Collision detection device, collision detection method, and collision detection program

Abstract

To provide a collision detection device which has high robustness to a failure in an acceleration sensor for safing determination and excellent frontal collision detection performance, while suppressing increase in device cost.SOLUTION: A collision detection device (15) includes a first acceleration acquisition part (151), a second acceleration acquisition part (152), and a frontal collision determination part (153). The first acceleration acquisition part acquires longitudinal direction acceleration output from a left side sensor (13L) and a right side sensor (13R). The second acceleration acquisition part (152) acquires longitudinal direction acceleration output from a main sensor (14) that is an acceleration sensor different from the left side sensor and the right side sensor. The frontal collision determination part determines occurrence of frontal collision, on the basis of safing determination based on the longitudinal direction acceleration acquired by the first acceleration acquisition part, and main determination based on the longitudinal direction acceleration acquired by the second acceleration acquisition part.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a collision detection device, a collision detection method, and a collision detection program for detecting a frontal collision of a vehicle.

Background Art

[0002] The airbag ECU described in Patent Document 1 includes a main sensor and a safing sensor which are acceleration sensors, and a control unit. ECU is an abbreviation for Electronic Control Unit. The control unit controls the deployment / non-deployment of the airbag based on the detection results of the main sensor and the safing sensor. Specifically, when the detection result of the safing sensor exceeds the safing threshold value, the control unit prepares for the deployment of the airbag, and when the detection result of the main sensor exceeds the main threshold value, it determines that the deployment condition is satisfied and gives an instruction to deploy the airbag. The safing threshold value is set to a value smaller than the main threshold value.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The configuration described in Patent Document 1 provides a safing determination sensor in the airbag ECU, which leads to an increase in device cost. On the other hand, a system using a so-called front sensor arranged in front of the vehicle as a safing determination sensor has also been proposed. However, from the viewpoint of robustness against sensor failures and disconnection during a frontal collision, it is considered that providing a safing determination sensor in the airbag ECU as in the configuration described in Patent Document 1 is superior.

[0005] The present invention has been made in view of the circumstances exemplified above. That is, the present invention provides a collision detection device that has high robustness against failures in an acceleration sensor for safing determination and excellent performance in frontal collision detection, while suppressing an increase in device cost.

Means for Solving the Problems

[0006] The collision detection device (15) is configured to detect a frontal collision of the vehicle (1). The collision detection device according to claim 1 A first acceleration acquisition unit (151) that is provided on the left side portion of the vehicle body (2) of the vehicle and detects the longitudinal acceleration and the lateral acceleration, and acquires the longitudinal acceleration output from a left side sensor (13L) that is an acceleration sensor, and Two axes A right side sensor (13R) that is provided on the right side portion of the vehicle body and detects the longitudinal acceleration and the lateral acceleration, and acquires the longitudinal acceleration output from the right side sensor (13R) that is an acceleration sensor, and Two axes A second acceleration acquisition unit (152) that acquires the longitudinal acceleration output from a main sensor (14) that is an acceleration sensor different from the left side sensor and the right side sensor and detects the longitudinal acceleration, and A frontal collision determination unit (153) that determines the occurrence of the frontal collision based on a safing determination based on the longitudinal acceleration acquired by the first acceleration acquisition unit and a main determination based on the longitudinal acceleration acquired by the second acceleration acquisition unit. And is provided with. Is a program executed by a collision detection device (15) configured to detect a frontal collision of the vehicle (1), The process executed by the collision detection device is The collision detection program according to 6 A left side sensor (13L) that is an acceleration sensor provided on the left side portion of the vehicle body (2) of the vehicle and detects the longitudinal acceleration and the lateral acceleration, and a right side sensor (13R) that is provided on the right side portion of the vehicle body and detects the longitudinal acceleration and the lateral acceleration. And is provided with. The process executed by the collision detection device is Two axes A left side sensor (13L) that is an acceleration sensor provided on the left side portion of the vehicle body (2) of the vehicle and detects the longitudinal acceleration and the lateral acceleration, and a right side sensor (13R) that is provided on the right side portion of the vehicle body and detects the longitudinal acceleration and the lateral acceleration. Two axesA process of obtaining the longitudinal acceleration output from the right side sensor (13R) which is an acceleration sensor, A process of obtaining the longitudinal acceleration output from the main sensor (14) which is an acceleration sensor different from the left side sensor and the right side sensor and detects the longitudinal acceleration, A process of determining the occurrence of the frontal collision based on a safing determination based on the obtained longitudinal acceleration and a main determination based on the obtained longitudinal acceleration, including.

[0007] In each column of the application documents, each element may be given a reference sign with parentheses. However, such reference signs are merely illustrative of an example of the correspondence between the same element and the specific means described in the embodiments described later. Therefore, the present invention is not limited in any way by the description of the above reference signs.

Brief Description of Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Mode for Carrying Out the Invention

[0009] (Embodiment) Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that for various modification examples applicable to one embodiment, if they are inserted in the middle of the series of explanations regarding the embodiment, there is a possibility that the understanding of the embodiment may be hindered. For this reason, the modification examples will be collectively described after the series of explanations of the embodiments in a coherent manner.

[0010] (Vehicle-mounted System Configuration) First, with reference to FIG. 1, the schematic configuration of the vehicle 1 to which the embodiment is applied will be described. For convenience of explanation, an XYZ three-dimensional coordinate system is set as shown in the figure. The X-axis direction is the front-rear direction, that is, the vehicle overall length direction, and is parallel to the vehicle center line LC. The vehicle center line LC is an imaginary straight line passing through the center point in the plan view of the vehicle 1. The positive X-axis direction corresponds to the vehicle traveling direction during forward travel. The Y-axis direction is the left-right direction, that is, the vehicle width direction. The Z-axis direction is the vehicle height direction, and is parallel to the direction of gravity in a state where the vehicle 1 is stably placed on a horizontal plane in a drivable state.

[0011] The vehicle 1 is a so-called automobile and has a box-shaped vehicle body 2. A front bumper 4 is attached to the front surface 3 of the vehicle body 2. A rear bumper 6 is attached to the rear surface 5 of the vehicle body 2. A side panel 8 such as a door panel is attached to the side surface 7 of the vehicle body 2.

[0012] The vehicle 1 is equipped with an in-vehicle system 10. The vehicle 1 equipped with the in-vehicle system 10 according to the present embodiment is hereinafter referred to as the "host vehicle". The in-vehicle system 10 is configured to control the activation of the occupant protection device 11 mounted on the host vehicle. That is, the in-vehicle system 10, which may also be referred to as an occupant protection system, is provided to protect the occupants of the host vehicle by the occupant protection device 11 when an object existing outside the host vehicle collides with the host vehicle.

[0013] In this embodiment, the occupant protection device 11 is a protection device for frontal collision, and includes a driver's seat airbag, a passenger seat airbag, and the like. "Frontal collision" refers to a collision in which an impact is applied to the vehicle body 2 from the front, and is also referred to as "frontal impact". Frontal collision includes head-on collision, offset frontal collision, and oblique frontal collision. A head-on collision is a frontal collision with an overlap rate of almost 100%. The overlap rate is the ratio of the vehicle width direction dimension of the collision area between the vehicle body 2 and the collision target object to the vehicle width. The vehicle width is the vehicle width direction dimension of the vehicle body 2. A head-on collision can also be referred to as a full lap frontal collision. An offset frontal collision is a frontal collision with an overlap rate of a predetermined value (for example, 90%) or less. An oblique frontal collision is a frontal collision in which a corner of the front surface 3 of the vehicle body 2 collides with a collision target object having a longitudinal or lateral direction inclined with respect to the vehicle center line LC in a plan view. An oblique frontal collision is also referred to as "oblique collision" or "oblique offset collision". A typical example of an oblique frontal collision is a collision pattern at a relative angle of 15° and an overlap rate of about 35%, corresponding to the test conditions in the oblique collision test defined by NHTSA. NHTSA is the abbreviation of National Highway Traffic Safety Administration. Frontal collisions other than head-on collisions are referred to as "asymmetric collisions". That is, an asymmetric collision is a collision pattern in which either the left or right side of the front surface 3 of the vehicle body 2 collides with a collision target object such as another vehicle.

[0014] At the front part of the vehicle body 2, a front sensor 12 is provided. The front sensor 12 is mounted on a vehicle body part (not shown) that supports the front bumper 4 from the inside of the vehicle body 2. A pair of left and right front sensors 12 are provided. That is, on the vehicle body 2, a left front sensor 12L and a right front sensor 12R are mounted. The left front sensor 12L and the right front sensor 12R are symmetrically arranged with the vehicle center line LC interposed therebetween. The front sensor 12 is a so-called uniaxial sensor, which is configured to detect the longitudinal acceleration (i.e., the X-axis direction acceleration) acting on the vehicle body 2 when a collision occurs between the host vehicle and an object, and output the detection result.

[0015] On the left and right side parts of the vehicle body 2, side sensors 13 are provided. That is, the side sensors 13 are arranged at both ends in the vehicle width direction and the middle part (e.g., substantially the center part) in the vehicle full length direction of the vehicle body 2. Specifically, on the vehicle body 2, a left side sensor 13L and a right side sensor 13R are mounted. The left side sensor 13L and the right side sensor 13R are symmetrically arranged with the vehicle center line LC interposed therebetween. The side sensor 13 is a so-called biaxial sensor, which is configured to detect the lateral acceleration (i.e., the Y-axis direction acceleration) and the longitudinal acceleration acting on the vehicle body 2 when a collision occurs between the host vehicle and an object, and output the detection result.

[0016] In addition to the occupant protection device 11, the front sensor 12, and the side sensor 13, the in-vehicle system 10 includes a main sensor 14. The main sensor 14 is arranged on the vehicle center line LC in a plan view and is housed inside the vehicle body 2. The main sensor 14 is a so-called uniaxial sensor, which is configured to detect the longitudinal acceleration acting on the vehicle body 2 when a collision occurs between the host vehicle and an object, and output the detection result. The main sensor 14, which is a floor sensor, is built into the electronic control unit 15.

[0017] (Collision Detection Device) The electronic control device 15 has a configuration as a so-called airbag ECU. That is, in the present embodiment, the electronic control device 15 that functions as a collision detection device detects a frontal collision of the host vehicle based on the outputs of the front sensor 12, the side sensor 13, and the main sensor 14, and is configured to activate the occupant protection device 11 for frontal collision. Specifically, the electronic control device 15 has a configuration as an in-vehicle microcomputer including a CPU, a ROM, a RAM, a non-volatile rewritable memory, etc., which are not shown in the figure. The non-volatile rewritable memory is a storage device that can rewrite information during power-on while retaining the information in a non-rewritable manner during power-off, and is, for example, a flash ROM or the like. The ROM, the RAM, and the non-volatile rewritable memory are non-transitory physical storage media. The electronic control device 15 is configured to control the operation of the in-vehicle system 10 by reading and executing a control program stored in the ROM or the non-volatile rewritable memory.

[0018] As shown in FIG. 2, the electronic control unit 15 includes, as a functional configuration realized by executing a program on an in-vehicle microcomputer, a first acceleration acquisition unit 151, a second acceleration acquisition unit 152, and a frontal collision determination unit 153. The first acceleration acquisition unit 151 acquires the longitudinal acceleration output from the side sensors 13, that is, the left side sensor 13L and the right side sensor 13R, and outputs it to the frontal collision determination unit 153. That is, the first acceleration acquisition unit 151 is configured to receive the output signals of the longitudinal acceleration from the left side sensor 13L and the right side sensor 13R. The second acceleration acquisition unit 152 acquires the longitudinal acceleration output from the main sensor 14, which is an acceleration sensor different from the left side sensor 13L and the right side sensor 13R, and outputs it to the frontal collision determination unit 153. That is, the second acceleration acquisition unit 152 is configured to receive the output signal of the longitudinal acceleration from the main sensor 14. The frontal collision determination unit 153 is configured to determine the occurrence of a frontal collision based on the longitudinal acceleration acquired by the first acceleration acquisition unit 151 and the second acceleration acquisition unit 152. Specifically, the frontal collision determination unit 153 determines the occurrence of a frontal collision based on a safing determination based on the longitudinal acceleration acquired by the first acceleration acquisition unit 151 and a main determination based on the longitudinal acceleration acquired by the second acceleration acquisition unit 152.

[0019] More specifically, as shown in FIG. 3, the frontal collision determination unit 153 has, as a logic configuration for frontal collision determination, a main determination logic 153a, a safing determination logic 153b, and a frontal collision determination logic 153c. The main determination logic 153a is configured to turn on the main determination (i.e., output a logical value “1”) when the longitudinal acceleration output from the main sensor 14 and acquired by the second acceleration acquisition unit 152 exceeds a predetermined main determination threshold value. On the other hand, the main determination logic 153a is configured to turn off the main determination (i.e., output a logical value “0”) when the longitudinal acceleration acquired by the second acceleration acquisition unit 152 does not exceed the main determination threshold value. The safing determination logic 153b is configured to output a safing determination result. That is, the safing determination logic 153b is configured to output a logical value “1” when the safing determination that a frontal collision has occurred is established, and output a logical value “0” when the safing determination is not established. The frontal collision determination logic 153c is an AND gate and is configured to output a logical product of the output of the main determination logic 153a and the output of the safing determination logic 153b. That is, the frontal collision determination logic 153c is configured to determine that a frontal collision has occurred (i.e., output a logical value “1”) when both the main determination and the safing determination are established. On the other hand, the frontal collision determination logic 153c is configured to determine that no frontal collision has occurred (i.e., output a logical value “0”) when at least one of the main determination and the safing determination is not established.

[0020] The safing determination logic 153b has a left determination logic 153d, a right determination logic 153e, and an OR gate 153f. The left determination logic 153d turns on the left safing determination (i.e., outputs a logical value "1") when the longitudinal acceleration output from the left side sensor 13L and acquired by the first acceleration acquisition unit 151 exceeds a predetermined safing determination threshold value. On the other hand, the left determination logic 153d turns off the left safing determination (i.e., outputs a logical value "0") when the longitudinal acceleration acquired by the first acceleration acquisition unit 151 does not exceed the safing determination threshold value. The right determination logic 153e turns on the right safing determination (i.e., outputs a logical value "1") when the longitudinal acceleration output from the right side sensor 13R and acquired by the first acceleration acquisition unit 151 exceeds a predetermined safing determination threshold value. On the other hand, the right determination logic 153e turns off the left safing determination (i.e., outputs a logical value "0") when the longitudinal acceleration acquired by the first acceleration acquisition unit 151 does not exceed the safing determination threshold value. The OR gate 153f outputs the logical sum of the output of the left determination logic 153d and the output of the right determination logic 153e. That is, the safing determination logic 153b turns on the safing determination (i.e., outputs a logical value "1") when at least one of the left safing determination and the right safing determination is established. On the other hand, the safing determination logic 153b turns off the safing determination (i.e., outputs a logical value "0") when neither the left safing determination nor the right safing determination is established.

[0021] Also, as shown in FIG. 2, the electronic control unit 15 includes a threshold setting unit 154 and a sensor information acquisition unit 155 as functional configurations realized by executing a program on an in-vehicle microcomputer. The threshold setting unit 154 is configured to set a safing determination threshold, which is a threshold for safing determination by the safing determination logic 153b in the frontal collision determination unit 153. That is, the frontal collision determination unit 153 is configured to perform a safing determination indicating that a frontal collision has occurred when the longitudinal acceleration detected by the left side sensor 13L or the right side sensor 13R exceeds the safing determination threshold. The sensor information acquisition unit 155 is configured to acquire sensor diagnosis information indicating whether the left side sensor 13L and the right side sensor 13R are normal or faulty. In this embodiment, when one of the left side sensor 13L and the right side sensor 13R is faulty and the other is not, the threshold setting unit 154 is configured to execute a predetermined sensitization process. The sensitization process is a process of lowering the safing determination threshold for the longitudinal acceleration detected by the other sensor different from the faulty one compared to the case where both are not faulty. The faulty one of the sensors corresponds to the "first side sensor" in the present invention. The other sensor that is not faulty corresponds to the "second side sensor" in the present invention.

[0022] Furthermore, as a functional configuration realized by executing a program on an in-vehicle microcomputer, the electronic control device 15 includes an asymmetric collision determination unit 156. The asymmetric collision determination unit 156 is configured to determine that a frontal collision is an asymmetric collision. When the asymmetric collision determination unit 156 determines an asymmetric collision, the threshold setting unit 154 is configured to execute a sensitization process. In the present embodiment, the asymmetric collision determination unit 156 is capable of determining a left-right collision, that is, whether the asymmetric collision is a collision on the right side or the left side of the host vehicle. When the asymmetric collision determination unit 156 determines an asymmetric collision and the failed one of the sensors is a collision-side sensor, the threshold setting unit 154 is configured to execute a sensitization process. The "collision-side sensor" means, when the host vehicle is divided into left and right by the vehicle center line LC, with one side being the first region and the other side being the second region, and an asymmetric collision occurs in a manner of colliding with an object in the first region, the sensor that exists in the first region among the left side sensor 13L and the right side sensor 13R. The sensor that is not the collision-side sensor when an asymmetric collision occurs among the left side sensor 13L and the right side sensor 13R is referred to as the "non-collision-side sensor". As shown in FIG. 4, when the left front part of the host vehicle collides with another vehicle BV, the left side sensor 13L corresponds to the collision-side sensor and the right side sensor 13R corresponds to the non-collision-side sensor. After executing the sensitization process, when a predetermined time has elapsed, the threshold setting unit 154 is configured to reset the sensitization process.

[0023] (Operation Outline) Hereinafter, regarding the operation outline of the present embodiment, with reference to FIGS. 1 to 7, using as a specific example the case where the left front part of the host vehicle collides with another vehicle BV as shown in FIG. 4, the effects achieved by the present embodiment will be described. Note that the device configuration according to the present embodiment, the collision detection method and the collision detection program executed thereby may be collectively referred to as "the present embodiment".

[0024] As a conventional technique, a configuration in which a sensor for safing determination is provided in an airbag ECU or a configuration in which the front sensor 12 is used as a sensor for safing determination is known. In this regard, from the viewpoint of robustness against sensor failures and disconnection during a frontal collision, it is better to provide a sensor for safing determination in the airbag ECU as in the former configuration. However, in such a configuration, since a sensor for safing determination is provided in the airbag ECU, it leads to an increase in device cost. For this reason, in recent years, there has been a demand to have high robustness against disconnection and sensor failures and to suppress an increase in device cost as much as possible.

[0025] Therefore, the inventor of the present invention has found that by using a biaxial sensor as the side sensor 13 and performing safing determination for a frontal collision using the longitudinal acceleration detected by such a biaxial sensor, the above problems can be solved. FIG. 5 shows an example of the output waveform of each of the pair of side sensors 13 when an offset frontal collision occurs in the mode shown in FIG. 4. In FIG. 5, the horizontal axis t represents time, the vertical axis Gx represents longitudinal acceleration, "L" represents the output waveform of the left side sensor 13L, "R" represents the output waveform of the right side sensor 13R, and the dashed-dotted line represents the safing determination threshold. In this example, it is assumed that the left and right safing determination thresholds are the same. According to such a configuration, by performing safing determination using the side sensor 13 that receives less damage during a frontal collision, the robustness against disconnection during a frontal collision is improved. Further, safing determination can be performed without providing a sensor for safing determination in the electronic control unit 15 which is an airbag ECU, and the device cost can be reduced.

[0026] Note that when the collision speed, that is, the relative speed between the host vehicle and the other vehicle BV is low, as shown in FIG. 6, the output of the non-collision side sensor may become small and may not exceed the normal safing determination threshold value. In this regard, in the present embodiment, even when the collision side sensor fails, a sensitization process is executed to lower the safing determination threshold value to a low threshold value as indicated by the two-dot chain line in FIG. 6 so that the safing determination can be favorably performed based on the output of the non-collision side sensor. Thereby, the safing determination for the occurrence of a frontal collision using the side sensor 13 can be favorably performed.

[0027] As described above, the phenomenon in which the output of the non-collision side sensor becomes small occurs in an asymmetric collision. Therefore, in the present embodiment, the asymmetric collision determination unit 156 determines an asymmetric collision, and when the collision side sensor fails, a sensitization process for the non-collision side sensor is executed. The determination of an asymmetric collision can be performed using, for example, the front sensor 12, a collision detection sensor provided in the front bumper 4 for activating the pedestrian protection device, or an ADAS system sensor (such as a camera). Thereby, the occupant protection device 11 for a frontal collision can be activated more accurately.

[0028] In order to further improve the activation control of the occupant protection device 11 for a frontal collision, the sensitization process by lowering the safing determination threshold value needs to be performed within the minimum necessary range. Therefore, in the present embodiment, the sensitization process is performed only when a sensor failure and an asymmetric collision occur. Further, in the present embodiment, when a predetermined time has elapsed after the sensitization process is executed, the sensitization process is reset. The "predetermined time" is the time that is normally assumed between the establishment of the main determination and the establishment of the safing determination when a frontal collision that requires activation of the occupant protection device 11 for a frontal collision occurs. Specifically, the point in time when the predetermined time has elapsed corresponds to the ignition timing of the second-stage squib. The elapse of the predetermined time can be performed using, for example, a timer (not shown) provided in the electronic control unit 15.

[0029] FIG. 7 shows an overview of the frontal collision determination process by the electronic control unit 15 according to the present embodiment. In the flowchart shown in FIG. 7, "S" is an abbreviation for "step".

[0030] First, in step 701, the electronic control unit 15 acquires sensor diagnosis information indicating whether the left side sensor 13L and the right side sensor 13R are normal or faulty, and determines whether a fault has occurred in any of the sensors. If no fault has occurred in any of the sensors (i.e., step 701 = NO), the electronic control unit 15 executes the process of step 702. In step 702, the electronic control unit 15 sets the safing determination threshold values of the left determination logic 153d and the right determination logic 153e in the safing determination logic 153b to the normal threshold values.

[0031] On the other hand, if a fault has occurred in any of the sensors (i.e., step 701 = YES), the electronic control unit 15 executes the process of step 703. In step 703, the electronic control unit 15 determines whether a collision has occurred based on the output of the main sensor 14. The process of step 703 corresponds to the main determination. If the main determination is not established (i.e., step 703 = NO), the electronic control unit 15 executes the process of step 704. In step 704, the electronic control unit 15 sets the safing determination threshold value corresponding to the non-faulty sensor among the left determination logic 153d and the right determination logic 153e in the safing determination logic 153b to the normal threshold value.

[0032] When the main determination is established (i.e., step 703 = YES), the electronic control unit 15 executes the process of step 705. In step 705, the electronic control unit 15 determines whether the collision determined to have occurred due to the establishment of the main determination is an asymmetric collision. If it is not an asymmetric collision (i.e., step 705 = NO), the electronic control unit 15 executes the process of step 704. On the other hand, if it is an asymmetric collision (i.e., step 705 = YES), the electronic control unit 15 executes the process of step 706. In step 706, the electronic control unit 15 determines whether the sensor determined to be faulty in step 701 is a collision-side sensor. If the faulty sensor is a non-collision-side sensor (i.e., step 706 = NO), the electronic control unit 15 executes the process of step 704. That is, when the non-faulty sensor is a collision-side sensor rather than a non-collision-side sensor, even the normal threshold can be used to make a good safing determination. Therefore, the electronic control unit 15 sets the safing determination threshold corresponding to the non-faulty collision-side sensor among the left-side determination logic 153d and the right-side determination logic 153e in the safing determination logic 153b to the normal threshold. On the other hand, if the faulty sensor is a collision-side sensor (i.e., step 706 = YES), the electronic control unit 15 executes the process of step 707. In step 707, the electronic control unit 15 performs a sensitization process. That is, the electronic control unit 15 sets the safing determination threshold corresponding to the non-faulty non-collision-side sensor among the left-side determination logic 153d and the right-side determination logic 153e in the safing determination logic 153b to a low threshold.

[0033] After performing the sensitization process in step 707, in step 708, the electronic control unit 15 determines whether a predetermined time has elapsed since the sensitization process was executed. Before the predetermined time has elapsed (i.e., step 708 = NO), the electronic control unit 15 maintains the low threshold setting state due to the sensitization process. On the other hand, when the predetermined time has elapsed (i.e., step 708 = YES), the electronic control unit 15 resets the low threshold setting state due to the sensitization process and sets the safing determination threshold corresponding to the non-faulty non-collision-side sensor to the normal threshold.

[0034] (Modification example) The present invention is not limited to the above-described embodiment. Therefore, the above-described embodiment can be appropriately modified. Hereinafter, typical modification examples will be described. In the description of the following modification examples, the differences from the above-described embodiment will be mainly described. Also, in the above-described embodiment and the modification examples, the same or equivalent parts are denoted by the same reference numerals. Therefore, in the description of the following modification examples, for the components having the same reference numerals as those in the above-described embodiment, the description in the above-described embodiment can be appropriately incorporated unless there is a technical contradiction or a special additional explanation.

[0035] The present invention is not limited to the specific device configuration shown in the above-described embodiment. That is, for example, the vehicle 1 to which the present invention is applied is not limited to a four-wheel vehicle. Specifically, the vehicle 1 may be a three-wheel vehicle, or a six-wheel or eight-wheel vehicle such as a cargo truck. The type of the vehicle 1 may be a vehicle equipped only with an internal combustion engine, an electric vehicle or a fuel cell vehicle not equipped with an internal combustion engine, or a so-called hybrid vehicle. The shape and structure of the vehicle body 2 are not limited to a box shape, that is, a substantially rectangular shape in plan view.

[0036] The present invention can also be suitably applied even when an occupant protection device 11 other than the frontal collision protection device or a pedestrian protection device is mounted.

[0037] As described in the above embodiment, by using the side sensor 13, it is possible to detect a frontal collision and activate the occupant protection device 11 for frontal collision. Therefore, the front sensor 12 can be omitted. However, from the viewpoint of determining a typical frontal collision earlier and from the viewpoint of redundancy, the front sensor 12 and the frontal collision determination using the same can be provided in parallel with the collision determination using the side sensor 13 in the above embodiment. The same applies to the main sensor 14, which can be omitted from the viewpoint of enabling the implementation of the present invention at least, but can be used in combination. Further, by providing a sensor for safing determination in the electronic control device 15, which is an airbag ECU, redundancy of the safing determination may be achieved.

[0038] All or part of the electronic control device 15 may be configured to include a digital circuit capable of performing the above operations, for example, a configuration including an ASIC or an FPGA. ASIC is an abbreviation for Application Specific Integrated Circuit. FPGA is an abbreviation for Field Programmable Gate Array. That is, in the electronic control device 15, the in-vehicle microcomputer part and the digital circuit part can coexist.

[0039] As described above, each of the above functional configurations and methods may be implemented by a dedicated computer provided by configuring a processor and a memory programmed to execute one or more functions embodied by a computer program. Alternatively, each of the above functional configurations and methods may be implemented by a dedicated computer provided by configuring a processor with one or more dedicated hardware logic circuits. Alternatively, each of the above functional configurations and methods may be implemented by one or more dedicated computers configured by a combination of a processor and a memory programmed to execute one or more functions and a processor configured by one or more hardware logic circuits. Further, the computer program may be stored in a non-transitory tangible storage medium readable by a computer as instructions executable by the computer. That is, each of the above functional configurations and methods may also be represented as a computer program including procedures for realizing the same, or as a non-transitory tangible storage medium storing the program.

[0040] A configuration that determines an asymmetric collision based on the output of the main sensor 14, etc. In some cases, an asymmetric collision can be determined while a left-right collision cannot be determined. In this case, it is effective to sensitize sensors that are not malfunctioning regardless of whether they are on the collision side so that the occupant protection device 11 can be deployed when a relatively large impact input is applied to the vehicle body 2. Therefore, when the asymmetric collision determination unit 156 determines an asymmetric collision, the threshold setting unit 154 may be configured to execute a sensitization process regardless of whether the non-faulty sensor is a collision-side sensor. FIG. 8 is a flowchart corresponding to such an aspect. That is, the flowchart of FIG. 8 corresponds to the one in which step 706 in FIG. 7 is omitted. Specifically, when it is not an asymmetric collision (i.e., step 705 = NO), the electronic control unit 15 executes the process of step 704. On the other hand, when it is an asymmetric collision (i.e., step 705 = YES), the electronic control unit 15 executes the process of step 807. In step 807, the electronic control unit 15 executes a sensitization process. That is, the electronic control unit 15 sets the safing determination threshold corresponding to the non-faulty sensor among the left-side determination logic 153d and the right-side determination logic 153e in the safing determination logic 153b to a low threshold regardless of whether it is a collision-side sensor. After executing the sensitization process, in step 808, the electronic control unit 15 determines whether a predetermined time has elapsed since the sensitization process was executed. Before the predetermined time has elapsed (i.e., step 808 = NO), the electronic control unit 15 maintains the low threshold setting state by the sensitization process. On the other hand, when the predetermined time has elapsed (i.e., step 808 = YES), the electronic control unit 15 resets the low threshold setting state by the sensitization process and sets the safing determination threshold corresponding to the non-faulty sensor to the normal threshold.

[0041] The elements constituting the above-described embodiments are not necessarily essential, except in cases where it is explicitly stated that they are particularly essential or where they are considered to be clearly essential in principle. Also, when numerical values such as the number, quantity, range, etc. of components are mentioned, the present invention is not limited to those specific numerical values, except in cases where it is explicitly stated that they are particularly essential or where they are clearly limited to specific numerical values in principle. Similarly, when the shape, direction, positional relationship, etc. of components are mentioned, the present invention is not limited to those shapes, directions, positional relationships, etc., except in cases where it is explicitly stated that they are particularly essential or where they are clearly limited to specific shapes, directions, positional relationships, etc. in principle.

[0042] The modification examples are not limited to the above examples. That is, a part of one embodiment and a part of another embodiment can be combined with each other. Also, a plurality of modification examples can be combined with each other. Furthermore, all or part of the above embodiments and all or part of the modification examples can be combined with each other.

Description of Reference Numerals

[0043] 1 Vehicle 2 Vehicle Body 13 Side Sensor 13L Left Side Sensor 13R Right Side Sensor 14 Main Sensor 15 Electronic Control Unit (Collision Detection Device) 151 First Acceleration Acquisition Unit 152 Second Acceleration Acquisition Unit 153 Front Collision Determination Unit

Claims

1. A collision detection device (15) configured to detect a frontal collision of a vehicle (1), comprising: A left side sensor (13L), which is a biaxial acceleration sensor provided on the left side of the vehicle body (2) of the vehicle and detects the longitudinal acceleration and the lateral acceleration, and a right side sensor (13R), which is a biaxial acceleration sensor provided on the right side of the vehicle body and detects the longitudinal acceleration and the lateral acceleration, a first acceleration acquisition unit (151) that acquires the longitudinal acceleration output from the left side sensor and the right side sensor; A second acceleration acquisition unit (152) that acquires the longitudinal acceleration output from a main sensor (14), which is an acceleration sensor different from the left side sensor and the right side sensor and detects the longitudinal acceleration; A frontal collision determination unit (153) that determines the occurrence of the frontal collision based on a safing determination based on the longitudinal acceleration acquired by the first acceleration acquisition unit and a main determination based on the longitudinal acceleration acquired by the second acceleration acquisition unit; A collision detection device comprising the above.

2. Further comprising a threshold setting unit (154) that sets a safing determination threshold, which is a threshold for the safing determination in the frontal collision determination unit; When the longitudinal acceleration detected by the left side sensor or the right side sensor exceeds the safing determination threshold, the frontal collision determination unit makes the safing determination indicating that the frontal collision has occurred; When one of the left side sensor and the right side sensor, which is a first side sensor, malfunctions and the other, which is a second side sensor, does not malfunction, the threshold setting unit executes a sensitization process of setting the safing determination threshold for the longitudinal acceleration detected by the second side sensor to be lower than that when both the left side sensor and the right side sensor do not malfunction; The collision detection device according to claim 1.

3. Further comprising an asymmetric collision determination unit (156) that determines that the frontal collision is an asymmetric collision; When the asymmetric collision determination unit determines the asymmetric collision, the threshold setting unit executes the sensitization process; The collision detection device according to claim 2.

4. When the asymmetric collision determination unit determines the asymmetric collision and the first side sensor is on the collision side, the threshold setting unit executes the sensitization process; The collision detection device according to claim 3.

5. After the sensitization process is executed, when a predetermined time has elapsed, the threshold setting unit resets the sensitization process. The collision detection device according to any one of claims 2 to 4.

6. A collision detection program executed by a collision detection device (15) configured to detect a frontal collision of a vehicle (1), The process executed by the collision detection device is a process of acquiring the longitudinal acceleration output from a left side sensor (13L) which is a biaxial acceleration sensor provided on the left side portion of the vehicle body (2) of the vehicle and detecting the longitudinal acceleration and the lateral acceleration, and a right side sensor (13R) which is a biaxial acceleration sensor provided on the right side portion of the vehicle body and detecting the longitudinal acceleration and the lateral acceleration; a process of acquiring the longitudinal acceleration output from a main sensor (14) which is an acceleration sensor different from the left side sensor and the right side sensor and detecting the longitudinal acceleration; a process of determining the occurrence of the frontal collision based on a safing determination based on the acquired longitudinal acceleration and a main determination based on the acquired longitudinal acceleration; A collision detection program including the above.

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