1. Field of the Invention
The present invention relates to an occupant detecting apparatus for detecting an occupant seated on a passenger seat of a vehicle with an airbag.
2. Description of the Related Art
In a vehicle, an airbag is provided in a driver seat in order to alleviate the impact of a collision. Generally, since an adult is seated on the driver seat, when any occupant seated on the driver seat is detected, the inflation of the airbag is always permitted.
On the other hand, an airbag is also provided in a front passenger seat. In this case, since a child or an infant as well as an adult may be seated on the front passenger seat, the permission for the inflation of the airbag depends upon an occupant seated on the front passenger seat. Note that, when a child or an infant is seated on the front passenger seat, if the airbag is inflated, the face of the child or infant is damaged by the inflation of the airbag, which invites a more serious result. Therefore, when a child or an infant is seated on the front passenger seat, the inflation of the airbag is not permissible.
In order to determine whether an occupant seated on the front passenger seat is an adult or a child (infant), occupant detecting apparatuses have been developed. As a result, only when an occupant seated on the front passenger seat is an adult, is the inflation of the airbag permitted to protect a child (infant) from being seriously injured.
A first prior art occupant detecting apparatus is constructed by a load sensor provided on a bottom part of a front passenger seat (see: JP-A-9-207638 and JP-A-10-297334). For example, if the output voltage of the load sensor is higher than a reference value, it is determined that an adult is seat on the front passenger seat. Otherwise, it is determined that a child or an infant is seated on the front passenger seat. Note that it is possible to compare the output voltage of the load sensor with two reference values.
In the above-described first prior art occupant detecting apparatus, however, when a large luggage is seated on the front passenger seat, such a large luggage is considered as an adult to permit the inflation of the airbag. That is, it is impossible to discriminate an adult from a large luggage.
A second prior art occupant detecting apparatus is constructed by electric field sensors (see: JP-A-11-78655). This will be later explained in detail. That is, the electric field sensors can detect a human body, whether it is an adult, a child or an infant.
In the above-described second prior art occupant detecting apparatus, however, the electric field sensors detect a wet seat with no occupant as a human body to permit the inflation of the airbag.
Thus, both of the first and second prior art occupant detecting apparatuses are inferior in the detection accuracy.
It is an object of the present invention to provide an occupant detecting apparatus capable of improving the detection accuracy.
Another object is to provide an occupant detecting apparatus used in controlling the inflation of a side-airbag.
According to the present invention, in an occupant detecting apparatus for detecting an occupant seated on a passenger seat of a vehicle with an airbag for the occupant, a load sensor is provided in a bottom part of the seat. A plurality of first electric field sensors are provided in the bottom part of the seat, and a plurality of second electric field sensors are provided in a rear part of the seat. An airbag inflating permission control unit permits inflation of the airbag in accordance with output signals of the load sensor and the first and second electric field sensors.
Also, in an occupant detecting apparatus for detecting an occupant seated on a passenger seat of a vehicle with an airbag for the occupant, a plurality of first electric field sensors are provided in the bottom part of the seat, and a second electric field sensor is provided in a rear part of the seat. An airbag inflating permission control unit permits inflation of the airbag in accordance with output signals of the first and second electric field sensors.
Further, in an occupant detecting apparatus for detecting an occupant seated on a passenger seat of a vehicle with a side-airbag for the occupant, a load sensor is provided in a bottom part of the seat, and an electric field sensor is provided in a rear part of the seat on a side of the side-airbag. An airbag inflating permission control unit permits inflation of the side-airbag in accordance with output signals of the load sensor and said electric field sensor.
The present invention will be more clearly understood from the description set forth below, as compared with the prior art, with reference to the accompanying drawings, wherein:
Before the description of the preferred embodiments, a prior art electric field sensor will be explained with reference to
As illustrated in
As illustrated in
In
A load sensor 2 formed by a strain gauge or a pressure sensor is provided between the bottom part 11 of the seat 1 and a vehicle floor (not shown), to measure the weight of an occupant seated on the seat 1.
Five antenna electrodes 3-1, 3-2, 3-3, 3-4 and 3-5 for electric field sensors are provided in the bottom part 11 of the seat 1, and five antenna electrodes 3-6, 3-7, 3-8, 3-9 and 3-10 for electric field sensors are provided in the rear part 12 of the seat 1.
The load sensor 2 and the antenna electrodes 3-1, 3-2, . . . , 3-10 are connected by a wire harness to a control unit 4 which also receives an output signal from an acceleration sensor 5 to control an airbag inflator 6 for inflating an airbag. For example, the inflator 6 includes a source of gun powder, an igniter for igniting the gun powder of the gun powder source, and a generator triggered by the ignition of the gun powder for generating pressurized hot gas. That is, when the inflator 6 is driven by the control unit 4, pressurized hot gas is injected into the airbag 7, thus rapidly inflating the airbag 7.
In
Also, the control unit 54 is formed by a high frequency oscillator 4-2, a resistor 4-3, a voltage buffer 4-4 and a detector 4-5 corresponding to the high frequency oscillator 101, the resistor 102, the voltage buffer 103 and the detector 104, respectively, of
Further, an A/D converter 4-9 performs an A/D conversion upon the output signal of the acceleration sensor to generate a digital output acceleration voltage VACC. An input/output interface 4-10 is connected to the airbag inflator 6.
The A/D converters 4-1, 4-8 and 4-9 and the input/output interface 4-10 are connected to a central processing unit (CPU) 4-11 for controlling the entire system, a read-only memory (ROM) 4-12 for storing programs and fixed data and a random access memory (RAM) for storing temporary data. The CPU 411 is also connected to the selectors 4-6 and 4-7.
The airbag inflating operation of the control unit 4 (the CPU 4-11) of
First, at step 401, the CPU 4-11 fetches the digital output acceleration voltage VACC from the A/D converter 4-9.
Next, at step 402, it is determined whether the digital output acceleration voltage VACC is higher than a reference vale VACCREF, i.e., whether or not a collision has occurred on the front or rear side of the vehicle. Only when VACC>VACCREF) does the control proceed to step 403. Otherwise, the control proceeds directly to step 405.
At step 403, it is determined whether an airbag inflating permission flag FX is “1” or “0”. Note that the setting and resetting of the inflation permission flag FX will be explained later. Only when FX is “1”, does the control proceed to step 404 which drives the airbag inflator 6, thus inflating the airbag 7. Otherwise, the control proceeds directly to step 405.
The routine of
An operation of calculating the airbag inflating permission flag FX of
First, at step 501, the CPU 4-11 fetches the digital load voltage VLOAD from the A/D converter 4-1.
Next, at step 502, the CPU 4-11 fetches the digital output electric field voltage VEF (i) from the A/D converter 5-8 where i is 1 to 5. In this case, the digital output electric field voltage VEF (i) is obtained when the CPU 4-11 operates the selectors 4-6 and 4-7 so that the antenna electrode 3-i is connected between the resistor 4-3 and the voltage buffer 4-4.
Next, at step 503, an average value VEFAV1 is calculated by
VEFAV1←(VEF(1)+VEF(2)+ . . . +VEF(5))/5
Next, at step 504, the CPU 4-11 fetches the digital output electric field voltage VEF (i) from the A/D converter 5-8 where i is 6 to 10.
Next, at step 505, an average value VEFAV2 is calculated by
VEFAV2←(VEF(6)+VEF(7)+ . . . +VEF(10))/5
Next, at step 506, the airbag inflating permission flag FX is calculated in accordance with the values VLOAD, VEFAV1, and VEFAV2, using a table as shown in
a high state (VLOAD>VLOADREF1);
a medium state (VLOAD2<VLOAD≦VLOADREF1); and
a low state (0≦VLOAD≦VLOAD2)
Also, it is determined whether or not VEFAV1 is higher than a reference value VEFAVREF1, and it is determined whether or not VEFAV1 is higher than a reference value VEFAVREF2 (≦VEFAVREF1). As a result, there are three states of the voltage VEFAV1:
a high state (VEFAV1>VEFAVREF1)
a medium state (VEFAVREF2<VEFAV1≦VEFAVREF1); and
a low state (0≦VEFAY1≦VEFAVREF2).
Further, it is determined whether or not VEFAV1 is higher than the reference value VEFAVREF1, and it is determined whether or not VEFAV2 is higher than the reference value VEFAVREF2. As a result, there are three states of the voltage VEFAV2:
a high state (VEFAV2>VEFAVREF1);
a medium state (VEFAVREF2<VEFAV2≦VEFAVREF1); and
a low state (0≦VEFAV2≦VEFAVREF2)
Then, “0” or “1” is allocated to the airbag inflating permission flag FX in accordance with the table of
For example, as illustrated in
As illustrated in
As illustrated in
As illustrated in
As illustrated in
As illustrated in
As illustrated in
As illustrated in
Then, the routine of
In the above-described first embodiment, a plurality of electric field sensors other than the five electric field sensors can be provided on the bottom part 11 of the seat 1, and also, a plurality of electric field sensors other than the five electric field sensors can be provided on the rear part 12 of the seat 1. Also, the reference values VEFAVREF1 and VEFAVREF2 can be different values for the average voltages VEFAV1 and VEFAV2.
In
In
The airbag inflating operation of the control unit 4 (the CPU 4-11) of
An operation of calculating the airbag inflating permission flag FX of
First, at step 1001, the CPU 4-11 fetches the digital output electric field voltage VEF (i) from the A/D converter 5-8 where I is 1 to 5. In this case, the digital output electric field voltage VEF (i) is obtained when the CPU 5-11 operates the selectors 5-6 and 5-7 so that the antenna electrode 3-i is connected between the resistor 4-3 and the voltage buffer 4-4.
Next, at step 1002, an average value VEFAV is calculated by
VEFAV←(VEF(1)+VEF(2)+ . . . +VEF(5))/5
Next, at step 1003, the CPU 4-11 fetches the digital output electric field voltage VEF (10) from the A/D converter 5-8.
Next, at step 1004, the airbag inflating permission flag FX is calculated in accordance with the values VLOAD, VEFAV) and VEF(10), using a table as shown in
a high state (VEFAV>VEFAVREF1);
a medium state (VEFAVREF2<VEFAV≦VEFAVREF1); and
a low state (0≦VEFAV≦VEFAVREF2).
Further, it is determined whether or not VEF(10) is higher than the reference value VEFREF. As a result, there are two states of the voltage VEFAV2):
a high state (VEF(10)>VEFREF); and
a low state (0≦VEF(10)≦VEFREF).
Then, “0” or “1” is allocated to the airbag inflating permission flag FX in accordance with the table of
For example, as illustrated in
As illustrated in
As illustrated in
As illustrated in
Then, the routine of
In the above-described second embodiment, a plurality of electric field sensors other than the five electric field sensors can be provided on the bottom part 11 of the seat 1.
In
A load sensor 2 formed by a strain gauge or a pressure sensor is provided between the bottom part 11 of the seat 1 and a vehicle floor (not shown), to measure the weight of an occupant seated on the seat 1.
An antenna electrode 3′ for an electric field sensor is provided on the side of the rear part 12 of the seat 1.
The load sensor 2 and the antenna electrode 3′ are connected by wire harness to a control unit 4 which also receives an output signal from a traverse acceleration sensor 5′ to control a side-airbag inflator 6′ for inflating a side-airbag 7′. That is, when the inflator 6′ is driven by the control unit 4, pressurized hot gas is injected into the side-airbag 7′, thus rapidly inflating the side-airbag 7′.
Note that the side-airbag 7′ is located next to the antenna electrode 3′.
In
The side-airbag inflating operation of the control unit 4 (the CPU 4-11) of
First, at step 1501, the CPU 4-11 fetches the digital output acceleration voltage VACC′ from the A/D converter 4-9.
Next, at step 1502, it is determined whether the digital output acceleration voltage VACC′ is higher than a reference vale VACCREF, i.e., whether or not a collision has occurred on the traverse side of the vehicle. Only when VACC′>VACCREF′, does the control proceed to step 1503. Otherwise, the control proceeds directly to step 1505.
At step 1503, it is determined whether a side-airbag inflating permission flag FX′ is “1” or “0”. Note that the setting and resetting of the inflation permission flag FX′ will be explained later. Only when FX′ is “1”, does the control Proceed to step 1504 which drives the side-airbag inflator 6′, thus inflating the airbag 7′. Otherwise, the control proceeds directly to step 1505.
The routine of
An operation of calculating the side-airbag inflating permission flag FX′ of
First, at step 1601, the CPU 4-11 fetches the digital load voltage VLOAD from the A/D converter 4-1.
Next, at step 1602, the CPU 4-11 fetches the digital output electric field voltage VEF from the A/D converter 48.
Next, at step 1603, the side-airbag inflating permission flag FX′ is calculated in accordance with the values VLOAD and VEF using a table as shown in
a high state (VLOAD>VLOADREF1);
a medium state (VLOADREF2<VLOAD−VLOADREF1); and
a low state (0≦VLOAD≦VLOADREF2)
Also, it is determined whether or not VEF is higher than a reference value VEFREF1, and it is determined whether or not VEF is higher than a reference value VEFREF2 (<VEFREF1). As a result, there are three states of the voltage VEF:
a high state (VEF>VEFREF1);
a medium state (VEFREF2<VEF≦VEFREF1); and
a low state (0≦VEF≦VEFREF2).
Then, “0” or “1” is allocated to the side-airbag inflating permission flag FX′ in accordance with the table of
For example, when an adult is surely seated on the seat 1, the voltage VLOAD is high (>VLOADREF), so that the side-airbag inflating permission flag FX′ is set (FX=“1”) regardless of the voltage VEF.
As illustrated in
As illustrated in
As illustrated in
Then, the routine of
In the above-mentioned embodiments, the reference values such VLOADREF1, VLOADREF2, VEFAVREF1, VEFAVREF1, VEFREF1 and VEFREF2 can be corrected as occasion demands. For example, when no object is seated in the seat 1, the driver initiates a flowchart as illustrated in
As illustrated in
Also, the antenna electrodes 3-1, 3-2, . . . , 3-5 of
In the above-described first and second embodiments, although the averge value of the output signals of the electric field sensors is calculated, the permission flag can be calculated in accordance with the pattern of the output signals of the electric field sensors.
Also, the present invention can be applied to a rear passenger seat.
As explained hereinabove, according to the present invention, since a plurality of electric field sensors are provided in a passenger seat and the presence or absence of an occupant in the seat is determined in accordance with a logic processing of the output signals of the electric field sensors, the detection accuracy of an occupant in the seat can be improved.
Also, the presence or absence of an occupant in the seat is determined in accordance with the combination of an output signal of a load sensor provided in the seat with the output signals of the electric field sensors, the detection accuracy of an occupant can be further improved.
Number | Date | Country | Kind |
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2000-299047 | Sep 2000 | JP | national |
This application is a Divisional of U.S. patent application Ser. No. 09/962,356 filed on Sep. 26, 2001 now U.S. Pat. No. 6,684,973. The entire contents of the above-identified application is hereby incorporated by reference.
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Number | Date | Country |
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Number | Date | Country | |
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20040075259 A1 | Apr 2004 | US |
Number | Date | Country | |
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Parent | 09962356 | Sep 2001 | US |
Child | 10682991 | US |