JP2006243876A - Intrusion alert system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an intrusion alert system, facilitating laying of piezoelectric sensors along a fence or wall or handling thereof without any troubles in appearance or security, and having no fear of reduction in sensitivity or malfunction depending on weather. <P>SOLUTION: The intrusion alert system adapted to detect intrusion of an intruder by detecting application of external force by the intruder to a piezoelectric sensor attached to a boundary of a monitoring section from an output voltage of the piezoelectric sensor comprises piezoelectric cables 10<SB>1</SB>-10<SB>4</SB>laid as piezoelectric sensors over a plurality of sections; a plurality of cascaded detection units 20<SB>1</SB>-20<SB>4</SB>capable of outputting intrusion detection signal based on output voltage after amplification of each piezoelectric cable; and a determination unit 30 performing polling communications with the detection units, and specifying and reporting a detection unit which outputs the intrusion detection signal to an intrusion monitoring device. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an intrusion warning system for detecting an intruder into a monitoring area by a piezoelectric sensor made of a piezo cable and generating an alarm or the like.

  Piezo cables are widely known as so-called piezoelectric sensors, and an insulating layer made of a piezoelectric polymer (piezopolymer) is disposed between a core wire and a mesh-like shielding layer, and the outer side of the shielding layer is an outer sheath such as polyethylene. Protected by a coaxial cable. In this piezo cable, a voltage is generated between the core wire and the shielding layer in accordance with an external force. Therefore, if this voltage is detected, it is possible to detect that some force is applied to the piezo cable.

Paying attention to the function as a piezoelectric sensor of such a piezo cable, for example, a piezo cable is arranged along the end face of a sliding door of a vehicle or an automatic door of a building, and the gap between these door end faces and the opening is provided. An object detection sensor and an open / close body pinching detection device that detect pinching of an object are described in Patent Document 1 described later.
A cord-like pressure sensor input device in which this type of piezo cable is applicable to an input device such as a joystick is described in Patent Document 2 described later.

  On the other hand, a load is applied to an infrared sensor-type monitoring system that detects an infrared beam blocked by an intruder or detects an infrared beam generated from the body and a wire that runs around the monitoring area. Conventionally, a tension sensor type monitoring system that detects and monitors the fact has been known.

Japanese Patent Laying-Open No. 2004-257788 ([0013], [0018] to [0021], FIG. 1, FIG. 2, etc.) JP 2004-205432 A ([0003] to [0010], FIG. 1, FIG. 7 etc.)

In the prior art described in Patent Document 1, the piezo cable is used as a piezoelectric sensor, and at the same time, the shield layer of the piezo cable is also used as a detection electrode of the capacitance sensor, and used as a pair with this detection electrode. Since it is necessary to arrange the cable-like electrode side by side with the piezo cable, the cross-sectional area of the cable-like sensor body tends to be large, in other words, the sensor body tends to be thick.
That is, for example, if the sensor main body is laid for a long distance in order to monitor an intruder into the monitoring area, it may be noticeable because it is conspicuous, and the appearance is not preferable.

  Furthermore, since the prior art described in Patent Document 2 is mainly intended to be applied to an input device, there is a sensor mounting device in which a cord-like pressure sensor is installed upright and a signal line of the pressure sensor is drawn out. It is an indispensable component, and is not suitable for use for laying over a long distance along a fence or the like in order to monitor an intruder or the like.

Infrared sensor type or tension sensor type monitoring systems, which are well known as monitoring systems, generally tend to be expensive, with the former being less sensitive to fog and rain, and the latter being subject to loads due to snow or freezing on the wire. There is a problem of causing malfunction.
For this reason, it has been desired to realize an intrusion warning system that is easy to lay and handle a sensor along a fence or the like, has no aesthetic and security problems, and does not cause a decrease in sensitivity due to weather or a malfunction.
The present invention has been made to solve the above-described problems.

In order to solve the above problem, the invention described in claim 1 is directed to a monitoring area by detecting from the output voltage of the piezoelectric sensor that an external force caused by an intruder is applied to the piezoelectric sensor attached to the boundary of the monitoring area. In an intrusion alert system that detects intruders
A plurality of piezoelectric cables respectively laid over a plurality of sections as the piezoelectric sensor;
Intrusion detection signals can be output by detecting the presence or absence of intrusion from the output voltage amplification value of each piezo cable, and a plurality of detection units connected in cascade,
A determination unit that performs polling communication with these detection units and identifies the detection unit from which the intrusion detection signal is output.

The invention described in claim 2 is the invention according to claim 1,
The detection unit outputs the intrusion detection signal when the output voltage amplification value of the piezo cable continuously exceeds a predetermined detection level for a predetermined time.

The invention described in claim 3 is, in claim 2,
The detection unit further detects the frequency of the output voltage amplification value of the piezo cable and outputs the intrusion detection signal.

The invention described in claim 4 is any one of claims 1 to 3,
The detection unit transmits the intrusion detection signal to the determination unit and returns communication data including at least its own address and intrusion detection data in response to a command from the determination unit.

The invention described in claim 5 is, in claim 4,
The determination unit identifies a detection unit that has transmitted the intrusion detection signal based on the communication data, and transmits communication data including an instruction to cancel the intrusion detection signal to the detection unit.

The invention described in claim 6 is any one of claims 1 to 5,
The detection unit returns communication data including at least its own station address and its own device abnormality data in response to a command from the determination unit.

The invention described in claim 7 is any one of claims 1 to 6,
An AC amplifier is used as an amplifier that amplifies the output voltage of the piezo cable.

According to the present invention, since a piezo cable is used as a piezoelectric sensor, laying and handling along a fence or the like is easy. In addition, since a piezo cable having a simple coaxial structure can be used, there is no fear of deteriorating the appearance or conspicuous in appearance.
Furthermore, an intrusion warning system can be provided that is less susceptible to a decrease in sensitivity or malfunction due to weather compared to a conventional infrared sensor type or tension sensor type monitoring system.
In particular, it is possible to realize an intrusion warning system capable of detecting an intruder with high accuracy by reducing noise and offset components included in the output voltage of the piezo cable.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
First, FIG. 1 is an overall configuration diagram of this embodiment. In FIG. 1, reference numerals 10 ₁ , 10 ₂ , 10 ₃ , and 10 ₄ denote piezoelectric cables as piezoelectric sensors. As is well known, an insulating layer made of a piezoelectric polymer is provided between a core wire and a mesh-like shielding layer. The coaxial cable is formed by arranging and protecting the outer side of the shielding layer with a shell such as polyethylene. Each piezoelectric cable is laid along the fence or the like which is disposed on the boundary of the surveillance zone at a predetermined length, the detection unit 20 1 at both ends of each of the piezo _cable, 20 2, _{20 3,} 20 _4, respectively In addition to being connected, these detection units 20 ₁ , 20 ₂ , 20 ₃ , and 20 ₄ are cascaded. In the illustrated example, four piezo cables and four detection units are provided, but a larger number (for example, up to 32) can be connected in accordance with the size of the monitoring area.

Between each detection unit 20 ₁ , 20 ₂ , 20 ₃ , 20 ₄ and the determination unit 30 described in detail later, address data indicating the address of each detection unit and output voltage level (including peak value) of the piezo cable Intrusion detection data that is output when a voltage exceeding a predetermined detection level (threshold value) continues for a certain period of time is determined to be an intruder, and device abnormality data that indicates an abnormality or disconnection of each detection unit. It can be exchanged as communication data in accordance with a message format to be described later.

The detection unit 20 _first end, the determination unit 30 is connected. When the determination unit 30 receives communication data from the detection units 20 ₁ , 20 ₂ , 20 ₃ , and 20 ₄ side, the determination unit 30 analyzes the data and identifies the detection unit that detected (reported) the intruder. Thus, the address, voltage level, etc. of the detection unit are transmitted to a higher-level intrusion monitoring device (not shown).

Figure 2 is a block diagram showing the internal configuration of the detection unit 20 ₁ and the determination unit 30 ends. Note that these units 20 ₁ , 30 may be integrally formed on a single substrate.
Detection unit 20 ₁ includes an amplifier 201 which analog voltage signals from the piezoelectric cable 10 ₁ (piezoelectric signal) is inputted, a band-pass filter 202 for passing a predetermined frequency component of the output signal, the output signal is input DSP (digital signal processor) 203.
The DSP 203 is provided with A / D conversion means 204 for converting the output signal of the bandpass filter 202 into a digital signal, and peak hold means 205 for holding the peak value of the output signal.
It should be noted that these portions from the amplifier 201 to the peak hold means 205 may be provided with the same configuration as a spare for another channel (two channels) as indicated by a broken line.

Reference numeral 206 denotes detection determination means for determining the output voltage level, duration, frequency, and the like of the amplifier 201. Here, the determination of the frequency may be performed as necessary.
207, detection determination unit 206 of the determination result is digital output means to be added, the detection unit 20 ₁ status display for displaying the abnormality in and detection unit 20 ₁ that has detected the intruder has occurred LED208 And a photocoupler 209 for transmitting to the determination unit 30 an intrusion detection signal that becomes active when the detection determination means 206 detects an intruder intrusion. The intrusion detection signal is transmitted to the determination unit 30 via the signal cable 42.

In addition, a communication processing unit 210, an interface 211, and an RS-485 driver 212 for communicating data with a predetermined communication protocol (RS-485) by a polling method between the determination unit 30 and each detection unit are provided. The driver 212 is connected to the determination unit 30 via the RS-485 communication cable 43.
Further, the DSP 203, and digital input and output unit 213 for generating a digital signal is provided to perform the piezoelectric cable 10 ₁ of disconnection detection, this output means 213, piezoelectric cable 10 a pulse-shaped current signal ₁ is connected to a current detection means (disconnection detection means) 214 for detecting a disconnection by taking in a current signal. The current detection means 214 may also be provided with the same configuration as a spare for another channel (2 channels) as indicated by a broken line.
The result of the disconnection detection is sent to the determination unit 30 through the communication processing unit 210, the interface 211, the RS-485 driver 212, and the communication cable 43 as device abnormality data that is part of the communication data.

The switch for setting the address of the detection unit 20 ₁ 215, 216 flash ROM, 217 of the processing program by the DSP are stored in the SD-RAM, 218 as a work area are connected to the power cable 41 Power switch, 219 is a DC / DC converter for supplying power to the detection unit 20 _1.

  On the other hand, the determination unit 30 includes a photocoupler 301 to which an intrusion detection signal from each detection unit is input, an RS-485 driver 304 connected to the communication cable 43, and a CPU 302 connected thereto. The photocoupler 301 is connected to digital input means 303 in the CPU 302, and the RS-485 driver 304 is connected to an interface 305 in the CPU 302.

  The CPU 302 analyzes the communication data received via the communication cable 43, the driver 304, and the interface 305, identifies the detection unit from which the intrusion detection signal is output, and transmits the information to the intrusion monitoring device. Various commands are transmitted / received to / from, and a digital output means 306 and an interface 307 are provided. The digital output means 306 is connected to contact output means 308 for transmitting information relating to a detection unit in which an intrusion or device abnormality has been identified as a contact output, and an interface 307 is connected via an RS-232C driver 309. Connected to an intrusion monitoring device.

  310 is a detection unit status display LED that collectively displays the status of each detection unit, 311 is an AC / DC converter that converts an external AC power source into a predetermined DC voltage, 312 is a power switch, 313 is a power source for the CPU 302. It is a DC / DC converter for supplying.

Next, FIG. 3 is a conceptual diagram of a waveform obtained by amplifying the output voltage of the piezo cable.
As the voltage level for intrusion detection, the detection determination means 206 is provided with a first detection level and a second detection level. The first detection level is a voltage level at which the detection determination process is started when the voltage level input to the detection determination unit 206 exceeds this level. In other words, the first detection level is the lowest voltage that can be determined to be an intruder by an intruder for the time being. Is a level. In addition, the second detection level is a level that is higher than the first detection level and is a voltage level at which it may be determined that there is an intruder.
The duration for which the input voltage level of the detection determination means 206 exceeds, for example, the first detection level is a parameter that increases the suspicion that there is an intruder as the value increases.

In other words, in general, if the detection level is set high and the duration during which the voltage level exceeds this detection level is increased, a system that reliably detects only intruders by preventing false detection by small animals such as dogs and cats is established. Can be built.
If the frequency during the period when the input voltage level of the detection determination means 206 exceeds the second detection level is added to the determination parameter, for example, it is possible to detect a situation where an intruder has stepped on the piezo cable for a relatively long time. Thus, the detection accuracy can be further increased.
These parameters such as the first detection level, the second detection level, the duration time, and the frequency are appropriately set on the program, and the optimum values are preferably determined by a verification test.

  The peak value of the amplified output voltage of the piezo cable is held by the peak holding means 205 as described above, and is sent to the determination unit 30 as peak data (voltage level data) consisting of 8-bit valid data. This peak data is used to determine the intrusion location by comparing the level difference between adjacent piezo cables (detection units).

Next, FIG. 4 shows a message format of communication data transmitted and received between the determination unit 30 and each detection unit.
First, the simultaneous confirmation command at the time of detection of (1) (its code is [O-00]) detects an intruder by any of the detection units, and the intrusion detection signal is sent to the photocoupler 209, the communication cable 42, the photo This is a command sent from the determination unit 30 to all detection units by simultaneous polling to specify the detection unit when it is input to the CPU 302 via the coupler 301 and the digital input unit 303. Is included.

Next, the detection response of (2) (code is [A-00]) is sent to the determination unit 30 after the detection unit having received the simultaneous confirmation command attaches its own address and a predetermined delay time elapses. It is a reply, its own station address, intrusion detection data (data indicating presence / absence of intrusion), device abnormality data (data indicating presence / absence of abnormality due to disconnection of sensor (piezo cable) or self-diagnosis of detection unit), voltage level Data (the peak data described above) and the like are included.
The individual confirmation command of (3) (code is [O-01]) is to determine the detection unit that has detected the intruder by analyzing the detection response, and then determine the determination unit for the detection unit. This is a command transmitted from 30, and includes a designated address of the detection unit, type data (device operation confirmation, detection confirmation, etc.) and the like.

The device operation confirmation response of (4) (code is [A-01]) is sent sequentially to each detection unit by device operation confirmation polling in order to detect an abnormality of each detection unit. In this case, the response is returned from each detection unit to the determination unit 30 and includes its own address, intrusion detection data, device abnormality data, and the like.
The detection confirmation command response (code [A-02]) in (5) is sent to the determination unit 30 after the detection unit that has received the individual confirmation command in (3) resets the intrusion detection signal of its own station. This is a response to be sent back and includes its own address.

Next, as an example of the operation of this embodiment, FIG. 5 shows a communication procedure when a certain detection unit detects an intruder and outputs an intrusion detection signal.
As described above, when an intrusion detection signal with an intruder is output from a certain detection unit, the determination unit 30 that has received the signal transmits a simultaneous confirmation command [O-00] at the time of detection to all the detection units, Each detection unit returns a detection response [A-00] after the delay time has elapsed. Local address for this detection response [A-00], includes the intrusion detection data or the like, if the detection unit 20 ₂ as shown in FIG. 5 assuming that not output the intrusion detection signal, intrusion detection data " 1 ”, and the voltage level data indicates a peak value.
Therefore, the determination unit 30 can determine the detection unit 20 _2, it is possible to identify the section that detected the intruder other words, notifies the result to the intrusion monitoring device Top.

Determination unit 30, after notifying the intrusion monitoring device, individual confirmation command to immediately detect unit 20 ₂ [O-01] (a type "2": a detection confirmation (request to turn off the intrusion detection signal) ).
Detection unit 20 ₂ receiving the individual confirmation command [O-01], after resetting the intrusion detection signal of its own station, and returns to the determining unit 30 a detection confirmation command response [A-02].
In FIG. 5, T ₀ is a response monitoring timer time. For example, when the response message “STX” is not received within 30 ms, it is determined that a timeout has occurred.

With the above sequence, it is possible to identify the area where the intruder is detected and report the information to the intrusion monitoring device. The intrusion monitoring device can quickly take necessary countermeasures such as alarm output and express to the site. It can be taken.
In addition, when intrusion occurs in a plurality of areas and detection signals are output from a plurality of detection units, the determination unit 30 notifies all of the detection units that have output an intrusion detection signal after notifying the intrusion monitoring device. Then, an individual confirmation command [O-01] (type “2” is set) is sequentially transmitted, and each detection unit returns a detection confirmation command response [A-02] to the determination unit 30, so that all intrusions are made. It is possible to specify the area.

FIG. 6 is a communication procedure for confirming an abnormality of the detection unit, and is a sequence executed at regular intervals.
That is, an individual confirmation command [O-01] (type “1”: device operation confirmation) is sequentially transmitted from the determination unit 30 to each detection unit, and each detection unit sends a device operation confirmation response [A-01]. By replying, the disconnection of the piezo cable and the abnormality of the detection unit due to the self-diagnosis are reported as the own device status. As a result, the determination unit 30 can detect the states of all the detection units, and can quickly take measures such as inspection for the detection units in which an abnormality has been detected.

  In developing this system, the inventor has found that the output voltage of an amplifier that amplifies a piezo signal (corresponding to the amplifier 201 in FIG. 2) is a noise with a very long period compared to a waveform in which a swing or the like is detected In addition, we have obtained the knowledge that it has an offset voltage as the ambient temperature changes. The waveform of channel 1 in FIGS. 7A to 7D shows the output voltage of the amplifier when the temperature is changed from low temperature to high temperature or from high temperature to low temperature in the thermostat (FIG. 7D). 40 ° C. → 41 ° C. → 40 ° C. → 41 ° C. →...

The cause is considered to be the direct current amplifier used as the above-mentioned amplifier, and when this is changed to the alternating current amplifier (the cutoff frequency is set to the frequency of the fence swing by the intruder: about 16 Hz), FIG. The waveform shown in channel 1 in (d) was obtained.
As is clear from these waveforms, it was confirmed that both the noise of the output voltage and the offset voltage were reduced by changing to the AC amplifier. Thereby, it is possible to further improve the detection accuracy of an intruder or the like.

1 is an overall configuration diagram of an embodiment of the present invention. It is a block diagram which shows the internal structure of the detection unit and determination unit of the edge part in FIG. It is a conceptual diagram of the waveform which amplified the output voltage of the piezo cable. It is a figure which shows the message | telegram format of the communication data transmitted / received between a determination unit and each detection unit. It is a sequence which shows a communication procedure when a certain detection unit outputs an intrusion detection signal. It is a sequence which shows the communication procedure for confirming abnormality of a detection unit. It is a wave form diagram of the output voltage of the amplifier which amplifies a piezo signal. It is a wave form diagram of the output voltage of the amplifier which amplifies a piezo signal.

Explanation of symbols

10 ₁ , 10 ₂ , 10 ₃ , 10 ₄ : Piezo cable 20 ₁ , 20 ₂ , 20 ₃ , 20 ₄ : Detection unit 201: Amplifier 202: Band pass filter 203: DSP
204: A / D conversion means 205: Peak hold means 206: Detection determination means 207: Digital output means 208: Status display LED
209: Photocoupler 210: Communication processing means 211: Interface 212: RS-485 driver 213: Digital input / output means 215: Switch 216: Flash ROM
217: SD-RAM
218: Power switch 219: DC / DC converter 30: Determination unit 301: Photocoupler 302: CPU
303: Digital input means 304: RS-485 driver 305: Interface 306: Digital output means 307: Interface 308: Contact output means 309: RS-232C driver 310: Detection unit status display LED
311: AC / DC converter 312: Power switch 313: DC / DC converter

Claims (7)

In an intrusion warning system for detecting an intruder intrusion into the monitoring area by detecting from the output voltage of the piezoelectric sensor that an external force due to the intruder has been applied to the piezoelectric sensor attached to the boundary of the monitoring area,
A plurality of piezoelectric cables respectively laid over a plurality of sections as the piezoelectric sensor;
Intrusion detection signals can be output by detecting the presence or absence of intrusion from the output voltage amplification value of each piezo cable, and a plurality of detection units connected in cascade,
A polling communication is performed for these detection units, and a determination unit for identifying the detection unit from which the intrusion detection signal is output, and
An intrusion warning system characterized by comprising: Intrusion alert system according to claim 1,
The detection unit outputs the intrusion detection signal when the output voltage amplification value of the piezo cable continuously exceeds a predetermined detection level for a certain period of time. Intrusion warning system according to claim 2,
The detection unit further detects the frequency of the output voltage amplification value of the piezo cable and outputs the intrusion detection signal. In the intrusion warning system according to any one of claims 1 to 3,
The detection unit transmits the intrusion detection signal to the determination unit and returns communication data including at least a local address and intrusion detection data in response to a command from the determination unit. Intrusion warning system according to claim 4,
The determination unit specifies the detection unit that has transmitted the intrusion detection signal based on the communication data, and transmits communication data including an instruction to cancel the intrusion detection signal to the detection unit. Vigilance system. In the intrusion warning system according to any one of claims 1 to 5,
An intrusion warning system characterized in that the detection unit returns communication data including at least its own station address and its own device abnormality data in response to a command from the determination unit. In the intrusion warning system according to any one of claims 1 to 6,
An intrusion warning system using an AC amplifier as an amplifier that amplifies the output voltage of a piezo cable.

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