Method for representing balanced operation state of transmission system of tower pumping unit

Abstract

The invention discloses a method for characterizing the balanced operation state of a transmission system of a tower pumping unit, and relates to the technical field of state monitoring and fault diagnosis. The method comprises the following steps of: quantifying the symmetry of upper and lower strokes by extracting vibration signal characteristics of a transmission system of the tower pumping unit in a constant-speed operation section, so as to accurately evaluate the balance state of the system; in the acceleration stage, focusing a start-stop transient process, and diagnosing a non-stationary behavior caused by inertial impact; based on waterfall spectrum analysis, the gear meshing state is monitored in real time, and early abrasion and faults are recognized; through multi-dimensional vibration characteristic analysis, the axis deviation problem of the multi-stage series shafting is accurately diagnosed; and finally, the comprehensive state evaluation module realizes quantitative judgment of the overall operation state of the tower crane through multi-dimensional fusion of the state indexes of the subsystems. Accurate diagnosis of the balance degree, the acceleration stability, the speed reducer gear meshing state and the shafting centering condition of a transmission system of the tower pumping unit is achieved, and the technical suitability is improved.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of state monitoring and fault diagnosis, in particular to a tower pumping unit transmission system balanced operation state representation method. BACKGROUND

[0002] As a new generation of lifting equipment, the tower pumping unit has become an important equipment for oil fields to realize cost reduction and efficiency increase, with the advantages of simple transmission, compact structure and long stroke and short stroke. In order to ensure the long-term reliable operation of the new equipment, it is of great significance to implement effective state monitoring. However, the widely used online monitoring technology is mostly based on the structural characteristics and fault modes of conventional rotating machinery or traditional beam pumping units, and has not formed a special monitoring scheme applicable to tower pumping units. The existing methods generally have problems of insufficient professional adaptability and incomplete working condition coverage when applied to tower machines, and it is difficult to effectively capture the unique fault characteristics of the transmission system of the tower machine in variable working conditions and forward and reverse rotation. Therefore, in order to make up for this technical gap, it is necessary to carry out special state monitoring technology research on tower pumping units, and to build a diagnosis system deeply adapted to the structural characteristics and operation mechanism of the tower pumping unit, so as to realize accurate perception of the running state of the equipment and provide core technical support for its safe, efficient and long-period operation.

[0003] In the prior art, most state monitoring and evaluation methods are still designed for conventional rotating machinery or beam pumping units. However, these methods fail to fully consider the operation characteristics of tower pumping units in the working process in terms of vibration feature extraction, stroke identification and health evaluation logic, making it difficult to analyze the signals of tower pumping units under variable working conditions, and the integrated transmission structure is difficult to accurately model, resulting in obvious technical adaptability deficiency in the application of tower pumping units. SUMMARY

[0004] Therefore, it is necessary to provide a tower pumping unit transmission system balanced operation state representation method in view of the above technical problems.

[0005] The application adopts the following technical scheme: The application provides a tower pumping unit transmission system balanced operation state representation method, which comprises the following steps: Obtaining the original vibration signal of each stroke cycle of the tower pumping unit transmission system during operation; and extracting the uniform speed vibration signal, the acceleration vibration signal and the vibration signal of the bearing seat at both ends of the deceleration roller of the tower pumping unit transmission system from the original vibration signal of each stroke cycle; Calculating the instantaneous effective value of the uniform speed vibration signal of each stroke cycle; determining the balance degree index of the uniform speed running stage of the tower pumping unit transmission system in each stroke cycle according to the instantaneous effective value of the uniform speed vibration signal; instantaneous effective value of the acceleration vibration signal of each stroke cycle is calculated, and an instantaneous effective value time sequence curve reflecting the instantaneous change rule of vibration energy is drawn; an impact peak value, an impact density and a curve gradient are extracted from the instantaneous effective value time sequence curve respectively; a stability index of the acceleration running stage of the tower pumping unit transmission system in each stroke cycle is determined according to the impact peak value, the impact density and the curve gradient change rate; The vibration signals of the bearing seats at both ends of the reduction drum are subjected to short-time Fourier transform with a sliding window, local frequency spectra are obtained and stacked by time, and a three-dimensional time-frequency waterfall spectrum reflecting the dynamic evolution of vibration energy of the secondary planetary reducer in the reduction drum in the whole process of acceleration, constant speed and deceleration is drawn; a characteristic frequency trajectory, an edge frequency band energy proportion and a harmonic energy index are extracted from the three-dimensional time-frequency waterfall spectrum respectively, and a planetary reducer health index is determined; The frequency multiplication amplitude feature, the shafting phase relationship feature and the edge frequency band modulation feature of the vibration signals of the bearing seats at both ends of the reduction drum are extracted; and an alignment degree index of the reduction drum fusing axial and radial vibration information is determined according to the frequency multiplication amplitude feature, the shafting phase relationship feature and the edge frequency band modulation feature. According to the balance degree index, the stability index, the planetary reducer health index and the alignment degree index, a comprehensive health index is determined to represent the running state of the tower pumping unit transmission system.

[0006] Preferably, according to the instantaneous effective value of the constant speed vibration signal, a balance degree index of the tower pumping unit transmission system in the constant speed running stage of each stroke cycle is calculated, specifically including: According to the instantaneous effective value of the constant speed vibration signal, a balance amplitude index and a balance direction index of the tower pumping unit transmission system in the constant speed running stage of each stroke cycle are calculated, and the formula is: ; ; In the formula, and are the balance amplitude index and the balance direction index of the tower pumping unit transmission system in the constant speed running stage of each stroke cycle, is the instantaneous effective value of the tower pumping unit transmission system in the constant speed running stage of the upstroke process; is the instantaneous effective value of the tower pumping unit transmission system in the constant speed running stage of the downstroke process; According to the balance amplitude index and the balance direction index, a balance degree index of the tower pumping unit transmission system in the constant speed running stage of each stroke cycle is calculated, and the formula is: SBI = BSI x sign(BDI) ; In the formula, SBI is the balance degree index of the tower pumping unit transmission system in the constant speed running stage of each stroke cycle.

[0007] Preferably, according to the impact peak value, impact density and curve gradient change rate, the smoothness index of the tower pumping unit transmission system in the acceleration running stage of each stroke cycle is calculated, specifically comprising: The ratio of the impact peak value to the baseline instantaneous effective value, the ratio of the impact frequency per unit time to the reference impact density, and the ratio of the curve gradient change rate to the reference gradient variance are calculated respectively to obtain the normalized impact amplitude, the normalized impact density and the normalized gradient variance of the tower pumping unit transmission system in the acceleration running stage of each stroke cycle; According to the normalized impact amplitude, the normalized impact density and the normalized gradient variance, the smoothness index of the tower pumping unit transmission system in the acceleration running stage of each stroke cycle is calculated, and the formula is: ; In the formula, is the smoothness index of the tower pumping unit transmission system in the acceleration running stage of each stroke cycle, is the normalized impact amplitude, reflecting the strength of transient impact; is the normalized impact density, reflecting the frequency of acceleration section impact; is the normalized gradient variance, reflecting the curve smoothness or steep change of the instantaneous effective value time sequence curve; 、 and are the impact strength weight, impact frequency weight and curve smoothness weight respectively.

[0008] Preferably, before performing sliding window short-time Fourier transform on the vibration signal of the bearing seat at both ends of the deceleration drum, it further comprises: The planetary carrier rotation frequency and the sun gear rotation frequency of the two-stage planetary reducer are calculated respectively, and the formula is: ; ; ; In the formula, is the planetary carrier rotation frequency, is the planetary carrier input rotation speed, is the deceleration ratio of the reducer, is the sun gear rotation speed, is the sun gear rotation frequency; According to the planetary carrier rotation frequency and the sun gear rotation frequency, the sun gear-planet gear meshing frequency and the planet gear-ring gear meshing frequency are calculated, and the formula is: ; ; In the formula, and These are the meshing frequencies of the sun gear-planet gear and the planet gear-ring gear, respectively. The number of teeth on the sun gear. The rotational frequency of the gear ring. This represents the number of teeth on the planetary gear.

[0009] Preferably, the extraction of the feature frequency trajectory specifically includes: The peak tracking algorithm is used to locate the energy extreme points of the planet carrier rotation frequency, the sun gear-planet gear meshing frequency, and the planet gear-ring gear meshing frequency in the three-dimensional time-frequency waterfall spectrum; Interpolating the energy extrema points on the time axis of the three-dimensional time-frequency waterfall spectrum yields a continuous characteristic frequency trajectory.

[0010] Preferably, the extraction of the sideband energy percentage specifically includes: Identify the sideband energy on both sides of the sun gear-planet gear meshing frequency and the planet gear-ring gear meshing frequency in the three-dimensional time-frequency waterfall spectrum; The ratio of the sideband energy to the main frequency energy is calculated to obtain the sideband energy percentage.

[0011] Preferably, the extraction of the harmonic energy index specifically includes: The vibration signal of the bearing housing at both ends of the deceleration drum in the three-dimensional time-frequency waterfall spectrum is converted to the frequency domain by Fourier transform, the fundamental wave and each single harmonic are separated, and the frequency and amplitude of the vibration signal are extracted. Based on the relationship that energy is proportional to the square of amplitude, calculate the energy of each harmonic, the total harmonic energy, and the fundamental energy. The harmonic energy index, which is used to evaluate the energy distribution characteristics, is obtained by weighted summation of the ratio of each single harmonic energy to the total harmonic energy.

[0012] Preferably, based on the harmonic amplitude characteristics, shaft phase relationship characteristics, and sideband modulation characteristics, the alignment index of the reduced roller's fused axial and radial vibration information is calculated, specifically including: The formula for calculating the normalized harmonic power ratio is: ; In the formula, This is the amplitude ratio of the harmonic energy to the frequency conversion energy, i.e., the harmonic amplitude characteristic. This is an adjustment coefficient used to control the saturation rate of this index; The formula for calculating the normalized phase difference is: ; In the formula, To normalize the phase difference, It is the absolute value of the phase difference between the motor end and the drum end in the axial vibration signal, i.e., the characteristic of the shaft system phase relationship; The formula for calculating the normalized sideband modulation depth is: ; In the formula, To normalize the sideband modulation depth, This is the ratio of the total energy of the sidebands to the energy of the main frequency. This is the adjustment coefficient; Based on the normalized harmonic power ratio, normalized phase difference, and normalized sideband modulation depth, the neutrality index is calculated using the following formula: ; In the formula, These are the weight coefficients, representing the contribution of each feature to the overall midpoint state, which must satisfy... .

[0013] Preferably, the formula for calculating the comprehensive health index is as follows: ; In the formula, For the comprehensive health index, As a balance index, As a stability index, For the health index of the planetary decelerator, For the moderate index, the weighting coefficient 、 、 、 These are the balance index, stability index, planetary reducer health index, and their contribution weights to the moderate index, respectively. .

[0014] Preferably, the method further includes: Based on the aforementioned comprehensive health index, balance index, stability index, planetary reducer health index, and centering index, a multi-scale early warning mechanism for the tower pumping unit transmission system is established, including: If any operating index of the tower pumping unit's drive system suddenly drops by 20% within a single operating cycle, a yellow warning will be issued, prompting operators to check for sudden malfunctions. When any operating index of the tower pumping unit's transmission system shows a continuous downward trend for three consecutive monitoring cycles, an orange alert is issued, indicating that the components of the tower pumping unit's transmission system have entered a period of accelerated wear. When the comprehensive health index of the tower pumping unit transmission system continues to be lower than the preset maintenance threshold, a red warning is triggered, indicating that the equipment has entered an unhealthy state and needs to be shut down for maintenance immediately.

[0015] The above-mentioned at least one technical solution adopted in this invention can achieve the following beneficial effects: In the method for characterizing the balanced operation state of a tower pumping unit transmission system provided by this invention, the uniform speed stage of the tower pumping unit is taken as the benchmark operating condition. Vibration signals of this stage are extracted, a comprehensive balance index is constructed, and combined with load information and historical trends, the actual balance state of the tower pumping unit is accurately quantified and predictively diagnosed. For the operating characteristics of the acceleration stage, vibration signals of the acceleration segment are extracted and their multi-dimensional characteristics are quantified, and a comprehensive stability index is constructed, achieving quantitative characterization of nonlinear vibration impact and accurate diagnosis of stability in the acceleration segment. Considering the closed transmission structure characteristics of the integrated planetary reducer and drum of the tower pumping unit, a theoretical characteristic frequency template for the two-stage planetary reducer is constructed, and the early characteristic frequency of the two-stage planetary reducer inside the drum is extracted. By identifying specific meshing frequencies caused by periodic faults, separating the main frequency and harmonic interference, and establishing a fused health index, sensitive detection of micro-gear faults was achieved. For the abnormal vibration problem caused by misalignment in the multi-stage series shaft system of a tower-type pumping unit, a fused alignment index integrating axial and radial vibration information was constructed by extracting the amplitude, harmonics, phase, and modulation characteristics of the vibration signal. This enabled accurate identification and quantitative assessment of misalignment faults. Finally, combining the characteristics of the tower machine's planetary roller drive, variable load stroke, and multi-stage transmission, a weighted adaptive fusion mechanism was designed. By fusing the state indices of each subsystem from multiple dimensions, a dedicated comprehensive evaluation index for the tower machine's operating status was constructed, enabling quantitative judgment of the overall operating status of the tower machine.

[0016] In addition, this invention establishes a multi-scale trend early warning system based on the above indicators, develops a predictive maintenance and decision support process, and realizes quantitative assessment and predictive early warning of the overall operating status. Attached Figure Description

[0017] 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:

[0018] Figure 1 A flowchart illustrating a method for characterizing the balanced operating state of a tower pumping unit transmission system provided by the present invention; Figure 2 A structural diagram of the tower pumping unit transmission system, which is provided by the present invention as a method for characterizing the balanced operation state of a tower pumping unit transmission system; Figure 3 The overall architecture diagram of the method for characterizing the balanced operation state of a tower pumping unit transmission system provided by the present invention; Figure 4The instantaneous RMS diagram of the measuring point on the bearing support at the right end of the deceleration drum in the uniform speed stage of the uniform speed stage is provided by the present invention for a method of characterizing the balanced operation state of the transmission system of a tower pumping unit. Figure 5 The instantaneous RMS diagram of the measuring point on the bearing support at the right end of the deceleration drum during the acceleration phase of the acceleration phase of the method for characterizing the balanced operation state of the transmission system of a tower pumping unit provided by the present invention. Figure 6 The impulse vibration spectrum diagram of the method for characterizing the balanced operation state of the transmission system of a tower pumping unit provided by the present invention; Figure 7 The spectrum diagram of the measuring point on the bearing support at the right end of the reduction drum in the method for characterizing the balanced operation state of the transmission system of a tower pumping unit provided by the present invention. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this application will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments in the specification without creative effort are within the scope of protection of this application.

[0020] The application of traditional solutions to tower-type pumping units suffers from significant technical compatibility issues, specifically in the following three aspects: Differences in operating conditions lead to insufficient adaptability of traditional analysis models: Existing methods typically analyze acceleration, constant speed, and deceleration stages uniformly at the signal processing level, ignoring differences in operating conditions such as alternating forward and reverse rotation of tower pumping unit motors, stroke asymmetry, and speed change processes.

[0021] The integration of transmission systems limits the identification capabilities of traditional diagnostic methods: existing diagnostic models for rotating machinery mostly focus on single-stage gears or open transmissions. Tower-type pumping units use a two-stage planetary reduction drum integrated transmission structure. Existing technologies lack the ability to perform detailed analysis on the unique structure of tower machines. At the same time, the identification of misalignment faults in the transmission system still uses general models.

[0022] Static assessment systems are ill-suited to the operating characteristics of tower cranes: existing condition assessment systems are mostly based on fixed thresholds and constant weights to construct health index models, without considering the non-stationary and time-varying characteristics of tower cranes under load cycles, stroke ratios and speed changes.

[0023] To address the key issues in existing technologies for monitoring the condition of tower pumping unit transmission systems—namely, difficulties in signal analysis under varying operating conditions, challenges in accurately modeling integrated transmission structures, and the lack of time-varying adaptive mechanisms for health assessment—this invention proposes a collaborative characterization and diagnostic method based on multi-source vibration signal analysis to achieve accurate identification of the condition of the tower pumping unit transmission system.

[0024] The technical solutions provided by the various embodiments of this application are described in detail below with reference to the accompanying drawings.

[0025] Figure 1 This is a schematic flowchart of a method for characterizing the balanced operating state of a tower pumping unit transmission system according to the present invention, which specifically includes the following steps: S101: Acquire the original vibration signal of each stroke cycle of the tower pumping unit drive system during operation; and extract the uniform vibration signal, acceleration vibration signal and vibration signal of the bearing seats at both ends of the reduction drum of the tower pumping unit drive system from the original vibration signal for each stroke cycle.

[0026] Specifically, see Figure 2 The transmission system of a tower-type pumping unit mainly consists of a drive motor, a reduction drum, a counterweight block, and a sucker rod string. The power transmission path is as follows: the drive motor is connected to the reduction drum via a coupling; the reduction drum, through the winding and unwinding of a belt, pulls the counterweight block and the sucker rod string in a reciprocating linear motion, thereby driving the downhole pump to complete the crude oil extraction operation.

[0027] The transmission system of the tower-type pumping unit adopts a planetary reduction drum integrated transmission and a multi-stage series shaft system, driven by a motor in both forward and reverse rotation. During the up and down strokes, the system vibration exhibits three stages: acceleration, constant speed, and deceleration, and the instantaneous vibration characteristics change significantly with operating conditions. Smooth operation and the structural safety of the transmission system are key factors in maintaining the continuous and stable production of the tower-type pumping unit. The former is determined by the mechanical compensation of the counterweight and the inertial impact under varying operating conditions: the counterweight directly affects the balance of the constant speed segment; imbalance will lead to increased vibration, increased energy consumption, and exacerbated mechanical fatigue. The impact load generated by the reverse rotation of the motor during start-up, shutdown, and reversal dominates the stability of the acceleration / deceleration segment; improper control will weaken the dynamic response of the transmission chain and shorten gear life, thereby further affecting the overall stability of the machine. The latter relies on continuous monitoring of key components and assembly status, aiming to quantify risks and intervene in a timely manner: as an important component of the tower crane transmission system, the integrated closed planetary reducer will cause a sharp drop in power transmission efficiency if its gear meshing is abnormal, which may lead to jamming and shutdown in severe cases; while misalignment of multi-stage series shafts will introduce off-center loads and additional loads, inducing early failure of couplings and bearings, and ultimately threatening the overall structural safety of the transmission system.

[0028] Based on the aforementioned influences, this design constructs a dedicated state characterization module specifically for the tower crane's characteristics to achieve accurate diagnosis of balance, acceleration stability, reducer gear meshing status, and shaft alignment: The forward and reverse rotation balance characterization module extracts vibration characteristics during the uniform speed phase and quantifies the symmetry of the up and down strokes, thereby accurately assessing the system's balance state; the acceleration phase stability characterization module focuses on the start-stop transient process, diagnosing non-stationary behavior caused by inertial impact; the planetary reducer roller state characterization module, based on waterfall spectrum analysis, monitors gear meshing status in real time, identifying early wear and faults; the transmission system alignment characterization module accurately diagnoses axial deviation problems in multi-stage series shaft systems through multi-dimensional vibration characteristic analysis; finally, the comprehensive state assessment module achieves a quantitative judgment of the overall operating status of the tower crane by integrating the state indices of each subsystem from multiple dimensions. Its overall architecture design is as follows: Figure 3 As shown.

[0029] S102: Calculate the instantaneous effective value of the uniform vibration signal for each stroke cycle; based on the instantaneous effective value of the uniform vibration signal, determine the balance index of the tower pumping unit transmission system during the uniform operation phase in each stroke cycle.

[0030] Optionally, based on the instantaneous effective value of the uniform vibration signal, the balance index of the tower pumping unit transmission system during the uniform operation phase in each stroke cycle is calculated, specifically including: Based on the instantaneous effective value of the uniform vibration signal, the balance amplitude index and balance direction index of the tower pumping unit transmission system during the uniform operation phase in each stroke cycle are calculated using the following formula: ; ; In the formula, and These are the balance amplitude index and balance direction index of the tower pumping unit's drive system during the uniform speed operation phase of each stroke cycle. This refers to the instantaneous effective value of the transmission system of the tower pumping unit during the uniform speed operation phase of the upstroke; This represents the instantaneous effective value of the transmission system of the tower pumping unit during the uniform speed operation phase of the downstroke; Based on the balance amplitude index and balance direction index, the balance index of the tower pumping unit transmission system during the uniform speed operation phase in each stroke cycle is calculated using the following formula: SBI = BSI x sign(BDI) ; In the formula, SBI This refers to the balance index of the tower pumping unit's drive system during the uniform speed operation phase of each stroke cycle.

[0031] Among them, the Balance Symmetry Index (BSI) is used to measure the relative magnitude of the difference between the upstroke and downstroke vibrations; the Balance Direction Index (BDI) is used to characterize whether the system is "overbalanced or underbalanced", with a range of [−1,1], where a positive value indicates overbalance and a negative value indicates underbalance; the Signed Balance Index (SBI) combines the amplitude and direction into a single number for easier threshold judgment, with a value range of (−1,1), where a positive value indicates an overbalanced direction and the lower the symmetry (the greater the deviation from the ideal), and a negative value indicates an underbalanced direction and the greater the deviation.

[0032] Specifically, the tower-type pumping unit uses a motor to drive the drum in both forward and reverse rotation to complete the up and down strokes, while a counterweight provides mechanical compensation for the motion. This operating mechanism causes the vibration signal of the transmission system to exhibit characteristics of acceleration, constant speed, and deceleration phases simultaneously during the up and down strokes. Analysis of the vibration measurement points deployed on the transmission system and the calculated instantaneous effective value curves show that, under unbalanced conditions, there are significant differences in the vibration during the constant speed phases of the up and down strokes, such as... Figure 4 As shown.

[0033] To address the operational mechanism of tower-type pumping units, specifically the "motor's forward and reverse rotation drive and the mechanical compensation effect of the counterweight on eccentric forces," a method for characterizing the balance state based on vibration signals during the uniform speed segment is proposed. This method identifies the vibration during the stable uniform speed segment in both the upstroke and downstroke phases, calculates the RMS difference between the upstroke and downstroke phases, constructs a comprehensive balance index, and combines load information and historical trend analysis to quantify, determine the direction of, and classify the balance state of the pumping unit, thereby achieving accurate assessment and predictive diagnosis of the balance state.

[0034] To ensure the accuracy and stability of the balance calculation, the original vibration signal needs to be preprocessed. The preprocessing process is as follows: First, based on the crankshaft encoder signal, the upper and lower stroke cycles of the pumping unit are identified, and the vibration data is divided into stroke stages accordingly. Second, to eliminate transient vibration interference during acceleration and deceleration, vibration data from the uniform speed stages of the upper and lower strokes is specifically extracted as the core analysis object, thereby eliminating the influence of speed fluctuations. Finally, for the uniform speed segment vibration signal of each stroke, its instantaneous effective value (RMS) is calculated, and the RMS is normalized, denoted as RMS_up and RMS_down respectively. Further processing is performed according to radial and axial vibration channels to comprehensively capture vibration characteristics in different directions, ensuring data quality and consistency of characterization in subsequent analyses.

[0035] To comprehensively assess the operational balance of the pumping unit, multi-dimensional feature enhancement analysis is required based on the balance index. The specific process is as follows: First, calculate the characteristic indicators such as RMS vibration in the axial and radial directions for each stroke segment, construct the vibration difference matrix between the upper and lower strokes, and identify vibration bias patterns in different directions by comparing the degree of asymmetry in the axial and radial directions. Second, perform correlation analysis between the balance index and the pumping unit load parameters, statistically analyze the mean and standard deviation of the balance index under different load ranges, and plot the load-balance relationship curve or heat map to reveal the influence of load changes on vibration symmetry and identify whether there are load-dependent imbalance problems. Finally, smooth the balance index sequence over time or load, plot its trend graph in conjunction with historical data, analyze the rate of balance decline, and generate an early maintenance warning when the index is continuously below a set threshold or shows a significant downward trend. The fault classification is shown in Table 1.

[0036] Table 1 SBI Level Classification S103: Calculate the instantaneous effective value of the acceleration vibration signal for each stroke cycle, and plot the instantaneous effective value time series curve reflecting the instantaneous change law of vibration energy; extract the impact peak value, impact density, and curve gradient from the instantaneous effective value time series curve; determine the stability index of the tower pumping unit transmission system during the acceleration phase in each stroke cycle based on the change rate of the impact peak value, impact density, and curve gradient.

[0037] Optionally, based on the impact peak value, impact density, and curve gradient change rate, the stability index of the tower pumping unit drive system during the acceleration phase in each stroke cycle is calculated, specifically including: The normalized impact amplitude, normalized impact density, and normalized gradient variance of the tower pumping unit drive system during the acceleration phase in each stroke cycle are obtained by calculating the ratio of the peak impact value to the baseline instantaneous effective value, the ratio of the number of impacts per unit time to the baseline impact density, and the ratio of the curve gradient change rate to the baseline gradient variance. Based on the normalized impact amplitude, normalized impact density, and normalized gradient variance, the stability index of the tower pumping unit drive system during the acceleration phase in each stroke cycle is calculated using the following formula: ; In the formula, This refers to the stability index of the transmission system of a tower pumping unit during the acceleration phase of each stroke cycle. This is a normalized impact amplitude, reflecting the strength of the transient impact; The normalized impact density reflects the frequency of impacts during the acceleration phase. The normalized gradient variance reflects the smoothness or steepness of the time series curve of the instantaneous effective value. , and These are the impact intensity weight, impact frequency weight, and curve smoothness weight, respectively.

[0038] By assigning different weights to each indicator, such as the weight of impact intensity. Impact frequency weight Curve smoothness weight And full It is recommended to set the initial value to The stability index typically ranges from 0 to 1; the closer it is to 1, the smoother the acceleration phase and the weaker the impact characteristics.

[0039] Specifically, the tower-type pumping unit adopts a planetary reduction drum integrated transmission structure, and the up and down strokes are completed by the forward and reverse rotation of the motor. Due to the significant inertial effect during start-up, shutdown, and reversal, the reverse switching of the motor generates an impact load, causing nonlinear abrupt changes in the vibration signal during the acceleration phase. Analysis of the instantaneous effective value curve of the vibration shows that both the up and down strokes exhibit three stages: acceleration, constant speed, and deceleration. Furthermore, the instantaneous stability of the curve varies significantly with operating conditions, and the acceleration phase exhibits obvious transient impact characteristics, such as... Figure 5 As shown.

[0040] To address the inertial impact characteristics of the planetary reduction drum integrated transmission and motor during forward and reverse start-stop processes in tower-type pumping units, a method for characterizing acceleration stability based on transient impact characteristics during the acceleration phase is proposed. This method accurately identifies and extracts vibration signals during the acceleration phase in both the up and down strokes, calculates the RMS of the acceleration phase, and generates time-series curves. By quantifying multi-dimensional characteristics such as impact amplitude, impact density, and curve gradient changes, a comprehensive stability index is constructed. This index provides a quantitative assessment and graded early warning of the dynamic stability of the transmission system during start-stop and reversal processes, thereby achieving accurate diagnosis of acceleration stability.

[0041] To comprehensively and quantitatively evaluate the operational stability of the pumping unit during the acceleration phase, it is necessary to conduct a comprehensive analysis of the vibration signal from three dimensions: impact characteristics, time sequence distribution, and curve morphology, in order to reveal non-stationary behavior and potential mechanical imbalances from different sources.

[0042] Impact intensity analysis: Impact intensity measures the magnitude of transient energy release during acceleration. It is calculated by taking the ratio of the peak impact value to the baseline RMS (i.e., the normalized impact amplitude). The ratio can intuitively reflect the degree of energy mutation during the acceleration phase. A larger ratio indicates that the system has a significant impact during startup or load switching, which may be caused by clearances in transmission components, differences in mechanical inertia, or poor lubrication. Furthermore, the statistical distribution of the impact amplitude (such as mean, variance, and kurtosis) can be used to characterize the energy burst characteristics, providing a basis for identifying abnormal startup behavior.

[0043] Impact distribution analysis: Impact distribution reflects the uniformity and concentration of impact events along the acceleration time axis. This is achieved by calculating the ratio of the number of impacts per unit time to the baseline impact density (i.e., the normalized impact density). This allows for the analysis of the clustering and periodicity of impacts. If impact events are highly concentrated within a specific timeframe, it often indicates a mechanical imbalance or sudden torque change on the driving side. Further calculations can be made of the temporal standard deviation of impact occurrences or density curves based on sliding windows to quantify the dispersion of the distribution. Ideally, impact events should occur relatively uniformly during the acceleration phase, demonstrating high dynamic stability.

[0044] Curve characteristic analysis: Curve characteristics focus on the overall shape and local variation features of the instantaneous effective value curve. This is achieved by calculating the gradient rate of change and the normalized gradient variance. The gradient variance can quantitatively describe the smoothness and steepness of the curve. A larger gradient variance indicates drastic changes in vibration energy and poor stability, while a smaller gradient variance indicates a continuous and uniform vibration energy growth process. This feature can effectively reflect the energy transfer efficiency and mechanical response coordination during the acceleration phase. The fault classification for TSI is shown in Table 2.

[0045] Table 2 TSI Level Classification Table S104: Perform a sliding window short-time Fourier transform on the vibration signal of the bearing seats at both ends of the reduction drum to obtain the local spectrum and stack it in time to draw a three-dimensional time-frequency waterfall spectrum reflecting the dynamic evolution of vibration energy of the two-stage planetary reducer during acceleration, constant speed and deceleration; extract the characteristic frequency trajectory, sideband energy ratio and harmonic energy index from the three-dimensional time-frequency waterfall spectrum to determine the health index of the planetary reducer.

[0046] Optionally, before performing a sliding window short-time Fourier transform on the vibration signals of the bearing seats at both ends of the reduction drum, the method further includes: The rotational frequencies of the planet carrier and the sun gear in the two-stage planetary reducer are calculated using the following formulas: ; ; ; In the formula, The planet carrier rotation frequency, Input the rotational speed for the planetary carrier. The gear ratio of the reducer. The rotational speed of the sun gear. The rotational frequency of the sun gear; Based on the rotational frequency of the planet carrier and the rotational frequency of the sun gear, the meshing frequencies of the sun gear-planet gear and the planet gear-ring gear are calculated using the following formulas: ; ; In the formula, and These are the meshing frequencies of the sun gear-planet gear and the planet gear-ring gear, respectively. The number of teeth on the sun gear. The rotational frequency of the gear ring. This represents the number of teeth on the planetary gear.

[0047] : is an empirical weighting factor, and satisfies It is recommended to set the initial value to The health index ranges from 0 to 1; a higher value indicates that the reduction roller is working closer to its ideal state.

[0048] Optionally, the extraction of the characteristic frequency trajectory specifically includes: locating the energy extreme points of the planet carrier rotation frequency, the sun gear-planet gear meshing frequency, and the planet gear-ring gear meshing frequency in the three-dimensional time-frequency waterfall spectrum using a peak tracking algorithm; and interpolating the energy extreme points on the time axis of the three-dimensional time-frequency waterfall spectrum to obtain a continuous characteristic frequency trajectory.

[0049] Optionally, the extraction of the sideband energy proportion specifically includes: identifying the sideband energy on both sides of the sun gear-planet gear meshing frequency and the planet gear-ring gear meshing frequency in the three-dimensional time-frequency waterfall spectrum; calculating the ratio of the sideband energy to the main frequency energy to obtain the sideband energy proportion.

[0050] Optionally, the extraction of the harmonic energy index specifically includes: Specifically, the transmission system of a belt-wound tower crane adopts an integrated design of the drum and reducer. The drum houses a two-stage planetary reducer, resulting in a compact structure and multi-stage transmission. The inertial coupling and complex gear meshing of this multi-stage integrated structure make minor faults difficult to observe directly during operation. However, when the two-stage planetary reducer malfunctions, its vibration at a specific meshing frequency will significantly increase, thus reflecting abnormal gear meshing within the transmission system. For example... Figure 6 As shown.

[0051] To address the characteristics of the enclosed transmission structure of a tower-type pumping unit with an integrated planetary reducer and drum, a method for characterizing gear health status based on vibration waterfall spectrum is proposed. This method constructs a theoretical characteristic frequency template for a two-stage planetary reducer, utilizes time-frequency analysis to track the characteristic frequency trajectory and sideband structure under varying operating conditions, and establishes a health index that integrates frequency matching, sideband energy, and harmonic characteristics. This enables quantitative assessment and early fault warning of the gear meshing state inside the planetary reducer drum, effectively solving the technical challenges of fault feature extraction and accurate state determination in enclosed transmission structures.

[0052] First, a theoretical characteristic frequency template is established based on the specific structural parameters of the two-stage planetary reducer. To capture the dynamic behavior of the planetary reducer roller under varying operating conditions, this module uses the vibration signals from the bearing seats at both ends of the roller to generate a three-dimensional time-frequency waterfall spectrum of the vibration signal using a sliding window short-time Fourier transform. Then, through trajectory tracking and modulation analysis, depth features closely related to the mechanical state are extracted.

[0053] Time-frequency waterfall spectrum generation: The vibration signal is divided into a sliding window sequence of length L. A window function is applied to each window segment to suppress spectral leakage, and then a fast Fourier transform is performed to obtain its local spectrum. The above spectra are stacked in time order to construct a waterfall spectrum with time, frequency, and amplitude as three-dimensional coordinates, thus presenting a panoramic view of the dynamic evolution of vibration energy of the reducer during acceleration, constant speed, and deceleration, with particular attention to the vibration enhancement phenomenon at specific meshing frequencies.

[0054] Feature frequency trajectory extraction: Based on the waterfall spectrum, the peak tracking algorithm is used to accurately locate the planetary carrier rotation frequency. Frequency of gear meshing The energy extreme points near the theoretical characteristic frequencies are identified and correlated and interpolated on the time axis to form a continuous characteristic frequency trajectory. This trajectory directly reflects the drift of the characteristic frequency and its amplitude fluctuations. By calculating the statistics of the trajectory sequence, a quantitative basis is provided for the system's inertial changes and wear state.

[0055] Sideband Structure Identification: Sidebands are a direct manifestation of gear amplitude or frequency modulation effects, and their structure is closely related to the mechanical health. This module identifies sideband components on both sides of the meshing frequency and extracts key parameters such as bandwidth, spacing, and energy distribution. By calculating the ratio of sideband energy to main frequency energy, the system modulation intensity is accurately quantified, thereby diagnosing early anomalies caused by gear eccentricity, distributed faults, and load fluctuations.

[0056] Based on various characteristic indicators, the Gearbox Health Index (GHI) is defined, and its fault classification is shown in Table 3: Table 3. GHI Classification Table S105: Extract the octave amplitude characteristics, shaft phase relationship characteristics, and sideband modulation characteristics of the bearing housing of the reduction drum during each impact cycle during operation; determine the centering index of the fused axial and radial vibration information of the reduction drum based on the octave amplitude characteristics, shaft phase relationship characteristics, and sideband modulation characteristics.

[0057] Optionally, based on the harmonic amplitude characteristics, shaft phase relationship characteristics, and sideband modulation characteristics, the alignment index of the reduced roller's fused axial and radial vibration information is calculated, specifically including: The formula for calculating the normalized harmonic power ratio is: ; In the formula, This is the amplitude ratio of the harmonic energy to the frequency conversion energy, i.e., the harmonic amplitude characteristic. This is an adjustment coefficient used to control the saturation rate of this index; The formula for calculating the normalized phase difference is: ; In the formula, To normalize the phase difference, It is the absolute value of the phase difference between the motor end and the drum end in the axial vibration signal, i.e., the characteristic of the shaft system phase relationship; The formula for calculating the normalized sideband modulation depth is: ; In the formula, To normalize the sideband modulation depth, This is the ratio of the total energy of the sidebands to the energy of the main frequency. This is the adjustment coefficient; Based on the normalized harmonic power ratio, normalized phase difference, and normalized sideband modulation depth, the neutrality index is calculated using the following formula: ; In the formula, These are the weight coefficients, representing the contribution of each feature to the overall midpoint state, which must satisfy... .

[0058] It is recommended to set the initial value to . , This is an empirical constant used to map the original feature values ​​to a reasonable range. It is recommended to calibrate it using historical data, and the initial value can be set to... When the system is perfectly aligned, the AI ​​value is close to 1; if a significant deviation occurs, the AI ​​value tends to 0, indicating that there is structural misalignment.

[0059] Specifically, in the belt-wound tower crane drive system, the motor, tire coupling, and planetary reducer roller constitute a multi-stage series shaft system, with the reducer and roller forming a closed, integrated structure. This multi-stage closed layout is prone to misalignment faults when there are assembly or load deviations. The abnormally prominent 2X frequency component in the spectrum further verifies the possibility of misalignment faults in the system, such as... Figure 7 As shown.

[0060] To address the challenges of multi-stage series shafting layout and enclosed transmission structure in tower-type pumping units ("motor-tire coupling-planetary reduction drum"), a method for characterizing transmission system alignment based on multi-dimensional vibration features is proposed. This method extracts three types of features: the octave amplitude of the drum bearing housing, the shaft phase relationship, and the sideband modulation. It then constructs an alignment index that integrates axial and radial vibration information, enabling accurate identification and quantitative assessment of misalignment faults. This effectively solves the technical challenge of accurately determining the alignment status of tower-type pumping units under alternating forward and reverse rotation and variable load operating conditions due to the use of tire couplings and multi-stage series shafting structures.

[0061] Misalignment Feature Extraction: To accurately diagnose the alignment status of the transmission system, this module takes the vibration response of the planetary reducer roller as the core analysis object, and combines it with three-dimensional waterfall spectrum analysis to extract the following three types of fault features with clear physical meaning: Harmonic frequency amplitude characteristics: Under ideal alignment, vibration energy is mainly concentrated in the first harmonic (1X) and its lower harmonics. When misalignment occurs, the coupling will generate periodic additional stress, thereby exciting a significant high-harmonic frequency vibration response. Angular misalignment generates alternating axial bending moments, typically characterized by an abnormally prominent 2X component in axial vibration, often exceeding the 1X component. Parallel misalignment, due to periodic radial forces, is mainly manifested by a simultaneous and significant increase in both the 1X and 2X components in radial vibration. By quantifying the amplitude ratio, absolute energy, and evolution of the 1X, 2X, and even 3X components in the axial and radial directions, and their time-frequency evolution, it is possible not only to effectively identify the existence of alignment faults but also to preliminarily distinguish fault types and assess their severity.

[0062] Phase relationship characteristics: Phase information is a key criterion for distinguishing misalignment types. Through dual-channel synchronous acquisition, the phase of vibration signals from the motor output end and the drum input end at the same time and speed is compared. Angular misalignment causes symmetrical bending deformation of the shaft system, resulting in a stable phase difference of approximately 180 degrees between the axial vibration signals at both ends. Parallel misalignment causes parallel movement of the shaft system, manifested as a stable non-zero phase difference (e.g., 90 degrees) between the radial vibration signals at both ends. Accurate measurement of the steady-state phase difference in different directions provides a basis for determining the type of misalignment.

[0063] Sideband modulation characteristics: Periodic additional loads applied without alignment can significantly modulate high-frequency components such as gear meshing. Spectrally, this manifests as a family of sidebands spaced at rotational frequency (1X) or its harmonics (2X) on both sides of the gear meshing frequency (GMF). Axial excitation with angular misalignment typically produces sidebands spaced at 2X intervals; while radial excitation with parallel misalignment often produces sidebands spaced at 1X intervals. By analyzing the dominant spacing, symmetry, and the ratio of sideband energy to carrier energy (modulation depth) of the sidebands, the modulation intensity of the misalignment load on the transmission chain can be revealed, providing another dimension of frequency domain evidence for fault identification.

[0064] To comprehensively and quantitatively evaluate the alignment status of the transmission system, an Alignment Index (AI) is constructed. This index is obtained by normalizing and weighting three key characteristic parameters. The fault classification is shown in Table 4.

[0065] Table 4 AI Grading Standards S106: Based on the balance index, stability index, planetary reducer health index, and centering index, determine the comprehensive health index to characterize the operating status of the tower pumping unit transmission system.

[0066] Optionally, the formula for calculating the comprehensive health index is: ; In the formula, For the comprehensive health index, As a balance index, As a stability index, For the health index of the planetary decelerator, For the moderate index, the weighting coefficient 、 、 、 These are the balance index, stability index, planetary reducer health index, and their contribution weights to the moderate index, respectively. .

[0067] Specifically, existing monitoring solutions are mainly geared towards rotating machinery or beam pumping units, leaving a significant gap in their application to tower pumping units, a new type of equipment. Furthermore, existing condition monitoring systems mostly employ general methods, limited to independent analysis of single condition indicators. They fail to accurately model the complex system characteristics of tower pumping units, such as "planetary reduction drum integrated transmission, alternating forward and reverse operation, and multi-stage series shaft systems," and lack a matching multi-dimensional condition fusion evaluation mechanism. Therefore, they are unable to accurately reflect the overall operating status of the tower pumping unit.

[0068] In response to the unique operating mechanism of tower pumping units, which features planetary roller drive, variable load stroke, and multi-stage series shaft system, this module proposes a holistic health assessment and decision-making method based on multi-source vibration signals; designs a weighted adaptive fusion mechanism; establishes a multi-scale trend early warning system; and develops predictive maintenance and decision support processes, thereby quantifying the overall operating status of the tower pumping unit and achieving health risk early warning.

[0069] To comprehensively assess the overall health status of the transmission system, a Comprehensive Health Index (CHI) is constructed, which is calculated based on the weighted fusion of various specific indices.

[0070] Module Sensitivity: Based on the equipment's current main operating conditions, increase the weight of relevant modules. For example, under conditions of frequent start-stop cycles, increase the weight of the Stability Index (TSI). During the long-term uniform operation phase, the weight of the Balance Index (SBI) is increased. .

[0071] Equipment Importance: Based on FMEA (Failure Mode and Effects Analysis) principles, modules belonging to failure modes that could lead to serious consequences are assigned higher weights. For example, the weight of the Gearbox Health Index (GHI). It is usually set to the highest value because it has the highest downtime cost due to failure.

[0072] Additionally, the method includes establishing a multi-scale early warning mechanism for the tower pumping unit transmission system based on the comprehensive health index, balance index, stability index, planetary reducer health index, and centering index. This mechanism includes: issuing a yellow warning when any operating index of the tower pumping unit transmission system suddenly drops by 20% within a single operating cycle, prompting operators to check for sudden faults; issuing an orange warning when any operating index of the tower pumping unit transmission system shows a continuous downward trend for three consecutive monitoring cycles, indicating that the components of the tower pumping unit transmission system have entered an accelerated wear period; and issuing a red warning when the comprehensive health index of the tower pumping unit transmission system remains below a preset maintenance threshold, indicating that the equipment has entered an unhealthy state and requires immediate shutdown for maintenance.

[0073] Specifically, the system establishes a multi-scale early warning mechanism by tracking historical data sequences of the CHI and its sub-indices to achieve early fault detection. Short-term real-time warning: When any index suddenly drops by more than 20% within a single operating cycle, or experiences a significant abnormal shock, a yellow warning is immediately triggered, alerting operators to potential sudden faults. Medium-term progressive warning: When any index shows a continuous downward trend for three consecutive monitoring cycles (e.g., 3 days) (e.g., a slope less than -0.05 / cycle determined by linear regression), an orange warning is triggered, indicating that the component may be entering an accelerated wear period. Long-term threshold warning: When the CHI index or key sub-indices remain below preset maintenance thresholds (e.g., GHI < 0.70), a red warning is triggered, indicating that the equipment has entered an unhealthy state and requires immediate maintenance intervention.

[0074] This system achieves comprehensive analysis and precise quantification of the operating status of the tower pumping unit's drive system through a systematic analysis chain encompassing signal preprocessing, feature extraction, index calculation, and state fusion. Finally, leveraging a hierarchical visualization and reporting system, the analysis results are transformed into decision support information that is easy for field personnel to understand and operate, thus providing a complete and reliable technical solution for predictive maintenance and refined operation management of the equipment.

[0075] In summary, the lack of a dedicated characterization method for the transmission system of tower pumping units in the existing technology leads to a significant technical mismatch in its application to tower pumping units: key structural and operational characteristics of tower pumping units, such as planetary reduction drum integrated transmission, alternating forward and reverse operation, and dynamic processes under varying operating conditions, are not fully considered, making it difficult to accurately characterize the operating status of tower pumping units.

[0076] To address the aforementioned problems, this invention proposes a collaborative characterization and diagnosis method based on multi-source vibration signal analysis for tower-type pumping units. This method overcomes the limitations of traditional feature extraction and pattern recognition, and its advantages are reflected in the following aspects: A forward and reverse rotation balance characterization module extracts vibration signals from the constant-speed section during the up and down strokes of the tower-type pumping unit, quantifies the vibration symmetry of the up and down strokes, and constructs a comprehensive balance index to achieve accurate assessment of the actual balance state of the system; An acceleration phase stability characterization module extracts transient impact signals generated during the start-up, shutdown, and reversal processes of the tower-type pumping unit, analyzes the impact intensity, duration, and distribution characteristics, and achieves nonlinear vibration characterization of the transmission system during the acceleration phase. The system includes: quantitative characterization of sudden changes; a planetary reducer drum condition characterization module, which extracts specific meshing frequencies caused by early faults in the secondary planetary reducer inside the drum and matches them with theoretical meshing frequencies to achieve sensitive detection of gear meshing abnormalities; a transmission system alignment characterization module, which analyzes the angular, parallel, and compound misalignment faults that may occur in multi-stage series shaft systems during assembly or operation by combining vibration frequency harmonics, phase, and modulation characteristics to achieve accurate diagnosis of the type and degree of shaft deviation in the transmission system; and a comprehensive condition assessment module, which integrates the condition indices of various subsystems from multiple dimensions to construct a dedicated comprehensive evaluation index to achieve quantitative judgment of the overall operating status of the tower crane.

[0077] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this invention.

Claims

1. A method for characterizing the balanced operating state of a tower pumping unit transmission system, characterized in that, The method comprises the following steps: acquiring original vibration signals of a tower pumping unit transmission system in each stroke cycle during operation; and extracting uniform vibration signals, acceleration vibration signals, and vibration signals of bearing seats at both ends of a deceleration drum of the tower pumping unit transmission system from the original vibration signals in each stroke cycle; calculating instantaneous effective values of the uniform vibration signals in each stroke cycle; determining a balance degree index of the tower pumping unit transmission system in a uniform running stage in each stroke cycle according to the instantaneous effective values of the uniform vibration signals; calculating instantaneous effective values of the acceleration vibration signals in each stroke cycle, and drawing an instantaneous effective value time sequence curve reflecting instantaneous change rules of vibration energy; extracting an impact peak value, an impact density, and a curve gradient from the instantaneous effective value time sequence curve; and determining a smoothness index of the tower pumping unit transmission system in an acceleration running stage in each stroke cycle according to the impact peak value, the impact density, and a curve gradient change rate; performing sliding window short-time Fourier transform on the vibration signals of the bearing seats at both ends of the deceleration drum to obtain local frequency spectrums and stack the local frequency spectrums according to time, and drawing a three-dimensional time-frequency waterfall spectrum reflecting dynamic evolution of vibration energy of a secondary planetary reducer in the deceleration drum in the acceleration, uniform, and deceleration processes; and determining a planetary reducer health index from the three-dimensional time-frequency waterfall spectrum by extracting a characteristic frequency trajectory, an edge frequency band energy proportion, and a harmonic energy index. extracting frequency multiplication amplitude characteristics, shaft phase relationship characteristics, and edge frequency band modulation characteristics of the vibration signals of the bearing seats at both ends of the deceleration drum; and determining an alignment degree index of the deceleration drum fusing axial and radial vibration information according to the frequency multiplication amplitude characteristics, the shaft phase relationship characteristics, and the edge frequency band modulation characteristics; determining a comprehensive health index according to the balance degree index, the smoothness index, the planetary reducer health index, and the alignment degree index to represent a balanced running state of the tower pumping unit transmission system.

2. A method of characterizing a balanced operating condition of a tower drive system of an oil pumping machine as claimed in claim 1, characterized in that, The balance degree index of the tower pumping unit transmission system in the uniform running stage in each stroke cycle is calculated according to the instantaneous effective values of the uniform vibration signals, and specifically comprises the following steps: the balance amplitude index and the balance direction index of the tower pumping unit transmission system in the uniform running stage in each stroke cycle are calculated according to the instantaneous effective values of the uniform vibration signals, and the formulae are as follows: ； ； wherein and are the balance amplitude index and the balance direction index of the tower pumping unit drive system in the uniform running phase of each stroke cycle, respectively, is the instantaneous effective value of the tower pumping unit drive system in the uniform running phase of the upstroke process; is the instantaneous effective value of the tower pumping unit drive system in the uniform running phase of the downstroke process; the balance degree index of the tower pumping unit transmission system in the uniform running stage in each stroke cycle is calculated based on the balance amplitude index and the balance direction index, and the formula is as follows: SBI = BSI × sign (BDI) ； In the formula, SBI is the balance index of the tower pumping unit drive system in the uniform speed running stage of each stroke cycle.

3. A method of characterizing a balanced operating condition of a tower drive system of an oil pumping machine as claimed in claim 1, wherein, The smoothness index of the tower pumping unit transmission system in the acceleration running stage in each stroke cycle is calculated according to the impact peak value, the impact density, and the curve gradient change rate, and specifically comprises the following steps: the normalized impact amplitude, the normalized impact density, and the normalized gradient variance of the tower pumping unit transmission system in the acceleration running stage in each stroke cycle are obtained by respectively calculating the ratio of the impact peak value to the baseline instantaneous effective value, the ratio of the impact frequency in a unit time to the reference impact density, and the ratio of the curve gradient change rate to the reference gradient variance. According to the normalized impact amplitude, the normalized impact density and the normalized gradient variance, a smoothness index of the tower pumping unit transmission system in an acceleration running stage of each stroke cycle is calculated, and a formula is as follows: ； In the formula, is the smoothness index of the tower pumping unit drive system in the acceleration stage of each stroke cycle, is the normalized impact amplitude, reflecting the strength of the transient impact; is the normalized impact density, reflecting the frequency of the impact in the acceleration section; is the normalized gradient variance, reflecting the curve smoothness or steep change of the time sequence curve of the instantaneous effective value; , and are the impact strength weight, impact frequency weight, and curve smoothness weight, respectively.

4. A method of characterizing a balanced operating condition of a tower drive system of an oil pumping machine as claimed in claim 1, characterized in that, Before the vibration signal of the bearing seat at both ends of the speed reducer is subjected to the sliding window short-time Fourier transform, the method further includes: The planetary carrier rotating frequency and the sun gear rotating frequency of the two-stage planetary reducer are calculated respectively, and a formula is as follows: ； ； ； wherein is the rotational frequency of the planet carrier, is the input rotational speed of the planet carrier, is the transmission ratio of the reduction gear, is the rotational speed of the sun gear, is the rotational frequency of the sun gear; According to the planetary carrier rotating frequency and the sun gear rotating frequency, the sun gear-planet wheel meshing frequency and the planet wheel-ring gear meshing frequency are calculated, and a formula is as follows: ； ； wherein and are the sun-planet meshing frequency and the planet-ring gear meshing frequency, respectively, is the number of sun gear teeth, is the ring gear rotational frequency, is the number of planet gear teeth.

5. A method of characterizing the balanced operating condition of a tower drive system of an oil pumping machine according to claim 1, characterized in that, The feature frequency trajectory is extracted, and the extraction specifically includes: The peak tracking algorithm is used to locate energy extreme points of the planetary carrier rotating frequency, the sun gear-planet wheel meshing frequency and the planet wheel-ring gear meshing frequency in the three-dimensional time-frequency cascade spectrum; The energy extreme points are interpolated on a time axis of the three-dimensional time-frequency cascade spectrum to obtain a continuous feature frequency trajectory.

6. A method of characterizing the balanced operating condition of a tower drive system of an oil pumping machine as defined in claim 1, characterized in that, The edge band energy proportion is extracted, and the extraction specifically includes: The edge band energy on both sides of the sun gear-planet wheel meshing frequency and the planet wheel-ring gear meshing frequency in the three-dimensional time-frequency cascade spectrum is identified; The ratio of the edge band energy to the main frequency energy is calculated to obtain the edge band energy proportion.

7. A method of characterizing the balanced operating condition of a tower drive system of an oil pumping machine as defined in claim 1, characterized in that, The harmonic energy index is extracted, and the extraction specifically includes: The vibration signal of the bearing seat at both ends of the speed reducer in the three-dimensional time-frequency cascade spectrum is converted to the frequency domain by the Fourier transform, the fundamental wave and each single harmonic are separated, and the frequency and the amplitude of the vibration signal are extracted; According to the relationship that energy is proportional to the square of the amplitude, the single harmonic energy, the total harmonic energy and the fundamental wave energy are determined; The ratio of each single harmonic energy to the total harmonic energy is weighted and summed to obtain the harmonic energy index for evaluating the energy distribution characteristics.

8. A method of characterizing the balanced operating condition of a tower drive system of an oil pumping machine as defined in claim 1, characterized in that, According to the frequency multiplication amplitude feature, the shafting phase relationship feature and the edge band modulation feature, a centering degree index of the speed reducer that fuses axial and radial vibration information is calculated, and the calculation specifically includes: The normalized frequency multiplication energy ratio is calculated, and a formula is as follows: ； wherein is the amplitude ratio of the frequency-doubled energy to the frequency-converted energy, i.e. the frequency-doubled amplitude characteristic, is a regulation factor for controlling the saturation speed of the index; The normalized phase difference is calculated, and a formula is as follows: ； In the formula, is the normalized phase difference, is the absolute value of the phase difference between the motor end and the drum end in the axial vibration signal, i.e., the shaft phase relationship feature; The normalized edge band modulation depth is calculated, and a formula is as follows: ； wherein is the normalized sideband modulation depth, is the ratio of the total sideband energy to the carrier energy, is the adjustment factor; Based on the normalized frequency multiplication energy ratio, the normalized phase difference and the normalized edge band modulation depth, the centering degree index is calculated, and a formula is as follows: ； In the formula, are weight coefficients respectively, representing the contribution of each feature to the overall centering state, and need to satisfy .

9. A method of characterizing the balanced operating condition of a tower drive system of an oil pumping machine as defined in claim 1, characterized in that, The calculation formula of the comprehensive health index is as follows: ； In the formula, is a health comprehensive index, is a balance degree index, is a stability index, is a planetary reducer health index, is a centering degree index, and the weight coefficient 、 、 、 respectively are the contribution weights of the balance degree index, the stability index, the planetary reducer health index and the centering degree index, and .

10. A method of characterizing a balanced operating condition of a tower drive system of an oil pumping machine as defined in claim 1, wherein, The method further includes: Based on the comprehensive health index, the balance degree index, the smoothness index, the planetary reducer health index and the centering degree index, a multi-scale early warning mechanism of the tower pumping unit transmission system is established, and the establishment includes: When any running index of the tower pumping unit transmission system suddenly drops by 20% in a single running cycle, a yellow early warning is triggered, prompting an operator to check the sudden failure; When any running index of the tower pumping unit transmission system shows a continuous downward trend for 3 consecutive monitoring cycles, an orange early warning is triggered, indicating that the components of the tower pumping unit transmission system enter an accelerated wear period; When the comprehensive health index of the tower pumping unit transmission system continuously drops below a preset maintenance threshold, a red early warning is triggered, indicating that the equipment has entered an unhealthy state and needs to be immediately shut down for maintenance.

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