JP2006266706A - Load detection apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a load detection apparatus capable of accurately discriminating anomalies of a load measuring means. <P>SOLUTION: The load detection apparatus is provided with a load sensor 7 mounted to a seat main body 1; a load measuring part 9 for determining a load value on the seat main body 1 on the basis of detection information of the load sensor 7; and an input means 10a for inputting anomalous load information indicating the occurrence of a phenomenon putting an anomalous load on the seat main body 1. The load measuring part 9 is provided with an anomaly discrimination part 10 for determining whether the load measuring part 9 is anomalous or not on the basis of both a first load value determined on the basis of detection information of the load sensor 7 prior to the input of the anomalous load information and a second load value determined on the basis of the detection information of the load sensor after the input of the anomalous load information in the case that the input means 10a inputs the anomalous load information. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a load detection device provided with a load sensor installed on a seat body and load measuring means for obtaining a load value applied to the seat body based on detection information of the load sensor.

  The load detection device as described above is installed in, for example, a driver's seat or a passenger seat of a vehicle, and whether or not a seated person is seated on the seat body according to the load value obtained by the load measuring means, and the seated person Is used to determine whether the seated person is an adult or a child.

In such a load detection device, if an abnormality occurs in the load measuring means due to a vehicle collision or the like, an appropriate load value cannot be obtained.
Therefore, the conventional load detection device is provided with an abnormality determination unit that determines whether or not there is an abnormality in the load measurement unit based on whether or not a large unbalanced load is applied to the seat body (for example, Patent Documents). 1).
In Patent Document 1, a plurality of load sensors are provided in a distributed manner in four directions, front, rear, left and right of the seat body, and the abnormality determination means has an output value of the load sensor set minus output in either the front, rear, left or right of the seat body. If it falls below the value, it is determined that there is an abnormality in the load measuring means.

JP 2003-232670 A

In the above conventional load detection device, when a large offset load is applied to the seat body, it is determined that there is an abnormality in the load measurement means. However, even if there is no abnormality in the load measurement means, a large offset load is applied to the seat body. May take.
For example, when the seat back of the seat body is tilted backward and the seat body is flattened, the occupant sits on the seat back side, or the occupant on the rear side of the seat body If you accidentally kick up
In such a case, in the conventional load detection device, there is a risk of erroneous determination if there is an abnormality in the load measuring means.

  The present invention has been made paying attention to this point, and an object of the present invention is to provide a load detection device capable of accurately discriminating abnormality of the load measuring means.

  In order to achieve this object, the first characteristic configuration of the load detection device according to the present invention is a load sensor installed in the seat body, and a load value applied to the seat body based on detection information of the load sensor. In the load detecting device provided with the required load measuring means, an input means for inputting abnormal load information generated when an excessive load acts on the seat body is provided, and the load measuring means is configured so that the input means When the abnormal load information is input, a first load value obtained based on the detection information of the load sensor before the input, and a second load value obtained based on the detection information of the load sensor after the input On the basis of the above, there is provided an abnormality determining means for determining whether or not the load measuring means is abnormal.

As a factor that causes an abnormality in the load measuring means, for example, a case where an excessive load acts on the seat body such as a vehicle collision can be considered. When an abnormality occurs in the load measuring means, the load value changes before and after the occurrence.
Therefore, in the present invention, the abnormality determination means determines whether or not there is an abnormality in the load measurement means based on the first load value and the second load value before and after the time when an excessive load is applied. Determine.
If it discriminate | determines in this way, it will be able to discriminate | determine whether a load measuring means has abnormality by detecting how the load value changed before and after the time of the case where an excessive load acts.
Therefore, according to the present invention, it is possible to provide a load detection device that can accurately determine abnormality of the load measuring means.

  In a second characteristic configuration of the load detection device according to the present invention, the abnormality determination unit sets a first time before the load value fluctuates on the basis of the time point when the input unit inputs the abnormal load information. The load value before the first time is used as the first load value to determine whether or not there is an abnormality in the load measuring means.

For example, when the vehicle collides with another object in front, the load value acting on the seat body greatly fluctuates, for example, a seated person on the seat body steps on the foot before the input means inputs abnormal load information. There is.
Therefore, in the present invention, the abnormality determination unit sets the first time, and obtains the load value before the first time as the first load value before the time point when the input unit inputs the abnormal load information.
Therefore, the abnormality determination means can determine whether or not there is an abnormality in the load measurement means by using the first load value obtained at a suitable timing, and can accurately determine this.

  According to a third characteristic configuration of the load detection device according to the present invention, the abnormality determination unit has a stable state in which the variation amount of the load value gradually decreases with reference to the time point when the input unit inputs the abnormal load information. The second time is set, and the load value after the second time is set as the second load value to determine whether or not there is an abnormality in the load measuring means.

After the input means inputs abnormal load information, an excessive load is applied and the load value fluctuates greatly.
Therefore, in the present invention, after the abnormality determination unit sets the second time and the input unit inputs the abnormal load information, the load value after the second time has elapsed and the state of the seat body is stabilized is the second value. Obtained as a load value.
Therefore, the abnormality determination unit can determine whether or not there is an abnormality in the load measurement unit by using the second load value obtained at a suitable timing, and can accurately perform the determination.

  In a fourth characteristic configuration of the load detection device according to the present invention, the abnormality determination unit obtains a difference between the first load value and the second load value, and the load measurement is performed when the obtained difference is equal to or larger than a set difference. It is comprised so that it may discriminate | determine that there exists abnormality in a means, and the said setting difference exists in the point which can be changed and set.

The abnormality determining means only needs to determine whether or not the difference between the first load value and the second load value is greater than or equal to the set difference in determining whether or not the load measuring means is abnormal. Can be simplified.
When the change in the load value caused by the abnormality of the load measuring unit differs depending on the magnitude of the load value applied to the seat body, the setting difference can be changed and set according to the magnitude of the load value applied to the seat body. Therefore, it is possible to more accurately determine whether there is an abnormality in the load measuring means.

  In a fifth characteristic configuration of the load detection device according to the present invention, the abnormality determination means obtains a ratio of a difference between the first load value and the second load value with respect to the first load value, and the obtained ratio is equal to or greater than a set ratio. In this case, the load measuring means is determined to be abnormal.

  The abnormality determination means obtains the ratio of the difference between the first load value and the second load value with respect to the first load value, thereby simply comparing the difference between the first load value and the second load value. The change between the first load value and the second load value can be accurately grasped. Therefore, it becomes easier to accurately determine whether there is an abnormality in the load measuring means.

  A sixth characteristic configuration of the load detection device according to the present invention is such that the abnormality determination means obtains a first load value and a second load value when a seated person is not seated on the seat body. It is in the point.

That is, the abnormality determination unit determines whether or not there is an abnormality in the load measurement unit using the first load value and the second load value when the seated person is not seated on the seat body.
In this way, it is possible to determine whether or not there is an abnormality in the load measuring means by changing the load value under the same condition that no seated person is seated on the seat body, and more accurate determination can be performed. It can be carried out.
In addition, since the seated person is not seated on the seat body, the state of the seat body hardly changes, and the most accurate values are obtained as the first load value and the second load value.

An embodiment of a load detection device according to the present invention will be described with reference to the drawings.
[First Embodiment]
This load detection device is installed, for example, in the seat body on the passenger seat side of the vehicle. As shown in the side view of FIG. 1, the seat body 1 is composed of a seat cushion 1a and a seat back 1b.
A lower frame 2 is fixed to the floor side of the vehicle, and an upper frame 3 is slidably provided on the lower frame 2.

Between the upper frame 3 and the cushion frame 4 in the seat cushion 1a, a front sensor bracket 5 positioned on the front side and a rear sensor bracket 6 positioned on the rear side are provided in the vehicle front-rear direction. ing.
The front side sensor bracket 5 and the rear side sensor bracket 6 respectively support a load sensor 7 made of, for example, a strain gauge.

In FIG. 1, the left side surface of the seat body 1 is shown, but the right side surface of the seat body 1 has the same configuration as the left side surface. Therefore, although illustration is omitted, a front sensor bracket 5 and a rear sensor bracket 6 are also provided on the right side surface of the seat body 1, and a load sensor is provided for each of the front sensor bracket 5 and the rear sensor bracket 6. 7 is arranged.
In this way, a total of four load sensors 7 are provided, one at each of four locations on the front left side, the front right side, the rear left side, and the rear right side of the seat body 1.

As shown in FIG. 2, the controller 8 of the load detection device is provided with a load measurement unit 9 as a load measurement unit for obtaining a load value applied to the seat body 1 based on detection information of the four load sensors 7. Yes.
For example, the load measuring unit 9 obtains the sum of the output values of the four load sensors 7 as a load value applied to the seat body 1. Then, the load measuring unit 9 obtains a load value, and repeatedly performs a load value calculation process for updating and storing the obtained load value every time a set time (for example, 100 msec) elapses.
Although not shown, the output value of the load sensor 7 is input to the load measuring unit 9 via an amplifier or a filter.

The load measuring unit 9 includes an abnormality determining unit 10 as an abnormality determining unit that determines whether or not the load measuring unit 9 has an abnormality.
When the abnormality determination unit 10 determines that there is an abnormality in the load measurement unit 9, an output unit 12 is provided that outputs the determination result to a notification means 13 such as an indicator lamp.

Hereinafter, determination of whether or not there is an abnormality in the load measurement unit 9 by the abnormality determination unit 10 will be described.
When an abnormal load information generated when an excessive load is applied to the seat body 1 is input, the abnormality determination unit 10 is obtained by the load measurement unit 9 based on detection information of the load sensor 7 before the input. It is determined whether or not there is an abnormality in the load measuring unit 9 based on the first load value and the second load value obtained by the load measuring unit 9 based on the detection information of the load sensor 7 after the input. It is configured.

The case where an excessive load acts on the seat body 1 is, for example, a vehicle collision. The load measuring unit 9 includes a collision determination unit 11 that determines whether or not a vehicle has collided based on detection information of the four load sensors 7.
When any of the output values of the four load sensors 7 falls below the set minus output value, the collision determination unit 11 determines that the vehicle is in collision.

When the collision determination unit 11 determines that the vehicle is a collision, the collision determination unit 11 outputs abnormal load information to the abnormality determination unit 10, and the abnormality determination unit 10 inputs abnormal load information from the load measurement unit 9. To do.
In this way, the abnormality determination unit 10 also serves as the input means 10a for inputting abnormal load information.

As illustrated in FIG. 3, the abnormality determination unit 10 sets a second time T <b> 2 at which the amount of change in the load value gradually decreases and becomes stable with reference to the point in time when the abnormal load information is input.
The second time T2 can be fixed or changeable. For example, the abnormality determination unit 10 updates and sets the second time every time the abnormal load information is input.
In this case, the abnormality determination unit 10 determines, for example, a point in time when the amount of change between the load value obtained in the previous load value calculation process and the load value obtained in the current load value calculation process is within the set range. As the time when the stable state is reached, the time from when the abnormal load information is input to when the stable state is reached is set as the second time T2.

In addition, the abnormality determination unit 10 sets a first time T1 before the load value fluctuates with reference to the time point when the abnormal load information is input.
The first time T1 can be fixed or changeable similarly to the second time. For example, the abnormality determination unit 10 updates and sets the first time each time the abnormal load information is input.
In this case, the abnormality determination unit 10 determines, for example, a point in time when the amount of change between the load value obtained in the previous load value calculation process and the load value obtained in the current load value calculation process exceeds the set range. As the point of time when the load value fluctuates, the time from the time when the abnormal load information is input to the point when the load value calculation process immediately before the point when the load value fluctuates is set as the first time.

As described above, when the abnormality determination unit 10 sets the first time T1 and the second time T2, the load obtained in the load value calculation process when going back to the first time T1 from the time when the abnormal load information is input. The value is obtained as the first load value K1, and the load value obtained by the load value calculation process after the second time T2 from the time when the abnormal load information is input is obtained as the second load value K2.
Then, the abnormality determination unit 10 determines a difference between the first load value K1 and the second load value K2, and determines that the load measurement unit 9 is abnormal if the calculated difference is equal to or greater than the set difference Q.
The abnormality determination unit 10 can change and set the setting difference Q. For example, the set difference Q can be changed and set according to the magnitude of the load value applied to the seat body 1, such that the set difference Q is set larger as the load value obtained in the load value calculation process is larger.

The operation of the load measuring unit 9 will be described based on the flowchart of FIG.
The load measuring unit 9 performs a load value calculation process (step 1). This load value calculation process is executed as an interrupt process every time a set time (for example, 100 msec) elapses.
And it is discriminate | determined whether the abnormality determination part 10 input abnormal load information (step 2).

When the abnormality determination unit 10 inputs abnormal load information, when the second time has elapsed from the input time point, the difference between the first load value K1 and the second load value K2 is obtained, and the obtained difference is set. It is determined whether or not the difference is equal to or greater than Q (steps 3 and 4).
If the difference between the first load value K1 and the second load value K2 is equal to or greater than the set difference Q, the abnormality determination unit 10 determines that there is an abnormality in the load measurement unit 9 (step 5).

[Second Embodiment]
In the second embodiment, the abnormality determination unit 10 is configured to obtain the first load value and the second load value when a seated person is not seated on the seat body 1.
Then, the abnormality determination unit 10 determines whether or not there is an abnormality in the load measurement unit 9 using the first load value K1 and the second load value K2 when the seat body 1 is not seated. .

The operation of the load measuring unit 9 in the second embodiment will be described based on the flowchart of FIG.
First, it is determined whether or not a seated person is seated on the seat body 1 (step 11). This determination is performed, for example, by providing a sensor (for example, a mat sensor or a seating sensor) that detects the presence of a seated person in the seat body 1 and inputting the output value of the sensor to the load measuring unit 9.
And it is discriminate | determined whether the abnormality determination part 10 input abnormal load information (step 12).

When the abnormality determination unit 10 does not input abnormal load information, if the load value K obtained by the load value calculation process is a zero point range (W1 <K <W2), then the load value K is obtained and stored as the first load value K1 (steps 13 and 14).
Incidentally, the load value calculation process is executed as an interrupt process every time a set time (for example, 100 msec) elapses.

If the abnormality determination unit 10 has input abnormal load information, then the difference between the load value K obtained in the load value calculation process and the first load value K1 is greater than or equal to the abnormality determination set value R. For example, the load value K is obtained and stored as the second load value K2 (steps 15 and 16).
And the abnormality determination part 10 calculates | requires the difference of the 1st load value K1 and the 2nd load value K2, and if the calculated | required difference is more than the setting difference Q, it will determine with the load measurement part 9 having abnormality ( Steps 17 and 18).

[Third Embodiment]
In the second embodiment, the abnormality determination unit 10 does not obtain the first load value K1 and the second load value K2 when the seated person is seated on the seat body 1, but the third embodiment In the embodiment, the abnormality determination unit 10 obtains the first load value K1 and the second load value K2 even when a seated person is seated on the seat body 1.

Then, when the seated person is seated on the seat body 1, the abnormality determination unit 10 obtains the first load value K1 and the second load value K2 as in the first embodiment, and obtains the obtained first value. Based on the load value K1 and the second load value K2, it is determined whether or not the load measuring unit 9 is abnormal.
Further, when the seated person is not seated on the seat body 1, the abnormality determination unit 10 obtains the first load value K1 and the second load value K2 as in the second embodiment, and obtains the first obtained value. Based on the load value K1 and the second load value K2, it is determined whether or not the load measuring unit 9 is abnormal.

The operation of the load measuring unit 9 in the third embodiment is the operation described in the first embodiment or the operation described in the second embodiment depending on whether or not a seated person is seated on the seat body 1. It is divided according to the case.
That is, if a seated person is seated on the seat body 1 in step 11 in FIG. 5, the process proceeds to step 1 in FIG. 4 and the operation described in the first embodiment is performed. Further, in step 11 in FIG. 5, when a seated person is not seated on the seat main body 1, the process proceeds to step 12 in FIG.

[Another embodiment]
(1) In the first to third embodiments, the abnormality determination unit 10 obtains a difference between the first load value K1 and the second load value K2, and if the obtained difference is equal to or greater than the set difference Q, the load Although it is determined that the measurement unit 9 has an abnormality, the abnormality determination unit 10 determines whether the load measurement unit 9 has an abnormality based on the first load value K1 and the second load value K2. It is possible to appropriately change whether to discriminate.

For example, the abnormality determination unit 10 obtains the ratio of the difference between the first load value K1 and the second load value K2 with respect to the first load value K1, and if the obtained ratio is equal to or greater than the set ratio, the load measuring unit 9 It may be determined that there is an abnormality.
Then, the abnormality determination unit 10 obtains the ratio Y (= | K1−K2 | / K1) by dividing the difference G between the first load value K1 and the second load value K2 by the first load value K1.

(2) In the first to third embodiments, the setting difference Q can be changed. However, the setting difference Q can be a fixed value.
Even when the setting difference Q can be changed, how the setting difference Q is changed can be changed as appropriate.

(3) In the first to third embodiments, the abnormality determination unit 10 also serves as input means for inputting abnormal load information. For example, as shown by the dotted line in FIG. Alternatively, an input unit 14 may be provided as input means for inputting abnormal load information.
In this case, a collision detection unit 15 that detects a vehicle collision using various sensors or the like is provided. When the collision detection unit 15 detects a vehicle collision, the abnormal load information is output to the input unit 14.

  As described above, when the input unit 14 and the collision detection unit 15 are provided, the load determination unit 11 may not be provided in the load measurement unit 9.

(4) In the first to third embodiments, the time until the variation amount of the load value gradually decreases and becomes stable with reference to the time when the abnormality determination unit 10 inputs the abnormal load information, Although the second time T2 is set, it is also possible to simply set the set time (for example, 5 seconds) as the second time T2, and how to set the second time T2 appropriately. It can be changed.

  Moreover, even when the time until the amount of fluctuation of the load value gradually decreases and becomes stable with the time point when the abnormal load information is input as the second time T2 is set as the second time T2, how is the stable state changed? It can change suitably about whether to detect.

(5) In the first to third embodiments, the abnormality determination unit 10 sets the time that goes back before the load value fluctuates as the first time T1 with reference to the time when the abnormal load information is input. However, it is also possible to simply set the set time (for example, 5 seconds) as the first time T1, and it is possible to appropriately change what time the first time T1 is set to.

  Further, even when the time when the load value fluctuates before the fluctuation of the load value is set as the first time T1 on the basis of the time when the abnormal load information is input, how the load value fluctuates becomes large. It can change suitably about whether to detect.

(6) In the first to third embodiments, a total of four load sensors 7 are provided, one at each of four positions on the front left side, the front right side, the rear left side, and the rear right side of the seat body 1. The number and arrangement location of 7 can be changed as appropriate. In selecting the number and arrangement location of the load sensors 7, it is preferable that the load sensor 7 can detect that an uneven load is applied to the seat body 1.

(7) In the first to third embodiments, the vehicle collision is illustrated as the case where an excessive load is applied to the seat body 1, but the vehicle is illustrated as the case where an excessive load is applied to the seat body 1. The present invention is not limited to the collision, and may be other cases.

  The present invention is provided with load sensors installed in various seat bodies such as a driver's seat and a passenger seat of a vehicle, and load measuring means for obtaining a load value applied to the seat body based on detection information of the load sensors. It can be applied to various load detection devices.

Side view of the seat body Block diagram of load detection device Explanatory drawing when obtaining the first load value and the second load value Flow chart in the first embodiment Flowchart in the second embodiment

Explanation of symbols

1 seat body 7 load sensor 9 load measuring means (load measuring section)
10 Abnormality discrimination means (abnormality discrimination part)
10a input means 14 input section (input means)
K1 first load value K2 second load value T1 first time T2 second time

Claims (6)

A load detection device provided with a load sensor installed on the seat body and a load measuring means for obtaining a load value applied to the seat body based on detection information of the load sensor,
Provided with an input means for inputting abnormal load information generated when an excessive load acts on the seat body,
The load measuring means, when the input means inputs the abnormal load information, the first load value obtained based on the detection information of the load sensor before the input, and the detection of the load sensor after the input A load detection device provided with an abnormality determining means for determining whether or not the load measuring means is abnormal based on a second load value obtained based on information.   The abnormality determination means sets a first time before the load value fluctuates with reference to the time point when the input means inputs the abnormal load information, and sets the load value before the first time as the first load value. The load detecting device according to claim 1, wherein the load measuring device is configured to determine whether or not there is an abnormality in the load measuring means.   The abnormality determination means sets a second time when the variation amount of the load value gradually decreases and becomes stable with reference to the time point when the input means inputs the abnormal load information, and after the second time, 3. The load detection device according to claim 1, wherein the load detection device is configured to determine whether or not there is an abnormality in the load measurement unit using the load value as the second load value. 4. The abnormality determining means is configured to determine a difference between the first load value and the second load value, and to determine that the load measuring means is abnormal when the calculated difference is equal to or greater than a set difference.
The load detection device according to claim 1, wherein the setting difference can be changed and set.   The abnormality determining means obtains a ratio of a difference between the first load value and the second load value with respect to the first load value, and determines that the load measuring means is abnormal when the obtained ratio is equal to or greater than a set ratio. The load detection device according to any one of claims 1 to 3, wherein the load detection device is configured to perform.   The said abnormality discrimination | determination means is comprised so that a 1st load value and a 2nd load value may be calculated | required when the seated person is not seated on the said seat main body. The load detection apparatus described.

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