brake device or a steering device (not shown). As the control output unit 23, a brake actuator or a steering actuator is used.

  The ECU 10 includes a map storage unit 11, a driving support determination unit 12, and a driving support execution unit 13. The ECU 10 is composed mainly of a CPU, a ROM, and a RAM, and realizes the functions of the map storage unit 11, the driving support determination unit 12, and the driving support execution unit 13 through execution of programs by the CPU. Note that the functions of the map storage unit 11, the driving support determination unit 12, and the driving support execution unit 13 may be realized by two or more ECUs.

  The map storage unit 11 stores a collision risk map used for driving support. As described above, the collision risk map shows the relationship between the time required to reach the point where the course of the host vehicle and the course of the object intersect (the course intersection point) and the collision risk. The collision risk map shows the relationship between the first time (TTC) until the vehicle reaches the route intersection and the second time (TTV) until the object reaches the same point and the collision risk. Show. Note that TTC and TTV may be referred to as a collision prediction time in the traveling direction of the host vehicle and a collision prediction time in a direction crossing the traveling direction, particularly in a direction perpendicular to the traveling direction.

  The intersection is obtained as an intersection between the course of the host vehicle predicted based on the traveling state of the host vehicle and the course of the object predicted based on the moving state of the object. The TTC is obtained by dividing the distance on the route to the route intersection by the speed of the host vehicle. The TTV is obtained by dividing the distance on the route to the route intersection by the speed of the object.

  The driving support determination unit 12 determines driving support for the host vehicle based on a support determination value used for determination of driving support. The assistance determination value is calculated based on the collision risk, that is, the assistance request degree. The driving support determination unit 12 determines at least one of necessity or content of driving support based on the support determination value. The driving support determination unit 12 determines the content of driving support so that the driving support is promoted as the support determination value increases.

  The driving support determination unit 12 calculates the first collision risk by the first calculation method, and calculates the second collision risk by a second calculation method different from the first calculation method. The second calculation method has a smaller calculation amount than the first calculation method. The first collision risk is calculated by calculating TTC and TTV and applying them to the collision risk map. The second collision risk level is calculated based on a predetermined relationship between TTC and the collision risk level by calculating TTC. The second collision risk is, for example, 0 when the TTC exceeds the threshold, and increases as the TTC decreases when the TTC is equal to or less than the threshold.

  The driving assistance determination unit 12 calculates the assistance determination value by weighting the first collision risk level as the number of detected objects decreases and weighting the second collision risk level as the number of detected objects increases. To do. The calculation of the collision risk is performed by calculating the first and second collision risks for each at least one object crossing the path of the host vehicle. Alternatively, the support determination value is calculated by calculating the first collision risk for each object and calculating the second collision risk by regarding two or more objects as one object.

  The driving support execution unit 13 executes driving support determined based on the support determination value. Driving assistance includes notification assistance and control assistance. In the notification support, a driver is alerted through a human machine interface (HMI) (not shown) such as a display, a speaker, and a vibrator. In the control support, the control intervention for at least one of the brake device or the steering device (not shown) is performed through the control output unit 23.

  The control intervention includes at least one of automatic operation of braking or steering, operation assistance, and operation promotion. The promotion of driving assistance includes, for example, driving assistance activation, relaxation of activation conditions, early activation timing, and advancement / combination of assistance contents. Invoking driving assistance includes new start of assistance, switching of assistance contents, and addition of assistance contents.

  FIG. 2 is a flowchart showing the operation of the driving support method according to the embodiment of the present invention. The driving support device repeatedly executes the process shown in FIG. 2 for each set period.

  As shown in FIG. 2, the vehicle sensor 21 detects the speed of the host vehicle and supplies it to the ECU 10 (S11). The object sensor 22 detects at least one object in the traveling direction of the host vehicle (S12).

  The driving support determination unit 12 calculates TTC and TTV of the host vehicle and the object (S13). The driving support determination unit 12 calculates the first collision risk by applying TTC and TTV to the collision risk map (S14).

  The driving support determination unit 12 calculates the TTC of the host vehicle and the object (S15). The driving support determination unit 12 calculates the second collision risk based on a predetermined relationship between the TTC and the collision risk (S16).

  The first and second collision risk levels may be calculated in succession or simultaneously. When S15 is executed after S13, S15 may be omitted by using the calculation result of S13 in S16. In addition, when S13 is executed after S15, the calculation of TTC in S13 may be omitted by using the calculation result of S15 in S14.

The driving assistance determination unit 12 calculates the assistance determination value by weighting the first collision risk level as the number of detected objects decreases and weighting the second collision risk level as the number of detected objects increases. (S17). The support determination value is calculated by, for example, equation (1).
(Assistance determination value) = (1−a) · (first collision risk) + a · (second collision risk) (1)

  Here, a in the equation is a weighting coefficient (0 <a <1) corresponding to the number of detected objects. The weighting coefficient a is set so as to decrease as the number of detected objects decreases and increase as the number of detected objects increases. The weighting coefficient a may be set so as to increase monotonously according to the number of objects. For example, the weighting factor a may be set so as to increase monotonously until the number of objects is less than the threshold and to be constant above the threshold. For example, the driving support determination unit 12 prepares the weighting coefficient a as data indicating the correspondence between the number of objects and the coefficient value.

  FIG. 3 shows an example of the weighting coefficient a. That is, the weighting coefficient a is, for example, a = a1 (0 <a1 <1) when the number of detected objects is 1, and a = a2 (a1 <a2 <1) when the number of objects is two. ) When the number of objects is three or more, a = a3 (a2 <a3 <1) is set.

  The driving support determination unit 12 determines at least one of necessity or content of driving support based on the support determination value (S18). The driving support determination unit 12 promotes driving support as the support determination value increases. The driving assistance execution part 13 performs driving assistance as needed (S19). That is, when it is determined that the driving support is necessary, the driving support execution unit 13 executes the driving support determined based on the support determination value.

  As a result, even in the situation described with reference to FIGS. 8 and 9, the support determination value in consideration of the first collision risk level and the second collision risk level according to the change in the number of detected objects. Is calculated, and driving assistance is determined based on the assistance determination value. Therefore, since the calculation method does not suddenly change according to the change in the number of detected objects, it is possible to suppress the driver's uncomfortable feeling that occurs with respect to the determination of driving assistance.

  As described above, according to the driving support apparatus and the driving support method according to the embodiment of the present invention, the first collision risk calculated by the first calculation method according to the change in the number of detected objects. The assistance determination value is calculated in consideration of the degree and the first collision risk calculated by the second calculation method, and driving assistance is determined based on the assistance determination value. Therefore, since the calculation method does not suddenly change according to the change in the number of detected objects, it is possible to suppress the driver's uncomfortable feeling that occurs with respect to the determination of driving assistance.

  The above-described embodiment describes the best embodiment of the driving support device and the driving support method according to the present invention, and the driving support device and the driving support method according to the present invention are described in the present embodiment. It is not limited to things. The driving support device and the driving support method according to the present invention are modified from the driving support device and the driving support method according to the present embodiment without departing from the gist of the invention described in each claim, or applied to others. It may be a thing.

  For example, in the above embodiment, a case has been described in which the distance to an object is detected using a millimeter wave radar, a laser radar, an ultrasonic sensor, or the like, and the relative velocity is detected as necessary. However, the distance to the object and the relative speed may be detected using an imaging device such as a video camera or a stereo camera.

  DESCRIPTION OF SYMBOLS 10 ... Electronic control unit (ECU), 11 ... Map memory | storage part, 12 ... Driving assistance determination part, 13 ... Driving assistance execution part, 21 ... Vehicle sensor, 22 ... Object sensor, 23 ... Control output part.

Claims (7)

An object detection unit for detecting at least one object in the traveling direction of the host vehicle;
The first support request level is calculated by the first calculation method, and the second support request level is calculated by a second calculation method different from the first calculation method, so that the number of detected objects is small. As the number of detected objects increases, the first support request level is weighted more heavily, and the second support request level is weighted more heavily to calculate a support determination value. Based on the support determination value, the host vehicle A driving support determination unit that determines driving support for the vehicle,
A driving support apparatus comprising:   The driving support determination unit includes a first time until the host vehicle reaches a point where the course of the host vehicle and the course of the object intersect, and a first time until the object reaches the intersection. The driving support device according to claim 1, wherein the first support request level is calculated based on the second time, and the second support request level is calculated based on the first time. The object detection unit detects at least one of the objects crossing the course of the host vehicle,
The driving support determination unit calculates the first support request level and the second support request level for each object, and the support determination value is based on a calculation result of the support request level related to the at least one object. The driving support device according to claim 1, wherein the driving support device is calculated. The object detection unit detects two or more objects crossing the course of the host vehicle,
The driving support determination unit calculates the first support request level for each object, calculates the second support request level by regarding the two or more objects as one object, and calculates the two support request levels. The driving support device according to claim 1, wherein the support determination value is calculated based on the calculation result of the support request level related to the object.   The driving support according to claim 4, wherein the object detection unit detects the two or more objects crossing the path of the host vehicle at the same or substantially the same distance from the host vehicle on the path of the host vehicle. apparatus.   The driving support device according to any one of claims 1 to 6, wherein the second calculation method has a smaller calculation amount than the first calculation method. Detecting at least one object in the direction of travel of the vehicle,
The first support request level is calculated by the first calculation method, and the second support request level is calculated by a second calculation method different from the first calculation method, so that the number of detected objects is small. As the number of detected objects increases, the first support request level is weighted more heavily, and the second support request level is weighted more heavily to calculate a support determination value. Based on the support determination value, the host vehicle Determining driving assistance for the
Driving support method including.

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