JPH09226521A - Vehicular invasion detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicular invasion detection device which has a function for detecting the existence/absence of the invasion of a person utilized a Doppler shift rightly at a short time without the application of an excessive circuit element and the effect of the swing of an air. SOLUTION: The level of an envelope detection signal is sampled repeatedly at a prescribed sampling timing and found out as sampling values A0 -AM in order and the absolute value |Am-1 -Am | of the difference between mutually continuing respective both sampling values is calculated in order (step 160) during a prescribed time width ΔT in which a present time is a start point. The sum Asum of respective absolute values is calculated and compared and judged with a prescribed threshold value TH which is the judgement standard of the existence/absence of the swing of the air (step 170, 180). When the sum Asum of the absolute value is less than the prescribed threshold value TH, it is judged that the swing of the air exsists and a warning process is prohibited (step 181, 182).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle intrusion detection device, and more particularly to a vehicle suitable for detecting illegal intrusion of a person by utilizing Doppler shift of ultrasonic waves generated when a person intrudes into a vehicle compartment. Intrusion detection device for automobiles.

[0002]

2. Description of the Related Art Conventionally, this type of vehicle intrusion detection device is
A Doppler signal is formed according to the frequency difference between the ultrasonic waves transmitted into the vehicle interior and the ultrasonic waves reflected in the vehicle interior, and it is based on this Doppler signal that the presence or absence of illegal entry of a person into the vehicle interior can be detected. It has become.

[0003]

By the way, in such an intrusion detection apparatus, the use of ultrasonic Doppler shift is inevitably performed using air as a medium. For this reason,
Fluctuations occur in the air in the passenger compartment due to temperature fluctuations in the air, wind blown into the passenger compartment through the windows, and the like. When air fluctuations occur in this manner, the fluctuations affect the Doppler signal, resulting in erroneous detection of a person's invasion into the passenger compartment as an intrusion. For this reason, the user of the vehicle is taking measures such as disabling the intrusion detection device or ignoring an alarm due to an erroneous detection. This means that the original function of the intrusion detection device is lost.

As a countermeasure against such fluctuation of air, as shown in Japanese Patent Laid-Open No. 52-24100,
The Doppler signal is passed through a bandpass filter to extract the frequency component corresponding to the fluctuation of the wind, the frequency component is logarithmically converted and detected, and based on this detection result, false detection due to the fluctuation of the wind is prevented, An intrusion alarm device that attempts to detect an intrusion correctly has been proposed.

However, in the case of this intrusion alarm device, even if the intrusion of a person can be correctly detected, it is necessary to observe the amplitude fluctuation of the frequency component in a long time of seconds for this detection. Further, even if it is possible to detect without requiring such a long time, in the above publication, since the amplitude variation of the frequency component extracted from the Doppler signal is small, simply by the amplitude variation of the frequency component. , It is difficult to correctly identify whether it is due to wind fluctuations or human intrusion. Therefore, there is a problem that an extra circuit for logarithmically converting the frequency component must be additionally adopted.

On the other hand, the inventors of the present invention have conducted an experiment to find out how the envelope level of the amplitude of the received ultrasonic wave differs depending on the fluctuation of air and the intrusion of a person. The characteristics shown in FIGS. 8 and 9 were obtained. In these, the differential value of the envelope level of FIG. 8 with respect to time, that is, the degree of temporal change, and the differential value of the envelope level of FIG. 9 with respect to time, that is,
Comparing the degree of temporal change, it can be seen that there is a clear difference between the two.

Therefore, if the sum of the absolute values of the differential values is calculated within a fixed time, the sum of the absolute values due to the intrusion of a person will be the fluctuation of the air even if this time is short. It is considered that there is a more distinct difference with the sum of absolute values in the case of. Therefore, the present invention pays attention to such a fact, and determines whether or not a person using the Doppler shift has entered, without using extra circuit elements and without being affected by air fluctuations. An object of the present invention is to provide an intrusion detection device for a vehicle that maintains a function of correctly detecting the time.

[0008]

In order to achieve the above object, according to the invention as set forth in claim 1, the calculating means time-wise repeatedly differentiates the detection level of the reception level detecting means to differentiate these differential values. The sum of the absolute values is calculated, and the determination means determines the presence or absence of this fluctuation based on the sum of the absolute values according to the condition representing the fluctuation of the air. Then, based on the determination by the determination means that there is fluctuation, the prohibition means prohibits detection of the presence of a person.

As described above, if the sum of the absolute values of the time-dependent differential values of the detection level of the reception level detecting means is used, the sum of the absolute values may be caused by the fluctuation of air or by the intrusion of a person. Therefore, since a clear difference occurs, it is possible to correctly determine the presence or absence of air fluctuations in accordance with the conditions representing the air fluctuations. As a result, the function that can accurately detect the intrusion of a person into the passenger compartment by using the Doppler shift of ultrasonic waves is maintained without being affected by air fluctuations and without using extra circuit elements. It is possible to provide a vehicle intrusion detection device.

The sum of the absolute values described above is calculated based on the differential value of the detection level of the reception level detecting means. Therefore, even if the calculation time of the sum of absolute values is a short time of less than 1 sec, for example, within a time of about 30 msec to 100 msec, the sum of the absolute values depends on the fluctuation of air and the invasion of a person. There is a clear difference between cases. This means that the intrusion of the person can be detected in a short time.

According to the second aspect of the present invention, the calculating means repeatedly differentiates the detection level detected by the reception level detecting means timewise to calculate the sum of absolute values of the respective differential values, and the judging means. However, it is determined whether or not the sum of the absolute values is equal to or less than the upper limit value that represents the fluctuation of air. Then, based on the determination by the determination means that the value is equal to or less than the upper limit value, the prohibition means prohibits the detection of the presence of a person.

As described above, also by comparing the sum of the absolute values of the respective differential values of the detection level of the reception detecting means with the upper limit value representing the fluctuation of the air, the same operational effect as the invention according to claim 1 can be obtained. Can be achieved.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an example of a vehicle intrusion detection device according to the present invention. This intrusion detection device is provided with an ultrasonic wave transmission / reception sensor S, and this ultrasonic wave transmission / reception sensor S is arranged at the center of the upper edge of the front shield in the vehicle interior of the vehicle, as shown in FIG. ing.

The ultrasonic wave transmission / reception sensor S includes an ultrasonic wave transmitter 10a and an ultrasonic wave receiver 10b. An oscillator circuit 30 is connected to the ultrasonic transmitter 10a via a drive circuit 20, and the oscillator circuit 30 generates an oscillator frequency (4
The oscillation pulse is output at 0 KHz). Drive circuit 20
Drives the ultrasonic transmitter 10a by sequentially receiving oscillation pulses from the oscillation circuit 30. This means that the ultrasonic transmitter 10
a means that ultrasonic waves are transmitted and reflected in the passenger compartment in response to the drive. The ultrasonic transmitter 10a,
The drive circuit 20 and the oscillating circuit 30 form an ultrasonic wave transmission unit of the ultrasonic wave transmission / reception sensor S.

The ultrasonic receiver 10b receives the transmitted ultrasonic waves reflected in the passenger compartment and outputs them to the amplifier circuit 40 as received signals. The amplifier circuit 40 amplifies the reception signal from the ultrasonic receiver 10b and outputs it to the comparison circuit 50 as an amplified voltage having a sine waveform (see FIG. 4). The comparison circuit 50 compares the amplified voltage of the amplification circuit 50 with the reference voltage Vr of the reference power supply 51. Then, the amplified voltage is the reference voltage Vr.
The comparison circuit 50 outputs a comparison signal at a high level only when the comparison signal is higher than the above. The ultrasonic receiver 10b, the amplification circuit 40, the comparison circuit 50, and the reference power supply 51 form a reception unit of the ultrasonic transmission / reception sensor S.

The phase difference output circuit 60 comprises an exclusive OR gate (hereinafter referred to as an EXOR gate 60). The EXOR gate 60 changes the level of both the oscillation pulse of the oscillation circuit 30 and the comparison signal of the comparison circuit 50. According to the above, the phase difference pulse signal is generated by obtaining the difference between the phases of the oscillation pulse and the comparison signal. The bandpass filter 70 (hereinafter, referred to as BPF 70) includes an EXOR gate 6
A frequency component corresponding to the intrusion speed of a person is extracted from the phase difference pulse signal from 0 and a Doppler shift signal is generated.
Here, the frequency difference specified by the Doppler shift signal is a value based on the relative speed of the person with respect to the ultrasonic wave transmission / reception sensor S. The EXOR gate 60 and the BP
F70 corresponds to the Doppler detection unit in the ultrasonic wave transmission / reception sensor S.

The envelope detection circuit 80 has the circuit configuration shown in FIG. 3 and functions as a reception level detecting means. As shown in FIG. 4, the envelope detection circuit 80 has:
The envelope of the amplitude of the amplified voltage from the amplifier circuit 40 is detected and the envelope detection signal is output. Microcomputer 90
According to the flowcharts shown in FIG. 5 and FIG.
Based on each output from the F70 and the envelope detection circuit 80,
A computer program is executed, and during this execution, arithmetic processing required for determining whether or not there is a fluctuation of the wind and illegal entry of a person is performed. The computer program is stored in the ROM of the microcomputer 90 in advance.

The alarm device 100 is a microcomputer 9.
It is controlled by 0 to give an alarm indicating the illegal entry of a person. In the present embodiment configured as above, if the ultrasonic transmitter 10a is driven by the drive circuit 20 based on the oscillation pulse of the oscillation circuit 30 and transmits the ultrasonic waves into the vehicle interior,
This transmitted ultrasonic wave is reflected in the vehicle interior.

Then, the reflected ultrasonic waves are transmitted to the ultrasonic receiver 1.
The received signal is received as a received signal by 0b, and the received signal is output as an amplified voltage by the amplifier circuit 40. Then
The amplified voltage is compared with the reference voltage Vr of the reference power supply 51 by the comparison circuit 50. Here, the amplified voltage is the reference voltage V
When higher than r, the comparison circuit 50 outputs a comparison signal at a high level.

Then, the phase difference output circuit 60 generates a phase difference output signal according to the difference between the phase of the oscillation pulse of the oscillation circuit 30 and the phase of the comparison signal of the comparison circuit 50, and the BPF 70
Outputs a Doppler shift signal based on this phase difference output signal. Further, the envelope detection circuit 80 envelope-detects the amplified voltage of the amplifier circuit 40 and outputs an envelope detection signal.

In such a state, if the microcomputer 90 is operating, the computer program is executed according to the flowcharts of FIGS. 5 and 6. When the computer program reaches step 120, the frequency F of the Doppler shift signal of BPF 70 is calculated. Then, in step 130, it is determined whether or not the frequency F is a value within the predetermined frequency range ΔFo.

Here, the predetermined frequency range ΔFo is a frequency range corresponding to a relative speed of a person invading the passenger compartment with respect to the ultrasonic wave transmitting / receiving sensor S. Then, if the frequency F is a value within the predetermined frequency range ΔFo, the determination in step 130 is YES. Thereafter, at the present stage, if YES in step 140, that is, if the frequency F is not maintained within the predetermined frequency range ΔFo for the predetermined N hours, the determination in step 140 becomes NO, and At 141, the count data D that has been cleared at step 110 is added and updated with D = D + 1.

However, the above-mentioned predetermined N hours corresponds to the time normally required for a person to enter the vehicle interior. If the determination in step 140 is YES due to the lapse of the predetermined N hours, step 1 is determined based on the tentative determination of illegal trespassing by a person.
At 50 (see FIG. 6), the envelope detection signal of the envelope detection circuit 80 is input to the microcomputer 90.

Then, in the next step 160,
A predetermined time width ΔT (for example, 30 ms) from the current time
ec to 100 msec), the level of the envelope detection signal is repeatedly sampled at a predetermined sampling timing and sequentially sampled values A ₀ , A ₂ ,
..., is required as A _M. Here, the suffix M of A _M corresponds to a value obtained by dividing the predetermined time width ΔT by the sampling timing interval P.

Then, the absolute value | A _m-1 -A _m | of the difference between the two consecutive sampling values is sequentially calculated. The absolute value | A _m-1 −A _m | corresponds to the differential value of the level of the envelope detection signal of the envelope detection circuit 80 (see FIGS. 8 and 9). When the processing in step 160 is completed in this way, the next equation 1
The sum Asum of the absolute values is calculated based on the above absolute values according to the above equation.

[0026]

[Equation 1] Then, in step 180, it is determined whether the sum Asum of absolute values is equal to or less than a predetermined threshold value TH.

However, in the present embodiment, the predetermined threshold value T
H is a criterion for determining whether or not the air fluctuates, and it is assumed that the air fluctuates only when the sum Asum of absolute values is equal to or less than a predetermined threshold value TH (see FIG. 7). Where the sum of absolute values A
If sum is equal to or less than the predetermined threshold value TH, the determination in step 180 is YES, and it is determined in step 181 that there is air fluctuation. This means that the determination of YES in step 140 is due to the fluctuation of the air, and the determination of intrusion of a person is incorrect.

Along with this, in the next step 182, alarm prohibition processing is performed. Therefore, as described above, even if it is determined that there is a person intruding due to the Doppler shift, if the air fluctuation causes the alarm 10
False alarms due to 0 are prohibited. On the other hand, if the determination in step 180 is NO, it is determined in step 183 that there is no air fluctuation. This means that the determination of YES in step 140 is not due to the fluctuation of air, and the determination of the intrusion of a person is
Means right.

Along with this, in step 184, alarm processing is performed and the alarm device 100 issues an alarm. As a result, the user of the vehicle can correctly recognize the illegal entry of a person. As described above, in the present embodiment, the absolute value | A _m-1 −A _m | of the difference between the respective sampling values of the levels of the envelope detection signal of the envelope detection circuit 80, that is, the sum of the differential values. Therefore, the sum of the absolute values makes a clear difference between the case of the fluctuation of air and the case of the invasion of a person. Therefore, by comparing the sum of the absolute values with the predetermined threshold value TH, it is possible to correctly determine the presence or absence of air fluctuations.

As a result, it is possible to correctly detect the intrusion of a person into the vehicle compartment using the Doppler shift of ultrasonic waves, without being affected by air fluctuations and without using extra circuit elements. It is possible to provide a vehicle intrusion detection device that maintains the above. Further, the sum of the absolute values described above is calculated based on the differential value of the level of the envelope detection signal of the envelope detection circuit 80. Therefore, it takes a short time to calculate the sum of the absolute values, for example, 30 msec to 100 msec.
Even within a certain period of time, there is a clear difference in the sum of the absolute values depending on the fluctuation of air and the intrusion of a person. This means that the intrusion of the person can be detected in a short time.

In implementing the present invention, as described in the above embodiment, the calculation time of the sum of absolute values is 30 m.
Not limited to sec to 100 msec, for example, 1
Even if the time is less than sec, the same operational effect as that of the above embodiment can be achieved. Further, in implementing the present invention, in the above embodiment, an example of calculating the frequency of the Doppler shift signal and determining whether or not this frequency is within a predetermined frequency range has been described, but instead of this, Doppler Even if it is determined based on the cycle of the shift signal whether or not it is within the predetermined cycle range (corresponding to the predetermined frequency range), it is possible to achieve the same effect as the above-described embodiment.

In the above embodiment, an example in which the ultrasonic wave transmission / reception sensor S is arranged at the center of the upper edge of the front windshield in the passenger compartment has been described.
As shown in (b), the ultrasonic transmission / reception sensor S may be provided on the upper portion of the pillar of the seat belt. Further, in carrying out the present invention, each step in the flowcharts of the above embodiments may be realized by a hard logic configuration as a function executing means.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

2 (a) and 2 (b) are views showing a mounting position of the ultrasonic wave transmission / reception sensor of FIG. 1 on a passenger compartment and an upper portion of a seat belt pillar.

3 is a detailed circuit diagram of the envelope detection circuit of FIG.

FIG. 4 is a timing chart showing input / output waveforms of the envelope detection circuit.

FIG. 5 is a first part of a flowchart showing the operation of the microcomputer of FIG. 1;

FIG. 6 is a latter part of the flowchart.

FIG. 7 is a timing chart showing a relationship with a threshold TH of each sum Asum of absolute values.

FIG. 8 is a graph showing a temporal change of an envelope level when there is fluctuation of air in the vehicle interior.

FIG. 9 is a graph showing a temporal change in envelope level in the case of a person intruding into a vehicle compartment.

[Explanation of symbols]

S ... Ultrasonic wave transmission / reception sensor, 10a ... Ultrasonic wave transmitter, 10b ... Ultrasonic wave receiver, 30 ... Oscillation circuit,
40 ... Amplifier circuit, 50 ... Comparison circuit, 51 ...
Reference power source, 60 ... Phase difference output circuit, 70 ... BP
F, 80 ... Envelope detection circuit, 90 ... Microcomputer.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location G08B 13/00 G08B 13/16 A 13/16 G01S 7/52 J (72) Inventor Hayashi Ikuo Aichi 14 Iwatani, Shimohakaku-cho, Nishio-shi, Japan Inside the Japan Auto Parts Research Institute, Inc. (72) Inventor Takeo Tsuzuki 1-1-1, Showa-cho, Kariya-shi, Aichi Nihon Denso Co., Ltd.

Claims (2)

[Claims] 1. An ultrasonic wave transmitting means (10a, 2) provided in a vehicle compartment of a vehicle for transmitting an ultrasonic wave and reflecting the ultrasonic wave in the vehicle compartment.
0, 30), ultrasonic receiving means (10b, 40, 50, 51) provided in the vehicle compartment for receiving the reflected ultrasonic waves, and based on the Doppler shift amount according to the reflected ultrasonic waves and the received ultrasonic waves. Intrusion detection means for detecting the presence or absence of human intrusion (6
0, 70, 120 to 141), the reception level detecting means (80) for detecting the level of the received ultrasonic wave, and the detection level by the reception level detecting means are repeatedly time-differentiated. Calculating means (160, 170) for calculating the sum of the absolute values of the respective differential values, and a fluctuation determining means for judging the presence or absence of the fluctuation based on the sum of the absolute values according to the condition expressing the fluctuation of the air ( 18
0) and a prohibiting means (182) for prohibiting the detection of the presence of a person based on the determination by the determination means that there is fluctuation, the vehicle intrusion detection device. 2. An ultrasonic wave transmission means (10a, 2a) provided in a vehicle compartment of a vehicle for transmitting ultrasonic waves and reflecting the ultrasonic waves in the vehicle compartment.
0, 30), ultrasonic receiving means (10b, 40, 50, 51) provided in the passenger compartment for receiving the reflected ultrasonic waves, and Doppler shift amounts corresponding to the reflected ultrasonic waves and the received ultrasonic waves. An intrusion detection device comprising intrusion detection means (60, 70, 120 to 141) for detecting the presence or absence of a person based on the reception level detection means (80) for detecting the level of the received ultrasonic wave, and the reception level detection means (80). Calculating means (160, 170) for repeatedly differentiating the detection level by the level detecting means repeatedly to calculate the sum of the absolute values of the respective differential values, and the sum of the absolute values is equal to or less than the upper limit value representing the fluctuation of air. It is characterized by comprising a judging means (180) for judging whether or not there is, and a prohibiting means (182) for prohibiting detection of the presence of a person based on the judgment by the judging means that the value is equal to or less than the upper limit value. Dual-use intrusion detection devices.