A strain measurement channel multiplexing method
By using a strain measurement channel multiplexing method, and utilizing MOS transistor components and control modules to achieve multiple switching of strain gauges, the problem of insufficient strain acquisition equipment in aircraft structural strength testing is solved, and the equipment utilization rate and measurement accuracy are improved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHINA AIRPLANT STRENGTH RES INST
- Filing Date
- 2026-02-02
- Publication Date
- 2026-06-05
AI Technical Summary
In aircraft structural strength testing, there is a shortage of strain acquisition equipment when multiple tests are conducted in parallel, resulting in significant equipment and financial pressures, unstable resource allocation, and an inability to meet the requirements of parallel testing of multiple models.
By adopting a strain measurement channel multiplexing method, a multiplexing switching circuit is designed, and MOS transistor components and control modules are used to realize the multiple switching of strain gauges, thereby improving the equipment utilization rate.
It improves the utilization rate of strain acquisition equipment, ensures the zero-point stability and indication stability of the strain acquisition system, reduces indication errors, and meets the needs of multiple strength tests conducted in parallel.
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Figure CN122149306A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of aircraft structural strength testing, and in particular to a method for multiplexing strain measurement channels. Background Technology
[0002] For static strength tests of aircraft structures, a large number of strain measurement points need to be deployed, along with corresponding strain measurement channels. Due to the massive scale of strain measurement points in full-aircraft strength tests—typically around 5,000 channels for small aircraft, 10,000 for medium-sized aircraft, and 20,000 for large aircraft—if each measurement point were configured with a corresponding acquisition channel for different aircraft models, the scale of data acquisition channels would be considerable. The test schedule for each model would also be affected by the total number of equipment channels. Deploying acquisition channels according to the total number of models would also create enormous equipment and financial pressure. Considering that strength tests of various aircraft are not always conducted simultaneously, if all test equipment were prepared at once, frequent resource reallocation would be necessary when switching test conditions. This not only introduces instability to the precision data acquisition equipment but also places significant personnel pressure on measurement preparation. Current conventional dynamic resource allocation methods are insufficient to meet the requirements of parallel testing of multiple models, necessitating new approaches to address the shortage of strain acquisition equipment during concurrent strength tests. Summary of the Invention
[0003] In view of this, this application provides a strain measurement channel multiplexing method to solve the problem of insufficient strain acquisition equipment when multiple strength tests are conducted in parallel, and can fully improve the utilization rate of acquisition equipment.
[0004] The strain measurement channel multiplexing method provided in this application adopts the following technical solution:
[0005] A method for multiplexing strain measurement channels includes: Step 1: Design a multi-channel switching circuit. The multi-channel switching circuit includes multiple strain gauge switch circuit modules, an excitation module, and a control module. The strain gauge switch circuit module includes a first MOSFET assembly and a second MOSFET assembly. Both the first and second MOSFET assemblies include multiple MOSFETs connected in parallel. The excitation module provides an excitation signal with a preset voltage to the multiple strain gauge switch circuit modules. The excitation input terminal of the excitation module is electrically connected to the drain of the MOSFET in the first MOSFET assembly, and the excitation output terminal of the excitation module is electrically connected to the source of the MOSFET in the second MOSFET assembly. The control module outputs a switching control signal to the gate of the MOSFET in the first and second MOSFET assemblies. Step 2: Connect multiple strain gauges to a strain switch circuit module. The source of the MOS transistor in the first MOS transistor assembly is electrically connected to one end of the strain gauge, and the drain of the MOS transistor in the second MOS transistor assembly is electrically connected to the other end of the strain gauge. Step 3: Connect the excitation input terminal, excitation output terminal, and strain signal line of the excitation module to the corresponding interfaces on the strain acquisition instrument; Step 4: The control module outputs a control signal to the gate of the MOS transistor in the first MOS transistor assembly and the second MOS transistor assembly corresponding to the selected strain gauge, so as to control the conduction of the first MOS transistor assembly and the second MOS transistor assembly in the corresponding strain switch circuit module, and simultaneously power the selected strain gauge, so as to connect the strain signal of the selected strain gauge to the strain acquisition instrument.
[0006] Optionally, the first MOS transistor assembly and the second MOS transistor assembly are designed as four MOS transistors connected in parallel.
[0007] Optionally, the on-resistance of each MOS transistor in the first MOS transistor assembly and the second MOS transistor assembly is less than or equal to 2.4Ω.
[0008] Optionally, the on-resistance of each MOS transistor in the first MOS transistor assembly and the second MOS transistor assembly changes by less than 80mΩ within 2 hours.
[0009] Optionally, in step 1, the on-resistance of the first MOS transistor assembly and the second MOS transistor assembly is designed to have a flatness of less than 2.5 mΩ / V within the on-signal range.
[0010] Optionally, the preset voltage provided by the excitation module is 2V.
[0011] Optionally, in step 1, a first resistor is designed and connected to the source of the MOS transistor in the second MOS transistor assembly, and the first resistor of the first MOS transistor assembly and the strain gauge form a bridge circuit.
[0012] Optionally, the first resistor is located in the strain gauge, and the resistance of the first resistor is 120Ω or 350Ω.
[0013] Optionally, the circuit board of the multi-channel switching circuit in step 1 adopts an 8-layer PCB design, and the top layer of the PCB is covered by a heat spreader.
[0014] In summary, this application includes the following beneficial technical effects: This application selects different strain switch circuit modules and applies conduction signals through the control module to realize the connection of different strain gauges and complete the corresponding aircraft test measurement tasks, thereby fully improving the utilization rate of the acquisition equipment and solving the problem of insufficient strain acquisition equipment when multiple strength tests are conducted in parallel.
[0015] A symmetrical twin circuit design is adopted to ensure that the switching circuits at both ends of the strain gauge have the same on-resistance.
[0016] After the strain measurement channel multiplexing method of this application is connected to the strain acquisition system, the increase in zero-point stability, indication stability and indication error of the strain acquisition system does not exceed 0.1%. Attached Figure Description
[0017] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0018] Fig. 1 The circuit schematic of the strain gauge switch circuit module; Fig. 2 This is the schematic diagram of a multiplexer circuit; Fig. 3 This is a schematic diagram of the three-wire strain measurement interface in the embodiments of this application. Detailed Implementation
[0019] The embodiments of this application will now be described in detail with reference to the accompanying drawings.
[0020] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. This application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0021] It should be noted that various aspects of embodiments within the scope of the appended claims are described below. It will be apparent that the aspects described herein can be embodied in a wide variety of forms, and any particular structure and / or function described herein is merely illustrative. Based on this application, those skilled in the art will understand that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects set forth herein can be used to implement the device and / or practice the method. Additionally, this device and / or method can be implemented using structures and / or functionalities other than one or more of the aspects set forth herein.
[0022] It should also be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of this application. The illustrations only show the components related to this application and are not drawn according to the number, shape and size of the components in actual implementation. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.
[0023] Furthermore, specific details are provided in the following description to facilitate a thorough understanding of the examples. However, those skilled in the art will understand that the described aspects can be practiced without these specific details.
[0024] This application provides a method for multiplexing strain measurement channels.
[0025] like Figs. 1 to 3 As shown, a strain measurement channel multiplexing method includes: Step 1: Design a multi-channel switching circuit. The multi-channel switching circuit includes multiple strain gauge switch circuit modules, an excitation module, and a control module. The strain gauge switch circuit module includes a first MOSFET assembly and a second MOSFET assembly. Both the first and second MOSFET assemblies include multiple MOSFETs connected in parallel. The excitation module provides an excitation signal with a preset voltage to the multiple strain gauge switch circuit modules. The excitation input terminal of the excitation module is electrically connected to the drain of the MOSFET in the first MOSFET assembly, and the excitation output terminal of the excitation module is electrically connected to the source of the MOSFET in the second MOSFET assembly. The control module outputs a switching control signal to the gate of the MOSFET in the first and second MOSFET assemblies. Step 2: Connect multiple strain gauges to a strain switch circuit module, with different strain switch circuit modules connected to different strain gauges. The source of the MOS transistor in the first MOS transistor assembly is electrically connected to one end of the strain gauge, and the drain of the MOS transistor in the second MOS transistor assembly is electrically connected to the other end of the strain gauge. Step 3: Connect the excitation input terminal, excitation output terminal, and strain signal line of the excitation module to the corresponding interfaces on the strain acquisition instrument; Step 4: The control module outputs a control signal to the gate of the MOS transistor in the first MOS transistor assembly and the second MOS transistor assembly corresponding to the selected strain gauge, so as to control the conduction of the first MOS transistor assembly and the second MOS transistor assembly in the corresponding strain switch circuit module, and simultaneously power the selected strain gauge, so as to connect the strain signal of the selected strain gauge to the strain acquisition instrument.
[0026] In this embodiment, the control module selects a strain switch circuit module and applies a conduction signal to apply a voltage to the gate of the MOS transistor in the first and second MOS transistor assemblies, causing the drain and source of the MOS transistor to be in a conducting state. The excitation voltage is then connected to the parallel MOS circuit of the first MOS transistor assembly connected to the strain gauge of the currently selected strain switch circuit module, thus completing the circuit connection of the strain gauge. The corresponding test aircraft strain configuration is sent to the strain acquisition instrument via the host computer, and the strain output signal of the strain gauge connected to the currently selected strain switch circuit module is connected to the measurement system through the strain cable socket to complete the strain measurement for the aircraft test. By selecting different strain switch circuit modules and applying conduction signals through the control module, the connection of other strain gauges is realized, and the test measurement task of the corresponding aircraft is completed. This significantly improves the utilization rate of the acquisition equipment and solves the problem of insufficient strain acquisition equipment when multiple strength tests are conducted in parallel.
[0027] In this embodiment, the multiplexing circuit includes four strain gauge switch circuit modules.
[0028] In step 3, the excitation input and excitation output of the excitation module are connected to the excitation input interface and excitation output interface of the strain acquisition instrument, and the output signal of the strain gauge is connected to the signal input interface of the strain acquisition instrument.
[0029] In step 1, a first resistor is connected to the source of the MOS transistor in the second MOS transistor assembly. The first MOS transistor assembly, the first resistor in the second MOS transistor assembly, and the strain gauge form a bridge circuit. In this embodiment, the first resistor is located in the strain gauge and is a precision resistor with a resistance of 120Ω or 350Ω.
[0030] The preset voltage provided by the excitation module is 2V.
[0031] The first and second MOSFET assemblies are designed with four MOSFETs connected in parallel. In this embodiment, the first and second MOSFET assemblies form a symmetrical twin circuit design to ensure that the switches at both ends of the strain gauge have the same electrical performance indicators, resulting in the same on-resistance for the switching circuits at both ends of the strain gauge. In this embodiment, the first and second MOSFET assemblies are also designed with current-limiting protection resistors connected in parallel with the MOSFETs to prevent the MOSFETs from burning out due to overcurrent.
[0032] The on-resistance of each MOSFET in the first and second MOSFET assemblies is less than or equal to 2.4Ω. This reduces the on-resistance of the first and second MOSFET assemblies to as low as 0.6Ω. The flatness of the on-resistance of the first and second MOSFET assemblies within the on-signal range is less than 2.5mΩ / V, ensuring that the switching circuit does not adversely affect the accuracy of strain measurement.
[0033] In one embodiment, the combined switch of the strain gauge excitation circuit also adopts a completely symmetrical design. To obtain highly consistent MOSFETs, the purchased MOSFETs are manually selected based on the following principles: approximately the same on-resistance; good on-resistance time stability: on-resistance change less than 80mΩ within 2 hours, and on-resistance difference between the twin switch circuits less than 2.0mΩ within 2 hours; good on-resistance temperature stability: on-resistance change less than 80mΩ when the ambient temperature changes by 25 degrees Celsius, and on-resistance difference between the switches less than 2.0mΩ when the ambient temperature changes by 25 degrees Celsius. MOSFETs with consistent performance are paired into twin circuits. The four switches of the combined switch are respectively from adjacent channels of the same device, ensuring relatively uniform material distribution and ambient temperature of the combined switch, as well as consistent temperature drift of the combined switch in the excitation circuit. Simultaneously, the multi-channel switch circuit is designed using independent components, resulting in MOSFET turn-off isolation greater than 120dB.
[0034] In the embodiments of this application, the circuit board of the multi-channel switching circuit in step 1 adopts an 8-layer PCB design, and the top layer of the PCB board is covered by a heat spreader.
[0035] This application incorporates low-power and thermal balance design in the circuit board. Low power consumption is primarily achieved through the selection of low-power MOSFETs and the use of a regulated precision power supply, resulting in high efficiency and minimal heat generation, thus minimizing heat generation across the entire circuit board. The thermal balance design is mainly reflected in the following aspects: 1. An 8-layer PCB design ensures uniform temperature distribution at the bottom layer of the MOSFETs; 2. A heat spreader is used to cover the upper layer, ensuring uniform heat distribution across the chip; 3. Twin circuits are designed in the same area, ensuring that the twin switching circuits at both ends of the strain gauge are always in the same temperature field, thereby achieving time-drift compensation for temperature drift. This ensures that the zero-point stability and indication stability of the measurement circuit are less than 20 micro-strains.
[0036] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.
Claims
1. A method for multiplexing strain measurement channels, characterized in that, include: Step 1: Design a multi-channel switching circuit. The multi-channel switching circuit includes multiple strain gauge switch circuit modules, an excitation module, and a control module. The strain gauge switch circuit module includes a first MOSFET assembly and a second MOSFET assembly. Both the first and second MOSFET assemblies include multiple MOSFETs connected in parallel. The excitation module is used to provide an excitation signal with a preset voltage to the multiple strain gauge switch circuit modules. The excitation input terminal of the excitation module is electrically connected to the drain of the MOSFET in the first MOSFET assembly, and the excitation output terminal of the excitation module is electrically connected to the source of the MOSFET in the second MOSFET assembly. The control module is used to output switch control signals to the gates of the MOS transistors in the first MOS transistor assembly and the second MOS transistor assembly; Step 2: Connect multiple strain gauges to a strain switch circuit module. The source of the MOS transistor in the first MOS transistor assembly is electrically connected to one end of the strain gauge, and the drain of the MOS transistor in the second MOS transistor assembly is electrically connected to the other end of the strain gauge. Step 3: Connect the excitation input terminal, excitation output terminal, and strain signal line of the excitation module to the corresponding interfaces on the strain acquisition instrument; Step 4: The control module outputs a control signal to the gate of the MOS transistor in the first MOS transistor assembly and the second MOS transistor assembly corresponding to the selected strain gauge, so as to control the conduction of the first MOS transistor assembly and the second MOS transistor assembly in the corresponding strain switch circuit module, and simultaneously power the selected strain gauge, so as to connect the strain signal of the selected strain gauge to the strain acquisition instrument.
2. The strain measurement channel multiplexing method according to claim 1, characterized in that, The first MOS transistor assembly and the second MOS transistor assembly are designed to have four MOS transistors connected in parallel.
3. The strain measurement channel multiplexing method according to claim 2, characterized in that, The on-resistance of each MOS transistor in the first MOS transistor assembly and the second MOS transistor assembly is less than or equal to 2.4Ω.
4. The strain measurement channel multiplexing method according to claim 3, characterized in that, The on-resistance of each MOS transistor in the first MOS transistor assembly and the second MOS transistor assembly changes by less than 80mΩ within 2 hours.
5. The strain measurement channel multiplexing method according to claim 1, characterized in that, In step 1, the on-resistance of the first MOS transistor assembly and the second MOS transistor assembly is designed to have a flatness of less than 2.5mΩ / V within the on-signal range.
6. The strain measurement channel multiplexing method according to claim 1, characterized in that, The preset voltage provided by the excitation module is 2V.
7. The strain measurement channel multiplexing method according to claim 1, characterized in that, In step 1, a first resistor is designed and connected to the source of the MOS transistor in the second MOS transistor assembly, and the first resistor of the first MOS transistor assembly and the strain gauge form a bridge circuit.
8. The strain measurement channel multiplexing method according to claim 7, characterized in that, The first resistor is located in the strain gauge, and its resistance is 120Ω or 350Ω.
9. The strain measurement channel multiplexing method according to claim 1, characterized in that, The circuit board of the multi-channel switching circuit in step 1 adopts an 8-layer PCB design, and the top layer of the PCB is covered by a heat spreader.