JP5939456B2 - Collision damage reduction device - Google Patents

Description

  The present invention relates to a collision damage reducing device for a vehicle.

  In the collision damage alleviating apparatus described in Japanese Patent Laid-Open No. 2009-101756, a distance L between a vehicle and an obstacle located in the vehicle traveling direction and a relative speed V between the vehicle and the obstacle are measured by an inter-vehicle distance radar. The collision time t (t = L / V) until the collision with the obstacle is calculated. When the collision time t becomes a predetermined value or less, the vehicle brake is forcibly operated.

JP 2009-101756 A

  In the apparatus described in Patent Document 1, an object having a low possibility of collision with a vehicle, such as a structure existing at a place off a road that curves forward and a parked vehicle, is detected as an obstacle. Even in this case, forcible braking is applied to the vehicle when the collision time between the vehicle and the obstacle reaches the determination threshold value (predetermined value). For this reason, there is a possibility that a deceleration that is useless for the traveling of the vehicle occurs and the driver feels uncomfortable.

  Such inconvenience can be avoided by setting the collision time determination threshold to a short value. However, if the collision time determination threshold is set to a short value, the vehicle will not sufficiently decelerate by the time of the collision, reducing the desired collision damage. There is a possibility that the effect cannot be obtained.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a collision damage reducing device that can suppress unnecessary braking and a sense of incongruity for a driver and obtain a desired collision damage reducing effect.

In order to achieve the above object, a collision damage alleviating apparatus for a vehicle according to the present invention includes an imaging unit, a traveling path determination unit, an object detection unit, a pre-collision state determination unit, and a braking control unit. The imaging means images the traveling road ahead of the traveling direction of the vehicle and outputs the image information. The traveling path determination means is image information output by the imaging means to determine whether or not the traveling path has a characteristic that can be estimated to be an obstacle that is highly likely to collide with an object located far away from the vehicle. Determine based on. The object detection means detects a relative distance and a relative speed between an object existing in front of the traveling direction of the vehicle and the vehicle. When the traveling path determination means determines that the pre-collision state determination means has the above characteristics, the first possibility that a collision between the object and the vehicle is high is based on the relative distance and the relative speed detected by the object detection means. If the traveling path determination means determines that the characteristic does not have the above-described state, the object and the vehicle are detected based on the relative distance and the relative speed detected by the object detection means. It is determined whether or not the second pre-collision state is higher than the first pre-collision state. The braking control means is a case where the traveling road determination means determines that the braking characteristic has the above-described characteristics, and if the first pre-collision state that occurs earlier than the second pre-collision state is determined. When the means determines, the first braking force is generated in the braking means for generating the braking force for the vehicle, and the travel path determination means determines that the above characteristic is not present, and before the second collision occurs. When the pre-collision state determination unit determines that the state is the state, the braking unit generates a second braking force that is greater than the first braking force.

  In the above configuration, when the vehicle is traveling on a traveling road having characteristics that can be estimated to be an obstacle that is highly likely to collide with an object that is located far from the vehicle, and the traveling road has the above characteristics. When the travel path determination means determines, the pre-collision state determination means determines whether or not there is a first pre-collision state where there is a high possibility of a collision between the object and the vehicle. When it is determined that there is, the braking control means generates a braking force for the vehicle. In addition, when the vehicle is traveling on a traveling road that does not have the above characteristics and the traveling road determination means determines that the traveling road does not have the above characteristics, the state determination means before the occurrence of a collision It is determined whether or not the vehicle is in the front state, and when it is determined that the vehicle is in the state before the second collision occurrence, the braking control unit generates a braking force on the vehicle.

  In the second pre-collision state, the possibility of a collision between the object and the vehicle is set to be higher than that in the first pre-collision state, so the first pre-collision state is the second pre-collision state. It occurs earlier than the state before the collision. For this reason, when it is determined that the traveling road has the above characteristics, the braking force is generated earlier than when it is determined that the driving path does not have the above characteristics, and the vehicle is sufficiently decelerated by the time of the collision. It is possible to obtain a desired collision damage reduction effect. In addition, when it is determined that the travel path has the above characteristics, the distant object detected by the object detection unit is estimated to be an obstacle that has a high possibility of colliding with the vehicle. The possibility of being wasted for vehicle travel is low. In addition, since the driver recognizes the object as an obstacle having a high possibility of collision with the vehicle, even if the braking force is generated early, the uncomfortable feeling given to the driver is suppressed. Accordingly, it is possible to suppress unnecessary braking and a sense of incongruity for the driver and to obtain a desired collision damage reduction effect.

The travel path determination means calculates the number of predetermined feature points of the travel path, the lane width of the travel path, and the curvature of the travel path based on the image information output by the imaging means, The number of feature points is less than or equal to a predetermined quantity, the difference between the lane width of the travel path and a preset vehicle width is greater than or equal to a predetermined length, and the curvature of the travel path is less than or equal to a predetermined curvature. in some cases, the traveling path, to determine the object existing in the distance of the vehicle to be likely obstacle colliding with the vehicle and having an estimable characteristics rather good also, the predetermined feature point An indication on the road surface of the traveling road may be included .

  In the above configuration, the predetermined feature point of the travel path indicates, for example, a parked vehicle on the roadside or a display of a pedestrian crossing drawn on the road surface. In many cases, roads that are equivalent to automobile roads such as expressways and roads that are substantially straight and have a substantially straight line have the number of feature points below a predetermined number, and the lane width of the road and the vehicle Since the difference from the vehicle width is equal to or greater than a predetermined length and the curvature of the travel path is equal to or less than the predetermined curvature, it is determined that the travel path has the above characteristics. On such a road, the vehicle is likely to be traveling at high speed, but since a forced braking force is generated early, a desired collision damage reduction effect can be obtained.

  On the other hand, in the case of a general road having many feature points, a road with a narrow lane width, or a road that bends, it is determined that the above characteristic is not present. Therefore, although the forced braking force is generated when it is determined that the state before the second collision occurs, the driver usually has high attention to the front of the vehicle on such a road, and the vehicle speed. Therefore, the desired collision damage reduction effect can be obtained without generating a forcible braking force at an early stage.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to suppress a useless braking and the uncomfortable feeling with respect to a driver | operator, and to obtain the desired collision damage reduction effect.

It is a block diagram which shows the principal part of the vehicle provided with the collision damage reduction apparatus concerning embodiment of this invention. It is a flowchart which shows a collision damage reduction process. It is a flowchart which shows a travel path characteristic determination process. It is a figure explaining extraction of the feature point from image information.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 1, a vehicle 1 according to this embodiment includes a camera (imaging means) 2, an inter-vehicle distance sensor (object detection means) 3, an ECU 4, an alarm device 5, and a brake actuator (braking means) 6. And.

  The camera 2 is a CCD camera or the like, and continuously captures the travel path ahead of the vehicle 1 and the periphery of the travel path, and outputs image information to the ECU 4.

  The inter-vehicle distance sensor 3 transmits an electromagnetic wave such as a laser or a millimeter wave every predetermined time from a front end portion of the vehicle 1 within a range of a predetermined angle forward in the traveling direction, and receives the reflected wave, thereby Detect objects inside. Further, the relative distance L (m) and the relative speed Vr (m / s) between the detected object and the vehicle 1 are detected and output to the ECU 4.

  The ECU 4 includes a CPU (Central Processing Unit), an image processor, a ROM (Read Only Memory), and a RAM (Random Access Memory). The CPU reads the collision damage mitigation processing program stored in the ROM and executes the collision damage mitigation process, so that the travel path characteristic determination unit 10, the collision time calculation unit 11, the braking timing adjustment unit 12, and the braking control unit 13 are obtained. Function. The RAM stores a storage area for the relative distance L and the relative speed Vr detected by the inter-vehicle distance sensor 3, a temporary storage area for a CPU calculation result, a determination threshold value for a collision time, which will be described later, various determination reference values for determination of road characteristics, and a characteristic flag. Functions as a setting area. The image processor processes the image information output from the camera 2 and extracts a white line on the travel path.

  The alarm device 5 is provided, for example, in an instrument panel (not shown) in the passenger compartment, and generates a buzzer sound or the like to alert the driver when receiving a notification instruction signal from the ECU 4.

  When the brake actuator 6 receives a control signal from the ECU 4, the brake actuator 6 forcibly activates disc brakes of front wheels and rear wheels (not shown) to generate a predetermined braking force on each wheel.

  The travel path characteristic determination unit 10 extracts the white line of the travel path from the image information output by the camera 2, the lane width of the travel path, the curvature of the travel path, and the number of feature points in a predetermined area in front of the vehicle, Is calculated. By comparing the calculated lane width, curvature, and quantity of feature points with predetermined determination reference values, the road is an obstacle that is highly likely to collide with an object that exists far away from the vehicle 1. It is determined whether there is a characteristic that can be estimated (hereinafter referred to as an obstacle estimable characteristic), and the determination result is output to the braking timing adjustment unit 12. That is, the travel path characteristic determination unit 10 constitutes a travel path determination unit that determines whether the travel path has an obstacle estimable characteristic based on the image information from the camera 2.

  The collision time calculation unit 11 calculates a collision time (TTC: Time to collision) (s) from the relative distance L and the relative speed Vr detected by the inter-vehicle distance sensor 3 until the object and the vehicle 1 are predicted to collide. The calculated value is output to the braking timing adjustment unit 12.

  The braking timing adjustment unit 12 acquires a determination result from the traveling road characteristic determination unit 10 and acquires a TTC from the collision time calculation unit 11. When the traveling road has an obstacle estimable characteristic, the TTC is compared with a preset determination threshold value T1 to determine whether or not the first state before the occurrence of the collision, and the determination result is sent to the braking control unit 13. Output. When the travel path does not have an obstacle estimable characteristic, the TTC is compared with a preset determination threshold T2 to determine whether or not the second pre-collision state is present, and the determination result is brake controlled. To the unit 13. That is, the braking timing adjustment unit 12 and the collision time calculation unit 11 constitute a pre-collision state determination unit. The determination threshold values T1 and T2 are set in advance, respectively. The determination threshold value T2 is set to a minimum time (for example, 0.8 seconds) necessary for reducing collision damage, for example, whereas the determination threshold value T1 is , A time longer than the determination threshold T2 (for example, 3 seconds) is set.

  When the determination result of the braking timing adjustment unit 12 is the state before the occurrence of the first collision, the braking control unit 13 operates the brake actuator 6 to apply the first braking force to the vehicle 1. Further, when the determination result of the braking timing adjustment unit 12 is the state before the second collision occurrence, the brake actuator 6 is operated to apply the second braking force to the vehicle 1. That is, the braking control unit 13 constitutes a braking control unit that generates a braking force for the vehicle 1 according to the determination result of the braking timing adjustment unit 12. The second braking force is set such that a braking force larger than the first braking force (for example, the maximum braking force that can be generated by the brake actuator 6) is applied.

  Next, the collision damage reduction processing executed by the ECU 4 will be described based on the flowchart of FIG. This process is executed every predetermined time. First, the ECU 4 acquires the relative distance L and the relative speed Vr (step S1). Next, TTC is calculated by substituting the relative distance L and the relative speed Vr into the equation (1) (step S2).

    TTC = L / Vr (1)

  Next, the ECU 4 executes a travel path characteristic determination process (step S3). In the travel path characteristic determination process, as shown in the flowchart of FIG. 3, the ECU 4 acquires image information from the camera 2 (step S21). The image information acquired by the ECU 4 is processed by the image processing processor of the ECU 4. The image processor performs noise removal, edge extraction and binarization from the image information, extracts straight lines and curve components by Hough transform, etc., and corresponds to a lane as shown in FIG. 4 from the extracted straight lines and curve components A white line (thick line shown in FIG. 4) is extracted (step S22). For example, the ECU 4 calculates the distance in the horizontal direction perpendicular to the left and right white lines corresponding to the lane, and calculates the lane width of the travel path (step S23). Next, the ECU 4 calculates the curvature of the white line corresponding to the lane by, for example, fitting by a least square method of a polynomial representing a curve, and calculates the curvature of the traveling road (step S24). Next, the ECU 4 calculates the quantity of feature points (step S25). Specifically, as shown in FIG. 4, a search area (a region surrounded by a dotted line shown in FIG. 4) in the travel lane and adjacent portion of the vehicle 1 with reference to a white line corresponding to a lane in the image information. To search for feature points in the search area. Characteristic points include characters and symbols displayed on the road surface such as a pedestrian crossing, speed, and destination, a parked vehicle, a vehicle in front, a vehicle in an adjacent lane, and the like. The number of feature points is calculated by, for example, extracting feature points having a concentration gradient (circle points shown in FIG. 4) from the search area, and calculating the movement amount of the feature points by optical flow, which is a temporal change in the concentration gradient. (Arrows shown in FIG. 4), and the number of feature points (search shown in FIG. 4) is determined by identifying and quantifying the moving feature points by storing temporal changes of the feature points according to the vehicle speed of the vehicle 1. Calculate the number of round dots in the area.

  Next, the ECU 4 determines whether or not the number of extracted feature points is equal to or smaller than a predetermined number set in advance (step S26), and the difference between the lane width of the travel path and the vehicle width of the vehicle 1 is equal to or larger than a predetermined length. Whether or not (step S27) and whether or not the curvature of the traveling path is equal to or less than a predetermined curvature (step S28) are determined. When all the above three determination conditions are satisfied (when each step is YES), the characteristic flag is turned on (step S29) and the process is terminated. If even one of the three determination conditions is not satisfied (one of each step is NO), the characteristic flag is turned off (step S30) and the process is terminated.

  Next, the ECU 4 determines whether or not the characteristic flag is on (step S4). If the characteristic flag is off (step S4: NO), the ECU 4 proceeds to step S8. If the characteristic flag is on (step S4: YES), the traveling road has an obstacle estimable characteristic, so the TTC calculated in step S2 is compared with the determination threshold T1 (step S5). When TTC is equal to or less than T1 (step S5: YES), it is determined that the state is before the first collision occurrence, and a warning instruction signal is output to the alarm device 5 to alert the driver (step S6). A control signal is output to the actuator 6 to generate a first braking force (step S7). When TTC exceeds T1 (step S5: NO), the process is terminated without generating the first braking force. When the process proceeds to step S8, since the traveling road does not have the obstacle estimable characteristic, the TTC is compared with the determination threshold value T2. When TTC is equal to or less than T2 (step S8: YES), it is determined that the state is before the second collision occurrence, and a control signal is output to the brake actuator 6 to generate a second braking force (step S9). When TTC exceeds T2 (step S8: NO), the process is terminated without generating the second braking force.

  In the present embodiment, when the traveling road characteristic determining unit 10 determines that the traveling road has an obstacle estimable characteristic, the braking timing adjusting unit 12 compares the TTC with the determination threshold T1 before the first collision occurs. The brake control unit 13 causes the vehicle 1 to generate a first braking force when it is determined whether or not the vehicle is in a state, and when it is determined that the state is the state before the first collision. In addition, when the travel path characteristic determination unit 10 determines that the travel path does not have an obstacle estimable characteristic, the braking timing adjustment unit 12 compares the TTC and the determination threshold value T2 to determine the second pre-collision state. The braking control unit 13 causes the vehicle 1 to generate a second braking force when it is determined whether or not the vehicle is in the state before the occurrence of the second collision. Since the determination threshold T1 is set to be longer than the determination threshold T2, the first pre-collision state occurs earlier than the second pre-collision state. For this reason, when it is determined that the traveling road has the obstacle estimable characteristic, the braking force is generated earlier than the case where it is determined that the road has no obstacle estimable characteristic. 1 can be sufficiently decelerated to obtain a desired collision damage alleviating effect. Further, when it is determined that the travel path has an obstacle estimable characteristic, it is estimated that a distant object detected by the inter-vehicle distance sensor 3 is an obstacle that is highly likely to collide with the vehicle 1. It is unlikely that the first braking force that has been caused is wasted for the travel of the vehicle 1. In addition, since the driver recognizes the object as an obstacle having a high possibility of collision with the vehicle 1, even if the braking force is generated early, the uncomfortable feeling given to the driver is suppressed. Accordingly, it is possible to suppress unnecessary braking and a sense of incongruity for the driver and to obtain a desired collision damage reduction effect.

  Further, the travel path characteristic determination unit 10 has the number of feature points of the travel path equal to or less than a predetermined quantity, the difference between the lane width of the travel path and the vehicle width of the vehicle 1 is equal to or greater than a predetermined length, and the travel path. It is determined that the traveling road has an obstacle estimable characteristic. An automobile-only road such as an expressway or a road equivalent to an automobile-only road, and a substantially straight traveling road, in many cases, the number of feature points is equal to or less than a predetermined quantity, and the lane width of the traveling road and the vehicle 1 Since the difference from the vehicle width is equal to or greater than a predetermined length and the curvature of the travel path is equal to or less than the predetermined curvature, it is determined that the travel path has an obstacle estimable characteristic. In such a travel path, the vehicle 1 is likely to be traveling at high speed and the number of feature points is small, which may reduce the driver's attention to the front of the vehicle. Since power is generated at an early stage, the vehicle 1 can be sufficiently decelerated by the time of a collision to obtain a desired collision damage reduction effect.

  On the other hand, in the case of a general road having many feature points, a road with a narrow lane width, or a road that bends, it is determined that it does not have an obstacle estimable characteristic. Accordingly, the second braking force is generated when it is determined that the second pre-collision state has occurred. However, on such a road, the driver usually has high attention to the front of the vehicle and the vehicle speed is low. Therefore, it is possible to obtain a desired collision damage reduction effect without generating a forced braking force at an early stage.

In the present embodiment, the first and second pre-collision state is determined based on the TTC. However, the determination of the first and second pre-collision state is not limited to the determination based on the TTC, Other determinations may be made. For example, the determination may be made based on the distance D (m) necessary to give the vehicle 1 the deceleration α (m / s ² ) and make the relative speed Vr zero. The distance D can be obtained by substituting the relative speed Vr and the deceleration rate α into the equation (2).

D = Vr ² / 2α (2)

  In this case, for example, as the determination threshold value for the first pre-collision state, the distance D1 necessary for setting the relative speed Vr to zero when the deceleration α1 is applied to the vehicle 1 is set in advance. The distance D2 necessary for setting the relative speed Vr to zero when the deceleration α2 is applied to the vehicle 1 is set in advance as the determination threshold value for the pre-collision state. The braking control unit 13 generates a braking force corresponding to the deceleration α1 when determined to be the first pre-collision state, and corresponds to the deceleration α2 when determined to be the second pre-collision state. Generate braking force. By setting the deceleration α1 to a value smaller than the deceleration α2 (for example, the maximum deceleration of the vehicle 1), the determination threshold D1 is longer than the determination threshold D2. Accordingly, the first pre-collision state occurs earlier than the second pre-collision state, and the first braking force also occurs early, so that the vehicle 1 is sufficiently decelerated by the time of the collision and is desired. It is possible to obtain a collision damage reduction effect.

  In addition, the application of the braking force to the vehicle 1 when determined to be the state before the occurrence of the collision is not limited to the present embodiment. For example, whether the state is the second state before the occurrence of the collision after the application of the first braking force. When the second pre-collision state is determined, a second braking force may be further applied to the vehicle 1. Moreover, the magnitude | size of the 1st braking force and 2nd braking force to set is arbitrary, and is not limited to this embodiment.

  In addition, the travel path characteristic determination unit 10 calculates three determination elements, which are the number of feature points, the lane width of the travel path, and the curvature of the travel path, and the travel path is obstructed when each satisfies a predetermined determination condition. Although it has been determined that the object has estimable characteristics, other determinations may be used. For example, when one element such as the curvature of the traveling road among the above three determination elements satisfies the determination condition, it may be determined that the traveling road has an obstacle estimable characteristic. Alternatively, the calculated three determination elements may be multiplied by predetermined weighting factors, respectively, and it may be determined whether or not the traveling road has an obstacle estimable characteristic based on the level of the calculation result. In addition, the determination by the travel path characteristic determination unit 10 is not limited to the determination by the above three determination elements. For example, the travel path characteristics are recognized by recognizing a display on the travel road surface, a sign beside the travel path, or the like based on image information. It may be determined whether or not has an obstacle estimable characteristic.

  Moreover, what is necessary is just to add and install the apparatus (unit) which performs this process with respect to the existing vehicle provided with safety devices, such as a collision damage reduction brake device and a lane departure warning device. Further, when the safety device includes a camera, an inter-vehicle distance sensor, etc., sharing with the camera 2 and the inter-vehicle distance sensor 3 used in the present embodiment is possible. Thus, the present invention can be easily applied to an existing vehicle equipped with the safety device with a low cost.

  As mentioned above, although the embodiment to which the invention made by the present inventor is applied has been described, the present invention is not limited by the discussion and the drawings that form part of the disclosure of the present invention according to this embodiment. That is, it is needless to say that other embodiments, examples, operation techniques, and the like made by those skilled in the art based on this embodiment are all included in the scope of the present invention.

  The present invention is widely applicable to various vehicles as a collision damage reducing device between an obstacle and a vehicle.

1 vehicle 2 camera (imaging means)
3 Inter-vehicle distance sensor (object detection means)
4 ECU
6 Brake actuator (braking means)
10 Traveling path characteristic determination unit (traveling path determination means)
11 Collision time calculation unit (pre-collision state determination means)
12 Braking timing adjuster (pre-collision state determination means)
13 Braking control unit (braking control means)

Claims (2)

Imaging means for imaging the traveling road ahead of the traveling direction of the vehicle and outputting the image information;
Based on the image information output by the imaging means, whether or not the travel path has a characteristic that can be estimated to be an obstacle that is highly likely to collide with an object that is located far from the vehicle. Traveling path determination means for determining
An object detection means for detecting a relative distance and a relative speed between an object existing ahead in the traveling direction of the vehicle and the vehicle;
If the travel path determination means determines that the characteristic has the characteristic, before the first collision occurs, the object and the vehicle are highly likely to collide based on the relative distance and relative speed detected by the object detection means. When the travel path determination means determines that the vehicle does not have the characteristic, based on the relative distance and the relative speed detected by the object detection means, the object and the vehicle A pre-collision state determination means for determining whether or not the second pre-collision state is higher than the first pre-collision state.
The pre-collision state determining means is the case where the traveling road determining means determines that it has the characteristics, and is the first pre-collision state that occurs earlier than the second pre-collision state. When the travel path determination means determines that the braking means for generating the braking force for the vehicle generates the first braking force and does not have the characteristic, and the second collision And a braking control unit that causes the braking unit to generate a second braking force that is greater than the first braking force when the pre-collision state determination unit determines that the state is a pre-occurrence state. A collision damage mitigation device for vehicles. The vehicle collision damage reducing device according to claim 1,
The travel path determination unit calculates the number of predetermined feature points of the travel path, the lane width of the travel path, and the curvature of the travel path based on the image information output by the imaging unit, and the travel path The predetermined feature point quantity is less than or equal to a predetermined quantity, the difference between the lane width of the travel path and a preset vehicle width of the vehicle is greater than or equal to a predetermined length, and the curvature of the travel path is When the curvature is equal to or less than a predetermined curvature, it is determined that the travel path has a characteristic that can be estimated to be an obstacle that is highly likely to collide with an object that exists far away from the vehicle;
The predetermined feature point includes a display on the road surface of the traveling road.

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