WO2001003978A1

WO2001003978A1 - Crew detection device and method

Info

Publication number: WO2001003978A1
Application number: PCT/JP1999/003741
Authority: WO
Inventors: Masahiro Nakamoto
Original assignee: Mitsubishi Denki Kabushiki Kaisha
Priority date: 1999-07-09
Filing date: 1999-07-09
Publication date: 2001-01-18

Abstract

An ultrasonic signal is radiated, a reflection signal of the ultrasonic signal is received, an amplitude of the reflection signal is measured for comparison with a threshold level, a majority processing is performed on a plurality of comparison results obtained at a signal processing unit (15) and any one of the comparison results is selected, thereby specifying the position of a crew member in the passenger seat next to the driver based on the selected comparison result. A change in an amplitude of a reflection signal is monitored to judge as to whether a human being or an object is present in the passenger seat.

Description

Specification

Occupant detection device and occupant detection method

Technical field

The present invention relates to an occupant detection device and an occupant detection method for detecting the position of an occupant in a passenger seat and the like.

Background art

FIG. 1 is a configuration diagram showing a conventional occupant detection device disclosed in, for example, Japanese Patent Application Laid-Open No. Hei 9-201293. In the figure, reference numeral 1 denotes a side surface of a dashboard 3 facing a passenger seat. An ultrasonic sensor that radiates the ultrasonic signal toward the passenger seat and receives the ultrasonic signal reflected to the occupant, 2 controls the transmission and reception of the ultrasonic signal by the ultrasonic sensor 1, The controller 3 detects the position of the occupant from the result of the transmission and reception of the ultrasonic signal, and 3 is the dashboard of the moving object.

Next, the operation will be described.

The ultrasonic sensor 1 emits an ultrasonic signal from the dashboard 3 toward the passenger seat under the instruction of the controller 2, and receives the ultrasonic signal reflected by the occupant.

The controller 2 measures the propagation time until the ultrasonic signal radiated from the ultrasonic sensor 1 is reflected by the occupant and returns to the ultrasonic sensor 1 a plurality of times.

Then, the controller 2 prevents the occupant from erroneously detecting the occupant's position due to the occupant temporarily taking a special posture (for example, when the occupant temporarily takes a special posture, an ultrasonic signal is generated). Without returning directly to the ultrasonic sensor 1, If it returns to the ultrasonic sensor 1 after being reflected by the interior of the vehicle, the position of the occupant is erroneously detected.) If the propagation time measured a plurality of times is the shortest, the propagation time is selected. The propagation time of is converted to the position of the occupant, and the position of the occupant is detected.

Since the conventional occupant detection device is configured as described above, erroneous detection of the occupant position can be prevented to some extent.For example, an occupant who is normally seated in the front passenger seat is temporarily There was a problem that if the vehicle was close to 3, there was a possibility that the position of the occupant would be erroneously detected (it could cause erroneous detection such as the occupant sitting near dashboard 3).

The present invention has been made to solve the above problems, and an occupant detection device and an occupant capable of accurately detecting the position of an occupant without being affected by a special posture taken by the occupant temporarily The purpose is to obtain a detection method. Disclosure of the invention

An occupant detection device according to the present invention includes a selection unit that executes a majority decision process on a plurality of comparison results obtained by a comparison unit and selects one of the comparison results.

This has the effect that the position of the occupant can be accurately detected even if the occupant temporarily takes a special posture.

The occupant detection device according to the present invention is configured to compare the amplitude measured by the measurement means with a plurality of threshold levels.

This has the effect that the position of the occupant can be accurately detected not only when the occupant is seated normally but also when the occupant is sitting on a rearward-facing child seat.

The occupant detection device according to the present invention includes a reflection signal measured by the measurement unit. A determination means is provided for monitoring a change in the maximum amplitude of the vehicle and determining whether the object present in the passenger seat is a human or an object.

As a result, there is an effect that it is possible to recognize whether the object existing in the passenger seat is a person or an object.

The occupant detection device according to the present invention, when determining that an object present in the passenger seat is an object, determines whether the object present in the passenger seat is a rearward facing child seat based on the propagation time of the maximum amplitude of the reflected signal. It is designed to classify whether there is no target in the system.

This has the effect of being able to recognize whether the object in the passenger seat is a backward-facing child seat or whether there is no object in the passenger seat.

The occupant detection device according to the present invention, when determining that the object existing in the passenger seat is a human, determines whether the object existing in the passenger seat is a standing child based on the propagation time of the maximum amplitude of the reflected signal. This classifies whether the person is seated normally.

This has the effect that it is possible to recognize whether the object existing in the front passenger seat is a standing child or whether the passenger is seated normally in the front passenger seat.

In the occupant detection method according to the present invention, a majority decision process is executed on a plurality of comparison results, and any one of the comparison results is selected.

The occupant detection method according to the present invention compares the amplitude of the reflected signal with a plurality of threshold levels.

As a result, the position of the occupant can be accurately determined not only when the occupant is seated normally but also when the occupant is seated on the rearward facing seat. There is an effect that can be detected.

An occupant detection method according to the present invention monitors a change in the maximum amplitude of a reflected signal to determine whether an object present in a passenger seat is a person or an object.

In the occupant detection method according to the present invention, when it is determined that the object existing in the passenger seat is an object, whether the object existing in the passenger seat is a rearward shielded seat based on the propagation time of the maximum amplitude of the reflected signal, It is designed to classify whether there is no target in the system.

As a result, it is possible to recognize whether the object existing in the passenger seat is a rearward facing child seat or whether there is no object existing in the passenger seat.

According to the occupant detection method of the present invention, when it is determined that the object existing in the passenger seat is a human, whether the object existing in the passenger seat is a standing child is determined based on the propagation time of the maximum amplitude of the reflected signal. This classifies whether the person is seated normally.

This has the effect that it is possible to recognize whether the object existing in the front passenger seat is a standing child or whether the passenger is seated normally in the front passenger seat. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a configuration diagram showing a conventional occupant detection device.

FIG. 2 is a configuration diagram showing an occupant detection device according to Embodiment 1 of the present invention.

FIG. 3 is a flowchart showing an occupant detection method according to Embodiment 1 of the present invention. It is a jar.

FIG. 4 is an explanatory diagram for explaining the processing of the signal processing section 15 (when the occupant is normally seated).

FIG. 5 is an explanatory diagram for explaining the processing of the signal processing unit 15 (when an occupant is present near the ultrasonic sensor 13).

FIG. 6 is an explanatory diagram showing a comparison result of the signal processing unit 15 (when the occupant is normally seated).

FIG. 7 is an explanatory diagram showing a comparison result of the signal processing unit 15 (when an occupant is present near the ultrasonic sensor 13).

FIG. 8 is a flowchart for explaining the operation of the signal processing unit 15. FIG. 9 is an explanatory diagram for explaining the majority decision processing.

FIG. 10 is a flowchart showing a method of calculating the distance data in the calculation unit 17.

FIG. 11 is a flowchart showing a method of detecting the position of the occupant in the arithmetic section 17.

FIG. 12 is a flowchart showing an occupant detection method according to Embodiment 2 of the present invention.

FIG. 13 is a flowchart showing a method of specifying the maximum amplitude in the arithmetic unit 17.

FIG. 14 is a flowchart showing a method of determining a person or an object in the arithmetic unit 17.

FIG. 15 is a flowchart showing the processing contents when it is determined that the object existing in the passenger seat is an object.

FIG. 16 is a flowchart showing the processing performed when it is determined that the object existing in the passenger seat is a human. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, in order to explain this invention in greater detail, the preferred embodiments of the present invention will be described with reference to the accompanying drawings. Embodiment 1

FIG. 2 is a configuration diagram showing an occupant detection device according to Embodiment 1 of the present invention, in which 11 is a dashboard of a moving object, 12 is a passenger seat of the moving object, and 13 is a passenger seat of the moving object. An ultrasonic sensor attached to the side of the dashboard 11 facing 1 2, radiating an ultrasonic signal toward the passenger seat 1 2, and receiving a reflected signal of the ultrasonic signal reflected to the occupant (Reception means) Reference numeral 14 denotes an occupant detection circuit including a signal processing unit 15, a memory 16, and a calculation unit 17.

Reference numeral 15 denotes a signal processing unit (measuring means, comparing means) which measures the amplitude of the reflected signal received by the ultrasonic sensor 13 and compares the amplitude of the reflected signal with a plurality of threshold levels. Is a memory for recording the comparison results of the signal processing unit 15, and 17 is a majority processing for multiple comparison results when the signal processing unit 15 performs the measurement processing multiple times and performs the comparison processing multiple times. A calculation unit (selecting means, position specifying means) for selecting one of the comparison results and specifying the position of the occupant in the passenger seat based on the selected comparison result.

FIG. 3 is a flowchart showing an occupant detection method according to Embodiment 1 of the present invention.

Next, the operation will be described.

First, the general operation of the occupant detection device will be described. First, the ultrasonic sensor 13 radiates an ultrasonic signal toward the passenger seat 12 (step ST 1), and receives a reflected signal of the ultrasonic signal. Then, the signal processing unit 15 The amplitude of the reflected signal received by the sensor 13 is measured, signal processing described later is performed (step ST 2), and the comparison result, which is the processing result, is recorded in the memory 16 (step ST 3).

When the processing in steps ST1 to ST3 is performed k times (steps ST4 and ST5), the arithmetic unit 17 executes majority processing on the k comparison results and executes any of the majority processing. The comparison result is selected (step ST6).

Then, using the selected comparison result, arithmetic unit 17 performs an arithmetic process described later (step ST7), and specifies the position of the occupant in the front passenger seat.

Next, a specific operation of the occupant detection circuit 14 will be described.

FIGS. 4 and 5 are explanatory diagrams for explaining the processing of the signal processing section 15.Particularly, FIG. 4 shows a case where the occupant is properly seated and FIG. 5 shows a standing child or a rearward child seat. As shown in the figure, the case where an occupant is present near the ultrasonic sensor 13 is shown, the horizontal axis represents the propagation time T, and the vertical axis represents the amplitude V of the reflected signal.

Here, in order to detect a reflected signal of a certain level or more at an arbitrary propagation time Τ, a plurality of threshold levels V th (from V1: 11111 1 11 to 11111 &) for comparing the reflected signal levels are provided. As shown in FIGS. 6 and 7, "1" is recorded in the memory 16 when ≥11 and "0" when V <Vth, as shown in FIGS.

The initial value T 0 of the propagation time T is the transmission start time of the ultrasonic signal, and the propagation time T end, which is the comparison end time of the reflected signal, is a preset value, and depends on the required maximum measurement distance. Set as appropriate. The required number of threshold levels Vth is set appropriately, with one level as the minimum number.

FIG. 8 is a flowchart for explaining the operation of the signal processing unit 15. Immediately after the ultrasonic signal is radiated, the signal processing unit 15 sets an initial value TO of the propagation time T (step ST11), and returns the ultrasonic signal. In addition to measuring the amplitude of the emission signal, the initial value V thmin is substituted for the threshold level V th (step ST 12).

Then, the signal processing unit 15 compares the amplitude V of the reflected signal with the threshold level Vth to determine whether the amplitude V of the reflected signal exceeds the threshold level Vth (step ST 13). ), If V≥Vth, "1" is recorded in the memory 16 (step ST14).

On the other hand, if V <Vth, "0" is recorded in the memory 16 (step ST15).

Next, the signal processing unit 15 raises the threshold level V th (step ST 16), and determines whether or not the comparison processing has been completed for all the threshold levels V th (step ST 16). ST 17).

If the comparison processing has not been completed for all the threshold levels V th, the process returns to step ST 13 to continue the comparison processing, and if the comparison processing has been completed, the propagation time T is counted up. Then, it is determined whether the propagation time T has reached the comparison end time T end (step ST 18) (step ST 19).

If the propagation time T has not reached the comparison end time T end, the process returns to step ST 12. If the propagation time T has reached the comparison end time T end, it is assumed that the signal processing has been terminated and Wait for the sound wave signal to be radiated, and perform the processing from step ST11.

In this way, when the signal processing unit 15 performs the signal processing of FIG. 8 a plurality of times, the arithmetic unit 17 performs a majority decision process as shown in FIG. When a special posture is taken, the night is canceled and the original position of the occupant can be detected.

Here, FIG. 10 is a flowchart showing a method of calculating the distance data in the arithmetic unit 17. The distance from the ultrasonic sensor 13 to the occupant is extremely large. Measure the propagation time Td from when the sound wave signal is emitted until the reflected signal reflected by the occupant is received (hereinafter referred to as distance conversion time Td), and convert the distance conversion time Td to distance You can ask for it.

Also, when the occupant is in a standing child or sitting on a rearward facing child seat, the occupant is extremely close to the ultrasonic sensor 13 and the ultrasonic sensor 13 itself is The aftershock waveform and the reflected signal overlap, and the aftershock time Tr may seem to be longer. In such a case, the aftershock time Tr is calculated to detect the occupant using the aftershock time Tr without using the distance conversion time Td.

More specifically, first, the arithmetic unit 17 determines which threshold level V th of the processing data of the comparison result of the signal processing unit 15 stored in the memory 16 (hereinafter referred to as processing data). Is selected, and the propagation time T is set to the initial value T 0 (step ST 21).

Then, when selecting the processing data to be used, the arithmetic unit 17 determines whether the processing data is “1” or “0”, and thereby determines the threshold level V th. It is determined whether or not a reflected signal having an amplitude larger than the above is received (step ST22).

If the processed data is "0", it is assumed that the aftershock of the ultrasonic sensor 13 has ended, and the value obtained by subtracting 1 from the propagation time T is recorded in the aftershock time Tr (step ST2). Five ) .

If the processed data is "1", it is assumed that the aftershock of the ultrasonic sensor 13 is still continuing, and the propagation time T is compared with the end time T end to determine whether the processed data has ended. (Step ST23).

If the processing data has not been completed, the propagation time T is counted up (step ST24), and the process returns to step ST22 to return to the processing data. If the evening has ended, the end time T end is recorded as the aftershock time Tr (step ST25).

Next, the arithmetic unit 17 determines whether or not the processing data has been completed (step ST26), and if completed, there is no reflected signal or the aftershock waveform continues. The end time T end is recorded in the distance conversion time T d (step ST 29).

If it is determined that the processing data has not been completed, the propagation time T is increased (step ST27), and it is determined whether or not the processing data is "1" (step ST27). 2 8).

If the processing time is "1", it is assumed that the reflected signal from the occupant has been detected, and the propagation time T is recorded in the distance conversion time Td (step ST29).

If the process is "0", it is assumed that there is no reflected signal, and the process returns to step ST26 to execute the same process.

When the aftershock time Tr and the distance conversion time Td are obtained in this way, the calculation unit 17 detects the position of the occupant based on the aftershock time Tr and the distance conversion time Td.

Here, FIG. 11 is a flowchart showing a method of detecting the position of the occupant in the arithmetic unit 17. First, the arithmetic unit 17 calculates the aftershock time T r and the aftershock time T based on the normal sitting time. Compare rc (step ST31).

If T r> T rc, it is determined that the occupant is located extremely close to the ultrasonic sensor 13 or that the occupant is sitting on the rearward facing seat (step ST 3 Four ) .

On the other hand, if Tr ≦ Trc, it is determined that there is no occupant near the ultrasonic sensor 13 and the distance conversion time Td is compared with the comparison value Tdc (step ST32). If T d ≤ T dc, it is determined that the occupant is seated in a standing child or a rearward facing child seat within a certain distance (step ST34), and T d> T dc In the case of, it is determined that the occupant is properly seated (step ST33).

As is clear from the above, according to the first embodiment, the majority processing is performed on a plurality of comparison results in the signal processing unit 15 to select one of the comparison results. Even if the occupant takes a temporary special posture, the occupant position can be accurately detected. Embodiment 2.

FIG. 12 is a flowchart showing an occupant detection method according to Embodiment 2 of the present invention. In the figure, the same reference numerals as in FIG. 3 denote the same or corresponding parts, and a description thereof will be omitted.

Each time the ST 41 processes the reflection signal, the ST 41 determines a person or an object existing in the passenger seat by capturing a change in the maximum amplitude of the reflection signal. Is a calculation step for executing the calculation processing to specify the position of the occupant.

Next, the operation will be described.

When the signal processing unit 15 records the processing data in the memory 16 in the same manner as in the first embodiment, the calculation unit 17 determines whether the object existing in the passenger seat is a human or an object. In order to determine the maximum amplitude, a process for obtaining the maximum amplitude of the reflected signal is executed.

Here, FIG. 13 is a flow chart showing a method of specifying the maximum amplitude in the arithmetic unit 17. First, the arithmetic unit 17 sets the maximum threshold level V thma X to the threshold level V th. (Step ST51), and transmit the aftershock time T rc determined based on normal seating. The seeding time T is set (step S S52), and the propagation time Τ is counted up (step SΤ53).

Next, the operation unit 17 determines whether or not the processing time at the threshold level Vth is "1" (step ST54).

If the processed data is "1", the threshold level Vth is recorded as the maximum amplitude Vmax, and the propagation time T is recorded as the propagation time Tmax of the maximum amplitude Vmax (step ST 5 8).

If the processing time is "0", it is determined whether or not the propagation time T has reached the comparison end time T End (step ST55).

If the propagation time T has not reached the comparison end time T en cU, the process returns to step ST53, and the steps following step ST53 are continued.

If the propagation time T has reached the comparison end time T End, it is determined whether or not the threshold level V th is equal to the minimum threshold level V th min (step ST 56).

If the threshold level Vth is not equal to the minimum threshold level Vthmin, the threshold level Vth is lowered (step ST57), and the process returns to step ST52.

When the threshold level Vth is equal to the minimum threshold level Vthmin, assuming that there is no reflected signal, the minimum threshold level Vthmin is recorded as the maximum amplitude Vmax, and the comparison end time T The end is recorded as the propagation time Tmax of the maximum amplitude Vmax (step ST58).

In this way, when the maximum amplitude Vmax and the propagation time Tmax of the maximum amplitude Vmax are recorded, the calculation unit 17 determines that the object existing in the passenger seat is a human based on the maximum amplitude Vmax and the propagation time Tmax. Or object I do.

Here, FIG. 14 is a flowchart showing a method of determining a person or an object in the calculation unit 17. First, the calculation unit 17 determines that the maximum amplitude Vmax is equal to the previous maximum amplitude Vmax. It is determined whether or not they match (step ST61), and it is also determined whether or not the propagation time Tmax matches the previous propagation time Tmax (step ST62).

If both the maximum amplitude Vmax and the propagation time Tmax match the previous time, the timer Tt for determining that the object existing in the passenger seat is an object is counted up (step ST63). Evening time Tt is compared with threshold Ttc for determination (step ST64).

In the case of T t ≥T t c, since the maximum amplitude Vmax and the propagation time Tmax have not changed for a certain period of time or more, it is determined that the target existing in the passenger seat is an object (step ST65).

On the other hand, if T t <T t c, the object in the passenger seat is moving, so it is determined that the object in the passenger seat is a human (step S T 67

) o

If it is determined in any of steps ST61 and ST62 that they do not match the previous time, the maximum amplitude Vmax or the propagation time Tmax is assumed to have changed, and the final setting time Tt is initialized. Return to value 0 (Step ST 6

6) The object existing in the passenger seat is determined to be a human (step S T 6

7).

If it is determined that the object present in the passenger seat is an object, the processing of steps ST 4 to ST 6 in FIG. 12 is not performed because there is no need to execute the majority decision processing in the evening. .

FIG. 15 is a flowchart showing the processing performed when it is determined that the object existing in the passenger seat is an object. If it is determined that the elephant is an object, the propagation time T max is compared with the comparison value Tmax X c 1 (step ST71).

If Tmax≤Tmaxc1, it is determined that the occupant is seated on the rearward facing child seat where an object exists near the ultrasonic sensor 13 (step ST72).

On the other hand, if Tmax> Tmaxc1, it is determined that the passenger seat is unmanned (step ST73).

Fig. 16 is a flowchart showing the processing performed when it is determined that the object present in the passenger seat is a human.The arithmetic unit 17 has determined that the object present in the passenger seat is a human. In the case, the propagation time Tmax is compared with the comparison value Tmaxx2 (step ST81).

If Tmax≤Tmaxx2, it is determined that a standing child exists near the ultrasonic sensor 13 (step ST82). On the other hand, if TmaX> TmaXc2, it is determined that the occupant is normally seated on the passenger seat (step ST83).

As is clear from the above, according to the second embodiment, a change in the maximum amplitude of the reflected signal is monitored to determine whether the object existing in the passenger seat is a human or an object. Therefore, it is possible to recognize whether the object existing in the passenger seat is a person or an object. Industrial applicability

As described above, the occupant detection device and the occupant detection method according to the present invention are suitable, for example, to be mounted on an airbag control device that controls a deployment range of an airbag in a passenger seat according to a position of an occupant. .

Claims

Range of request

1. Receiving means for radiating an ultrasonic signal and receiving a reflected signal of the ultrasonic signal, measuring means for measuring the amplitude of the reflected signal received by the receiving means, and amplitude measured by the measuring means The threshold level and

p blue

When the comparing means performs the measurement processing a plurality of times, and the comparing means performs the comparison processing a plurality of times, a majority decision processing is performed on the plurality of comparison results obtained by the comparing means. An occupant detection device comprising: selecting means for selecting the result of the comparison; and position specifying means for specifying the position of the occupant in the passenger seat based on the result of the comparison selected by the selecting means.

2. The occupant detection device according to claim 1, wherein the comparing means compares the amplitude measured by the measuring means with a plurality of threshold levels.

3. A determination means for monitoring a change in the maximum amplitude of the reflected signal measured by the measurement means and determining whether the object existing in the passenger seat is a human or an object is provided. The occupant detection device according to claim 1, wherein:

4. When the determination means determines that the object existing in the passenger seat is an object, it determines whether the object existing in the front passenger seat is a rearward seated sheet based on the propagation time of the maximum amplitude of the reflected signal. 4. The occupant detection device according to claim 3, wherein the presence or absence of the occupant is classified.

5. When the determination means determines that the object existing in the passenger seat is a human, the object existing in the passenger seat is determined based on the propagation time of the maximum amplitude of the reflected signal. 4. The occupant detection device according to claim 3, wherein the occupant detection device is configured to classify whether the vehicle is a swing child and whether the passenger is seated normally on the passenger seat.

6. When the ultrasonic signal is radiated and the reflected signal of the ultrasonic signal is received, the amplitude of the reflected signal is measured and compared with the threshold level, and the measuring process of the reflected signal is executed plural times. When the comparison process is executed a plurality of times, the majority process is performed on the plurality of comparison results, one of the comparison results is selected, and the position of the occupant in the passenger seat is specified based on the selected comparison result. Crew detection method.

7. The occupant detection method according to claim 6, wherein the amplitude of the reflected signal is compared with a plurality of threshold levels.

8. The occupant detection method according to claim 6, wherein a change in the maximum amplitude of the reflected signal is monitored to determine whether the object existing in the passenger seat is a human or an object.

9. When determining that the object in the passenger seat is an object, based on the propagation time of the maximum amplitude of the reflected signal, whether the object in the passenger seat is a backward facing seat sheet or whether there is no object in the passenger seat 9. The occupant detection method according to claim 8, wherein the occupant is classified.

10. When it is determined that the object in the front passenger seat is a human, whether the object in the front passenger seat is a snowfield or a normal seat in the front passenger seat is determined based on the propagation time of the maximum amplitude of the reflected signal. 9. The occupant detection method according to claim 8, wherein the occupant is classified.