Stress-strain sensor with secondary temperature self-adaption function and application thereof

Abstract

The invention relates to the technical field of stress-strain measurement, and discloses a stress-strain sensor with a secondary temperature self-adaption function and application of the stress-strain sensor. The temperature coefficient of a temperature sensitive unit included in the stress-strain sensor is the same as that of the measured structure, when the measured structure is deformed due to the temperature influence, the deformation quantity of the temperature sensitive unit is consistent with that of the measured structure, and at the moment, stress-strain data output by the measuring sheet is a stress-strain analog signal after one-time temperature self-adaption; the stress-strain sensor further comprises a data acquisition chip and a data processing chip, and a temperature sensor is arranged in the data acquisition chip and used for acquiring the stress-strain value corresponding to each working condition temperature. A correction model is configured in the data processing chip, the data processing chip receives the stress-strain analog signal subjected to primary temperature self-adaption, and after the stress-strain analog signal is corrected by the correction model, a stress-strain digital signal subjected to secondary temperature self-adaption is obtained. The device is simple in structure, low in cost and capable of accurately filtering deformation quantity caused by temperature.

Description

Technical Field

[0001] The present invention relates to the technical field of stress and strain measurement, and in particular to a stress and strain sensor with a secondary temperature self-adaptation function and application thereof. Background Art

[0002] The measured structure will be deformed due to the influence of temperature. In the long-term measurement of stress and strain of the measured structure, the deformation caused by temperature can reach the same order of magnitude as the deformation caused by force. In practical applications, stress and strain sensors are usually used to measure the deformation of the measured structure. The installation method of traditional stress and strain sensors is generally to connect the two ends of the stress and strain sensor measurement direction with the surface of the measured structure with two column feet within a suitable distance, and use this method to form a frame structure to measure the stress and strain value of the measured structure. However, for general stress and strain sensors, if the surface of the structure is deformed, the sensor will have an output, and it is impossible to distinguish whether the deformation is caused by force or temperature. This type of sensor is not suitable for use in long-term measurements.

[0003] In order to compensate for the deformation of the measured structure caused by temperature, there are also some sensors specifically used to compensate for the influence of the surface temperature of the measured structure. Most of the compensation methods use a temperature compensation metal block with the same temperature coefficient and paste a strain gauge on it for temperature compensation. The strain gauge used to measure the signal is called a measuring piece, and the strain gauge used for temperature compensation is called a compensation piece. Then the signal on the sensor measuring piece minus the signal on the compensation piece can theoretically eliminate the influence of temperature. There is also a differential measurement method to form a full-bridge measurement. The positive output is used as a measuring piece, and the negative output is used as both a measuring piece and a compensation piece. Whether the surface of the measured structure is deformed by stress or by temperature, the positive output measuring piece has a signal output. It cannot distinguish the deformation caused by temperature. It can only compensate for the influence of temperature on the positive output measuring piece when the negative output measuring piece is used as a compensation piece. In short, the existing method cannot distinguish whether the deformation of the surface of the measured structure is caused by stress or by temperature by the measuring piece itself, and the compensation piece is required to compensate for the influence of temperature. This will undoubtedly lead to the complication of the measurement process and the increase of measurement costs.

[0004] In addition, in practical applications, the temperature coefficient of the measured structure has a range. For example, the linear expansion coefficient of A3 steel is 10-13με / ℃. The linear expansion coefficients of different positions of large steel structures are not necessarily the same. For the temperature coefficient of the metal compensation block, it is impossible to be very close to the temperature coefficient of different positions of the steel structure, which brings about the error of temperature compensation. If this error exceeds the error range of the system, it will affect the measurement results. Moreover, in practical applications, the installation position of each sensor is not the same. It is difficult for traditional sensors to automatically measure the temperature coefficient of the current position, which will undoubtedly affect the accuracy of temperature measurement.

[0005] Therefore, it is urgent to propose a stress-strain sensor with simple process and temperature adaptive function. Summary of the invention

[0006] The purpose of the present invention is to provide a stress-strain sensor with a secondary temperature adaptation function and its application. The first temperature adaptation is to achieve the distinction between deformation caused by stress and deformation caused by temperature by relying on a measuring piece through the internal structure design of the sensor, without the need for a compensation piece or other temperature compensation device; the second temperature adaptation is to design a correction model to correct the stress-strain simulation signal after the first temperature adaptation.

[0007] In order to achieve the above object, the present invention adopts the following technical scheme:

[0008] In a first aspect, the present invention provides a stress-strain sensor with a secondary temperature self-adaptation function. When in use, the stress-strain sensor is installed on a measured structure. When the measured structure is deformed by force, a measuring piece included in the stress-strain sensor outputs a stress-strain analog signal.

[0009] The temperature coefficient of the temperature sensitive unit included in the stress and strain sensor is the same as the temperature coefficient of the measured structure. The projection of the temperature sensitive unit on the measured structure is located between the central axes of the two installation positions of the stress and strain sensor. When the measured structure is deformed due to temperature changes, the deformation amount of the temperature sensitive unit is consistent with the deformation amount of the measured structure, and the measuring piece does not output a stress and strain simulation signal, that is, the stress and strain data output by the measuring piece is a stress and strain simulation signal after one temperature adaptation;

[0010] The stress-strain sensor also includes a data acquisition chip, which has a built-in temperature sensor; the temperature sensor acquires stress-strain values ​​corresponding to each ambient temperature, that is, a constant combination is formed by multiple ambient temperatures and the stress-strain values ​​corresponding thereto; the data acquisition chip is also used to acquire the stress-strain analog signal output by the measuring piece after a temperature adaptation, and convert the stress-strain analog signal after a temperature adaptation into a stress-strain digital signal after a temperature adaptation;

[0011] The stress-strain sensor also includes a data processing chip, which is equipped with a correction model. The correction model is a difference function between the stress-strain digital signal after the first temperature adaptation and the stress-strain error. The stress-strain error is the product of a constant combination and an independent variable temperature function. The data processing chip receives the stress-strain analog signal after the first temperature adaptation, and after being corrected by the correction model, obtains the stress-strain digital signal after the second temperature adaptation.

[0012] As a possible implementation, the measuring piece includes a first sensitive grid and a second sensitive grid that are symmetrically and spaced apart; when the measured structure does not deform, the length extension direction of the first sensitive grid and the second sensitive grid is perpendicular to the central axis of the measured structure; when the measured structure is deformed by force, the first sensitive grid is stretched to output a positive strain, and the second sensitive grid is compressed to output a negative strain;

[0013] The first sensitive gate and the second sensitive gate are connected to form a first half bridge, and the connection point is connected to a first input pin (11) of a data acquisition chip;

[0014] It also includes a first resistor and a second resistor connected in series to form a second half bridge, the connection point of which is connected to a second input pin (10) of a data acquisition chip; the first sensitive gate and the other end of the first resistor are connected to the positive electrode of the bridge supply voltage; the second sensitive gate and the other end of the second resistor are connected to the negative electrode of the bridge supply voltage and are grounded through a ground pin of the data acquisition chip; the first half bridge and the second half bridge form a full bridge circuit, and the data acquisition chip converts the stress strain analog signal output by the full bridge after a temperature self-adaptation into a stress strain digital signal after a temperature self-adaptation.

[0015] As a possible implementation method, the modified model is:

[0016] e=e1-e t

[0017] Among them, e is the stress-strain simulation signal after secondary temperature adaptation, e1 is the stress-strain simulation signal after primary temperature adaptation, and e t is the stress-strain error, e t =kf(t), k is a constant combination, and f(t) is a function of the independent variable temperature.

[0018] As a possible implementation method, the stress strain sensor also includes:

[0019] The spindle assembly is mounted on the structure to be measured in such a way that its central axis is perpendicular to the central axis of the structure to be measured;

[0020] The secondary shaft assembly has a height difference greater than 0 with the main shaft assembly and is installed on the structure to be measured along the measured direction, and the central axis of the secondary shaft assembly is perpendicular to the central axis of the structure to be measured;

[0021] The positioning member defines a relatively high main shaft assembly or a secondary shaft assembly as a positioning shaft assembly; the positioning member is installed at one end of the positioning shaft assembly away from the structure to be measured; one side of the positioning member protrudes from the side opposite to the main shaft assembly and the secondary shaft assembly;

[0022] A cantilever, the cantilever is installed on a side of the positioning member opposite to the secondary shaft assembly, and the central axis of the cantilever is perpendicular to the central axis of the structure to be measured; measuring pieces are symmetrically installed on both sides of one end of the cantilever close to the positioning member;

[0023] A pull rod, one end of which is connected to the top end of the secondary shaft assembly, and the other end of which is connected to the suspended end of the cantilever; the central axis of the pull rod is parallel to the central axis of the structure to be measured;

[0024] The main shaft assembly, the positioning member, the drawbar and the secondary shaft assembly form a temperature sensitive unit.

[0025] As a possible implementation, the main shaft assembly includes a main shaft base and a coaxially connected main shaft, and the connection is coplanar; the secondary shaft assembly includes a secondary shaft base and a coaxially connected secondary shaft, and the connection is coplanar.

[0026] As a possible implementation method, the secondary shaft is lower than the main shaft; the lower end plane of the positioning member is coplanar with the upper end plane of the main shaft at the connection; the vertical surface of the positioning member opposite to the secondary shaft has a groove, and the bottom surface of the groove is parallel to the central axis of the main shaft; the vertical surface of the upper end of the cantilever opposite to the main shaft is tightly connected with the bottom surface of the groove to avoid cantilever twisting.

[0027] As a possible implementation manner, the main shaft base and the secondary shaft base are of the same height, and the bottom planes of the main shaft base and the secondary shaft base are coplanar, and the top planes of the main shaft base and the secondary shaft base are coplanar.

[0028] As a possible implementation, the stress-strain sensor further includes a communication interface chip connected to the data processing chip, and exchanges data with the terminal device via the communication interface chip.

[0029] In a second aspect, the present invention provides an application of a stress-strain sensor with a secondary temperature adaptive function, wherein the stress-strain sensor is installed on a measured structure, a large-scale equipment or a large-scale bridge to monitor the deformation caused by the stress.

[0030] In a third aspect, the present invention further provides an application method of a stress strain sensor with a secondary temperature adaptive function, wherein the stress strain sensor is the stress strain sensor provided in the first aspect; the application method comprises the following steps:

[0031] S10. Install the stress and strain sensor on the surface of the measured structure along the measuring direction;

[0032] S11. Preset a temperature change cycle, apply the temperature sensor built into the data acquisition chip to obtain a constant combination, and write it into the data processing chip to complete the configuration of the correction model;

[0033] S12. When the measured structure is deformed by stress, the pull rod drives the bottom end of the boom to move, further stretching the first sensitive grid and compressing the second sensitive grid, and the data acquisition chip obtains the stress-strain analog signals output by the first sensitive grid and the second sensitive grid; while the measured structure is deformed by stress, it is also deformed by the ambient temperature, and the deformation caused by temperature change is consistent with the deformation of the temperature sensitive unit, so that the first sensitive grid and the second sensitive grid do not deform, that is, the deformation caused by temperature change is not output through the first sensitive grid and the second sensitive grid;

[0034] S13. The data acquisition chip receives the stress-strain analog signal after a temperature adaptation and converts it into a stress-strain digital signal after a temperature adaptation;

[0035] S14. The data processing chip receives the stress-strain digital signal after the first temperature self-adaptation, and obtains the stress-strain digital signal after the second temperature self-adaptation after correction by the correction model.

[0036] Compared with the prior art, the beneficial effects of the present invention are:

[0037] 1. The stress-strain sensor provided by the present invention has a secondary temperature adaptation function. The first temperature adaptation is realized through the internal structure of the stress-strain sensor, and the second temperature adaptation is realized through the correction model configured in the data processing chip included in the stress-strain sensor. When measuring the deformation of the measured structure, the deformation caused by temperature can be accurately filtered out through two temperature adaptations, thereby obtaining a more accurate measurement result of the deformation caused by the force.

[0038] 2. The stress-strain sensor provided by the present invention collects the influence of temperature at different positions of the measured structure on stress and strain to form a constant combination, determines the stress-strain error based on the constant combination and the independent variable temperature function, and uses the difference function between the stress-strain digital signal after one temperature adaptation and the stress-strain error as a correction model. The calculation accuracy is high, and the deformation variable caused by temperature can be accurately distinguished from the deformation variable caused by force.

[0039] 3. The stress-strain sensor provided by the present invention can distinguish deformation caused by temperature from deformation affected by force by only relying on a measuring sheet, without requiring a compensation sheet or other temperature compensation devices, and has the advantages of simple process and low cost.

[0040] 4. The stress-strain sensor provided by the present invention is widely applicable to long-term monitoring of large equipment or large bridges, and can eliminate the influence of temperature on the deformation amount and obtain accurate deformation amount caused by force. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0042] Figure 1 This is a schematic diagram of a stress and strain sensor installed on a measured structure in an embodiment of the present invention;

[0043] Figure 2 This is a schematic diagram of the structure of a stress and strain sensor in an embodiment of the present invention;

[0044] Figure 3 This is a circuit diagram of digital signal transmission between a data acquisition chip, a data processing chip and a communication interface chip in an embodiment of the present invention.

[0045] Reference numerals

[0046] 1-stress and strain sensor, 10-measuring piece, 100-first sensitive grid, 101-second sensitive grid, 11-spindle assembly, 110-spindle base, 111-spindle, 12-secondary shaft assembly, 120-secondary shaft base, 121-secondary shaft, 13-positioning piece, 14-cantilever, 15-pull rod, 16-data acquisition chip, 160-temperature sensor, 17-data processing chip, 18-communication interface chip, 2-measured structure. DETAILED DESCRIPTION

[0047] In order to clearly describe the technical solutions of the embodiments of the present invention, in the embodiments of the present invention, words such as "first" and "second" are used to distinguish the same items or similar items with basically the same functions and effects. For example, the first threshold and the second threshold are only used to distinguish different thresholds, and their order is not limited. Those skilled in the art can understand that words such as "first" and "second" do not limit the quantity and execution order, and words such as "first" and "second" do not necessarily limit them to be different.

[0048] It should be noted that, in the present invention, words such as "exemplary" or "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "exemplary" or "for example" in the present invention should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a specific way.

[0049] In the present invention, "at least one" means one or more, and "plurality" means two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone, where A and B can be singular or plural. The character " / " generally indicates that the associated objects before and after are in an "or" relationship. The following at least one item (items) or similar expressions thereof refer to any combination of these items, including any combination of single items (items) or plural items (items). For example, at least one item (items) of a, b or c can mean: a, b, c, the combination of a and b, the combination of a and c, the combination of b and c, or the combination of a, b and c, where a, b, c can be single or multiple.

[0050] The embodiment of the present invention provides a stress strain sensor with a secondary temperature self-adaptation function and its application, wherein the first temperature self-adaptation is realized by the internal structure of the stress strain sensor, and the second temperature self-adaptation is realized by a correction model configured in a data processing chip included in the stress strain sensor. The present invention is further described below in conjunction with the accompanying drawings.

[0051] In a first aspect, an embodiment of the present invention provides a stress strain sensor with a secondary temperature adaptive function, see Figure 1 In the use state, the stress and strain sensor 1 is installed on the measured structure 2; when the measured structure 2 is deformed by force, the measuring piece 10 included in the stress and strain sensor 1 outputs a stress and strain analog signal;

[0052] See also Figure 2 As a possible implementation, the measuring piece 10 includes a first sensitive grid 100 and a second sensitive grid 101 which are symmetrically and spaced apart; when the measured structure 2 is not deformed, the length extension direction of the first sensitive grid 100 and the second sensitive grid 101 is perpendicular to the central axis of the measured structure 2; when the measured structure 2 is deformed by force, the first sensitive grid 100 is stretched to output a positive strain, and the second sensitive grid 101 is compressed to output a negative strain, or the first sensitive grid 100 is compressed to output a negative strain, and the second sensitive grid 101 is stretched to output a positive strain.

[0053] See also Figure 2 As a possible implementation, the stress strain sensor 1 further includes:

[0054] The spindle assembly 11 is installed on the structure 2 to be measured in such a way that its central axis is perpendicular to the central axis of the structure 2 to be measured;

[0055] The secondary shaft assembly 12 has a height difference greater than 0 with the main shaft assembly 11 and is installed on the measured structure 2 along the measured direction, and the central axis of the secondary shaft assembly 12 is perpendicular to the central axis of the measured structure 2;

[0056] The positioning member 13 defines the relatively higher main shaft assembly 11 or the secondary shaft assembly 12 as a positioning shaft assembly; the positioning member 13 is installed at one end of the positioning shaft assembly away from the measured structure 2; one side of the positioning member 13 protrudes from the side opposite to the main shaft assembly 11 and the secondary shaft assembly 12;

[0057] The cantilever 14 is installed on a side of the positioning member 13 opposite to the secondary shaft assembly 12, and the central axis of the cantilever 14 is perpendicular to the central axis of the measured structure 2; the measuring pieces 10 are symmetrically installed on both sides of one end of the cantilever 14 close to the positioning member 13; illustratively, the measuring pieces 10 are adhered to both sides of the cantilever 14 using high-temperature curing adhesive.

[0058] A pull rod 15, one end of which is connected to the top end of the secondary shaft assembly 12, and the other end of which is connected to the suspended end of the cantilever 14; the central axis of the pull rod 15 is parallel to the central axis of the measured structure 2; illustratively, the pull rod 15 and the secondary shaft assembly 12 are connected by threads, and the pull rod 15 and the cantilever 14 can be processed as one piece, or can be connected by screws.

[0059] The main shaft assembly 11 , the positioning member 13 , the pull rod 15 and the secondary shaft assembly 12 constitute a temperature sensitive unit.

[0060] See also Figure 2 As a possible implementation, the main shaft assembly 11 includes a main shaft base 110 and a coaxially connected main shaft 111, the connection is coplanar, ensuring that the bottom plane of the main shaft base 110 is perpendicular to the central axis of the main shaft 111; the secondary shaft assembly 12 includes a secondary shaft base 120 and a coaxially connected secondary shaft 121, the connection is coplanar, ensuring that the bottom plane of the secondary shaft base 120 is perpendicular to the central axis of the secondary shaft 121. Exemplarily, the main shaft base 110 and the main shaft 111, and the secondary shaft base 120 and the secondary shaft 121 are both threadedly connected.

[0061] See also Figure 2 As a possible implementation, the secondary shaft 121 is lower than the primary shaft 111; the lower end plane of the positioning member 13 is coplanar with the upper end plane of the primary shaft 111; the vertical surface of the positioning member 13 opposite to the secondary shaft 121 has a groove, and the bottom surface of the groove is parallel to the central axis of the primary shaft 111; the vertical surface of the upper end of the cantilever 14 opposite to the primary shaft 111 is tightly connected to the bottom surface of the groove to prevent the cantilever 14 from twisting. Exemplarily, the lower end plane of the positioning member 13 is connected to the upper end plane of the primary shaft 111 by threaded connection, and the vertical surface of the upper end of the cantilever 14 opposite to the primary shaft 111 is connected to the bottom surface of the groove by screws.

[0062] See also Figure 2As a possible implementation method, the main shaft base 110 and the secondary shaft base 120 are of the same height, and the bottom planes of the main shaft base 110 and the secondary shaft base 120 are coplanar, and the top planes of the main shaft base 110 and the secondary shaft base 120 are coplanar; illustratively, the pull rod 15 and the secondary shaft assembly 12 are connected by threads, and the bottom planes of the main shaft base 110 and the secondary shaft base 120 can be made coplanar by adjusting the screw-in distance.

[0063] See also Figure 2 As an example, after the parts included in the stress and strain sensor are connected, they are reinforced with anti-loosening glue to ensure the firmness and stability of the stress and strain sensor. In this embodiment, the connection method between the main shaft base 110, the secondary shaft base 120 and the measured structure 2 is not specifically limited, and welding, gluing, permanent magnetic attraction and the like can be used. During installation and transportation, in order to prevent the relative movement between the main shaft base 110 and the secondary shaft base 120, a special clamp can be used to fix the two, and the clamp can be removed after the installation and transportation is completed; in order to increase the protection level, a shell can also be installed on the main shaft base 110 and the secondary shaft base 120 for protection, as long as it does not affect the relative displacement of the two.

[0064] See also Figure 2 As an example, the main shaft 111, the main shaft base 110, the positioning member 13, the cantilever 14, the pull rod 15, the secondary shaft base 120 and the secondary shaft 121 can be processed by CNC machine tools, and the size of each part follows the following principle: when the stress strain sensor is subjected to force along the center line connecting the main shaft base 110 and the secondary shaft base 120, the total deformation of the parts except the cantilever 14 can be controlled within the allowable measurement error range compared with the deformation of the cantilever 14.

[0065] The temperature coefficient of the temperature sensitive unit included in the stress and strain sensor is the same as the temperature coefficient of the measured structure. The projection of the temperature sensitive unit on the measured structure is located between the central axes of the two installation positions of the stress and strain sensor. When the measured structure is deformed due to temperature changes, the deformation amount of the temperature sensitive unit is consistent with the deformation amount of the measured structure, and the measuring piece does not output a stress and strain simulation signal, that is, the stress and strain simulation signal output by the measuring piece is a stress and strain simulation signal after one temperature adaptation.

[0066] The stress-strain sensor also includes a data acquisition chip 16, which has a built-in temperature sensor 160; illustratively, the data acquisition chip is welded on a circuit board, and the circuit board is installed in the housing of the stress-strain sensor. The temperature sensor 160 collects the stress-strain value corresponding to each ambient temperature, that is, a constant combination is formed by multiple ambient temperatures and the stress-strain values ​​corresponding thereto; it should be explained that since there is no heat source inside the measured structure, the temperature of the measured structure and the surrounding environment are the same, and the temperature sensor 160 collects the ambient temperature, which is equivalent to collecting the temperature of the measured structure. The data acquisition chip 16 is also used to collect the stress-strain analog signal output by the measuring piece 10 after a temperature adaptation, and convert the stress-strain analog signal after a temperature adaptation into a stress-strain digital signal after a temperature adaptation.

[0067] Combine the following Figure 2 The principle of realizing the first temperature self-adaptation of the present invention is specifically described. The main shaft base 110 and the secondary shaft base 120 of the stress and strain sensor of this embodiment are respectively fixed on two points extending along the measured direction on the surface of the measured structure 2. When the measured structure 2 is deformed due to force, a relative displacement occurs between the main shaft 111 and the secondary shaft 121. At this time, the secondary shaft 121 drives the pull rod 15, and the pull rod 15 drives the lower end of the cantilever 14 to move, so that the cantilever 14 is bent, and one of the first sensitive grid 100 and the second sensitive grid 101 is stretched and outputs a positive strain, and the other is compressed and outputs a negative strain; the difference between the positive strain and the negative strain is twice the strain of the measured structure 2 due to force, and the strain caused by force can be measured by the data acquisition chip 16; when the measured structure 2 is deformed due to temperature, since the temperature coefficient of the temperature sensitive unit is the same as the temperature coefficient of the measured structure 2, that is, the two have the same expansion or contraction trend under the same environment. Therefore, when the measured structure 2 is deformed by the influence of temperature, the temperature sensitive unit and the measured structure 2 have the same displacement change, that is, the relative position of the two does not change, so the first sensitive grid 100 and the second sensitive grid 101 do not deform, and no strain amount is output. The present invention can distinguish the deformation caused by temperature from the deformation affected by force only by the temperature sensitive unit and the measuring sheet, without the need for a compensation sheet or other temperature compensation device, and has the advantages of simple process and low cost.

[0068] See also Figures 2 to 3As a possible implementation, the first sensitive gate 100 and the second sensitive gate 101 are connected to form a first half bridge, and the connection point is connected to the first input pin (11) of the data acquisition chip 16; and also includes a first resistor R6 and a second resistor R7 connected in series to form a second half bridge, and the connection point is connected to the second input pin (10) of the data acquisition chip 16; the other end of the first sensitive gate 100 and the first resistor R6 is connected to the positive electrode of the bridge supply voltage; the other end of the second sensitive gate 101 and the second resistor R7 is connected to the negative electrode of the bridge supply voltage, and is grounded through the ground pin of the data acquisition chip 16; for example, see Figure 3 The positive pole of the bridge voltage is the +3V voltage connected to the pins (15), (20), and (21) of the data acquisition chip 16, and the negative pole of the bridge voltage is the pins (16) and (17) of the data acquisition chip 16. The first half bridge and the second half bridge form a full bridge circuit. When a voltage is applied to the full bridge circuit, a differential voltage is obtained on the pins (10) and (11) of the data acquisition chip 16. The differential voltage is calibrated to be a stress-strain analog signal after a temperature adaptation. The data acquisition chip 16 converts the stress-strain analog signal after a temperature adaptation output by the full bridge circuit into a stress-strain digital signal after a temperature adaptation.

[0069] See also Figure 3 The stress-strain sensor also includes a data processing chip 17, in which a correction model is configured. The correction model is a difference function between the stress-strain digital signal after a temperature adaptation and the stress-strain error, and the stress-strain error is the product of a constant combination and an independent variable temperature function; illustratively, the constant combination includes multiple constants, such as a proportional constant, an integral constant, a differential constant, etc. The constant combination is obtained in the following manner: the stress-strain sensor is installed at different positions of the measured structure, and a temperature cycle of 24 hours is experienced, and the influence of the temperature at different positions on the stress-strain is collected to form a constant combination.

[0070] The data processing chip 17 receives the stress-strain analog signal after the primary temperature adaptation, and obtains the stress-strain digital signal after the secondary temperature adaptation after correction by the correction model. Exemplarily, the data acquisition chip 16 writes the constant combination into the data processing chip 17 for permanent memory to complete the configuration of the correction model.

[0071] As a possible implementation method, the modified model is:

[0072] e=e1-e t

[0073] Among them, e is the stress-strain simulation signal after secondary temperature adaptation, e1 is the stress-strain simulation signal after primary temperature adaptation, and e tis the stress-strain error, e t =kf(t), k is a constant combination, f(t) is a function of the independent variable temperature, and t is temperature.

[0074] The stress-strain sensor provided in this embodiment collects the influence of temperature at different positions of the measured structure on stress and strain to form a constant combination, determines the stress-strain error based on the constant combination and the independent variable temperature function, and uses the difference function between the stress-strain digital signal after one temperature adaptation and the stress-strain error as a correction model. The calculation accuracy is high, and the deformation variable caused by temperature can be accurately distinguished from the deformation variable caused by force.

[0075] See also Figure 3 As a possible implementation, the stress strain sensor further includes a communication interface chip 18 connected to the data processing chip 17 , and exchanges data with the terminal device through the communication interface chip 18 .

[0076] Combine the following Figure 3 The principle of realizing the second temperature adaptation of the present invention is specifically described. The data acquisition chip 16 converts the stress-strain analog signal after the first temperature adaptation output by the full-bridge circuit into a stress-strain digital signal after the first temperature adaptation. The output pin (3), output pin (23), and output pin (24) of the data acquisition chip 16 are respectively connected to the input pin (3), input pin (31), and input pin (5) of the data processing chip 17, so as to send the stress-strain analog signal after the first temperature adaptation to the data processing chip 17. After the correction model in the data processing chip 17 corrects the stress-strain analog signal after the first temperature adaptation, a stress-strain digital signal after the second temperature adaptation is obtained. The output pin (21), output pin (22), and output pin (25) of the data processing chip 17 are respectively connected to the input pin (4), input pin (1), input pin (2), and (3) of the communication interface chip 18, so as to realize data exchange with the terminal device through the communication interface chip 18, that is, to realize filtering out the deformation caused by temperature and only outputting the deformation caused by force.

[0077] In a second aspect, the present invention provides an application of a stress-strain sensor with a secondary temperature adaptive function, wherein the stress-strain sensor is installed on a measured structure, a large-scale equipment or a large-scale bridge to monitor the deformation caused by the stress.

[0078] In a third aspect, the present invention provides an application method of a stress strain sensor with a secondary temperature self-adaptation function, wherein the stress strain sensor is the stress strain sensor provided in the first aspect; the application method comprises the following steps:

[0079] S10. Install the stress and strain sensor on the surface of the structure to be measured along the measuring direction; illustratively, the data acquisition chip and data processing chip included in the stress and strain sensor are both welded on the circuit board, the circuit board and other structural components of the stress and strain sensor are installed in a housing, the measuring piece is connected to the corresponding position of the circuit board through a wire, and after assembling and debugging the circuit, a complete stress and strain sensor is formed. When in use, the main shaft base and the secondary shaft base of the stress and strain sensor are bonded to the surface of the structure to be measured to measure stress and strain;

[0080] S11. Preset a temperature change cycle, apply the temperature sensor built into the data acquisition chip to obtain a constant combination, and write it into the data processing chip to complete the configuration of the correction model;

[0081] S12. When the measured structure is deformed by stress, the pull rod drives the bottom end of the boom to move, further stretching the first sensitive grid and compressing the second sensitive grid, and the data acquisition chip obtains the stress-strain analog signals output by the first sensitive grid and the second sensitive grid; while the measured structure is deformed by stress, it is also deformed by the ambient temperature, and the deformation caused by temperature change is consistent with the deformation of the temperature sensitive unit, so that the first sensitive grid and the second sensitive grid do not deform, that is, the deformation caused by temperature change is not output through the first sensitive grid and the second sensitive grid;

[0082] S13. The data acquisition chip receives the stress-strain analog signal after a temperature adaptation and converts it into a stress-strain digital signal after a temperature adaptation;

[0083] S14. The data processing chip receives the stress-strain digital signal after the first temperature self-adaptation, and obtains the stress-strain digital signal after the second temperature self-adaptation after correction by the correction model.

[0084] The present invention uses the secondary temperature adaptation function of the stress strain sensor to accurately filter out the deformation caused by temperature when measuring the deformation of the measured structure through two temperature adaptations, thereby obtaining a more accurate measurement result of the deformation caused by the force.

[0085] Although the present invention is described herein in conjunction with various embodiments, in the process of implementing the claimed invention, those skilled in the art may understand and implement other variations of the disclosed embodiments by viewing the drawings, the disclosure, and the drawings, etc. In the specification, the word "comprising" does not exclude other components or steps, and "one" or "an" does not exclude multiple situations. A single processor or other unit can implement several functions listed in the specification. Certain measures are recorded in different embodiments, but this does not mean that these measures cannot be combined to produce good results.

[0086] Although the present invention has been described in conjunction with specific features and embodiments thereof, it is apparent that various modifications and combinations may be made thereto without departing from the spirit and scope of the present invention. Accordingly, this specification and the accompanying drawings are merely exemplary illustrations of the present invention and are deemed to cover any and all modifications, variations, combinations or equivalents within the scope of the present invention. Obviously, those skilled in the art may make various modifications and variations to the present invention without departing from the spirit and scope of the present invention. Thus, the present invention is intended to include such modifications and variations if they fall within the scope of the present invention and its equivalents.

Claims

1. A stress strain sensor with secondary temperature adaptive function, characterized in that: In the use state, the stress and strain sensor is installed on the measured structure; when the measured structure is deformed by force, the measuring piece included in the stress and strain sensor outputs a stress and strain analog signal; The temperature coefficient of the temperature sensitive unit included in the stress and strain sensor is the same as the temperature coefficient of the measured structure. The projection of the temperature sensitive unit on the measured structure is located between the central axes of the two installation positions of the stress and strain sensor. When the measured structure is deformed due to temperature changes, the deformation amount of the temperature sensitive unit is consistent with the deformation amount of the measured structure, and the measuring piece does not output a stress and strain simulation signal, that is, the stress and strain simulation signal output by the measuring piece is a stress and strain simulation signal after one temperature adaptation; The stress-strain sensor further comprises a data acquisition chip, wherein the data acquisition chip has a built-in temperature sensor; the temperature sensor acquires stress-strain values ​​corresponding to each ambient temperature, i.e., a constant combination is formed by multiple ambient temperatures and the stress-strain values ​​corresponding thereto; the data acquisition chip is also used to acquire the stress-strain analog signal output by the measuring piece after a temperature adaptation, and convert the stress-strain analog signal after a temperature adaptation into a stress-strain digital signal after a temperature adaptation; The stress-strain sensor also includes a data processing chip, in which a correction model is configured. The correction model is a difference function between the stress-strain digital signal after a primary temperature adaptation and the stress-strain error, and the stress-strain error is the product of a constant combination and an independent variable temperature function. The data processing chip receives the stress-strain analog signal after a primary temperature adaptation, and after correction by the correction model, obtains the stress-strain digital signal after a secondary temperature adaptation.

2. The stress-strain sensor with secondary temperature self-adaptation function according to claim 1, characterized in that: The measuring piece comprises a first sensitive grid and a second sensitive grid which are symmetrically and spaced apart; when the measured structure does not deform, the length extension direction of the first sensitive grid and the second sensitive grid is perpendicular to the central axis of the measured structure; When the measured structure is deformed by force, the first sensitive grid is stretched to output a positive strain, and the second sensitive grid is compressed to output a negative strain; The first sensitive gate and the second sensitive gate are connected to form a first half bridge, and the connection point is connected to a first input pin (11) of a data acquisition chip; It also includes a first resistor and a second resistor connected in series to form a second half bridge, the connection point of which is connected to a second input pin (10) of a data acquisition chip; the first sensitive gate and the other end of the first resistor are connected to the positive electrode of the bridge supply voltage; the second sensitive gate and the other end of the second resistor are connected to the negative electrode of the bridge supply voltage and are grounded through a ground pin of the data acquisition chip; the first half bridge and the second half bridge form a full bridge circuit, and the data acquisition chip converts the stress and strain analog signal output by the full bridge after a temperature self-adaptation into a stress and strain digital signal after a temperature self-adaptation.

3. The stress-strain sensor with secondary temperature self-adaptation function according to claim 2, characterized in that: The modified model is: e=e1-e t Among them, e is the stress-strain digital signal after secondary temperature adaptation, e1 is the stress-strain digital signal after primary temperature adaptation, and e t is the stress-strain error, e t =kf(t), k is a constant combination, f(t) is a function of the independent variable temperature, and t is temperature.

4. The stress-strain sensor with secondary temperature self-adaptation function according to claim 1, characterized in that: The stress strain sensor also includes: The spindle assembly is mounted on the structure to be measured in such a way that its central axis is perpendicular to the central axis of the structure to be measured; A secondary shaft assembly, having a height difference greater than 0 with the main shaft assembly, is installed on the structure to be measured along the measured direction, and the central axis of the secondary shaft assembly is perpendicular to the central axis of the structure to be measured; A positioning member defines a relatively high main shaft assembly or a secondary shaft assembly as a positioning shaft assembly; the positioning member is installed at one end of the positioning shaft assembly away from the structure to be measured; one side of the positioning member protrudes from the side of the main shaft assembly opposite to the secondary shaft assembly; A cantilever, the cantilever being mounted on a side of the positioning member opposite to the secondary shaft assembly, the central axis of the cantilever being perpendicular to the central axis of the structure to be measured; measuring pieces are symmetrically mounted on both sides of one end of the cantilever close to the positioning member; A pull rod, one end of which is connected to the top end of the secondary shaft assembly, and the other end of which is connected to the suspended end of the cantilever; the central axis of the pull rod is parallel to the central axis of the structure to be measured; The main shaft assembly, the positioning member, the pull rod and the secondary shaft assembly constitute a temperature sensitive unit.

5. The stress-strain sensor with secondary temperature self-adaptation function according to claim 4, characterized in that: The main shaft assembly comprises a main shaft base and a coaxially connected main shaft, and the connection is coplanar; the secondary shaft assembly comprises a secondary shaft base and a coaxially connected secondary shaft, and the connection is coplanar.

6. The stress-strain sensor with secondary temperature self-adaptation function according to claim 5, characterized in that: The secondary shaft is lower than the primary shaft; the lower end plane of the positioning member is coplanar with the upper end plane of the primary shaft at the connection; the vertical surface of the positioning member opposite to the secondary shaft has a groove, and the bottom surface of the groove is parallel to the central axis of the primary shaft; the vertical surface of the upper end of the cantilever opposite to the primary shaft is tightly connected with the bottom surface of the groove to avoid cantilever twisting.

7. The stress-strain sensor with secondary temperature self-adaptation function according to claim 5, characterized in that: The main shaft base and the secondary shaft base are of the same height, and the bottom planes of the main shaft base and the secondary shaft base are coplanar, and the top planes of the main shaft base and the secondary shaft base are coplanar.

8. The stress-strain sensor with secondary temperature self-adaptation function according to claim 1, characterized in that: The stress strain sensor also includes a communication interface chip connected to the data processing chip, and exchanges data with the terminal device through the communication interface chip.

9. An application of a stress-strain sensor with secondary temperature adaptive function, characterized in that: The stress-strain sensor is installed on the measured structure, large equipment or large bridge to monitor the deformation caused by the stress.

10. An application method of a stress-strain sensor with secondary temperature self-adaptation function, characterized in that: The stress strain sensor is the stress strain sensor according to any one of claims 1 to 8; the application method comprises the following steps: S10. Install the stress and strain sensor on the surface of the measured structure along the measuring direction; S11. Preset a temperature change cycle, apply the temperature sensor built into the data acquisition chip to obtain a constant combination, and write it into the data processing chip to complete the configuration of the correction model; S12. When the structure under test is deformed by stress, the pull rod drives the bottom end of the boom to move, further stretching the first sensitive grid and compressing the second sensitive grid, and the data acquisition chip obtains the stress and strain analog signals output by the first sensitive grid and the second sensitive grid; When the measured structure is deformed by stress, it is also deformed by the ambient temperature, and the deformation caused by the temperature change is consistent with the deformation of the temperature sensitive unit, so that the first sensitive grid and the second sensitive grid do not deform, that is, the deformation caused by the temperature change is not output through the first sensitive grid and the second sensitive grid; S13. The data acquisition chip receives the stress-strain analog signal after a temperature adaptation and converts it into a stress-strain digital signal after a temperature adaptation; S14. The data processing chip receives the stress-strain digital signal after the first temperature self-adaptation, and obtains the stress-strain digital signal after the second temperature self-adaptation after correction by the correction model.

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