JP5455602B2 - Collision damage reduction device - Google Patents

Description

  In the present invention, when it is difficult to avoid a collision with a preceding vehicle, a stopped vehicle, a falling object, etc. (hereinafter referred to as “obstacle”) located in front of the vehicle, the brake is automatically operated to reduce damage at the time of the collision. The present invention relates to a collision damage mitigation device that mitigates.

  For the determination of the brake operation of the collision damage reducing apparatus, a signal from a radar apparatus that measures a relative speed, a distance, and the like with an obstacle is used. The radar apparatus transmits an electromagnetic wave such as a millimeter wave in front of the vehicle, and performs various measurements based on a reflected wave from an obstacle (Patent Document 1).

  The radar apparatus may be able to perform various measurements on not only the obstacle ahead of the vehicle existing on the vehicle lane, but also the obstacle ahead of the vehicle located in front of the vehicle. . For example, if the preceding obstacle is a passenger car and the preceding obstacle is a large vehicle, the radar apparatus can perform various measurements on the preceding passenger car and the preceding large vehicle.

JP 2005-134266 A

  By the way, in such a traveling state, when a low-speed traveling state or a stopped state in which the preceding passenger car and the preceding large-sized vehicle are connected to each other occurs, when the large vehicle collides with the preceding passenger vehicle, the large vehicle is Even if the brake operation by the collision damage reducing device is intervening, depending on the weight of the load, there is a possibility that the preceding passenger car is sandwiched between the preceding large vehicle and sandwiched. In other words, it is assumed that a preceding passenger car that is lighter than a large vehicle is not only easily pushed forward by a collision from the rear, but also continuously pushed forward even after being collided by a preceding large vehicle. The For this reason, even if the damage of the colliding large vehicle is reduced, the collision damage of the preceding passenger car may not be reduced.

  Therefore, in view of such a conventional problem, the present invention detects an obstacle such as not only the own vehicle but also the front of the vehicle by accelerating the operation timing of the brake when the above state is detected. It is an object of the present invention to provide a collision damage reducing device that can reduce collision damage.

For this reason, in the collision damage alleviating device of the present invention, the radar that measures the direction of the obstacle located in front of the vehicle, the distance to the obstacle, the relative speed with the obstacle, and the radar reflection cross section of the obstacle, Based on the direction and distance measured by the radar, the first obstacle located closest to the obstacle in the virtual lane ahead of the host vehicle and the first obstacle located next to the first obstacle. When the first distance to the first obstacle measured by the radar and the obstacle identifying means for identifying the two obstacles is equal to or less than a collision distance at which a collision with the first obstacle cannot be avoided, A brake actuating means for automatically actuating a brake, and the second obstacle from the first speed and the own vehicle speed obtained by subtracting the first relative speed of the first obstacle from the own vehicle speed based on the measurement result of the radar; by subtracting the second relative velocity of the object 2 speed is below a first predetermined threshold, a distance from the first obstacle to the second obstacle is below a second predetermined threshold, and a radar reflection cross section of the first obstacle is below a third predetermined threshold Determining means for determining whether or not a predetermined state is present, and first changing means for changing the collision distance to a longer distance when the determination means determines that the predetermined state is established. It is characterized by that.

  According to the present invention, when the first obstacle located closest to the obstacles existing in the virtual traveling lane ahead of the host vehicle and the second obstacle located next to the first obstacle can be identified. In addition, the first speed of the first obstacle and the second speed of the second obstacle are not more than the first predetermined threshold, the distance from the first obstacle to the second obstacle is not more than the second predetermined threshold, and the first obstacle It is determined whether the radar reflection cross section of the object is in a predetermined state that is equal to or less than a third predetermined threshold. And if it is a predetermined state, it will determine with it being the low-speed driving | running | working state which the 1st obstacle and the 2nd obstacle approached, and the stop state, and will change a collision distance into a longer distance. For this reason, since the brake operation timing is advanced, it is possible to reduce the collision damage to the first obstacle as well as the own vehicle.

Overall configuration diagram of a vehicle equipped with a collision damage reducing apparatus according to the present invention Flow chart showing processing contents of control program Flow chart showing processing contents of control program

  Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 shows the overall configuration of a vehicle equipped with a collision damage reducing apparatus according to the present invention.

  The vehicle is equipped with a collision damage reduction electronic control unit (hereinafter referred to as “collision damage reduction ECU”, hereinafter the same) 10 and a brake ECU 20 that electronically controls the brake.

The collision damage reduction ECU 10 is connected to the brake ECU 20 through a network such as a CAN (Controller Area Network) so as to be able to communicate with each other. The collision damage reduction ECU 10 transmits an obstacle measurement wave such as a millimeter wave that is not easily affected by environmental factors such as bad weather and dirt to the front of the vehicle, and an obstacle located in front of the vehicle based on the reflected wave from the obstacle. Direction P (for example, the angle in the polar coordinate system with the vehicle as the origin), the distance D [m] to the obstacle, the relative velocity V [m / s] with the obstacle, and the radar reflection cross section S [dbm] ² ] When the radar 30 to be measured, the vehicle speed sensor 40 for measuring the vehicle speed Vo [m / s], the collision detection device 50 for detecting the collision, and the collision with the obstacle cannot be avoided or when there is a possibility of the collision And an alarm device 60 that issues an alarm to the driver. The collision detection device 50 detects, for example, a collision by detecting whether an airbag is activated, a sudden change in acceleration detected by an acceleration sensor, or a distortion detected by a distortion sensor provided at the front of the vehicle. The structure to detect may be sufficient. The alarm device 60 includes a warning light, a buzzer, and the like.

  The collision damage reduction ECU 10 executes a control program stored in a ROM (Read Only Memory) or the like, and estimates the vehicle weight Mo [kg] output from the brake ECU 20, the direction P output from the radar 30, and the distance. Various signals such as D, relative speed V, radar reflection cross section S, vehicle speed Vo output from the vehicle speed sensor 40, and collision detection signal output from the collision detection device 50 are acquired in a timely manner. In addition to being output from the brake ECU 20, the estimated vehicle weight Mo can be estimated based on, for example, the amount of change in the movable arm of the leveling valve that keeps the vehicle height constant if the vehicle is equipped with an air suspension.

Then, the collision damage reduction ECU 10 determines that the first distance D1 [m] to the nearest first obstacle among the obstacles existing in the virtual lane ahead of the host vehicle collides with the first obstacle. Is less than or equal to the collision distance DLo [m], a brake operation command for generating a predetermined deceleration rate αo (for example, 4.9 [m / s ² ]) is output to the brake ECU ²⁰ .

On the other hand, in the collision damage reduction ECU 10, the first obstacle and the second obstacle located next to the first obstacle among the obstacles existing in the virtual traveling lane ahead of the host vehicle are connected to each other. When it is detected that the vehicle is running at a low speed or stopped, the collision distance DLo [m] is changed to a longer distance DL1 [m], and the predetermined deceleration rate αo is changed to a larger deceleration rate α1 [m / s ² ]. To do. When the first distance D1 becomes equal to or less than the distance DL1, a brake operation command for generating the deceleration α1 is output to the brake ECU 20.

  Here, when the collision damage reduction ECU 10 executes the control program, the obstacle specifying means, the calculating means, the brake operating means, the determining means, the first and second changing means, the calculating means, and the first to third estimating means Each is embodied.

  2 and 3 show the processing contents of the control program executed by the collision damage reduction ECU 10 when the ignition switch is turned on.

  In step 1 (abbreviated as “S1” in the figure, the same applies hereinafter), the direction P of the obstacle located in front of the vehicle from the radar 30, the distance D to the obstacle, the relative speed V with respect to the obstacle, and The radar reflection cross section S of the obstacle is read, and the vehicle speed Vo is read from the vehicle speed sensor 40.

  In Step 2, based on the direction P and the distance D read from the radar 30, it is determined whether or not a first obstacle exists in the virtual traveling lane ahead of the host vehicle. The virtual travel lane is given a predetermined width, and for example, the setting is changed in a timely manner along the travel lane curvature based on the output value of the yaw rate sensor. If the first obstacle exists, the process proceeds to step 3 (Yes), while if the first obstacle does not exist, the process returns to step 1 (No).

In step 3, the first relative speed V1 [m / s] with respect to the first obstacle and the maximum deceleration rate αmax (for example, 6 to 7) using, for example, an arithmetic expression of DLo = V1 ² / (2 × αmax). From [m / s ² ]), a collision distance DLo [m] that cannot avoid a collision with the first obstacle is calculated. The maximum deceleration αmax is the maximum deceleration that the vehicle can generate.

  In step 4, based on the direction P and the distance D read from the radar 30, it is determined whether or not there is a second obstacle in the virtual traveling lane ahead of the host vehicle. If the second obstacle does not exist, it is determined that the state before the first obstacle and the second obstacle are not connected, and the process proceeds to step 5 (Yes), while the second obstacle exists. Then, it is determined that the state before the first obstacle and the second obstacle are connected, and the process proceeds to Step 13 (No).

  In step 5, it is determined whether or not the first distance D1 to the first obstacle is equal to or less than the collision distance DLo. If the first distance D1 is equal to or smaller than the collision distance DLo, the process proceeds to step 6 (Yes), while if the first distance D1 is larger than the collision distance DLo, the process proceeds to step 10 (No).

  In step 6, a brake operation command for generating a predetermined deceleration rate αo is appropriately output to the brake ECU 20, and the brake is operated to decelerate. Thereby, the damage at the time of colliding with the 1st obstacle can be aimed at.

  In step 7, the warning device 60 is activated to warn the vehicle driver that a collision with the first obstacle cannot be avoided. Thereby, it is possible to inform the vehicle driver that the collision cannot be avoided and prepare for the collision.

  In step 8, the brake operation state is maintained until the vehicle speed Vo measured by the vehicle speed sensor 40 becomes zero. This ensures the reduction of damage when colliding with the first obstacle.

  In step 9, a brake operation release command is output as appropriate to the brake ECU 20, the brake operation state is released, and the process ends.

  In step 10, for example, using an arithmetic expression of Da1 = DLo + (tL × V1), the collision distance DLo, the margin time tL (for example, 0.8 [s]) until the brake operation starts, and the first relative speed V1 From this, the first alarm start distance Da1 [m] for starting an alarm that there is a possibility of colliding with the first obstacle is calculated.

  In step 11, it is determined whether or not the first distance D1 is less than the first alarm start distance Da1. If the first distance D1 is less than the first alarm start distance Da1, the process proceeds to step 12 (Yes), while if the first distance D1 is equal to or greater than the first alarm start distance Da1, the process returns to step 1 (No). .

  In step 12, the alarm device 60 is activated to warn the vehicle driver that there is a risk of collision with the first obstacle. As a result, it is possible to inform the vehicle driver that there is a risk of a collision and to call attention.

In step 13, for example, the vehicle speed Vo, the first distance D1, the first relative speed V1, and the second obstacle are calculated using the arithmetic expressions of Vo1 = Vo-V1 , Vo2 = Vo-V2 , and Dd = D2-D1-L1. From the second distance D2 [m] to the second relative speed V2 [m / s] with the second obstacle, and the total length L1 of the first obstacle that is a constant (for example, 4.4 [m]), The first speed Vo1 [m / s] of the first obstacle, the second speed Vo2 [m / s] of the second obstacle, and the distance Dd [m] from the first obstacle to the second obstacle are calculated.

In step 14, each of the first speed Vo1 and the second speed Vo2 is equal to or less than a first predetermined threshold value Vt (for example, 1 [m / s]), and the distance Dd [m] is a second predetermined threshold value Dt (for example, 1 [m ]) And whether the radar obstacle sectional area So [dbm ² ] of the first obstacle is equal to or smaller than a third predetermined threshold St (for example, 20 [dbm ² ]) is determined. The radar cross section is, for example, about 15 [dbm ² ] for passenger cars and about 30 [dbm ² ] for large vehicles. And if it is a predetermined state, while determining that this is a low-speed driving state or a stopped state in which the first obstacle and the second obstacle are close to each other and proceeding to Step 15 (Yes), the predetermined obstacle If not, the process proceeds to step 5 (No).

In step 15, the collision distance DLo is changed to a longer distance DL1. For example, the distance DL1 is a fixed length. Further, for example, the vehicle speed Vo and the first speed Vo1 are calculated using an arithmetic expression of DL1 = {(Vo−Vo1) × (Vo−Va) / αo} − {(Vo−Va) ² / (2 × αo)}. The distance DL1 is calculated from the vehicle speed Va [m / s] before the collision estimated just before the collision with the first obstacle and the predetermined deceleration rate αo, and the collision distance DLo is changed to the calculated distance DL1. it can. Here, the vehicle speed Va before the collision is, for example, estimated vehicle weight Mo read from the brake ECU 20 using an arithmetic expression Va = {(Mo + M1) / Mo) × Vc} − {(M1 / Mo) × Vo1). Based on the constant weight M1 of the first obstacle (for example, 500 to 1000 [kg]), the post-collision vehicle speed Vc [m / s] estimated from the vehicle speed immediately after the collision with the first obstacle, and the first speed Vo1. Calculate. The post-collision vehicle speed Vc is calculated from the second obstacle Vo2 to the predetermined obstacle αo and the first obstacle calculated in Step 13 by using, for example, an equation Vc = Vo2 + √ (2 × αo × Dd). It calculates from the distance Dd to an object. Thereby, since the collision distance DLo can be changed to the longer distance DL1, the operation timing of the brake can be advanced.

In step 16, the predetermined deceleration rate αo is changed to a larger deceleration rate α1. For example, the deceleration α1 is the maximum deceleration αmax. Further, for example, the deceleration α1 may be a deceleration (for example, 5.5 [m / s ² ]) that is greater than the predetermined deceleration αo and equal to or less than the maximum deceleration αmax. Further, for example, the vehicle speed Vo and the first speed Vo1 are calculated using an arithmetic expression of α1 = {(Vo−Vo1) × (Vo−Va) / DLo} − {(Vo−Va) ² / (2 × DLo)}. The deceleration α1 can be calculated from the vehicle speed Va before the collision and the collision distance DLo, and the predetermined deceleration αo can be changed to the calculated deceleration α1. As a result, it is possible to output a brake operation command that generates a deceleration α1 larger than the predetermined deceleration αo.

  In step 17, it is determined whether or not the first distance D1 is less than or equal to the distance DL1. If the first distance D1 is equal to or less than the distance DL1 that accelerates the brake operation timing, the process proceeds to step 18 (Yes), whereas if the first distance D1 is greater than the distance DL1, the process proceeds to step 19 (No).

  In step 18, a brake operation command for generating a deceleration α1 is appropriately output to the brake ECU 20, and the brake is operated so that the first obstacle existing between the host vehicle and the second obstacle is not sandwiched. Let me slow down. Thereby, the collision damage with respect to a 1st obstacle can be reduced.

  In step 19, for example, using the arithmetic expression Da2 = DL1 + (tL × V1), an alarm is given that there is a possibility of colliding with the first obstacle from the distance DL1, the margin time tL, and the first relative speed V1. A second alarm start distance Da2 [m] for starting is calculated.

  In step 20, it is determined whether or not the first distance D1 is less than the second alarm start distance Da2. If the first distance D1 is less than the second alarm start distance Da2, the process proceeds to step 12, while if the first distance D1 is equal to or greater than the second alarm start distance Da2, the process returns to step 1 (No).

  According to the collision damage reducing device, when the first obstacle and the second obstacle are specified, the speeds Vo1 and Vo2 of the first obstacle and the second obstacle, and the first obstacle to the second obstacle. And the first speed Vo1 and the second speed Vo2 are equal to or smaller than the first predetermined threshold value Vt, the distance Dd is equal to or smaller than the second predetermined threshold value Dt, and the radar reflection cross section So is equal to or smaller than the third predetermined threshold value St. Is determined to be a low-speed traveling state or a stopped state in which the first obstacle and the second obstacle are closely connected to each other, and the collision distance DLo that cannot avoid the collision with the obstacle is set to a longer distance DL1. And the predetermined deceleration rate αo is changed to a larger deceleration rate α1. Therefore, the brake can be operated at a timing earlier than the collision distance DLo before the change, and the brake operation command for generating the deceleration α1 larger than the predetermined deceleration αo can be output. It is also possible to reduce collision damage against obstacles.

  In the above embodiment, the collision distance DLo is changed to the longer distance DL1, and the brake operation timing is advanced. However, based on the first distance D1 and the first relative velocity V1 measured by the radar 30, the collision time t [s] until the collision with the first obstacle is calculated, and this collision time t is calculated as the fourth predetermined threshold value. If the configuration is such that the brake is automatically operated when it becomes less than to (for example, 1.6 [s]), the fourth predetermined threshold value to is changed to a longer time to1, and the brake operation timing is changed. An early configuration may be used. For example, the time to1 is a fixed value (for example, 1.8 [s]). The collision time t can be calculated from the first distance D1 and the first relative speed V1, for example, using an arithmetic expression t = D1 / V1.

Further, step 13 and step 14 may be changed as follows. For example, step 13 is performed by using the arithmetic expression Vd = Vo1−Vo2 and t2 = Dd / (Vo2−Vo1) from the first speed Vo1, the second speed Vo2, and the distance Dd. A speed difference Vd [m / s] from the obstacle and a collision time t2 [s] until the first obstacle collides with the second obstacle are calculated. In step 14, the speed difference Vd [m / s] is within the fifth predetermined threshold value Vdt (for example, −1.4 [m / s] ≦ Vd ≦ 1.4 [m / s]), and the collision time t2 [S] is equal to or less than a sixth predetermined threshold value t3 (for example, 1 [s]), and the radar reflection sectional area So [dbm ² ] of the first obstacle is the third predetermined threshold value St (for example, 20 [dbm ² ]). It may be configured to determine whether or not a predetermined state is as follows. In step 14, for example, the rear shape is specified based on the rear image of the first obstacle imaged by the camera, and the determination as to whether or not the rear shape is other than the large vehicle may be included. .

  Furthermore, step 15 and step 16 may have only one of the configurations, or may have a configuration in which the order is reversed. If the distance DL1 is calculated in step 16 when the order is reversed, the predetermined deceleration rate αo used for the calculation may be changed to the deceleration rate α1 changed in step 15. However, when the deceleration α1 is the maximum deceleration αmax, the predetermined deceleration αo is changed to the maximum deceleration αmax. In addition, in the calculation of the deceleration α1 and the distance DL1, it is possible to adopt a configuration in which the number of the first obstacle is recognized by the camera and the total length L1 and the weight M1 of the first obstacle are handled as variables. In this case, for example, if it is a mini vehicle, the total length L1 is 3.4 [m] and the weight M1 is 1000 [kg], and if it is a 5-number vehicle, the total length L1 is 4.7 [m] and the weight M1 is 1500 [kg]. If the vehicle is a 3-number car, the total length L1 is set to 6 [m] and the weight M1 is set to 2000 [kg]. Thereby, the distance DL1 and the deceleration α1 can be calculated in more detail.

10 Collision damage reduction ECU
20 Brake ECU
30 Radar 40 Vehicle speed sensor 50 Collision detection device 60 Alarm device

Claims (5)

A radar that measures the direction of the obstacle located in front of the vehicle, the distance to the obstacle, the relative velocity with the obstacle, and the radar cross section of the obstacle;
Based on the direction and distance measured by the radar, the first obstacle located closest to the obstacle in the virtual lane ahead of the host vehicle and the second obstacle located next to the first obstacle. Obstacle identification means for identifying obstacles;
Brake operating means for automatically operating a brake when a first distance to the first obstacle measured by the radar is equal to or less than a collision distance at which a collision with the first obstacle cannot be avoided;
Based on the measurement result of the radar, a first speed obtained by subtracting the first relative speed of the first obstacle from the own vehicle speed and a second speed obtained by subtracting the second relative speed of the second obstacle from the own vehicle speed. Is a predetermined state in which the distance from the first obstacle to the second obstacle is not more than a second predetermined threshold, and the radar reflection cross-sectional area of the first obstacle is not more than a third predetermined threshold Determining means for determining whether or not
First changing means for changing the collision distance to a longer distance when it is determined by the determining means to be in a predetermined state;
A collision damage mitigation device comprising:   2. The apparatus according to claim 1, further comprising second changing means for changing a predetermined deceleration to be generated by the brake to a larger deceleration when it is determined by the determination means that the state is a predetermined state. The collision damage mitigation device described. And a calculation means for calculating the collision distance based on a first relative speed to the first obstacle measured by the radar and a maximum deceleration that can be generated by the brake. The collision damage reducing device according to claim 2 . First estimating means for estimating the weight of the vehicle;
Based on the predetermined deceleration , the second speed of the second obstacle, and the distance from the first obstacle to the second obstacle, the vehicle speed after the collision immediately after the collision with the first obstacle. Second estimation means for estimating
Based on the first speed of the first obstacle, the estimated vehicle weight estimated by the first estimating means, the weight of the first obstacle, and the post-collision vehicle speed estimated by the second estimating means. Third estimating means for estimating a vehicle speed before the collision just before colliding with the first obstacle,
And further comprising
The second changing unit is configured to reduce the predetermined decrease based on the own vehicle speed , the first speed of the first obstacle, the vehicle speed before the collision estimated by the third estimating unit, and the collision distance. 4. The collision damage reducing apparatus according to claim 3 , wherein a deceleration larger than a speed is calculated, and the collision deceleration is changed to the calculated deceleration. The first changing means is based on the own vehicle speed , the first speed of the first obstacle, the vehicle speed before the collision estimated by the third estimating means, and the predetermined deceleration. 5. The collision damage reducing apparatus according to claim 4, wherein a distance longer than the distance is calculated and the collision distance is changed to the calculated distance.

Images