KR20100053867A - Wireless acoustic emission sensor - Google Patents

Abstract

PURPOSE: A wireless sound emission sensor is provided to aim the accuracy in a signal transmission by using the RF communication or the local wireless communication. CONSTITUTION: A wireless sound emission sensor(100) comprises a signal detecting unit, a signal processing unit, a communication unit and a power control unit. The signal detecting unit detects the sound emission signal issued from a measuring target. The signal processing unit amplifies and processes the detected sound emission signal. The communication unit changes the sound emission signal into a radio signal and transmits to a remote receiver. IF the sound emission signal is detected, the power control unit supplies the driving power to the signal detecting unit, and the signal processing unit and the communication unit. If not, the power control unit supplies the driving power to the inner control module of the signal processing unit and the signal detecting unit only.

Description

Wireless acoustic emission sensor

The present invention relates to a wireless acoustic emission sensor which detects a small acoustic signal in a single acoustic emission sensor, amplifies and processes the detected acoustic signal, converts the detected acoustic signal into a wireless communication signal, and transmits the wireless acoustic signal to a remote receiving device. will be.

Acoustic emission (AE) refers to the stress wave generated when the strain energy that is locally formed inside the solid is rapidly released, but it is used in a broad sense including not only the physical phenomenon but also the test method using the same. That is, acoustic emission (AE) refers to a technique for detecting and evaluating an acoustic wave (ultrasound region) generated by crack propagation, damage, etc. existing in a material or structure by a non-destructive test method.

Existing AE devices for efficiently capturing and processing such AE signals range from small portables to large equipments of several tens of channels processed by computers, depending on the purpose and the processing and recording method thereof. For example, a piezoelectric (PZT) piezoelectric element (PZT) is used to configure an AE device, and a preamplifier (amplifier) that amplifies the output (fine voltage) of the AE sensor is used as a cable. Was used in connection with AE dedicated equipment, a measuring instrument. The configuration of the existing AE device can be easily installed and used in the test room, but it was inconvenient when it was actually installed and used in the field.

An existing AE device that is easy to apply in the field is an integrated AE sensor that combines an AE sensor and a preamplifier in one sensor module. However, such an integrated AE sensor requires a separate cable to receive power from the outside, and also has a problem in that a cable must be connected to the AE-only device, which is a measurement device.

1 is a view showing the configuration of an embodiment of a conventional sound emitting device.

Referring to FIG. 1, recently, an AE sensor 11, a cable 12, a transmitter 13 in which an amplifier, a signal processing device, and a wireless transmission module are combined, and a receiver 14 installed on the AE dedicated equipment side, which is a measurement device, are provided. A configured sound emitting device is on the market. The conventional sound emitting device does not need to install a separate cable for transmitting and receiving data to and from the AE-only equipment measuring equipment by wireless transmission and reception with the AE-only equipment measuring equipment through a wireless transmission module installed in the transmitter (13), Since the AE sensor 11 and the transmitter 13 are each separate devices, a separate cable 12 is required to connect them.

In particular, the use of cables between the sensor and the transmitter for signal processing and transmission results in constraints that limit the mounting position of the sensor or the object to which the sensor is attached. In other words, when the sensor attachment object is a floating object, it is very difficult to attach the sensor to the floating object due to the use of a cable.

In addition, the conventional acoustic emission device has a disadvantage in that the size of the transmitter, the amplifier, the signal processing device, the wireless communication module, and the power supply device are large, and the convenience of installation and handling is reduced.

On the other hand, another embodiment of the existing sound emitting device is disclosed in Korean Patent Laid-Open Publication No. 10-2004-0093867 (name of the invention: a wireless transceiver for transmitting a sound emission signal). The disclosed technology consists of an acoustic emission sensor (AE sensor), an amplifier, a band pass filter, an RMS converter, a V / F converter, a buffer, a transmitter, a photo transistor, a Schmitt trigger, a logic circuit, a receiver, and an A / D converter.

In another embodiment of the conventional acoustic emission device configured as described above, the acoustic emission sensor detects and amplifies only the AE signal, and has a separate transmission device and a signal processing device, and the acoustic emission sensor and the transmission device have separate cables. This is connected to the signal line and power supply line.

Therefore, another embodiment of the existing acoustic emission device, there is a difficulty in the installation of attaching the acoustic emission sensor to the attachment object, there is a complex that the acoustic emission sensor and the transmission device is implemented separately to design the product separately. In addition, when the power supply unit supplies driving power to the AE sensor or the transmission device, the power is always supplied irrespective of the event, so there is a disadvantage in that waste of power occurs.

In addition, since the optical communication method using the light emitting diode, there is a disadvantage that the accuracy of the signal transmission in the presence of obstacles, and the optical communication method also caused a disadvantage that the restrictions on the installation of the transmitter and the receiver.

Therefore, the present invention has been proposed to solve various problems occurring in the conventional acoustic emission devices as described above.

The problem to be solved by the present invention is to provide a wireless acoustic emission sensor to improve the installation and handling convenience of the sensor by performing the acoustic detection, signal processing, power supply and wireless communication in a single miniaturized acoustic emission sensor. There is.

Another object of the present invention is to provide an ultra-compact wireless acoustic emission sensor capable of supplying self power and having low power consumption.

Another object of the present invention is to provide a wireless acoustic emission sensor for quickly and safely transmitting acoustic emission information.

Another object of the present invention is to provide a wireless acoustic emission sensor capable of relaying a signal transmitted by another acoustic emission sensor.

Another object of the present invention is to provide a wireless acoustic emission sensor that accurately detects acoustic emission and accurately calculates acoustic emission information such as the time and duration of the acoustic emission.

A preferred embodiment of the wireless acoustic emission sensor according to the present invention for achieving the above technical problem,

Signal detecting means for detecting an acoustic emission signal generated from a measurement object, signal processing means for amplifying and processing the detected acoustic emission signal, and converting the processed acoustic emission signal into a radio signal to be transmitted to a remote receiver. Communication means,

The signal detecting means, the signal processing means and the communication means are modularized into a single product.

In addition, the wireless acoustic emission sensor according to the present invention,

The apparatus may further include a power control means for selectively supplying driving power to components configured inside the wireless acoustic emission sensor according to whether the acoustic emission signal is detected.

Preferably another embodiment of the wireless acoustic emission sensor according to the present invention for achieving the above technical problem,

A signal detector for detecting an acoustic emission signal generated from the measurement object;

An amplifier for amplifying the detected acoustic emission signal;

A signal processor for signal-processing and outputting the amplified sound emission signal;

A communication module for converting an acoustic emission signal output from the signal processor into a radio signal and transmitting the radio signal; And

The apparatus includes a power supply for supplying driving power to the signal detector, the amplifier, the signal processor, and the communication module, and minimizing power consumption by selectively performing power control according to whether an event occurs.

In addition, when no event occurs, the power supply is determined to be in a sleep mode and supplies power only to the signal detector and the signal processor. When the event occurs, the power supply is determined to be in a run mode. It supplies a driving power to the module.

Preferably, the communication module further performs a role of relaying the radio signal from the other acoustic emission sensor to the receiver.

More preferably, the signal processor calculates a generation time and a duration of the acoustic emission signal and provides the signal to the communication module, and generates and supplies a power control signal to the power supply.

According to the wireless acoustic emission sensor according to the present invention, since signal detection and processing, power supply, and wireless transmission are possible in a single compact product, it is easy to install or handle on a detection object, thereby improving overall convenience. .

In addition, since it is a miniaturized single product, there is an advantage of minimizing the burden of the detection object even when the product is installed on the detection object.

In addition, it is possible to integrate and manufacture as a single product, which has the advantage of facilitating the production, and depending on whether an event occurs when the built-in battery is used, power is selectively supplied through a power saving mode called sleep mode and run mode. As a result, power consumption can be minimized.

In addition, by using the RF communication method or the short-range wireless communication method for the transmission and reception of the wireless acoustic emission signal, there is an advantage to improve the accuracy in signal transmission.

Hereinafter, described in detail with reference to the accompanying drawings a preferred embodiment of the present invention. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail.

2 is a block diagram showing the configuration of the "wireless acoustic emission sensor 100" according to an embodiment of the present invention, the signal detector 110, the amplifier 120, the signal processor 130, the communication module 140 ) And a power supply 150.

As shown in FIG. 4, the wireless acoustic emission sensor 100 includes the signal detector 110, the amplifier 120, the signal processor 130, the communication module 140, and the power supply 150. It is embedded together as a single product at 160, and in recent years, it is possible to miniaturize the communication module 140, etc., it is possible to miniaturize the product even if the entire product as described above is unified. In particular, in the present invention, for miniaturization of the product, by using an internal battery, but by minimizing the power consumption, it is possible to implement a small configuration of the power supply 150. For example, by controlling the power supply in two operation modes, namely, sleep mode (standby mode) and execution mode (operation mode), depending on whether an event (acoustic emission detection) occurs in the power supply 150, It is possible to minimize the power consumption, a detailed description thereof will be described later.

The signal detector 110 detects an acoustic emission signal generated from the measurement object. Here, acoustic emission is a wave in which elastic energy generated when plastic material is deformed or destroyed in a solid state is transmitted through the solid in the form of sound waves. In order to detect the acoustic emission, a sensor using a piezoelectric element (PZT), which generates charge when an external shock is applied, may be used, and in the case of using such a sensor, the signal detector 110 may smile the detected acoustic emission signal. Output with one charge.

The amplifier 120 amplifies the acoustic emission signal detected by the signal detector 110.

The amplifier 120 is a kind of preamplifier (preamplifier) that amplifies the signal detected by the signal detector 110 before it is processed. The amplifier 120 detects a small charge, which is an acoustic emission signal detected by the signal detector 110, at a predetermined level. Amplify. OP amplifier is usually used as a preamplifier, and it is desirable to maintain the amplification gain range of about 40-60 dB.

The signal processor 130 performs a function of signal-processing the acoustic emission signal amplified by the amplifier 120 and outputting it as an acoustic emission signal, and at the same time, when the acoustic emission signal is detected, a power supply control signal for power control is supplied to the power supply unit ( 150).

As shown in FIG. 3, the signal processor 130 includes a program for operating in a sleep mode and an execution mode, and stores detected acoustic emission data (calculated duration, real time data, and count value detected). When a sound emission signal is detected in association with the memory 132, the real-time clock generator 133 generating a real-time clock (RTC), and the memory 132 and the real-time clock generator 133, the operation mode is set to the sleep mode. Switching to the run mode, converting the detected acoustic emission signal into a square wave, and converting the detected acoustic emission signal into a digital signal to provide to the communication module 140. When the acoustic emission signal is detected, a power control signal corresponding to the execution mode is supplied to the power supply unit. The control unit 131 is provided to the 150.

The real time clock generator 133 provides the real time clock information to the controller 131. The controller 131 calculates real time data by detecting the time of the first count generation time and the time of the last count generation time of the internal counter based on the real time clock information provided by the real time clock generator 133. In addition, the controller 131 may calculate real-time data for each time point at which the counter counts based on real-time clock information.

The memory 132 stores the duration, real time data and the detected count value calculated by the controller 131. The duration, real-time data and the detected count value stored in the memory 132 are stored in association with each other according to the time of occurrence.

Although not shown in the figure, the control unit 131 includes a comparator, a counter, a control module, and the like.

The comparator converts the signal amplified by the amplifier 120 into a square wave and filters the converted signal into a digital signal. In more detail, the comparator samples the signal amplified by the amplifier 120 to a frequency within a predetermined range as needed, and converts the sampled amplitude into a digital signal of a predetermined bit. Here, the predetermined range may be determined according to needs, such as a measurement object and a calculation method. For example, the predetermined range may be sampled at a frequency within a range of 1 MHz to 10 MHz, and a predetermined bit may also be determined as needed, and may be, for example, 12 bits.

The comparator filters and outputs the signal converted into the square wave. That is, only the waveform of the trigger level or higher may be output from the signal converted into the square wave. The trigger level is determined variably, which depends on the acoustic emission emitted by the measurement object.

The counter counts the digital signal converted by the comparator. Here, the counter preferably uses a 12 bit count. The counter counts square waves filtered by the comparator and calculates a count value. For example, the counter may calculate the count value by increasing the count value by one each time the square wave filtered by the comparator is input.

The current value supplied to the signal detector, the amplifier, the comparator and the counter, respectively, is preferably 2 mA or less. In addition, it is preferable that the input current values are the same. As a result, the acoustic emission sensor according to the present invention can detect, amplify, and convert a signal with a small power, thereby reducing the power consumption.

The control module stores the output value of the counter in the memory 132 as an acoustic emission signal, calculates and stores information such as the acoustic emission occurrence time point and the end time data, the acoustic emission duration time, and stores the information in the memory 132. The emission signal (acoustic emission data) is transmitted to the communication module 140 in real time.

The control module has a run mode in which power is supplied and a sleep mode in which power supply is limited, and when the sound emission signal is detected while operating in the sleep mode, which is the initial standby mode, the control module transitions to the run mode. If the acoustic emission signal is not detected for a predetermined time in the execution mode, the state transitions back to the sleep mode.

The control module controls the count of square waves generated by the comparator, calculates a duration from the first count occurrence to the last count occurrence, and detects the count value calculated during the duration. Here, when the count of the counter is stopped for a preset time, the control module ends the count, calculates the duration from the first count occurrence to the last count occurrence, and detects the count value calculated by the counter. If the count is stopped, it means that no square wave is output from the comparator. The preset time is preferably in the range of 1 ms to 5 ms. When the preset time is 5 ms, the control module terminates the count of the counter when the count is interrupted for 5 ms or more. Through this process, the acoustic emission sensor according to the present invention can accurately detect the acoustic emission and accurately calculate the acoustic emission information such as the occurrence time and duration of the acoustic emission.

In addition, when the counter has finished counting, the control module transitions the state from the execution mode to the sleep mode, as is well known. In this case, the power consumption of the power supply 150 is reduced.

In addition, the control module generates a selective power control signal to the power supply 150 according to whether the acoustic emission signal is detected, which will be described in more detail as follows.

The optional power supply control signal includes a power supply control signal in sleep mode that is generated when no sound emission signal is detected and a power control signal in run mode that is generated when an acoustic emission signal is detected. The acoustic emission may be regarded as an event.

The power control signal in the sleep mode is a control signal for limiting the power so that the power supply for maintaining only the minimum operation is performed by the driving power supply of the signal detector 110 and the control unit 131 of the signal processor 130. The power control signal in the mode is a control signal for supplying driving power to all parts requiring power supply in the acoustic emission sensor 100 when the acoustic emission signal is detected.

Therefore, the wireless acoustic emission sensor 100 of the present invention selectively controls the power supply according to whether the acoustic emission signal is detected, thereby minimizing the power consumption when the acoustic emission signal is not detected, thereby minimizing the built-in battery. In the case of using, it is possible to extend the use time, and by extending the use time of the battery, there is an advantage of minimizing the maintenance cost while eliminating the inconvenience of maintenance due to frequent battery replacement.

The communication module 140 converts the sound emission signal (sound emission data) output from the signal processor 130 into a wireless signal and transmits the converted signal.

That is, the communication module 140 converts the duration calculated by the signal processor 130 and the detected count value into a wireless signal, and transmits the result to a receiving device located remotely. In addition, the communication module 140 transmits the real time data calculated by the signal processor 130. For example, the duration, count value and real-time data can be transmitted wirelessly to the AE dedicated device, which is a measurement device.

Preferably, the communication module 140 may use Zigbee communication, Bluetooth communication, or the like, which is short-range wireless communication. Alternatively, the communication module 140 may also use RF communication.

Zigbee is a standard that is being used to use the IEEE 802.15.4 standard for various industrial applications. It is a technology for short-range communication of about 10 to 100 m and recently ubiquitous computing in wireless networking such as home / office. Zigbee is a very small size, low power, low cost wireless communication protocol that requires simple functions unlike 802.11 or 802.15 in wireless communication. Accordingly, the wireless acoustic emission sensor of the present invention can wirelessly quickly and safely transmit the acoustic emission signal, minimize the power consumption for transmission, and do not need to install and connect a separate communication equipment for wireless communication. It is easy to manage.

Meanwhile, the communication module 140 may also relay a signal transmitted from another acoustic emission sensor to the AE-only device. That is, the communication module 140 of the wireless acoustic emission sensor according to the present invention receives the acoustic emission information transmitted by the other acoustic emission sensor, and transmits it to another acoustic emission sensor or AE-only equipment. If a unique number (ID) is added to each of the acoustic emission information, the AE base station can determine whether the acoustic emission information easily received is a detection signal of the acoustic emission sensor installed in the location. Will be. In this manner, even when the AE base station is installed at a distance of 1 km or more, it is possible to accurately transmit acoustic emission information wirelessly.

The power supply 150 serves to supply driving power to the signal detector 110, the amplifier 120, the signal processor 130, and the communication module 140, and whether or not an event (sound emission) occurs. Accordingly, power control is selectively performed to minimize power consumption.

For example, the power supply 150 preferably uses a lithium ion battery as an internal battery. Since the power supply 150 embedded in the acoustic emission sensor 100 is modularized into a single product with the signal detector 110, the amplifier 120, the signal processor 130, and the communication module 140, the integrated production is possible. When supplying power to the part requiring power, no separate power supply cable is needed. For this reason, it is possible to produce a very small acoustic emission sensor 100.

As is well known, the wireless acoustic emission sensor according to the present invention can be manufactured in a small size by embedding both a sensing function, an amplification function, a signal processing function, a communication function, and a power supply function in one case 160, There is an effect that can easily install the acoustic emission sensor, there is an advantage that no separate power supply or separate cable for data transmission and reception. In conclusion, the non-use of such a cable will improve the convenience of handling and installing the acoustic emission sensor.

Although the preferred embodiments of the present invention have been shown and described above, the present invention is not limited to the above-described specific preferred embodiments, and the present invention belongs to the present invention without departing from the gist of the present invention as claimed in the claims. Various modifications can be made by those skilled in the art, and such changes are within the scope of the claims.

The wireless acoustic emission sensor according to the present invention detects acoustic signals emitted by deformation, cracks, etc. of materials or structures, and can predict physical phenomena that proceed in the interior. It is possible to be used in the field.

1 is a schematic configuration diagram of an embodiment of a conventional sound emitting device.

Figure 2 is a block diagram showing the configuration of a preferred embodiment of a wireless acoustic emission sensor according to the present invention.

3 is a block diagram illustrating an exemplary configuration of the signal processor of FIG. 2.

Figure 4 is a perspective view showing the configuration of a wireless acoustic emission sensor according to the present invention.

<Explanation of symbols for the main parts of the drawings>

100... Acoustic Emission Sensor

110... Signal detector

120... amplifier

130... Signal processor

140... Communication module

150... Power supply

Claims (8)

In the sensor for detecting the acoustic emission signal generated from the measurement object, Signal detection means for detecting an acoustic emission signal generated in the measurement object, signal processing means for amplifying and processing the detected acoustic emission signal, and converting the processed acoustic emission signal into a wireless signal and transmitting it to a remote receiver Including communication means, And said signal detecting means, signal processing means and communication means are modularized into a single product. The wireless acoustic emission sensor according to claim 1, further comprising power control means for selectively supplying driving power to a component configured inside the wireless acoustic emission sensor according to whether the acoustic emission signal is detected. According to claim 2, wherein the power control means, When the sound emission signal is detected, the driving power is supplied to the signal detection means, the signal processing means, and the communication means, and when the sound emission signal is not detected, only the internal control module of the signal detection means and the signal processing means. Supplying a driving power, the wireless acoustic emission sensor, characterized in that to minimize the power consumption when the acoustic emission signal is not detected. In the wireless acoustic emission sensor for detecting the acoustic emission signal generated from the measurement object, A signal detector for detecting an acoustic emission signal generated by the measurement object; An amplifier for amplifying the detected acoustic emission signal; A signal processor for signal-processing and outputting the amplified sound emission signal; A communication module for converting an acoustic emission signal output from the signal processor into a radio signal and transmitting the signal to a receiver; And And a power supply for supplying driving power to the signal detector, the amplifier, the signal processor, and the communication module, and minimizing power consumption by selectively controlling power according to whether an event occurs. The method of claim 4, wherein the power supply is determined to be in a sleep mode when no event occurs, and supplies driving power only to the signal detector and the signal processor. Wireless acoustic emission sensor, characterized in that for supplying driving power to the amplifier, signal processor and communication module. The wireless acoustic emission sensor of claim 4, wherein the communication module further performs a function of relaying the wireless signal to the receiver when a wireless signal is transmitted from another acoustic emission sensor. The wireless acoustic emission sensor according to claim 4, wherein the signal processor calculates a generation time and a duration of the acoustic emission signal and provides the calculated signal to the communication module. The power supply control signal of claim 7, wherein the power control signal supplies a sleep mode power control signal for supplying driving power only to the signal detector and the signal processor, and power supply for driving the signal detector, the amplifier, the signal processor, and the communication module. Wireless acoustic emission sensor comprising a run mode power control signal.

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