JP2007168635A - Vehicular occupant detection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicular occupant detection device capable of stably detecting determination of existence of a child seat in occupant detection even during traveling. <P>SOLUTION: A plurality of load sensors 3a-3d are provided so as to detect load at different positions of the seat 4. The ECU 2 for occupant detection is processing for determining a degree of possibility that the child seat is attached; processing for applying a low pass filter to a ratio value of detection values of load sensors 3b, 3d at the outside of the vehicle and total load of the load sensors 3a-3d when it is determined that the possibility that the child seat is attached is high; and processing for determining existence of the child seat from the detection values of the load sensors 3a-3d and the detection value filter-processed by the low pass filter. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention belongs to the technical field of a vehicle occupant detection device that detects whether an occupant is seated on a vehicle seat.

Conventionally, in order to attach the child seat to the vehicle seat, the presence or absence of the child seat is determined by the load being concentrated on the door side of the vehicle seat to which the locking clip for binding the seat belt is attached. Specifically, in the arrangement where the load sensors detect at four locations on the front, rear, left and right of the vehicle seat, the presence or absence of a child seat is determined by comparing the output values of the load sensor where the load is concentrated by mounting with a locking clip and other load sensors. (For example, refer to Patent Document 1).
JP 2001-191830 A (page 2-9, full view)

  However, conventionally, there is a possibility of erroneously detecting an adult seated state and a child seated on a child seat due to a loss of occupant balance when the vehicle turns while traveling. The weight of the child seated on the light adult and the child seat is almost the same, and the weight cannot be separated by the total weight. Determine if the child is seated in an adult or child seat. However, when a light adult performs a turning run with the side determined by load concentration as the outer side while riding, there is a possibility that a load is applied to the outside due to the centrifugal force and the child seat is erroneously determined.

  The present invention has been made paying attention to the above-mentioned problems, and an object of the present invention is to provide a vehicle occupant detection device capable of stably detecting whether or not a child seat is present in occupant detection even while traveling. There is to do.

  In order to achieve the above object, in the present invention, a vehicle occupant comprising: a load sensor that detects a load applied to a vehicle seat; and a determination unit that calculates a detection result of the load sensor and determines at least the presence or absence of an occupant. In the detection device, a plurality of the load sensors are provided so as to detect loads at different positions of the seat, and the determination means includes an auxiliary device mounting estimation means for determining a high possibility that the child seat is mounted, and the child seat includes When it is determined that there is a high possibility of being mounted, the filter means for applying a low-pass filter to the detection value of the load sensor outside the vehicle and the ratio value of the total load of each load sensor, the detection value of the load sensor, and the Auxiliary device wearing determination means for determining the presence or absence of a child seat from the ratio value filtered by the filter means To.

  Therefore, in the present invention, it is possible to stably detect the presence / absence of the child seat in the occupant detection even during traveling.

  Hereinafter, an embodiment for realizing the vehicle occupant detection device of the present invention will be described based on Example 1. FIG.

First, the configuration will be described.
FIG. 1 is a diagram illustrating a configuration example of an airbag system using the vehicle occupant detection device according to the first embodiment. FIG. 2 is a block diagram of an airbag system using the vehicle occupant detection device of the first embodiment.
The airbag system according to the first embodiment mainly includes an airbag ECU 1, an occupant detection ECU 2, load sensors 3 a to 3 d, an occupant state display lamp 6, an airbag 7, and a warning lamp 8.

The airbag ECU 1 has a built-in CPU 11 and is not deployed when there is no occupant, deployed in the case of an adult, or not deployed when a child seat is installed, based on the occupant information obtained from the occupant detection ECU 2. Perform deployment control.
The occupant detection ECU 2 incorporates a CPU 21, processes the output from the load sensor 3, determines the presence of the occupant, whether the occupant is an adult or a child, and outputs the determination result.
The load sensors 3a to 3d output detection voltages according to the load at four different positions on the seat.

The occupant state display lamp 6 displays, for example, detection results of occupant states such as no occupant, an adult, and a child seat.
The airbag 7 is deployed to protect the occupant during a vehicle collision and exhibits a buffer function. Further, the expansion stage can be changed to at least two stages by the control.
The warning lamp 8 is an indicator lamp for displaying a warning when a failure in the airbag system is detected.

FIG. 3 is an explanatory diagram illustrating a mounting structure of load sensors 3a to 3d of the vehicle occupant detection device according to the first embodiment. 3A is a plan view, FIG. 3B is a side view, and FIG. 3C is a front view.
The four load sensors 3a to 3d are respectively provided at the right front part, the rear part, the left front part, and the rear part that support the load on the seat rail 5 of the seat 4 of the vehicle. Thereby, the load to each part is detected.

Next, the operation will be described.
[About airbag system]
Here, the airbag system of Example 1 will be described.
In the airbag system of the first embodiment, the airbag 7 changes the magnitude of deployment at the time of a vehicle collision into at least two stages.
In other words, the vehicle occupant detection device detects three states of no occupant, a child's seat, and an adult's seat, and in accordance with this state, the airbag 7 is not deployed when no occupant is present. In this case, the vehicle is controlled to expand in a small manner, and in the case where the occupant is an adult, the vehicle is expanded greatly.

As a result, the cushioning mechanism of the airbag 7 can be exhibited appropriately according to the state of the occupant.
In the first embodiment, as described above, regardless of wearing the seat belt, it is possible to stably detect the occupant information even while traveling, thereby contributing to the function of the air bag 7 that is appropriate for the state of the occupant. To do.

[Load monitoring and filtering]
FIG. 4 is a flowchart showing the flow of the load monitoring process and the filter process determined by the CPU 21 of the occupant detection ECU 2 of the first embodiment of the first embodiment. Each step will be described below.

In step S1, it is determined from the total load of the load sensors 3a to 3d whether the child seat is highly likely to be attached.
This judgment is made by summing the total load of the load sensors 3a to 3d, adding a child seat minimum load, for example, 29kg α, adding a child seat maximum load to a child maximum load, and adding a load applied by tightening the child seat. If β is β, it is determined whether α ≦ Sum ≦ β is satisfied. If it is within this range, the possibility of a child seat is high, and the process proceeds to step S2, and if it is outside this range, the possibility of a child seat is very high. To go to step S4.

In step S2, it is determined whether the load is uneven.
In this determination, the detection value of the front outer load sensor 3b is Fo as the front outer, the detection value of the rear outer load sensor 3d is Ro as the rear outer, and the determination value is 0.65 as an example, and (Fo + Ro) / It is determined whether Sum> 0.65. If 0.65 is exceeded, the process proceeds to step S3. If not, the process proceeds to step S4.

  In step S3, a low-pass filter (LPF) is applied to the ratio of the output values of the outer load sensors 3b and 3d to the total load, that is, (Fo + Ro) / Sum.

  In step S4, occupant determination is performed based on the total load, and if the total load is within a predetermined range, the presence / absence of a child seat is determined by determination using (Fo + Ro) / Sum.

[Stabilization during driving]
FIG. 5 is an explanatory diagram illustrating a determination state based on the presence or absence of filter processing in the vehicle occupant detection device of the first embodiment.
In the first embodiment, the occupant detection seat is a passenger seat located on the front right side. Furthermore, the detection value of the left front load sensor 3a is set to Fi as the front inner, the detection value of the right front load sensor 3b is set to Fo as the position of the front outer, and then the detection value of the left rear load sensor 3c. Ri as the position of the rear inner, and then the detected value of the load sensor 3d at the right rear is Ro.

The detection values of the load sensors 3a to 3d are shown by lines 30 to 33 in FIG. Further, the total load is indicated by a line 50, and the total of the detected values of the load sensors 3b and 3d on the outside with respect to turning is divided by the total load, that is, (Fo + Ro) / Sum is indicated by a line 40.
In FIG. 5 (a), the left and right balance is lost due to the turning of the vehicle, and the detection values of the load sensors 3b and 3d on the outside of the turning are divided by the total load, that is, (Fo + Ro) / Sum is , It fluctuates and falls below the judgment value line 60 and is erroneously detected.

  On the other hand, in FIG. 5 (b), the ratio of the values of the load sensors 3b and 3d, which are outside when turning, to the total load is monitored by the process of step S2. When the determination value (0.65) is exceeded, that is, when it is determined that there is a child seat, a tight low-pass filter is applied to the ratio values of the load sensors 3b and 3d that are on the outside during turning. Thereby, the erroneous determination at the time of turning can be prevented. That is, the (Fo + Ro) / Sum line 40 in FIG. 5B is a stable value.

  In addition, if all the load values of the load sensors 3a to 3d are subjected to a tight low-pass filter, problems such as responsiveness occur. However, by applying a tight low-pass filter only to the ratio value of the load that is outside during turning, the response It is possible to prevent erroneous determination of the presence or absence of a child seat without affecting the performance at all.

Next, the effect will be described.
In the vehicle occupant detection device according to the first embodiment, the effects listed below can be obtained.

  (1) In a vehicle occupant detection device including a load sensor 3 that detects a load applied to a vehicle seat 4 and an occupant detection ECU 2 that calculates a detection result of the load sensor 3 and determines at least the presence or absence of an occupant. A plurality of load sensors 3a to 3d are provided so as to detect loads at four different positions, and the occupant detection ECU 2 determines whether there is a high possibility that the child seat is mounted, and the child seat is mounted. When it is determined that there is a high possibility that the load sensor 3b, 3d is detected, the ratio value between the detected values of the load sensors 3b and 3d outside the vehicle and the total load of the load sensors 3a to 3d is subjected to a low pass filter, Since the process of step S4 for determining the presence / absence of a child seat from the detection value of 3d and the detection value filtered by the low-pass filter is provided, It is possible to stably detect the presence / absence of a child seat in the knowledge even while traveling.

The effects of the first embodiment will be additionally described. In the first embodiment, the occupant detection basically detects the state of no adults, children and no occupant by comparison with a threshold value based on the total load.
This is the relationship between the line 50 and the line 70 shown in FIG. A line 50 exceeding line 70 indicates that it is determined that the child is seated on an adult or child seat.
On the other hand, when the child seat is attached, the use of the child becomes clear. As an airbag system, an airbag is not deployed for a child seat seat. This is to prevent the airbag from pressing the child or the child seat.

  Therefore, it tries to detect the seating of the child seat and the child's seating on the child seat. Then, a load range that is difficult to judge arises.

  In contrast, in the first embodiment, unlike the conventional case, the child seat is attached to the vehicle seat 4 by the ratio (Fo + Ro) / Sum of the load sensors 3b, 3d on the door side that are outside when turning and the total load. The characteristic load at the time is detected. This is the relationship between the line 40 and the line 60 in FIG. 5, and when the line 40 of (Fo + Ro) / Sum exceeds the line 60 that is the judgment value, it is detected that the child is seated on the child seat. .

  In addition, in the first embodiment, when the value of (Fo + Ro) / Sum exceeds the line 40, a low-pass filter is applied, and thereafter, the vehicle turns as shown in FIG. Even if it occurs, the (Fo + Ro) / Sum value does not react sensitively to prevent false detection. As a result, when the vehicle is traveling, stable occupant detection can be performed including turning.

  When the child leaves the child seat, the value of (Fo + Ro) / Sum gradually returns due to the delay time due to the low-pass filter, and returns to the state of detection based on the basic total load. Actually, when the child leaves the child seat, the vehicle is stopped, so there is no influence on basic detection. Therefore, stable detection at the time of traveling is made possible without affecting the occupant detection system.

The effect of preventing erroneous detection at the time of turning is a situation where the airbag system is required to act particularly accurately, so that the effect as an airbag system is great.
In addition, obtaining such an operational effect with a low-pass filter is excellent in that it is easy to actually use in a vehicle because the cost is suppressed.

  As mentioned above, although the vehicle occupant detection device of the present invention has been described based on the first embodiment, the specific configuration is not limited to these embodiments, and the invention according to each claim of the claims. Design changes and additions are permitted without departing from the gist of the present invention.

The load sensor includes one using a strain gauge or fluid, and any sensor may be used as long as it can accurately detect the occupant's load.
Moreover, it is good also as a load sensor fewer than Example 1 by supplementing with another sensor and information.
In the first embodiment, the front passenger seat located on the right front side of the vehicle has been described. However, the front passenger seat may be used at a different position or may be other than the front passenger seat.
Further, the low-pass filter may be a soft low-pass filter or may be executed by a circuit or an element.

It is a figure which shows the structural example of the airbag system using the passenger detection apparatus for vehicles of Example 1. FIG. 1 is a block diagram of an airbag system using the vehicle occupant detection device of Embodiment 1. FIG. It is explanatory drawing which shows the attachment structure of the load sensors 3a-3d of the vehicle occupant detection apparatus of Example 1. FIG. Each step will be described below with reference to a flowchart showing the flow of load monitoring processing and filter processing determined by the CPU 21 of the occupant detection ECU 2 of the first embodiment of the first embodiment. It is explanatory drawing which shows the determination state by the presence or absence of the filter process in the vehicle occupant detection device of the first embodiment.

Explanation of symbols

1 Airbag ECU
11 CPU
2 ECU for passenger detection
3 Load sensors 3a to 3d Load sensor 4 Seat 5 Seat rail 6 Occupant status display lamp 7 Air bag 8 Warning lamp

Claims (1)

A load sensor for detecting a load applied to a vehicle seat;
A determination means for calculating a detection result of the load sensor and determining at least the presence or absence of an occupant;
In a vehicle occupant detection device comprising:
A plurality of load sensors are provided so as to detect loads at different positions of the seat,
The determination means includes
Auxiliary device wearing estimation means for judging the high possibility that a child seat is worn,
Filter means for applying a low-pass filter to the detection value of the load sensor on the outside of the vehicle and the ratio value of the total load of each load sensor when it is determined that the child seat is highly likely to be mounted;
Auxiliary device wearing determination means for determining the presence or absence of a child seat from the detection value of the load sensor and the ratio value filtered by the filter means;
A vehicle occupant detection device comprising:

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