JP7821086B2 - Braking control device - Google Patents

Description

The present invention relates to a braking control device that controls the braking operation of a vehicle.

Conventionally, when a collision between the vehicle and an object is predicted, a collision range at the time of the collision is calculated, and the collision range has a distribution calculated from the average value and standard deviation of the accumulated collision ranges. If the collision range is within the braking range of the braking range and no-braking range that are predetermined for the vehicle's presence area, braking operation of the vehicle is performed, but if it is only within the no-braking range, braking operation of the vehicle is not performed (see Patent Document 1). The braking control device described in Patent Document 1 can improve the accuracy of collision range prediction and the accuracy of determining whether to perform braking operation.

Japanese Patent Application Laid-Open No. 2021-172144

However, in a head-on collision after the vehicle has stopped, the collision occurs immediately after the vehicle starts moving, so there is a risk that sufficient time series data cannot be obtained to calculate the average value and standard deviation of multiple collision ranges, and the accuracy of calculating the distributed collision range may decrease. As a result, when determining whether to perform braking based on the distributed collision range, there is a risk that braking will not be performed when it should be, or that braking will be performed when it should not be.

The present invention was made to solve the above-mentioned problems, and its main objective is to provide a braking control device that can improve the accuracy of collision range prediction using a collision range calculated based on the average value and standard deviation of multiple collision ranges, while suppressing a decrease in collision range prediction accuracy in the event of a head-on collision after the vehicle has stopped.

The first means for solving the above problem is:
A braking control device (200) for controlling a braking operation of a host vehicle (VM),
a collision range calculation unit (240) that calculates a collision range (CA, CAd) of the host vehicle at a timing of collision between the host vehicle and an object (TG);
a start determination unit (245) that determines whether the vehicle is starting after stopping;
an execution determination unit (250) that, when it is determined by the start determination unit that the vehicle is not starting after stopping, determines whether or not to execute a braking operation for the vehicle based on a positional relationship between a first collision range (CAd) calculated based on an average value and a standard deviation of the plurality of collision ranges (CA) calculated by the collision range calculation unit and a braking range (BA1, BA2) set for the vehicle, and, when it is determined by the start determination unit that the vehicle is starting after stopping, determines whether or not to execute a braking operation for the vehicle based on a positional relationship between a second collision range (CA), which is the collision range currently calculated by the collision range calculation unit, and the braking range;
Equipped with.

With the above configuration, the collision range calculation unit calculates the collision range of the host vehicle at the timing of collision between the host vehicle and the object. Note that the collision range may be the range of the host vehicle that collides with the object, or the point on the host vehicle that collides with the object.

The start determination unit determines whether the host vehicle is starting after stopping. If the start determination unit determines that the host vehicle is not starting after stopping, the execution determination unit determines whether to execute a braking operation for the host vehicle based on the positional relationship between a first collision area calculated based on the average value and standard deviation of the multiple collision areas calculated by the collision area calculation unit and the braking range set for the host vehicle. Therefore, if the host vehicle is determined not to be starting after stopping and sufficient time-series data is available to calculate the average value and standard deviation of the multiple collision areas, the prediction accuracy of the first collision area can be improved. Then, an appropriate determination can be made as to whether to execute a braking operation for the host vehicle based on the positional relationship between the first collision area and the braking range set for the host vehicle.

On the other hand, when the departure determination unit determines that the host vehicle is starting after stopping, the execution determination unit determines whether to execute a braking operation for the host vehicle based on the positional relationship between the second collision range, which is the collision range currently calculated by the collision range calculation unit, and the braking range. Therefore, when the host vehicle is determined to be starting after stopping and sufficient time series data is not available to calculate the average value and standard deviation of multiple collision ranges, the first collision range is not used, and the second collision range, which is the collision range currently calculated, can be used. Therefore, it is possible to prevent a decrease in the prediction accuracy of the collision range in the event of a head-on collision after the host vehicle has stopped. Then, it is possible to appropriately determine whether to execute a braking operation for the host vehicle based on the positional relationship between the second collision range and the braking range.

When the host vehicle is starting from a stop, its speed increases rapidly, resulting in large fluctuations in the collision range. Therefore, if the same braking range is set for the host vehicle when it is starting from a stop as when it is not starting from a stop, it may not be possible to properly determine whether to brake the host vehicle.

In this regard, in the second means, the execution determination unit sets a first braking range as the braking range when the start determination unit determines that the vehicle is not starting after stopping, and sets a second braking range different from the first braking range as the braking range when the start determination unit determines that the vehicle is starting after stopping. With this configuration, when it is determined that the vehicle is starting after stopping, it is possible to appropriately determine whether to execute a braking operation for the host vehicle based on the second braking range different from the first braking range when it is determined that the vehicle is not starting after stopping.

Specifically, as in the third means, the execution determination unit may be configured to determine that a braking operation for the host vehicle is to be performed when the start determination unit determines that the host vehicle is not starting after stopping and the first collision range is within the first braking range, and to determine that a braking operation for the host vehicle is to be performed when the start determination unit determines that the host vehicle is starting after stopping and the second collision range is within the second braking range.

When the vehicle starts moving after stopping, the vehicle's speed increases rapidly, making it more likely that the collision range will shift toward the rear end of the vehicle. In this case, if the braking range is set wide from the front to the rear end of the vehicle, the collision range may enter the braking range and the vehicle may be braked, which could actually make the vehicle more likely to collide with an object.

In this regard, in the fourth means, the range in which the second braking range is set from the front end to the rear end of the host vehicle is narrower than the range in which the first braking range is set from the front end to the rear end of the host vehicle. Therefore, when it is determined that the host vehicle is starting after stopping, a second braking range in which the range set from the front end to the rear end of the host vehicle is narrower than the first braking range can be set for the host vehicle. Therefore, it is possible to prevent unnecessary braking operations from being performed on the host vehicle in the event of a head-on collision after the host vehicle has stopped.

In the fifth means, the departure determination unit determines that the host vehicle is starting after stopping if the host vehicle's speed increases from a state below 0 to a state above 0, the time elapsed since the host vehicle's speed increased above 0 is shorter than a predetermined time, the host vehicle's speed is lower than a predetermined speed higher than 0, and an object is approaching the host vehicle. With this configuration, if the time elapsed since the host vehicle's speed increased above 0 is longer than a predetermined time, it can be determined that the host vehicle is not starting after stopping. Furthermore, if the host vehicle's speed increases above a predetermined speed higher than 0, it can be determined that the host vehicle is not starting after stopping. Furthermore, if no object is approaching the host vehicle, it can be determined that the host vehicle is not starting after stopping. Therefore, it is possible to appropriately determine that the host vehicle is starting after stopping, i.e., a situation in which a head-on collision may occur after the host vehicle has stopped.

FIG. 1 is a configuration diagram of a vehicle control system. FIG. 2 is an explanatory diagram of a vehicle existence region on an XY plane of a two-dimensional coordinate system. FIG. 2 is an explanatory diagram of a target existence region on an XY plane of a two-dimensional coordinate system. FIG. 2 is an explanatory diagram of a vehicle solid and a target solid in a three-dimensional coordinate system. 10 is an explanatory diagram showing collision determination between the host vehicle and a target based on the host vehicle solid and the target solid; FIG. FIG. 4 is an explanatory diagram showing the relationship between a collision position and a collision range. FIG. 10 is an explanatory diagram showing a first example of a collision range. FIG. 10 is an explanatory diagram showing a second example of a collision range. FIG. 10 is an explanatory diagram showing a third example of the collision range. FIG. 10 is an explanatory diagram showing a fourth example of the collision range. FIG. 10 is an explanatory diagram showing an example of a one-dimensional coordinate system used for braking determination based on a collision range. FIG. 10 is an explanatory diagram showing braking determination based on a collision range. FIG. 10 is a first explanatory diagram showing braking determination based on a collision range. FIG. 10 is a second explanatory diagram showing braking determination based on the collision range. FIG. 2 is an explanatory diagram showing a collision at an intersection when the host vehicle is traveling normally. FIG. 10 is an explanatory diagram showing the time variation of the collision range when the host vehicle is traveling normally. FIG. 2 is an explanatory diagram showing a collision at an intersection when the host vehicle starts after stopping. FIG. 10 is an explanatory diagram showing the time variation of the collision range when the host vehicle starts after stopping. 10 is a flowchart illustrating a braking determination procedure.

Below, one embodiment of the brake control device for a vehicle control system will be described with reference to the drawings.

As shown in FIG. 1, the vehicle control system 10 includes an object detection device 110 and a braking control ECU 200, which corresponds to a braking control device.

The object detection device 110 transmits millimeter waves and detects the position of targets around the vehicle and the relative speed of the targets relative to the vehicle from the waves reflected by the transmitted millimeter waves from the objects (hereinafter also referred to as "targets"). The object detection device 110 includes a millimeter-wave radar sensor 111 and a radar ECU 112.

The millimeter-wave radar sensors 111 are attached, for example, to the front and rear of the vehicle, and emit millimeter waves around the vehicle and receive the reflected waves. The millimeter-wave radar sensor 111 outputs a reflected wave signal related to the received reflected waves to the radar ECU 112.

The radar ECU 112 calculates the position of targets around the vehicle and the relative speed of the targets with respect to the vehicle from the reflected wave signal output from the millimeter-wave radar sensor 111. The radar ECU 112 outputs the calculated target position and the relative speed of the targets with respect to the vehicle to the brake control ECU 200. The radar ECU 112 is configured by a computer including, for example, a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), and an input/output interface. ECU is an abbreviation for Electronic Control Unit.

The brake control ECU 200 is connected to a yaw rate sensor 120, a steering angle sensor 130, a wheel speed sensor 140, and a collision suppression device 300. The yaw rate sensor 120 is located, for example, at the center of the vehicle, and outputs a yaw rate signal corresponding to the rate of change in the steering amount of the vehicle to the brake control ECU 200. The steering angle sensor 130 is attached, for example, to the vehicle's steering rod, and outputs a steering angle signal corresponding to changes in the steering angle of the steering wheel caused by driver operation to the brake control ECU 200. The wheel speed sensor 140 is attached, for example, to the wheel of the vehicle, and outputs a wheel speed signal corresponding to the wheel speed of the vehicle to the brake control ECU 200.

The collision suppression device 300 is a device that suppresses a collision of a target with the vehicle, and in this embodiment, it is equipped with a braking device 310 and a seatbelt actuator 320.

The braking device 310 controls braking by the brake actuator. Specifically, it controls the braking force of the brake actuator in accordance with the deceleration signal output from the brake control ECU 200. By controlling the braking force of the brake actuator, the amount of deceleration of the vehicle is adjusted. The seat belt actuator 320 operates the seat belt retractor in accordance with the activation signal output from the brake control ECU 200, and retracts and tensions the seat belt.

The brake control ECU 200 determines whether or not the target will collide with the host vehicle based on the target position and the target's relative speed relative to the host vehicle output from the object detection device 110. If the target will collide with the host vehicle, the brake control ECU 200 determines whether or not to execute braking operation by the brake device 310 based on a collision area including the collision point. Specifically, the brake control ECU 200 calculates a host vehicle solid, which is a solid that indicates the transition of the host vehicle's existence area on the host vehicle's estimated path, in a virtual three-dimensional coordinate system. The brake control ECU 200 also calculates a target solid, which is a solid that indicates the transition of the target's existence area on the target's estimated path, based on the target position and the target's relative speed relative to the host vehicle output from the object detection device 110, in the three-dimensional coordinate system. The brake control ECU 200 then determines whether or not the host vehicle will collide with the target based on whether or not the host vehicle solid intersects with the target solid. Furthermore, the brake control ECU 200 calculates the collision range from the position of the target presence area within the collision judgment range surrounding the host vehicle presence area at the time of collision between the host vehicle and the target. The brake control ECU 200 then controls whether or not to perform braking operation depending on the collision range. The target position and the target's relative speed with respect to the host vehicle output from the object detection device 110 correspond to "target information" or "object information."

When the brake control ECU 200 determines that a target will collide with the vehicle and executes braking, it activates the collision suppression device 300 to execute collision suppression control for the vehicle. For example, the brake control ECU 200 executes collision suppression control by generating and outputting a deceleration signal to the braking device 310 and an activation signal to the seatbelt actuator 320.

The collision detection and braking control functions of the braking control ECU 200 are realized by functional components such as the host vehicle movement calculation unit 210, target movement calculation unit 220, collision detection unit 230, collision area calculation unit 240, host vehicle stop and start detection unit 245, and braking detection unit 250. The host vehicle movement calculation unit 210 is realized by the host vehicle path estimation unit 211, host vehicle area calculation unit 212, and host vehicle information calculation unit 213. The target movement calculation unit 220 is realized by the target path estimation unit 221, target area calculation unit 222, and target information calculation unit 223. The braking control ECU 200 is configured by a computer equipped with a CPU, ROM, RAM, input/output interfaces, etc., and each of the functional components is realized by the CPU executing an application (program) corresponding to each function.

As described below, the vehicle transition calculation unit 210 calculates a vehicle solid, which is a solid that indicates the transition of the vehicle's existence area on the vehicle's estimated route, in a virtually formed three-dimensional coordinate system. The target transition calculation unit 220 also calculates a target solid, which is a solid that indicates the transition of the target's existence area on the target's estimated route, calculated from the target position output from the object detection device 110 and the target's relative speed with respect to the vehicle, in a three-dimensional coordinate system, as described below.

In the host vehicle progress calculation unit 210, the host vehicle path estimation unit 211 calculates a host vehicle estimated path PA1 indicating the estimated path of the host vehicle from the rate of change in the steering amount of the host vehicle and the host vehicle speed. In this embodiment, the host vehicle path estimation unit 211 calculates an estimated curve radius of the host vehicle from the yaw rate of the host vehicle calculated using the yaw rate signal from the yaw rate sensor 120 and the host vehicle speed calculated using the wheel speed signal from the wheel speed sensor 140. The route that the host vehicle will take if it travels along the calculated estimated curve radius is then calculated as the host vehicle estimated path PA1. Note that the rate of change in the steering amount of the host vehicle may also be calculated from the steering angle signal from the steering angle sensor 130.

The vehicle area calculation unit 212 calculates a vehicle presence area EA1 that indicates the area in which the vehicle exists at each fixed time on the vehicle's estimated path PA1 on the XY plane of a two-dimensional coordinate system defined by the distance Y in the current vehicle travel direction and the distance X in the vehicle width direction. In this embodiment, the vehicle area calculation unit 212 calculates the vehicle presence area EA1 at each position on the vehicle's estimated path PA1 during the period from the current time T0 (hereinafter also referred to as "current T0") to the estimated end time TN.

The upper part of Figure 2 shows the host vehicle existence area EA1 calculated for the host vehicle VM at the current time T0, i.e., when the elapsed time T is 0. In this embodiment, the host vehicle existence area EA1 is defined as a rectangular area that includes the entire perimeter of the host vehicle VM when viewed from above. The host vehicle area calculation unit 212 defines the rectangular area that forms the host vehicle existence area EA1 in accordance with vehicle specifications that indicate the size of the host vehicle. For example, the host vehicle existence area EA1 at the current time T0 is defined so that the intersection (0,0) of the X axis and Y axis is the reference position P0 of the host vehicle VM. Furthermore, the reference position P0 of the host vehicle VM is set to be the center in the vehicle width direction in front of the host vehicle.

The lower part of Figure 2 shows a comparison of the vehicle presence area EA1 at current time T0 shown in the upper part of Figure 2 with the vehicle presence area EA1 at a future time T of T1 from current time T0. To facilitate explanation, the lower diagram shows the vehicle presence area EA1 at current time T0 and the vehicle presence area EA1 at a future time T of T2 from current time T0 (T2 > T1) with dashed lines.

The host vehicle existence area EA1, which is an elapsed time T1 from the current time T0, indicates the host vehicle existence area after the elapsed time T1 from the host vehicle position at the current time T0 when the host vehicle VM moves along the host vehicle estimated path PA1. For example, the host vehicle area calculation unit 212 calculates, based on the host vehicle estimated path PA1 calculated for the host vehicle position at the current time T0 and the host vehicle speed, the passing position on the host vehicle estimated path PA1 after the elapsed time Tn (n is an integer greater than or equal to 0 and less than or equal to N) from the reference position P0 of the host vehicle VM at the current time T0. Then, a rectangular area with each passing position as the reference position Pn is calculated as the host vehicle existence area EA1, which is an elapsed time Tn from the current time T0. In this embodiment, the orientation of the host vehicle existence area EA1 at each elapsed time Tn is defined as the orientation of the tangent to the host vehicle estimated path PA1 at each reference position Pn.

The host vehicle information calculation unit 213 calculates a host vehicle solid D1 that indicates the progression of the host vehicle existence area EA1 by interpolating multiple host vehicle existence areas EA1 in a three-dimensional coordinate system defined by the distance Y in the host vehicle's traveling direction, the distance X in the vehicle width direction, and the elapsed time T from the current time T0. In the three-dimensional coordinate system shown in Figure 4, the point (0,0,0) indicates the host vehicle's reference position P0 at the current time T0. The host vehicle solid D1 indicates the progression of the host vehicle existence area EA1 over the elapsed time T in the three-dimensional coordinate system. In Figure 4, the host vehicle solid D1 is calculated for the predicted time width from the current time T0 to the estimated end time TN.

In this embodiment, the host vehicle information calculation unit 213 converts the calculated multiple host vehicle existence areas EA1 into information in a three-dimensional coordinate system. Then, in the three-dimensional coordinate system, the host vehicle solid D1 is calculated by linearly interpolating the four corners between adjacent host vehicle existence areas EA1 in the direction of the T axis, which determines the elapsed time.

In the target transition calculation unit 220, the target path estimation unit 221 calculates the target estimated path PA2, which indicates the estimated path of the target, from the position of the target detected by the object detection device 110 and the relative speed of the target with respect to the host vehicle. For example, the target path estimation unit 221 calculates the movement trajectory of the target from changes in the target position detected by the object detection device 110, and sets this movement trajectory as the target estimated path PA2. Note that the target estimated path PA2 corresponds to the "estimated path of the object."

The target area calculation unit 222 calculates a target presence area EA2 that indicates the area in which a target exists at each fixed time on the target estimated path PA2 on the XY plane of a two-dimensional coordinate system defined based on the current vehicle position. The target presence area EA2 indicates the area in which a target exists at each fixed time when the target moves along the target estimated path PA2. The target presence area EA2 corresponds to the "object presence area."

The upper part of Figure 3 shows the target presence area EA2 calculated for the target TG at the current time T0. The target presence area EA2 on the XY plane at the current time T0 indicates the presence area of the target TG detected by the object detection device 110 at the current vehicle position. In this embodiment, another vehicle is shown as an example of the target TG. The target area calculation unit 222 sets the target presence area EA2 as a rectangular area that includes the entire perimeter of the target when the target TG is viewed from above. For example, the rectangular area that forms the target presence area EA2 is set according to the size of the target calculated by the object detection device 110.

The bottom part of Figure 3 shows a comparison of the target presence area EA2 at current time T0 shown in the top part of Figure 3 with the target presence area EA2 at current time T0, which is the elapsed time T1. For example, the target area calculation unit 222 calculates the passing position on estimated target path PA2 after elapsed time Tn from the reference position B0 of the target TG at current time T0, based on the estimated target path PA2 and the relative speed of the target relative to the host vehicle. Then, a rectangular area with each passing position as the reference position Bn is calculated as the target presence area EA2 at current time Tn.

The target information calculation unit 223 interpolates multiple target presence areas EA2 in a three-dimensional coordinate system defined based on the current vehicle position at T0 to calculate a target solid D2, which is a solid that shows the progression of the target presence areas EA2. The target solid D2 shown in FIG. 4 indicates the progression of the target presence areas EA2 over elapsed time T in the three-dimensional coordinate system. In this embodiment, the target information calculation unit 223 converts the calculated multiple target presence areas EA2 into information in the three-dimensional coordinate system. Then, in the three-dimensional coordinate system, the target solid D2 is calculated by linearly interpolating the four corners between adjacent target presence areas EA2 in the direction of the T axis, which determines the elapsed time. The target presence areas EA2 correspond to the "object presence areas," and the target solid D2 corresponds to the "object solid."

The collision determination unit 230 determines whether the host vehicle will collide with the target based on whether the host vehicle solid D1 and the target solid D2 intersect. In this embodiment, the collision determination unit 230 calculates a first determination area DA1 indicating the host vehicle existence area EA1 for a set elapsed time T using the host vehicle solid D1. It also calculates a second determination area DA2 indicating the target existence area EA2 for the same elapsed time T as the first determination area DA1 using the target solid D2. If there is an overlapping area between the calculated first and second determination areas DA1 and DA2 for the same elapsed time T, it determines that the host vehicle solid D1 and the target solid D2 intersect.

When the host vehicle solid D1 and the target solid D2 intersect, as shown in Figure 5, there is an overlapping area CPA between the first judgment area DA1 and the second judgment area DA2 in the XY plane at the same elapsed time Ta. Therefore, the collision determination unit 230 determines that the host vehicle and the target will collide when there is an overlapping area CPA between the first judgment area DA1 and the second judgment area DA2 at the same elapsed time T.

On the other hand, if the host vehicle solid D1 and the target solid D2 do not intersect, there is no overlapping area CPA between the first judgment area DA1 and the second judgment area DA2 in the XY plane at any elapsed time T. Therefore, the collision determination unit 230 determines that there will be no collision between the host vehicle and the target if there is no overlapping area CPA between the first judgment area DA1 and the second judgment area DA2 at the same elapsed time T.

In this embodiment, the collision determination unit 230 calculates first and second determination areas DA1 and DA2 for the same elapsed time T at predetermined elapsed time intervals ΔT between the current time T0 and the estimated end time TN. The calculated first and second determination areas DA1 and DA2 for the same elapsed time T are then used to determine whether or not there is an overlapping area CPA.

As described below, the collision range calculation unit 240 calculates a collision range CA including a collision point CP as the collision position where the target TG will collide with the host vehicle VM, based on the positional relationship between the host vehicle existence area EA1 and the target existence area EA2 at the elapsed time Ta when the collision is predicted (hereinafter also referred to as "collision timing Ta"). Note that the collision point CP and collision range CA are the collision point and collision range of the host vehicle. Then, as described below, the braking determination unit 250 controls whether or not to perform a braking operation for the host vehicle depending on the positional relationship between the collision range CA and a predetermined no-braking range NBA for the host vehicle.

To identify the positions of the host vehicle presence area EA1 and the target presence area EA2 at the collision timing Ta, the collision range calculation unit 240 uses coordinates on the XY plane of a two-dimensional coordinate system defined by the distance Y in the host vehicle's traveling direction and the distance X in the vehicle width direction, as shown in Figure 6. The XY plane shown in Figure 6 is defined so that the reference position Pa of the host vehicle VM at the collision timing Ta is the intersection (0,0) of the X axis and the Y axis, and the host vehicle presence area EA1 and the target presence area EA2 at the collision timing Ta can be expressed by the coordinates of their positions on the defined XY plane. The position of the host vehicle presence area EA1 can be expressed by the coordinates of the four corner points on the defined XY plane: the left front point Vfl, the right front point Vfr, the left rear point Vrl, and the right rear point Vrr. Similarly, the target existence area EA2 can be expressed by the coordinates of the four corner points of the defined XY plane: the front left point Tfl, the front right point Tfr, the rear left point Trl, and the rear right point Trr. The XY plane defined at the current time T0 (see FIG. 2) may also be used to represent the positions of the host vehicle existence area EA1 and the target existence area EA2 at the collision timing Ta. However, setting the reference position Pa of the host vehicle VM at the collision timing Ta to the intersection (0,0) of the X and Y axes reduces the amount of data handled for calculating the collision area, thereby reducing the calculation load on the collision area calculation unit 240.

The collision area CA is determined by the positional relationship between the host vehicle presence area EA1 and the target presence area EA2 at the collision timing Ta; specifically, as shown in Figures 7 to 10, for example, the positional relationship between the target presence area EA2 and the collision judgment area CJ set on the periphery of the host vehicle VM's host vehicle presence area EA1.

The collision detection range CJ set around the periphery of the host vehicle presence area EA1 includes a left collision detection range CJl, a right collision detection range CJr, a front collision detection range CJf, and a rear collision detection range CJr of the host vehicle presence area EA1. The left collision detection range CJl of the host vehicle VM is set as a rectangular area specified by the coordinates of two points obtained by shifting the two left corner points Vfl and Vrl of the host vehicle presence area EA1 inward in the X direction by a predetermined margin, and the coordinates of two points obtained by shifting the two corner points Vfl and Vrl outward in the X direction by a predetermined width. Similar to the left collision detection range CJl, the right collision detection range CJr of the host vehicle VM is set as a rectangular area specified by the coordinates of four points based on the two right corner points Vfr and Vrr of the host vehicle presence area EA1. The collision detection range CJf in front of the host vehicle VM is set to a rectangular area specified by the coordinates of two points obtained by shifting the two front corner points Vfl, Vfr of the host vehicle existence area EA1 inward in the Y direction by a predetermined margin, and the coordinates of two points obtained by shifting the two corner points Vfl, Vfr outward in the Y direction by a predetermined width. Similar to the front collision detection range CJf, the collision detection range CJb in the rear of the host vehicle VM is set to a rectangular area specified by the coordinates of four points based on the two rear corner points Vrl, Vrr of the host vehicle existence area EA1.

As shown in Figure 7, when a target TG collides with the left side of the host vehicle VM, the distance in the Y direction between two target endpoints CJPr and CJPl, which are the endpoints of the target presence area EA2 within the left collision detection range CJl, is defined as the collision area CA. One target endpoint CJPr is the right endpoint as viewed from the host vehicle VM side, and CJPl is the left endpoint as viewed from the front. The distance in the Y direction between the two target endpoints CJPr and CJPl corresponds to the range represented by the distance between two positions CAr and CA1 obtained by projecting the two target endpoints CJPr and CJPl of the target presence area EA2 within the collision detection range CJl onto the edge of the host vehicle presence area EA1 that is parallel to the outer edge of the collision detection range CJl.

Although not shown in the figure, when a target TG collides with the right side of the host vehicle VM, the distance in the Y direction between the two target endpoints CJPr and CJPl of the target presence area EA2 that are within the right-side collision judgment range CJr is similarly defined as the collision range CA.

Furthermore, as shown in Figure 8, when a target TG collides with the front side of the host vehicle VM, the distance in the X direction between two target end points CJPr and CJPl, which are the end points of the target presence area EA2 within the front collision detection range CJf, is defined as the collision area CA. The distance in the X direction between the two target end points CJPr and CJPl corresponds to the range represented by the distance between two positions CAr and CA1 obtained by projecting the two target end points CJPr and CJPl of the target presence area EA2 within the collision detection range CJf onto the edge of the host vehicle presence area EA1 that is parallel to the outer edge of the collision detection range CJf.

Although not shown in the figure, when a target TG collides with the rear side of the host vehicle VM, the distance in the X direction between the two target endpoints CJPr and CJPl of the target presence area EA2 that are within the rear collision judgment range CJb is also defined as the collision range CA.

Furthermore, as shown in Figure 9, if a target TG collides with point Vfl, the front left corner of the host vehicle VM, there is a possibility that the target presence area EA2 will straddle both the left collision detection range CJl and the front collision detection range CJf. In this case, the collision area CA is defined as the area from the target end point CJPl, which is the farthest from the collision point CP in the target presence area EA2 within the left collision detection range CJl, to the target end point CJPr, which is the farthest from the collision point CP in the target presence area EA2 within the front collision detection range CJf. Specifically, the collision area CA is defined as both the distance in the Y direction from one target end point CJPl to the top end of the left collision detection range CJl, and the distance in the X direction from the left end of the front collision detection range CJf to the other target end point CJPr. The distance in the Y direction from one target endpoint CJPl to the top end of the left collision detection range CJl corresponds to the range represented by the distance between positions CA1 and Vfl when the target endpoint CJPl within the left collision detection range CJl and the top end point of the outer edge of the collision detection range CJl are projected onto the side of the host vehicle existence area EA1 that is parallel to the outer edge of the collision detection range CJl. The distance in the X direction from the left end of the front collision detection range CJf to the other target endpoint CJPr corresponds to the range represented by the distance between positions CAr and Vfl when the target endpoint CJPr within the front collision detection range CJf and the left end point of the outer edge of the collision detection range CJf are projected onto the side of the host vehicle existence area EA1 that is parallel to the outer edge of the collision detection range CJf.

Although not shown in the figure, if a target TG collides with another corner of the host vehicle VM and the target presence area EA2 straddles both collision judgment ranges, the collision area CA will similarly be the range from the target endpoint farthest from the collision point CP in the target presence area EA2 within one collision judgment range to the target endpoint farthest from the collision point CP in the target presence area EA2 within the other collision judgment range.

Furthermore, Figures 7 to 9 show examples of the collision area CA when a target TG collides with the host vehicle VM. However, as shown in Figure 10, the collision area CA when the host vehicle VM collides with the target TG can also be defined as the area represented by the distance between two target endpoints CJPr and CJPl of the target presence area EA2 that falls within the host vehicle's collision detection area. Figure 10 shows an example of the collision area CA when the host vehicle VM collides with the right side of the target TG. In this case, the target presence area EA2 extends from the left end to the right end of the front collision detection area CJf, so the two ends of the outer edge of the collision detection area CJf are the two target endpoints CJPr and CJPl of the target presence area EA2 that fall within the collision detection area CJf. The distance between the two target endpoints CJPr and CJPl in the X direction corresponds to the range represented by the distance between the two positions CAr and CA1 obtained by projecting the two target endpoints CJPr and CJPl of the target presence area EA2 within the collision detection range CJl onto the edge of the host vehicle presence area EA1 that is parallel to the outer edge of the collision detection range CJf. Note that the range represented by the distance between the two positions CAr and CA1 corresponds to the entire range of the collision detection range CJf in the X direction.

Although not shown in the figure, the collision area CA when the host vehicle VM collides with another surface of the target TG is also defined as the area from one target endpoint CJPl to the other CJPr in the target existence area EA2 that is within the host vehicle's collision judgment range.

As described above, the calculated end positions CA1 and CAr of the collision area CA are expressed in coordinates on the XY plane, with the Y coordinate values changing in the left collision detection area CJ1 and right collision detection area CJr of the host vehicle VM, and the X coordinate values changing in the front collision detection area CJf and rear collision detection area CJb. When the braking determination unit 250 uses the collision area CA expressed in coordinates on the XY plane to make a determination regarding the host vehicle's braking operation (described below), it must take into account two-dimensional changes in the X and Y directions, making the processing complicated. Therefore, the collision area calculation unit 240 converts the end positions CA1 and CAr of the collision area CA, which are expressed in a two-dimensional coordinate system, into coordinates in a one-dimensional coordinate system.

The one-dimensional coordinate system used is a coordinate system that expands the outer edges of the vehicle existence area EA1 onto which the two target endpoints CJPl and CJPr (see Figures 7 to 10) corresponding to the positions CA1 and CAr of the collision area CA are projected. In this embodiment, as shown in Figure 11, the lengths of the front edge Sf, left edge Sl, rear edge Sb, and right edge Sr of the vehicle existence area EA1 are each defined as "1 (100%)", the center position of the front edge Sf is defined as the origin "0", and the center position of the rear edge Sb is defined as "-2 (-200%)" in the counterclockwise direction and "2 (200%)" in the clockwise direction. However, this is not limited to this, and various settings are possible.

For example, in the collision state shown in Figure 9, suppose the difference in the Y coordinate between the left front point Vfl and the left end position CA1 of the collision area CA is 10% of the difference in the Y coordinate between the left front point Vfl and the left rear point Vrl. In this case, as shown in Figure 11, the coordinate of the left end position CA1 is converted to -0.6. Also, in the collision state shown in Figure 9, suppose the difference in the X coordinate between the left front point Vfl and the right end position CAr of the collision area CA is 20% of the difference in the X coordinate between the left front point Vfl and the right front point Vfr. In this case, as shown in Figure 11, the coordinate of the right end position CAr is converted to -0.3.

As shown in FIG. 12 , the braking determination unit 250 (execution decision unit) determines whether to execute braking of the host vehicle by the braking device 310 based on the positional relationship between the host vehicle's collision area CA calculated by the collision area calculation unit 240 and the host vehicle's no-braking area NBA, and controls the host vehicle's braking operation. The host vehicle's no-braking area NBA is a predetermined area relative to the host vehicle's presence area EA1, and the area excluding the no-braking area NBA is predetermined as the braking-enabled area BA. The no-braking area NBA is set to an area where it is preferable to leave it up to the driver's intention to accelerate and not perform automatic braking, for example, an area corresponding to the trunk position at the rear of the vehicle, because decelerating the host vehicle increases the possibility of colliding with an area where occupants are inside the vehicle. The braking-enabled area BA is an area where it is preferable to decelerate the host vehicle to reduce the possibility of a collision.

As shown in the left column of Figure 12, if the collision area CA is included only in the no-braking area NBA, the braking determination unit 250 deactivates braking by the braking device 310 and does not perform braking operation on the host vehicle VM, since the target object TG will collide only with the no-braking area NBA of the host vehicle VM.

Furthermore, as shown in the right column of Figure 12, if the collision area CA is included only in the braking area BA, the braking determination unit 250 activates the braking operation of the braking device 310 to perform braking of the host vehicle, since the target object TG will collide only with the braking area BA of the host vehicle VM.

Furthermore, as shown in the center column of Figure 12, if the collision area CA is included in both the no-braking area NBA and the braking-enabled area BA, the braking determination unit 250 determines that the target object TG will collide not only with the no-braking area NBA but also with the braking-enabled area BA, and therefore prioritizes the operation of the braking operation, activates the braking device 310, and performs braking on the host vehicle.

The above is the basic concept for determining whether to perform braking for the host vehicle. Furthermore, in this embodiment, the method for determining whether to perform braking for the host vehicle is different depending on whether the host vehicle is running normally or when the host vehicle starts moving after stopping.

First, we will explain how the brake control ECU 200 determines whether to perform a braking operation on the host vehicle when the host vehicle is traveling normally. Normal traveling of the host vehicle includes when the host vehicle is traveling at a substantially constant speed, when the host vehicle is accelerating from a traveling state, when the host vehicle is decelerating from a traveling state, etc. Note that normal traveling of the host vehicle corresponds to a case other than when the host vehicle is starting off after stopping, as described below.

When the host vehicle is driving normally, the collision area calculation unit 240 calculates the collision area CA of the host vehicle and then stores the calculated collision area CA in a predetermined memory area. Next, it calculates the average value CAm and standard deviation σ of a certain number (plurality) of accumulated collision areas CA. Specifically, it calculates the average value CAlm and standard deviation σl of the left edge position CA1 of the collision area CA, and the average value CArm and standard deviation σr of the right edge position CAr.

When the host vehicle is traveling normally, the braking determination unit 250 determines whether the collision range CAd, which is calculated by adding the standard deviation σ to the average value CAm, is included only in the no-braking range NBA. The collision range CAd (first collision range) is a range having a distribution calculated from the average value CAm and the standard deviation σ, and is, for example, a range obtained by adding a ±3σ distribution to the average value CAm of the collision range CA. Specifically, as shown in FIG. 13, the collision range CAd is the distance between the left end position (CAlm-3σl), which is expanded outward by the distribution 3σl from the average value CAlm of the left end position CAl, and the right end position (CArm+3σr), which is expanded outward by the distribution 3σr from the average value CArm of the right end position CAr.

If the collision range CAd is included only in the no-braking range NBA, the braking determination unit 250 deactivates the braking operation of the host vehicle by the braking device 310. On the other hand, if the collision range CAd is not included only in the no-braking range NBA, i.e., if it is included only in the braking-enabled range BA (see FIG. 13), or if it is included in both the braking-enabled range BA and the no-braking range NBA (see FIG. 14), the braking determination unit 250 executes braking operation of the host vehicle by the braking device 310. Note that the case where the collision range CAd is included only in the braking-enabled range BA and the case where the collision range CAd is included in both the braking-enabled range BA and the no-braking range NBA correspond to the case where the collision range CAd is included in the braking-enabled range BA.

In this way, during normal driving of the host vehicle, the distributed collision area CAd is included only in the no-braking area NBA, and if it is predicted that the target TG will collide only with the no-braking area NBA of the host vehicle VM, the braking operation of the host vehicle VM is deactivated and no braking operation is performed for the host vehicle VM. This improves the accuracy of collision area prediction and makes it possible to appropriately determine whether or not to perform braking operation.

As shown in Figure 15, assume that the host vehicle VM is traveling straight ahead at a road intersection, and the target object TG is traveling straight from the left to the right of the host vehicle. In this case, a certain amount of time can be ensured before the host vehicle VM and the target object TG collide. Therefore, there is sufficient time series data to accurately calculate the average value CAm and standard deviation σ of multiple collision areas CA, improving the accuracy of calculating the distributed collision area CAd.

Furthermore, during normal driving, acceleration and deceleration are often gradual. For this reason, the average value CAm of multiple collision areas CA tends to be stable, and the standard deviation σ tends to be small. Therefore, the collision area CAd, which has a distribution that is the range obtained by adding ±3σ distribution to the average value CAm of multiple collision areas CA, fluctuates little over time, as shown in Figure 16.

In contrast, the inventors of the present application have noticed that the following problem occurs when the host vehicle starts moving after stopping. As shown in Figure 17, assume that the host vehicle VM stops just before the intersection at a road intersection and then starts moving, and a target object TG is moving straight from the left to the right of the host vehicle near the intersection. In this case, a head-on collision is likely to occur after the host vehicle stops, and the collision occurs soon after the host vehicle begins to accelerate, shortening the time between the host vehicle starting and the collision between the host vehicle VM and the target object TG. Therefore, there is insufficient time series data to accurately calculate the average value CAm and standard deviation σ of multiple collision areas CA, reducing the accuracy of calculating the distributed collision area CAd.

Furthermore, when the host vehicle starts moving after stopping, acceleration is high and the host vehicle's speed often increases rapidly. For this reason, the average value CAm of the multiple collision areas CA is likely to change, and the standard deviation σ is likely to increase. Therefore, the collision area CAd, which has a distribution that is the range obtained by adding ±3σ to the average value CAm of the multiple collision areas CA, fluctuates significantly over time, as shown in FIG. 18 . Furthermore, fluctuations in the average value CAm of the multiple collision areas CA lag behind fluctuations in the collision area CA. For this reason, if a braking operation for the host vehicle is performed when the collision area CAd having the distribution is within the braking-enabled area BA, and the braking operation for the host vehicle is not performed when the collision area CAd is only included in the braking-free area NBA (when not within the braking-enabled area BA), there is a risk that a braking operation will be performed unnecessarily. Furthermore, even if the target TG stops before colliding with the host vehicle VM, a braking operation may be performed unnecessarily due to the response delay of the collision area CAd.

Therefore, when the host vehicle starts moving after stopping, if the collision area CA (second collision area) is included only in the no-braking area NBA, the braking determination unit 250 disables braking of the host vehicle by the braking device 310. On the other hand, if the collision area CA is not included only in the no-braking area NBA, i.e., if it is included only in the braking-enabled area BA, or if it is included in both the braking-enabled area BA and the no-braking area NBA, the braking determination unit 250 performs braking of the host vehicle by the braking device 310.

Furthermore, as shown in FIG. 18 , when the host vehicle starts moving after stopping, the collision range is likely to shift toward the rear end of the host vehicle. In this case, if the braking range BA is set wide from the front end to the rear end of the host vehicle VM, the collision range may enter the braking range BA, causing the host vehicle VM to brake, making it more likely that the host vehicle VM will collide with the target TG. For this reason, the braking range BA (hereinafter referred to as the "second braking range BA2") when the host vehicle starts moving after stopping is set narrower in the fore-and-aft direction than the braking range BA (hereinafter referred to as the "first braking range BA1") when the host vehicle is normally traveling. Specifically, the range of the second braking range BA2 set from the front end to the rear end of the host vehicle VM when the host vehicle starts moving after stopping is set narrower than the range of the first braking range BA1 set from the front end to the rear end of the host vehicle VM when the host vehicle VM is normally traveling. That is, with regard to the no-braking area NBA set at the rear of the host vehicle existence area EA1 (host vehicle VM), the no-braking area NBA when the host vehicle starts moving after stopping (hereinafter referred to as the "second no-braking area NBA2") is set wider than the no-braking area NBA when the host vehicle VM is normally driving (hereinafter referred to as the "first no-braking area NBA1").

The collision determination and braking control by the brake control ECU 200 described above is performed according to the procedure shown in Figure 19. Note that this processing continues after the brake control ECU 200 is instructed to execute the processing until it is instructed to end the processing.

In step S110, the object detection device 110 detects a target TG ahead. In step S120, the vehicle movement calculation unit 210 calculates a vehicle solid D1 in a three-dimensional coordinate system defined based on the current position of the vehicle VM, which indicates the movement of the vehicle existence area EA1 on the vehicle's estimated path PA1 from the present until a certain time has elapsed (see FIGS. 2 and 4). Also in step S120, the target movement calculation unit 220 calculates a target solid D2 in the three-dimensional coordinate system, which indicates the movement of the target existence area EA2 on the target's estimated path PA2, which is calculated from the position of the target TG output from the object detection device 110 and the relative speed of the target TG with respect to the vehicle VM (see FIGS. 3 and 4). Note that specific procedures for calculating the vehicle solid D1 and the target solid D2 may be, for example, those described in JP 2020-8288 A.

In step S130, the collision determination unit 230 determines whether the target TG will collide with the host vehicle VM, based on whether or not there is an intersection between the host vehicle solid D1 and the target solid D2 calculated in step S120. Specifically, as described using FIG. 5, if there is an overlapping area CPA between the first determination area DA1 and the second determination area DA2 at the same elapsed time T, it is determined that there is an intersection between the host vehicle solid D1 and the target solid D2, and it is determined that the target TG will collide with the host vehicle VM. If it is determined that the target TG will collide with the host vehicle VM, proceed to step S140. If it is determined that there is no intersection between the host vehicle solid D1 and the target solid D2, and the target TG will not collide with the host vehicle VM, the process returns to step S110.

In step S140, the collision range calculation unit 240 calculates the positions of the host vehicle VM and the target TG at the collision timing Ta, specifically the positions of the host vehicle existence area EA1 and the target existence area EA2 (see Figure 7), and in step S150, the collision range calculation unit 240 calculates the collision range CA of the host vehicle (see Figures 7 to 11).

In step S160, the host vehicle stop-start determination unit 245 (start determination unit) determines whether the host vehicle VM is starting after a stop. Specifically, the host vehicle stop-start determination unit 245 determines that the host vehicle VM is starting after a stop based on the following conditions: the speed of the host vehicle VM has increased from a state below 0 to a state above 0, the elapsed time since the speed of the host vehicle VM increased above 0 is shorter than a predetermined time, the speed of the host vehicle VM is lower than a predetermined speed above 0, and a target TG is approaching the host vehicle VM. On the other hand, the host vehicle stop-start determination unit 245 determines that the host vehicle VM is not starting after a stop if at least one of the above condition elements is not met. If it is determined that the host vehicle VM is not starting after a stop, the process proceeds to step S164; if it is determined that the host vehicle VM is starting after a stop, the process proceeds to step S162.

In step S164, the collision area calculation unit 240 calculates the average value CAm and standard deviation σ of a certain number (plurality) of accumulated collision areas CA. Specifically, the average value CAlm and standard deviation σl of the left edge position CA1 of the collision area CA, and the average value CArm and standard deviation σr of the right edge position CAr are calculated.

In step S166, the braking determination unit 250 determines whether the collision range CAd, calculated by adding the standard deviation σ to the average value CAm, is included only in the first braking-free range NBA1. The collision range CAd is a range having a distribution calculated from the average value CAm and the standard deviation σ, for example, a range obtained by adding a distribution of ±3σ to the average value CAm of the collision range CA. Specifically, as shown in FIG. 13, the collision range CAd is the distance between the left end position (CAlm-3σl), which is expanded outward by the distribution 3σl from the average value CAlm of the left end position CAl, and the right end position (CArm+3σr), which is expanded outward by the distribution 3σr from the average value CArm of the right end position CAr.

If the collision area CAd is included only in the first braking-free area NBA1, braking of the host vehicle by the braking device 310 is deactivated, and processing returns to step S110. On the other hand, if the collision area CAd is not included only in the first braking-free area NBA1, i.e., if it is included only in the first braking-enabled area BA1, or if it is included in both the first braking-enabled area BA1 and the first braking-free area NBA1, braking of the host vehicle by the braking device 310 is performed in step S170. In this way, if it is determined that the host vehicle VM is not starting after a stop, and the collision area CAd is included in the first braking-enabled area BA1, it is determined that braking of the host vehicle VM will be performed.

Meanwhile, in step S162, the braking determination unit 250 determines whether the collision area CA is included only in the second braking-free area NBA2. If the collision area CA is included only in the second braking-free area NBA2, braking of the host vehicle by the braking device 310 is deactivated, and processing returns to step S110. On the other hand, if the collision area CA is not included only in the second braking-free area NBA2, that is, if it is included only in the second braking-enabled area BA2, or if it is included in both the second braking-enabled area BA2 and the second braking-free area NBA2, braking of the host vehicle by the braking device 310 is performed in step S170. In this way, if it is determined that the host vehicle VM is starting after a stop, and the collision area CA is within the second braking-enabled area BA2, it is determined that braking of the host vehicle VM will be performed.

Then, the process returns to step S110 and repeats the process in Figure 19 until an instruction to end the process is received, and if an instruction to end the process is received, the process in Figure 19 ends.

The present embodiment described above has the following advantages:

The host vehicle stop-start determination unit 245 determines whether the host vehicle VM is starting after a stop. If the host vehicle stop-start determination unit 245 determines that the host vehicle VM is not starting after a stop, the braking determination unit 250 determines whether to execute a braking operation for the host vehicle VM based on the positional relationship between the collision area CAd calculated based on the average value CAm and standard deviation σ of the multiple collision areas CA calculated by the collision area calculation unit 240 and the first braking area BA1 set for the host vehicle VM. Therefore, if it is determined that the host vehicle VM is not starting after a stop and sufficient time series data is available to calculate the average value CAm and standard deviation σ of the multiple collision areas CA, the prediction accuracy of the collision area CAd can be improved. Then, it is possible to appropriately determine whether to execute a braking operation for the host vehicle VM based on the positional relationship between the collision area CAd and the first braking area BA1 set for the host vehicle VM.

- When the host vehicle stop-start determination unit 245 determines that the host vehicle VM is starting after a stop, the braking determination unit 250 determines whether to execute a braking operation for the host vehicle VM based on the positional relationship between the collision area CA currently calculated by the collision area calculation unit 240 and the second braking area BA2. Therefore, when the host vehicle VM is determined to be starting after a stop and sufficient time series data is not available to calculate the average value CAm and standard deviation σ of multiple collision areas CA, the currently calculated collision area CA can be used without using the collision area CAd. Therefore, it is possible to prevent a decrease in the prediction accuracy of the collision area in the event of a head-on collision after the host vehicle has stopped. Then, it is possible to appropriately determine whether to execute a braking operation for the host vehicle VM based on the positional relationship between the collision area CA and the second braking area BA2.

- When the host vehicle stop-start determination unit 245 determines that the host vehicle is not starting after a stop, the braking determination unit 250 sets the first brakeable range BA1 as the brakeable range BA, and when the host vehicle stop-start determination unit 245 determines that the host vehicle is starting after a stop, the braking determination unit 250 sets the second brakeable range BA2, which is different from the first brakeable range BA1, as the brakeable range BA. With this configuration, when it is determined that the host vehicle is starting after a stop, it can appropriately determine whether to perform a braking operation on the host vehicle VM based on the second brakeable range BA2, which is different from the first brakeable range BA1 when it is determined that the host vehicle is not starting after a stop.

- The range of the second braking range BA2 set from the front end to the rear end of the host vehicle VM is narrower than the range of the first braking range BA1 set from the front end to the rear end of the host vehicle VM. Therefore, when it is determined that the host vehicle VM is starting after stopping, the second braking range BA2, which is set from the front end to the rear end of the host vehicle VM and is narrower than the first braking range BA1, can be set for the host vehicle VM. Therefore, in the event of a head-on collision after the host vehicle has stopped, it is possible to prevent unnecessary braking operations of the host vehicle VM from being performed.

The host vehicle stop-start determination unit 245 determines that the host vehicle VM is starting after a stop when the host vehicle VM's speed increases from a state below 0 to a state above 0, the time elapsed since the host vehicle VM's speed increased above 0 is shorter than a predetermined time, the speed of the host vehicle VM is lower than a predetermined speed higher than 0, and an object is approaching the host vehicle VM. With this configuration, if the time elapsed since the host vehicle VM's speed increased above 0 is longer than a predetermined time, it can be determined that the host vehicle VM is not starting after a stop. Furthermore, if the speed of the host vehicle VM increases above a predetermined speed higher than 0, it can be determined that the host vehicle VM is not starting after a stop. Furthermore, if no object is approaching the host vehicle VM, it can be determined that the host vehicle VM is not starting after a stop. Therefore, it is possible to appropriately determine that the host vehicle VM is starting after a stop, i.e., a situation in which a head-on collision may occur after the host vehicle stops.

The above embodiment can also be modified as follows. The same parts as those in the above embodiment are designated by the same reference numerals and will not be described again.

- When the host vehicle stop-start determination unit 245 determines whether the host vehicle VM is starting after a stop, some of the above condition elements may be omitted or new condition elements may be added. For example, a condition element may be added that the time elapsed since it was determined that the host vehicle VM is starting after a stop has not exceeded a predetermined time. Also, a condition element may be added that the acceleration of the host vehicle VM is greater than a predetermined acceleration.

- The braking determination unit 250 may determine to perform a braking operation on the host vehicle VM when it is determined that the host vehicle VM is not starting after a stop and the collision area CAd is only within the first braking area BA1. The braking determination unit 250 may also determine to perform a braking operation on the host vehicle VM when it is determined that the host vehicle VM is starting after a stop and the collision area CAd is only within the second braking area BA2.

The braking determination unit 250 may also determine to perform a braking operation on the host vehicle VM when it is determined that the host vehicle VM is not starting after stopping and the collision area CA is within the first braking area BA1. In other words, when it is determined that the host vehicle VM is not starting after stopping, the braking determination unit 250 may also determine to perform a braking operation on the host vehicle VM when the collision area CAd or the collision area CA is within the first braking area BA1.

- The braking determination unit 250 may determine to perform a braking operation on the host vehicle VM when it is determined that the host vehicle VM is starting after stopping and the collision range CA is within the first braking range BA1. In other words, the braking range BA may be the same and the collision range may be different when it is determined that the host vehicle VM is starting after stopping and when it is determined that the host vehicle VM is not starting after stopping.

- The braking determination unit 250 may determine to perform a braking operation on the host vehicle VM when it is determined that the host vehicle VM is starting after stopping and the collision range CAd is within the second braking range BA2. In other words, the collision range may be the same and the braking range BA may be different when it is determined that the host vehicle VM is starting after stopping and when it is determined that the host vehicle VM is not starting after stopping.

- In the above embodiment, the object detection device 110 is a device composed of a millimeter-wave radar sensor 111 and a radar ECU 112, but this is not limited to this and the device may also be equipped with an image sensor that detects the position of a target using a captured image, or a laser sensor that detects the position of a target using laser light. Furthermore, if the host vehicle is capable of performing vehicle-to-vehicle communication with another vehicle traveling around the host vehicle, the host vehicle may acquire the position of an object detected by an object detection device equipped in the other vehicle through vehicle-to-vehicle communication. Furthermore, the device may also be a combination of these various devices.

- In the above embodiment, a vehicle was used as an example of the target TG, but this is not limited to this and the target may be any object that has the potential to collide with the host vehicle, such as a vehicle, bicycle, motorcycle, pedestrian, animal, or structure.

- In the above embodiment, the target presence area EA2 of the target TG is set as a rectangular area that includes the entire periphery of the target when the target TG is viewed from above, but this is not limited to this and may be any polygon that is set to include the entire periphery of the target.

- In the above embodiment, the positional relationship between the collision area CA and the braking-free area NBA is determined using a one-dimensional coordinate system converted from a two-dimensional coordinate system, but this is not limited to this and the determination may also be made using a two-dimensional coordinate system. Using a two-dimensional coordinate system will complicate the processing, but it is possible to determine the positional relationship between the collision areas CA, CAd and the braking-free area NBA in a similar manner.

- In the above embodiment, the presence or absence of a collision is determined based on whether or not the subject vehicle solid D1 and the target solid D2, which have an extension in a three-dimensional coordinate system, intersect. However, this is not limited to this, and the presence or absence of a collision may also be determined based on whether or not the subject vehicle's linear estimated vehicle path PA1 intersects with the target's linear estimated target path PA2 in a two-dimensional coordinate system. Even in this case, the accuracy of collision determination will be lower than in the embodiment, but it is still possible to determine whether or not a collision has occurred.

- In the above embodiment, the collision area CA is used as the collision position, and whether or not to brake the vehicle is controlled depending on the positional relationship between the collision area CA and the no-braking area NBA. However, this is not limited to this, and the collision point CP may be used as the collision position, and whether or not to brake the vehicle may be controlled depending on the positional relationship between the collision point CP and the no-braking area NBA. In other words, the collision area CA may be composed only of the collision point CP.

In the above embodiments, the braking control device is described as being configured by a computer including a CPU, ROM, RAM, input/output interfaces, etc., and each function is realized in software by the CPU executing an application corresponding to each function, using the braking control ECU 200 as an example. However, this is not limited to this, and the device may be realized in hardware using discrete circuits or integrated circuits. That is, the control device and its method in each of the above embodiments may be realized by a dedicated computer provided by configuring a processor and memory programmed to execute one or more functions embodied in a computer program. Alternatively, the control unit and its method described in this disclosure may be realized by a dedicated computer provided by configuring a processor with one or more dedicated hardware logic circuits. Alternatively, the control unit and its method described in this disclosure may be realized by one or more dedicated computers configured by combining a processor and memory programmed to execute one or more functions with a processor configured with one or more hardware logic circuits. Furthermore, the computer program may be stored as instructions executed by a computer on a computer-readable non-transitory tangible storage medium.

The present disclosure has been described above based on embodiments and modifications. However, the above-described embodiments of the invention are intended to facilitate understanding of the present disclosure and are not intended to limit the present disclosure. The present disclosure may be modified or improved without departing from the spirit and scope of the claims, and equivalents thereof are included in the present disclosure. For example, the technical features in the embodiments and modifications corresponding to the technical features in each aspect described in the Summary of the Invention section may be replaced or combined as appropriate to solve some or all of the above-mentioned problems or to achieve some or all of the above-mentioned effects. Furthermore, if a technical feature is not described as essential in this specification, it may be deleted as appropriate.

200... Braking control ECU (brake control device), 240... Collision range calculation unit, 245... Host vehicle stop and start determination unit (start determination unit), 250... Braking determination unit (execution determination unit), TG... target (object), VM... host vehicle.

Claims (5)

A braking control device (200) for controlling a braking operation of a host vehicle (VM),
a collision range calculation unit (240) that calculates a collision range (CA, CAd) of the host vehicle at a timing of collision between the host vehicle and an object (TG);
a start determination unit (245) that determines whether the vehicle is starting after stopping;
an execution determination unit (250) that, when it is determined by the start determination unit that the vehicle is not starting after stopping, determines whether or not to execute a braking operation for the vehicle based on a positional relationship between a first collision range (CAd) calculated based on an average value and a standard deviation of the plurality of collision ranges (CA) calculated by the collision range calculation unit and a braking range (BA1, BA2) set for the vehicle, and, when it is determined by the start determination unit that the vehicle is starting after stopping, determines whether or not to execute a braking operation for the vehicle based on a positional relationship between a second collision range (CA), which is the collision range currently calculated by the collision range calculation unit, and the braking range;
Equipped with
the braking possible range is a region of the host vehicle existence region in which the host vehicle exists, excluding a predetermined no-braking range,
The braking control device , wherein the no-braking range is an area corresponding to a trunk position at the rear of the vehicle . The braking control device according to claim 1, wherein the execution determination unit sets the braking range to a first braking range (BA1) when the start determination unit determines that the vehicle is not starting after stopping, and sets the braking range to a second braking range (BA2) different from the first braking range when the start determination unit determines that the vehicle is starting after stopping. The brake control device according to claim 2, wherein the execution determination unit determines to execute a braking operation for the host vehicle when the start determination unit determines that the host vehicle is not starting after stopping and the first collision range is within the first braking range, and determines to execute a braking operation for the host vehicle when the start determination unit determines that the host vehicle is starting after stopping and the second collision range is within the second braking range. The braking control device according to claim 3, wherein the range in which the second braking range is set in the direction from the front end to the rear end of the host vehicle is narrower than the range in which the first braking range is set in the direction from the front end to the rear end of the host vehicle. A braking control device according to any one of claims 1 to 4, wherein the start determination unit determines that the host vehicle is starting after a stop when the host vehicle's speed has changed from a state below 0 to a state above 0, the time elapsed since the host vehicle's speed became above 0 is shorter than a predetermined time, the host vehicle's speed is lower than a predetermined speed above 0, and an object is approaching the host vehicle.