Chaotic detection method and device for early fault signal of transmission gear and medium

Abstract

The invention discloses a chaos detection method and device for an early fault signal of a transmission gear and a medium, and the method comprises the steps: constructing a chaos detection system model, and constructing the chaos detection system model based on a Duffing equation; adjusting model parameters of the chaos detection system model, so that the periodic excitation amplitude of the chaos detection system model is kept at 15-20 times of the noise amplitude of the to-be-detected signal; determining a threshold value of the periodic excitation amplitude; enabling the chaos detection system model to be in a critical chaos state according to the requirement of detection sensitivity; inputting a signal to be detected as perturbation of periodic excitation into the chaotic detection system model; carrying out numerical solution on the chaos detection system model through a preset high-precision numerical integration algorithm; performing state judgment on the chaos detection system model according to the obtained phase trajectory diagram and a preset phase change judgment criterion to obtain a detection conclusion; the effect is that the accuracy and precision of transmission gear early fault weak vibration signal detection are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of signal detection, and particularly relates to a chaotic detection method, device and medium for early fault signals of a transmission gear. BACKGROUND

[0002] Gears are widely used industrial products in transmission systems, and wear, peeling, pitting, cracks and the like of gears are common faults of gears. At present, most gear fault diagnosis technologies take vibration signals as research objects. Early fault vibration signals of transmission gears are often very weak and are easily submerged by conventional vibrations and noises, so it is difficult to effectively detect effective fault vibration signals from the conventional vibrations and noises.

[0003] Traditional weak vibration signal detection technologies are based on statistical characteristics of noises, and detect weak vibration signals from strong noise backgrounds according to different characteristics of signals and noises, and the key lies in suppressing noises, enhancing and extracting useful signals. Such detection methods mainly include correlation detection, synchronous accumulation, sampling integration and the like. They have certain limitations, which are reflected in that the signal-to-noise ratio threshold values of the signals that can be detected are relatively high, so that the detection performance will be seriously reduced, and then the accuracy and precision of detection of early fault weak vibration signals of gears are affected. SUMMARY

[0004] In order to overcome the deficiencies in the prior art, the purpose of the present application is to provide a chaotic detection method, device and medium for early fault signals of a transmission gear, so as to improve the accuracy and precision of detection of early fault weak vibration signals of the transmission gear.

[0005] In a first aspect, an embodiment of the present application provides a chaotic detection method for early fault signals of a transmission gear, and the method comprises the following steps:

[0006] A chaotic detection system model is constructed, and the chaotic detection system model is constructed based on a Duffing equation;

[0007] The model parameters of the chaotic detection system model are adjusted, so that the amplitude of the periodic excitation is kept at 15-20 times of the noise amplitude of the to-be-detected signal, so as to reduce the influence of background noise on the detection performance of the chaotic detection system model;

[0008] The amplitude of the periodic excitation is adjusted, so that the motion state of the chaotic detection system model gradually changes from a chaotic state to a periodic state, so as to determine a threshold value of the amplitude of the built-in periodic excitation;

[0009] According to the requirement of detection sensitivity, the amplitude of the built-in periodic excitation is adjusted to be less than the threshold value and to be within a detection sensitivity range from the threshold value, so that the chaotic detection system model is in a critical chaotic state;

[0010] The signal to be detected is taken as a periodic excitation perturbation input into the chaotic detection system model;

[0011] The Duffing equation of the chaotic detection system model is solved by a preset high-precision numerical integration algorithm to draw a phase trajectory diagram;

[0012] The chaotic detection system model is judged according to the obtained phase trajectory diagram and a preset phase change judgment criterion to obtain a detection conclusion; wherein the state includes a chaotic state and a large-scale periodic motion state.

[0013] As a preferred technical solution of the present application, the method further comprises:

[0014] When the same-period weak fault vibration signal is detected, the amplitude of the built-in periodic excitation is adjusted in a decreasing manner until the phase trajectory returns from the large-scale periodic motion state to the critical chaotic state, and the amplitude measurement value of the same-period weak fault vibration signal is obtained based on the difference between the amplitudes before and after the adjustment.

[0015] As a preferred technical solution of the present application, the phase change judgment criterion specifically comprises:

[0016] When the phase trajectories are regularly bound on the periodic orbit, it is judged to be in a large-scale periodic motion state;

[0017] When the phase trajectories are randomly distributed within the periodic orbit, it is judged to be in a chaotic state.

[0018] As a preferred technical solution of the present application, the method for making the Duffing chaotic detection system model in a critical chaotic state specifically comprises:

[0019] If in a chaotic state, the value of the amplitude γ of the periodic excitation is gradually increased until the stable large-scale periodic motion state is entered, thereby determining the threshold value γ d ;

[0020] Based on the γ d , the amplitude γ of the periodic excitation is reset so that the difference between them is within a preset range; wherein the reset γ does not exceed the threshold value; at this time, the system is in the critical chaotic state.

[0021] As a preferred technical solution of the present application, the identification of the current steady-state motion state to obtain a detection conclusion specifically comprises:

[0022] If the chaotic detection system model is still in a chaotic state, it indicates that the signal to be detected is pure noise and non-same-frequency periodic interference signal; if it enters a large-scale periodic motion, it indicates that the same-period weak fault vibration signal is detected from the signal to be detected.

[0023] The second aspect: the embodiment of the present application provides a kind of transmission gear early fault signal chaos detection device, the device includes:

[0024] Construction module, for constructing chaos detection system model;Wherein, the chaos detection system model is based on Duffing equation and is constructed;

[0025] Pre-adjustment module, for:

[0026] According to predetermined criteria, the model parameters of the chaos detection system model and the amplitude of built-in periodic excitation are pre-adjusted to obtain the required signal-to-noise ratio detection threshold and accurate critical chaos threshold, and the system model state is adjusted to the critical chaos state;

[0027] Detection module, for:

[0028] The signal to be detected is incorporated into the chaos detection system model in the critical chaos state as a perturbation of periodic excitation;

[0029] The above Duffing equation is numerically solved by a predetermined high-precision numerical integration method, so as to draw a phase trajectory diagram;The current steady state is identified according to the obtained phase trajectory diagram, and the phase change of the model state is judged according to the preset phase change judgment criterion, and the detection conclusion is obtained.

[0030] As a preferred technical solution of the present application, the device further comprises a measurement module, and the measurement module is used for:

[0031] When the same-period weak fault vibration signal is detected, the amplitude of the built-in periodic excitation is adjusted in a decreasing manner until the phase trajectory returns to the critical chaos state from the large-scale periodic motion state, and the amplitude measurement value of the same-period weak fault vibration signal is obtained based on the difference between the amplitudes before and after.

[0032] As a preferred technical solution of the present application, the phase change judgment criterion specifically includes:

[0033] When the phase trajectory is regularly bound on the periodic orbit, it is judged to be in the large-scale periodic motion state;

[0034] When the phase trajectory is randomly distributed within the periodic orbit, it is judged to be in the chaos state.

[0035] As a preferred technical solution of the present application, the method for making the Duffing chaos detection system model in the critical chaos state specifically includes:

[0036] If it is in the chaos state, the value of the amplitude γ of the periodic excitation is gradually increased until it enters the stable large-scale periodic motion state, and thus the threshold value γ is determined d;

[0037] Further based on the gamma d The amplitude gamma of the periodic excitation is reset so that the difference between the two is within a preset range, and the reset gamma does not exceed a threshold value; at this time, the system is in the critical chaotic state.

[0038] In a third aspect, the embodiments of the present application provide a computer readable storage medium, the computer storage medium stores a computer program, the computer program includes program instructions, and the program instructions make the processor execute the method of the first aspect when executed by the processor.

[0039] The technical scheme has the following advantages: the chaotic detection method, device and medium for early fault signals of a transmission gear provided by the present application realize detection of weak fault vibration signals of the transmission gear by taking the chaotic detection system model constructed based on the Duffing equation as a nonlinear system, utilize the characteristics that the chaotic system is sensitive to small signals and immune to noise under certain conditions, make the system be in a critical chaotic state, then incorporate the to-be-detected signal as a perturbation of the built-in periodic excitation into the system model, and utilize different responses of the Duffing chaotic oscillator to noise and target signals to realize detection of the target signal; the whole scheme directly determines whether early failure occurs by sensing the weak vibration signal, suppresses conventional vibration signals and noise, does not weaken the weak fault vibration signal, effectively reduces the interference of conventional vibration and noise, can perform high-sensitivity measurement, and improves the accuracy and precision of detection of the weak vibration signal of the transmission gear in the early failure stage. BRIEF DESCRIPTION OF DRAWINGS

[0040] Figure 1 A method flowchart of the chaotic detection method for early fault signals of a transmission gear provided by the embodiments of the present application is provided.

[0041] Figure 2 A scheme diagram of simulation verification of the chaotic detection method for early fault signals of a transmission gear provided by the embodiments of the present application is provided.

[0042] Figure 3 A phase trajectory diagram without to-be-detected signal input provided by the embodiments of the present application is provided.

[0043] Figure 4 A phase trajectory diagram with white noise with an amplitude of 0.2 added provided by the embodiments of the present application is provided.

[0044] Figure 5 A phase trajectory diagram with a vibration signal with the same period and an amplitude of 0.0003 added provided by the embodiments of the present application is provided.

[0045] Figure 6A phase trajectory diagram provided by the embodiment of the present application is added with white noise with an amplitude of 0.02;

[0046] Figure 7 A phase trajectory diagram provided by the embodiment of the present application is added with white noise with an amplitude of 0.02 and a vibration signal with an amplitude of 0.0003;

[0047] Figure 8 A structural schematic diagram of a chaotic detection device for an early fault signal of a transmission gear provided by the embodiment of the present application;

[0048] Figure 9 A structural schematic diagram of another chaotic detection device for an early fault signal of a transmission gear provided by the embodiment of the present application. DETAILED DESCRIPTION

[0049] The specific embodiments of the present application will be described in detail below, and it should be noted that the embodiments described herein are only used for illustration and do not limit the present application. In the following description, a large number of specific details are set forth in order to provide a thorough understanding of the present application. However, it is obvious to those skilled in the art that the present application does not have to be implemented with these specific details.

[0050] It should be noted that the terms "first", "second", and the like in the specification and claims of the present application and the above-described drawings are used to distinguish similar objects, and do not necessarily describe a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units does not have to be limited to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0051] Throughout the specification, the reference to "one embodiment", "an embodiment", "one example" or "an example" means that the specific features, structures or characteristics described in connection with the embodiment or example are included in at least one embodiment of the present application. Therefore, the phrases "in one embodiment", "in an embodiment", "one example" or "an example" appearing throughout the specification do not necessarily refer to the same embodiment or example. In addition, specific features, structures or characteristics can be combined in one or more embodiments or examples in any appropriate combination and / or sub-combination.

[0052] It should be noted that the technical terms of the present embodiment have their usual meanings understood by those skilled in the art, unless otherwise stated.

[0053] Duffing chaotic oscillator: A classical nonlinear dynamical system that is widely studied for its rich dynamical behavior, including periodic motion, bifurcation, and chaos, and serves as an important model for studying chaos theory, nonlinear dynamics, and complex systems.

[0054] Referring Figure 1 The embodiment of the present application provides a chaotic detection method for early fault signals of a transmission gear, which comprises the following steps:

[0055] S101, a chaotic detection system model is constructed; the chaotic detection system model is constructed based on a Duffing equation.

[0056] Specifically, the detection system model is established according to the following Duffing equation:

[0057]

[0058] where k is the damping ratio, a is the linear restoring force coefficient, b is the nonlinear restoring force coefficient, and γ is the amplitude of the built-in periodic excitation. With regard to the above Duffing system, the following conclusions are drawn:

[0059] (1) The excitation amplitude γ has a great influence on chaotic motion. In a large range, the system is in a chaotic state. When γ is greater than a certain threshold γ d , the system will enter a large-scale periodic motion state from the chaotic state.

[0060] (2) With the increase of the damping ratio k, the excitation amplitude that produces chaotic motion at the same frequency increases, and the frequency range also increases.

[0061] Based on the above conclusions, in order to reduce the influence of background noise on the minimum detection signal-to-noise ratio threshold of the system as much as possible, the damping ratio is adjusted so that the excitation amplitude is maintained at about 15-20 times the noise amplitude of the signal to be detected. At this time, γcos(t) plays a key role in the change of the system state.

[0062] S102, the model parameters of the chaotic detection system model are adjusted so that the amplitude of the periodic excitation is maintained at about 15-20 times the noise amplitude of the signal to be detected, so as to reduce the influence of background noise on the detection performance of the chaotic detection system model.

[0063] S103, the amplitude of the periodic excitation is adjusted so that the motion state of the chaotic detection system model gradually changes from chaotic state to periodic state, so as to determine the threshold of the built-in periodic excitation amplitude;

[0064] S104, according to the requirement of detection sensitivity, the amplitude of the built-in periodic excitation is adjusted to be less than the threshold and differ from the threshold by not more than the detection sensitivity range, so that the chaotic detection system model is in a critical chaotic state.

[0065] The method for making the Duffing chaotic detection system model in the critical chaotic state specifically comprises:

[0066] If in the chaotic state, the value of the amplitude γ of the periodic excitation is gradually increased until entering the stable large-scale periodic motion state, thereby determining the threshold value γ d ;

[0067] The amplitude γ of the periodic excitation is re-set based on the γ d , so that the difference between them is within a preset range; wherein the re-set γ does not exceed the threshold value; at this time, the system is in the critical chaotic state; the preset range can be flexibly set based on the requirement of detection sensitivity, so as to set the amplitude γ of the periodic excitation in the vicinity of γ d that is less than but as close as possible to γ

[0068] S105, the Duffing chaotic detection system model is input with the to-be-detected signal as a perturbation of the periodic excitation.

[0069] Specifically, the to-be-detected signal is incorporated into the system as a perturbation of the periodic excitation. The to-be-detected signal s is in the form of s=hcos(t)+zs; wherein h is the amplitude of the useful signal, i.e. the gear weak fault vibration signal; and zs is a noise signal, including the gear transmission system working frequency vibration signal and the white noise signal.

[0070] S106, the Duffing equation of the chaotic detection system model is numerically solved by a preset high-precision numerical integration algorithm, so as to draw a phase trajectory diagram.

[0071] The high-precision numerical integration algorithm adopts the fourth-order Runge-Kutta method to numerically solve the Duffing equation, and the state is plotted point by point in the phase plane to obtain the system phase trajectory diagram; when the system is stable in a certain motion form, it can be known through identifying the phase trajectory diagram whether it is in the chaotic state or the large-scale periodic state.

[0072] S107, the chaotic detection system model is judged according to the obtained phase trajectory diagram and a preset phase change judgment criterion, so as to obtain a detection conclusion; wherein the state includes the chaotic state and the large-scale periodic motion state.

[0073] In this embodiment, the phase change judgment criterion specifically comprises:

[0074] When the phase trajectories are regularly bound on the periodic orbit, it is judged to be in the large-scale periodic motion state.

[0075] When the phase trajectories are randomly distributed within the periodic orbit, it is determined that the system is in a chaotic state.

[0076] Due to the sensitivity of the chaotic system to weak vibration signals and the immunity to noise, if the chaotic detection system model is still in a chaotic state, it is indicated that the to-be-detected signal is a pure noise and a non-same-frequency periodic interference signal; if the system enters a large-scale periodic motion, it is indicated that a same-period weak fault vibration signal is detected from the to-be-detected signal.

[0077] The above method uses the Duffing chaotic detection system model based on the Duffing equation as a nonlinear system to detect the weak fault vibration signal of the transmission gear, uses the characteristics that the chaotic system is sensitive to small signals and immune to noise under certain conditions, puts the to-be-detected signal into the system model as a perturbation of the built-in periodic excitation, and uses the different responses of the Duffing chaotic oscillator to noise and target signals to realize the detection of the target signal; the whole scheme directly determines whether an early fault occurs through the induction of the weak vibration signal, suppresses the conventional vibration signal and noise, and does not weaken the weak fault vibration signal, which can effectively reduce the interference of the conventional vibration and noise, can perform high-sensitivity measurement, and improves the accuracy and precision of the early fault weak vibration signal detection of the transmission gear.

[0078] Further, the method further comprises:

[0079] When the same-period weak fault vibration signal is detected, the amplitude of the built-in periodic excitation is adjusted in a decreasing manner until the phase trajectory returns to the critical chaotic state from the large-scale periodic motion state, and the amplitude measurement value of the same-period weak fault vibration signal is obtained based on the difference between the amplitudes before and after the adjustment.

[0080] Specifically, when the same-period weak fault vibration signal is detected, the amplitude γ of the built-in periodic excitation of the system is adjusted in a decreasing manner until the phase trajectory of the system returns to the critical chaotic state from the large-scale periodic motion state, and the amplitude measurement value h0 of the same-period weak fault vibration signal is obtained. d

[0081] h0 = γ d - γ0

[0082] Further, in implementation, the influence of background noise on the detection performance of the system is analyzed

[0083] The influence of the background noise in the to-be-detected signal on the detection performance includes the following two aspects:

[0084] (1) The larger the noise, the higher the lowest detection threshold

[0085] ​When the added background noise is large, the threshold value of the useful signal converted to large-scale periodic state will be increased accordingly, so that the minimum amplitude of the periodic excitation of the phase transition of the system is also increased, and the minimum detection threshold of the signal-to-noise ratio of the signal that can be detected by the system is also increased. If the noise is too large, the detection performance of the system will be seriously degraded. However, the noise does not affect the accuracy of the frequency detection of the useful signal.

[0086] (2) The deeper the chaos, the less the noise affects the detection performance of the system

[0087] The resistance to the absolute strength of the noise is different when the depth of chaos is different. When the value of the critical excitation γ is far from the threshold value γ d , the system is still far from the true critical state, and the influence of noise is small; when the value of the critical excitation γ is close to the threshold value γ d , the system is close to the true critical state, and the influence of noise is large.

[0088] Further, the influence of phase difference and frequency difference on detection performance is analyzed

[0089] Since there may be a certain frequency difference (denoted as Δω) and phase difference (denoted as ) between the weak vibration signal in the actual signal to be measured and the periodic excitation, it is necessary to analyze the influence of frequency difference and phase difference on the detection performance.

[0090] (1) Only phase difference exists

[0091] When the system has no noise input, and the phase difference is about , the system can have a phase transition (from chaotic state to periodic state), that is, the system can detect the weak fault vibration signal. However, the existence of phase difference will cause measurement error of the measurement amplitude of the weak vibration signal, and the larger the phase difference , the larger the measurement error. The absolute error value h-h0 of the measurement can be estimated as follows:

[0092]

[0093] When the noise exists in the signal to be measured, the noise also has an influence on the measurement error of the system, which increases the measurement error of the weak vibration signal. Therefore, when considering the influence of phase difference on the measurement error, the influence of noise on the measurement error also needs to be considered.

[0094] ​The input noise affects the allowable phase difference between the weak vibration signal and the excitation signal. In the case of the same weak vibration signal input, the stronger the input noise, the more stringent the requirement for the phase difference between the weak vibration signal and the excitation signal for detecting the existence of the weak vibration signal, and the smaller the phase difference range in which the weak vibration signal can be detected; in the case of the same noise input, the smaller the weak vibration signal amplitude, the smaller the allowable phase difference range between the weak vibration signal and the excitation signal.

[0095] (2) Only frequency difference exists

[0096] Defining the total excitation of the system as the superposition of the periodic excitation and the weak fault vibration signal in the signal to be detected, it can be deduced that the amplitude varies between γ d -h and γ d +h. Therefore, the system state will regularly transform between the chaotic state and the large-scale periodic state, and the time period of the transformation is 2π / Δω, that is, the system will have regular intermittent chaotic phenomenon of being chaotic at times and periodic at times.

[0097] When Δω is very small, the system maintains the stable periodic state and the stable chaotic state for a long time, the system can well respond to the slow change of the excitation, and the intermittent chaotic phenomenon is very obvious, that is, the phase transition of the Duffing chaotic oscillator is sensitive to small signals with a small frequency difference.

[0098] When Δω is large, the phase transition of the system occurs too fast, and the system is difficult to maintain a stable chaotic or periodic state for a long time, and the sensitivity of the system to small signals with a large frequency difference is also reduced, so the intermittent chaotic phenomenon is difficult to observe, which indicates that the phase transition of the Duffing chaotic oscillator also has strong immunity to periodic interference with a large frequency difference.

[0099] (3) Phase difference and frequency difference exist at the same time

[0100] If Δω is very small, the system will repeat the intermittent chaotic phenomenon with a period of 2π / Δω, that is, the signal to be detected contains an approximately same frequency (0.97-1.03 times) signal, and even if the amplitude is very small, it will also cause the motion trajectory of the system to rapidly transit to a large-scale periodic state and the periodic motion is very stable. If Δω decreases, the period increases. When Δω decreases to zero, that is, there is no frequency difference, the system motion can be regarded as an intermittent chaotic motion with an infinite period, and whether the phase transition occurs or not depends on the phase difference . If the phase transition occurs, the system will make stable periodic motion in an infinite period; if the phase transition does not occur, the system will always remain in a chaotic state in an infinite period.

[0101] It can be verified that the Duffing chaotic system has a band-pass characteristic for detecting a weak sinusoidal signal when the excitation amplitude, the noise amplitude and the phase difference meet certain conditions.

[0102] Referring to Figure 2 The simulation verification scheme of the method for detecting early fault signals of a transmission gear provided by the embodiment of the application is shown in FIG. 1. The simulation verification scheme comprises the following contents.

[0103] Supposing that the periodic frequency of a weak fault vibration signal in a signal to be detected is ω (rad / s), the signal to be detected is incorporated into a Duffing system as a perturbation of a periodic excitation, t = ω · t is set in equation (1), and equation (1) is rewritten into a state equation form, and equation (1) becomes:

[0104]

[0105] A simulation model is built according to the above equation, as shown in FIG. 2. In the equation, a = 1, b = 1, k = 0.5, and the value of ω is adjusted according to the frequency of an actual signal to be detected. Gain3 and Gain correspond to h and γ in the equation respectively, and Gain2 is the amplitude of white noise. Figure 2

[0106] (1) Measurement of a critical chaotic state

[0107] In the simulation, ω = 750 × 2π. First, the external input signal and the noise are both set to 0, and no signal to be detected is input. By adjusting the value of Gain, the result obtained by simulation is observed and judged. When Gain is adjusted near the threshold value γ d , it can be observed that the phase trajectory of the chaotic system changes from a chaotic state to a stable periodic state, so that the value of the threshold value γ d is obtained. γ is set to the threshold value γ d , and the phase trajectory is in a chaotic critical state, and then various external signals are added for performance detection.

[0108] (2) Addition of a pure noise signal

[0109] Only zs is incorporated into the system as white noise, and it is found that the phase trajectory of the system is in a chaotic state. By continuously increasing the power (amplitude) of zs, the system remains in a chaotic state unchanged. It can be seen that although the noise is strong, the attractor can still confine the phase point in the track, which indicates that the chaotic system in the embodiment of the application has strong immunity to noise. The influence of the white noise amplitude of 0.2 on the phase trajectory of the system is shown in FIG. 3. Figure 4

[0110] (3) Addition of a pure periodic signal

[0111] ​​Only the same period weak vibration signal is incorporated into the system, the system phase trajectory is immediately changed from chaotic state to stable periodic state. It shows that the chaotic system in the embodiment of the application has sensitivity to very small same period external signal. The influence of adding the same period vibration signal with amplitude of 0.0003 to the system phase trajectory is shown in Figure 5 .

[0112] (4) adding the to-be-detected periodic signal mixed with noise

[0113] The same period weak vibration signal mixed with white noise is incorporated into the system, and the amplitude of the built-in periodic excitation is kept at 15-20 times of the noise amplitude. At this time, the chaotic system has immunity to noise, but is very sensitive to the periodic signal. The phase trajectory quickly enters stable periodic motion from chaos, which shows that the system detects the same period weak vibration signal from the to-be-detected signal. The influence of adding the white noise with amplitude of 0.02 is shown in Figure 6 , and the influence of adding the white noise with amplitude of 0.02 and the same period vibration signal with amplitude of 0.0003 is shown in Figure 7 .

[0114] Adjusting the amplitude γ of the built-in periodic excitation, when the phase trajectory appears a critical state again, the difference between γ d and γ is the amplitude of the same period weak vibration signal in the to-be-detected signal.

[0115] Based on the same inventive concept as the above chaotic detection method of the early fault signal of a transmission gear, the embodiment of the application further provides a chaotic detection device of an early fault signal of a transmission gear, which is shown in Figure 8 , and the device comprises:

[0116] A construction module is configured to construct a chaotic detection system model, wherein the chaotic detection system model is constructed based on a Duffing equation.

[0117] A pre-adjustment module is configured to:

[0118] According to a predetermined criterion, the model parameters of the chaotic detection system model and the amplitude of the built-in periodic excitation are pre-adjusted to obtain a required signal-to-noise ratio detection threshold and an accurate critical chaotic threshold, and the state of the system model is adjusted to a critical chaotic state.

[0119] A detection module is configured to:

[0120] The to-be-detected signal is incorporated into the chaotic detection system model in a critical chaotic state as a perturbation of the periodic excitation.

[0121] The Duffing equation is solved by a preset high-precision numerical integration method to draw a phase trajectory diagram; the current steady state is identified according to the obtained phase trajectory diagram, and the phase change of the model state is judged according to a preset phase change judgment criterion to obtain a detection conclusion.

[0122] The predetermined criterion includes: the amplitude of the periodic excitation is kept at 15-20 times of the noise amplitude of the signal to be measured, so as to reduce the influence of background noise on the detection performance of the chaotic detection system model;

[0123] The amplitude of the periodic excitation is adjusted to gradually change the motion state of the chaotic detection system model from chaotic state to periodic state, so as to determine the threshold of the built-in periodic excitation amplitude.

[0124] The phase change judgment criterion specifically includes:

[0125] When the phase trajectories are regularly bound on the periodic orbit, it is judged to be in a large-scale periodic motion state;

[0126] When the phase trajectories are randomly distributed within the periodic orbit, it is judged to be in a chaotic state.

[0127] The method for making the Duffing chaotic detection system model in a critical chaotic state specifically includes:

[0128] If in a chaotic state, the value of the amplitude γ of the periodic excitation is gradually increased until a stable large-scale periodic motion state is entered, thereby determining the threshold γ d ;

[0129] The amplitude γ of the periodic excitation is reset based on the γ d , so that the difference between them is within a preset range; wherein the reset γ does not exceed the threshold; at this time, the system is in the critical chaotic state.

[0130] The device detects the weak fault vibration signal of the transmission gear by constructing a Duffing chaotic detection system model as a nonlinear system, uses the characteristics that the chaotic system is sensitive to small signals and immune to noise under certain conditions, makes it in a critical chaotic state, then incorporates the signal to be measured as a perturbation of the built-in periodic excitation into the system model, and uses the different responses of the Duffing chaotic oscillator to noise and target signals to realize the detection of the target signal.

[0131] Further, in another embodiment, the device further includes a measurement module based on the above scheme, the measurement module is used for:

[0132] When the same-period weak fault vibration signal is detected, the amplitude of the built-in periodic excitation is adjusted in a decreasing manner until the phase trajectory returns from the large-scale periodic motion state to the critical chaotic state, and the amplitude measurement value of the same-period weak fault vibration signal is obtained based on the difference between the amplitudes before and after the adjustment.

[0133] The embodiment of the present application further provides a computer readable storage medium, the computer storage medium stores a computer program, the computer program comprises program instructions, and the program instructions make the processor execute the method in the first aspect when executed by the processor.

[0134] The computer readable storage medium can be the memory of the computer terminal, for example, the hard disk or the memory of the terminal. The computer readable storage medium can also be the external storage device of the terminal, for example, the plug-in hard disk, the smart media card (SMC), the secure digital (SD) card, the flash card and the like equipped on the terminal. Further, the computer readable storage medium can also include the memory of the terminal and the external storage device. The computer readable storage medium is used for storing the computer program and other programs and data required by the terminal.

[0135] The computer readable storage medium of the embodiment executes the method in the first embodiment, and details are not described herein.

[0136] Those skilled in the art can realize that the system modules and method steps described in combination with the embodiments disclosed herein can be realized by electronic hardware, computer software or a combination of both. In order to clearly illustrate the interchangeability of hardware and software, the components and steps of each example have been described in the above description in general terms. Whether the functions are realized in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to realize the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0137] Finally, it should be noted that the above description is merely a specific implementation of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A chaos detection method for early fault signals of transmission gears, characterized in that: The method comprises: Constructing a chaos detection system model; the chaos detection system model is constructed based on the Duffing equation; Adjusting the model parameters of the chaos detection system model so that the amplitude of its periodic excitation is maintained at 15-20 times the noise amplitude of the signal to be measured, so as to reduce the impact of background noise on the detection performance of the chaos detection system model; Adjusting the amplitude of the periodic excitation so that the motion state of the chaos detection system model gradually changes from a chaotic state to a periodic state, thereby determining a threshold value of the built-in periodic excitation amplitude; According to the detection sensitivity requirement, the amplitude of the built-in periodic excitation is adjusted to be less than the threshold and the difference from the threshold does not exceed the detection sensitivity range, so that the chaos detection system model is in a critical chaotic state; Inputting the signal to be detected into the chaos detection system model as a perturbation of periodic excitation; The Duffing equation of the above chaos detection system model is numerically solved by a preset high-precision numerical integration algorithm to draw a phase trajectory diagram; The state of the chaos detection system model is judged according to the obtained phase trajectory diagram and the preset phase change judgment criterion to obtain a detection conclusion; wherein the state includes a chaotic state and a large-scale periodic motion state.

2. The method for detecting early stage fault signals of transmission gears according to claim 1, characterized in that: The method further comprises: When a weak fault vibration signal with the same period is detected, the amplitude of the built-in periodic excitation is gradually adjusted until the phase trajectory returns to the critical chaotic state from the large-scale periodic motion state, and the amplitude measurement value of the weak fault vibration signal with the same period is obtained based on the difference between the previous and next amplitudes.

3. The method for detecting early stage fault signals of transmission gears according to claim 1, characterized in that: The phase change judgment criteria specifically include: When the phase trajectories are all regularly bound to periodic orbits, it is judged to be in a state of large-scale periodic motion; When the phase trajectory is randomly distributed within the periodic orbit, it is judged to be in a chaotic state.

4. The method for detecting early stage fault signals of transmission gears according to claim 3, characterized in that: The method of making the Duffing chaos detection system model in a critical chaotic state specifically includes: If it is in a chaotic state, gradually increase the amplitude γ of the periodic excitation until it enters a stable large-scale periodic motion state, thereby determining the threshold γ d ; Based on the γ d The amplitude γ of the periodic excitation is reset so that the difference between the two is within a preset range; wherein the reset γ does not exceed the threshold; at this time, the system is in the critical chaotic state.

5. The method for detecting early stage fault signals of transmission gears according to claim 1, characterized in that: Identify the current steady-state motion state and draw the following conclusions: If the chaos detection system model is still in a chaotic state, it means that the signal to be measured is pure noise and a non-same-frequency periodic interference signal; if it enters a large-scale periodic motion, it means that a weak fault vibration signal of the same period is detected from the signal to be measured.

6. A chaos detection device for early fault signals of transmission gears, characterized in that: The device comprises: A construction module, used to construct a chaos detection system model; wherein the chaos detection system model is constructed based on the Duffing equation; Presetting modules for: According to predetermined criteria, the model parameters and the built-in periodic excitation amplitude of the chaos detection system model are pre-adjusted to obtain the required signal-to-noise ratio detection threshold and the accurate critical chaos threshold, and the system model state is adjusted to the critical chaos state; Detection module for: Incorporating the signal to be detected as a perturbation of periodic excitation into the chaos detection system model in the critical chaotic state; The above-mentioned Duffing equation is numerically solved by a preset high-precision numerical integration method to draw a phase trajectory diagram; the current steady-state motion state is identified based on the obtained phase trajectory diagram, and the phase change of the model state is judged according to the preset phase change judgment criterion to draw a detection conclusion.

7. The chaos detection device for early fault signals of transmission gears according to claim 6, characterized in that: The device further comprises a measuring module, wherein the measuring module is configured to: When a weak fault vibration signal with the same period is detected, the amplitude of the built-in periodic excitation is gradually adjusted until the phase trajectory returns to the critical chaotic state from the large-scale periodic motion state, and the amplitude measurement value of the weak fault vibration signal with the same period is obtained based on the difference between the previous and next amplitudes.

8. The chaos detection device for early fault signals of transmission gears according to claim 6, characterized in that: The phase change judgment criteria specifically include: When the phase trajectories are all regularly bound to periodic orbits, it is judged to be in a state of large-scale periodic motion; When the phase trajectory is randomly distributed within the periodic orbit, it is judged to be in a chaotic state.

9. The chaos detection device for early fault signals of transmission gears according to claim 7, characterized in that: The method of making the Duffing chaos detection system model in a critical chaotic state specifically includes: If it is in a chaotic state, gradually increase the amplitude γ of the periodic excitation until it enters a stable large-scale periodic motion state, thereby determining the threshold γ d ; Based on the γ d The amplitude γ of the periodic excitation is reset so that the difference between the two is within a preset range; wherein the reset γ does not exceed the threshold; at this time, the system is in the critical chaotic state.

10. A computer-readable storage medium storing a computer program, wherein the computer program comprises program instructions, and when the program instructions are executed by a processor, the processor is caused to execute the method according to any one of claims 1 to 5.

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