Material fatigue test method and device

Abstract

The invention discloses a material fatigue test method and device. The method comprises the following steps: acquiring an equipment parameter of the fatigue testing machine, and acquiring a first control parameter for controlling a load controller of the fatigue testing machine; constructing a fatigue test reference model based on the equipment parameters and the first control parameters; the load controller and the amplitude compensation controller are used for controlling the fatigue testing machine to conduct fatigue testing on the target material, fatigue testing simulation is synchronously conducted on the target material on the basis of the fatigue testing reference model, and the amplitude compensation controller is used for controlling the fatigue testing machine to conduct fatigue testing on the target material every second preset period. Compensating the amplitude of the load control signal according to the output load amplitude of the fatigue testing machine; and adjusting the first control parameter based on the difference between the fatigue test result and the fatigue test simulation result every first preset period. The technical problem that in a high-frequency fatigue test, the amplitude of a response curve of a fatigue testing machine is attenuated, and the accuracy of the fatigue test is affected is solved.

Description

Technical Field

[0001] This application relates to the field of materials testing technology, and more specifically, to a method and apparatus for materials fatigue testing. Background Technology

[0002] Electro-hydraulic servo fatigue testing machines are widely used in materials mechanics testing, structural strength testing, and engineering material performance research. They employ a servo control system, using servo valves to control the movement of a hydraulic press, achieving precise position, speed, and force control. Currently, most commercially available electro-hydraulic servo fatigue testing machines use traditional PID (Proportional-Integral-Derivative) algorithms for closed-loop control. However, due to the high nonlinearity and parameter uncertainty of electro-hydraulic servo control systems, traditional PID algorithms are susceptible to the influence of mechanical structure and control cycle. During high-frequency fatigue testing, this can lead to time-varying parameters in the fatigue testing machine, causing a decrease in the amplitude of the response curve and affecting the accuracy of the material fatigue test.

[0003] There is currently no effective solution to the above problems. Summary of the Invention

[0004] This application provides a material fatigue testing method and apparatus to at least solve the technical problem that the amplitude of the response curve of the fatigue testing machine will decrease in high-frequency fatigue tests, affecting the accuracy of the fatigue test.

[0005] According to one aspect of the embodiments of this application, a material fatigue testing method is provided, comprising: acquiring equipment parameters of a fatigue testing machine and acquiring first control parameters of a load controller for controlling the fatigue testing machine, wherein the load controller is used to control the fatigue testing machine to output a load to a target material according to a preset load control signal; constructing a fatigue testing reference model based on the equipment parameters and the first control parameters; controlling the fatigue testing machine to perform fatigue testing on the target material using the load controller and an amplitude compensation controller, and synchronously performing fatigue testing simulation on the target material based on the fatigue testing reference model, wherein the amplitude compensation controller is used to compensate the amplitude of the load control signal according to the output load amplitude of the fatigue testing machine every second preset period; and adjusting the first control parameters based on the difference between the fatigue testing results and the fatigue testing simulation results every first preset period, wherein the first preset period is shorter than the second preset period.

[0006] Optionally, both the load controller and the amplitude compensation controller are PID controllers; the input of the amplitude compensation controller is the first amplitude of the preset first load control signal, the feedback is the second amplitude of the output load of the fatigue testing machine, and the output is the adjusted third amplitude; the input of the load controller is the second load control signal after adjusting the first load control signal based on the third amplitude, the feedback is the output load of the fatigue testing machine, and the output is the adjusted third load control signal; the input of the fatigue testing machine is the third load control signal.

[0007] Optionally, a fatigue test reference model is constructed based on equipment parameters and a first control parameter, including: constructing a first transfer function corresponding to the fatigue testing machine based on the equipment parameters; constructing a second transfer function corresponding to the load controller based on the first control parameter; and constructing a fatigue test reference model based on the first and second transfer functions.

[0008] Optionally, the fatigue testing machine includes a servo valve and a hydraulic press. The first transfer function includes a third transfer function corresponding to the servo valve and a fourth transfer function corresponding to the hydraulic press. The first transfer function corresponding to the fatigue testing machine is constructed based on the equipment parameters, including: constructing the third transfer function based on the parameters of the servo valve as follows: In the formula, s represents the Laplace operator. This represents the third transfer function. This indicates the flow gain of the servo valve. This indicates the natural frequency of the servo valve. This represents the damping ratio of the servo valve; the fourth transfer function is constructed based on the parameters of the hydraulic press as follows: In the formula, This represents the fourth transfer function. This represents the flow gain of the hydraulic press when the spool valve is in the zero position, and A represents the effective piston area of ​​the hydraulic press. This indicates the natural frequency of the hydraulic press. This indicates the damping ratio of the hydraulic press.

[0009] Optionally, the first control parameters include: proportional control parameters, integral control parameters, and derivative control parameters. The second transfer function corresponding to the load controller is constructed based on the first control parameters, including: constructing the second transfer function of the load controller in the continuous domain based on the first control parameters as follows: In the formula, This represents the second transfer function. This represents the proportional control parameter. Indicates integral control parameters. Represents the differential control parameters. This indicates the first preset cycle.

[0010] Optionally, a fatigue test reference model is constructed based on the first transfer function and the second transfer function, including: constructing a fatigue test reference model based on the third transfer function, the fourth transfer function, and the second transfer function as follows: In the formula, This represents the fatigue test reference model.

[0011] Optionally, the first control parameter is adjusted based on the difference between the fatigue test results and the fatigue test simulation results, including: determining the difference between the fatigue test results and the fatigue test simulation results as follows: In the formula, This represents the output load of the fatigue test at time t. This represents the output load of the fatigue test simulation at time t. The difference between the fatigue test results and the fatigue test simulation results at time t is represented; the performance index function is determined as follows: In the formula, Represents the variable to be solved. The performance index function is defined by substituting the proportional control parameter, integral control parameter, and derivative control parameter from the first control parameter into the performance index function. The gradient of the performance index function is determined, and the adjustment step size of the proportional control parameter, integral control parameter and derivative control parameter is solved by gradient descent method; the proportional control parameter, integral control parameter and derivative control parameter are adjusted according to each adjustment step size.

[0012] According to another aspect of the embodiments of this application, a material fatigue testing device is also provided, comprising: an acquisition module, configured to acquire equipment parameters of a fatigue testing machine and acquire first control parameters of a load controller for controlling the fatigue testing machine, wherein the load controller is configured to control the fatigue testing machine to output load to a target material according to a preset load control signal; a modeling module, configured to construct a fatigue testing reference model based on the equipment parameters and the first control parameters; a testing module, configured to control the fatigue testing machine to perform fatigue testing on the target material using the load controller and an amplitude compensation controller, and to synchronously perform fatigue testing simulation on the target material based on the fatigue testing reference model, wherein the amplitude compensation controller is configured to compensate the amplitude of the load control signal according to the output load amplitude of the fatigue testing machine every second preset period; and an adjustment module, configured to adjust the first control parameters based on the difference between the fatigue testing results and the fatigue testing simulation results every second preset period, wherein the second preset period is shorter than the first preset period.

[0013] According to another aspect of the embodiments of this application, a computer program product is also provided, the computer program product comprising: a computer program, wherein the computer program, when executed by a processor, implements the above-described material fatigue testing method.

[0014] According to another aspect of the embodiments of this application, an electronic device is also provided, the electronic device including: a memory and a processor, wherein the memory stores a computer program, and the processor is configured to execute the above-described material fatigue testing method through the computer program.

[0015] In this embodiment, a load controller and an amplitude compensation controller are primarily used to control a fatigue testing machine for fatigue testing. The load controller ensures that the fatigue testing machine applies load to the target material according to a preset load control signal, while the amplitude compensation controller periodically compensates for the amplitude of the control signal based on the actual output load amplitude of the fatigue testing machine. This dual-loop control mechanism prevents amplitude attenuation caused by mechanical system wear, enhances the stability of the fatigue testing machine's output amplitude, and improves the accuracy of material fatigue testing. Furthermore, a fatigue testing reference model is constructed based on the equipment parameters of the fatigue testing machine and the first control parameters of the load controller. This model accurately simulates the working state of the fatigue testing machine, providing a reference for subsequent control parameter optimization. Adjusting the control parameters of the fatigue testing machine through model simulation test results allows for precise control of the load output in high-frequency fatigue tests, improving the robustness of the fatigue test. This solution effectively solves the technical problem that the amplitude of the fatigue testing machine's response curve attenuates in high-frequency fatigue tests, affecting the accuracy of the fatigue test. Attached Figure Description

[0016] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0017] Figure 1 This is a schematic flowchart of an optional material fatigue testing method according to an embodiment of this application;

[0018] Figure 2 This is a schematic diagram of the control architecture of an optional fatigue testing machine according to an embodiment of this application;

[0019] Figure 3 This is a schematic diagram of an optional model reference adaptive control mechanism according to an embodiment of this application;

[0020] Figure 4 This is a schematic diagram of an optional material fatigue testing device according to an embodiment of this application;

[0021] Figure 5 This is a schematic diagram of the structure of an optional electronic device according to an embodiment of this application. Detailed Implementation

[0022] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0023] It should be noted that the terms "first," "second," etc., used in the specification, claims, and drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0024] To better understand the embodiments of this application, the following is a translation and explanation of some nouns or terms that appear in the description of the embodiments of this application:

[0025] A fatigue testing machine is a testing device specifically designed to evaluate the durability and fatigue performance of materials, parts, or structures under repeated or cyclic loads. It simulates various cyclic loads (such as tension, compression, bending, and torsion) that materials may encounter in practical applications, continuously applying loads to the specimen until cracks are observed, thus obtaining the fatigue limit or fatigue life of the material at a specific load frequency and amplitude. Generally, fatigue testing machines can be classified into various types based on load type and technical characteristics, such as electro-hydraulic servo fatigue testing machines, electromagnetic vibrator fatigue testing machines, pneumatic fatigue testing machines, and mechanical fatigue testing machines. This application's embodiments primarily use an electro-hydraulic servo fatigue testing machine as an example for illustration.

[0026] Transfer function: an important concept in control system engineering and signal processing, used to describe the mathematical relationship between the input and output of a linear time-invariant system. It is usually expressed as a complex frequency s, which is convenient for analyzing and designing the transfer behavior of control systems.

[0027] PID control: Proportional control can linearly adjust the controller output based on the current error (i.e., the difference between the set value and the actual value) to quickly respond and reduce the error; Integral control can gradually accumulate the error by calculating the integral of the error over time to adjust the controller output to eliminate static error; Derivative control can adjust the controller output based on the rate of change of the error to predict and suppress the change of the error.

[0028] Example 1

[0029] According to an embodiment of this application, a material fatigue testing method is provided. It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. Furthermore, although a logical order is shown in the flowchart, in some cases, the steps shown or described may be executed in a different order than that shown here.

[0030] Figure 1 This is a schematic flowchart of a material fatigue testing method provided in an embodiment of this application, as shown below. Figure 1 As shown, the method includes the following steps:

[0031] Step S102: Obtain the equipment parameters of the fatigue testing machine and obtain the first control parameters of the load controller used to control the fatigue testing machine. The load controller is used to control the fatigue testing machine to output load to the target material according to the preset load control signal.

[0032] Step S104: Construct a fatigue test reference model based on equipment parameters and first control parameters;

[0033] Step S106: The load controller and amplitude compensation controller are used to control the fatigue testing machine to perform fatigue testing on the target material, and fatigue testing simulation is performed on the target material simultaneously based on the fatigue testing reference model. The amplitude compensation controller is used to compensate the amplitude of the load control signal according to the output load amplitude of the fatigue testing machine every second preset cycle.

[0034] Step S108: After each first preset cycle, adjust the first control parameter based on the difference between the fatigue test results and the fatigue test simulation results, wherein the first preset cycle is shorter than the second preset cycle.

[0035] The following section explains each step of the material fatigue testing method in conjunction with the specific implementation process.

[0036] Typically, to control the fatigue testing machine to output load to the test material according to a preset load value, the control system of the fatigue testing machine includes a load controller. This controller continuously monitors parameters such as the actual load value, actuator displacement, and test frequency to correct deviations between the load output value and the preset value, ensuring the accuracy of the fatigue test. However, due to the complex mechanical structure of the fatigue testing machine, it is prone to linear time-varying problems in high-frequency vibration experiments, leading to overshoot of the load controller and attenuation of its response curve amplitude, thus affecting the accuracy of the fatigue test.

[0037] To address the aforementioned issues, this application embodiment improves the overall control architecture of the fatigue testing machine by introducing an amplitude compensation controller in addition to the load controller, in order to compensate for and correct the amplitude fluctuation of the output load of the fatigue testing machine.

[0038] As an optional implementation, both the load controller and the amplitude compensation controller in this embodiment are PID controllers. The amplitude compensation controller receives a first amplitude of a preset first load control signal as input, receives a second amplitude of the output load of the fatigue testing machine as feedback, and outputs an adjusted third amplitude. The load controller receives a second load control signal adjusted based on the third amplitude of the first load control signal, receives a second amplitude of the output load of the fatigue testing machine as feedback, and outputs an adjusted third load control signal. The fatigue testing machine receives the third load control signal as input. Figure 2 This is a schematic diagram of the overall control architecture of an optional fatigue testing machine.

[0039] Optionally, the first load control signal mentioned above can be a sine curve, and its formula is:

[0040]

[0041] In the formula, This represents the signal value of the first load control signal at time t. This represents the first amplitude of the first load control signal, and f represents the frequency of the first load control signal.

[0042] Based on this, the formula corresponding to the amplitude compensation controller can be determined as follows:

[0043]

[0044] In the formula, This represents the third amplitude output by the amplitude compensation controller at the k-th time step. , , These represent the proportional control parameters, integral control parameters, and derivative control parameters of the amplitude compensation controller, respectively. This indicates amplitude error feedback. This represents the second amplitude of the output load of the fatigue testing machine at the k-th time step.

[0045] Since the input of the amplitude compensation controller is related to the amplitude of the first load control signal and the output load, and acquiring the amplitude of the output load requires at least a quarter cycle, the control cycle of the amplitude compensation controller can be set to [value missing]. .

[0046] The first load control signal can then be adjusted using the following formula:

[0047]

[0048] In the formula, This represents the signal value of the adjusted second load control signal at the k-th time step. This represents the signal value of the first load control signal at the k-th time step.

[0049] Based on this, the formula corresponding to the load controller can be determined as follows:

[0050]

[0051] In the formula, This represents the signal value of the third load control signal output by the load controller at the k-th time step. , , These represent the proportional control parameters, integral control parameters, and derivative control parameters of the load controller, respectively. This indicates load error feedback. This represents the output load value of the fatigue testing machine at the k-th time step.

[0052] The control cycle of the load controller is relatively short, for example, it can be set to 0.0001s.

[0053] This application embodiment divides the control architecture of the fatigue testing machine into two layers: inner loop load control and outer loop amplitude compensation control. Load control can quickly respond to changes in output load and correct deviations in output load more rapidly. Amplitude compensation control focuses on the overall test objective to maintain the stability of the output load amplitude. This control architecture effectively solves the problem of output load amplitude attenuation caused by material fatigue, mechanical wear, temperature changes, etc., and can significantly improve the accuracy and repeatability of material fatigue testing.

[0054] Furthermore, considering the high nonlinearity of the fatigue testing machine and the parameter uncertainties caused by different experimental materials, this application also proposes an MRAC (Model Reference Adaptive Control) mechanism. This mechanism establishes a fatigue testing reference model to guide the setting of controller parameters during fatigue testing. The fatigue testing reference model is an idealized system control model that receives the same desired output load as the actual fatigue testing machine and outputs a response trajectory, representing the ideal control template for obtaining the desired output load. This trajectory guides the parameter design of the fatigue testing machine's controller. MRAC aims to continuously adjust the controller parameters to make the system output more consistent with the output of the reference model. This control method is particularly suitable for situations involving unknown, time-varying, or complex systems.

[0055] As an optional implementation method, a fatigue test reference model can be constructed through the following steps S1-S3.

[0056] S1, obtain the equipment parameters of the fatigue testing machine, and construct the first transfer function corresponding to the fatigue testing machine based on the equipment parameters.

[0057] Since the electro-hydraulic servo fatigue testing machine mainly includes a servo valve as the controlled object and a hydraulic press as the actuator, the third transfer function corresponding to the servo valve and the fourth transfer function corresponding to the hydraulic press can be established respectively. To this end, the natural frequency, damping ratio and flow gain of the servo valve, as well as the effective piston area, natural frequency and damping ratio of the hydraulic press and other relevant equipment parameters can be obtained first.

[0058] The third transfer function is a mathematical model describing the dynamic relationship between the input and output of the servo valve. Its form depends on the switching characteristics of the servo valve, and therefore can be expressed as a transfer function of a second-order system. Optionally, the third transfer function can be constructed based on the parameters of the servo valve as follows:

[0059]

[0060] In the formula, s represents the Laplace operator; Indicates the third transfer function; It is the flow gain of the servo valve, representing the proportion of flow change caused by a unit change in control signal; The natural frequency of the servo valve reflects the inherent characteristics of its internal mechanical structure and determines its response speed. It is the damping ratio of the servo valve, which describes the servo valve's ability to dissipate internal energy and suppress oscillations, thus affecting the stability of the servo valve.

[0061] The fourth transfer function is a mathematical model describing the dynamic relationship between the input servo valve outlet flow rate and the output piston displacement in a hydraulic press. Its form depends on the dynamic characteristics of the hydraulic press, such as elasticity, damping, and friction; therefore, it can be expressed as a transfer function of a third-order system. Optionally, the fourth transfer function can be constructed based on the parameters of the hydraulic press as follows:

[0062]

[0063] In the formula, Indicates the fourth transfer function; This represents the flow gain of the hydraulic press when the spool valve is in the zero position, i.e., the flow rate through the spool valve per unit displacement; A represents the effective piston area of ​​the hydraulic press, which determines the magnitude of the force acting on the piston. It represents the natural frequency of the hydraulic press, reflecting the inherent characteristics of the internal mechanical structure of the hydraulic press; The damping ratio indicates the hydraulic press's mechanical characteristics, such as the viscous resistance of the hydraulic oil and the elasticity of the seals.

[0064] In a fatigue testing machine, the entire process from control signal input to final load output is essentially a cascade of the dynamic responses of the servo valve and the hydraulic press. Therefore, after obtaining the third transfer function corresponding to the servo valve and the fourth transfer function corresponding to the hydraulic press, the first transfer function of the fatigue testing machine can be constructed by cascading these two transfer functions.

[0065]

[0066] In the formula, This represents the first transfer function of the fatigue testing machine.

[0067] The first transfer function constructed through the above steps can accurately mathematically describe the output characteristics of the servo valve and the hydraulic press when the control signal is input. The above modeling method takes into account factors such as the frequency response, gain and damping ratio of the two, making the reference model closer to the actual physical system and more accurately predicting the system response under various input conditions.

[0068] S2, obtain the first control parameters of the load controller, and construct the second transfer function corresponding to the load controller based on the first control parameters.

[0069] The first control parameters mainly include the proportional control parameters, integral control parameters, and derivative control parameters initially set for the load controller.

[0070] Based on the above analysis of the load controller's input and output, its transfer function in the discrete domain can be constructed as follows:

[0071]

[0072] In the formula, The variable z represents the discrete-domain transfer function; z represents the discrete-domain variable. , , These represent the proportional control parameter, integral control parameter, and derivative control parameter of the load controller, respectively, and their initial values ​​correspond to the first control parameter mentioned above. This indicates load error feedback. This indicates the control cycle of the load controller.

[0073] Then, the bilinear transformation can be used to convert the discrete-domain transfer function into a second transfer function in the continuous domain, as follows:

[0074]

[0075] In the formula, This represents the second transfer function.

[0076] The second transfer function of the load controller constructed through the above steps can generate an ideal control signal. The control parameters of this control signal provide a reference for adjusting the control parameters of the load controller in the subsequent fatigue testing machine.

[0077] S3. Construct a fatigue test reference model based on the first transfer function and the second transfer function.

[0078] Alternatively, a fatigue test reference model can be constructed by calculating the open-loop transfer functions of the third, fourth, and second transfer functions, as follows:

[0079]

[0080] In the formula, This represents the fatigue test reference model.

[0081] It should be noted that, since the control cycle of the amplitude compensation controller is much longer than that of the load controller, the amplitude compensation controller only participates in actual control once when the control parameters of the load controller are adjusted multiple times. In other words, the influence of the amplitude compensation controller on the control parameter adjustment of the load controller can be ignored. In order to avoid the final modeling order being too high and difficult to calculate, this application only models the load controller and the fatigue testing machine, and does not model the amplitude compensation controller.

[0082] Optionally, after the fatigue test reference model is constructed, the fatigue testing machine can be controlled to perform fatigue tests on the target material using a load controller and an amplitude compensation controller based on the model reference adaptive control mechanism. At the same time, fatigue test simulations of the target material can be performed synchronously based on the fatigue test reference model, and the first control parameter can be adjusted based on the difference between the fatigue test results and the fatigue test simulation results. Figure 3An optional model reference adaptive control flow is shown.

[0083] Specifically, the differences between the fatigue test results and the fatigue test simulation results can be determined as follows:

[0084]

[0085] In the formula, This represents the output load of the fatigue test at time t. This represents the output load of the fatigue test simulation at time t. The difference between the fatigue test results and the fatigue test simulation results at time t reflects the degree of deviation between the actual test and the ideal test model.

[0086] In the actual fatigue testing process, The error value can be positive or negative. However, from the perspective of objective optimization, the key to minimizing the error magnitude lies in reducing the absolute magnitude of the difference between the fatigue test results and the fatigue test simulation results, regardless of their positive or negative direction. Furthermore, the core of the optimization algorithm is to find the minimum point of the function value (usually set to 0) to achieve the optimal solution. If the error value is sometimes positive and sometimes negative, the optimization algorithm may lose its way amidst these changes and fail to effectively converge to the state of minimum error. To avoid this problem, this application constructs a performance index function. By substituting the proportional control parameter, integral control parameter, and derivative control parameter from the first control parameter into the performance index function and determining the gradient of the performance index function, the adjustment step size of each of the proportional control parameter, integral control parameter, and derivative control parameter can be solved using the gradient descent method.

[0087] Specifically, the performance metric function can be constructed as follows:

[0088]

[0089] In the formula, Represents the variable to be solved. This represents a performance metric function.

[0090] The gradient of the performance index function is determined as follows:

[0091]

[0092] In the formula, This is the adaptive gain coefficient.

[0093] Substitute the proportional control parameter, integral control parameter, and derivative control parameter from the first control parameter into the above equation:

[0094]

[0095]

[0096]

[0097] In the formula, , and These represent the adaptive gain coefficients corresponding to the proportional control parameter, integral control parameter, and derivative control parameter, respectively.

[0098] Solving the above equation, we can obtain the adjustment step sizes for the proportional control parameter, integral control parameter, and derivative control parameter as follows:

[0099]

[0100]

[0101]

[0102] In the formula, , , These represent the adjustment step sizes for the proportional control parameter, integral control parameter, and derivative control parameter, respectively. This indicates the preset magnification factor; , ..., These represent the coefficients of the denominator polynomial of the performance index function, derived from the coefficients calculated from the open-loop transfer function, including parameters related to system stability and response speed.

[0103] Finally, by adjusting the proportional control parameters, integral control parameters, and derivative control parameters according to each adjustment step size, the performance index function can be minimized, the nonlinear oscillations and steady-state errors caused by mechanical factors such as static friction of the servo valve and dead zone in the fatigue testing machine can be reduced, and the stability and accuracy of the system can be improved.

[0104] In this embodiment, a load controller and an amplitude compensation controller are primarily used to control a fatigue testing machine for fatigue testing. The load controller ensures that the fatigue testing machine applies load to the target material according to a preset load control signal, while the amplitude compensation controller periodically compensates for the amplitude of the control signal based on the actual output load amplitude of the fatigue testing machine. This dual-loop control mechanism prevents amplitude attenuation caused by mechanical system wear, enhances the stability of the fatigue testing machine's output amplitude, and improves the accuracy of material fatigue testing. Furthermore, a fatigue testing reference model is constructed based on the equipment parameters of the fatigue testing machine and the first control parameters of the load controller. This model accurately simulates the working state of the fatigue testing machine, providing a reference for subsequent control parameter optimization. Adjusting the control parameters of the fatigue testing machine through model simulation test results allows for precise control of the load output in high-frequency fatigue tests, improving the robustness of the fatigue test. This solution effectively solves the technical problem that the amplitude of the fatigue testing machine's response curve attenuates in high-frequency fatigue tests, affecting the accuracy of the fatigue test.

[0105] Example 2

[0106] According to an embodiment of this application, a material fatigue testing apparatus for implementing the material fatigue testing method in Embodiment 1 is also provided, such as... Figure 4 As shown, the material fatigue testing device includes at least: an acquisition module 41, a modeling module 42, a testing module 43, and an adjustment module 44, wherein:

[0107] The acquisition module 41 is used to acquire the equipment parameters of the fatigue testing machine and the first control parameters of the load controller used to control the fatigue testing machine. The load controller is used to control the fatigue testing machine to output load to the target material according to the preset load control signal.

[0108] Modeling module 42 is used to construct a fatigue test reference model based on equipment parameters and first control parameters;

[0109] Test module 43 is used to control the fatigue testing machine to perform fatigue testing on the target material using a load controller and an amplitude compensation controller, and to perform fatigue testing simulation on the target material synchronously based on a fatigue testing reference model. The amplitude compensation controller is used to compensate the amplitude of the load control signal according to the output load amplitude of the fatigue testing machine every second preset cycle.

[0110] The adjustment module 44 is used to adjust the first control parameter based on the difference between the fatigue test results and the fatigue test simulation results every second preset period, wherein the second preset period is shorter than the first preset period.

[0111] The following section explains the functions of each module of the material fatigue testing device in conjunction with the specific implementation process.

[0112] As an optional implementation, both the load controller and the amplitude compensation controller are PID controllers; the input of the amplitude compensation controller is the first amplitude of the preset first load control signal, the feedback is the second amplitude of the output load of the fatigue testing machine, and the output is the adjusted third amplitude; the input of the load controller is the second load control signal after adjusting the first load control signal based on the third amplitude, the feedback is the output load of the fatigue testing machine, and the output is the adjusted third load control signal; the input of the fatigue testing machine is the third load control signal.

[0113] Optionally, the modeling module can construct a fatigue test reference model based on the following methods: constructing a first transfer function corresponding to the fatigue testing machine based on the equipment parameters; constructing a second transfer function corresponding to the load controller based on the first control parameters; and constructing a fatigue test reference model based on the first and second transfer functions.

[0114] The fatigue testing machine includes a servo valve and a hydraulic press. The first transfer function includes a third transfer function corresponding to the servo valve and a fourth transfer function corresponding to the hydraulic press. When constructing the first transfer function corresponding to the fatigue testing machine based on the equipment parameters, the modeling module can do so in the following way: The third transfer function is constructed based on the parameters of the servo valve as follows: In the formula, s represents the Laplace operator. This represents the third transfer function. This indicates the flow gain of the servo valve. This indicates the natural frequency of the servo valve. This represents the damping ratio of the servo valve; the fourth transfer function is constructed based on the parameters of the hydraulic press as follows: In the formula, This represents the fourth transfer function. This represents the flow gain of the hydraulic press when the spool valve is in the zero position, and A represents the effective piston area of ​​the hydraulic press. This indicates the natural frequency of the hydraulic press. This indicates the damping ratio of the hydraulic press.

[0115] Optionally, the first control parameters include: proportional control parameters, integral control parameters, and derivative control parameters. When the modeling module constructs the second transfer function corresponding to the load controller based on the first control parameters, it can do so in the following manner: The second transfer function of the load controller in the continuous domain is constructed based on the first control parameters as follows: In the formula, This represents the second transfer function. This represents the proportional control parameter. Indicates integral control parameters. Represents the differential control parameters. This indicates the first preset cycle.

[0116] Finally, the modeling module constructs the fatigue test reference model based on the third transfer function, the fourth transfer function, and the second transfer function as follows: In the formula, This represents the fatigue test reference model.

[0117] As an optional implementation, the adjustment module can adjust the first control parameter in the following way: The difference between the fatigue test results and the fatigue test simulation results is determined as follows: In the formula, This represents the output load of the fatigue test at time t. This represents the output load of the fatigue test simulation at time t. The difference between the fatigue test results and the fatigue test simulation results at time t is represented; the performance index function is determined as follows: In the formula, Represents the variable to be solved. The performance index function is defined by substituting the proportional control parameter, integral control parameter, and derivative control parameter from the first control parameter into the performance index function. The gradient of the performance index function is determined, and the adjustment step size of the proportional control parameter, integral control parameter and derivative control parameter is solved by gradient descent method; the proportional control parameter, integral control parameter and derivative control parameter are adjusted according to each adjustment step size.

[0118] It should be noted that each module in the material fatigue testing device in this embodiment corresponds one-to-one with each implementation step of the material fatigue testing method in Embodiment 1. Since Embodiment 1 has been described in detail, some details not shown in this embodiment can be referred to Embodiment 1, and will not be elaborated further here.

[0119] Example 3

[0120] According to an embodiment of this application, a computer program product is also provided, which includes a computer program, wherein when the computer program is executed by a processor, it implements the material fatigue testing method in Embodiment 1.

[0121] According to an embodiment of this application, a non-volatile storage medium is also provided, which includes a stored computer program, wherein the device containing the non-volatile storage medium executes the material fatigue testing method in Embodiment 1 by running the computer program.

[0122] According to an embodiment of this application, a processor is also provided for running a computer program, wherein the computer program executes the material fatigue testing method in Embodiment 1 during runtime.

[0123] According to an embodiment of this application, an electronic device is also provided, comprising: a memory and a processor, wherein the memory stores a computer program, and the processor is configured to execute the material fatigue testing method of Embodiment 1 through the computer program.

[0124] Specifically, the computer program executes the following steps during runtime: acquiring the equipment parameters of the fatigue testing machine and acquiring the first control parameters of the load controller used to control the fatigue testing machine, wherein the load controller is used to control the fatigue testing machine to output load to the target material according to a preset load control signal; constructing a fatigue test reference model based on the equipment parameters and the first control parameters; using the load controller and amplitude compensation controller to control the fatigue testing machine to perform fatigue testing on the target material, and synchronously performing fatigue test simulation on the target material based on the fatigue test reference model, wherein the amplitude compensation controller is used to compensate the amplitude of the load control signal according to the output load amplitude of the fatigue testing machine every second preset period; adjusting the first control parameters based on the difference between the fatigue test results and the fatigue test simulation results every first preset period, wherein the first preset period is shorter than the second preset period.

[0125] As an alternative implementation, the above-mentioned electronic device may exist in the form of a mobile terminal, a computer terminal, or a similar computing device. Figure 5 A hardware block diagram of an electronic device for implementing a material fatigue testing method is shown. Figure 5 As shown, the electronic device 50 may include one or more processors 502 (shown as 502a, 502b, ..., 502n in the figure) 502 (processor 502 may include, but is not limited to, a microprocessor MCU or a programmable logic device FPGA, etc.), a memory 504 for storing data, and a transmission device 506 for communication functions. In addition, it may also include: a display, an input / output interface (I / O interface), a universal serial bus (USB) port (which may be included as one of the ports of a BUS bus), a network interface, a power supply, and / or a camera. Those skilled in the art will understand that... Figure 5 The structure shown is for illustrative purposes only and does not limit the structure of the electronic device described above. For example, electronic device 50 may also include... Figure 5 The more or fewer components shown, or having the same Figure 5 The different configurations shown.

[0126] It should be noted that the aforementioned one or more processors 502 and / or other data processing circuits are generally referred to herein as "data processing circuits". These data processing circuits may be embodied, in whole or in part, in software, hardware, firmware, or any other combination thereof. Furthermore, the data processing circuits may be a single, independent processing module, or may be integrated, in whole or in part, into any other element of the electronic device 50. As involved in the embodiments of this application, the data processing circuits serve as a processor control mechanism (e.g., selection of a variable resistor termination path connected to an interface).

[0127] The memory 504 can be used to store software programs and modules of application software, such as the program instructions / data storage device corresponding to the material fatigue testing method in this embodiment. The processor 502 executes various functional applications and data processing by running the software programs and modules stored in the memory 504, thereby implementing the aforementioned application vulnerability detection method. The memory 504 may include high-speed random access memory, and may also include non-volatile memory, such as one or more magnetic storage devices, flash memory, or other non-volatile solid-state memory. In some instances, the memory 504 may further include memory remotely located relative to the processor 502, and these remote memories can be connected to the electronic device 50 via a network. Examples of such networks include, but are not limited to, the Internet, corporate intranets, local area networks, mobile communication networks, and combinations thereof.

[0128] The transmission device 506 is used to receive or send data via a network. Specific examples of the network described above may include a wireless network provided by the communication provider of the electronic device 50. In one example, the transmission device 506 includes a Network Interface Controller (NIC), which can connect to other network devices via a base station to communicate with the Internet. In another example, the transmission device 506 may be a Radio Frequency (RF) module, used for wireless communication with the Internet.

[0129] The display can be, for example, a touchscreen liquid crystal display (LCD), which allows the user to interact with the user interface of the electronic device 50.

[0130] The sequence numbers of the above embodiments are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0131] In the above embodiments of this application, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0132] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. The device embodiments described above are merely illustrative; for example, the division of units can be 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 displayed or discussed mutual couplings, direct couplings, or communication connections may be through some interfaces; indirect couplings or communication connections between units or modules may be electrical or other forms.

[0133] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0134] 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 as a software functional unit.

[0135] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as a USB flash drive, read-only memory (ROM), random access memory (RAM), portable hard drive, magnetic disk, or optical disk.

[0136] The above are merely preferred embodiments of this application. It should be noted that those skilled in the art can make several improvements and modifications without departing from the principles of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A method for testing material fatigue, characterized in that, include: The equipment parameters of the fatigue testing machine are obtained, and the first control parameters of the load controller used to control the fatigue testing machine are obtained, wherein the load controller is used to control the fatigue testing machine to output load to the target material according to the preset load control signal; A fatigue test reference model is constructed based on the equipment parameters and the first control parameters; The load controller and amplitude compensation controller are used to control the fatigue testing machine to perform fatigue testing on the target material, and fatigue testing simulation is performed on the target material synchronously based on the fatigue testing reference model. The amplitude compensation controller is used to compensate the amplitude of the load control signal according to the output load amplitude of the fatigue testing machine every second preset cycle. After each first preset period, the first control parameter is adjusted based on the difference between the fatigue test results and the fatigue test simulation results, wherein the first preset period is shorter than the second preset period.

2. The method according to claim 1, characterized in that, Both the load controller and the amplitude compensation controller are proportional-integral-derivative (PID) controllers. The amplitude compensation controller is input to the first amplitude of the preset first load control signal, fed back to the second amplitude of the output load of the fatigue testing machine, and outputs the adjusted third amplitude. The load controller receives a second load control signal after adjusting the first load control signal based on the third amplitude, receives feedback as the output load of the fatigue testing machine, and outputs the adjusted third load control signal. The input to the fatigue testing machine is the third load control signal.

3. The method according to claim 1, characterized in that, A fatigue test reference model is constructed based on the equipment parameters and the first control parameters, including: Construct the first transfer function corresponding to the fatigue testing machine based on the equipment parameters; The second transfer function corresponding to the load controller is constructed based on the first control parameters; The fatigue test reference model is constructed based on the first transfer function and the second transfer function.

4. The method according to claim 3, characterized in that, The fatigue testing machine includes a servo valve and a hydraulic press. The first transfer function includes a third transfer function corresponding to the servo valve and a fourth transfer function corresponding to the hydraulic press. The first transfer function corresponding to the fatigue testing machine is constructed based on the equipment parameters, including: Based on the parameters of the servo valve, the third transfer function is constructed as follows: In the formula, s represents the Laplace operator. This represents the third transfer function. This indicates the flow gain of the servo valve. This indicates the inherent frequency of the servo valve. This indicates the damping ratio of the servo valve; Based on the parameters of the hydraulic press, the fourth transfer function is constructed as follows: In the formula, This represents the fourth transfer function. This represents the flow gain of the hydraulic press when the spool valve is in the zero position, and A represents the effective piston area of ​​the hydraulic press. This represents the natural frequency of the hydraulic press. This indicates the damping ratio of the hydraulic press.

5. The method according to claim 4, characterized in that, The first control parameters include: proportional control parameters, integral control parameters, and derivative control parameters. Based on the first control parameters, a second transfer function corresponding to the load controller is constructed, including: Based on the first control parameters, the second transfer function of the load controller in the continuous domain is constructed as follows: In the formula, This represents the second transfer function. This refers to the proportional control parameter. This represents the integral control parameter. This represents the differential control parameter. This indicates the first preset period.

6. The method according to claim 5, characterized in that, The fatigue test reference model is constructed based on the first transfer function and the second transfer function, including: The fatigue test reference model is constructed based on the third transfer function, the fourth transfer function, and the second transfer function as follows: In the formula, This refers to the fatigue test reference model.

7. The method according to claim 1, characterized in that, Adjusting the first control parameter based on the difference between fatigue test results and fatigue test simulation results includes: The differences between the fatigue test results and the fatigue test simulation results are determined as follows: In the formula, This represents the output load of the fatigue test at time t. This represents the output load of the fatigue test simulation at time t. This represents the difference between the fatigue test results and the fatigue test simulation results at time t; The performance index function is determined as follows: In the formula, Represents the variable to be solved. Represents the performance index function; Substitute the proportional control parameter, integral control parameter, and derivative control parameter from the first control parameter into the performance index function, respectively. And determine the gradient of the performance index function, and solve for the adjustment step size of the proportional control parameter, the integral control parameter and the derivative control parameter by gradient descent method; The proportional control parameter, the integral control parameter, and the derivative control parameter are adjusted according to each of the aforementioned adjustment step sizes.

8. A material fatigue testing device, characterized in that, include: The acquisition module is used to acquire the equipment parameters of the fatigue testing machine and the first control parameters of the load controller for controlling the fatigue testing machine, wherein the load controller is used to control the fatigue testing machine to output load to the target material according to a preset load control signal; The modeling module is used to construct a fatigue test reference model based on the equipment parameters and the first control parameters; The testing module is used to control the fatigue testing machine to perform fatigue testing on the target material using the load controller and amplitude compensation controller, and to synchronously perform fatigue testing simulation on the target material based on the fatigue testing reference model. The amplitude compensation controller is used to compensate the amplitude of the load control signal according to the output load amplitude of the fatigue testing machine every second preset cycle. An adjustment module is used to adjust the first control parameter based on the difference between the fatigue test results and the fatigue test simulation results every second preset period, wherein the second preset period is shorter than the first preset period.

9. A computer program product, characterized in that, include: A computer program, wherein when executed by a processor, the computer program implements the material fatigue testing method according to any one of claims 1 to 7.

10. An electronic device, characterized in that, include: A memory and a processor, wherein the memory stores a computer program, and the processor is configured to execute the material fatigue testing method according to any one of claims 1 to 7 via the computer program.

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