JP4337043B2 - Occupant detection system - Google Patents

Description

  The present invention detects a load acting on a vehicle seat by a sensor, and based on the output of the sensor, the seating state is a non-sitting state where no occupant is seated or a seating state where the occupant is seated The present invention relates to an occupant detection system.

An example of a vehicle equipment for improving safety in a collision accident is an airbag. The airbag includes an airbag that is deployed from the front of the seat and a side airbag that is deployed from the side of the seat in the event of a collision. In the airbag deployment control, the deployment speed is adjusted or the operation is prohibited depending on whether the occupant seated on the seat is an adult or a child. In order to ensure safety, it is necessary to accurately determine whether the occupant seated on the seat is an adult or a child.
The technology for determining the occupant seated on the seat includes, for example, a sensor that detects a load acting on the seating surface of the seat, and the occupant seated on the seat based on the load detected by the sensor. There is an occupant detection system that determines whether a person is an adult or a child (see, for example, Patent Document 1).

JP 2003-276557 A

However, Patent Document 1 does not consider the movement and posture change of the occupant sitting on the seat. For example, when an occupant seated on a seat is an adult and the adult changes posture, the load acting on the seat decreases depending on the posture, and the child is seated even though the adult is seated. There is a possibility that a malfunction such as erroneous determination that the child is in a sitting state.
On the other hand, for example, the state distribution load used for the determination from the adult seated state to the child seated state is different from the state distribution load used for the determination from the child seated state to the adult seated state, thereby reducing erroneous determination. There is something to make. However, for example, when a light adult takes a weight loss posture, there is a possibility that it is erroneously determined that the child is seated. Furthermore, the state distribution load used for the determination from the child seating state to the adult seating state is set to be large so that it is difficult to switch the determination from the child seating state to the adult seating state once it is erroneously determined as the child seating state. In such a case, the erroneous determination is maintained, and there is a possibility that the determination cannot be returned.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an occupant detection system that can prevent erroneous determination, facilitate determination return, and more accurately determine an occupant seated on a seat. It is in.

FEATURES configuration of an occupant detection system according to the present invention for achieving the object of this is, the load acting on the seat of the vehicle detected by the sensor, the output of the sensor, the seating state of the seat, the passenger An occupant detection system for determining whether a non-sitting state or a sitting state where an occupant is seated, wherein the seating state is a state in which a load equal to or higher than a preset first state distribution load is detected. Is divided into a first seating state and a second seating state in which a load less than the first state distribution load is detected , and when the occupant is seated, the first state is detected by the sensor. It is determined that the first seating state has been established by detecting a load greater than or equal to the distribution load and maintaining a load greater than or equal to the first state distribution load for a preset first state distribution time. the by said sensor first Jo A load less than the distribution load is detected, and a load less than the first state distribution load is maintained for a preset second state distribution time, and is determined to be in the second seating state. When the non-sitting state is determined and then the first sitting state is further determined, the sensor detects a load lower than the first state change load smaller than the first state distribution load. It is, and will be determined that the the first load falls below a state change load becomes the second seating state when it is maintained during the second state sorting the first state change time longer than the time In the point.
Normally, since the occupant rarely takes a load-reducing posture while riding, the determination of the sitting state is relatively reliable when the occupant is seated, i.e., when the non-sitting state is changed to another sitting state. It is considered high. Therefore, as in this feature configuration, the state distribution load and the state distribution are controlled so that the seating state initially set when the occupant is seated is further prevented from being changed to the non-sitting state and the other seating state. Changing the time makes it difficult to change from a highly reliable seating state to another seating state. As a result, the determination reliability can be further improved.
In addition, depending on the seating state initially set when the occupant is seated, the state distribution load and state distribution time set between the seating state and other states are appropriately changed. Even when the state is changed to another seating state, a plurality of different state distribution loads and state distribution times can be set. Thereby, it is possible to deal with the diversity of the manner of changing the posture of the occupant, and the reliability of the determination can be improved.
Moreover, when using the result of these determinations for control of safety equipment etc., control of these safety equipment etc. can be implemented more appropriately, and a passenger | crew's safety can be improved.

According to another characteristic configuration, after the second seating state is determined, and further after the first seating state is determined, the sensor is smaller than the first state distribution load by the sensor. A second state change in which a load lower than a second state change load greater than the first state change load is detected and a load lower than the second state change load is longer than the second state distribution time When it is maintained for a time, it is determined that the second seating state is reached.

Further, another feature configuration, the first seating state is adults sitting state, lies in the second seating state is a child sitting state.
In control of safety equipment such as an air bag, control is generally performed depending on whether the person is an adult or a child. Therefore, it can respond to these safety equipment etc. by comprising like this characteristic composition.

According to the above-described feature configuration, when the current determination is the adult seated state, the state change load and the state change time are reset so that it is difficult to switch from the adult seated state to the child seated state. Thus, for example, when the occupant seated on the seat is an adult, the child is seated even if the adult takes a load reducing posture after sitting on the seat and the load acting on the seat decreases. It becomes difficult to be judged. Therefore, the misjudgment can be effectively prevented by configuring like this feature configuration.

Further , according to the above-described feature configuration , for example, when the occupant seated on the seat is a child, the child takes a posture to concentrate the load locally after sitting on the seat, and is erroneously determined as an adult seated state. If the Ru Oh. Here, injuries caused by airbags often occur when the occupant is a child or an infant. For this reason, in the airbag control, different deployment control is performed depending on whether the occupant is an adult or a child, thereby reducing the accident of injury to the child. Therefore, in the event of a collision, if the passenger is erroneously determined to be an adult even though it is a child and air bag control for adults is performed, the safety of the child seated on the seat is impaired.
Therefore, as in this feature configuration, after the child seated state is changed to the adult seated state, the state change load and the state change time are reset so that it is easy to return to the child seated state. Here, the second state change load is set to a higher value, that is, a value larger than the first state change load and smaller than the state distribution load in order to facilitate the determination return to the child sitting state. . Thereby, it becomes easy to change to the child sitting state, and the determination return to the child sitting state is facilitated. Therefore, by configuring as in the present feature configuration, it is possible to facilitate the return of determination even if an erroneous determination is made.

Embodiments of an occupant detection system according to the present invention are described below with reference to the drawings.
FIG. 1 is a configuration diagram of an occupant detection system according to the present invention and its periphery. The occupant detection system according to the present invention is constructed in an ECU 1 (Electronic Control Unit), receives load data from a sensor 3 that detects a load acting on a vehicle seat 2, and sends a determination result to an airbag control circuit 8. It is configured to output. The sensors 3 are provided at at least four locations on the left and right of the front of the seat 2 and on the left and right of the rear, and output load data in the form of voltage.

  The ECU 1 includes a sensor signal input circuit 4, a CPU 5 (Central Processing Unit), a determination output circuit 6, and a power supply circuit 7.

  The sensor signal input circuit 4 is connected to the sensor 3 and the CPU 5, receives load data in the form of voltage from the sensor 3, performs A / D conversion, and outputs it to the CPU 5. The sensor signal input circuit 4 is provided for each sensor 3. In this embodiment, four sensor signal input circuits 4 are provided for each of the sensors 3a to 3d.

  The CPU 5 receives the load data from the sensor signal input circuit 4, and whether the load acting on the seat 2 corresponds to an empty state where the occupant is not seated (non-sitting state) or a seated state where the occupant is seated. Determine. The seating state is divided into a plurality of seating states according to a preset state distribution load. The seating state of this embodiment includes a child seating state in which a child is seated and an adult in which an adult is seated. The seating state is set.

  Here, the CPU 5 determines the empty state and the sitting state corresponding to the detected load using the state distribution load and the state distribution time. Specifically, when the occupant is seated, the load of the sensors 3a to 3d corresponds to one of a plurality of seating states, and this state is maintained for a state distribution time set in advance for the seating state, so that the seating is performed. It is determined that a state has been reached. Furthermore, in the present embodiment, a switching flag indicating a change state of the seating state is set. This switch flag is set when there is a high possibility that the occupant seated in the seat 2 is an adult. The seating state is changed from the child seated state to the adult seated state, and the occupant seated in the seat 2 may be a child. Clear if is high.

The setting of the state distribution load and the state distribution time will be described below.
A state distribution load A is set as a state distribution load when the seating state is changed from the empty state and the child seating state to the adult seating state. In addition, the state distribution load C is set as the state distribution load when changing from the empty state to the child sitting state, and the state distribution load when changing from the adult sitting state and the child sitting state to the empty state. Has been. Here, the state distribution load C is a child's prescribed maximum load. At this time, a state distribution time T1 is set for the change to the adult sitting state, a state distribution time T2 for the change to the child sitting state, and a state distribution time T3 for the change to the empty state.

  When the seating state is changed from the adult seating state to the child seating state, the state change load and the state change time are selected according to the switching flag. When the switching flag is set, a lower state change load X is set, and a state change time TX longer than the state distribution time T2 is set. This makes it difficult to change the seating state from the adult seating state to the child seating state, and prevents erroneous determination. When the switching flag is cleared, a state change load Y larger than the state change load X is set, and a state change time TY shorter than the state distribution time T2 is set. This facilitates changing the sitting state from the adult sitting state to the child sitting state, and facilitates the determination return to the child sitting state.

  The determination of the occupant by the CPU 5 will be described with reference to FIGS. Here, FIG. 2 is a flowchart showing the determination procedure of the occupant, and FIG. 3 shows the relationship between the load variation and the determination when the seating state is changed from the empty state to the child seating state. FIG. 4 shows the relationship between load variation and determination when the child seated state is changed to the adult seated state.

  As shown in FIG. 2, the CPU 5 obtains and sums the values of the loads detected by the sensors 3 a to 3 d based on the load data input from the sensor signal input circuit 4 at regular time intervals. The load of the seated occupant is obtained (step # 101). Then, it is detected whether the current determination is an empty state, a child sitting state or an adult sitting state (step # 102).

If the current determination is empty in step # 102, the process proceeds to step # 103. As shown in FIG. 3, when the load calculated in step # 101 is equal to or greater than the state distribution load A, and this continues for the state distribution time T1 or longer, it is determined that the person is in the adult sitting state (step # 104). ). Further, a switching flag is set (step # 105). When the seating state is first changed from an empty state to another seating state, it is during the seating of the occupant and it is unlikely that the occupant will take a load-reducing posture. When the seating state is changed, it is considered that there is a high possibility that the passenger sitting on the seat 2 is an adult.
Otherwise, the process proceeds to step # 106. When the load calculated in step # 101 is equal to or greater than the state distribution load C and less than the state distribution load A, and this continues for the state distribution time T2 or more, it is determined that the child is seated (step # 107). . Otherwise, the process proceeds to step # 120.

In step # 102, if the current determination is the child seated state, the process proceeds to step # 108. As shown in FIG. 4, when the load calculated in step # 101 is equal to or greater than the state distribution load A and continues for the state distribution time T1 or longer, it is determined that the person is in the adult sitting state (step # 109). ). Further, the switching flag is cleared (step # 110). Note that it is considered that the determination of the adult seated state is highly likely to be erroneously determined by pressing the child seat 2 or the like. For this reason, by clearing the switching flag, it is easy to change from the adult seated state to the child seated state, and the determination return is facilitated.
Otherwise, the process proceeds to step # 111. When the load calculated in step # 101 is less than the state distribution load C and this is continuous for the state distribution time T3 or more, it is determined that the state is empty (step # 112). Otherwise, the process proceeds to step # 120.

  In step # 102, when the current determination is the adult seated state, the process proceeds to step # 113. If the switching flag is set in step # 113, the process proceeds to step # 114. When the switching flag is set, determination is made based on the state change load X and the state change time TX so that the sitting state is hardly changed from the adult sitting state to the child sitting state. In step # 114, as shown in FIG. 3, when the load calculated in step # 101 is greater than or equal to the state distribution load C and less than the state change load X, and this continues for the state change time TX or longer, the child sitting state Is determined (step # 115), and the switching flag is cleared (step # 116). Otherwise, the process proceeds to step # 118.

  If the switching flag is cleared in step # 113, the process proceeds to step # 117. When the switching flag is cleared, the determination is made based on the state change load Y and the state change time TY so that the sitting state can be easily changed from the adult sitting state to the child sitting state and the determination can be easily returned. In step # 117, as shown in FIG. 4, when the load calculated in step # 101 is greater than or equal to the state distribution load C and less than the state change load Y, and this continues for the state change time TY or more, the child sitting state Is determined (step # 115), and the switching flag is cleared (step # 116). Otherwise, the process proceeds to step # 118.

  In step # 118, when the load calculated in step # 101 is less than the state distribution load C and this continues for the state distribution time T3 or more, it is determined that the state is empty (step # 119). Otherwise, the process proceeds to step # 120. And CPU5 of this embodiment performs determination according to the passenger | crew's seating state to the seat 2 by repeatedly implementing step # 101 thru | or # 120 mentioned above for every fixed time.

  The determination output circuit 6 acquires a determination result from the CPU 5 when the determination is performed in the CPU 5 or when the sitting state is changed. And the determination result is output with respect to the apparatus which utilizes the said determination results, such as the airbag control circuit 8, according to the aspect of the said apparatus.

  The airbag control circuit 8 receives an output signal from the determination output circuit 6 and performs airbag deployment control based on the determination result of the ECU 1. Here, in addition to a normal airbag, a side airbag, a curtain airbag, and the like are provided, and the airbag control circuit 8 does not deploy the side airbag when, for example, a collision accident occurs or a child is seated. Thus, safety is ensured by controlling the deployment of the airbag in accordance with the adult sitting state and the child sitting state.

In the present embodiment, the child sitting state and the adult sitting state are set as the sitting state, but the present invention is not limited to this. Set an appropriate number of seating states according to the mode of the device using the determination result, such as airbag control, etc., and according to the setting of the seating state, an appropriate state distribution load and state distribution time, and Set the state change load and state change time.
Further, in the present embodiment, between the adult sitting state and the child sitting state, the state distribution load and the state that are different between the change from the child sitting state to the adult sitting state and the change from the adult sitting state to the child sitting state When changing load is set, but when more seating states are set, when changing from one of the empty state and multiple seating states to another empty state and multiple seating states, a plurality of similarly different states A distribution load and a state change load may be set, or only a state distribution load may be set for a part. Appropriate state distribution load and state distribution time, and state change load and state change time are set so as to prevent erroneous determination and facilitate return determination from erroneous determination.

Occupant detection system according to the present invention and its surrounding configuration diagram Flow diagram of occupant detection system according to the present invention Relationship diagram between load fluctuation and determination of occupant detection system according to the present invention Relationship diagram between load fluctuation and determination of occupant detection system according to the present invention

1 ECU
2 Sheet 3 Sensor 4 Sensor signal input circuit 5 CPU
6 Judgment Output Circuit 7 Power Supply Circuit 8 Airbag Control Circuit

Claims (3)

A load acting on the vehicle seat is detected by a sensor, and from the output of the sensor, it is determined whether the seating state of the seat is a non-sitting state where no occupant is seated or a seating state where the occupant is seated An occupant detection system,
The seating state is a state in which a first seating state in which a load equal to or higher than a preset first state distribution load is detected and a state in which a load less than the first state distribution load is detected. It is divided into the sitting state of
When the occupant is seated, a load greater than or equal to the first state distribution load is detected by the sensor, and a load greater than or equal to the first state distribution load is maintained for a preset first state distribution time. Thus, it is determined that the first seating state has been reached, a load less than the first state distribution load is detected by the sensor, and a load less than the first state distribution load is set in advance. When it is determined that the second seating state has been maintained by being maintained for the state distribution time,
After determining the non-sitting state, and further determining the first sitting state , the sensor detects a load lower than a first state change load smaller than the first state distribution load , and, occupant detection to determine the load below said first state change load becomes the second seating state when it is maintained during the second state sorting the first state change time longer than the time system. After determining the second seating state, after determining the second seating state, the sensor is smaller than the first state distribution load and larger than the first state change load by the sensor. When a load lower than the second state change load is detected and a load lower than the second state change load is maintained for a second state change time longer than the second state change time The occupant detection system according to claim 1, wherein the occupant detection system is determined to be in the second seating state. It said first seating state is adults seating state, the occupant detection system according to claim 1 or 2, wherein the second seating state is a child sitting state.

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