A real-time calibrated strain acquisition system

Abstract

The utility model discloses a kind of strain acquisition systems of real-time calibration, the system includes strain gauge, temperature compensation strain gauge, high-frequency pressure sensor, strain data acquisition card, pressure data acquisition card and computer;When the system works, when pressure value reaches preset zero point pressure P0, pressure data acquisition card sends calibration signal to strain data acquisition card through hardware trigger interface;Strain data acquisition card switches to limited point sampling mode immediately, a group of strain data is collected quickly and its mean is calculated, strain zero point offset is updated in this way, and continuous sampling is automatically restored after completion.The utility model realizes the automatic, real-time calibration of strain zero point by pressure trigger, effectively eliminates the influence of temperature drift and long-term zero point drift on measurement accuracy in combination with temperature compensation strain gauge, significantly improves the accuracy and reliability of strain data acquisition, and is especially suitable for high-precision, high-synchronism hydraulic equipment state monitoring and digital twin system.

Description

Technical Field

[0001] This utility model relates to the technical field of high-frequency strain acquisition and digital twin system, specifically a real-time calibrated strain acquisition system. Background Technology

[0002] Strain measurement is a key technology in structural health monitoring, mechanical performance testing, and digital twin systems. Resistance strain gauges are widely used in mechanical, aerospace, and civil engineering fields due to their high sensitivity, fast response, and ease of installation. Their working principle is based on the Wheatstone bridge, calculating the strain value of the structural surface by measuring changes in resistance.

[0003] However, in practical applications, the measurement accuracy of strain gauges is easily affected by various factors, the most prominent being the thermal output effect caused by temperature changes and the zero-point drift phenomenon caused by long-term use. Temperature changes cause variations in the resistance value of the strain gauge, interfering with the extraction of the true strain signal; and during long-term continuous operation, due to material aging, adhesive layer loosening, and other reasons, the initial zero point of the strain gauge will also slowly shift. If not calibrated in time, measurement errors will accumulate, seriously affecting the reliability of the data and the accuracy of the model.

[0004] Especially in hydraulically driven electromechanical equipment or digital twin systems, the strain state of the structure is often closely related to the working pressure of the hydraulic system. Traditional calibration methods mostly rely on manual periodic calibration or hardware zeroing, which cannot achieve real-time, online zero-point correction and is difficult to meet the requirements of high-frequency, high-precision, and real-time applications. In addition, existing systems often lack hardware triggering linkage mechanisms with hydraulic pressure signals, resulting in insufficient synchronization and environmental adaptability of strain data.

[0005] Therefore, it is necessary to develop a method for real-time, automatic zero-point calibration and temperature compensation of strain gauges, especially suitable for digital twin environments with hydraulic systems, to improve the accuracy of strain data, the consistency of system response, and the simulation accuracy of the model. Utility Model Content

[0006] The purpose of this invention is to provide a system for real-time automatic calibration of strain gauge measurement accuracy. By using hydraulic system pressure to calibrate the zero point in real time and temperature compensation, it achieves high-precision real-time acquisition of high-frequency stress. It is particularly suitable for digital twin systems with hydraulic systems to improve the consistency between digital models and physical entities.

[0007] To achieve the above objectives, the technical solution adopted by this utility model is as follows: A real-time calibrated strain acquisition system, characterized in that it includes a strain measurement strain gauge, a temperature compensation strain gauge, a high-frequency pressure sensor, a strain data acquisition card, a pressure data acquisition card, and a computer; The strain gauge for measuring strain is attached to the surface of the mechanical structure of the object being measured to sense structural deformation; the temperature compensation strain gauge is attached near the strain gauge for measuring strain to perform temperature compensation; the strain gauge for measuring strain and the temperature compensation strain gauge are connected together to a Wheatstone bridge to measure the strain value. The high-frequency pressure sensor is installed on the hydraulic system actuator to collect hydraulic pressure signals; The strain data acquisition card is connected to the strain measurement strain gauge and the temperature compensation strain gauge via a first shielded cable, and the pressure data acquisition card is connected to the high-frequency pressure sensor via a second shielded cable; both the strain data acquisition card and the pressure data acquisition card are equipped with an external trigger interface (ATR) and are connected to each other via a trigger signal connection cable to achieve synchronous triggering; The strain data acquisition card is connected to the computer via a first network cable, and the pressure data acquisition card is connected to the computer via a second network cable. The computer runs a data acquisition and control program to process the acquired data, determine triggering conditions, and control the strain zero-point calibration process.

[0008] Preferably, the high-frequency pressure sensor has a response time of 0.1ms and a signal output of 4-20mA.

[0009] Preferably, the maximum single-channel sampling rate of the strain data acquisition card and the pressure data acquisition card is 102.4 kS / s.

[0010] Preferably, the strain data acquisition card supports two working modes: continuous sampling and finite point sampling. The finite point sampling mode is used to acquire a preset number of strain values ​​and calculate the average value to update the zero-point offset of the strain.

[0011] Preferably, the program of the pressure data acquisition card is configured to send a trigger signal to the strain data acquisition card through its ATR interface when the real-time acquired pressure value Px reaches a preset value P0.

[0012] This utility model has the following advantages compared with the prior art: (1) This utility model monitors pressure through a high-frequency pressure sensor. When the pressure reaches the preset point P0, the pressure data acquisition card automatically sends a trigger signal, and the zero-point calibration process of the strain data acquisition card is started through the trigger signal connection cable. No manual intervention is required, which significantly improves the long-term accuracy and reliability of the measurement.

[0013] (2) This utility model directly compensates for measurement errors caused by ambient temperature fluctuations by combining temperature compensation strain gauges and strain measurement strain gauges with a Wheatstone bridge.

[0014] (3) This utility model utilizes the high sampling rate (102.4kS / s) and hardware trigger interface (ATR) of the strain data acquisition card and the pressure data acquisition card, and ensures the synchronization of strain and pressure data through the trigger signal connection cable, which is beneficial for dynamic analysis.

[0015] (4) The entire system of this utility model is automated from data acquisition (through the first shielded cable and the second shielded cable), triggering (through the trigger signal connection cable) to data processing (completed in the computer), reducing labor costs and human error. It provides continuous, accurate, and real-time calibrated strain data for the digital twin system, ensuring the consistency between the virtual model and the physical entity. Attached Figure Description

[0016] Figure 1 This is a hardware layout diagram of this utility model; Figure 2 This is the implementation logic diagram of this utility model; In the diagram: 1. Strain gauge for strain measurement; 2. Temperature-compensated strain gauge; 3. First shielded cable; 4. Strain data acquisition card; 5. Trigger signal connection cable; 6. First network cable; 7. Computer; 8. Second network cable; 9. Pressure data acquisition card; 10. Second shielded cable; 11. High-frequency pressure sensor. Detailed Implementation

[0017] The present invention will be further described in detail below with reference to specific embodiments.

[0018] like Figure 1 As shown, a real-time calibrated strain acquisition system includes a strain gauge 1, a temperature-compensated strain gauge 2, a high-frequency pressure sensor 11, a strain data acquisition card 4, a pressure data acquisition card 9, and a computer 7. The strain gauge 1 is attached to the surface of the mechanical structure of the object being measured to sense structural deformation. The temperature-compensated strain gauge 2 is attached near the strain gauge 1 for temperature compensation. The strain gauge 1 and the temperature-compensated strain gauge 2 are connected to a Wheatstone bridge to measure strain values. The high-frequency pressure sensor 11 is installed on the hydraulic system actuator to acquire hydraulic pressure signals. The strain data acquisition card 4 connects to the computer. The strain data acquisition card 4 is connected to the strain gauge 1 and the temperature compensation strain gauge 2 via the first shielded cable 3, and the pressure data acquisition card 9 is connected to the high-frequency pressure sensor 11 via the second shielded cable 10. Both the strain data acquisition card 4 and the pressure data acquisition card 9 are equipped with an external trigger interface (ATR) and are connected to each other via a trigger signal connection cable 5 to achieve synchronous triggering. The strain data acquisition card 4 is connected to the computer 7 via the first network cable 6, and the pressure data acquisition card 9 is connected to the computer 7 via the second network cable 8. The computer 7 runs a data acquisition and control program to process the acquired data, determine the trigger conditions, and control the strain zero-point calibration process.

[0019] When implementing this system, firstly, strain gauge 1 is attached to the mechanical structure of the equipment under test. Then, a temperature compensation strain gauge 2 is fixed near strain gauge 1, ensuring that the temperature compensation strain gauge 2 does not undergo physical deformation at any time and that its ambient temperature remains consistent with that of strain gauge 1. A high-frequency pressure sensor 11 is then installed on the hydraulic system actuator associated with the mechanical structure.

[0020] Connect the high-frequency pressure sensor 11 to the pressure data acquisition card 9 using the second shielded cable 10. Connect the strain gauge 1 and temperature-compensated strain gauge 2 to the strain data acquisition card 4 using the first shielded cable 3. Connect the strain data acquisition card 4 to the computer 7 using the first network cable 6, and connect the pressure data acquisition card 9 to the computer 7 using the second network cable 8. Finally, connect the external trigger interface (ATR) of the pressure data acquisition card 9 to the strain data acquisition card 4 using the trigger signal connection cable 5.

[0021] The system's implementation logic is as follows: Figure 2 As shown. When the equipment starts, the entire data acquisition system automatically begins. Both pressure data acquisition card 9 and strain data acquisition card 4 enter continuous sampling mode, acquiring the equipment's pressure and strain values ​​in real time and continuously pushing them to computer 7 and the digital twin system. The program in computer 7 determines the pressure value Px transmitted from pressure data acquisition card 9 in real time. When Px reaches the preset value P0, P0 is the hydraulic pressure value corresponding to zero strain in the theoretically calculated mechanical structure, typically 0 MPa. Pressure data acquisition card 9 sends a trigger signal through its ATR interface and trigger signal connection cable 5.

[0022] Upon receiving this trigger signal via its ATR interface, strain data acquisition card 4 immediately stops continuous sampling and switches to the zero-point calibration stage, initiating finite-point sampling. In this example, 50 strain values ​​are selected, taking approximately 0.5 ms at the highest sampling rate. Computer 7 calculates the arithmetic mean of these 50 sampled values ​​and uses this mean as the new strain zero-point offset ε0, updating the program parameters. After completing the zero-point update, strain data acquisition card 4 automatically switches back to continuous sampling mode, continuing to provide the digital twin system with high-precision strain data calibrated in real time.

[0023] The above process is executed cyclically during system operation, thereby achieving continuous, automatic, and real-time calibration of strain data.

[0024] The above are merely preferred embodiments of this utility model. It should be noted that, for those skilled in the art, based on the technical teachings provided by this utility model and as common knowledge in the mechanical field, other equivalent modifications and improvements can be made, and these should also be considered within the scope of protection of this utility model.

Claims

1. A strain acquisition system for real-time calibration, characterized in that: It includes strain gauge (1), temperature compensation strain gauge (2), high frequency pressure sensor (11), strain data acquisition card (4), pressure data acquisition card (9) and computer (7). The strain gauge (1) is attached to the surface of the mechanical structure of the object being measured to sense structural deformation; the temperature compensation strain gauge (2) is attached near the strain gauge (1) to perform temperature compensation; the strain gauge (1) and the temperature compensation strain gauge (2) are connected to a Wheatstone bridge to measure the strain value. The high-frequency pressure sensor (11) is installed on the hydraulic system actuator to collect hydraulic pressure signals; The strain data acquisition card (4) is connected to the strain measurement strain gauge (1) and the temperature compensation strain gauge (2) via the first shielded cable (3), and the pressure data acquisition card (9) is connected to the high-frequency pressure sensor (11) via the second shielded cable (10); both the strain data acquisition card (4) and the pressure data acquisition card (9) are equipped with an external trigger interface (ATR) and are connected to each other via a trigger signal connection cable (5) to achieve synchronous triggering; The strain data acquisition card (4) is connected to the computer (7) via the first network cable (6), and the pressure data acquisition card (9) is connected to the computer (7) via the second network cable (8); The computer (7) runs a data acquisition and control program to process the acquired data, determine the triggering conditions, and control the strain zero-point calibration process.

2. The real-time calibrated strain acquisition system according to claim 1, characterized in that: The high-frequency pressure sensor (11) has a response time of 0.1ms and a signal output of 4-20mA.

3. The strain acquisition system for real-time calibration according to claim 2, characterized in that: The maximum single-channel sampling rate of the strain data acquisition card (4) and the pressure data acquisition card (9) is 102.4 kS / s.

4. The strain acquisition system for real-time calibration according to claim 3, characterized in that: The strain data acquisition card (4) supports two working modes: continuous sampling and finite point sampling. The finite point sampling mode is used to collect a preset number of strain values ​​and calculate the average value to update the zero-point offset of the strain.

5. The real-time calibrated strain acquisition system according to claim 4, characterized in that: The program of the pressure data acquisition card (9) is configured to acquire pressure values ​​P in real time. x When the preset value P0 is reached, a trigger signal is sent to the strain data acquisition card (4) through its ATR interface.

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