Intelligent bridge circuit balanced strain measurement system and method for large spacecraft

Abstract

The application provides an intelligent bridge balance strain measurement system and method for large spacecraft. In view of the defects of low efficiency, poor precision, weak anti-interference and insufficient multi-channel cooperation of traditional manual balancing, the system is composed of strain detection, strain bridge, data acquisition, PLC, touch display and signal processing modules, 0.2% high-precision potentiometer is used to realize electronic balancing of the bridge, signal shielding line is matched to suppress electromagnetic interference, and touch screen array realizes real-time visualization of 100-channel balancing state. The measurement method is completed through six steps of strain gauge installation and wiring, system initialization, voltage acquisition and processing, visualization leveling, signal amplification and conversion and upper computer analysis. The application eliminates manual operation error, single-channel leveling is less than or equal to 5s, 100-channel overall leveling is less than or equal to 500s, strain measurement error is less than or equal to ±0.5%με, test preparation efficiency is improved by more than 85%, and the strain measurement demand of large-scale, high-precision and high-reliability ground mechanical test of large spacecraft is met.

Description

Technical Field

[0001] This invention relates to the field of strain measurement technology, and more specifically, to an intelligent bridge balance strain measurement system and method for large spacecraft. Background Technology

[0002] Large spacecraft have complex structures and a large number of measurement points. In ground-based mechanical and vibration tests, strain measurement is a core means of evaluating structural strength, stiffness, and mechanical response. Its measurement accuracy and data reliability directly determine the results of spacecraft structural design verification and safety assessment. Strain measurement generally adopts the Wheatstone bridge principle, and bridge balance is a prerequisite for ensuring accurate strain signal output. Traditional strain measurement systems rely on manual balancing as the core process, forming a fixed testing paradigm. However, under the testing requirements of large spacecraft with multiple measurement points, high precision, and fast pace, its limitations are becoming increasingly prominent.

[0003] Currently, mainstream strain gauge bridge balancing technologies are mainly divided into two categories: The first category is traditional manual balancing technology, which relies on manual measurement of strain gauges and cable resistance values, and bridge balancing is achieved by pressing fixed resistors. This method requires technicians to measure and repeatedly match resistors channel by channel. Due to the limitations of the specification accuracy of fixed resistors, it is difficult to achieve ideal balance. At the same time, large spacecraft can have hundreds of measurement points and channels, making manual balancing extremely time-consuming. Furthermore, differences in cable length and human operation errors can introduce additional measurement deviations, and the signal is susceptible to electromagnetic interference, failing to meet the requirements of large-scale, high-precision testing. The second category is simple automatic / semi-automatic zeroing technology. For example, patent CN113238602A uses digital potentiometers to achieve bridge balancing, and patent CN120351955A compensates for offset voltage through a manual zeroing module. However, this type of technology only achieves local zeroing of a single channel and does not form a multi-channel centralized monitoring and collaborative adjustment architecture. Some solutions lack real-time visual feedback, have insufficient adjustment accuracy, and do not design shielding and anti-interference mechanisms for the long-distance cables and multi-channel parallel scenarios of large spacecraft, making them unsuitable for the harsh environment of spacecraft testing.

[0004] In addition, existing strain measurement systems generally suffer from problems such as weak multi-channel coordination capabilities, unintuitive data display, and disconnect between adjustment and acquisition: most systems only support independent adjustment of a single channel and lack a centralized display and control interface; the bridge balance status cannot be visualized in real time, making it difficult for operators to quickly locate abnormal channels; the signal conditioning and data acquisition processes are separated, making weak strain signals susceptible to interference, ultimately resulting in long measurement preparation cycles, large human errors, and unstable data quality, which cannot meet the engineering requirements of high-density measurement points and high-precision measurement for large spacecraft.

[0005] In summary, existing strain bridge balancing measurement technologies have shortcomings: traditional manual balancing relies on manually pressing resistors, which is cumbersome, time-consuming, and labor-intensive, and cannot meet the high-efficiency testing requirements of hundreds of measurement points on large spacecraft; the fixed resistor matching accuracy is limited, and differences in cable resistance and manual operation introduce a large number of errors, resulting in low bridge balancing accuracy and affecting the accuracy of strain measurement; existing semi-automatic balancing schemes lack multi-channel centralized visual monitoring, making the adjustment process unintuitive and the abnormal channel location efficiency low; the system lacks anti-interference design and intelligent collaborative architecture, resulting in poor signal stability under long-distance transmission and failing to meet the high reliability requirements of spacecraft testing.

[0006] Therefore, there is an urgent need in this field for an integrated, intelligent, multi-channel parallel bridge balance strain measurement system that can replace the manual balancing process by using high-precision adjustable resistors, centralized real-time monitoring, and standardized signal conditioning, thereby shortening the test preparation time and improving the accuracy, efficiency, and reliability of strain measurement. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the purpose of this invention is to provide an intelligent bridge balance strain measurement system and method for large spacecraft.

[0008] The present invention provides an intelligent bridge-circuit balanced strain measurement system for large spacecraft, comprising: a strain detection module, a strain bridge module, a data acquisition module, a PLC module, a touch display module, and a signal processing module; The strain detection module is connected to the strain bridge module, and the strain bridge module is sequentially connected to the data acquisition module, the PLC module, and the touch display module. The signal processing module is connected to the strain bridge module. The strain detection module is used to detect strain changes in large spacecraft structures. The strain bridge module is used to receive and process data transmitted by the strain detection module; The data acquisition module is used to acquire the voltage signal of the strain gauge bridge circuit; The PLC module is used to process the voltage signal and transmit it to the touch display module; The touch display module is used to display the bridge voltage values ​​of each channel in real time. The signal processing module is used to process the weak voltage signal output by the strain bridge circuit and to complete the measurement and analysis of strain data.

[0009] Preferably, the strain detection module includes a strain gauge, terminals, a short cable, and a long cable; One end of the short cable is connected to the strain gauge, and the other end is connected to the long cable through a terminal block. The end of the long cable away from the terminal block is connected to the strain gauge bridge module to transmit the resistance change signal of the strain gauge. All strain gauges are connected to one end of a short cable by welding and securing them with tape.

[0010] Preferably, the length of the short cable is 5-8m; The strain gauges are bonded to the critical structural surfaces of the spacecraft using epoxy resin adhesive. The structural surfaces must be cleaned before bonding.

[0011] Preferably, the strain gauge bridge module includes a strain gauge bridge, a high-precision potentiometer, and a signal shielding wire; The two ends of the high-precision potentiometer are connected to a strain gauge bridge via signal shielding wires. The high-precision potentiometer is equipped with a manual adjustment knob with an adjustment accuracy of 0.2%. The operator can adjust the resistance of the potentiometer by rotating the knob according to the voltage value displayed on the touch display module until the voltage value reaches the preset balance threshold. The -EG interface of the strain gauge bridge is connected to one end of the high-precision potentiometer via a signal shielding wire, and the Vi+ interface of the strain gauge bridge is connected to the other end of the high-precision potentiometer via another signal shielding wire.

[0012] Preferably, the data acquisition module supports the Modbus RTU communication protocol to communicate with the PLC module.

[0013] Preferably, the PLC module includes PLC hardware and a DC power supply; The PLC hardware is used to process the collected bridge voltage signal and transmit it to the touch display module, and the DC power supply provides power to the PLC hardware.

[0014] Preferably, the touch display module includes a touch screen array; The touchscreen array supports TCP / IP communication with the PLC hardware; the touch display module communicates with the PLC module in real time via TCP / IP protocol, and can simultaneously display the bridge voltage values ​​of 100 channels.

[0015] Preferably, the signal processing module includes an amplifier signal line, a programmable amplifier, a signal conversion and acquisition unit, and a host computer; One end of the amplifier signal line is connected to the strain bridge circuit, and the other end is connected to the programmable amplifier to receive weak voltage change signals. After being amplified by the programmable amplifier, the signals are transmitted to the signal conversion and acquisition unit. The signal conversion and acquisition unit communicates with the host computer and transmits signals, and the host computer completes the measurement and analysis of strain data.

[0016] Preferably, the high-precision potentiometer is a digitally programmable potentiometer; According to the present invention, an intelligent bridge circuit balance strain measurement method for large spacecraft is provided, employing the aforementioned system. The measurement method includes: Step S1: Fix the strain gauge to the surface of the critical structure of the large spacecraft. Weld one end of the strain gauge to the short cable and protect it with tape. Connect the other end of the short cable to the long cable 4 through the terminal block. Connect the other end of the long cable to the +EG and Vi+ interfaces of the strain bridge circuit to complete the multi-channel wiring. Step S2: The DC power supply powers the PLC hardware, and the data acquisition module, touch screen array, programmable amplifier, and signal conversion acquisition unit are powered on in sequence; the PLC hardware communicates with the data acquisition module through Modbus RTU, and the PLC hardware establishes TCP / IP communication with the touch screen array; Step S3: The data acquisition module synchronously acquires the voltage signal between Vi+ and GND of the strain gauge bridge; the acquired data is uploaded to the PLC hardware via Modbus RTU; the PLC hardware processes the voltage signal of each channel and outputs a voltage value with an accuracy of 0.01V. Step S4: The PLC hardware sends the processed voltage value to the touch screen array via TCP / IP, and displays the voltage value of each channel in real time; when the voltage exceeds the balance threshold, the operator rotates the adjustment knob of the high-precision potentiometer of the corresponding channel and observes the voltage change of the touch screen array in real time until the bridge balance is completed. Step S5: After the bridge circuit is balanced, the tiny resistance change generated by the strain gauge under load is converted into a weak voltage signal of the strain bridge circuit; this signal is sent to the programmable amplifier for amplification via the amplifier signal line; the amplified analog signal is converted into a digital signal by the signal conversion acquisition unit. Step S6: The digital signal is uploaded to the host computer by the signal conversion and acquisition device; the host computer receives the data from each channel and completes strain calculation, data storage and result analysis to realize the accurate measurement of strain of large spacecraft structures.

[0017] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention achieves electronic resistance balancing by introducing high-precision potentiometers, multi-channel signal acquisition modules, PLC systems, and touch screens, eliminating manual crimping steps, thereby effectively shortening test preparation and debugging time, reducing errors caused by human operation, and improving overall work efficiency.

[0018] 2. This invention is equipped with a high-precision potentiometer with an adjustment accuracy of 0.2%, which can achieve precise balance of the bridge circuit. At the same time, the signal shielding wire in the strain bridge circuit module can effectively isolate external electromagnetic interference, so that the weak voltage signal output by the strain bridge circuit is not disturbed. Combined with PLC modular data processing, compared with traditional solutions, it effectively suppresses electromagnetic interference, ensures stable transmission of strain signals, and improves the accuracy and reliability of measurement data.

[0019] 3. The application of the touch screen array in this invention enables real-time visualization of the balance status data of 100 sets of resistor bridge circuits, allowing operators to quickly and intuitively monitor system status and data changes. Attached Figure Description

[0020] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 This is a schematic diagram of the strain measurement system based on intelligent bridge balancing in this invention. Figure 2 This is a schematic diagram of the connection structure of the strain measurement system based on intelligent bridge balancing in this invention; In the diagram, 1-strain gauge, 2-short cable, 3-terminal block, 4-long cable, 5-high-precision potentiometer, 6-signal shielding cable, 7-strain bridge circuit, 8-data acquisition module, 9-PLC hardware, 10-DC power supply, 11-touch screen array, 12-amplifier signal line, 13-programmable amplifier, 14-signal converter and acquisition unit, 15-host computer; Figure 3 The figure shows the time-domain response curve of strain measurement and the data accuracy verification results under the ground mechanical test environment of a large spacecraft. Detailed Implementation

[0021] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0022] Example 1 The present invention provides an intelligent bridge-circuit balanced strain measurement system for large spacecraft, aiming to solve the problems of long strain measurement preparation cycles, manual resistor matching, and poor data measurement quality during large spacecraft testing. Figure 1 and Figure 2 As shown, the system includes: a strain detection module, a strain bridge module, a data acquisition module, a PLC module, a touch display module, and a signal processing module. The system acquires structural strain signals through the strain detection module, uses the strain bridge module in conjunction with a high-precision potentiometer to achieve intelligent resistance balancing, and then the data acquisition module and PLC module complete signal acquisition and efficient processing. Finally, the bridge balance status is displayed in real time through a touch screen array, while the signal processing module performs accurate analysis of the strain data.

[0023] Specifically, the strain detection module is used to detect strain changes in the structure of large spacecraft, and includes strain gauges 1, terminals 3, short cables 2, and long cables 4. One end of the short cable is connected to the strain gauge, and the other end is connected to the long cable via the terminals. The end of the long cable furthest from the terminals is connected to the strain bridge module 6 to transmit the resistance change signal of the strain gauges. All strain gauges are connected to one end of the short cables by welding and securing them with tape. The short cables are 5-8m long to accommodate the cable arrangement within the confined space of large spacecraft. Specifically, the short cables are connected to the long cables via the terminals, and the other end of the long cables is connected to the +EG and Vi+ interfaces of the strain bridge to transmit the resistance change of the strain gauges to the strain bridge.

[0024] When a strain gauge is subjected to external force, its length and cross-sectional area change, which, according to the resistance strain effect, causes a change in its resistance. This change is transmitted through the short cable, whose design allows for easier installation in compact or hard-to-reach areas of large spacecraft, effectively simplifying cable routing and ensuring efficient operation even in complex wiring environments.

[0025] In a preferred embodiment, the strain gauge can also be glued to the critical structural surface of the spacecraft using epoxy resin adhesive. Before gluing, the structural surface must be cleaned to ensure that the strain gauge fits tightly to the structure and accurately transmits strain signals.

[0026] The strain gauge bridge module is used to receive and process data transmitted from the strain detection module. It includes a strain gauge bridge 7, a high-precision potentiometer 5, and a signal shielding cable 6. The two ends of the high-precision potentiometer are connected to the strain gauge bridge via the signal shielding cable. The high-precision potentiometer has a manual adjustment knob with an adjustment accuracy of 0.2%. The operator can adjust the potentiometer resistance by rotating the knob according to the voltage value displayed on the touch screen module until the voltage value reaches a preset balance threshold. The -EG interface of the strain gauge bridge is connected to one end of the high-precision potentiometer via the signal shielding cable, and the Vi+ interface of the strain gauge bridge is connected to the other end of the high-precision potentiometer via another signal shielding cable.

[0027] The data acquisition module 8 is used to acquire the voltage signal of the strain gauge bridge. This module is connected to the strain gauge bridge and supports communication with the PLC module via the Modbus RTU communication protocol. Specifically, the input terminal of the data acquisition module is electrically connected to the Vi+ output terminal and GND terminal of the strain gauge bridge, respectively, to acquire the voltage of the high-precision potentiometer. The communication terminal of the data acquisition module communicates bidirectionally with the communication interface of the PLC hardware via the Modbus RTU protocol to ensure that the acquired bridge voltage signal meets the accuracy requirements of spacecraft strain measurement. Specifically, the data acquisition module is responsible for acquiring the voltage of the high-precision potentiometer. The PLC hardware is powered by the DC power supply, which is a 24V DC regulated power supply with an output current ≥5A, ensuring stable operation of the PLC module during multi-channel data processing. After receiving the voltage value, the PLC hardware calculates the voltage values ​​in all channels and transmits the processed voltage values ​​to the touch screen array via the TCP / IP communication protocol. The operator observes the voltage value of the strain gauge bridge (accuracy = 0.01V) through the touch screen array of the touch display module. When the voltage value exceeds the balance threshold (-0.03V, 0.03V), the operator rotates the manual adjustment knob of the high-precision potentiometer and observes the voltage change displayed on the touch screen array in real time until the voltage value reaches the balance value, thus completing the precise balance adjustment of the strain gauge bridge.

[0028] The PLC module includes PLC hardware 9 and a DC power supply 10. The PLC hardware processes the acquired bridge voltage signal and transmits it to the touch display module, while the DC power supply powers the PLC hardware. The PLC hardware supports Modbus RTU communication to receive voltage information from the data acquisition module and has TCP / IP communication capabilities to transmit data with the touch display module.

[0029] The touch display module is used to display the bridge voltage values ​​of each channel in real time (accuracy = 0.01V), and includes a touch screen array 11. The touch screen array supports TCP / IP communication with the PLC hardware. The touch display module and the PLC module communicate in real time via the TCP / IP protocol, and can simultaneously display the bridge voltage values ​​of 100 channels, facilitating operators to quickly locate the adjustment target and perform feedback adjustments.

[0030] The signal processing module is used to process the weak voltage signal output by the strain gauge bridge and to complete the measurement and analysis of strain data. It includes an amplifier signal line 12, a programmable amplifier 13, a signal converter / acquisition unit 14, and a host computer 15. One end of the signal amplification line is connected to the strain gauge bridge, and the other end is connected to the programmable amplifier. The programmable amplifier is connected to the signal converter / acquisition unit, which is then connected to the host computer. Specifically, one end of the amplifier signal line is connected to the strain gauge bridge, and the other end is connected to the programmable amplifier to receive weak voltage change signals. After amplification by the programmable amplifier, the signals are transmitted to the signal converter / acquisition unit. The signal converter / acquisition unit communicates with the host computer and transmits signals, allowing the host computer to complete the measurement and analysis of strain data. When the strain gauge deforms, the weak voltage change in the strain gauge bridge is transmitted to the programmable amplifier through the amplifier signal line. The programmable amplifier transmits the amplified voltage signal to the signal converter / acquisition unit, which converts the analog signal into a digital signal and sends it to the host computer via a network cable. The host computer acquires the strain data from each channel and completes the strain measurement.

[0031] Example 2 This embodiment provides an intelligent bridge balance strain measurement method for large spacecraft based on the system described in Embodiment 1. This method transforms the traditional, cumbersome, and inefficient manual balancing process into a standardized, efficient, and high-precision intelligent operation process. The steps include: Step S1: Strain gauge installation and cable connection. Fix the strain gauge to the surface of the critical structure of the large spacecraft. One end of the strain gauge 1 is soldered to the short cable 2 and protected with tape. The other end of the short cable 2 is connected to the long cable 4 via the terminal block 3. The other end of the long cable 4 is connected to the +EG and Vi+ interfaces of the strain bridge circuit 7 to complete the multi-channel wiring.

[0032] Step S2: System power-on and communication initialization are completed. 24V DC power supply 10 powers PLC hardware 9; data acquisition module 8, touch screen array 11, programmable amplifier 13, and signal conversion acquisition unit 14 are powered on sequentially; PLC hardware 9 communicates with data acquisition module 8 via Modbus RTU, and PLC hardware 9 establishes TCP / IP communication with touch screen array 11.

[0033] Step S3: Real-time acquisition and processing of bridge voltage data. Module 8 synchronously acquires the voltage signal between Vi+ and GND of strain gauge bridge 7; the acquired data is uploaded to PLC hardware 9 via Modbus RTU; PLC hardware 9 processes the voltage signals of each channel and outputs a voltage value with an accuracy of 0.01V.

[0034] Step S4: Visual monitoring and bridge balance adjustment. The PLC hardware 9 sends the processed voltage value to the touch screen array 11 via TCP / IP, displaying the voltage values ​​of each channel in real time. When the voltage exceeds the balance threshold (-0.03 V to +0.03 V), the operator rotates the adjustment knob of the high-precision potentiometer 5 of the corresponding channel and observes the voltage change of the touch screen array 11 in real time until the bridge balance is completed.

[0035] Step S5: Strain signal amplification and analog-to-digital conversion. After the bridge circuit is balanced, the tiny resistance change generated by the strain gauge under load is converted into a weak voltage signal of the strain bridge circuit 7; this signal is sent to the programmable amplifier 13 for amplification via the amplifier signal line 12; the amplified analog signal is converted into a digital signal by the signal conversion acquisition unit 14.

[0036] Step S6: Strain data transmission, calculation and analysis. Digital signals are uploaded to the host computer 15 by the signal conversion and acquisition unit 14; the host computer 15 receives data from each channel and completes strain calculation, data storage and result analysis, realizing accurate measurement of strain in large spacecraft structures.

[0037] Next, the intelligent bridge balance strain measurement method for large spacecraft of the present invention is described in detail according to specific experimental parameters as follows: Test parameters: Test channels: 100 channels, short cable length: 6 m, long cable length: 15 m, voltage display accuracy: 0.01 V, sampling frequency: 1600 Hz, sensitivity: 1 mV / μE, test environment: large spacecraft ground mechanical test Experimental results: Bridge balancing performance: Single-channel balancing time: ≤5s; Overall balancing time for 100 channels: ≤500s; Bridge voltage deviation after balancing: ≤±0.015V, meeting the -0.03V~+0.03V balancing threshold requirement. Compared to traditional manual balancing: Test preparation efficiency improved by over 85%. Strain measurement results, such as Figure 3Figure 3 shows the time-domain response curve of strain measurement for a single channel and the verification results of data accuracy under the ground mechanical test environment of a large spacecraft. From Figure 3, the following measurement conclusions can be drawn: the channel strain signal output is smooth, without clutter or baseline drift, and no signal distortion caused by electromagnetic interference occurs. This verifies that the system's signal shielding and anti-interference design can effectively ensure the integrity of weak strain signals under long-distance cable transmission; the strain measurement data highly matches the theoretical mechanical response trend of the spacecraft structure, with a measured strain error ≤ ±0.5%με, meeting the technical requirements for high-precision strain measurement of large spacecraft; the channel signal acquisition synchronization delay is ≤1ms, with high matching degree with the 1600Hz high-speed sampling frequency, which can truly reproduce the dynamic strain response characteristics of the large spacecraft structure; during continuous acquisition after bridge balancing, the strain signal has no offset or distortion, and the system can support stable measurement during long-term ground mechanical tests of large spacecraft.

[0038] Example 3 As an optional implementation, this embodiment provides a more automated, improved intelligent bridge balancing strain measurement system based on Embodiment 1. In Embodiment 1, the bridge balancing adjustment is performed manually by an operator rotating a high-precision potentiometer 5. Although this significantly improves efficiency compared to traditional techniques, manual adjustment still requires considerable time and manpower for ultra-large-scale testing with thousands of channels. This embodiment aims to further reduce or even eliminate manual operation to achieve fully automated bridge balancing.

[0039] In this improved system, the original manual high-precision potentiometer 5 has been replaced with a digitally programmable potentiometer. It is understood that a digitally programmable potentiometer is a solid-state electronic device whose equivalent resistance value can be precisely controlled via digital signals (e.g., through digital interfaces such as I2C, SPI, or parallel ports).

[0040] The overall structure of the system is similar to that of Example 1, but the functionality of the PLC module has been expanded. It not only collects and displays the bridge voltage but also undertakes the decision-making and execution functions of closed-loop control. The specific workflow is as follows: Step 1: The PLC hardware 9 reads the offset voltage value of a certain channel, for example, +0.5V, through the data acquisition module 8.

[0041] Step 2: The control algorithm inside the PLC hardware 9 determines that the value exceeds the balance threshold (-0.03V to +0.03V).

[0042] Step 3: Based on the preset control model (such as PID control algorithm or simple proportional control algorithm) and the characteristic parameters of the digital potentiometer of the channel, the PLC hardware 9 calculates the adjustment command that needs to be sent to the digital potentiometer of the channel to reduce its resistance value to offset the positive offset voltage.

[0043] Step 4: PLC hardware 9 sends control commands (e.g., a series of SPI bus signals) to the digital programmable potentiometer corresponding to the channel through its digital output interface.

[0044] Step 5: After receiving the instruction, the digital programmable potentiometer changes the state of its internal resistor array switch, so that its equivalent resistance value changes precisely to the target value.

[0045] Step 6: After the bridge resistance changes, its offset voltage also changes. The PLC hardware 9 will read a new voltage value that is closer to zero (e.g., +0.1V) in the next acquisition cycle.

[0046] PLC hardware 9 repeats steps 2 to 6 above, iteratively adjusting until the voltage value of the channel is adjusted to within the balance threshold.

[0047] Meanwhile, the PLC hardware 9 sends the real-time voltage values ​​and adjustment status (e.g., adjusting, balanced, fault) of all channels to the touchscreen array 11. At this point, the operator's role changes from executor to supervisor; they can observe the balancing process of all channels on the screen, seeing unbalanced channels automatically and quickly become balanced one by one. If a channel fails to automatically balance for an extended period, the system will mark it as faulty and trigger an alarm, allowing the operator to then intervene and check for problems with the physical connections or components of that channel.

[0048] This embodiment achieves fully automated bridge balancing by employing digitally programmable potentiometers and extended PLC control algorithms. Its advantages include: 1. Reduced balancing time: For large-scale testing systems, manual adjustment time of tens of minutes can be reduced to tens of seconds, significantly improving efficiency; 2. Complete elimination of errors and inconsistencies introduced by manual adjustment: the balancing accuracy of all channels is guaranteed by the algorithm and device precision, resulting in extremely high consistency and repeatability; 3. Further reduced reliance on operator skills, simplified testing procedures, and lower labor costs.

[0049] Those skilled in the art will understand that, besides implementing the system and its various devices, modules, and units provided by this invention in the form of purely computer-readable program code, the same functions can be achieved entirely through logical programming of the method steps, making the system and its various devices, modules, and units of this invention function in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, and embedded microcontrollers. Therefore, the system and its various devices, modules, and units provided by this invention can be considered as a hardware component, and the devices, modules, and units included therein for implementing various functions can also be considered as structures within the hardware component; alternatively, the devices, modules, and units for implementing various functions can be considered as both software modules implementing the method and structures within the hardware component.

[0050] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. An intelligent bridge-circuit balance strain measurement system for large spacecraft, characterized in that, include: Strain detection module, strain bridge module, data acquisition module, PLC module, touch display module, and signal processing module; The strain detection module is connected to the strain bridge module, which is sequentially connected to the data acquisition module, the PLC module, and the touch display module. The signal processing module is connected to the strain bridge module. The strain detection module is used to detect strain changes in large spacecraft structures. The strain bridge module is used to receive and process data transmitted by the strain detection module; The data acquisition module is used to acquire the voltage signal of the strain gauge bridge circuit; The PLC module is used to process the voltage signal and transmit it to the touch display module; The touch display module is used to display the bridge voltage values ​​of each channel in real time. The signal processing module is used to process the weak voltage signal output by the strain bridge circuit and to complete the measurement and analysis of strain data.

2. The intelligent bridge-circuit balance strain measurement system for large spacecraft according to claim 1, characterized in that, The strain detection module includes strain gauges, terminals, short cables, and long cables; One end of the short cable is connected to the strain gauge, and the other end is connected to the long cable through a terminal block. The end of the long cable away from the terminal block is connected to the strain gauge bridge module to transmit the resistance change signal of the strain gauge. All strain gauges are connected to one end of a short cable by welding and securing them with tape.

3. The intelligent bridge-circuit balance strain measurement system for large spacecraft according to claim 2, characterized in that, The length of the short cable is 5-8m; The strain gauges are bonded to the critical structural surfaces of the spacecraft using epoxy resin adhesive. The structural surfaces must be cleaned before bonding.

4. The intelligent bridge-circuit balance strain measurement system for large spacecraft according to claim 1, characterized in that, The strain gauge bridge module includes a strain gauge bridge, a high-precision potentiometer, and a signal shielding wire; The two ends of the high-precision potentiometer are connected to a strain gauge bridge via signal shielding wires. The high-precision potentiometer is equipped with a manual adjustment knob with an adjustment accuracy of 0.2%. The operator can adjust the resistance of the potentiometer by rotating the knob according to the voltage value displayed on the touch display module until the voltage value reaches the preset balance threshold. The -EG interface of the strain gauge bridge is connected to one end of the high-precision potentiometer via a signal shielding wire, and the Vi+ interface of the strain gauge bridge is connected to the other end of the high-precision potentiometer via another signal shielding wire.

5. The intelligent bridge-circuit balance strain measurement system for large spacecraft according to claim 1, characterized in that, The data acquisition module supports the Modbus RTU communication protocol to communicate with the PLC module.

6. The intelligent bridge-circuit balance strain measurement system for large spacecraft according to claim 1, characterized in that, The PLC module includes PLC hardware and a DC power supply; The PLC hardware is used to process the collected bridge voltage signal and transmit it to the touch display module, and the DC power supply provides power to the PLC hardware.

7. The intelligent bridge-circuit balance strain measurement system for large spacecraft according to claim 1, characterized in that, The touch display module includes a touch screen array; The touchscreen array supports TCP / IP communication with the PLC hardware; the touch display module communicates with the PLC module in real time via TCP / IP protocol, and can simultaneously display the bridge voltage values ​​of 100 channels.

8. The intelligent bridge-circuit balance strain measurement system for large spacecraft according to claim 1, characterized in that, The signal processing module includes an amplifier signal line, a programmable amplifier, a signal conversion and acquisition unit, and a host computer. One end of the amplifier signal line is connected to the strain bridge circuit, and the other end is connected to the programmable amplifier to receive weak voltage change signals. After being amplified by the programmable amplifier, the signals are transmitted to the signal conversion and acquisition unit. The signal conversion and acquisition unit communicates with the host computer and transmits signals, and the host computer completes the measurement and analysis of strain data.

9. The intelligent bridge-circuit balance strain measurement system for large spacecraft according to claim 4, characterized in that, The high-precision potentiometer is a digitally programmable potentiometer.

10. A method for measuring the strain balance of an intelligent bridge circuit in a large spacecraft, characterized in that, Using the system according to any one of claims 1 to 8, the measurement method includes: Step S1: Fix the strain gauge to the surface of the critical structure of the large spacecraft. Weld one end of the strain gauge to the short cable and protect it with tape. Connect the other end of the short cable to the long cable 4 through the terminal block. Connect the other end of the long cable to the +EG and Vi+ interfaces of the strain bridge circuit to complete the multi-channel wiring. Step S2: The DC power supply powers the PLC hardware, and the data acquisition module, touch screen array, programmable amplifier, and signal conversion acquisition unit are powered on in sequence; the PLC hardware communicates with the data acquisition module through Modbus RTU, and the PLC hardware establishes TCP / IP communication with the touch screen array; Step S3: The data acquisition module synchronously acquires the voltage signal between Vi+ and GND of the strain gauge bridge; the acquired data is uploaded to the PLC hardware via Modbus RTU; the PLC hardware processes the voltage signal of each channel and outputs a voltage value with an accuracy of 0.01V. Step S4: The PLC hardware sends the processed voltage value to the touch screen array via TCP / IP, and displays the voltage value of each channel in real time; when the voltage exceeds the balance threshold, the operator rotates the adjustment knob of the high-precision potentiometer of the corresponding channel and observes the voltage change of the touch screen array in real time until the bridge balance is completed. Step S5: After the bridge circuit is balanced, the tiny resistance change generated by the strain gauge under load is converted into a weak voltage signal of the strain bridge circuit; this signal is sent to the programmable amplifier for amplification via the amplifier signal line; the amplified analog signal is converted into a digital signal by the signal conversion acquisition unit. Step S6: The digital signal is uploaded to the host computer by the signal conversion and acquisition device; the host computer receives the data from each channel and completes strain calculation, data storage and result analysis to realize the accurate measurement of strain of large spacecraft structures.

Images