JP7264565B2 - Crack sensor and low-power driven crack detection system using the same - Google Patents

Description

TECHNICAL FIELD The present invention relates to a crack sensor, and more particularly, to a crack sensor having a greatly improved structure and manufacturing process, and using the crack sensor to obtain set crack data and transmit it in an ultra-low power driving method, which is easy to install. and relates to a low power driven crack sensing system applicable to a wide variety of structural crack morphologies.

Since the 1970s, the rapid economic development of our country has led to the early establishment of domestic industrial technology bases, and the investment of various social indirect capitals for the improvement of the living environment has increased. New construction was also actively carried out.

However, problems due to such rapid growth have appeared in recent years after more than ten years. The most prominent of these accidents are the collapse of buildings, including the collapse of Shinhaengju Bridge (July 1992), the collapse of Uam shopping district in Jeonju (January 1993), and the collapse of Seongsu Bridge (October 1994). ), the Sampung department store (June 1995), and the Gyeongju Mauna Resort (February 2014).

The collapse of such structures not only leads to economic loss, but also leads to large-scale damage to human life, and not only direct and indirect losses such as social unrest and shock, but also lowers national credibility and hinders the economy. act as a factor.

Therefore, in 1995, the ``Special Act on Safety Management of Facilities'' was enacted, and major facilities such as long bridges are required to install and operate sensor-based measurement systems. Doosan We've The Zenith and Lotte Tower No. 2 are equipped with wind direction and speed sensors, vibration acceleration sensors, etc. to carry out building maintenance and safety management.

However, many existing buildings that are used in a dilapidated state are still often not managed in this way. Evaluation is impossible, and a building monitoring and soundness evaluation system is needed to obtain a computer model that reflects the dynamic behavior of the actual structure.

Therefore, various types of crack sensors, such as distance measurement sensors and Hall effect sensors, have been developed to monitor buildings. This results in high manufacturing costs and high power consumption by periodically performing sampling data measurements to obtain sensed crack information and wireless transmission of the sampled data, thus reducing battery life. It shortens and has problems due to power supply disruptions.

Therefore, it is necessary to develop wireless-based measurement equipment and systems that can solve the wired method, which requires high construction costs, including existing expensive sensors, especially in high-rise buildings that occupy a large area. There is an increasing demand for crack sensing systems that provide continuous and smooth monitoring at reasonable cost.

Korean Patent Publication No. 10-2006-0033564

The present invention was created to solve the above-mentioned problems, and an object of the present invention is to have a simple structure, easy manufacturing and installation, cost reduction effect, and excellent reliability. To provide a crack sensor.

Another object of the present invention is to omit zero point adjustment work after installation based on the above crack sensor, minimize power consumption due to wireless transmission of detected crack information, and improve safety management of facilities. It is an object of the present invention to provide a crack sensor capable of improving performance and efficiency and a low-power driven crack detection system using the same.

In order to achieve the above objects, the crack sensor of the present invention is a crack sensor installed in a crack portion of a building to detect a crack state, wherein one side of the crack portion has a longitudinal direction corresponding to the crack direction. a first substrate made of a non-conductive material with a lower surface attached to the building and an upper surface attached with the first electrode portion; and a longitudinal direction corresponding to the crack direction on the other side of the crack portion. a second substrate made of a non-conductive material having a lower surface attached to a building and an upper surface attached to a second electrode; a resistor pattern unit that is bonded to the body, is not stretched, and is broken by a set tensile force, has a length that sequentially changes, and is configured in a bent form so as to be separated from the crack. characterized by comprising

Here, the width or thickness of the resistor pattern part varies depending on the length of each resistor pattern body, and the resistance of all the provided resistor pattern bodies can be configured to be the same.

Also, the resistor pattern unit may include two or more resistor pattern bodies having the same length.

In order to achieve the above objects, the crack detection system of the present invention comprises the above-mentioned crack sensor, a power supply section for applying DC power through an anode and a cathode, and a DC power supply with a set period and pulse. A driving unit that applies voltage to the first electrode unit and the second electrode unit, a measuring unit that is connected to the driving unit and measures the current flowing through the crack sensor, and a crack information that monitors the measured current and changes the current value. and a communication unit that performs wireless communication with a designated server or terminal and is activated by sensing a change in current value by the calculation unit to transmit crack information. Characterized by

Here, the control unit includes a storage unit in which crack values corresponding to changes in current values flowing through the crack sensors are stored in the form of a lookup table, and the calculation unit stores changes in the measured current values. Crack information can be generated by comparison with part information.

The present invention detects cracks generated in various buildings by discrete changes in electrical resistance and transmits the detected changes to a server or a terminal, thereby enabling real-time confirmation and response to the current progress of cracks.

In particular, by using a non-conductive substrate with little flexibility or malleability and a conductive material such as solder cream, it is possible to obtain advantages in terms of process and cost, and any form of structure with a simple structure. It is very easy to put on and take off. Here, by using recycled resources such as waste paper as the material of the substrate, it is economically efficient.

Also, ultra-low power operation is possible because communication occurs only when crack events are sensed by sequential and discrete resistive ruptures.

FIG. 4 is a plan view showing a mask for manufacturing crack sensors according to the present invention; 1 is a plan view of a crack sensor in which electrode parts are aligned according to the present invention; FIG. FIG. 2 is a front view of a crack sensor with electrodes aligned according to the present invention; FIG. 4 is a circuit diagram showing parallel-connected resistors in accordance with the principles of the present invention; 1 is a block diagram showing the configuration and connection relationship of a crack sensing system according to the present invention; FIG. 4 is a flow chart illustrating a crack sensing procedure according to the invention; FIG. 4 is a plan view showing a mask for manufacturing crack sensors according to another embodiment of the present invention; FIG. 4 is a usage state diagram showing the installation state of the bending surface of the crack sensor of the present invention.

Hereinafter, the structure and configuration of the crack sensor and the low-power driven crack detection system using the crack sensor of the present invention will be described in detail with reference to the accompanying drawings.

First, the crack sensor 1 according to the present invention is a sensor installed in cracks generated in various buildings to detect progress of the cracks, and the first substrate 11 is placed on one side of the cracks centering on the cracks. , and a second substrate 12 is attached to the other side of the crack.

Both the first substrate 11 and the second substrate 12 are made of a non-conductive material, and the lower surfaces thereof are attached to the surface of the building through various adhesive means. A resistor pattern portion 13 is provided between the two substrates 12, and DC power is periodically applied to these to monitor the current, and the progression of the crack is determined based on the change in the current value.

For this purpose, a first electrode portion 111 and a second electrode portion 121 are provided on the first substrate 11 and the second substrate 12, respectively, and one end and the other end of the resistor pattern portion 13 are respectively connected to the first electrode portion 111. And, the plurality of resistor pattern bodies 131 which are bonded to the second electrode part 121 and are not stretched and are broken by a set tensile force are configured in a form in which the lengths are sequentially changed, and the crack progresses and the crack spreads. Therefore, the shortest resistor pattern body 131 is sequentially and discretely cut.

One of the major characteristics of the crack sensor 1 according to the present invention is that the manufacturing process is very simple and the cost can be greatly reduced. There are advantages.

FIG. 1 is a plan view showing a mask for manufacturing crack sensors according to the invention. A detailed structure of such a crack sensor will be described along with a manufacturing process as follows.

First, the first substrate 11 and the second substrate 12 can be made of various non-conductive plate materials. In the embodiment of the present invention, the first substrate 11 and the second substrate 12 are made of paper materials such as waste paper, thereby maximizing process easiness and cost reduction. The first substrate 11 and the second substrate 12 can be constructed from a variety of non-conductive materials, such as paper, which have very low flexibility and malleability, even if they are not the materials mentioned.

Also, although it is preferable to simultaneously manufacture the first substrate 11 and the second substrate 12 from the same material as in the embodiment of the present invention, it goes without saying that they can be constructed from other materials having the same characteristics. stomach.

After preparing the frame of the first substrate 11 and the second substrate 12 so as to have an appropriate length corresponding to the position and size of the crack portion to be applied from the material having the characteristics described above, the first electrode portion is placed on the upper side thereof. 111 and the base of the second electrode part 121 are provided.

In an embodiment of the present invention, a thin metal mask having a thickness of 0.05 to 0.5 mm is placed on the material for forming the first substrate 11 and the second substrate 12, and the first electrode portion 111 and the second electrode portion are formed. 121 foundations are provided. Here, the portion to be the first electrode portion 111 is composed of a single metal mask having a predetermined length, and the portion corresponding to the second electrode portion 121 is provided in the number corresponding to the number of the resistor pattern bodies 131. , are arranged at predetermined intervals so as to become progressively farther or closer to the metal mask that becomes the first electrode portion 111 .

Substantially, the metal mask on the side of the first substrate 11 can be used immediately as the first electrode portion 111, but the plurality of metal masks provided on the side of the second substrate 12 will eventually be attached to a single conductor in a straight line. can be separated by the contact portion 132.

After that, the resistor pattern body 131 is formed. Here, preferably, a solder cream (or a cream-type conductive material) is applied to the metal mask corresponding to the first electrode part 111 and the metal mask corresponding to the contact part 132 so as to be connected to each other. A predetermined number of them are provided in parallel. Here, as the distances from the metal masks corresponding to the first electrode portions 111 of the plurality of metal masks forming the contact portions 132 are changed, the solder cream is also applied to a plurality of different lengths.

After that, it is baked in an oven or the like at a temperature of about 240° C. for about 5 seconds to form a solder cream pattern, that is, a resistor pattern portion 13 as shown in FIG. Such conditions are only an example, and it is clear that depending on the applied conductive material, the molding conditions are about 180-280° C., and the molding time can be adjusted appropriately.

As another example, the gravure printing method can be used as another method of forming the resistor pattern portion 13 with solder cream, and the solder cream pattern can be formed by directly injecting the solder cream onto the substrate material by an inkjet method. can also

In addition, after forming a transparent conductive oxide-based thin film such as Indium Tin Oxide (ITO) or Fluorine-doped Tin Oxide (FTO), the resistor pattern portion 13 is formed using a dedicated patterning process. can also be formed.

Through this process, the resistor pattern body 131 formed as shown in FIG. 1, the first electrode part 111 and the contact part 132 are separated by using a knife or a press with a blade.

FIG. 2 is a plan view of a crack sensor having electrodes aligned according to the present invention. After the above-described process, a conductor plate such as copper (or various commercial metal conductors) is aligned with a metal mask forming a contact portion 132 as shown in FIG. It is attached to the two-electrode part 121 .

It goes without saying that such a manufacturing process is only a conceptual part, and that there are various methods for manufacturing the crack sensor 1 substantially as shown in the accompanying drawings.

FIG. 3 is a front view of a crack sensor in which electrode parts are aligned according to the present invention. The state which looked at the formed product from the front is shown. The second electrode part 121 may be formed using various copper tapes or conductive materials.

After that, in order to prevent the corrosion of the materials used, a waterproof treatment is applied using a waterproof paint or the like to ensure smooth use outdoors and improve durability.

As a method different from the one mentioned above, the resistor pattern portion 13 can be made of a conductor line of a conductive material which can be bent without being stretched but which can be easily cut. For example, after forming a transparent conductive oxide (Transparent Conductive Oxide) thin film such as ITO (Indium Tin Oxide) or FTO (Fluorine-doped Tin Oxide), each resistor pattern body 131 can be formed by a patterning process. .

Due to such a simple structure, the present invention is not only easy to manufacture and inexpensive to manufacture, but also easy to install and does not necessarily require zero point adjustment after installation unlike existing products. In the present invention, the time point at which the shortest resistor pattern body among the many resistor pattern bodies 131 forming the resistor pattern portion 13 is cut is called the zero point adjustment.

FIG. 4 is a circuit diagram showing parallel-connected resistors according to the principles of the present invention.

According to Ohm's law V=IR, the total resistance R in a circuit diagram such as that of FIG. 4 can be expressed as (1/(1/R1+1/R2+1/R3 .

Therefore, when one of the shortest resistor patterns is broken, the total resistance value increases, and when the second and shortest resistor pattern is broken, the total resistance value is further increased, resulting in sequential and discrete resistance. A change in value causes a change in current value, and the current displacement (crack progress) is known by a current vs. crack value lookup table constructed by measuring the reference current value.

FIG. 5 is a block diagram showing the configuration and connection relationship of the crack sensing system according to the present invention, and FIG. 6 is a flow chart showing the crack sensing procedure according to the present invention. By integrating the above-mentioned crack sensor 1 with IoT technology and minimizing power consumption during wireless transmission of crack sampling and sensed crack information, a system suitable as an IoT crack sensor whose battery life is important is constructed. can do. In addition, since the measured crack information is transmitted to the server and can be checked by the manager, the current crack status is received in real time to support quick response.

Specifically, the system according to the present invention includes a power supply unit 2, a control unit 3, and a communication unit 4 in addition to the crack sensor 1 described above.

The power supply unit 2 is composed of various batteries, and is configured to apply DC power from the anode and the cathode to the first electrode unit 111 and the second electrode unit 121 of the crack sensor through the control unit 3. .

A suitable commercial battery can be used depending on the size and service life of the crack sensor 1 . As described above, by transmitting information only when a crack event occurs with respect to sequential and discrete crack sensing information, ultra-low power operation is possible, and one AA type dry battery is sufficient. It can be used without battery replacement for a long period of 3 years or more.

Here, the battery power supply can be used as it is, but the battery output voltage is stepped up or down to an appropriate level (3.3V/2.5V/1.8V/1.3V/0.8V, etc.), Allow the battery to act as a constant voltage source.

The power supply unit 2 includes a control unit 21 formed of a voltage control circuit for voltage control and a conversion unit 22 formed of a constant voltage regulator for constant voltage operation.

The control unit 3 has a configuration corresponding to an MCU, and includes detailed configurations of a driving unit 31 , a measuring unit 32 , a storage unit 33 , a calculating unit 34 and a setting unit 35 .

The drive unit 31 is configured to apply the DC power of the power supply unit to the first electrode unit and the second electrode unit with a predetermined cycle and pulse. This can also be implemented from a pulse generator using a DC-AC converter, preferably performing the function of single pulse generation in the MCU dimension for efficient power saving.

A measurement period of several to several hundred milliseconds (ms) can be applied depending on the purpose and application of the measurement, and generally several seconds to several minutes can be applied. The appropriate measurement pulse width is about 1/100,000,000 to 1/100 of the measurement period, but it goes without saying that it can be adjusted depending on the purpose and application of the measurement.

The measuring unit 32 is connected to the driving unit 31 and constitutes a current sensor that measures the current flowing through the crack sensor. The calculating unit 34 monitors the measured current and generates crack information according to changes in the current value. do.

For this purpose, it is necessary to first measure the reference current value flowing through the crack sensor 1 at a predetermined measurement period and pulse width, and create a lookup table showing the current value versus the crack value. The lookup table can be obtained by calculation from the numerical values of the resistor pattern portion 13 on the drawing and the resistivity of the material constituting it, that is, the solder cream in the embodiment of the present invention. Since the theoretical value and the actually measured value may differ due to deviations in the process of forming the pattern body 131, it is preferable to measure the reference current value and create a lookup table.

The storage unit 33 is configured to store crack values corresponding to changes in the current value flowing through the crack sensor in the form of a lookup table. It is configured so that it can be set together and a constant voltage level can be set.

The communication unit 4, which is an IoT-based wireless communication module, performs wireless communication with a designated server or terminal, and is activated by detecting a change in current value by the calculator to transmit crack information.

That is, the current value measured by the crack sensor 1 according to the set constant voltage level, measurement period and pulse width is compared with the current value measured immediately before and stored in the storage unit. The communication unit 4 is activated to transmit the crack information only when the unit 4 remains inactive and does not transmit the calculated crack information, and there is fluctuation.

Due to this operation, the communication unit is activated and operates only n times, which is equal to the number (n) of the designed resistance patterns R1 to Rn, to transmit the crack information, thereby reducing the power consumption of the crack sensor and the entire system. can be minimized.

In addition, in the present invention, in order to create a lookup table intuitively and easily, the width or thickness of the resistor pattern portion 13 varies according to the length of each resistor pattern body, and all the provided resistors are provided. The resistance of the pattern bodies can be configured to be the same.

That is, in the parallel circuit diagram as shown in FIG. 4, it is assumed that the resistors R1 to Rn are all designed to have the same resistance value, and the thicknesses of the resistors R1 to Rn are the same for the sake of manufacturing convenience.

For example, if the length of R1 is L1 and the width is W1, the length of R2 is L2 and the width is W2, and the number of squares is the same, the values of both resistors will be the same.

That is, the value of W2 that satisfies L1/W1=L2/W2 is W2=W1×L2/L1.

If W2 is designed to be larger than W1 by L2/L1, R1=R2 is satisfied, and if the line widths of R3 to Rn are set in this way, all resistance values will be the same.

FIG. 7 is a plan view showing a mask for manufacturing a crack sensor according to another embodiment of the present invention, showing a state in which two or more resistor pattern bodies having the same length are provided in the resistor pattern portion 13. FIG. .

That is, by providing another resistor pattern set (R1' to Rn') similar to R1 to Rn as shown in FIG. , can be replaced with a resistor pattern body having the same length, and furthermore, for cutting of one resistor pattern body, it is possible to double check whether the cutting is due to a normal increase in crack size. Therefore, more accurate crack determination can be performed.

FIG. 8 is a usage state diagram showing a bending surface installation state of the crack sensor of the present invention.

The crack detection system of the present invention can measure the total amount of cracks generated along a curved surface such as a cylinder as shown in FIG. It shows much better performance than other types of crack sensors.

The rights of the present invention are not limited to the embodiments described above, but are defined by what is described in the claims, and any person skilled in the art in the field of the invention may make various modifications within the scope of the claims. And it goes without saying that adaptations are possible.

Reference Signs List 1 crack sensor 11 first substrate 111 first electrode portion 12 second substrate 121 second electrode portion 13 resistance pattern portion 131 resistance pattern body 132 contact portion 2 power supply portion 21 adjustment portion 22 conversion portion 3 control portion 31 drive portion 32 measurement portion 33 storage unit 34 calculation unit 35 setting unit 4 communication unit

Claims (5)

A crack sensor installed in a cracked part of a building and detecting a crack state,
A first substrate (11) made of a non-conductive material having a longitudinal direction corresponding to the direction of the crack on one side of the crack, a lower surface attached to the building, and a first electrode unit (111) attached to the upper surface. )and,
A second substrate (12) made of a non-conductive material having a longitudinal direction corresponding to the direction of the crack on the other side of the crack, a lower surface attached to the building, and a second electrode portion (121) attached to the upper surface. )and,
A plurality of resistor pattern bodies (131) whose one side end and the other side end are joined to the first electrode part (111) and the second electrode part (121), respectively, and which are broken by a set tensile force without being stretched are sequentially formed. and a resistive pattern portion (13) having varying lengths and configured in a bent configuration away from said crack portion. The resistance pattern part (13) has a width or thickness that varies according to the length of each resistance pattern body (131), and the resistance of all the provided resistance pattern bodies is the same. Item 1. The crack sensor according to item 1. The crack sensor according to claim 1, characterized in that the resistor pattern part (13) comprises two or more resistor pattern bodies having the same length. a crack sensor (1) according to any one of claims 1 to 3;
a power supply unit (2) for applying a DC power supply through an anode and a cathode;
A driving part (31) for applying the DC power to the first electrode part (111) and the second electrode part (121) with a set period and pulse, connected to the driving part (31) through a crack sensor. a control unit (3) comprising a measuring unit (32) for measuring the flowing current and a calculating unit (34) for monitoring the measured current and generating crack information according to changes in the current value;
a communication unit (4) that performs wireless communication with a designated server or terminal, and that is activated by detecting a change in current value by the calculation unit and transmits crack information. . The control unit (3) includes a storage unit (33) in which crack values corresponding to changes in current values flowing through the crack sensor (1) are stored in the form of a lookup table,
5. The crack detection system according to claim 4, wherein the calculator (34) compares the measured current value change with the information of the storage unit (33) to generate crack information.

Images