JPH1183420A - Strain measuring module and multipoint-strain measuring system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform a precise strain-measurement stably, by connecting a module main body modulalizing processing circuits of measured signals corresponding to strain amounts of strain gauges, near an object, to which the strain gauges are stuck. SOLUTION: Plural strain gauges 1 are stuck respectively, to, each part of an object, and a module main body 2 is connected with the strain gauges 1 on each measuring point respectively, to thereby compose strain measuring modules 3. A measured-data processing device 4 collects and processes the measured data obtained from each strainmeasuring module 3. Each strain measuring-module 3 is composed of required circuits integrated as a small module by using a single-tipped personal computer or the like, and the module body 2 is connected nearby with the strain gauges 1. Pairs of the strain gauges 1 on each measuring point and the measuring modules 3 are classified into plural groups G, and connected respectively with each sub-communication line 5, and united into a common main communication line 6, and successively connected with the measured-data processing device 4. Therefore, the bad influence on the precision of the measurement or the stability caused by connecting lines can be avoided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a strain measuring module for measuring strain of various objects and a multi-point strain measuring system for measuring the strain at multiple points.

[0002]

2. Description of the Related Art In the fields of machinery, civil engineering, construction, and the like, when measuring the amount of strain of an object such as a machine or a structure, measurement is generally performed using a strain gauge. In strain measurement of an object such as a machine or a structure, multipoint measurement for measuring strain at a plurality of portions of the object is generally performed. In the specification of the present application, unless otherwise specified, in addition to the strain in the ordinary sense, "strain" including the stress of the object
The distortion in the usual sense is, in principle, the reference
(Including subscripts).

[0003] This type of strain measurement is usually performed using a Wheatstone bridge circuit as shown in FIG.
That is, FIG. 7 shows a conventional basic measuring system based on, for example, the 1-gauge method, in which a strain gauge a is attached to a measuring site of an object (not shown) and connection lines c1 and c2 are provided.
Is connected to the strain measuring device A via In this case, the resistances b1 and b2 having fixed resistance values
, B3 are provided, and a strain gauge a is connected to the other side of the Wheatstone bridge circuit h. At the time of strain measurement, an input voltage V (constant voltage) is applied between a pair of diagonal points of the Wheatstone bridge circuit h from the bridge power supply circuit d provided in the strain meter A, and the remaining pair of diagonal points is used. In the meantime, an output voltage Δe as a measurement signal corresponding to the distortion amount of the object is generated. At this time, if the resistance values r1 and r2 of the connection lines c1 and c2 are sufficiently small, the output voltage Δ
e is expressed by the following equation (1) using the resistance value Ra, R1, R2, R3 of the strain gauge a and the resistances b1, b2, b3 and the input voltage V.

Δe = [(RaR 2 −R 1 R 3) / (Ra + R 1) (R 2 + R 3)] V (1) In this case, when the resistance value of the strain gauge a in a normal state is R, R 1 = R 2 = R 3 = R, where ΔR (Ra = R + ΔR), where ΔR (Ra = R + ΔR) is the amount of change in the resistance value of the strain gauge a due to the distortion of the object. 1) can be rewritten as the following equation (2).

Δe = (ΔR / 4R) V (2) Further, the resistance value R of the strain gauge a and its change ΔR
And the strain amount ε (here, the strain amount in the normal direction in the tensile or compressive direction) of the measurement site of the object to which the strain gauge a is attached, the following relational expression (3) holds. Ε = (ΔR / R) / K (3) where K is the gauge factor of the strain gauge a. From the relational expression (3) and the expression (2), the following expression (4) or (4) ′ Is obtained.

Δe = (V / 4) Kε (4) ε = (4 / VK) Δe (4) ′ Therefore, the output voltage Δe of the Wheatstone bridge circuit h
Is proportional to the amount of strain ε at the measurement site of the object to which the strain gauge a is attached, and the output voltage Δe
As a result, the strain amount ε can be measured. When the stress of the object is represented by σ, a proportional relationship of the following formula (5) is generally established between the stress and the strain ε. Therefore, σ = Eε (5) where E is the Young's modulus of the object. The stress can also be measured by the voltage Δe. This is the basic method of strain measurement.

[0007] In addition to the measurement method described above,
A two-gauge method in which four strain gauges are attached to a measurement site of an object or a four-gauge method in which four strain gauges are attached to a measurement site of an object
There are methods such as the gauge method, but in either method,
Basically, a Wheatstone bridge circuit including a strain gauge attached to an object generates a measurement signal proportional to the amount of strain of the object.

In the above-described multipoint measurement, for example, a measurement system as shown in FIG. 8 is conventionally used. That is, strain gauges a, affixed to a plurality of measurement sites of an object such as a machine, a building, or a plurality of objects, respectively.
are connected via a connection line c to a strain measuring device A 'having a multipoint measuring function or to a switch box B controlled by the strain measuring device A'. Then, the strain gauge A ′ sequentially energizes the strain gauge a at each measurement point connected thereto to generate a measurement signal corresponding to the strain amount at the measurement point, and further connected to the switch box B. The strain gauge a at each measurement point is sequentially energized via the switch box B to generate a measurement signal corresponding to the amount of strain at the measurement point, and a measurement signal for each measurement point is obtained. Further, the strain measuring device A grasps the amount of strain at each measurement point based on the acquired measurement signal, and thereby performs multi-point strain measurement. In this case, for example, 1
For strain measurement by the gauge method,
And the switch box B, the resistance for constituting the Wheatstone bridge circuit as shown in FIG.
The multipoint strain measurement is performed while sequentially performing the switching connection for each measurement point.

However, in the above-described conventional strain measuring system, the following inconvenience is caused due to the connection line connecting the strain gauge to the strain measuring device or the switch box.

For example, in the measurement system according to the one-gauge method shown in FIG. 7, the resistance values r1 of the connection lines c1, c2 are set.
, R2, the Wheatstone bridge circuit h
Of the output voltage Δe (measurement signal) is Ra (=
R + ΔR) is replaced by Ra + r1 + r2, and when R1 = R2 = R3 = R as described above, the output voltage Δe is expressed by the following equation (2) ′.

Δe = [(ΔR + r1 + r2) / 2 (2R + ΔR + r1 + r2)] V (2) ′ As is apparent from the equation (2) ′, a connection line for connecting the strain gauge to a strain gauge or a switch box. Is the measurement sensitivity and the zero point of the strain measurement (the output voltage Δe which is the reference for the amount of strain, and this is generally the output voltage Δe when the strain gauge is attached to an object). The same applies to other strain measurement methods such as the two-gauge method and the four-gauge method.

For this reason, conventionally, the wire diameter and length of the connecting wire connecting the strain gauge to the strain gauge or the switch box (the resistance value of the connecting wire is basically determined by the wire diameter and length of the connecting wire). ), The measurement signal obtained at the time of strain measurement is corrected by adjusting the set value of the strain meter, or after the data value such as the amount of strain is finally obtained by the strain meter. In general, the measurer corrects the data value by referring to a correction table.

However, for example, in the above-described multi-point measurement, if the measurement points are wide, the connection line connecting the strain gauge to the strain gauge or the switch box must be long, and the connection line must be long. Tends to have a relatively large resistance value. In addition, even when a single point measurement of the amount of strain is performed, the connection line may have to be long due to the measurement environment. When the connection line is long and the resistance value is relatively large, it is difficult to secure sufficient measurement sensitivity and measurement accuracy even if the above-described correction is performed. I was

Further, since the resistance value of the connection line is affected by the environmental temperature, especially when the connection line is long and the resistance value is relatively large, the measurement signal or the like depends on the diameter and length of the connection line. If the correction is only performed, the zero point shifts and the measurement sensitivity fluctuate due to changes in the environmental temperature, making it difficult to perform long-term strain measurement and wide-range multi-point strain measurement with stable measurement accuracy. Was. In this case, 1
In the gauge method, by using a well-known one-gauge three-wire method,
Although the movement of the zero point can be suppressed to some extent, the fluctuation of the measurement sensitivity cannot be suppressed. In the 4-gauge method, the constant current method may be used in order to eliminate the influence of the resistance value of the connection line. However, this method is limited to the 4-gauge method.

Further, in the conventional measuring system, a signal (analog signal) corresponding to a minute resistance change of the strain gauge is used.
Is received via the connection line with the strain gauge on the strain measuring instrument side, it is easily affected by disturbance noise mixed into the connection line, deterioration of the connection line, etc., which is also a major factor of measurement error. Was. In particular, in strain measurement of structures, etc., there are many cases where connection wires are buried in the ground or long-term measurement is performed. In such cases, deterioration of the connection wires lowers their insulation properties and causes disturbance. Frequently, the noise was greatly increased and the measurement was seriously hindered.

As described above, in the conventional measurement system, the connection line connecting the strain gauge to the strain gauge or the switch box tends to have a bad influence on measurement accuracy, measurement stability, and the like.

In particular, in the case of multi-point measurement of a structure or the like, the number of measurement points may be hundreds, or even thousands in some cases. In order to correct the measurement signal and the finally obtained data value according to the diameter and length, the correction must be performed for each measurement point, and the temperature characteristics of the strain gauge at each measurement point must be corrected. In many cases, it is necessary to perform a correction in consideration of a thermal distortion characteristic according to the temperature of an object or a correction in consideration of each measurement point. Also, when installing the measurement system, it is necessary to wire the connection line between the strain gauge and the strain gauge or switch box at each measurement point, and when performing long-term measurement outdoors. Must be coated to protect the strain gauge, such as waterproofing the strain gauge at each measurement point.

Therefore, in the conventional multi-point strain measurement, these operations require enormous time, labor and cost, and
Inconveniences such as erroneous connection of connection lines are also likely to occur.

Further, in the conventional multi-point strain measurement, a measurement signal corresponding to the amount of strain is sequentially generated by a strain gauge at each measurement point, and the measurement signal is taken into a strain measuring instrument. In a large number of measurements, a relatively large time difference in the measurement timing of the strain amount at each measurement point occurs, and if the measurement environment changes within the time difference, the strain amount of each measurement point is measured under the same measurement environment conditions. It could not be measured.

[0020]

SUMMARY OF THE INVENTION In view of the foregoing, the present invention makes it possible to eliminate the adverse effects on the measurement accuracy and the measurement stability due to connection lines and to stably perform accurate strain measurement. It is still another object of the present invention to provide a strain measurement module capable of facilitating preparation work and measurement data processing for strain measurement.

Further, according to the present invention, in the multi-point strain measuring system, by using the strain measuring module, adverse effects on the measurement accuracy, the measurement stability, and the like due to the connection lines are eliminated, and the accurate measurement is stably performed. While enabling
It is another object of the present invention to provide a multi-point strain measurement system capable of facilitating preparation work and measurement data processing at the time of measurement, and further capable of efficiently collecting and processing measurement data.

[0022]

In order to achieve the above object, a strain measuring module according to the present invention includes a strain gauge attached to an object, and a measurement signal corresponding to at least the strain amount of the object by the strain gauge. , An A / D converter for converting the measurement signal into digital data, and digital data of the measurement signal, or a digital signal generated through a predetermined process. A module body unit integrally formed as a module with data output processing means for outputting digital data as measurement output data to the outside, and the module body unit is connected to the strain gauge in the vicinity thereof. Features.

According to the present invention, at least the measurement signal generation circuit, the A / D conversion means and the data output processing means are integrated into a module, and the module body is attached to the strain gauge. Since the connection is made in the vicinity of the strain gauge, the measurement signal generated by the strain gauge is transmitted to the A of the module main body in the vicinity of the strain gauge.
It is converted to digital data by the / D conversion means. In this case, since the connection line connecting the module main body to the strain gauge is short, the measurement signal is converted into digital data without being substantially affected by the resistance value of the connection line or disturbance noise. . Then, the digital data or digital data generated through predetermined processing from the digital data is output to the outside by the data output processing means of the module main body as measurement output data. At this time, since the measurement output data is digital data, the measurement output data is hardly affected by connection lines, disturbance noise, and the like, regardless of whether the data is output in a wired or wireless manner. Therefore, it is possible to accurately measure the distortion of the object using the measurement output data.

Therefore, according to the present invention, it is possible to stably perform accurate strain measurement by eliminating adverse effects on measurement accuracy, measurement stability, and the like due to connection wires.

In the strain measuring module according to the present invention, the strain gauge covered with a protective coating member for waterproofing the strain gauge, for example, is integrally mounted on the module main body. According to this, by attaching the strain gauge to the object, the coating process of the strain gauge and the installation of the module main body are performed, and the preparation work for strain measurement can be easily performed. In particular, when performing multipoint strain measurement on a plurality of objects or a plurality of parts of the objects using such a strain measurement module, the preparation work for each measurement point can be easily performed as described above. Thus, the overall preparation work can be effectively facilitated.

Alternatively, in the strain measuring module according to the present invention, the strain gauge covered with a protective coating member is detachably mounted on the module main body together with the coating member. A connecting portion for electrically connecting to the module body is provided on an outer surface of the coating member.
According to this, in a state where the strain gauge is attached to the module main body together with the coating member, the strain gauge is attached to the object, similarly to the above case, the coating processing of the strain gauge and the module main body. Preparatory work for strain measurement such as installation can be easily performed, and after completion of strain measurement, the strain gauge is removed from the module main body together with the coating member that covers it, and the module main body is reused can do. At the time of reuse, a strain gauge covered with a coating member having the connecting portion on the outer surface is attached to the module main body together with the coating member, so that the electrical connection of the strain gauge to the module main body is also achieved. It can be done easily.

Further, even if the strain gauge covered with the coating member as described above is not detachably mounted on the module main body together with the coating member, the strain gauge can be detachably mounted on the module main body. Is preferably connected to
The module body can be used repeatedly for strain measurement.

Further, in the strain measuring module according to the present invention, a temperature sensor for detecting a temperature of the object is provided, and the A / D conversion means includes means for converting a detection signal of the temperature sensor into digital data. The data output processing means includes means for externally outputting digital data of a detection signal of the temperature sensor.

According to this, the data of the temperature of the object often required for correction of the measurement data or the like at the time of strain measurement can be obtained by digital data together with the measurement output data.

In the distortion measuring module according to the present invention, digital data obtained by converting the measurement signal by A / D conversion means may be output to the outside as the measurement output data by the data output processing means. Preferably, when a temperature sensor for detecting the temperature of the object is provided, the A / D conversion means includes means for converting a detection signal of the temperature sensor into digital data, and the data output processing means Preferably includes means for correcting and outputting the measured output data based on the temperature of the object indicated by digital data of a detection signal of the temperature sensor.

That is, in the strain measurement, when it is necessary to perform correction in consideration of the temperature characteristic of the strain gauge, the temperature characteristic of the object, or the thermal strain of the object, to the measured value based on the measurement signal obtained by the strain gauge. In such a case, the data output processing means of the module main unit performs a process of correcting the measurement output data based on the temperature of the object indicated by digital data of the detection signal of the temperature sensor, By outputting it to the outside, desired data can be immediately obtained from the measured output data. For this reason, especially when performing multi-point strain measurement on a plurality of objects or a plurality of portions of the objects using the strain measurement module of the present invention, it is obtained from the data output processing means of the module main body corresponding to each measurement point. Post-processing of the measurement output data can be facilitated. In addition, since the above-described correction processing is independently performed for each measurement point by the data output processing unit of the module main body unit for each measurement point, the correction processing can be efficiently performed for each measurement point.

When the measured output data is corrected, in addition to the above-described correction in accordance with the temperature, correction based on characteristic values inherent to the strain gauge, such as the gauge factor of the strain gauge, and correction of the strain gauge to the object. The data output processing means may perform zero point correction (correction based on the level of the initial measurement signal) based on the digital data of the initially attached measurement signal.

In the strain measurement, a rosette gauge comprising at least three strain gauges is used as a strain gauge to be attached to an object, and a rosette analysis process is performed from data of measurement signals generated by each of the strain gauges. In some cases, the principal strain amount, the shear strain amount, and the direction of the principal strain of the object are measured by calculation.

Therefore, in the strain measuring module according to the present invention, when the strain gauge is a rosette comprising at least three strain gauges, the measurement signal generating circuit includes a circuit for each of the rosette gauges. Means for generating the measurement signal, the data output processing means, the main strain amount of the object from the digital data of the measurement signal for each strain gauge, the amount of shear strain,
And means for obtaining at least one of the directions of the principal strain by the rosette analysis processing as the measurement output data.

[0035] According to this, the data output processing means of the module main body determines the principal strain amount, shear strain amount, and principal strain direction of the object from the digital data of the measurement signal for each strain gauge. At least one,
Since it is obtained by the rosette analysis processing and output to the outside as measurement output data, it is necessary to immediately obtain desired data such as the main strain amount, shear strain amount, and main strain direction of the object from the measurement output data. Can be. In particular, when performing multi-point strain measurement on a plurality of objects or a plurality of portions of the objects using such a strain measurement module, measurement output data obtained from data output processing means of a module main body corresponding to each measurement point Post-processing can be facilitated. In addition, since the rosette analysis processing as described above is performed independently for each measurement point by the data output processing means of the module body unit for each measurement point, it is possible to efficiently perform the rosette analysis processing for each measurement point. it can.

Next, in order to achieve the above object, the multi-point strain measuring system of the present invention attaches a strain gauge to each of a plurality of objects or a plurality of portions of the objects, and uses the strain gauges to measure each object or each object. In a system for generating a measurement signal corresponding to the strain amount of each part of an object and performing multi-point strain measurement on a plurality of objects or on a plurality of parts of the object based on the measurement signals, affixed to at least each object or each part of the object. A measurement signal generation circuit for generating the measurement signal with the strain gauge attached thereto, A / D conversion means for converting the measurement signal into digital data, and digital data of the measurement signal or a predetermined signal from the digital data. And a data output processing means for externally outputting digital data generated through the above processing as measurement output data. A plurality of strain measuring modules each having a module main body connected to the object or a strain gauge for each part of the object in the vicinity thereof, and data output processing means of each strain measuring module. In order to collect and process the output measurement output data, the measurement output data is constituted by a data output processing means of each strain measurement module and a measurement data processing device communicably provided.

According to the present invention, by using the strain measurement module for each measurement point of each object or each part of the object to which the strain gauge is attached, as described above, the measurement accuracy and the stability of the measurement by the connection line can be improved. Eliminate adverse effects on sex, etc.
It is possible to stably perform accurate multipoint strain measurement.

Further, in the multipoint strain measuring system according to the present invention, the data output processing means of each of the strain measuring modules may alternatively output an output operation command unique to the strain measuring module from the measurement data processing device. The measurement output data is output to the measurement data processing device by giving it to the data output processing means.

As described above, by selectively giving an output operation command unique to each strain measurement module from the measurement data processing device to the data output processing means of each strain measurement module, the data output processing of each strain measurement module is performed. By outputting the measurement output data from the means to the measurement data processing device, the measurement output data for each measurement point can be efficiently collected in a time division manner by the measurement data processing device.

In this case, communication between the measurement data processing device and the data output processing means of each strain measurement module is as follows.
Although any of the wired and wireless methods may be adopted, the measurement output data for each measurement point can be collected in a time-division manner as described above. The measurement data processing device and the data output processing means of each strain measurement module are communicably connected via a common communication line. By thus connecting the measurement data processing device and the data output processing means of each strain measurement module via a common communication line, wiring processing between the measurement data processing device and each strain measurement module can be easily performed. Therefore, preparation work for multipoint strain measurement can be easily performed. Since the measurement output data exchanged between the measurement data processing device and each strain measurement module is digital data, the exchange of the data is not easily affected by the resistance value of the common communication line, disturbance noise, and the like. It goes without saying.

Further, when the measurement data processing device and the data output processing means of each strain measurement module are connected via a common communication line as described above, the measurement data processing device connects the common communication line. It is preferable to include a power supply unit for supplying power of each strain measurement module via the power supply unit, and a power supply unit for extracting power supply power of each strain measurement module from the common communication line in the module main body of each of the strain measurement modules. According to this, the power supply of each strain measurement module can be efficiently supplied via the common signal line without having to incorporate a power source such as a battery for each strain measurement module, Modules can be operated collectively only when necessary, such as during measurement.

Further, in the multipoint strain measuring system of the present invention, the data output processing means of each of the strain measurement modules includes a storage means for storing and holding the measurement output data, and each of the strain output modules provided by the measurement data processing device. The measurement output data based on the output of the A / D converter when the measurement start instruction is given in response to the measurement start instruction common to the measurement modules is stored in the storage, and the stored measurement output is stored. The data is output to the data processing device according to the output operation command.

According to this, by simultaneously giving a common measurement start command to each of the strain measurement modules provided from the measurement data processing device, the strain measurement modules at the respective measurement points use the digital data of the measurement signals at that time. The measurement output data is stored in the storage means. Then, the stored measurement output data is provided to the data output processing means of each strain measurement module by giving an output operation command specific to the strain measurement module from the measurement data processing device. The processing device is provided with measurement output data for each measurement point. Therefore, the measurement data processing device can obtain measurement output data based on the measurement signal for each measurement point at the same time.

In the multipoint strain measuring system according to the present invention, each strain measuring module preferably has the same configuration as the above-described strain measuring module according to the present invention.

That is, the strain gauges to be attached to the respective objects or the respective portions of the objects are integrally mounted on the module main body of each of the strain measurement modules in a state where the strain gauges are previously covered with a protective coating member.

Alternatively, the strain gauge to be attached to each object or each part of the object is detachably mounted together with the coating member on the module main body of each strain measurement module in a state where the strain gauge is previously covered with a protective coating member. A connecting portion for electrically connecting the strain gauge to the module main body in the mounted state is provided on the outer surface of the coating member.

Alternatively, a strain gauge attached to each object or each part of the object is detachably connected to a module main body of each strain measurement module.

In the case where a temperature sensor for detecting the temperature of each object or each part of the object is provided, the A / D conversion means of the strain measurement module converts a detection signal of the temperature sensor into digital data. Means to
The data output processing means of the strain measurement module,
Means for outputting digital data of a detection signal of the temperature sensor to the measurement data processing device.

Alternatively, when a temperature sensor for detecting the temperature of each object or each part of the object is provided, the A / D conversion means of the strain measuring module converts a detection signal of the temperature sensor into digital data. The data output processing means of the strain measurement module includes means for correcting and outputting the measured output data based on the temperature of the object indicated by digital data of a detection signal of the temperature sensor.

Further, in the case where the strain gauge adhered to each object or each part of the object is a rosette gauge comprising at least three strain gauges, the circuit for generating a measurement signal of each of the strain measurement modules includes: Means for generating the measurement signal for each strain gauge of the rosette gauge, wherein the data output processing means of the strain measurement module, the digital data of the measurement signal for each strain gauge of the rosette the object or each object or Means for obtaining at least one of a principal strain amount, a shear strain amount, and a principal strain direction of each part of the object by a rosette analysis process as the measurement output data is included.

By employing such a configuration of each strain measuring module, the above-described effects can be obtained.

[0052]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of a strain measuring module and a multi-point strain measuring system using the same according to the present invention will be described with reference to FIGS. FIG. 1 is a system configuration diagram showing an overall configuration of a multipoint strain measurement system according to the present embodiment, FIG. 2 is a circuit configuration diagram of a strain measurement module used in the system of FIG. 1, and FIG. FIG. Reference numerals in parentheses in FIG. 1 correspond to a second embodiment described later, and are not used in the following description of the first embodiment.

Referring to FIG. 1, the multipoint strain measuring system according to the present embodiment measures the strain amount of a plurality of portions of an object (not shown) such as a building or a machine by, for example, a 1-gauge method. , A plurality of strain gauges 1 attached to each part (each measurement point) of the object, and a plurality of strain measurement modules formed by connecting the module body 2 to the strain gauges 1 at each measurement point. , And a measurement data processing device 4 for collecting and processing measurement output data generated by each strain measurement module 3 as described later.

In this case, in this embodiment, the set of the strain gauge 1 and the strain measurement module 3 at each measurement point is classified into a plurality of groups G, G,. The module body 2 is connected to a common sub-communication line 5 for each group G. These sub communication lines 5 join a common main communication line 6 for all the groups G, G,.
Are connected to the measurement data processing device 4. Thereby, the module main body 2 of each strain measurement module 3
Communicates data with the measurement data processing device 4 via a sub-communication line 5 common to the group G to which it belongs and a main communication line 6 common to all groups G, G,. Can be performed.

In the present embodiment, the above grouping is performed.
May be connected to the measurement data processing device 4 via a single common communication line (this is the same in other embodiments described later).

Each of the strain measurement modules 3 is a module in which a required circuit is formed into a small module using a one-chip microcomputer or the like, and a module body 2 is connected to the strain gauge 1 in the vicinity thereof. It has a circuit configuration as shown.

That is, the module main body 2 is composed of three resistors 8, 8, 8 connected together to form a Wheatstone bridge circuit 7 together with the strain gauge 1 connected thereto, and the Wheatstone bridge circuit 7 , A bridge power supply circuit 9 for applying an input voltage V (constant voltage) between a pair of diagonal points, and an output voltage generated between the remaining pair of diagonal points of the Wheatstone bridge circuit 7 when the input voltage V is applied. Δe, that is, an amplifier 10 for amplifying a measurement signal corresponding to the amount of distortion at a measurement point, and an A / D for converting the output of the amplifier 10 to digital data representing the level thereof
A converter 11 (A / D conversion means). here,
According to the configuration of the present invention, the Wheatstone bridge circuit 7, the bridge power supply circuit 9, and the amplifier 10 constitute a measurement signal generation circuit 12.

The resistance of each resistor 8 of the Wheatstone bridge circuit 7 is, for example, the same as the normal resistance of the strain gauge 1.

Further, the module main unit 2 is provided with a control circuit (CPU) 13 for performing overall operation control and arithmetic processing.
And a storage circuit 14 (storage means) for storing and holding programs and various data for the control circuit 13, and an interface circuit 15 for transmitting and receiving data to and from the measurement data processing device 4.

Here, the control circuit 13 constitutes the data output processing means 16 in combination with the storage circuit 14 and the interface circuit 15. The operation of the control circuit 13 will be described in detail later. The measurement signal Δ from the A / D converter 11 according to a command given from the device 4.
The digital data of e is acquired to generate required measurement output data, which is output from the interface circuit 15 to the measurement data processing device 4 via the sub communication line 5 and the main communication line 6.

The storage circuit 14 includes a ROM in which a program and the like for the control circuit 13 are stored and held in advance, a RAM in which the measurement output data generated by the control circuit 13 is stored and held, and the control circuit 13 stores the measurement output data and the like. E that stores and retains parameter data and the like used to generate
And an EPROM. In this case, EEP
The ROM previously stores identification data (ID code) unique to each strain measurement module 3 and a gauge factor K unique to the strain gauge 1 connected to the module body 2 as described later.
Are stored and held.

Further, in this embodiment, the operating power supply of each strain measuring module 3 is collectively transmitted from the measurement data processing device 4 to the module main body of each strain measuring module 3 via the main communication line 6 and the sub communication line 5. The module main body 2 extracts the operating power supply power from the sub communication line 5 connected thereto and supplies it to the respective circuits such as the control circuit 13 and the like. A main power supply circuit 17 (power supply means) is provided.

In each strain measuring module 3 of the present embodiment, the strain gauge 1 and the module main body 2 having the above-described circuit configuration are connected in a structure as shown in FIG. That is, the strain gauge 1 of each strain measurement module 3 is covered with a protective coating member 18 for waterproofing or the like, except for a surface to be stuck to an object, and the coating member 18 is formed in a block shape. . And the strain gauge 1 is the coating member 1
8 and a connection wire 19 derived from the strain gauge 1 is connected to the module main body 2 by soldering or the like. Further, the module main body 2 and the coating member 18 are attached to the open end of the bottomed cylindrical housing 20 by the strain gauge 1.
And is housed in the housing 20. With such a structure, the strain gauge 1 is integrally mounted on the module main body 2 and the module main body 2
(Specifically, one side of the Wheatstone bridge circuit 7)
Are electrically connected to the strain gauge 1 in the vicinity thereof.

The measurement data processing device 4 is constructed by using a microcomputer, and its operation will be described in detail later. However, basically, the main unit 2 of each strain measurement module 3 A predetermined command is given while power is supplied through the communication line 6 and the sub communication line 5 to generate and output measurement output data, and the measurement output data is collected. Then, the measured value indicated by the collected measurement output data is displayed on a display (not shown) or recorded on a recording device (not shown).

Next, the operation of the multi-point strain measuring system of the present embodiment (including the operation of the strain measuring module) will be described.

When performing multi-point strain measurement on a plurality of parts of an object such as a building or a machine by the system of the present embodiment, each of the parts (each measurement point) of the object is provided with each of the strain measurement modules 3. The strain gauge 1 is attached to an adhesive (not shown) (see FIG. 3). In this case, as described above, the strain gauge 1 is covered with the coating member 18 and is integrally attached to the module main body 2 of each strain measurement module 3 together with the coating member 18. By attaching the strain gauge 1 to each part of the object, the coating process for waterproofing the strain gauge 1 and the installation of the module main body 2 are performed.

Further, the module body 2 of the strain measurement module 3 at each measurement point and the measurement data processing device 4
Are connected via the sub communication line 5 and the main communication line 6.

After the completion of such preparation work, by performing a predetermined operation of the measurement data processing device 4, the measurement data processing device 4 is connected to each measurement point via the main communication line 5 and the sub communication line 6. While supplying power to the strain measuring modules 3, a predetermined initial setting operation command for performing the initial setting process is transmitted to the module main body 2 of each strain measuring module 3. This initial setting operation command is transmitted to all the strain measurement modules 3 via the main communication line 5 and the sub communication line 6.
In this case, the following initial setting process is performed in the module main body 2.

That is, when the control circuit 13 of each strain measurement module 3 receives the initial setting operation command via the interface circuit 15, the control circuit 13 applies the input voltage V from the bridge power supply circuit 9 to the Wheatstone bridge circuit 7, The measurement signal Δe according to the amount of distortion at the measurement point
Is generated. The control circuit 13 converts the level of the measurement signal Δe amplified by the amplifier 10 into an A / D signal.
The converter 11 converts the data into digital data, and stores the digital data of the measurement signal Δe, that is, the initial value of the measurement signal Δe as data representing the zero point of strain measurement (the level of the measurement signal Δe used as a reference of the strain amount). 14 is stored in the EEPROM.

After performing the initial setting process in each strain measurement module 3 in this manner, when measuring the strain amount at each measurement point, a predetermined operation of the measurement data processing device 4 is performed. The measurement data processing device 4 sends a predetermined measurement start command for generating measurement output data to the module main body 2 of each strain measurement module 3 while supplying power to the strain measurement module 3 at each measurement point. I do. This measurement start command is given to the module main units 2 of all the strain measurement modules 3 at substantially the same time via the main communication line 6 and the sub communication line 5, and at this time, the module main unit 2 performs the following processing. Is performed.

That is, when the control circuit 13 of each strain measurement module 3 receives the initial setting operation command via the interface circuit 15, the control circuit 13 applies the input voltage V from the bridge power supply circuit 9 to the Wheatstone bridge circuit 7, The measurement signal Δe is generated. Then, the control circuit 13 compares the level of the measurement signal Δe with the amplifier 10.
Is converted into digital data by the A / D converter 11, and digital data of the measurement signal Δe is obtained. Further, the control circuit 13 starts the measurement signal Δe previously stored in the EEPROM from the current level of the measurement signal Δe indicated by the acquired digital data.
The zero value is corrected by subtracting the initial value of e, and from the level of the zero-corrected measurement signal Δe, for example, the calculation of the above equation (4) ′ is performed to obtain the distortion amount ε at the measurement point.
(The amount of strain in the usual sense) is calculated. In this case, the value of the gauge factor K stored in advance in the EEPROM (this value is a characteristic value unique to the strain gauge 1) is used for this calculation. Then, the control circuit 13
Measured output data (digital data)
Is stored in the RAM of the storage circuit 14.

As a result, in the module main body 2 of each strain measurement module 3, measurement output data based on the measurement signal Δe for each measurement point is generated and stored almost simultaneously.

Next, by performing a predetermined operation of the measurement data processing device 4, the measurement data processing device 4 supplies power to the strain measurement modules 3 at the respective measurement points, The identification data (ID code) unique to (i.e., in order)
A predetermined output operation command including the selected identification data is transmitted. This output operation command is a command for causing each of the strain measurement modules 3 to output the measurement output data generated and stored as described above, and the main communication line 6 and the sub communication Provided via line 5.

At this time, the following processing is performed in the module main body 2 of each strain measurement module 3.

That is, when the control circuit 13 of the module body 2 receives the output operation command via the interface circuit 15, the control circuit 13 stores the identification data included in the command into the identification data stored in the EEPROM of the storage circuit 14. And wait if they do not match. If they match, the control circuit 13 sends out the measurement output data previously stored and held in the RAM of the storage circuit 14 via the interface circuit 15. Therefore, the module main body 2 of each strain measurement module 3 sends out the measurement output data only when an output operation command including identification data unique to the strain measurement module 3 is given.

The measurement data processing device 4 receives the measurement output data sent from each of the strain measurement modules 3 as described above, thereby dividing the measurement output data for each measurement point from each of the strain measurement modules 3 in a time division manner. To collect.

The measurement data processing device 4 displays the amount of distortion at each measurement point indicated by the measurement output data at each measurement point collected as described above on a display (not shown) or records it on a recording device. As described above, multipoint strain measurement is performed.

When performing long-term measurement, the generation and output of the measurement output data in each of the strain measurement modules 3 described above are repeated at appropriate time intervals.

In the measuring system of this embodiment, the module main body 2 of each strain measuring module 3
Is connected to the strain gauge 1 in the vicinity,
The connection line 19 may be very short. Therefore, the measurement signal Δe corresponding to the amount of distortion at the measurement point is generated without being substantially affected by the resistance value of the connection line 19, disturbance noise, or the like. Can be converted to data. Then, the measurement output data based on the digital data is transmitted from each of the strain measurement modules 3 to the measurement data processing device 4.
Since the measured output data is digital data, the measured output data is the digital data, which is used to determine the resistance and disturbance of the sub-communication line 5 and the main communication line 6 connecting each strain measurement module 3 and the measurement data processing device 4. It is hardly affected by noise and the like.

Therefore, it is possible to accurately measure the amount of strain at each measurement point while eliminating the adverse effect on the measurement accuracy and the measurement stability due to the connection line, and to stably perform the measurement. .

In this embodiment, since each strain measuring module 3 has an integral structure of the strain gauge 1, the coating member 18 covering the strain gauge 1, and the module main body 2, the strain gauge 1 can measure the object. By sticking to the points, the coating process of the strain gauge 1 and the installation of the module main body 2 are performed, so that the preparation work for each measurement point can be easily performed. Furthermore, in the present embodiment, the measurement output data for each measurement point by the measurement data processing device 4 can be collected in a time-division manner using identification data unique to each strain measurement module 3. Acquisition can be performed efficiently, and at the same time, each strain measurement module 3 and measurement data processing device 4
The connection can be made by a common main communication line 6 and sub-communication line 5, so that the wiring processing can be easily performed.

In the present embodiment, the module body 2 of each strain measurement module 3 acquires digital data of the measurement signal Δe in response to a measurement start command from the measurement data processing device 4 and outputs a measurement output based on the digital data. Since the data is stored and held in the storage circuit 14, measurement output data based on the measurement signal Δe at each measurement point at the same time can be obtained.

Furthermore, in the present embodiment, the measurement signal Δ
In order to generate the measurement output data by correcting the zero point of the data e and calculating the strain amount ε, it is necessary to perform the initial setting for each measurement point or calculate the strain amount ε on the measurement data processing device 4 side. Therefore, initial setting and post-processing at the time of measurement can be easily performed. Moreover, since the above-mentioned zero correction and the calculation of the strain ε are performed independently and in parallel in the module body 2 of each strain measurement module 3, the zero correction and the calculation of the strain ε for each measurement point are performed. It can be performed efficiently.

In this embodiment, the strain gauge 1 is covered with the coating member 18 and is integrally mounted on the module main body 2. However, in the case of indoor measurement or short-term measurement, When it is not necessary to perform the coating process on the strain gauge 1, the strain gauge 1 may be directly connected to the module main body 2 in the vicinity thereof by soldering or the like. In this case, the module main body 2 may be installed by attaching the module main body 2 to an appropriate position near the strain gauge 1 using, for example, an appropriate mounting member.

Next, a second embodiment of the present invention will be described with reference to FIG. In this embodiment, only a part of the structure of the strain measurement module is different from that of the first embodiment, and the same portions are denoted by the same reference numerals and drawings as those of the first embodiment. Detailed description is omitted.

FIG. 4 is a sectional view showing the structure of the strain measuring module 21 according to the present embodiment. In this strain measuring module 21, the strain gauge 1 attached to an object is used.
Is covered with a block-shaped coating member 18 as in the first embodiment. The coating member 18 is a bottomed cylindrical housing 20 that houses the module body 2 (the circuit configuration is as shown in FIG. 2) at the bottom.
The coating member 18 is attached to the housing 2 such that the strain gauge 1 is positioned at the open end of the housing 20.
By inserting the module body 0 toward the module body 2,
The strain gauge 1 is mounted on the housing 20 together with the coating member 18.
And is detachably attached to the module main body 2 via the.

In this case, the connection wire 19 derived from the strain gauge 1 is connected to an electrode piece 22 attached to the outer surface of the coating member 18 facing the module body 2. The electrode piece 22 constitutes a connection part for electrically connecting the strain gauge 1 to the module main body 2, and as described above, the coating member 18 is connected to the housing 20.
In a state of being inserted and mounted inside, it comes into contact with an electrode piece 23 provided in advance on the module main body 2, whereby
The strain gauge 1 is electrically connected to the module body 2. In this embodiment, the electrode piece 23 of the module body 2 is connected to the Wheatstone bridge circuit 7 shown in FIG.
Is conducted to one side.

The multi-point strain measuring system of the present embodiment using such a strain measuring module 21 has the same configuration as that of the first embodiment (see FIG. 1). In a state where the strain gauge 1 attached to each measurement point is attached to the module body 2 of FIG. 21 together with the coating member 18 covering the same, the first
This is performed in exactly the same manner as in the first embodiment.

In this case, in this embodiment, the same operation and effect as those of the first embodiment can be obtained, and the following operation and effect can be obtained.

That is, in the strain measurement module 21 of the present embodiment, as described above, the strain gauge 1 and the coating member 18 are detachably mounted on the module main body 2 (see FIG. 4), and thus the measurement is completed. Later, by removing the coating member 18 from the housing 20 of each strain measurement module 21, the coating member 18 is removed.
In addition, the strain gauge 1 covered by this can be removed. And the coating member 18 is thus
If the strain gauge 1 is removed, the module main body 2 of the strain measurement module 21 can be reused. In addition, when reusing the module, as shown in FIG. 4, the coating member 18 is covered with the coating member 18 and the coating member 18 is simply inserted into the housing 20 and mounted. 2 can also be made immediately by the contact of the electrode pieces 22, 23.

In the present embodiment, a connecting portion for electrically connecting the strain gauge 1 to the module body 2 is
Although the one using the contact type electrode piece 22 is shown, for example, when the coating member 18 covering the strain gauge 1 is mounted on the module main body 2, a connector that fits and connects to the module main body 2 is used. You may make it comprise the said connection part.

In the present embodiment, the strain gauge 1 is covered with the coating member 18 and is detachably mounted on the module main body 2. However, in the case of indoor measurement or short-term measurement, When it is not necessary to perform the coating process on the strain gauge 1, the strain gauge 1 may be detachably connected to the module main body 2 in the vicinity thereof, for example, via a connector. And
In this case, the module main body 2 may be installed by, for example, mounting the module main body 2 at an appropriate position near the strain gauge 1 using an appropriate mounting member.

In the first and second embodiments described above, the multipoint measurement of the strain amount ε in the ordinary sense is shown. However, the module main body 2 of each of the strain measurement modules 3 and 21 has been described. In, the amount of strain ε is obtained from the digital data of the measurement signal Δe, and the stress at each measurement point is calculated as the measurement output data from the strain amount ε by, for example, the calculation of the equation (5), and the stress at each measurement point is measured. You may do so. In this case, the Young's modulus of the object necessary for obtaining the stress may be stored in, for example, an EEPROM of the storage circuit 14 of each of the strain measurement modules 3 and 21.

In the first and second embodiments, each of the strain measurement modules 3 and 21 obtains the amount of distortion from the digital data of the measurement signal Δe, and outputs it to the measurement data processing device 4 as measurement output data. As described above, the digital data of the measurement signal Δe is output to the measurement data processing device as it is, and the measurement data processing device calculates the amount of strain (including stress) at each measurement point from the digital data of the measurement signal Δe. You may make it. Even in this case, accurate and stable measurement can be performed without the influence of the connection line.

Next, a third embodiment of the present invention will be described with reference to FIG. Note that the present embodiment differs from the first or second embodiment only in part of the configuration and function of the strain measurement module, and the same components are the same as those in the first or second embodiment. Detailed description will be omitted using the same reference numerals and drawings.

FIG. 5 shows a circuit configuration of the strain measuring module 24 according to the present embodiment. In this strain measuring module 24, the strain gauge 1 to be attached to a measurement point of an object is attached to the module main body 25 in the vicinity thereof. In addition to the connection, a temperature sensor 26 (for example, a thermocouple) is attached to the object near the strain gauge 1 to detect the temperature of the object, and the temperature sensor 26 is connected to the module main body 25. .

In this case, the module main body 25 includes the circuit configuration shown in FIG. 2, that is, the Wheatstone bridge circuit 7 (including the resistors 8, 8, 8), the bridge power supply circuit 9, the amplifier 10, the A / D Converter 11, control circuit 1
3, a switch 27 in addition to the storage circuit 14, the interface circuit 15, and the main power supply circuit 17. The switch 27 converts the measurement signal Δe generated by the Wheatstone bridge circuit 7 connected to the strain gauge 1 into an amplifier 1
A signal amplified by 0 and a detection signal of the temperature sensor 26 (hereinafter, referred to as a temperature detection signal) are input, and the measurement signal Δe and the temperature detection signal are selectively switched by the control of the control circuit 13 to control the A / A Output to the D converter 11,
They are converted to digital data.

In this embodiment, the control circuit 13
As will be described in detail later, the measurement output data is generated by correcting the amount of strain grasped from the digital data of the measurement signal Δe according to the temperature indicated by the digital data of the temperature detection signal.

The structure of the strain measuring module 24 in the present embodiment is similar to that of the first or second embodiment, for example, with respect to the strain gauge 1 and the temperature sensor 2.
It is preferable that both of them are covered with a block-shaped coating member and are attached to the module main body 25 integrally or detachably. Alternatively, both or one of the strain gauge 1 and the temperature sensor 26 may be simply connected to the module main body 25 in the vicinity of the module main body 25 via a connection line or a connector.

The configuration of the multi-point strain measuring system according to the present embodiment using such a strain measuring module 24 is basically the same as the system configuration of the first embodiment. For example, each system shown in FIG. Strain measurement module 3
Is replaced by the strain measurement module 24 of the present embodiment. Therefore, in the description of the present embodiment,
For the system configuration excluding the strain measurement module,
The same reference numerals as in FIG. 1 are used.

In the multipoint strain measuring system of the present embodiment, the module main body 25 of the strain measuring module 24 at each measuring point receives the measurement start command from the measurement data processing device 4 described in the first embodiment. The measurement output data is generated as follows.

That is, the control circuit 13 of the module body 25 sequentially switches the switch 27 to the Wheatstone bridge circuit 7 side and the temperature sensor 26 side, and sequentially converts the measurement signal Δe and the temperature detection signal to an A / D converter. The data is converted into digital data by 11 and the digital data is acquired.

Next, as described in the first embodiment, the control circuit 13 obtains the strain amount ε by, for example, the equation (4) ′. Here, for example, in a measurement environment condition in which the temperature of the object changes relatively largely (in a measurement under such conditions, a so-called high-temperature strain gauge is generally used as the strain gauge 1), the data of the measurement signal Δe Includes the components due to the thermal strain of the object, the thermal strain of the strain gauge 1 itself, and the like, in addition to the external stress acting on the object. The measurement sensitivity also changes due to the temperature characteristics of the strain gauge 1 and the like.

Therefore, in the present embodiment, the control circuit 13 of each strain measurement module 24 performs a correction operation of the following equation (6) by using the temperature t indicated by the digital data of the temperature detection signal. Find the true strain εx due to external stress.

Εx = (ε−apparent strain at temperature t) · k (t) (6) Here, the apparent strain in the equation (6) is a value in a state where no true strain is generated in the object due to external stress. , A strain amount (strain amount in a normal sense) grasped from a measurement signal Δe appearing due to factors other than external stress such as a thermal strain of an object and a thermal strain of the strain gauge 1 itself. The value at the temperature t is obtained from the temperature t based on the temperature detection signal using a data table, an arithmetic expression, or the like stored in advance in the EEPROM of the storage circuit 14 for each of the strain measurement modules 24, for example. Further, k (t) in the equation (6) is a coefficient (a function of the temperature t) for correcting the measurement sensitivity. The value of the correction coefficient k (t) is also stored in the storage circuit for each strain measurement module 24. The data is obtained from the temperature t based on the temperature detection signal by using a data table, an arithmetic expression, and the like stored in advance in the EEPROM 14.

The contents stored in the EEPROM are as follows.
It may be rewritten at any time according to the purpose or necessity.

Then, the control circuit 13 of each strain measuring module 24 calculates the true strain ε obtained as described above.
The data x (digital data) is stored and held in the RAM of the storage circuit 14 as the measurement output data, and the stored measurement output data is transmitted from the measurement data processing device 4 to each strain measurement device 4 in the same manner as in the first embodiment. When the output operation command including the identification data for each module 24 is given, it is output to the measurement data processing device 4 via the sub communication line 5 and the main communication line 6 (in this case, if necessary, the temperature Digital data of the detection signal may also be output.)

As a result, on the measurement data processing device 4 side,
Data indicating the true strain amount εx of the object at each measurement point is obtained.

According to such an embodiment, the first
Alternatively, in addition to having the same operation and effect as the second embodiment,
In the distortion measurement module 24 at each measurement point, the correction processing according to the temperature t of the object is performed, so that the measurement data processing device 4 does not need to perform the correction processing according to the temperature for each measurement point, and Processing becomes extremely easy.
Moreover, since the correction processing according to the temperature t of the object at each measurement point is performed independently and in parallel in each strain measurement module 24, the correction processing can be performed efficiently.

In the present embodiment, the correction processing according to the temperature t of the object is performed as described above. However, the true distortion amount εx
Is required, the EEPROM of the storage circuit 14 is used.
The linear expansion coefficient (/ ° C.) of the object is stored and held in advance, and the initial value of the temperature t of the object is stored in the storage circuit 1 during the initial setting process as described in the first embodiment.
4, the thermal strain of the object is obtained from the deviation between the initial value and the present value of the temperature t and the linear expansion coefficient at the time of measurement, and the thermal strain is subtracted from the strain ε to obtain the true value. May be obtained.

In this embodiment, the true strain εx
Although (the amount of distortion in a normal sense) is obtained as the measurement output data, for example, the Young's modulus E of the object is stored in advance in the EEPROM of the storage circuit 14 as a function of the temperature t using a data table, an arithmetic expression, or the like. At the same time,
From the temperature t based on the temperature detection signal at the time of measurement, the Young's modulus E at the temperature t is obtained, and the obtained Young's modulus E is multiplied by the true strain amount εx to obtain the external stress acting on the measurement point of the object. You may do so. Then, the obtained external stress may be output from the module main body 25 of the strain measurement module 24 as measurement output data.

Further, when the stress acting on the measuring point of the object is known in advance (for example, when the stress is constant), the strain measuring module at each measuring point is reversed, contrary to the present embodiment. In, it is also possible to determine the thermal strain of the object as measurement output data.

In the present embodiment, the correction processing according to the temperature t of the object is performed in each strain measurement module 24. However, the digital data of the measurement signal Δe is sent from the module main body 25 of each strain measurement module 24. Alternatively, digital data of the temperature detection signal may be output to the measurement data processing device 4 together with the data of the strain amount ε based thereon, and the measurement data processing device 4 may perform the above-described correction processing. Even in such a case, since the data provided from each strain measurement module 24 to the measurement data processing device 4 is digital data,
It is possible to eliminate the influence of the connection lines between them (the sub communication line 5 and the main communication line 6) and to stably perform accurate measurement with high accuracy.

Further, when the measurement is performed using the strain measurement module 24 of the present embodiment under the measurement environment condition in which the temperature of the object changes relatively largely, the module body 25 is hardly affected by the temperature. It is preferable to have a structure or to be installed at a location that is hardly affected by temperature.

In the first to third embodiments described above, the measurement by the one-gauge method has been described.
A gauge method or a 4-gauge method may be used. In this case, the first
Since the 1-gauge method is used in the third to third embodiments,
Although three resistors 8, 8, 8 are provided in the module main body 2, 25, for example, in the measurement by the two-gauge method, two resistors are used in order to form a Wheatstone bridge circuit together with two strain gauges. For example, in the measurement by the 4-gauge method, since a Wheatstone bridge circuit is constituted by four strain gauges, it is not necessary to provide a resistor.

Next, a fourth embodiment of the present invention will be described with reference to FIG. Note that the present embodiment differs from the first or second embodiment only in part of the configuration and function of the strain measurement module, and the same components are the same as those in the first or second embodiment. Detailed description will be omitted using the same reference numerals and drawings.

FIG. 6 shows a circuit configuration of the strain measuring module 28 according to the present embodiment. In this strain measuring module 28, three strain gauges 1a, 1b, and 3a are attached to measurement points of an object. A rosette gauge 29 made of 1c is connected to the module body 30 in the vicinity thereof. In addition, the rosette gauge 29 of the present embodiment includes three strain gauges 1a, 1b, 1c.
A so-called right-angled rosette is used, which is attached to an object by shifting the azimuth by 5 °.

In this case, the module main body 30 has the circuit configuration shown in FIG. 2, that is, the Wheatstone bridge circuit 7 (including the resistors 8, 8, 8), the bridge power supply circuit 9, the amplifier 10, the A / D Converter 11, control circuit 1
3, a switch 31 in addition to the storage circuit 14, the interface circuit 15, and the main power supply circuit 17. The switching device 31 is interposed between the three strain gauges 1a, 1b, 1c of the rosette gauge 29 and the resistors 8, 8, 8 to form the strain gauges 1a, 1b, 1c (strain gauges 1a, 1b, 1c for conducting to the resistors 8, 8, 8)
Is selectively and sequentially switched by the above control.

In this embodiment, the control circuit 13
Although the details will be described later, each of the strain gauges 1a, 1b, and 1c of the rosette gauge 29 is sequentially connected to the resistors 8, 8, and 8 via the switch 31, and a measurement signal Δe is generated for each of the strain gauges 1. Then, from the digital data of the measurement signal Δe, the principal strain amount, the shear strain amount, and the direction of the principal strain of the object at each measurement point are obtained as measurement output data.

As to the structure of the strain measuring module 28 in the present embodiment, for example, the rosette gauge 29 is covered with a block-shaped coating member and the module main body 30 is formed in the same manner as in the first or second embodiment. It is preferable to mount it integrally or detachably. Alternatively, each strain gauge 1 of the rosette gauge 29
The components a, 1b, and 1c may be simply connected to the module main body 30 in the vicinity of the module main body 30 via connection wires or connectors.

The configuration of the multi-point strain measuring system according to the present embodiment using such a strain measuring module 28 is basically the same as the system configuration of the first embodiment. For example, each system shown in FIG. Strain measurement module 3
Is replaced by the strain measurement module 28 of the present embodiment. Therefore, in the description of the present embodiment,
For the system configuration excluding the strain measurement module,
The same reference numerals as in FIG. 1 are used.

In the multi-point strain measuring system of this embodiment, the module main body 30 of the strain measuring module 28 at each measuring point receives the measurement start command from the measurement data processing device 4 described in the first embodiment. The measurement output data is generated as follows.

That is, the control circuit 13 of the module main unit 30 sequentially switches the switch 29 to generate the measurement signal Δe for each of the strain gauges 1a, 1b, 1c, and transmits it to the A / D converter 11 To obtain the converted digital data.

Next, the control circuit 13 determines, based on the data of the measurement signal Δe for each of the strain gauges 1a, 1b, 1c, as in the case of the first embodiment, each of the strain gauges 1a, 1a, 1c.
The strain amounts εa, εb, εc corresponding to 1b and 1c are obtained.

Further, the control circuit 13 determines the amount of distortion ε
From the a, εb, and εc, the maximum shear strain γmax and the maximum principal strain εmax are applied to the object at each measurement point by a known calculation (rosette analysis processing) of the following equations (7) to (10).
And the minimum value εmin, and the angle ψp from the strain gauge 1a to the direction of the principal strain (the angle between the direction of the strain gauge 1a and the direction of the principal strain).

Γmax = [2 ｛(εa−εc) ² + (εb−εc) ² ｝] ^1/2 (7) εmax = (εa + εb + γmax) / 2 (8) εmin = (εa + εb) −γmax) / 2 (9) ψp = (1/2) tan ⁻¹ [(2εc−εa−εb) / (εa−εb)] (10) Then, the control circuit 13 The maximum shear strain amount γmax, the principal strain maximum value εmax and the minimum value εmin, and the angle ψp from the strain gauge 1a to the direction of the principal strain are stored and held in the RAM of the storage circuit 14 as measurement output data. And outputs it to the measurement data processing device 4 in response to an output operation command from the measurement data processing device 4 as in the first embodiment.

Thus, in the measurement data processing device 4,
For each measurement point, the maximum shear strain amount γmax, the maximum value εmax and the minimum value εmin of the principal strain amount, and the strain gauge 1
Data of the angle ψp from a to the direction of the principal strain is obtained.

According to the present embodiment, the first
Alternatively, in addition to having the same operation and effect as the second embodiment,
Since the rosette analysis processing is performed in the strain measurement module 28 at each measurement point, the maximum shear strain amount γmax, the maximum value εmax and the minimum value εmin of the main strain amount, and the strain Gauge 1a
There is no need to perform a process for obtaining the angle ψp from the direction of the principal strain to the direction of the main strain, and post-processing becomes extremely easy. Moreover, since the rosette analysis processing for each measurement point is performed independently and in parallel in each strain measurement module 28, the rosette analysis processing can be performed efficiently.

In the present embodiment, the rosette gauge 29
Although a right-angle rosette was used as a delta rosette, a delta rosette using three strain gauges, a double right-angle rosette using four strain gauges in order to further improve measurement accuracy, and a T-delta rosette are also known. And these methods may be adopted.

In the present embodiment, the maximum shear strain γmax, the maximum value εmax and the minimum value εmin of the main strain, and the angle ψp from the strain gauge 1a to the direction of the main strain are obtained for each measurement point. However, if necessary, some of these may be omitted (for example, the maximum shear strain amount γmax may not be obtained).

In this embodiment, the maximum shear strain γmax, the maximum value εmax and the minimum value εmin of the main strain are set.
Is obtained as the measurement output data. However, the maximum shear stress and the minimum and maximum values of the main stress are subjected to rosette analysis processing (the arithmetic expression in this case is omitted here but is known).
Thus, each strain measurement module may obtain the measurement output data.

Further, in the present embodiment, similarly to the third embodiment, each strain measuring module 28 may be provided with a temperature sensor, and may perform a correction process based on a detected temperature to obtain a main strain amount and the like. .

In each of the first to fourth embodiments described above, the strain measurement modules 3, 21, 24, 28
Are connected to the measurement data processing device 4 via the common communication lines 5 and 6. However, in order to eliminate the influence of the connection lines and perform accurate and stable measurement, each of the strain measurement modules 3 and 21, 24, and 28 may be connected to the measurement data processing device via separate communication lines. Further, communication between each of the strain measurement modules 3, 21, 24, and 28 and the measurement data processing device 4 may be performed wirelessly.

Further, in each of the first to fourth embodiments, the measurement of the strain amount of a plurality of parts of an object such as a building has been described, but the multipoint measurement of the strain amount of a plurality of objects is performed. It goes without saying that the strain measurement module and the multipoint strain measurement system of the present invention can also be applied to this.

Further, in each of the first to fourth embodiments, the power source of each of the strain measurement modules 3, 21, 24, and 28 is supplied from the measurement data processing device 4 collectively. Measurement modules 3, 21, 24
A power battery may be built in every 28.

In each of the first to fourth embodiments, each of the strain measurement modules 3, 21, 24, and 28 is applied to multipoint strain measurement. The present invention can also be applied to a case where a single point measurement of a distortion amount of an object is performed.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram showing an overall configuration of a multipoint strain measurement system according to first and second embodiments of the present invention.

FIG. 2 is a circuit configuration diagram of a strain measurement module used in the system of FIG. 1 in the first embodiment of the present invention.

FIG. 3 is a sectional view showing the structure of the strain measurement module of FIG. 2;

FIG. 4 is a sectional view showing a structure of a strain measurement module according to a second embodiment of the present invention.

FIG. 5 is a circuit configuration diagram of a strain measurement module according to a third embodiment of the present invention.

FIG. 6 is a circuit configuration diagram of a strain measurement module according to a fourth embodiment of the present invention.

FIG. 7 is a circuit diagram for explaining the principle of strain measurement by the one-gauge method.

FIG. 8 is a configuration diagram of a conventional multipoint strain measurement system.

[Explanation of symbols]

1, 1a to 1c: strain gauge, 2, 25, 30: module body, 3, 21, 24, 28: strain measurement module, 4: measurement data processing device, 5, 6: communication line, 1
DESCRIPTION OF SYMBOLS 1 ... A / D converter, 12 ... Measurement signal generation circuit, 14 ...
Storage circuit (storage means), 16 data output processing means, 1
7: Main power supply circuit (power supply means), 18: Coating member, 22: Electrode piece (connection portion), 26: Temperature sensor, 29
... Rosette gauge.

Claims (12)

[Claims] 1. A strain gauge attached to an object, a circuit for generating a measurement signal according to at least a strain amount of the object by the strain gauge, and converting the measurement signal into digital data A / D conversion means and data output processing means for outputting digital data of the measurement signal or digital data generated through predetermined processing from the digital data to the outside as measurement output data. A strain measurement module, comprising: a module main body formed as a module; and connecting the module main body to the strain gauge in the vicinity thereof. 2. The strain measuring module according to claim 1, wherein the strain gauge covered with a protective coating member is integrally mounted on the module main body. 3. The strain gauge covered with a protective coating member is detachably mounted on the module main body together with the coating member, and the strain gauge is electrically connected to the module main body in the mounted state. The strain measuring module according to claim 1, wherein a connecting portion to be provided is provided on an outer surface of the coating member. 4. The module according to claim 1, wherein said strain gauge is detachably connected to said module body.
The described strain measurement module. 5. An apparatus according to claim 1, further comprising a temperature sensor for detecting a temperature of said object, said A / D conversion means including means for converting a detection signal of said temperature sensor into digital data, and said data output processing means comprising: The strain measurement module according to claim 1, further comprising a unit that externally outputs digital data of a detection signal of the sensor. 6. A temperature sensor for detecting a temperature of the object, wherein the A / D conversion means includes means for converting a detection signal of the temperature sensor into digital data, and wherein the data output processing means includes: The strain measurement module according to claim 1, further comprising a unit configured to correct and output the measurement output data based on the temperature of the object indicated by digital data of a detection signal of a sensor. 7. The strain gauge is a rosette gauge comprising at least three strain gauges, and the measurement signal generation circuit includes means for generating the measurement signal for each strain gauge of the rosette gauge. The data output processing means, from digital data of the measurement signal for each strain gauge, at least one of the principal strain amount of the object, the shear strain amount, and the direction of the principal strain, rosette analysis as the measurement output data The strain measurement module according to claim 1, further comprising a unit that obtains the strain by processing. 8. A strain gauge is attached to each of a plurality of objects or a plurality of parts of an object, and the strain gauge generates a measurement signal corresponding to a strain amount of each object or each part of the object. In a system that performs multi-point strain measurement for a plurality of objects or a plurality of parts of the object based on, a measurement signal generation circuit for generating the measurement signal by at least a strain gauge attached to each object or each part of the object, A for converting the measurement signal into digital data
/ D conversion means, digital data of the measurement signal, or
A data output processing means for outputting digital data generated through predetermined processing from the digital data to the outside as measurement output data; and a module main unit integrally formed as a module. A plurality of strain measurement modules connected to strain gauges of each object or each part of the object in the vicinity thereof, and the measurement output data output from the data output processing means of each strain measurement module are collected and processed. A multi-point strain measurement system characterized by comprising a data output processing means of each strain measurement module and a measurement data processing device communicably provided. 9. The data output processing means of each of the strain measurement modules, by selectively giving an output operation command specific to the strain measurement module from the measurement data processing device to the data output processing means, The multipoint strain measurement system according to claim 8, wherein output data is output to the measurement data processing device. 10. The multi-point strain measurement according to claim 9, wherein said measurement data processing device and data output processing means of each strain measurement module are communicably connected via a common communication line. system. 11. The measurement data processing device includes means for supplying power to each of the strain measurement modules via the common communication line, and supplies the power to the module body of each of the strain measurement modules from the common communication line. The multi-point strain measurement system according to claim 10, further comprising a power supply unit for extracting power supply power of the strain measurement module. 12. The data output processing means of each of the strain measurement modules includes storage means for storing and holding the measurement output data, and responds to a measurement start command common to each of the strain measurement modules given from the measurement data processing device. The measurement output data based on the output of the A / D conversion means when the measurement start command is given is stored and held in the storage means, and the stored measurement output data is stored in accordance with the output operation command. The multipoint strain measurement system according to claim 9, wherein the system outputs the data to a data processing device.