JP2006123835A - Occupant detection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an occupant detection device preventing an erroneous determination of an occupant state by using results of determinations already made without making a new determination, when there is a possibility that the determination of the occupant state can not be accurately made. <P>SOLUTION: This occupant detection device 10 has an occupant determining part 12 for determining the occupant state by comparing output values that the occupant sitting on a seat 1 of a vehicle is measured by load sensors 4 ... with a threshold value set in advance. The determination results by the occupant determining part 12 are used for controlling an air bag 7. The determination results are stored in an EEPROM 15. When acceleration values outputted from G sensors 14A to 14C used for the control of the air bag 7 exceed an acceleration threshold value, already stored determination results are used. When the acceleration values are below the acceleration threshold value, the new determination of the occupant state is performed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an occupant detection device that determines the state of an occupant seated on a vehicle seat using an output value of a load sensor.

  Conventionally, as shown in FIG. 4, a load sensor 4,... Is attached to a support portion 3,... That supports the seat 1, and an occupant who determines whether the occupant is an adult or a child based on its output value. A detection device is known (see Patent Document 1).

  The seat 1 includes a seat cushion portion 1a that forms a seating surface and a seat back portion 1b that serves as a backrest, and each of the regions divided into four front, rear, left, and right regions has four locations. It is supported from below by the support portions 3.

  The support portions 3,... Are slidably attached to the seat rails 2, 2, and load sensors 4,... For detecting the weight of the occupant are attached. As the load sensor 4, a strain type load sensor is used.

  As shown in FIG. 5, the output values output from the four load sensors 4,... Are sent to the occupant determination unit 5, and the total of the output values is compared with the threshold value stored in the EEPROM 8. Is done.

  This threshold is a threshold for determining whether the occupant is an adult or a child. If the total output value is smaller than this threshold, it is determined that the occupant is a child. Determine that you are an adult.

  The determination result is sent to the airbag control unit 6 and used for switching the deployment amount of the airbag 7. That is, when the occupant is an adult, the airbag 7 is deployed as normally set at the time of an accident, and when the occupant is a child, the deployment of the airbag 7 is suppressed or stopped.

As a means for measuring the occupant's physique like the load sensor 4 described above, a means for measuring the occupant's pressure by arranging a pressure sensor in the seat cushion part 1a, and a pressure sensor for the seat cushion part 1a are also provided. Means for detecting the size and pressure sum of the occupant's buttocks arranged and seated are known.
JP 2004-122927 A (FIGS. 1 to 4)

  However, in the above-described conventional occupant detection device, when the vibration of the occupant changes during the vehicle traveling, acceleration / deceleration, turning, banking, ramp traveling, etc. There is a case where the body size cannot be accurately measured because the weight is shifted to one side or the body is lifted from the seat cushion portion 1a.

  Even in such a case, if the occupant state is determined using the output value detected from the load sensor 4 or the like as it is, a correct determination result may not be obtained.

  Therefore, according to the present invention, when there is a possibility that the determination of the occupant state cannot be performed accurately, the occupant state is erroneously determined by using the determination result made so far without performing a new determination. An object of the present invention is to provide an occupant detection device that never happens.

  In order to achieve the above object, according to the first aspect of the present invention, the determination of the occupant state is made by comparing the output value obtained by measuring the occupant seated on the vehicle seat with the physique measuring means and a preset threshold value. An occupant detection unit that performs determination of the occupant determination unit, and the determination result of the occupant determination unit is used to control the occupant protection device. The determination result is stored in a storage unit for controlling the occupant protection device. When the acceleration value output from the used acceleration sensor exceeds the acceleration threshold, the stored determination result is used, and when the acceleration value is equal to or less than the acceleration threshold, the occupant detection apparatus newly determines the occupant state. It is characterized by that.

  According to the first aspect of the present invention, the vehicle state is determined from the acceleration value output from the acceleration sensor, and when there is a possibility that the occupant state may not be accurately determined, The occupant status is not determined.

  For this reason, an occupant protection device does not operate due to an erroneous determination result. Further, since the state of the vehicle is determined by the acceleration value, appropriate processing can be performed even when the occupant's posture changes even at a low speed, such as during turning.

  Furthermore, occupant protection devices such as airbags use acceleration values for their control and can use the data as they are, so existing parts can be used effectively, and occupant detection devices can be used at low cost. Judgment can be prevented.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  FIG. 1 shows a configuration of an occupant detection device 10 according to the present embodiment.

  First, as described from the configuration, the occupant detection device 10 according to the present embodiment includes a load sensor 4 as a physique measuring unit and an occupant determination unit 12 that determines the state of the occupant from its output value. .

  Furthermore, the determination result issued by the occupant determination unit 12 is transmitted to the airbag control unit 11 and used for controlling the airbag 7 as the occupant protection device.

  In the present embodiment, the physique of the occupant sitting on the seat 1 of the vehicle is measured by load sensors 4,... Arranged at four locations below the seat cushion portion 1a as shown in FIG.

  The load sensors 4,... Are attached to the seat rails 2, 2 fixed in parallel to the vehicle interior floor via support portions 3,. Further, a strain-type load sensor is used as the load sensor 4, and an output value proportional to the strain generated by the load acting on the support portions 3,.

  And the occupant determination part 12 of this Embodiment compares the sum total of four output values of the load sensors 4, ... with the threshold value memorize | stored in EEPROM15 as a memory | storage part, and a passenger | crew is an adult. Or child.

  The determination result by the occupant determination unit 12 is written and stored in the EEPROM 15 and sent to the airbag control unit 11 to suppress or stop the deployment of the airbag 7 when it is determined that the occupant is a child. To do.

  When it is determined that the occupant is an adult, the airbag control unit 11 performs control so that the airbag 7 is deployed as normally set.

  The airbag control unit 11 includes a CPU 13 as a control unit and G sensors 14A, 14B, and 14C as acceleration sensors.

  The G sensors 14A, 14B, and 14C are in the vertical direction, and include a G sensor 14A that detects acceleration in the X-axis direction that is the vehicle longitudinal direction, a G sensor 14B that detects acceleration in the Y-axis direction that is the vehicle width direction. There is a G sensor 14C that detects acceleration in the Z-axis direction.

  Based on the magnitude of acceleration values detected by these G sensors 14A, 14B, and 14C and temporal changes, it is determined whether or not an impact due to a vehicle collision accident or a drop has occurred, and the airbag 7 is deployed. When it is determined that the impact is a power impact, an ignition signal is sent to the ignition device to deploy the airbag 7.

  In the present embodiment, the acceleration values detected by the G sensors 14A, 14B, and 14C are used to determine whether or not to determine the occupant state.

  That is, the acceleration values detected by the G sensors 14A, 14B, and 14C are sent to the occupant determination unit 12, and the occupant determination unit 12 checks whether there is an acceleration value that exceeds the acceleration threshold value. If there is an acceleration value exceeding, the occupant state is not newly determined.

  The acceleration threshold value is set for each of the G sensors 14A, 14B, and 14C because the direction of acceleration detected by the G sensors 14A, 14B, and 14C is different. For example, the acceleration threshold value of the G sensor 14A in the X-axis direction is set to an acceleration value that is large enough to cause the adult load distribution on the seat cushion portion 1a to fluctuate due to vehicle acceleration / deceleration.

  That is, in such a case, the weight is concentrated on the occupant's feet due to sudden deceleration, and the weight on the seat 1 may be reduced, so that it may be determined as a child.

  The acceleration threshold value of the G sensor 14B in the Y-axis direction is set to an acceleration value having such a magnitude that the adult load distribution on the seat cushion portion 1a changes when the vehicle turns.

  That is, during sudden turning, the passenger leans against the vehicle door or the center console, and the weight on the seat 1 may be reduced, so that the child may be judged.

  Further, the acceleration threshold value of the G sensor 14C in the Z-axis direction is such that the load distribution of adults on the seat cushion portion 1a fluctuates when the vehicle vibrates, falls, or rolls over. Set the acceleration value.

  This is because in such a state in which the occupant is caused to fluctuate in the vertical direction, the occupant may be lifted from the seat cushion portion 1a, and the weight on the seat cushion portion 1a may be reduced to be determined as a child.

  When the vehicle is in the state as described above, when a collision occurs to the extent that the airbag 7 does not deploy, or when the vehicle spins and the posture of the occupant fluctuates, There is a possibility that the occupant's weight fluctuates and a determination of the occupant state different from the actual state is made.

  On the other hand, since it is unlikely that the occupant will be replaced in such a vehicle state, the occupant state is not newly determined when an acceleration value that exceeds the acceleration threshold is detected.

  Next, the operation of the occupant detection device 10 will be described with reference to the flowchart shown in FIG.

  When the ignition key (not shown) is on, the load of the occupant seated on the seat 1 is detected by the four load sensors 4,... Every 2 to 3 seconds. Is output as an output value.

  Further, the weight W of the occupant is calculated by summing up these output values (S1). Here, since the occupant is usually seated on the floor, the calculated weight W is smaller than the weight of the occupant.

  Then, the acceleration value G detected by the G sensors 14A, 14B, and 14C is transmitted from the airbag control unit 11 to the occupant determination unit 12, and the three types of acceleration values G and the acceleration threshold value Gth are compared for each value. (S2).

  As a result, if any acceleration value G exceeds the acceleration threshold value Gth, the previous determination result stored in the EEPROM 15 is transmitted to the airbag control unit 11 without shifting to the determination process of the occupant state (S9). ).

  On the other hand, when all the acceleration values G are equal to or less than the acceleration threshold Gth, the process proceeds to a process for determining the occupant state. In this occupant state determination process, it is first determined whether or not the seat 1 is empty (S3).

  Here, when the weight W is equal to or less than the vacant seat threshold Eth, it is determined that the seat 1 is vacant (S7), and the determination result “vacant seat” is stored in the EEPROM 15 (S8). The stored determination result of “vacant seat” is also transmitted to the airbag control unit 11 (S9), and the airbag 7 of the seat 1 is controlled not to be deployed even at the time of collision.

  Furthermore, when the weight W exceeds the vacant seat threshold Eth, it is determined that an occupant is seated on the seat 1, and it is determined whether the occupant is an adult or a child (S4). Here, when the weight W is smaller than the occupant determination threshold Wth, it is determined that “the occupant is a child” (S6), and the determination result that “the occupant is a child” is stored in the EEPROM 15 (S8).

  The stored determination result that “the occupant is a child” is also transmitted to the airbag control unit 11 (S9), and the deployment amount of the airbag 7 of the seat 1 at the time of the collision is suppressed or the deployment is stopped. Such control is performed.

  When the weight W is equal to or greater than the occupant determination threshold Wth, it is determined that “the occupant is an adult” (S5), and the determination result “the occupant is an adult” is stored in the EEPROM 15 (S8).

  The stored determination result that “the occupant is an adult” is also transmitted to the airbag control unit 11 (S9), and the airbag 7 is controlled when the occupant is an adult.

  The occupant detection device 10 of the present embodiment configured as described above determines the state of the vehicle at that time based on the acceleration value G output from the G sensors 14A, 14B, and 14C provided in the airbag control unit 11. However, when the vehicle is in a state where the determination of the occupant state may not be performed accurately, the determination of a new occupant state using the output value detected from the load sensor 4 at that time is not performed.

  For this reason, an incorrect determination result is transmitted to the airbag control unit 11, and the airbag 7 does not operate according to the incorrect determination result.

  Further, since the state of the vehicle is determined by the acceleration value G, it is possible to accurately determine a state in which the posture of the occupant changes compared to the case where the state of the vehicle is determined based on the vehicle speed or the like.

  For example, when the posture of the occupant changes even at a low speed, such as during turning, the acceleration value G of the G sensor 14B for the Y-axis direction exceeds the acceleration threshold Gth, so that a new occupant state determination is not performed. An appropriate process of using the determination result of the previous state can be performed.

  Further, since the acceleration value G output from the G sensors 14A, 14B, and 14C necessary for controlling the airbag 7 is used, existing components can be used effectively, and the occupant detection device 10 is erroneously determined at low cost. Can be prevented.

  Examples of the above-described embodiment will be described below. Note that the same or equivalent portions as those described in the embodiment will be described with the same reference numerals.

  In the above embodiment, the configuration in which all the G sensors 14A, 14B, and 14C are provided in the airbag control unit 11 has been described. However, in this embodiment, an acceleration sensor connected to the CAN 18 as a control communication network is used. The case where it does is demonstrated.

  As shown in FIG. 3, a G sensor 19 that detects acceleration in the X-axis direction and a G sensor 20 that detects acceleration in the Y-axis direction are connected to the airbag control unit 16 of the present embodiment by a CAN 18.

  For example, the airbag 7 is controlled by a G sensor 19 that detects acceleration in the vehicle longitudinal direction (X-axis direction) attached to the crash zone in order to detect a frontal collision, and is attached to the side of the vehicle body for side collision. The G sensor 20 that detects the acceleration in the vehicle width direction (Y-axis direction) is used.

  Since these G sensors 19 and 20 attached to the outside are connected to the airbag control unit 16 by the CAN 18 and periodically transmit the detected acceleration value G to the airbag control unit 16 by CAN communication. Transmission of these acceleration values G to the occupant determination unit 12 can be easily performed without providing a new interface.

  Thus, there is no need to newly provide an acceleration sensor or a new interface for establishing a connection with the acceleration sensor, and existing components can be used effectively, so the occupant detection device 10 can be used at low cost. A misjudgment can be prevented.

  Other configurations and operational effects are substantially the same as those in the above-described embodiment, and thus description thereof is omitted.

  Although the best embodiment of the present invention has been described in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and design changes that do not depart from the gist of the present invention are possible. Are included in the present invention.

  For example, in the embodiment or the example, the load sensor 4 is used as the physique measuring unit. However, the present invention is not limited to this, and a unit that measures the occupant pressure by arranging a pressure sensor in the seat cushion portion 1a. If the seat cushion portion 1a has a pressure-sensitive sensor and detects the size of the occupant's buttocks and the sum of the pressures of the occupant, the measured value may change as the occupant's posture changes. Can be applied.

  Further, in the above-described embodiment or example, the case where the airbag 7 is controlled as an occupant protection device has been described. However, the present invention is not limited to this. You can also.

It is a block diagram explaining the structure of the passenger | crew detection apparatus of the best embodiment of this invention. It is the flowchart which showed the flow of the process of a passenger | crew detection apparatus. It is a block diagram explaining the structure of the passenger | crew detection apparatus of an Example. It is a perspective view explaining the structure of the conventional passenger | crew detection apparatus. It is a block diagram explaining the structure of the conventional passenger | crew detection apparatus.

Explanation of symbols

1 Seat 4 Load sensor (physique measuring means)
7 Airbag (occupant protection device)
DESCRIPTION OF SYMBOLS 10 Occupant detection apparatus 11, 16 Airbag control part 12 Occupant determination part 14A-14C G sensor (acceleration sensor)
15 EEPROM (storage unit)
19-21 G sensor (acceleration sensor)

Claims (1)

It has an occupant determination unit that determines an occupant state by comparing an output value measured by a physique measuring means with respect to an occupant seated on a vehicle seat and a preset threshold value, and the determination result by the occupant determination unit is An occupant detection device used to control an occupant protection device,
The determination result is stored in a storage unit, and when an acceleration value output from an acceleration sensor used for controlling the occupant protection device exceeds an acceleration threshold, the determination result stored in advance is used, and an acceleration threshold An occupant detection device that newly determines the occupant state in the following cases.

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