Impact determination device

Abstract

To provide an impact determination device capable of more appropriately determining an impact on a vehicle caused by an object, as compared with a case where a threshold is set only on the basis of detection results of an acceleration sensor.SOLUTION: An impact determination device 100 comprises: an internal sensor 1 that includes an acceleration sensor which detects acceleration including each component in the front-rear direction and left-right direction of the own vehicle 50; an external sensor 2 which detects objects in the surroundings of the own vehicle 50; a threshold setting unit 12 which sets a threshold for determining an impact by an object on the own vehicle 50; and an impact determination unit 13 which determines an impact when the acceleration for each component is equal to or greater than the threshold. The threshold setting unit 12 recognizes an impact mode of the object on the own vehicle 50 on the basis of detection results of the external sensor 2, and sets the threshold for each component of acceleration in accordance with the impact mode.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to an impact determination device. [Background technology]

[0002] Conventionally, there is known a device that detects the acceleration of a vehicle in the forward / backward and left / right directions, and determines the collision type of the vehicle by comparing the detected acceleration with a collision type determination threshold value that is stored in advance as a two-dimensional map (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-220743 Summary of the Invention [Problem to be solved by the invention]

[0004] In a device that determines whether a vehicle has been impacted or hit by an object based on a comparison between a threshold value and detected values ​​of longitudinal acceleration in the longitudinal direction of the vehicle and lateral acceleration in the lateral direction of the vehicle, studies have been conducted to optimize the relationship between the acceleration and the threshold value, taking into account the type of collision between the vehicle and the object. However, in the above-mentioned conventional technology, the type of collision is determined solely by comparing the acceleration with the threshold value, and therefore there is room for improvement from a different perspective. [Means for solving the problem]

[0005] An impact determination device according to one aspect of the present disclosure includes an acceleration sensor that detects acceleration including components in the longitudinal and lateral directions of the vehicle, an external sensor that detects objects around the vehicle, a threshold setting unit that sets a threshold for determining an impact caused by an object on the vehicle, and an impact determination unit that determines an impact when the acceleration for each component is equal to or greater than the threshold, and the threshold setting unit recognizes the type of impact of the object on the vehicle based on the detection results of the external sensor, and sets a threshold for each acceleration component according to the type of impact.

[0006] In an impact determination device according to an aspect of the present disclosure, a threshold setting unit recognizes the type of impact of an object on a vehicle based on detection results from an external sensor. The threshold is set for each acceleration component according to the type of impact. This allows the threshold to be set taking into account the type of impact based on the detection results from the external sensor, making it possible to more appropriately determine an impact by an object on a vehicle compared to, for example, a case in which the threshold is set taking into account the type of impact recognized only based on detection results from an acceleration sensor.

[0007] In one embodiment, the threshold setting unit may recognize an offset collision of an object with the vehicle as the impact type, and set a threshold for each acceleration component according to an offset amount of the offset collision. In this case, since the threshold is set for each acceleration component according to the offset amount, it is possible to improve the accuracy of determining an impact caused by an object with the vehicle. [Effects of the Invention]

[0008] According to an impact determination device according to an aspect of the present disclosure, it is possible to more appropriately determine an impact caused by an object on a vehicle compared to a case where a threshold value is set based solely on the detection result of an acceleration sensor, for example. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a block diagram showing a vehicle including an impact determination device according to an embodiment; [Figure 2] 1A is a diagram showing an example of an acceleration sensor mounted on a vehicle, and FIG. 1B is a diagram showing another example of an acceleration sensor mounted on a vehicle. [Figure 3] 1A is a diagram showing an example of an impact form, FIG. 1B is a diagram showing another example of an impact form, and FIG. 1C is a diagram showing another example of an impact form. [Figure 4] 1A is a diagram showing an example of a time series graph of acceleration, and FIG. 1B is a diagram showing an example of acceleration trajectories and thresholds on a two-dimensional plane corresponding to each component of acceleration in FIG. [Figure 5]1A is a diagram showing an example of a time series graph of acceleration without a phase difference, and FIG. 1B is a diagram showing an example of a locus and threshold value obtained by plotting the acceleration of FIG. 1A on a two-dimensional plane. [Figure 6] 1A is a diagram showing an example of a time series graph of acceleration with a phase difference, and FIG. 1B is a diagram showing an example of a locus and threshold value obtained by plotting the acceleration of FIG. 1A on a two-dimensional plane. [Figure 7] 1A is a diagram showing another example of a time series graph of acceleration with a phase difference, and FIG. 1B is a diagram showing an example of a locus and threshold value obtained by plotting the acceleration of FIG. 1A on a two-dimensional plane. [Figure 8] 2A is a flowchart showing an example of processing by the impact determination ECU of Fig. 1. FIG.2B is a flowchart showing an example of processing for recognizing the impact type and setting a threshold value of FIG.2A. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0011] FIG. 1 is a block diagram showing a vehicle including an impact determination device according to one embodiment. FIG. 1 shows a host vehicle (vehicle) 50 equipped with an impact determination device 100. The impact determination device 100 is a device for determining an impact caused by an object on the host vehicle 50 by detecting an impact using two-axis acceleration. The host vehicle 50 is, for example, a passenger car. The object is, for example, another vehicle such as a passenger car traveling around the host vehicle 50. The other vehicle is not limited to a passenger car. The object is not limited to another vehicle.

[0012] The "impact on the vehicle 50 caused by an object" refers to, for example, a collision between the vehicle 50 and an object. The "determination of an impact" in the present disclosure is not limited to determining whether or not a collision has occurred. The impact determination device 100 here is, for example, part of a system that activates an airbag when an impact is determined.

[0013] As shown in FIG. 1, the impact determination device 100 includes an internal sensor 1, an external sensor 2, an airbag actuator 3, and an impact determination ECU (Electronic Control Unit) .

[0014] The impact determination ECU 10 is an electronic control unit having a central processing unit (CPU) and a memory unit. The memory unit is composed of, for example, a read-only memory (ROM), a random access memory (RAM), and an electrically erasable programmable read-only memory (EEPROM). The impact determination ECU 10 realizes various functions by, for example, executing programs stored in the memory unit by the CPU. The impact determination ECU 10 may be composed of multiple electronic units.

[0015] The internal sensor 1 is a detection device that detects the traveling state of the host vehicle 50. The internal sensor 1 includes an acceleration sensor. The acceleration sensor is a detector that detects the acceleration of the host vehicle 50. The acceleration sensor transmits detected acceleration information to the impact determination ECU 10. The internal sensor 1 may include a vehicle speed sensor and a yaw rate sensor.

[0016] The acceleration sensor of the internal sensor 1 detects acceleration including components in the longitudinal and lateral directions of the host vehicle 50. FIG. 2(a) is a diagram showing an example of an acceleration sensor installation. The acceleration sensor here has a two-axis sensor built into one housing, taking into consideration, for example, a reduction in the number of sensors, a reduction in harnesses, and increased flexibility in installation layout. In the acceleration sensor of the internal sensor 1, for example, the longitudinal direction of the host vehicle 50 (the direction of vehicle travel) is assigned as the X axis, and the lateral direction of the host vehicle 50 (the left-right direction perpendicular to the direction of vehicle travel) is assigned as the Y axis. The acceleration sensor of the internal sensor 1 detects the X-axis acceleration in the longitudinal direction of the host vehicle 50 and the Y-axis acceleration in the lateral direction of the host vehicle 50.

[0017] The acceleration sensor of the internal sensor 1 is not limited to a sensor having a two-axis sensor built into a single housing. As shown in Fig. 2(b) of the vehicle 50A, acceleration sensors 1a and 1b each having a one-axis sensor built into a single housing may be arranged close to each other. The acceleration information of each of the acceleration sensors 1a and 1b on one axis may be combined and treated as substantially two-axis acceleration information.

[0018] The external sensor 2 is a detection device that detects objects around the host vehicle 50. The external sensor 2 includes at least one of a camera and a radar sensor. The camera is an imaging device that captures images of the external situation of the host vehicle 50. The camera is provided, for example, on the back side of the windshield of the host vehicle 50, and captures images in front of the host vehicle 50. The camera transmits the captured images related to the external situation of the host vehicle 50 to the impact determination ECU 10. The radar sensor is a detection device that detects objects around the host vehicle 50 using radio waves (for example, millimeter waves) or light. The radar sensor includes, for example, millimeter wave radar or LiDAR (Light Detection and Ranging). The radar sensor transmits information about the detected objects to the impact determination ECU 10.

[0019] The airbag actuator 3 is an actuator for operating an airbag device (not shown). The airbag actuator 3 receives an inflator control signal from the impact determination device 100 under a predetermined condition, such as when the host vehicle 50 is hit by a collision. When the airbag actuator 3 receives the inflator control signal, it operates to inflate the airbag device. The inflator control signal is a signal that commands the airbag actuator 3 to operate.

[0020] Next, a description will be given of the functional configuration of the impact determination ECU 10. The impact determination ECU 10 includes an information recognition unit 11, a threshold setting unit 12, and an impact determination unit 13.

[0021] The information recognition unit 11 recognizes the traveling state of the host vehicle 50 based on the detection result of the internal sensor 1. The traveling state includes the acceleration of the host vehicle 50. The information recognition unit 11 recognizes the two-axial acceleration of the host vehicle 50 based on the acceleration information of the acceleration sensor. The information recognition unit 11 recognizes the acceleration including each component in the forward / backward direction and the left / right direction of the host vehicle 50 based on the detection result of the internal sensor 1.

[0022] The information recognition unit 11 recognizes the external environment of the vehicle 50 based on the detection results of the external sensor 2. The external environment includes the relative position, relative speed, and movement direction of surrounding objects relative to the vehicle 50. The external environment may also include information on the types of objects, such as other vehicles, pedestrians, and bicycles.

[0023] The threshold setting unit 12 sets an acceleration threshold (threshold) for determining an impact caused by an object on the host vehicle 50. The acceleration threshold is a threshold for each component of acceleration for determining an impact caused by an object on the host vehicle 50. The acceleration threshold includes a threshold for an X-axis acceleration in the front-rear direction of the host vehicle 50 and a threshold for a Y-axis acceleration in the left-right direction of the host vehicle 50.

[0024] The threshold setting unit 12 recognizes the type of impact of an object on the host vehicle 50 based on the detection results of the external sensor 2. The impact type refers to the type of force applied to the host vehicle 50 when the object hits the host vehicle 50, depending on how the object hits the host vehicle 50. The magnitude and direction of the force may differ depending on the impact type. The force applied to the host vehicle 50 here may refer to the force at the position where the host vehicle 50 and the object hit each other.

[0025] The impact type may be a collision type in which an object (e.g., another vehicle, a pole, a wall, etc.) collides with the host vehicle 50. Collision types include, for example, a head-on collision, an oblique collision, an offset collision, etc. A head-on collision is a collision in which an object collides with the front of the host vehicle 50 in a manner that faces the traveling direction of the host vehicle 50. A head-on collision includes a head-on collision. As shown in FIG. 3(a), the collision type may be a head-on collision when the angle formed by the traveling direction of the other vehicle 60 with respect to the traveling direction of the host vehicle 50 is less than a predetermined value. As shown in FIG. 3(b), the collision type may be a head-on collision when the amount of lateral deviation (offset amount) of the other vehicle 62 with respect to the traveling direction of the host vehicle 50 is less than a predetermined value. The offset amount may be, for example, the amount of lateral deviation of the center line of the front-to-rear direction of the other vehicle 62 with respect to the center line of the front-to-rear direction of the host vehicle 50.

[0026] An oblique collision is a type of collision in which the traveling direction of an object forms an angle of a predetermined value or more with respect to the traveling direction of the host vehicle 50. As shown in Fig. 3(a), when the angle formed by the traveling direction of the other vehicle 61 with respect to the traveling direction of the host vehicle 50 is a predetermined value or more, the collision type may be an oblique collision.

[0027] An offset collision is a type of collision in which an object is displaced left or right relative to the traveling direction of the host vehicle 50. As shown in Fig. 3(b), when the offset amount of the other vehicle 63 relative to the traveling direction of the host vehicle 50 is equal to or greater than a predetermined value, the collision type may be an offset collision.

[0028] 3(c), even when other vehicles 64, 65 collide with the host vehicle 50 at the same position, the collision type may be different. For example, if the offset amount of the other vehicle 64 is less than a predetermined value, the collision type in which the other vehicle 64 collides with the host vehicle 50 may be an oblique collision. If the offset amount of the other vehicle 65 is equal to or greater than a predetermined value, the collision type in which the other vehicle 65 collides with the host vehicle 50 may be an offset collision.

[0029] The threshold setting unit 12 sets an acceleration threshold for each acceleration component according to the impact mode. The acceleration threshold can be set by performing simulations or collision tests in advance and adapting it to the mode in which a force applied to the host vehicle 50 when an object hits the host vehicle 50 propagates along the body of the host vehicle 50 to the internal sensor 1.

[0030] The impact determination unit 13 determines that an impact has occurred when the acceleration for each acceleration component is equal to or greater than an acceleration threshold value. For example, the impact determination unit 13 compares the recognized acceleration of the vehicle 50 with a set acceleration threshold value for each component.

[0031] For example, the impact determination unit 13 compares the longitudinal component of the recognized acceleration with the longitudinal component of a set acceleration threshold. The impact determination unit 13 compares the lateral component of the recognized acceleration with the lateral component of a set acceleration threshold. The impact determination unit 13 determines an impact when the acceleration is equal to or greater than the acceleration threshold for both the longitudinal and lateral components. The impact determination unit 13 does not determine an impact when the acceleration is less than the acceleration threshold for either the longitudinal or lateral component.

[0032] The setting of the acceleration threshold by the threshold setting unit 12 will be described in more detail. Fig. 4(a) is a diagram showing an example of a time series graph of acceleration. Fig. 4(a) illustrates an example of X-axis acceleration and Y-axis acceleration corresponding to a force when an object hits the host vehicle 50 and the force applied to the host vehicle 50 propagates along the body of the host vehicle 50 to the acceleration sensor.

[0033] In FIG. 4(a), dashed lines (1) to (5) are attached to some of the maximum and minimum values ​​of the X-axis acceleration. The dashed lines (1) to (5) may be offset from the positions of the maximum and minimum values ​​of the Y-axis acceleration on the Y-axis acceleration curve. That is, there may be a phase difference between the waveform of the X-axis acceleration and the waveform of the Y-axis acceleration. This phase difference may occur in various ways depending on, for example, differences in the structure of the vehicle body (platform) of the vehicle 50, differences in the equipment of the vehicle 50, the installation position of the acceleration sensor (such as a deviation from the center of the vehicle in the lateral direction), the type of collision, etc. The structure of the vehicle body of the vehicle 50 may differ depending on the size and intended use of the vehicle 50, etc. As such, the propagation path of the impact force applied to the vehicle 50 to the acceleration sensor may be very complex. In addition to the phase difference, the magnitude of the corresponding peaks in the waveforms of the X-axis acceleration and the Y-axis acceleration detected by the acceleration sensor may differ.

[0034] Taking into consideration such phase differences and differences in peak magnitudes, the threshold setting unit 12 sets the acceleration threshold. Fig. 4(b) is a diagram showing an example of acceleration loci and thresholds on a two-dimensional plane corresponding to each acceleration component in Fig. 4(a).

[0035] For ease of explanation, the acceleration threshold defines a hatched area on the two-dimensional plane in FIG. 4(b). In the example of FIG. 4(b), the hatched area is defined as a convex (inverted T-shaped) area symmetrical about the X-axis on the two-dimensional plane using the coordinates (x1, y1) and (x2, y2) of points P1 and P2 as the acceleration threshold. The acceleration threshold in FIG. 4(b) is a normal threshold TH1. The normal threshold TH1 is an acceleration threshold used, for example, when a head-on collision of another vehicle with the host vehicle 50 is recognized as the impact type, or when the possibility of a collision between the host vehicle 50 and an object is estimated by a known method based on the detection result of the external sensor 2.

[0036] On the two-dimensional plane of Figure 4(b), if the position where the X-axis acceleration and the Y-axis acceleration are plotted is outside the hatched area, it corresponds to the case where the acceleration is equal to or greater than the acceleration threshold for both the front-rear and left-right components, and an impact is determined. If the position where the X-axis acceleration and the Y-axis acceleration are plotted is within the hatched area, it corresponds to the case where the acceleration is less than the acceleration threshold for either the front-rear or left-right component, and an impact is not determined.

[0037] In the host vehicle 50, an airbag is activated when an impact is detected, so the acceleration threshold value is set so as to prevent erroneous detection of an impact. The hatched area in Fig. 4(b) is defined so that the position where the X-axis acceleration and Y-axis acceleration are plotted falls within the hatched area, depending on the impact caused by vibrations while the host vehicle 50 is traveling with normal acceleration / deceleration and steering, input from an uneven road surface, a minor collision with an object, etc. Note that, in consideration of reducing the calculation load on the impact detection ECU 10, the acceleration threshold value may be set so as to define a hatched area whose outer edge is linear.

[0038] Incidentally, in Figure 4(b), positions (1) to (5) are shown along the trajectory of the white arrow. Positions (1) to (5) in Figure 4(b) correspond to the positions obtained by plotting the X-axis acceleration and the Y-axis acceleration on a two-dimensional plane at the times indicated by dashed lines (1) to (5) in Figure 4(a). If there is a phase difference between the X-axis acceleration waveform and the Y-axis acceleration waveform as shown in Figure 4(a), the positions obtained by plotting the X-axis acceleration and the Y-axis acceleration may move in a complex manner on the two-dimensional plane, as shown by the trajectory of the white arrow in Figure 4(b).

[0039] FIG. 5(a) shows an example of a time series graph of acceleration without a phase difference. FIG. 5(b) shows an example of a trajectory and threshold values ​​obtained by plotting the acceleration of FIG. 5(a) on a two-dimensional plane. As shown in FIG. 5(a), if the phase difference between the X-axis acceleration waveform and the Y-axis acceleration waveform (the difference in the time of the peaks indicated by stars in the figure) is within a predetermined time difference (almost simultaneous), as in the case of a head-on impact, the plotted positions of the X-axis acceleration and the Y-axis acceleration (tips of white arrows) are outside the hatched area defined by the normal threshold value TH1, as shown in FIG. 5(b), and an impact can be appropriately determined. The hatched area defined by the normal threshold value TH1 may be defined by multiple straight lines that are approximately perpendicular to the X-axis or Y-axis on the two-dimensional plane.

[0040] However, due to the phase difference and the difference in peak magnitude between the X-axis acceleration waveform and the Y-axis acceleration waveform, the position where the X-axis acceleration and the Y-axis acceleration are plotted may not be outside the hatched area as in the example of Figure 5, and an impact may not be erroneously determined.

[0041] FIG. 6(a) is a diagram showing an example of a time-series graph of acceleration with a phase difference. FIG. 6(b) is a diagram showing an example of a trajectory and threshold value obtained by plotting the acceleration of FIG. 6(a) on a two-dimensional plane. For example, if the impact type is an oblique collision, or if the impact type is an oblique collision with an offset collision, the acceleration waveform shown in FIG. 6(a) may be obtained. In this case, if a phase difference exists beyond a predetermined time difference such that the Y-axis acceleration waveform peaks earlier than the X-axis acceleration waveform, the acceleration threshold value may be set to a first correction threshold value TH2 using the coordinates (x1, y3) of point P3. In this case, the hatched area defined by the first correction threshold value TH2 includes a portion defined by inclined straight lines relative to the X-axis and Y-axis on the two-dimensional plane.

[0042] The acceleration threshold may be set to include the value of coordinate y3. y3 has an absolute value smaller than y1. The value of coordinate y3 may be set by, for example, calculating the slope of a sloping line from the phase difference and the difference in peak magnitude between the X-axis acceleration waveform and the Y-axis acceleration waveform based on simulations or crash test results for oblique impacts. The sloping line may include multiple break points or may be set asymmetrically with respect to the X-axis.

[0043] As a result, as shown in FIG. 6(b), the position where the X-axis acceleration and Y-axis acceleration are plotted (the tip of the white arrow) is outside the hatched area defined by the first correction threshold TH2, and an impact can be appropriately determined.

[0044] The threshold setting unit 12 may recognize an offset collision of another vehicle with the host vehicle 50 as the impact type and set an acceleration threshold for each acceleration component according to the offset amount of the offset collision. FIG. 7(a) illustrates another example of a time-series graph of acceleration with a phase difference. FIG. 7(b) illustrates an example of a trajectory and threshold value obtained by plotting the acceleration of FIG. 7(a) on a two-dimensional plane. For example, if the impact type is an offset collision with a large offset amount, or an offset collision that is not an oblique collision, the acceleration waveform shown in FIG. 7(a) may be obtained. In this case, if a phase difference exists beyond a predetermined time difference such that the X-axis acceleration waveform peaks earlier than the Y-axis acceleration waveform, the acceleration threshold may be set to a second correction threshold TH3 using the coordinates (x1, y4) and (x2, y4) of points P4 and P5. In this case, the hatched area defined by the second correction threshold TH3 does not need to include a portion defined by inclined straight lines relative to the X-axis and Y-axis on the two-dimensional plane.

[0045] The acceleration threshold may be set to include the value of coordinate y4. y4 may have an absolute value smaller than y1. y4 may have an absolute value larger than y3. The value of coordinate y4 may be set by calculating the difference between y1 and y4 from the phase difference and the difference in peak magnitude between the X-axis acceleration waveform and the Y-axis acceleration waveform, based on, for example, simulation or crash test results when the impact type is an offset collision.

[0046] As a result, as shown in FIG. 7(b), the locus (white arrow) of the positions where the X-axis acceleration and Y-axis acceleration are plotted passes outside the hatched area defined by the second correction threshold TH3, and the impact can be appropriately determined.

[0047] Incidentally, the acceleration threshold may be updated by an update process from a server SV provided in the center C. The transmitter 20 of the impact determination device 100 and the receiver 30 of the center C are configured to be able to communicate via known wireless communication. The server SV may be a general-purpose computer. For example, when knowledge that can further improve safety is obtained, update information of the acceleration threshold based on such knowledge is stored in the memory 40 of the server SV. The update unit 41 can update the acceleration threshold of the host vehicle 50 using the update information from the memory 40. However, "updating" here means updating the acceleration threshold when the preset acceleration threshold of the host vehicle 50 satisfies certification tests such as crash safety at the time of initial sale, and updating the acceleration threshold does not impair the certification test results at all, and it can be demonstrated that updating the acceleration threshold improves safety.

[0048] [Operation of impact detection device] Next, the operation of the impact determination device 100 will be described with reference to the drawings. Fig. 8(a) is a flowchart showing an example of the processing of the impact determination ECU of Fig. 1. Fig. 8(b) is a flowchart showing an example of the processing of impact type recognition and threshold setting of Fig. 8(a). The processing of Figs. 8(a) and (b) may be executed when the vehicle speed of the host vehicle is equal to or greater than a predetermined vehicle speed threshold.

[0049] 8(a), in step S11, the impact determination ECU 10 of the impact determination device 100 recognizes acceleration including components in the front-rear direction and the left-right direction using the information recognition unit 11. The information recognition unit 11 recognizes acceleration including components in the front-rear direction and the left-right direction of the host vehicle 50 based on the detection result of the internal sensor 1.

[0050] In step S12, the impact determination ECU 10 recognizes the impact type and sets an acceleration threshold value using the threshold value setting unit 12. The threshold value setting unit 12 recognizes the type of impact of another vehicle on the host vehicle 50 based on the detection results of the external sensor 2. The threshold value setting unit 12 sets an acceleration threshold value for each recognized acceleration component according to the impact type. The threshold value setting unit 12 sets a longitudinal acceleration threshold value for the longitudinal component of the recognized acceleration according to the impact type. The threshold value setting unit 12 sets a lateral acceleration threshold value for the lateral component of the recognized acceleration according to the impact type. As a specific process of S12, the impact determination ECU 10 may perform, for example, the process shown in FIG. 8(b).

[0051] 8(b), in step S21, the impact determination ECU 10 determines, using the threshold setting unit 12, whether or not the offset amount is less than the offset threshold. The threshold setting unit 12 recognizes the offset amount of the other vehicle relative to the host vehicle 50 based on, for example, the detection result of the external sensor 2, and compares the offset amount with the offset threshold. If the offset amount is less than the offset threshold, the threshold setting unit 12 may recognize the impact type as a head-on collision of the other vehicle with the host vehicle 50. If the offset amount is equal to or greater than the offset threshold, the threshold setting unit 12 may recognize the impact type as an offset collision of the other vehicle with the host vehicle 50.

[0052] If it is determined that the offset amount is less than the offset threshold (S21: YES), in step S22, the impact determination ECU 10 sets a normal threshold for each acceleration component using the threshold setting unit 12. The threshold setting unit 12 reads x1, y1, x2, y2, etc. for each acceleration component, plots P1 and P2 on a two-dimensional plane, and sets a normal threshold TH1 that passes through P1 and P2 as the acceleration threshold, as shown in Figures 4 and 5, for example. Note that if the offset amount is less than the offset threshold and the detection result of the external sensor 2 indicates that the possibility of a collision between the host vehicle 50 and an object is low using a known method, the threshold setting unit 12 may set the normal threshold TH1 as the acceleration threshold without particularly recognizing the impact type. Thereafter, the impact determination ECU 10 ends the current process of Figure 8(b) and returns to the process of S13 of Figure 8(a).

[0053] If it is determined that the offset amount is equal to or greater than the offset threshold (S21: NO), in step S23, the impact determination ECU 10 determines, using the threshold setting unit 12, whether or not the angle is less than the angle threshold. The threshold setting unit 12 recognizes the angle of the other vehicle relative to the host vehicle 50 based on the detection result of the external sensor 2, and compares the angle with the angle threshold. If the angle is less than the angle threshold, the threshold setting unit 12 may recognize an offset collision that is not an oblique collision as the impact type. If the angle amount is equal to or greater than the angle threshold, the threshold setting unit 12 may recognize an oblique and offset collision as the impact type.

[0054] If it is determined that the angle is less than the angle threshold (S23: YES), in step S24, the impact determination ECU 10 sets a second corrected threshold for each acceleration component using the threshold setting unit 12. For example, as shown in FIG. 7, the threshold setting unit 12 may read x1, y4, x2, y4, etc. for each acceleration component, plot P2, P4, and P5 on a two-dimensional plane, and set the second corrected threshold TH3 that passes through P2, P4, and P5 as the acceleration threshold. Thereafter, the impact determination ECU 10 ends the current process of FIG. 8(b) and returns to the process of S13 of FIG. 8(a).

[0055] If it is determined that the angle is equal to or greater than the angle threshold value (S23: NO), in step S25, the impact determination ECU 10 sets a first corrected threshold value for each acceleration component using the threshold value setting unit 12. For example, as shown in FIG. 6, the threshold value setting unit 12 may read x1, y3, x2, y2, etc. for each acceleration component, plot P2 and P3 on a two-dimensional plane, and set the first corrected threshold value TH2 that passes through P2 and P3 as the acceleration threshold value. Thereafter, the impact determination ECU 10 ends the current process of FIG. 8(b) and returns to the process of S13 of FIG. 8(a).

[0056] Returning to FIG. 8(a), in step S13, the impact determination ECU 10 determines, via the impact determination unit 13, whether the acceleration is equal to or greater than the acceleration threshold. The impact determination unit 13, for example, compares the recognized acceleration of the host vehicle 50 with the acceleration threshold set in S12. The impact determination unit 13 compares the longitudinal component of the recognized acceleration with the longitudinal component of the set acceleration threshold. The impact determination unit 13 compares the lateral component of the recognized acceleration with the lateral component of the set acceleration threshold. If the acceleration is equal to or greater than the acceleration threshold for both the longitudinal and lateral components, the impact determination unit 13 determines "YES" in the process of step S13. If the acceleration is less than the acceleration threshold for either the longitudinal or lateral component, the impact determination unit 13 determines "NO" in the process of step S13.

[0057] In step S14, the impact determination ECU 10 determines whether an impact has occurred using the impact determination unit 13. In step S14, the impact determination unit 13 determines that an impact of a certain magnitude or greater has occurred on the host vehicle 50 by another vehicle. The impact determination ECU 10 may transmit an inflator control signal to the airbag actuator 3 to deploy the airbag device. Thereafter, the impact determination ECU 10 ends the current processing of FIG. 8(a).

[0058] In the impact determination device 100 described above, the impact determination ECU 10 uses the threshold setting unit 12 to recognize the type of impact of another vehicle on the host vehicle 50 based on the detection results of the external sensor 2. The acceleration threshold is set for each acceleration component according to the impact type. This allows the acceleration threshold to be set taking into account the impact type based on the detection results of the external sensor 2, making it possible to more appropriately determine an impact by another vehicle on the host vehicle 50 compared to, for example, a case in which the acceleration threshold is set taking into account the impact type recognized only based on the detection results of the acceleration sensor. As a result, it is possible to realize a system that uses impact determination results at low cost while minimizing degradation of detection performance.

[0059] In the impact determination device 100, the threshold setting unit 12 recognizes an offset collision of another vehicle with the host vehicle 50 as the type of impact, and sets an acceleration threshold for each acceleration component according to the offset amount of the offset collision. As a result, the acceleration threshold is set for each acceleration component according to the offset amount, which improves the accuracy of determining an impact caused by another vehicle on the host vehicle 50.

[0060] Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments. The present disclosure can be implemented in various forms including the above-described embodiments and various modifications and improvements based on the knowledge of those skilled in the art.

[0061] In the above embodiment, the threshold setting unit 12 sets the acceleration threshold for each acceleration component according to the offset amount of the offset collision and the angle of the other vehicle relative to the host vehicle 50, but this example is not limiting. For example, the threshold setting unit 12 may set the acceleration threshold for each acceleration component according to information such as the type of the other vehicle (that is, the size and weight of the other vehicle), the relative speed of the other vehicle relative to the host vehicle 50, and the speed of the host vehicle 50.

[0062] In the above embodiment, the acceleration threshold is set for each acceleration component according to the offset amount of the offset collision, but this example may be omitted.

[0063] In the above embodiment, an example in which an airbag device is deployed is shown as a system that uses the impact determination result, but this example is not essential. The impact determination device 100 is only required to be able to at least determine the impact. [Explanation of symbols]

[0064] 1...internal sensor (acceleration sensor), 1a, 1b...acceleration sensors, 2...external sensor, 12...threshold value setting unit, 13...impact determination unit, 50...host vehicle (vehicle), 100...impact determination device.

Claims

1. an acceleration sensor that detects acceleration including components in the front-rear direction and the left-right direction of the vehicle; an external sensor for detecting objects around the vehicle; a threshold setting unit that sets a threshold for determining an impact caused by the object on the vehicle; an impact determination unit that determines the impact when the acceleration for each of the components is equal to or greater than the threshold; The threshold setting unit Recognizing the type of impact of the object on the vehicle based on the detection results of the external sensor; an impact determination device that sets the threshold value for each of the components of the acceleration in accordance with the impact type;

2. The threshold setting unit recognize an offset collision of the object with the vehicle as the impact type; The impact determination device according to claim 1 , wherein the threshold value is set for each of the components of the acceleration in accordance with an offset amount of the offset collision.

Images