Control device for protection device

Abstract

To provide a control device for a protection device which can execute safing determination with high accuracy.SOLUTION: A control device for a protection device includes main determination means for determining whether a vehicle and an object collide with each other on the basis of acceleration detected by a first sensor installed on a vehicle, safing determination means for permitting operation of a protection device, when acceleration detected by a second sensor installed at a position different from the first sensor of the vehicle is larger than a threshold, operation determination means for operating the protection device, when it is determined by the main determination means that the vehicle and the object have collided with each other and it is permitted by the safing determination means that the operation of the protection device is permitted, and collision prediction means for predicting whether the vehicle and an object existing around the vehicle collide with each other, on the basis of peripheral information indicating a peripheral situation of the vehicle, wherein the safing determination means sets the threshold to be smaller than a case in which it has been predicted that the vehicle and the object do not collide with each other, when it has been predicted that the vehicle and the object collides with each other.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a control device for a protection device. [Background technology]

[0002] When controlling a protection device such as an airbag for protecting a vehicle occupant, a main judgment is made to detect a vehicle collision, and a safing judgment is made to prevent a malfunction of the protection device (e.g., unnecessary deployment of an airbag, etc.). The main judgment and the safing judgment are generally made based on acceleration detected by an acceleration sensor mounted on the vehicle, and an acceleration sensor for the main judgment and an acceleration sensor for the safing judgment may be provided separately. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-147668 A Summary of the Invention [Problem to be solved by the invention]

[0004] As described above, when the acceleration sensor for the main judgment and the acceleration sensor for the safing judgment are provided separately, there is a possibility that the acceleration used for the safing judgment may not be detected appropriately depending on the collision mode between the vehicle and the object (for example, whether or not it is an offset collision.) For example, when the acceleration sensor for the safing judgment is disposed offset from the center in the vehicle width direction toward the driver's seat and the collision position in the offset collision is on the passenger's seat side, the acceleration used for the safing judgment may be detected as smaller than the actual impact, and the airbag may not be deployed even though the situation is such that the airbag should be deployed.

[0005] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide a control device for a protection device that can perform safing judgment with high accuracy. [Means for solving the problem]

[0006] A control device for a protection device as one embodiment of the present invention is a control device for a protection device for protecting an occupant of a vehicle, and includes a main judgment means for judging whether or not a collision has occurred between the vehicle and an object based on acceleration detected by a first sensor installed in the vehicle, a safing judgment means for permitting operation of the protection device when acceleration detected by a second sensor installed in a position different from the first sensor of the vehicle is greater than a threshold value, an operation judgment means for activating the protection device when the main judgment means judges that a collision has occurred and the safing judgment means permits operation of the protection device, and a collision prediction means for predicting whether or not a collision will occur between the vehicle and an object present in the vicinity of the vehicle based on surrounding information indicating the situation around the vehicle, and the safing judgment means is characterized in that when it is predicted that the vehicle will collide with the object, the threshold value is made smaller than when it is predicted that the vehicle will not collide with the object.

[0007] According to the above configuration, the main determination means and the safing determination means constitute a multiplex system, and when a collision between the vehicle and an object is predicted based on peripheral information, the threshold value for safing determination is changed to a value smaller than the normal value. This allows the protection device to be appropriately operated even in a situation where a low acceleration for safing determination is detected due to the type of collision or the like (for example, an offset collision on the opposite side to the installation position of the second sensor, etc.).

[0008] In the above configuration, the safing determination means may permit the operation of the protection device when a collision between the vehicle and an object is predicted when the second sensor is abnormal.

[0009] According to the above configuration, the protection device can be activated even when an abnormality occurs in the second sensor.

[0010] In addition, in the above configuration, the second sensor may be installed at a position shifted to one side from the center of the vehicle in the width direction, the collision prediction means predicts a collision between the vehicle and an object in an area on the side where the second sensor is not installed, and the safing determination means may set the threshold value smaller when it is predicted that the vehicle will collide with the object in the area on the side where the second sensor is not installed than when it is predicted that the vehicle will not collide with the object.

[0011] According to the above configuration, the protection device can be appropriately operated when an offset collision or the like occurs.

[0012] In the above configuration, the collision prediction means may further predict a collision type of a collision between the vehicle and the object, and the safing determination means may change the threshold value according to the collision type.

[0013] According to the above configuration, the threshold value for safing determination can be optimized according to the type of collision, and the protection device can be appropriately operated. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a top view showing an example of a vehicle equipped with an occupant protection system according to an embodiment. [Diagram 2] FIG. 2 is a block diagram showing an example of a hardware configuration of the occupant protection system according to the embodiment. [Diagram 3] FIG. 3 is a block diagram illustrating an example of a functional configuration of the protection device ECU according to the embodiment. [Figure 4] FIG. 4 is a diagram illustrating an example of a relationship between a collision prediction and a safing threshold according to the embodiment. [Diagram 5] FIG. 5 is a logic circuit diagram showing an example of an operating condition of the protection device according to the embodiment. [Figure 6] FIG. 6 is a flowchart illustrating an example of a process performed by the protection device ECU according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The configuration of the embodiment described below and the actions and effects brought about by the configuration are merely examples, and the present invention is not limited to the following description.

[0016] 1 is a top view showing an example of a vehicle C equipped with an occupant protection system 1 according to an embodiment. The occupant protection system 1 is a system that activates a protection device such as an airbag for protecting an occupant of the vehicle C when the vehicle C crashes.

[0017] The occupant protection system 1 of this embodiment includes a protection device control unit 11, an internal G sensor 12A (an example of a first sensor), a satellite G sensor 12B (an example of a second sensor), and a stereo camera unit 15.

[0018] The protection device control unit 11 is a unit equipped with circuits, devices, etc. that control the operation of protection devices such as airbags mounted on the vehicle C. In this embodiment, the protection device control unit 11 is disposed in the center of the instrument panel in the vehicle width direction. A built-in G sensor 12A is disposed in the protection device control unit 11. The built-in G sensor 12A is an acceleration sensor that detects the acceleration applied to the vehicle C. Note that the installation positions of the protection device control unit 11 and the built-in G sensor 12A are not limited to this.

[0019] The satellite G sensor 12B is an acceleration sensor installed at a position shifted toward the driver's seat from the center in the vehicle width direction of the vehicle C, and in this embodiment, is installed near the right front end portion of the vehicle C. However, the installation position of the satellite G sensor 12B is not limited to this.

[0020] The stereo camera unit 15 is a unit that includes circuits, devices, and the like for acquiring image data (an example of peripheral information) obtained by capturing an image of the area in front of the vehicle C, and for executing processing, etc., for predicting a collision between the vehicle C and an object (e.g., another vehicle, a road structure, a person, etc.) existing in the vicinity of the vehicle C based on the image data. The stereo camera unit 15 is installed, for example, in the center of the upper part of the windshield. Note that the installation position of the stereo camera unit 15 is not limited thereto.

[0021] The protection device control unit 11 of this embodiment controls the operation of protection devices such as airbags based on the acceleration detected by the built-in G sensor 12A, the acceleration detected by the satellite G sensor, and information obtained from the stereo camera unit 15.

[0022] 2 is a block diagram showing an example of a hardware configuration of the passenger protection system 1 according to the embodiment. The passenger protection system 1 illustrated here includes a protection device control unit 11, a satellite G sensor 12B, a stereo camera unit 15, and a protection device 30.

[0023] The stereo camera unit 15 includes a stereo camera 21 and a camera ECU (Electronic Control Unit) 22. The stereo camera 21 is an imaging device that acquires two pieces of image data having a parallax between them through two lenses arranged at a predetermined interval. The camera ECU 22 is an information processing device that is configured using a CPU (Central Processing Unit), an FPGA (Field Programmable Gate Array), an ASIC (Application Specific Integrated Circuit), a memory, etc. Based on the image data acquired by the stereo camera 21, the camera ECU 22 generates a three-dimensional map in which distance information indicating the distance from the vehicle C to an object is added to a two-dimensional map of the imaging range, and generates information regarding an object present in the vicinity of the vehicle C based on the three-dimensional map. The information regarding the object may include information indicating whether or not the vehicle C will collide with the object present in the vicinity of the vehicle C.

[0024] Moreover, the stereo camera unit 15 constitutes a part of an automatic driving system or a driving assistance system of the vehicle C. Information generated by the stereo camera unit 15 (camera ECU 22) is output to a VSC (Vehicle Stability Control) ECU 41 and is used for automatic braking control that automatically controls a brake device 40 that decelerates the vehicle C. Note that the information generated by the stereo camera unit 15 may be used for control other than automatic braking control, such as automatic acceleration / deceleration control and automatic steering control.

[0025] The protection device control unit 11 includes a built-in G sensor 12A and a protection device ECU 13. The protection device ECU 13 is an information processing device configured using a CPU, an FPGA, an ASIC, a memory, etc. The protection device ECU 13 controls the operation of the protection device 30 based on the acceleration G1 detected by the built-in G sensor 12A, the acceleration G2 detected by the satellite G sensor 12B, and information acquired from the stereo camera unit 15.

[0026] The protection device 30 illustrated here includes a D seat airbag 31A, a P seat airbag 31B, a D seat pretensioner 32A, and a P seat pretensioner 32B. The D seat airbag 31A is an airbag installed on the driver's seat side of the front row to protect the driver. The P seat airbag 31B is an airbag installed on the passenger's seat side of the front row to protect the passenger in the passenger seat. The D seat pretensioner 32A is a device that increases the restraining force of the driver's seat seat belt when the D seat airbag 31A is deployed. The P seat pretensioner 32B is a device that increases the restraining force of the passenger's seat seat belt when the P seat airbag 31B is deployed. Note that the protection device 30 is not limited to this.

[0027] 3 is a block diagram showing an example of a functional configuration of the protection device ECU 13 of the embodiment. The protection device ECU 13 of the embodiment includes a main determination unit 101, a safing determination unit 102, an operation determination unit 103, and a collision prediction unit 104. These functional units are configured by cooperation between hardware and software (programs, etc.) constituting the protection device ECU 13. At least one of these functional units may be configured by dedicated hardware (circuits, etc.).

[0028] The main judgment unit 101 performs a main judgment to judge whether or not the vehicle C has collided with an object based on the acceleration G1 detected by the built-in G sensor 12A. The specific method of the main judgment should not be particularly limited, but for example, when the acceleration G1 is greater than a predetermined main threshold, it can be judged that the vehicle C has collided with the object. When it is judged that the vehicle C has collided with the object, the main judgment unit 101 outputs a collision signal.

[0029] The safing determination unit 102 performs a safing determination to determine whether or not to permit operation of the protection device 30 based on the acceleration G2 detected by the satellite G sensor 12B. The safing determination unit 102 permits operation of the protection device 30 when the acceleration G2 is greater than a predetermined safing threshold, and prohibits operation of the protection device 30 when the acceleration G2 is not greater than the safing threshold. The safing determination unit 102 outputs a permission signal when operation of the protection device 30 is permitted by the safing determination.

[0030] The activation judgment unit 103 activates the protection device 30 when the main judgment determines that the vehicle C has collided with an object (a collision signal is output from the main judgment unit 101) and the safing judgment permits activation of the protection device 30 (an authorization signal is output from the safing judgment unit 102).

[0031] The collision prediction unit 104 predicts whether or not the vehicle C will collide with an object present in the vicinity of the vehicle C, based on surrounding information (e.g., image data acquired by the stereo camera 21, etc.) indicating the situation around the vehicle C. Specifically, the prediction of whether or not a collision will occur is performed, for example, by calculating a predicted collision time (TTC: Time To Collision) between the vehicle C and the object, and when the TTC becomes equal to or less than a predetermined threshold, it can be predicted that the vehicle C will collide with the object.

[0032] In the present embodiment, when the collision prediction unit 104 predicts that the vehicle C will collide with an object, the safing determination unit 102 sets the safing threshold to be smaller than when it is predicted that the vehicle C will not collide with the object (normally). As a result, when the collision prediction unit 104 predicts that the vehicle C will collide with an object, the safing threshold becomes smaller than normal, and the operation of the protection device 30 can be permitted even if the acceleration G2 detected by the satellite G sensor 12B is smaller than the value at which operation is permitted in normal times.

[0033] Fig. 4 is a diagram showing an example of the relationship between collision prediction and safing threshold Ts in the embodiment. In the upper part of Fig. 4, a graph showing a time series change in collision prediction by the collision prediction unit 104 is illustrated. In the graph, "ON" indicates a state in which it is predicted that the vehicle C will collide with an object, and "OFF" indicates a state in which it is predicted that the vehicle C will not collide with an object. Here, a case in which the collision prediction changes from "OFF" to "ON" at time t1 is illustrated.

[0034] The lower part of Fig. 4 illustrates a graph showing the time series changes of the acceleration G2 detected by the satellite G sensor 12 and the safing threshold Ts. As shown in the graph, the safing threshold Ts changes from δ to ε at time t1 when the collision prediction is turned "ON". Note that the relationship between δ and ε is ε<δ. The graph also illustrates a situation in which the acceleration G2 increases after the vehicle C collides with an object at time t2, and the acceleration G2 becomes larger than the safing threshold Ts (ε) at time t3. In this case, the operation of the protection device 30 is permitted at time t3.

[0035] As described above, when the collision prediction is "ON", the safing threshold Ts changes to a value ε that is smaller than the value δ in the normal state (when the collision prediction is "OFF"). This makes it possible to appropriately operate the protection device 30 even in a situation where the acceleration G2 for safing judgment is detected as low due to the type of collision or the like (for example, an offset collision on the passenger seat side in this embodiment).

[0036] Furthermore, when the satellite G sensor 12B is abnormal, the safing determination unit 102 may permit the operation of the protection device 30 if the collision prediction unit 104 predicts that the vehicle C will collide with an object. The method of detecting an abnormality in the satellite G sensor 12B may be realized by appropriately utilizing a publicly known or new technology, and it can be determined that an abnormality has occurred, for example, when the value of the acceleration G2 output from the satellite G sensor 12B is fixed at an abnormal value such as 0 or a maximum value, or when the value fluctuates greatly. This allows the protection device 30 to be activated even when the satellite G sensor 12B is abnormal.

[0037] The collision prediction unit 104 may also predict a collision between the vehicle C and an object in an area on the side where the satellite G sensor 12B is not installed (the passenger seat side in this embodiment). In this case, the safing determination unit 102 may set the safing threshold value Ts to be smaller than normal when it is predicted that the vehicle C will collide with an object (such as an offset collision) in an area on the side where the satellite G sensor 12B is not installed. This allows the protection device 30 to be appropriately activated when an offset collision or the like occurs.

[0038] The collision prediction unit 104 may also predict the type of collision between the vehicle C and an object. The type of collision is predicted based on the positional relationship (including the predicted collision position and collision direction) between the object and the vehicle C detected by an external environment recognition means such as the stereo camera 21. The type of collision may be, for example, an offset collision, an underride collision, etc. In this case, the safing determination unit 102 may change the safing threshold Ts according to the type of collision. This makes it possible to optimize the safing threshold Ts according to the type of collision, and to appropriately operate the protection device 30.

[0039] Fig. 5 is a logic circuit diagram showing an example of an operating condition of the protection device 30 of the embodiment. In Fig. 5, a first main judgment, a second main judgment, a first safing judgment, a second safing judgment, and a fail-safe are illustrated.

[0040] The first main determination is a determination whose truth value is "true" when the acceleration G1 detected by the internal G sensor 12A is greater than the threshold value α.

[0041] The second main judgment is a judgment whose truth value is "true" when the acceleration G1 detected by the internal G sensor 12A is greater than the threshold value β and the acceleration G2 detected by the satellite G sensor 12B is greater than the threshold value γ. At this time, a relationship of α>β is established between the threshold value β and the threshold value α used in the first main judgment.

[0042] When at least one of the first main judgment and the second main judgment is "true", the truth value Vm of the main judgment as a whole is "true".

[0043] The first safing judgment is a judgment whose truth value is "true" when the acceleration G2 detected by the satellite G sensor 12B is greater than the threshold value δ. At this time, the relationship γ>>δ is established between the threshold value δ and the threshold value γ used in the second main judgment.

[0044] The second safing determination is a determination whose truth value is "true" when the acceleration G2 detected by the satellite G sensor 12B is greater than the threshold value ε and the collision prediction result by the collision prediction unit 104 is ON. At this time, the relationship δ>ε is established between the threshold value ε and the threshold value δ used in the first safing determination.

[0045] The fail-safe is a judgment whose truth value is "true" when the abnormality judgment of the satellite G sensor 12B is ON (a state in which the satellite G sensor 12B is judged to have an abnormality) and the collision prediction result by the collision prediction unit 104 is ON. At this time, in response to the abnormality judgment of the satellite G sensor 12B being ON, a warning light may be turned on to notify the occupants of the abnormality.

[0046] When at least one of the first safing judgment, the second safing judgment, and the fail-safe is determined to be "true," the truth value Vs of the entire safing judgment is determined to be "true."

[0047] When both the truth value Vm and the truth value Vs are "true", the protection device 30 is activated.

[0048] 6 is a flowchart showing an example of processing by the protection device ECU 13 of the embodiment. In step S101, the main determination unit 101 determines whether or not the acceleration G1 detected by the built-in G sensor 12A is greater than the main threshold value α. If the acceleration G1 is greater than the main threshold value α in step S101 (S101: Yes), the safing determination unit 102 determines whether or not the acceleration G2 detected by the satellite G sensor 12B is greater than the safing threshold value δ in step S102. If the acceleration G2 is greater than the safing threshold value δ in step S102 (S102: Yes), the operation determination unit 103 activates the protection device 30 in step S106.

[0049] In step S102, if the acceleration G2 is not greater than the safing threshold δ (S102: No), in step S103, the collision prediction unit 104 determines whether or not the collision prediction is ON (whether or not the vehicle C will collide with an object) based on the information acquired from the stereo camera unit 15. In step S103, if the collision prediction is not ON (S103: No), the protection device 30 is not activated and this routine ends.

[0050] If the collision prediction is ON in step S103 (S103: Yes), the safing determination unit 102 determines whether the acceleration G2 is greater than the safing threshold ε (ε<δ) in step S104. If the acceleration G2 is greater than the safing threshold ε in step S104 (S104: Yes), the operation determination unit 103 activates the protection device 30 in step S106.

[0051] If the acceleration G2 is not greater than the safing threshold ε in step S104 (S104: No), then in step S105 it is determined whether or not there is an abnormality in the satellite G sensor 12B. If there is an abnormality in the satellite G sensor 12B in step S105 (S105: Yes), then in step S106 the operation determination unit 103 activates the protection device 30. If there is no abnormality in the satellite G sensor 12B in step S105 (S105: No), then the protection device 30 is not activated and this routine ends.

[0052] In step S101, if the acceleration G1 is not greater than the main threshold value α (S101: No), in step S107, it is determined whether the acceleration G1 is greater than the main threshold value β (β<α) and the acceleration G2 is greater than the safing threshold value γ (γ>>δ). In step S107, if the acceleration G1 is greater than the main threshold value β and the acceleration G2 is greater than the safing threshold value γ (S107: Yes), in step S106, the operation determination unit 103 activates the protection device 30. In step S107, if the acceleration G1 is not greater than the main threshold value β or the acceleration G2 is not greater than the safing threshold value γ (S107: No), the protection device 30 is not activated and this routine ends.

[0053] As described above, according to this embodiment, a multiplex system is configured with the main determination unit 101 and the safing determination unit 102, and when a collision between the vehicle C and an object is predicted, the safing threshold value Ts is changed to a value ε smaller than the normal value δ. This makes it possible to appropriately operate the protection device 30 even in a situation where a low acceleration G2 for safing determination is detected due to the type of collision or the like (for example, an offset collision on the opposite side to the installation position of the satellite G sensor 12B, etc.).

[0054] In this embodiment, the safing determination unit 102 permits the operation of the protection device 30 when the collision prediction unit 104 predicts that the vehicle C will collide with an object when the satellite G sensor 12B is abnormal. This allows the protection device 30 to be operated even when the satellite G sensor 12B is abnormal. That is, a dual system is configured as a fail-safe by the collision prediction result by the stereo camera unit 15 and the judgment result by the protection device control unit 11. Furthermore, by using the collision prediction result by the stereo camera unit 15, the operation function of the protection device 30 can be continued without prohibiting the operation of the protection device 30 when the satellite G sensor 12B is abnormal.

[0055] In addition, in this embodiment, a configuration is shown in which a collision between the vehicle C and an object is predicted based on image data acquired from the stereo camera unit 15, but the method of predicting a collision is not limited to this. For example, a collision may be predicted using, as peripheral information, image data acquired by a monocular camera, information acquired from an external recognition means such as a millimeter wave radar, a laser radar such as a LIDAR (Light Detection And Ranging) sensor, or a yaw rate sensor for automatic braking control.

[0056] The program for causing a computer (protection device ECU 13) to execute the processing for realizing the functions of the occupant protection system 1 as described above can be provided by recording it in an installable or executable file format on a computer-readable recording medium such as a CD (Compact Disc)-ROM, a flexible disk (FD), a CD-R (Recordable), or a DVD (Digital Versatile Disk). The program may also be provided or distributed via a network such as the Internet. The program may also be provided by being pre-installed in a ROM or the like.

[0057] Although the embodiment of the present invention has been described above, the above-mentioned embodiment is presented as an example and is not intended to limit the scope of the present invention. This new embodiment can be implemented in various other forms. In addition, various omissions, substitutions, and modifications can be made without departing from the gist of the invention. In addition, this embodiment is included in the scope and gist of the invention, and is included in the scope of the invention and its equivalents described in the claims. [Explanation of symbols]

[0058] 1...Occupant protection system, 11...Protection device control unit, 12A...Built-in G sensor (first sensor), 12B...Satellite G sensor (second sensor), 13...Protection device ECU (control device for protection device), 15...Stereo camera unit, 30...Protection device, 101...Main determination unit, 102...Safing determination unit, 103...Activation determination unit, 104...Collision prediction unit, C...Vehicle, Ts...Safing threshold

Claims

1. A control device for a protection device that controls a protection device for protecting an occupant of a vehicle, a main determination means for determining whether or not a collision has occurred between the vehicle and an object based on an acceleration detected by a first sensor installed in the vehicle; a safing determination means for permitting the operation of the protection device when the acceleration detected by a second sensor installed at a position of the vehicle different from that of the first sensor is greater than a threshold value; an operation determination means for activating the protection device when the main determination means determines that a collision has occurred and the safing determination means permits activation of the protection device; a collision prediction means for predicting whether or not the vehicle will collide with an object present in the vicinity of the vehicle based on surrounding information indicating a situation in the vicinity of the vehicle; Equipped with the safing determination means sets the threshold value to be smaller when it is predicted that the vehicle will collide with the object than when it is predicted that the vehicle will not collide with the object; Control device for protective device.

2. the safing determination means permits the operation of the protection device when a collision between the vehicle and an object is predicted when an abnormality occurs in the second sensor. The control device for a protection device according to claim 1 .

3. The second sensor is installed at a position shifted to one side from a center portion in a width direction of the vehicle, the collision prediction means predicts a collision between the vehicle and an object in an area on a side where the second sensor is not installed, the safing determination means, when it is predicted that the vehicle will collide with an object in an area on the side where the second sensor is not installed, sets the threshold value to be smaller than that when it is predicted that the vehicle will not collide with an object. The control device for a protection device according to claim 1 .

4. The collision prediction means further predicts a collision mode of a collision between the vehicle and an object, The safing determination means changes the threshold value depending on the collision type. The control device for a protection device according to any one of claims 1 to 3.

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