JP4261295B2 - Occupant detection device - Google Patents

Description

  The present invention relates to an occupant detection device that is provided mainly in a seat of a vehicle such as an automobile and detects an occupant seated by the weight of the seat.

  Conventionally, for example, when an occupant is not seated in a passenger seat or when the occupant is a child even when seated, the seat is used as a device that is used to prevent deployment of an airbag such as a passenger seat. An occupant detection device that detects an occupant is known.

  In such an occupant detection device, for example, there are various methods for detecting an occupant, such as one that detects an occupant's body temperature using an infrared sensor or one that detects a reflected wave using an ultrasonic sensor, For example, if a sensor for detecting the weight is provided in a passenger seat or the like and if there is a passenger seated by detecting the weight applied to this seat, whether the passenger is an adult or a child An occupant detection device that can determine the type of the vehicle has been devised (for example, Patent Document 1).

Thus, in the occupant detection device that determines the occupant type based on the occupant's weight, for example, an initial value of a weight threshold value for determining whether the occupant is an adult or a child is set in advance, and the detected weight value is If it is above this threshold value, it is determined to be an adult, and conversely, if it is below this threshold value, a method of determining a child is considered. In addition, the weight value detected by the weight sensor etc. fluctuates with a certain width due to the vibration of the vehicle or changes in the seating state of the occupant (occupant posture, etc.), so the detected weight value is sampled in time series, Threshold when all of the weight data sampled within a certain period of time are equal to or greater than the threshold value (that is, all the results judged from each of the weight data within a certain period of time are adults) When the value is changed to a value lower than the initial value, and all the weight value data sampled within a certain time is less than the threshold value (that is, the result determined from each of the weight value data within the certain time) If all of the children are children), the threshold value is changed to a value higher than the initial value, and it is easy due to changes in the vehicle vibration and occupant seating status (occupant posture, etc.) Result of the determination so that never varies.
Japanese Patent No. 3040379

  However, in this conventional occupant detection device, for example, when an occupant whose weight is in the vicinity of the initial value of the threshold value is seated on the seat, the detected weight value moves up and down the threshold value each time. There is a problem that the result of judgment becomes an adult or a child.

  FIG. 6 is an example of a graph showing the weight value data detected by this conventional occupant detection device. In FIG. 6, in the period L1 in which the weight value data is equal to or greater than the initial threshold value T, the occupant is determined to be an adult, while in the period L2 in which the weight value data is less than the initial threshold value T. The passenger is determined to be a child.

  As described above, in the conventional occupant detection device, the weight value data moves up and down in the vicinity of the threshold value, so that the occupant type is erroneously determined and the determination result is stabilized. However, there is a problem that the detection accuracy is inferior. Further, if the determination result does not remain stable for a certain period of time, the threshold value is not changed from the initial value, and such an unstable state always continues.

  The present invention has been made in view of such a problem, and even when an occupant whose weight is in the vicinity of a threshold value is seated on the seat, the occupant can accurately detect the occupant with good detection accuracy. It is an object to provide a detection device.

In order to solve such a problem, the invention according to claim 1 is directed to a weight value detecting means for detecting a weight value applied to a seat of a vehicle, and a weight value detected by the weight value detecting means in time series. Sampling means for sampling the data, data determining means for determining whether each of the predetermined number of weight value data sampled by the sampling means is equal to or greater than a predetermined threshold value, and the threshold by the data determining means. Determining means for determining whether or not the number of weight value data determined to be equal to or greater than a reference number is greater than or equal to a reference number, wherein the reference number is variable, and includes one weight value data and the one weight value. If the judgment result of the data determination means and the next weight value data and contiguous data are different, it is possible to vary the reference number, before the said determining means When it is determined that the number of weight value data is greater than or equal to the reference number, the seat occupant is an adult, and when the number of weight value data is determined not to be greater than or equal to the reference number, the seat The passenger is not seated or the passenger is a child.

According to a second aspect of the present invention, there is provided weight value detection means for detecting a weight value applied to a vehicle seat, sampling means for sampling the weight value detected by the weight value detection means in time series, and the sampling means. Data discriminating means for discriminating whether or not each of the predetermined number of weight value data sampled by the data is equal to or greater than a predetermined threshold value, and the weight value data determined by the data discriminating means not to be equal to or greater than the threshold value Determination means for determining whether or not the number is equal to or more than a reference number, and the determination result of the data determination means is one weight value data and the next weight value data continuous with the one weight value data. If different, it is possible to change the sampling period of time of time series sampled weight values in the sampling unit, the determination hand When it is determined that the number of the weight value data is equal to or greater than the reference number, it is assumed that no occupant is seated on the seat or the occupant is a child, and the number of weight value data is not equal to or greater than the reference number. If it is determined that the occupant of the seat is an adult, the occupant of the seat is an adult.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the data discriminating unit removes the oldest weight value data from the predetermined number of weight value data, and the newest weight value data. Is added to obtain a new predetermined number of weight value data.

  Since the present invention is configured as described above, even when an occupant whose weight is near the threshold is seated on the seat, the occupant can be accurately detected with good detection accuracy.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a block diagram for schematically explaining an occupant detection device according to an embodiment of the present invention. The occupant detection device 1 includes a weight sensor (weight value detection means) 2 and a control unit (sampling means, data determination means, determination means) 3. The weight sensor 2 is provided in the seat part 5 of the passenger seat 4 of the automobile, detects the weight applied to the seat part 5, and outputs the detected weight value to the control part 3 as a weight signal.

  The control unit 3 includes a CPU 6, a ROM 7, and a RAM 8. The ROM 7 stores a control program for the CPU 6, and the RAM 8 is used as a temporary data storage area necessary for executing the program. The CPU 6 uses the RAM 8 as a work area in accordance with a program stored in the ROM 7 and controls operations of the occupant detection device 1 and the airbag device 10.

  The weight value detected by the weight sensor 2 is input to the control unit 3 as a weight signal, and the CPU 6 determines whether or not an occupant is seated in the passenger seat 4 based on the weight signal, and if it is seated. The passenger is judged to be an adult or a child. When the CPU 6 determines that the passenger is not seated in the passenger seat 4 or is seated even if the passenger is seated, the control unit 3 sends a signal for prohibiting the airbag device 10 to deploy the airbag. On the other hand, when the CPU 6 determines that the occupant seated in the passenger seat 4 is an adult, the control unit 3 outputs a signal that allows the airbag device 10 to deploy the airbag. .

  FIG. 2 is a flowchart for explaining the operation from when the control unit 3 of the occupant detection device 1 receives the weight signal until the occupant type determination is made. First, the control unit 3 performs a sampling process (S10). That is, the control unit 3 samples the weight signal from the weight sensor 2 in time series, and obtains weight value data x1, x2,... Xn for the number n of samples as a predetermined number set in advance.

  Next, when n pieces of weight value data x1, x2,... Xn are obtained, the control unit 3 performs data discrimination. That is, the CPU 6 determines whether or not the weight values of the weight value data x1, x2,... Xn are each equal to or greater than a preset threshold value T, and the weight value data x1, x2,. Classify each. Specifically, the CPU 6 reads the weight value data from the RAM 8 to determine whether the weight values of the respective weight value data x1, x2,... Xn are each equal to or greater than the threshold value T. Sets the A / C flag of the weight value data to 1 and sets the A / C flag of the weight value data to 0 when it is less than the threshold value T. Then, the value of the A / C flag of each weight value data x1, x2,... Xn is stored in the RAM 8.

  After performing discrimination / classification in this way, the control unit 3 performs occupant type determination processing (S20). That is, the CPU 6 calculates the number y of weight value data (weight value data whose weight value is equal to or greater than the threshold value T) of the A / C flag = 1 among the n weight value data x1, x2,. The occupant of the passenger seat 4 is detected based on whether the number of data y with the A / C flag = 1 is equal to or greater than the determination reference number S as the reference number set in advance. Here, the judgment reference number S is determined that the number of data y of the A / C flag = 1 among the weight value data x1, x2,. The CPU 6 determines that an adult is seated in the passenger seat 4 if the CPU 6 determines that the data number y of the A / C flag = 1 is equal to or greater than the determination reference number S. On the other hand, if it is determined that the data number y of the A / C flag = 1 is less than the determination reference number S, the passenger is not seated in the passenger seat 4 or the passenger is a child even if seated. Judge that there is. The larger the criterion number S of the sample number n, the more difficult it is to be determined as an adult.

  Based on the determination result, the control unit 3 outputs to the airbag device 10 either a signal that allows the airbag to be deployed or a signal that prohibits the deployment of the airbag.

  In addition, when the control unit 3 obtains the weight value data xn + 1 by newly sampling the weight signal from the weight sensor 2 in the sampling process of step S10, the control unit 3 adds the newest weight value data xn + 1 and the oldest weight value data. Data discrimination processing is newly performed as n weight value data x2,... xn, xn + 1 excluding x1. Subsequently, in step S20, occupant type determination processing is performed based on n pieces of weight value data x2,... Xn, xn + 1. In this way, the control unit 3 removes the oldest weight value data, adds the newest weight value data, and repeats the processes of step S10 and step S20 as new weight value data.

  In the occupant detection device 1 according to this embodiment, the weight value data of the A / C flag = 1 of the weight value data x1, x2,. Since the passenger y in the front passenger seat 4 is detected based on whether or not the number y of the data) is equal to or greater than the judgment reference number S, the type of the passenger may be determined by one weight value data as in the prior art. Instead, the type is determined based on the weight value data corresponding to n samples. Therefore, for example, even when an occupant whose weight is in the vicinity of the threshold value T is seated on the passenger seat 4, the occupant type determination is performed based on more data than in the conventional occupant detection device. An occupant can be accurately detected by the detection accuracy.

  FIG. 3 is a diagram for explaining a case where the occupant detection device 1 determines the occupant type using data similar to the weight value data shown in the graph of FIG. 6. Here, the case where the sample number n = 20 and the judgment reference number S = 15 is taken as an example. Further, “data number” in FIG. 3 is a number assigned to each weight value data for convenience, and “value of y when the number of samples n = 20” starts from one weight value data. The number y of weight value data (weight value data whose weight value is equal to or greater than the threshold value T) with A / C flag = 1 is selected from the previous 19 weight value data (total 20 weight value data). It is shown.

  Here, for example, 20 weight value data of data numbers 39 to 58 in FIG. 3 are extracted, and the number of weight value data (weight value data whose weight value is equal to or greater than threshold value T) with A / C flag = 1. Looking at how many y's, y = 16 as shown in FIG. In this case, since the data number y (= 16) of the A / C flag = 1> the determination reference number S (= 15), the occupant detection device 1 determines that an adult is seated on the passenger seat 4. Similarly, when 20 weight value data of data numbers 40 to 59 are extracted, the number of data y of A / C flag = 1 is y = 16, and the number of data y of A / C flag = 1 is greater than the judgment reference number S. Therefore, the occupant detection device 1 determines that an adult is seated in the passenger seat 4.

  In this way, in the occupant detection device 1, as can be seen from the fact that all the “values of y when the number of samples n = 20” shown in the graph of FIG. It is determined that an adult is seated in the passenger seat 4. On the other hand, even with the same weight value data, the conventional occupant detection device determines the occupant type based on the weight value data one by one. The period (L1 shown in FIG. 6) and the period (L2 shown in FIG. 6) determined to be a child are mixed, and the determination result is not stable.

  Thus, as can be seen from the comparison between FIG. 3 and FIG. 6, the occupant detection device 1 of the present embodiment can detect the occupant accurately with better and more stable detection accuracy than the conventional occupant detection device. Can do.

  Further, in the above-described occupant detection device 1, when the weight value detected by the weight sensor 2 becomes stable, the value of the judgment reference number S is increased, and when the weight value changes greatly, the value of the judgment reference number S is restored. As described above, the determination reference number S may be variable.

  In this case, for example, a determination reference number change process (S30) is added as shown in FIG. 4 between the sampling determination process in step S10 and the occupant type determination process in step S20 shown in FIG. If the A / C flag value is the same as the previous weight value data (for example, the weight value data x1 when the first weight value data is the weight value data x2), the weight value is stable. If the A / C flag value is different, it is determined that the weight value is not stable and the determination reference number S is decreased by one.

  By adding the determination reference number changing process in step S30, when the occupant gets on and off and a certain time has passed and the situation is stable, the actual weight of the child, for example, when the child stands up in the passenger seat 4 Even if the weight sensor 2 detects the above weight value, it is more difficult to be affected by the weight sensor 2, and it is possible to prevent the determination result from easily fluctuating.

  Alternatively, in the above-described occupant detection device 1, the sampling period may be made variable so that the sampling period is lengthened when the weight value detected by the weight sensor 2 becomes stable, and the sampling period is restored when the weight value changes greatly. Good.

  In this case, for example, a sampling period changing process (S40) is added as shown in FIG. 5 between the sampling process in step S10 and the occupant type determination process in step S20 shown in FIG. Compared to the previous weight value data (for example, weight value data x1 when the first weight value data is weight value data x2), if the A / C flag value is the same, it is determined that the weight value is stable. If the A / C flag value is different, it is determined that the weight value is not stable, and the sampling period is shortened. Here, the sampling period means that the weight signal is sampled in time series in the sampling process of step 10 to obtain the weight value data x1, x2,... Xn for the number of samples n. To the next weight value data (for example, received value data x2 when one weight value data is x1).

  By adding the sampling cycle changing process in step S40, when the occupant's weight is not near the threshold value and the situation is stable, the sampling cycle is lengthened, and the processing load per unit time is increased. In addition to the reduction, it is possible to improve the effect of removing noise caused by changes in the posture of the occupant. When the situation changes and is not stable, the sampling cycle is shortened to increase the processing speed and enable a quick response.

  Note that the present invention is not limited to the above-described embodiment. For example, in this embodiment, the weight sensor 2 is used as the weight detection unit. However, as long as the weight of the occupant can be detected, for example, a pressure sensor or a load cell is used. It may be.

  Moreover, although the weight sensor 2 was demonstrated as what was provided in the passenger seat 4, it is not restricted to this, A driver's seat, a rear seat, etc. may be sufficient.

  Further, in this embodiment, in the occupant type determination process in step S20, the occupant is detected based on whether or not the number of data y of the A / C flag = 1 is greater than or equal to the determination reference number S. However, if the A / C flag = 0 An occupant may be detected based on whether or not the number of data is greater than or equal to the criterion number. In this case, the judgment reference number is that the passenger is seated in the passenger seat 4 when the number of data of the A / C flag = 0 among the weight value data x1, x2,. This is a number value that serves as a criterion for determining whether the occupant is a child even if he / she is seated, and the CPU 6 has determined that the number of data with the A / C flag = 0 is equal to or greater than the determination criterion number. In this case, it is determined that the passenger is not seated in the passenger seat 4 or that the passenger is a child even if the passenger is seated, while the number of data of the A / C flag = 0 is less than the determination reference number. If so, it is determined that an adult is seated in the passenger seat 4. The larger the criterion number S of the sample number n, the more difficult it is to be judged as a child.

It is a block diagram for demonstrating typically the crew member detection device concerning this example. 2 is a flowchart illustrating an operation from when a control unit of the occupant detection device of FIG. 1 receives a weight signal to when determining a passenger type. It is a figure explaining the case where the passenger | crew detection apparatus of FIG. 1 performs passenger | crew classification determination using weight value data. 7 is a flowchart for explaining another example of the operation from when the control unit of the occupant detection device of FIG. 1 receives a weight signal to when the occupant type determination is performed. 7 is a flowchart for explaining still another example of an operation from when the control unit of the occupant detection device of FIG. 1 receives a weight signal to when determining the occupant type. It is a figure explaining the case where the conventional occupant detection apparatus performs occupant classification judgment using weight value data.

Explanation of symbols

1 occupant detection device 2 weight sensor (weight value detection means)
3 Control unit (sampling means, data discrimination means, judgment means)
n Number of samples (predetermined number)
x1, x2,... xn, xn + 1 Weight value data T Threshold value S Judgment reference number (reference number)

Claims (3)

A weight value detecting means for detecting a weight value applied to a seat of the vehicle;
Sampling means for sampling the weight values detected by the weight value detecting means in time series;
Data discriminating means for discriminating whether or not each of the predetermined number of weight value data sampled by the sampling means is a predetermined threshold value or more;
Determining means for determining whether or not the number of weight value data determined to be equal to or greater than the threshold value by the data determining means is equal to or greater than a reference number;
The reference number is variable, and when the determination result of the data determination means is different between one weight value data and the next weight value data that is continuous with the one weight value data, the reference number can be changed. Is possible,
If it is determined by the determining means that the number of weight value data is equal to or greater than the reference number, it is determined that the seat occupant is an adult and the number of weight value data is not equal to or greater than the reference number. In this case, the occupant detection device is characterized in that no occupant is seated in the seat or the occupant is a child. A weight value detecting means for detecting a weight value applied to a seat of the vehicle;
Sampling means for sampling the weight values detected by the weight value detecting means in time series;
Data discriminating means for discriminating whether or not each of the predetermined number of weight value data sampled by the sampling means is a predetermined threshold value or more;
Determining means for determining whether the number of weight value data determined not to be equal to or greater than the threshold value by the data determining means is equal to or greater than a reference number;
If the discrimination result of the data discriminating unit is different between one weight value data and the next consecutive weight value data, the sampling when sampling the weight value in time series in the sampling unit The period can be changed,
When the determination means determines that the number of weight value data is equal to or greater than the reference number, it is assumed that no occupant is seated in the seat or the occupant is a child, and the number of weight value data is the reference number. If it is determined that the number of passengers is not greater than the number, the passenger in the seat is an adult.   2. The data determination unit according to claim 1, wherein the oldest weight value data is removed from the predetermined number of weight value data, and the newest weight value data is added to obtain a new predetermined number of weight value data. The occupant detection device according to claim 2.

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