Five-axis gantry milling-lathe compound machine tool assembly stress ultrasonic detection method, device, equipment and medium

Abstract

The present application relates to the technical field of nondestructive testing, and provides an assembly stress ultrasonic detection method, device, equipment and medium for a five-axis gantry milling-turning compound machine tool, which comprises the following steps: obtaining an ultrasonic reflection echo signal for a target assembly connection part, wherein the target assembly connection part is located on the five-axis gantry milling-turning compound machine tool; calculating an ultrasonic characteristic parameter representing the current state of the target assembly connection part based on the ultrasonic reflection echo signal; and inputting the ultrasonic characteristic parameter into a pre-established assembly stress calibration model to obtain a current assembly stress value of the target assembly connection part, wherein the assembly stress calibration model comprises a three-level calibration model. Through the technical scheme, the efficiency and accuracy of machine tool assembly stress detection are significantly improved.

Description

Technical Field

[0001] This invention relates to the field of nondestructive testing technology, and in particular to a method, apparatus, equipment and medium for ultrasonic testing of assembly stress in a five-axis gantry milling and turning composite machine tool. Background Technology

[0002] As a high-precision CNC machine tool, the five-axis gantry milling and turning composite machine tool is assembled from key components such as the bed, column, spindle box, and slide through bolt connections, positioning fits, and press fitting. During actual assembly, factors such as component machining errors, mating surface contact, assembly sequence, and bolt tightening process parameters can easily lead to hidden, uneven, and cumulative assembly stress and preload deviations at the machine tool assembly connection points. Unreasonable assembly stress can directly cause micro-deformation of the machine tool structure and, under the influence of operating loads and temperature changes, stress redistribution occurs, resulting in drifts in geometric accuracy such as straightness, parallelism, perpendicularity, and coaxiality. Simultaneously, it deteriorates the stress state of the guide rail pairs and spindle system, causing reduced motion stability, insufficient dynamic stiffness, and increased vibration, seriously affecting the machining accuracy, accuracy retention, and overall reliability of the five-axis gantry milling and turning composite machine tool.

[0003] Currently, the assembly quality control of five-axis gantry milling and turning composite machine tools mainly relies on controlling bolt tightening torque, depending on the experience of assembly personnel, and conducting geometric accuracy inspections after the entire machine is assembled. These traditional methods cannot directly, quickly, and quantitatively detect the stress state of assembly joints during the assembly process, making it difficult to achieve real-time monitoring and closed-loop control of assembly stress. When abnormal assembly stress occurs, corrections can only be made through rework and repeated adjustments to the assembly process, resulting in low assembly efficiency, high costs, and difficulty in ensuring consistent assembly quality across multiple machine tools.

[0004] Although ultrasonic testing technology can be used for non-destructive stress assessment, most existing ultrasonic testing methods can only achieve simple measurement of a single parameter. They lack multi-level calibration and quantitative calculation mechanisms for five-axis gantry milling and turning composite machine tool assembly scenarios. They cannot accurately establish a stable mapping relationship between ultrasonic characteristic parameters and assembly interface stiffness and assembly stress, making it difficult to meet the actual needs of machine tool assembly sites for high-precision, rapid, and online quantitative assembly stress detection. Summary of the Invention

[0005] This invention provides a method, apparatus, equipment, and medium for ultrasonic testing of assembly stress in a five-axis gantry milling and turning composite machine tool. It aims to address the shortcomings of related technologies, such as the lack of a multi-level calibration and quantitative calculation mechanism for five-axis gantry milling and turning composite machine tool assembly scenarios, the inability to accurately establish a stable mapping relationship between ultrasonic characteristic parameters and assembly interface stiffness and assembly stress, and the difficulty in meeting the technical requirements for high-precision, rapid, and online quantitative testing of assembly stress in machine tool assembly sites.

[0006] In a first aspect, embodiments of the present invention provide an ultrasonic testing method for assembly stress in a five-axis gantry milling and turning composite machine tool, the method comprising: Acquire ultrasonic reflected echo signals for the target assembly connection part, wherein the target assembly connection part is located on the five-axis gantry milling and turning composite machine tool; Based on the ultrasonic reflected echo signal, ultrasonic characteristic parameters characterizing the current state of the target assembly connection part are calculated; The ultrasonic characteristic parameters are input into a pre-established assembly stress calibration model to obtain the current assembly stress value of the target assembly connection part. The assembly stress calibration model includes a three-level calibration model.

[0007] In one embodiment, optionally, the process of establishing the three-level calibration model includes: Establish the mapping relationship between the ultrasonic characteristic parameters and the equivalent stiffness of the assembly interface; Through experimental calibration, a quantitative relationship between the equivalent stiffness of the assembly interface and the assembly stress was established. By integrating the mapping relationship and the quantitative relationship, an assembly stress calibration model is formed that ranges from the ultrasonic characteristic parameters to the assembly stress.

[0008] In one embodiment, optionally, the ultrasonic feature system includes an ultrasonic reflection coefficient, and the ultrasonic reflected echo signal includes a reference reflection signal under stress-free conditions and an actually measured reflection signal; Based on the ultrasonic reflected echo signal, ultrasonic characteristic parameters characterizing the current state of the target assembly connection are calculated, including: The ultrasonic reflection coefficient is obtained by calculating the ratio of the first amplitude of the reference reflection signal under stress-free conditions to the second amplitude of the actual measured reflection signal.

[0009] In one embodiment, optionally, the ultrasonic reflection coefficient and the equivalent stiffness of the assembly interface satisfy an ultrasonic interface acoustic model:

[0010] Where R represents the ultrasonic reflection coefficient, Z1 and Z2 represent the acoustic impedance of the media on both sides of the assembly interface, ω represents the ultrasonic angular frequency, K represents the equivalent stiffness of the assembly interface, and i represents the imaginary unit.

[0011] In one embodiment, optionally, the quantitative relationship between the equivalent stiffness of the assembly interface and the assembly stress is calibrated by gradient stress loading experiments, and a continuous mapping model is established by curve fitting or machine learning.

[0012] In one embodiment, the target assembly connection part may optionally include at least one of the following: bed, column, spindle box, slide, guide rail mounting surface, and bolt fastening connection surface of a five-axis gantry milling and turning composite machine tool.

[0013] In one embodiment, optionally, the method further includes: The measured stress data and corresponding ultrasonic characteristic parameters of the target assembly connection parts are collected periodically, and the assembly stress calibration model is updated and iteratively optimized online.

[0014] Secondly, embodiments of the present invention provide an ultrasonic testing device for assembly stress of a five-axis gantry milling and turning composite machine tool, the device comprising: The acquisition module is used to acquire ultrasonic reflected echo signals for the target assembly connection part, wherein the target assembly connection part is located on the five-axis gantry milling and turning composite machine tool. The calculation module is used to calculate ultrasonic characteristic parameters that characterize the current state of the target assembly connection part based on the ultrasonic reflected echo signal. The stress inversion module is used to input the ultrasonic characteristic parameters into a pre-established assembly stress calibration model to obtain the current assembly stress value of the target assembly connection part, wherein the assembly stress calibration model includes a three-level calibration model.

[0015] Thirdly, embodiments of the present invention provide a computer-readable storage medium storing computer-executable instructions, the computer-executable instructions being used to execute the assembly stress ultrasonic testing method for a five-axis gantry milling and turning composite machine tool as described in any one of the embodiments of the first aspect above.

[0016] Fourthly, embodiments of the present invention provide a computer device, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the assembly stress ultrasonic testing method for a five-axis gantry milling and turning composite machine tool as described in any one of the embodiments of the first aspect.

[0017] In the above technical solution, ultrasonic reflected echo signals are acquired for the target assembly connection part, wherein the target assembly connection part is located on the five-axis gantry milling and turning composite machine tool; based on the ultrasonic reflected echo signals, ultrasonic characteristic parameters characterizing the current state of the target assembly connection part are calculated; the ultrasonic characteristic parameters are input into a pre-established assembly stress calibration model to obtain the current assembly stress value of the target assembly connection part, wherein the assembly stress calibration model includes a three-level calibration model. In this invention, by acquiring ultrasonic reflected echo signals from the target assembly connection part of the five-axis gantry milling and turning composite machine tool, calculating the corresponding ultrasonic characteristic parameters, and inputting them into an assembly stress calibration model containing a three-level calibration model, the current assembly stress value of the assembly connection part can be directly, quickly, and quantitatively calculated. This achieves non-destructive testing of assembly stress without disassembling the machine tool or damaging the structure, effectively solving the problems of traditional assembly quality control methods being unable to perform online detection, quantitative evaluation, or real-time feedback and control. It significantly improves the efficiency and accuracy of machine tool assembly stress detection, providing reliable data support and technical assurance for assembly process optimization and assembly quality consistency control. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 A flowchart of an ultrasonic testing method for assembly stress of a five-axis gantry milling and turning composite machine tool according to an embodiment of the present invention is shown.

[0020] Figure 2 A detailed flowchart of an ultrasonic testing method for assembly stress of a five-axis gantry milling and turning composite machine tool according to an embodiment of the present invention is shown.

[0021] Figure 3 A block diagram of an ultrasonic testing device for assembly stress of a five-axis gantry milling and turning machine tool according to an embodiment of the present invention is shown.

[0022] Figure 4 A schematic diagram of the structure of a computer device according to an embodiment of this application is shown.

[0023] Figure 5 Another structural schematic diagram of a computer device according to an embodiment of this application is shown. Detailed Implementation

[0024] To better understand the technical solution of the present invention, the embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0025] It should be understood that the described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0026] The terminology used in the embodiments of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms “a,” “the,” and “the” as used in the embodiments of this invention and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0027] The following detailed description of some embodiments of the present invention is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0028] Please see Figure 1 , Figure 1 A flowchart of an ultrasonic testing method for assembly stress of a five-axis gantry milling and turning composite machine tool according to an embodiment of the present invention is shown.

[0029] like Figure 1 As shown, this embodiment of the invention provides an ultrasonic testing method for assembly stress in a five-axis gantry milling and turning composite machine tool, the method comprising: Step S101: Obtain the ultrasonic reflected echo signal for the target assembly connection part, wherein the target assembly connection part is located on the five-axis gantry milling and turning composite machine tool.

[0030] In one embodiment, the target assembly connection part may optionally include at least one of the following: bed, column, spindle box, slide, guide rail mounting surface, and bolt fastening connection surface of a five-axis gantry milling and turning composite machine tool.

[0031] At key assembly locations such as the bed, column, guideway pair, spindle box, slide, or bolt connection surface of a five-axis gantry milling and turning composite machine tool, ultrasonic transducers are stably attached to the surface to be measured using a coupling agent. Ultrasonic waves are emitted vertically from the ultrasonic transmitting unit to the assembly joint surface. After passing through the joint surface, the ultrasonic waves are reflected and received by the same transducer to form an ultrasonic reflected echo signal, which is used for subsequent stress calculation.

[0032] For example, when inspecting the bolted connection between the column and bed of a five-axis gantry milling and turning composite machine tool, a 5MHz ultrasonic straight probe is placed near the connection surface. The reflected echo waveform at this location is collected by an ultrasonic instrument, and a time-domain electrical signal containing amplitude and time information is obtained, which is the ultrasonic reflected echo signal of the target assembly connection part.

[0033] In this way, the original acoustic signals reflecting the internal stress state of the assembly joint surface can be quickly obtained without disassembling the machine tool or damaging the structure, providing a reliable data basis for subsequent quantitative calculations and realizing non-destructive signal acquisition at the assembly site.

[0034] Step S102: Based on the ultrasonic reflected echo signal, calculate the ultrasonic characteristic parameters that characterize the current state of the target assembly connection part.

[0035] In one embodiment, optionally, the ultrasonic feature system includes an ultrasonic reflection coefficient, and the ultrasonic reflected echo signal includes a reference reflection signal under stress-free conditions and an actually measured reflection signal; Step S102 includes: The ultrasonic reflection coefficient is obtained by calculating the ratio of the first amplitude of the reference reflection signal under stress-free conditions to the second amplitude of the actual measured reflection signal.

[0036] In this step, the acquired echo signal is subjected to amplitude extraction, noise filtering and normalization. The ratio of the amplitude of the reference reflection signal acquired under stress-free conditions to the measured amplitude of the echo signal under actual assembly conditions is calculated to obtain the core parameter that can characterize the contact state of the bonding surface - the ultrasonic reflection coefficient, which is used as the ultrasonic characteristic parameter for subsequent stress calculation.

[0037] For example, the reference signal amplitude of the bed mating surface under no load and no assembly stress was 562 in advance; the echo amplitude was 390 after actual assembly; by calculating the ratio 390 / 562≈0.694, the ultrasonic reflection coefficient R at this location was obtained as 0.694.

[0038] In this way, the complex time-domain waveform is transformed into a single, stable, and quantifiable characteristic parameter, eliminating the influence of waveform interference and coupling differences, enabling the ultrasonic signal to directly reflect the change in interface contact stiffness, and improving the stability and consistency of detection.

[0039] Step S103: Input the ultrasonic characteristic parameters into the pre-established assembly stress calibration model to obtain the current assembly stress value of the target assembly connection part, wherein the assembly stress calibration model includes a three-level calibration model.

[0040] In one embodiment, optionally, the process of establishing the three-level calibration model includes: Step S1031: Establish the mapping relationship between the ultrasonic characteristic parameters and the equivalent stiffness of the assembly interface.

[0041] The interface stiffness K is calculated from the reflection coefficient R using acoustic theory formulas.

[0042] Step S1032: Through experimental calibration, establish a quantitative relationship between the equivalent stiffness of the assembly interface and the assembly stress. Stiffness values ​​corresponding to different stresses are obtained by gradient loading using a tensile testing machine.

[0043] Step S1033: The mapping relationship and the quantitative relationship are fused to form the assembly stress calibration model from the ultrasonic characteristic parameters to the assembly stress. The two are then fused to form a one-stop calculation model of "R→K→stress".

[0044] In this step, the calculated ultrasonic reflection coefficient is input into a pre-established three-level calibration model. The model automatically solves the problem according to the mapping relationship between ultrasonic characteristic parameters → interface equivalent stiffness → assembly stress, and directly outputs the current assembly stress value (MPa) of the target assembly connection part.

[0045] For example, after inputting the reflection coefficient R=0.694 into the three-level calibration model, the model first calculates the equivalent stiffness K of the interface, and then outputs the current assembly stress as 144MPa through the stiffness-stress mapping relationship, thus completing a quantitative test.

[0046] This enables fully automated calculation of ultrasonic signals, physical parameters, and stress values, eliminating the need for manual table lookups and complex calculations. It can complete quantitative stress output within seconds, meeting the needs of rapid, online, and real-time testing at the assembly site.

[0047] In one embodiment, optionally, the ultrasonic reflection coefficient and the equivalent stiffness of the assembly interface satisfy an ultrasonic interface acoustic model: , Where R represents the ultrasonic reflection coefficient, Z1 and Z2 represent the acoustic impedance of the media on both sides of the assembly interface, ω represents the ultrasonic angular frequency, K represents the equivalent stiffness of the assembly interface, and i represents the imaginary unit.

[0048] By using a model based on the ultrasonic interface propagation theory, and substituting the reflection coefficient R, the acoustic impedance of the medium Z1 / Z2, and the angular frequency ω into the formula, the equivalent stiffness K of the assembly joint surface can be uniquely calculated, reflecting the tightness of the joint surface.

[0049] In this way, a precise conversion from acoustic parameters to interface mechanical parameters is achieved through a rigorous physical model, rather than empirical fitting, ensuring that the solution results have a theoretical basis and high accuracy.

[0050] In one embodiment, optionally, the quantitative relationship between the equivalent stiffness of the assembly interface and the assembly stress is calibrated by gradient stress loading experiments, and a continuous mapping model is established by curve fitting or machine learning.

[0051] By applying progressively increasing stresses to the assembled test pieces using a tensile / compression testing machine, and simultaneously measuring the interface stiffness corresponding to each stress level, a continuous mapping relationship is established through curve fitting or machine learning.

[0052] Establish a calibration relationship specific to the assembly scenario, adapt to the characteristics of the machine tool metal mating surface, so that the final stress calculation is more in line with the actual assembly conditions and the test results are more reliable.

[0053] In one embodiment, optionally, the method further includes: The measured stress data and corresponding ultrasonic characteristic parameters of the target assembly connection parts are collected periodically, and the assembly stress calibration model is updated and iteratively optimized online.

[0054] During long-term use, the model continuously collects on-site measured stress and corresponding ultrasonic parameters, and automatically corrects the model coefficients to adapt the model to environmental changes such as temperature, wear, and material batches.

[0055] For example, by collecting 10 sets of calibration data each quarter, the system automatically optimizes the model parameters to keep the detection error within the allowable range. This achieves model self-optimization, long-term high accuracy, avoids detection drift caused by environmental changes and material differences, and improves the stability of the equipment throughout its entire lifecycle.

[0056] This method achieves non-destructive, rapid, quantitative, and online detection of assembly stress in a five-axis gantry milling and turning composite machine tool through ultrasonic echo signal acquisition, characteristic parameter calculation, and three-level calibration model solution. It can acquire assembly stress values ​​of key parts such as the bed, column, guide rail pair, spindle box, and bolt connections in real time, providing a reliable basis for assembly process adjustment, accuracy assurance, and quality consistency control. It fundamentally solves the technical problems of traditional methods that cannot detect online, cannot quantitatively evaluate, and cannot provide real-time feedback.

[0057] The above technical solution of the present invention will be described in detail below with reference to a specific embodiment.

[0058] like Figure 2 As shown, in step 201, the ultrasonic reference signal under stress-free conditions is acquired. After confirming good coupling between the ultrasonic transducer and the specimen interface, the probe position was precisely adjusted to ensure the ultrasonic beam was incident perpendicularly onto the interface. Subsequently, the ultrasonic reference reflection amplitude signal under stress-free conditions was acquired and recorded. ; Step 202: Apply axial load using a tensile testing machine at a gradient rate and calculate the reflection coefficient at the corresponding stress level. Using the tensile testing machine, apply axial load to the bonded specimen step-by-step according to a preset stress gradient. After each load level is applied and reaches a stable state, acquire and record the corresponding ultrasonic secondary echo amplitude signal. The reflection coefficient R under the corresponding stress level was calculated, and the reflection coefficient-assembly stress calibration data are shown in Table 1. Table 1

[0059] Step 203, Establishment of the reflection coefficient-interface stiffness calibration model. Based on the physical relationship model between the ultrasonic reflection coefficient R and the interface stiffness K, a calibration model for the ultrasonic reflection coefficient R and the interface stiffness K is established; Step 204: Establishment of the assembly stress-interface stiffness calibration model. Using the known assembly stress applied in step 202 and the corresponding interface stiffness values ​​calculated in step 203, a quantitative relationship model of "assembly stress-interface stiffness" is established and calibrated through data fitting. ; Step 205: Assembly Stress Measurement. Apply an arbitrary stress of unknown magnitude to the specimen, measure its secondary echo amplitude signal and calculate the reflection coefficient, further solving for the current interface stiffness. Finally, substitute the calculated interface stiffness value into the relational model calibrated in Step 204 to inversely calculate the assembly stress value to be measured.

[0060] In step 202, the reflection coefficient R, the reflection coefficient Equal to reflected signal and reference signal The ratio between them is as follows:

[0061] The physical relationship model between the ultrasonic reflection coefficient R and the interface stiffness K in step 203 is as follows:

[0062] Where Z1 is the acoustic impedance of medium 1, Z2 is the acoustic impedance of medium 2, and K is the interface stiffness. , ( (where ω is the ultrasonic frequency) is the ultrasonic angular frequency.

[0063] Figure 3 A schematic block diagram of an ultrasonic testing device for assembly stress of a five-axis gantry milling and turning machine tool according to an embodiment of the present invention is shown.

[0064] like Figure 3 As shown, in a second aspect, embodiments of the present invention provide an ultrasonic testing device 30 for assembly stress of a five-axis gantry milling and turning composite machine tool, the device comprising: Acquisition module 31 is used to acquire ultrasonic reflected echo signals for the target assembly connection part, wherein the target assembly connection part is located on the five-axis gantry milling and turning composite machine tool. Calculation module 32 is used to calculate ultrasonic characteristic parameters characterizing the current state of the target assembly connection part based on the ultrasonic reflected echo signal; The stress inversion module 33 is used to input the ultrasonic characteristic parameters into a pre-established assembly stress calibration model to obtain the current assembly stress value of the target assembly connection part, wherein the assembly stress calibration model includes a three-level calibration model.

[0065] In one embodiment, optionally, the process of establishing the three-level calibration model includes: Establish the mapping relationship between the ultrasonic characteristic parameters and the equivalent stiffness of the assembly interface; Through experimental calibration, a quantitative relationship between the equivalent stiffness of the assembly interface and the assembly stress was established. By integrating the mapping relationship and the quantitative relationship, an assembly stress calibration model is formed that ranges from the ultrasonic characteristic parameters to the assembly stress.

[0066] In one embodiment, optionally, the ultrasonic feature system includes an ultrasonic reflection coefficient, and the ultrasonic reflected echo signal includes a reference reflection signal under stress-free conditions and an actually measured reflection signal; Based on the ultrasonic reflected echo signal, ultrasonic characteristic parameters characterizing the current state of the target assembly connection are calculated, including: The ultrasonic reflection coefficient is obtained by calculating the ratio of the first amplitude of the reference reflection signal under stress-free conditions to the second amplitude of the actual measured reflection signal.

[0067] In one embodiment, optionally, the ultrasonic reflection coefficient and the equivalent stiffness of the assembly interface satisfy an ultrasonic interface acoustic model:

[0068] Where R represents the ultrasonic reflection coefficient, Z1 and Z2 represent the acoustic impedance of the media on both sides of the assembly interface, ω represents the ultrasonic angular frequency, K represents the equivalent stiffness of the assembly interface, and i represents the imaginary unit.

[0069] In one embodiment, optionally, the quantitative relationship between the equivalent stiffness of the assembly interface and the assembly stress is calibrated by gradient stress loading experiments, and a continuous mapping model is established by curve fitting or machine learning.

[0070] In one embodiment, the target assembly connection part may optionally include at least one of the following: bed, column, spindle box, slide, guide rail mounting surface, and bolt fastening connection surface of a five-axis gantry milling and turning composite machine tool.

[0071] In one embodiment, optionally, the apparatus further includes: The update module is used to periodically collect measured stress data and corresponding ultrasonic characteristic parameters of the target assembly connection parts, and to perform online updates and iterative optimization of the assembly stress calibration model.

[0072] Thirdly, embodiments of the present invention provide a computer-readable storage medium storing computer-executable instructions, the computer-executable instructions being used to execute the assembly stress ultrasonic testing method for a five-axis gantry milling and turning composite machine tool as described in any one of the embodiments of the first aspect above.

[0073] Fourthly, embodiments of the present invention provide a computer device, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the assembly stress ultrasonic testing method for a five-axis gantry milling and turning composite machine tool as described in any one of the embodiments of the first aspect.

[0074] In the above technical solution, ultrasonic reflected echo signals are acquired for the target assembly connection part, wherein the target assembly connection part is located on the five-axis gantry milling and turning composite machine tool; based on the ultrasonic reflected echo signals, ultrasonic characteristic parameters characterizing the current state of the target assembly connection part are calculated; the ultrasonic characteristic parameters are input into a pre-established assembly stress calibration model to obtain the current assembly stress value of the target assembly connection part, wherein the assembly stress calibration model includes a three-level calibration model. In this invention, by acquiring ultrasonic reflected echo signals from the target assembly connection part of the five-axis gantry milling and turning composite machine tool, calculating the corresponding ultrasonic characteristic parameters, and inputting them into an assembly stress calibration model containing a three-level calibration model, the current assembly stress value of the assembly connection part can be directly, quickly, and quantitatively calculated. This achieves non-destructive testing of assembly stress without disassembling the machine tool or damaging the structure, effectively solving the problems of traditional assembly quality control methods being unable to perform online detection, quantitative evaluation, or real-time feedback and control. It significantly improves the efficiency and accuracy of machine tool assembly stress detection, providing reliable data support and technical assurance for assembly process optimization and assembly quality consistency control.

[0075] In summary, although this solution provides a preferred implementation method, those skilled in the art can make various equivalent substitutions for the specific implementation methods without departing from the overall technical concept of this solution, and all such substitutions should be considered to fall within the protection scope of this solution.

[0076] In one embodiment, a computer device is provided, which may be a server, and its internal structure diagram may be as follows: Figure 4As shown, the computer device includes a processor, memory, network interface, and database connected via a system bus. The processor provides computing and control capabilities. The memory includes non-volatile and / or volatile storage media and internal memory. The non-volatile storage media stores the operating system, computer programs, and database. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage media. The network interface is used to communicate with external clients via a network connection. When the computer program is executed by the processor, it implements the functions or steps of a method for measuring characteristic parameters of radio frequency signals on the server side.

[0077] In one embodiment, a computer device is provided, which may be a client, and its internal structure diagram may be as follows: Figure 5 As shown, the computer device includes a processor, memory, network interface, display screen, and input devices connected via a system bus. The processor provides computing and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage media. The network interface is used to communicate with an external server via a network connection. When executed by the processor, the computer program implements the client-side functions or steps of a method for measuring characteristic parameters of radio frequency signals.

[0078] In one embodiment, a computer device is provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the method for measuring characteristic parameters of the radio frequency signal described above.

[0079] It should be noted that the functions or steps that can be implemented by the computer-readable storage medium or computer device described above can be referred to the relevant descriptions in the foregoing method embodiments. To avoid repetition, they will not be described one by one here.

[0080] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0081] It should be understood that although the terms "first," "second," etc., may be used to describe the setting units in the embodiments of this application, these setting units should not be limited to these terms. These terms are only used to distinguish the setting units from each other. For example, without departing from the scope of the embodiments of this application, the first setting unit may also be referred to as the second setting unit, and similarly, the second setting unit may also be referred to as the first setting unit.

[0082] Depending on the context, the word "if" as used here can be interpreted as "when," "when," "in response to determination," or "in response to detection." Similarly, depending on the context, the phrase "if determination" or "if detection (of the stated condition or event)" can be interpreted as "when determination," "in response to determination," "when detection (of the stated condition or event)," or "in response to detection (of the stated condition or event)."

[0083] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0084] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or in a combination of hardware and software functional units.

[0085] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium. When executed, the computer program can include the processes of the embodiments of the above methods. Any references to memory, storage, databases, or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in a variety of forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), RAMbus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.

[0086] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A method for ultrasonic testing of assembly stress in a five-axis gantry milling and turning composite machine tool, characterized in that, The method includes: Acquire ultrasonic reflected echo signals for the target assembly connection part, wherein the target assembly connection part is located on the five-axis gantry milling and turning composite machine tool; Based on the ultrasonic reflected echo signal, ultrasonic characteristic parameters characterizing the current state of the target assembly connection part are calculated; The ultrasonic characteristic parameters are input into a pre-established assembly stress calibration model to obtain the current assembly stress value of the target assembly connection part. The assembly stress calibration model includes a three-level calibration model.

2. The method according to claim 1, characterized in that, The process of establishing the three-level calibration model includes: Establish the mapping relationship between the ultrasonic characteristic parameters and the equivalent stiffness of the assembly interface; Through experimental calibration, a quantitative relationship between the equivalent stiffness of the assembly interface and the assembly stress was established. By integrating the mapping relationship and the quantitative relationship, an assembly stress calibration model is formed that ranges from the ultrasonic characteristic parameters to the assembly stress.

3. The method according to claim 2, characterized in that, The ultrasonic feature system includes an ultrasonic reflection coefficient, and the ultrasonic reflected echo signal includes a reference reflection signal under stress-free conditions and an actual measured reflection signal. Based on the ultrasonic reflected echo signal, ultrasonic characteristic parameters characterizing the current state of the target assembly connection are calculated, including: The ultrasonic reflection coefficient is obtained by calculating the ratio of the first amplitude of the reference reflection signal under stress-free conditions to the second amplitude of the actual measured reflection signal.

4. The method according to claim 3, characterized in that, The ultrasonic reflection coefficient and the equivalent stiffness of the assembly interface satisfy the ultrasonic interface acoustic model: Where R represents the ultrasonic reflection coefficient, Z1 and Z2 represent the acoustic impedance of the media on both sides of the assembly interface, ω represents the ultrasonic angular frequency, K represents the equivalent stiffness of the assembly interface, and i represents the imaginary unit.

5. The method according to claim 2, characterized in that, The quantitative relationship between the equivalent stiffness of the assembly interface and the assembly stress is calibrated through gradient stress loading experiments, and a continuous mapping model is established by curve fitting or machine learning.

6. The method according to claim 1, characterized in that, The target assembly connection part includes at least one of the following: bed, column, spindle box, slide, guide rail mounting surface, and bolt fastening connection surface of the five-axis gantry milling and turning composite machine tool.

7. The method according to claim 1, characterized in that, The method further includes: The measured stress data and corresponding ultrasonic characteristic parameters of the target assembly connection parts are collected periodically, and the assembly stress calibration model is updated and iteratively optimized online.

8. An ultrasonic testing device for assembly stress of a five-axis gantry milling and turning composite machine tool, characterized in that, The device includes: The acquisition module is used to acquire ultrasonic reflected echo signals for the target assembly connection part, wherein the target assembly connection part is located on the five-axis gantry milling and turning composite machine tool. The calculation module is used to calculate ultrasonic characteristic parameters that characterize the current state of the target assembly connection part based on the ultrasonic reflected echo signal. The stress inversion module is used to input the ultrasonic characteristic parameters into a pre-established assembly stress calibration model to obtain the current assembly stress value of the target assembly connection part, wherein the assembly stress calibration model includes a three-level calibration model.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the method of any one of claims 1 to 7.

10. A computer-readable storage medium storing computer-executable instructions, characterized in that, The computer-executable instructions are used to perform the method as described in any one of claims 1 to 7.

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