A method and system for evaluating the stability of a work platform of an aerial work platform

Abstract

A kind of aerial work platform stability evaluation method and system, device and system of high-altitude operation vehicle, including the following steps: synchronously obtaining the first vibration signal of vehicle chassis first monitoring point, the second vibration signal of second monitoring point on work platform and obtaining the working condition data of work platform;Based on the first vibration signal and the second vibration signal, the real-time transmission relationship between the first monitoring point and the second monitoring point is obtained;Based on the working condition data and the standard transmission relationship, the reference transmission relationship between the first monitoring point and the second monitoring point under the current working condition is obtained;The deviation of both is calculated;According to the deviation, the structural stability of work platform is evaluated.By real-time monitoring and comparing with the health benchmark related to working condition, normal vibration caused by external excitation and abnormal vibration caused by structural damage are distinguished.Misreporting caused by external environment or chassis vibration transmission is avoided, and the effectiveness of high-altitude work platform structural stability evaluation is improved.

Description

Technical Field

[0001] This application relates to the field of work platform status testing and diagnosis technology, specifically to a method and system for evaluating the stability of an aerial work platform. Background Technology

[0002] Aerial work platforms are widely used in construction, equipment installation, power maintenance, and landscaping, serving as specialized vehicles for lifting personnel, tools, and materials to heights for work. The structural safety of the work platform is a critical factor affecting the safety of both equipment and personnel. During long-term use, the mechanical structure of the work platform (such as the boom, connecting hinges, and platform base) may experience stiffness degradation, damping changes, or localized damage due to fatigue loads, accidental collisions, or loose fasteners. If these structural deteriorations are not detected in time, they can lead to serious instability accidents.

[0003] Currently, several technical solutions have been proposed for monitoring the structural condition of aerial work platforms. One common approach involves installing accelerometers at the end of the platform to directly measure the vibration amplitude or peak acceleration during operation and comparing it to a preset threshold. If the vibration amplitude exceeds the threshold, the platform is deemed to be at risk of instability. Another approach incorporates frequency domain analysis, assessing the structural condition by monitoring energy changes or dominant frequency drift in the platform's vibration signals within a specific frequency band.

[0004] However, during actual operation, the working platform of an aerial work platform may be subjected to vibration excitation from the vehicle chassis and the surrounding environment. For example, when the vehicle is traveling or moving between sites, the chassis may traverse uneven roads, speed bumps, or potholes, generating strong vibrations that are transmitted to the working platform through the boom structure, causing the platform's end-effector sensors to detect significant vibration signals. Alternatively, when there are vibration sources in the surrounding construction environment, such as pile drivers, hydraulic breakers, or heavy transport vehicles operating in nearby areas, their vibrations are transmitted through the ground to the aerial work platform's chassis and boom, also causing significant vibration responses at the platform's end. In addition, when the vehicle's own power system is operating, engine idling and hydraulic pump start-stop operations also generate continuous vibrations with certain frequency characteristics, which are transmitted to the platform through the structure. In these scenarios, a significant portion of the vibration signals detected by the platform's end-effector sensors originate from the transmission of external excitations, rather than from abnormal changes in the platform's own structural state. Traditional evaluation methods based on absolute vibration amplitude or fixed thresholds often misjudge these normal vibration responses caused by external excitations as platform instability, leading to frequent false alarms and severely impacting the equipment's normal operating efficiency and operator confidence. Summary of the Invention

[0005] This application provides a method and system for evaluating the stability of an aerial work platform, which can solve the technical problems existing in the above-mentioned related technologies.

[0006] In a first aspect, embodiments of this application provide a method for evaluating the stability of an aerial work platform, employing the following technical solution:

[0007] A method for evaluating the stability of an aerial work platform includes the following steps:

[0008] The system simultaneously acquires the first vibration signal from the first monitoring point on the vehicle chassis, the second vibration signal from the second monitoring point on the work platform, and the working condition data of the work platform; wherein, the working condition data includes the load weight of the work platform and the attitude data of the work platform.

[0009] Based on the first vibration signal and the second vibration signal, a real-time transmission relationship reflecting the vibration transmission characteristics between the first monitoring point and the second monitoring point is obtained;

[0010] Based on the aforementioned working condition data and standard transmission relationship, a reference transmission relationship reflecting the vibration transmission characteristics between the first monitoring point and the second monitoring point under the current working condition is obtained.

[0011] Calculate the deviation between the real-time transfer relationship and the reference transfer relationship;

[0012] The structural stability of the work platform is evaluated based on the deviation.

[0013] In conjunction with the first aspect, in one embodiment, obtaining the real-time transmission relationship reflecting the vibration transmission characteristics between the first monitoring point and the second monitoring point based on the first vibration signal and the second vibration signal includes the following steps:

[0014] Based on the first vibration signal and the second vibration signal, determine whether there is an active local vibration source on the work platform;

[0015] If it does not exist, then based on the ratio of the first vibration signal and the second vibration signal, a real-time transmission relationship reflecting the transmission characteristics of the vibration signal is obtained;

[0016] If present, the first vibration signal and the second vibration signal are combined and processed based on a preset local vibration source suppression analysis model to obtain a real-time transmission relationship reflecting the vibration transmission characteristics between the first monitoring point and the second monitoring point after suppressing the local vibration source interference.

[0017] In conjunction with the first aspect, in one embodiment, the local vibration source suppression analysis model obtains the real-time transmission relationship by combining the first vibration signal and the second vibration signal, including the following steps:

[0018] Based on the first vibration signal and the second vibration signal, determine the first self-power spectral density of the first vibration signal, the second self-power spectral density of the second vibration signal, and the complex cross-power spectral density including the common energy intensity information and phase difference information of the first vibration signal and the second vibration signal;

[0019] Based on the first self-power spectral density, the second self-power spectral density, the complex cross-power spectral density, and the coherence between the first vibration signal and the second vibration signal, the real-time transmission relationship after interference suppression is obtained.

[0020] In conjunction with the first aspect, in one embodiment, the real-time transmission relationship after interference suppression is obtained based on the first self-power spectral density, the second self-power spectral density, the complex cross-power spectral density, and the coherence between the first vibration signal and the second vibration signal. The expression for the real-time transmission relationship is as follows:

[0021] H_robust(f) = G_yz(f) / (G_yy(f) - α * |G_yz(f)|)

[0022] Wherein, G_yy(f) is the first self-power spectral density; G_yz(f) is the complex cross-power spectral density; α is an adaptive adjustment factor obtained based on the coherence between the first vibration signal and the second vibration signal, and 0 ≤ α < 1.

[0023] In conjunction with the first aspect, in one implementation, the adaptive adjustment factor α is determined through the following steps:

[0024] Calculate the coherence function γ²(f) between the first vibration signal and the second vibration signal:

[0025] γ²(f) = |G_yz(f)| 2 / (G_yy(f) * G_zz(f)); where G_yy(f) is the first auto-power spectral density; G_yz(f) is the complex cross-power spectral density; and G_zz(f) is the second auto-power spectral density.

[0026] Take the minimum value of the coherence function, coh_min, and calculate the adaptive adjustment factor based on the following formula:

[0027] α = 1 - coh_min.

[0028] In conjunction with the first aspect, in one embodiment, determining whether there is an active local vibration source on the work platform based on the first vibration signal and the second vibration signal includes the following steps:

[0029] At a known characteristic frequency of the local vibration equipment on the work platform, determine the coherence function value of the first vibration signal and the second vibration signal;

[0030] If the coherence function value is lower than a preset first threshold, it is determined that there is an active local vibration source interference.

[0031] In conjunction with the first aspect, in one implementation, calculating the deviation between the real-time transfer relationship and the reference transfer relationship includes:

[0032] Within a preset neighborhood frequency band [fn(1-k), fn(1+k)] centered on the first-order natural frequency fn of the work platform structure, the root mean square error of the amplitude spectrum between the real-time transfer relationship and the reference transfer relationship is calculated as the deviation.

[0033] Wherein, k is a preset nominal proportional coefficient, with a value range of 0.15≤k≤0.3; the neighborhood frequency band covers the resonant sensitive area of ​​the structural transmission characteristics, so that the deviation mainly reflects the change in structural state rather than the change in chassis excitation amplitude.

[0034] In conjunction with the first aspect, in one implementation, obtaining the reference transmission relationship reflecting the vibration transmission characteristics between the first monitoring point and the second monitoring point under the current operating conditions based on the operating condition data and the standard transmission relationship includes:

[0035] Obtain a calibration domain, which contains a set of standard transfer relationships measured by discrete calibration points corresponding to various working conditions when the work platform is in a healthy standard state.

[0036] If the current operating condition data falls within the calibration domain, a reference transmission relationship reflecting the vibration transmission characteristics between the first monitoring point and the second monitoring point can be obtained through interpolation between the calibration points.

[0037] In conjunction with the first aspect, in one implementation, the standard transitive relation set is pre-defined in the following manner:

[0038] When the operating platform is in a healthy standard state and within the calibration domain, calibration points corresponding to various discrete working conditions are selected, and the chassis is actively excited or a measurable excitation is applied at each calibration point. The first vibration signal and the second vibration signal are collected simultaneously, and the standard transmission relationship under the corresponding working conditions is calculated.

[0039] Secondly, embodiments of this application provide a stability evaluation system for the working platform of an aerial work vehicle, employing the following technical solution:

[0040] A stability assessment system for the working platform of an aerial work vehicle, comprising:

[0041] The acquisition module is configured to simultaneously acquire a first vibration signal from a first monitoring point on the vehicle chassis, a second vibration signal from a second monitoring point on the work platform, and working condition data of the work platform; wherein the working condition data includes the load weight of the work platform and the attitude data of the work platform.

[0042] The first calculation module is configured to obtain a real-time transmission relationship reflecting the vibration transmission characteristics between the first monitoring point and the second monitoring point based on the first vibration signal and the second vibration signal.

[0043] The second calculation module is configured to obtain a reference transmission relationship that reflects the vibration transmission characteristics between the first monitoring point and the second monitoring point under the current working conditions, based on the working condition data and the standard transmission relationship.

[0044] A stability assessment module is configured to calculate the deviation between the real-time transmission relationship and the reference transmission relationship; and to assess the structural stability of the operating platform based on the deviation.

[0045] The beneficial effects of the technical solutions provided in this application include:

[0046] This application provides a method and system for evaluating the stability of an aerial work platform. By deploying vibration sensors at a first and second monitoring point, and weighing and angle sensors on the platform, it achieves real-time acquisition of multi-source information on vibration transmission path, load weight, and working posture. Furthermore, by introducing vibration transmission characteristic analysis, it avoids directly comparing the amplitude of the collected vibration signals. Instead, it compares the difference between the currently measured structural transmission characteristics (real-time transmission relationship) and the structural transmission characteristics expected under the same working conditions in a healthy state (reference transmission relationship) to determine whether the platform structure has undergone abnormal changes. This separates changes in external excitation from changes in structural state, effectively overcoming the technical problem of misjudgment caused by chassis or environmental vibration interference in traditional methods. Moreover, since early changes in structural state will first manifest in the transmission characteristics, this invention, through real-time monitoring of transmission characteristic drift by vibration sensors at two locations, can detect early signs of structural anomalies before the vibration amplitude increases significantly, achieving early warning. Attached Figure Description

[0047] Figure 1This is a flowchart illustrating an embodiment of the stability assessment method for the working platform of the aerial work vehicle of this application;

[0048] Figure 2 This is a schematic diagram of the functional modules of an embodiment of the stability assessment system for the working platform of the aerial work vehicle of this application. Detailed Implementation

[0049] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0050] In actual operation, the working platform of existing aerial work platforms is frequently subjected to vibration excitation from the vehicle chassis and the external environment. These vibrations are transmitted to the platform through the structure, causing the end effector sensors to detect large amplitude signals. However, most of these signals originate from external excitation and are not due to platform structural abnormalities. Existing assessment methods based on absolute vibration amplitude or fixed thresholds are prone to misinterpreting normal vibrations as platform instability, triggering false alarms, and affecting operational efficiency and operator confidence.

[0051] In response, this application proposes a method for evaluating the stability of an aerial work platform, comprising the following steps:

[0052] S100, synchronously acquire the first vibration signal of the first monitoring point of the vehicle chassis, the second vibration signal of the second monitoring point on the work platform, and acquire the working condition data of the work platform; wherein, the working condition data includes the load weight of the work platform and the attitude data of the work platform;

[0053] The first monitoring point is set as a vibration signal acquisition location on the vehicle chassis to obtain vibration input information from the chassis. This point is typically selected at the connection between the boom and the chassis to reflect the excitation transmitted to the superstructure.

[0054] The second monitoring point was set as a vibration signal acquisition location on the work platform to obtain vibration response information of the work platform. This point is usually selected at the end of the work platform away from the chassis to reflect the vibration state of the platform;

[0055] The operating data includes the load weight of the work platform and the platform's attitude data. Vibration signals are acquired by installing vibration sensors on both the vehicle chassis and the work platform. For example, the vibration sensors can be configured to collect vibration data at a specific sampling frequency and duration. The load weight in the operating data can be obtained using load cells deployed on the work platform, while the attitude data is acquired using angle sensors.

[0056] S200. Based on the first vibration signal and the second vibration signal, a real-time transmission relationship reflecting the vibration transmission characteristics between the first monitoring point and the second monitoring point is obtained.

[0057] This step involves extracting the vibration transmission characteristics from the chassis to the platform end from the measured vibration signals in real time, i.e., the real-time transmission relationship. This transmission relationship is essentially a frequency-dependent function that describes how vibration energy is transmitted through the structural path as the frequency changes. Its form mainly depends on the inherent properties of the structure itself, such as stiffness, damping, and mass distribution. Therefore, regardless of the strength of the chassis vibration, as long as the structure itself remains unchanged, this transmission relationship should remain relatively stable. Therefore, using it as the object of subsequent comparison can effectively avoid misjudgments caused by fluctuations in chassis vibration intensity (such as when the vehicle travels over uneven roads or engine speed changes).

[0058] S300. Based on the working condition data and standard transfer relationship, a reference transfer relationship is obtained that reflects the vibration transfer characteristics between the first monitoring point and the second monitoring point under the current working condition.

[0059] The standard transfer relationship is a set of benchmark data calibrated or calculated under healthy conditions for different operating conditions. This relationship represents the structure between the first monitoring point and the second monitoring point, that is, the dynamic response of the working platform structure under ideal conditions. In one implementation, a set of standard transfer relationships under different load weights and attitudes can be pre-stored. When the current operating condition data is obtained, the standard transfer relationship closest to the current operating condition is directly looked up as the reference transfer relationship.

[0060] S400, Calculate the deviation between the real-time transfer relationship and the reference transfer relationship;

[0061] Deviation is a quantitative indicator that comprehensively reflects the degree of drift of the structural state relative to a healthy baseline. When the structure is in a healthy state, the real-time transfer relationship and the reference transfer relationship should be basically consistent, with a small deviation. When the structure experiences anomalies such as stiffness degradation, loose connections, or damping changes, the real-time transfer relationship will change, leading to an increase in deviation. Therefore, the magnitude of the deviation directly reflects the degree of anomaly in the structural state. In one implementation, the absolute values ​​of the amplitude differences between the real-time transfer relationship and the reference transfer relationship in the frequency domain can be calculated, or the calculation can be based on the amplitude differences between the two at different frequency points.

[0062] S500: Evaluate the structural stability of the work platform based on the degree of deviation.

[0063] Specifically, the assessment can be based on preset thresholds. For example, when the deviation exceeds the threshold, the operating platform is deemed to have a risk of structural instability. Alternatively, structural stability can be classified into levels based on the magnitude of the deviation, such as "healthy," "abnormal," and "severely abnormal."

[0064] Ultimately, this application achieves real-time acquisition of multi-source information on vibration transmission path, load weight, and working posture by deploying vibration sensors at the first and second monitoring points, and weighing and angle sensors on the working platform. Furthermore, by introducing vibration transmission characteristic analysis, it avoids directly comparing the amplitude of the acquired vibration signals. Instead, it compares the difference between the currently measured structural transmission characteristics (real-time transmission relationship) and the structural transmission characteristics expected under the same working conditions in a healthy state (reference transmission relationship) to determine whether the platform structure has undergone abnormal changes. This separates changes in external excitation from changes in structural state, effectively overcoming the technical challenge of misjudgment caused by chassis or environmental vibration interference in traditional methods. Moreover, since early changes in structural state will first manifest in transmission characteristics, this invention, through real-time monitoring of transmission characteristic drift by vibration sensors at two locations, can detect early signs of structural anomalies before the vibration amplitude increases significantly, achieving early warning.

[0065] Furthermore, in some embodiments, step S200, obtaining a real-time transmission relationship reflecting the vibration transmission characteristics between the first monitoring point and the second monitoring point based on the first vibration signal and the second vibration signal, includes the following steps:

[0066] S210. Based on the first vibration signal and the second vibration signal, determine whether there is an active local vibration source on the work platform;

[0067] Specifically, during actual operation, the work platform may be equipped with local vibration devices such as hydraulic power units, generators, fans, and cutting mechanisms. These devices generate significant vibrations during operation, which are transmitted to the second monitoring point through the platform structure and may also be transmitted back to the first monitoring point through structural connections, causing signal contamination at both monitoring points. This step, by jointly analyzing the two vibration signals, determines whether there is active local vibration source interference at the current moment. This allows for efficient and concise estimation of subsequent transmission relationships when there is no local vibration interference, and enables selective processing when interference is present, ensuring the accuracy of the final calculation results and achieving condition awareness and adaptive decision-making.

[0068] S220. If it does not exist, based on the ratio of the first vibration signal and the second vibration signal, a real-time transmission relationship reflecting the transmission characteristics of the vibration signal is obtained.

[0069] When it is confirmed that there are no active local vibration sources on the work platform, it indicates that the second vibration signal is mainly transmitted from the first vibration signal through the structure. That is, the signals at both monitoring points are primarily driven by chassis excitation, and the signal quality is good. In this case, a classic transfer function estimation method can be used, such as calculating the ratio of the self-spectrum and cross-spectrum, to quickly and accurately obtain the real-time transfer relationship. This classic ratio method, which involves low computational cost and clear physical meaning under interference-free conditions, ensures the accuracy of the transfer relationship estimation while avoiding unnecessary computational overhead, thus benefiting the system's real-time response and energy consumption control.

[0070] Specifically, in this embodiment, the transfer function in the frequency domain is obtained by dividing the Fourier transform of the second vibration signal by the Fourier transform of the first vibration signal.

[0071] H(f) = Y(f) / X(f)

[0072] Where Y(f) and X(f) are the frequency domain representations of the second vibration signal and the first vibration signal, respectively. Alternatively, in other embodiments, a method based on power spectral density can be used, for example, by calculating the ratio of the cross power spectral density G_xy(f) to the input self power spectral density G_xx(f) to obtain the transfer function, i.e., H(f) = G_xy(f) / G_xx(f).

[0073] S230. If present, the first vibration signal and the second vibration signal are combined and processed based on a preset local vibration source suppression analysis model to obtain a real-time transmission relationship reflecting the vibration transmission characteristics between the first monitoring point and the second monitoring point after suppressing the local vibration source interference.

[0074] If the judgment result indicates the presence of an active local vibration source, it means that the signals from both monitoring points are contaminated by the local vibration source. In this case, if the classic ratio method is still used, the estimation result will be distorted and cannot reflect the actual structural transmission path from the chassis to the platform. Therefore, based on a preset local vibration source suppression analysis model, the first and second vibration signals are combined and processed to obtain a real-time transmission relationship reflecting the vibration transmission characteristics between the first and second monitoring points after suppressing the interference from the local vibration source.

[0075] The local vibration source suppression analysis model used aims to separate the components caused by local vibration sources from the mixed second vibration signal, thereby extracting the pure response that reflects only the transmission from the chassis to the platform structure. One feasible implementation is to employ adaptive filtering technology. Using the first vibration signal as the reference input and the second vibration signal as the desired output, an adaptive algorithm (such as the Least Mean Square (LMS) algorithm) is used to construct a filter that can estimate and eliminate local vibration components in the second vibration signal that are unrelated to the first vibration signal.

[0076] Through the above technical solutions, the method can automatically identify whether there is local vibration source interference in the current working condition, and select the most suitable transmission relationship estimation strategy accordingly. It can achieve the use of lightweight algorithms in interference-free scenarios to save computing resources, and the use of anti-interference analysis models in interference scenarios to ensure the estimation accuracy of the final real-time transmission relationship. This makes the method suitable for real-time monitoring systems and able to cope with complex working environments.

[0077] Furthermore, in some embodiments, this application further proposes a process for obtaining the real-time transmission relationship by combining the first vibration signal and the second vibration signal using a local vibration source suppression analysis model, including:

[0078] S231. Based on the first vibration signal and the second vibration signal, determine the first self-power spectral density of the first vibration signal, the second self-power spectral density of the second vibration signal, and the complex cross-power spectral density containing the common energy intensity information and phase difference information of the first vibration signal and the second vibration signal.

[0079] Specifically, the first and second self-power spectral densities are real functions that describe the energy distribution of the first and second vibration signals at various frequency points, respectively. They characterize the energy features of the excitation sources at the first monitoring point on the vehicle chassis and the second monitoring point at the end of the work platform. The complex cross-power spectral density is a complex function whose amplitude reflects the common energy intensity of the first and second vibration signals at various frequency points, and whose phase reflects the phase difference between them. The complex cross-spectral density carries the path information of vibration transmission from the chassis to the end of the platform, thus it can capture the dynamic correlation between chassis excitation and the response at the second monitoring point of the work platform.

[0080] By establishing the two spectral quantities mentioned above, the complex vibration signal relationship in the time domain is transformed into a clear spectral representation in the frequency domain. The self-spectrum provides information on the distribution of input energy, while the cross-spectrum provides information on the transmission process from input to output. Together, they form the data foundation for subsequent anti-interference processing. In particular, the complex cross-spectrum preserves phase information, enabling the estimated transmission relationship to simultaneously include both amplitude-frequency and phase-frequency characteristics, resulting in more complete information.

[0081] Methods for determining these spectral densities may include, but are not limited to, segmenting and windowing the acquired first and second vibration signals, and then performing a Fast Fourier Transform (FFT) to obtain their respective spectra. For example, the first self-power spectral density can be obtained by multiplying the spectrum of the first vibration signal by its conjugate spectrum and taking the average. The complex cross-power spectral density can be obtained by multiplying the spectrum of the first vibration signal by its conjugate spectrum and taking the average.

[0082] S232. Based on the first self-power spectral density, the second self-power spectral density, the complex cross-power spectral density, and the coherence between the first vibration signal and the second vibration signal, the real-time transmission relationship after interference suppression is obtained.

[0083] Specifically, in this embodiment, the relational expression is transmitted in real time as follows:

[0084] H_robust(f) = G_yz(f) / (G_yy(f) - α * |G_yz(f)|)

[0085] Where G_yy(f) is the first self-power spectral density;

[0086] G_yz(f) is the complex cross-power spectral density;

[0087] α is an adaptive adjustment factor obtained based on the coherence between the first vibration signal and the second vibration signal, and 0 ≤ α < 1.

[0088] Regarding the above expression, it should be noted that in classic single-input single-output transfer function estimation, the commonly used H1 estimator is:

[0089] H1(f) = Gyy(f) / Gyz(f)

[0090] The estimator implicitly assumes that the input signal (i.e., the first vibration signal) is pure, and all input energy comes from the excitation of the system under test. However, in the scenario addressed by this invention, when there is an active local vibration source on the work platform, the vibration of this local source will not only be directly superimposed on the second vibration signal (platform end), but will also be transmitted back to the first monitoring point (chassis) through structural connections, causing the first vibration signal to also contain vibration components related to the local source. At this time, the self-power spectral density Gyy(f) of the first vibration signal contains some spurious input energy, that is, energy that should belong to local source interference rather than chassis excitation. If the classic H1 estimator is still used, the denominator Gyy(f) will be raised by spurious energy, which will lead to an underestimation of the amplitude of the transfer function and a distortion of the resonance peak position, thus failing to reflect the true structural transfer characteristics. To address this problem, this embodiment proposes a structured denominator correction method. The core idea is to subtract a portion of the energy that is strongly linearly correlated with the output signal from the total input energy Gyy(f). In the "bidirectional pollution" scenario, this portion of energy mainly corresponds to the local vibration source energy that pollutes the first vibration signal through the reverse transmission path. Specifically:

[0091] The molecule Gyz(f) retains the classical cross-power spectral density. It is a complex number that contains both amplitude and phase information. It carries the path information of vibrations from the first monitoring point to the second monitoring point and is the core source of information for the transfer function.

[0092] The denominator correction term -α*|Gyz(f)|: |Gyz(f)| is the modulus of the cross-power spectral density, which quantifies the common energy intensity of the first and second vibration signals at frequency f. When a local vibration source simultaneously contaminates both signals, a significant portion of this common energy originates from the local source rather than the chassis excitation. By subtracting α*|Gyz(f)|, it is equivalent to deducting a portion of spurious energy strongly correlated with the output from the total input energy, thus making the denominator closer to the true chassis excitation energy.

[0093] The adaptive adjustment factor α, ranging from 0 to 1, controls the strength of the correction. When α = 0, the formula degenerates into the classic H1 estimator, suitable for scenarios without local vibration source interference. When α approaches 1, it indicates that the system believes the strong correlation between the first and second vibration signals is mainly caused by common interference, thus subtracting most of the cross-spectral correlated energy from the input energy to achieve strong suppression. The specific value of α is further determined by the coherence between the first and second vibration signals, achieving a match between the suppression strength and the interference intensity.

[0094] Ultimately, through the above expression, in the scenario where the local vibration source simultaneously contaminates the signals of two monitoring points, this formula can significantly reduce the impact of interference on the transfer function estimation results, making the estimated transfer relationship closer to the actual structural transfer characteristics from the chassis to the platform. On the other hand, through the α parameter, this formula achieves a continuous and smooth transition of the suppression process, rather than a hard mode switch, enabling the method to adapt to continuous changes in interference intensity and avoiding jumps and instabilities caused by threshold switching.

[0095] Furthermore, in some embodiments, the adaptive adjustment factor α is determined through the following steps:

[0096] Calculate the coherence function γ between the first vibration signal and the second vibration signal. 2 (f):

[0097] γ 2 (f) = |G_yz(f)| 2 / (G_yy(f) * G_zz(f));

[0098] Wherein, G_yy(f) is the first self-power spectral density; G_yz(f) is the complex cross-power spectral density; and G_zz(f) is the second self-power spectral density.

[0099] The coherence function is a dimensionless index between 0 and 1. It measures what proportion of the power of the second vibration signal Z(t) at frequency f can be explained by the first vibration signal Y(t) through a linear system. When the coherence function is close to 1, it indicates that the two signals have a high linear correlation at that frequency, the vibration transmission path is clear, and the interference from local vibration sources is weak. When the coherence function is close to 0, it indicates that the linear correlation between the two signals at that frequency is very weak, and there are many components in the second vibration signal that cannot be explained linearly by the first vibration signal. This usually means that there are active local vibration sources or other nonlinear interferences.

[0100] The minimum value of the coherence function is taken as coh_min, and the adaptive adjustment factor is calculated based on the following formula:

[0101] α = 1 - coh_min.

[0102] The minimum value of the coherence function, coh_min, refers to the minimum point of the coherence function curve within a preset analysis frequency band, such as 0.5Hz to 50Hz in this embodiment, or a frequency band covering the main resonant frequency of the structure. This minimum value corresponds to the frequency component with the strongest local vibration source interference, resulting in the weakest linear correlation between the Y and Z signals. Those skilled in the art can also select the entire frequency band or other suitable frequency bands for minimum value search according to actual needs, all of which can achieve the purpose of this invention.

[0103] Choosing the minimum value of the coherence function, coh_min, as the basis for determining α has the physical meaning that the minimum value of the coherence function corresponds to the frequency component with the strongest local vibration source interference and the weakest linear correlation between the two signals. In other words, this minimum value reflects the degree of interference under the "worst-case" condition within the entire frequency band of interest. Based on this, setting α = 1 - coh_min achieves a monotonic mapping from the coherence surplus to the suppression requirement.

[0104] When the coherence is extremely good (coh_min ≈1), α≈0, the formula degenerates into a classical estimate, and almost no suppression is performed;

[0105] When the coherence is extremely poor (coh_min ≈0), α≈ 1, and the formula suppresses it to the greatest extent.

[0106] When the coherence is at the intermediate value, α changes continuously between 0 and 1, and the suppression strength increases or decreases synchronously with the interference strength.

[0107] Ultimately, by introducing coherence, the above scheme no longer relies on a simple signal amplitude ratio, but utilizes the statistical correlation between signals to achieve robust estimation of the structural transfer function in the frequency domain, and further obtains the real-time transfer relationship after suppressing interference. This real-time transfer relationship can effectively reflect the true stiffness and damping characteristics of the working platform structure under the current working conditions, thus ensuring the accuracy of the transfer relationship even in the presence of local vibration source interference.

[0108] Furthermore, in some embodiments, step S210, determining whether there is an active local vibration source on the work platform based on the first vibration signal and the second vibration signal, includes the following steps:

[0109] S211. At the known characteristic frequency of the local vibration equipment on the work platform, determine the coherence function value of the first vibration signal and the second vibration signal;

[0110] Locally vibrating equipment, such as hydraulic pumps, motors, and fans, typically possesses inherent operating frequencies or harmonic frequencies, known as "characteristic frequencies." Calculating the coherence function values ​​of a first and second vibration signal at these characteristic frequencies quantifies the degree of linear correlation between the two signals at that specific frequency. The coherence function values ​​are obtained using the aforementioned γ... 2 The calculation formula for (f) will not be repeated here.

[0111] S212. If the coherence function value is lower than a preset first threshold, it indicates that there is a vibration component in the second vibration signal that cannot be linearly explained by the first vibration signal, and it is determined that there is an active local vibration source interference.

[0112] When the coherence function value is low, it means that a significant portion of the vibration components in the second vibration signal are uncorrelated or have a very weak linear correlation with the first vibration signal. These components are likely to originate from local vibration sources within the work platform. The preset first threshold is a criterion for distinguishing the presence of significant local interference. It can be set based on historical data, experimental calibration, or expert experience, for example, to 0.5 or 0.6. In addition to a fixed threshold, a dynamic threshold can also be used, adaptively adjusted by the operator according to changes in environmental noise levels or operating conditions.

[0113] The above technical solution effectively identifies the presence of active local vibration sources interfering with the aerial work platform. When assessing the structural stability of the work platform, if a local vibration source exists, its vibrations will be superimposed on the vibration signal transmitted from the vehicle chassis to the work platform. This causes the second vibration signal to no longer simply reflect the transmission characteristics from the chassis to the platform, thus affecting the accuracy of the real-time transmission relationship. By using the coherence function value of the first and second vibration signals at known characteristic frequencies of the local vibration equipment to determine the presence of a local vibration source, it is possible to accurately distinguish between transmitted vibrations caused by external excitation and local vibrations generated within the platform. This avoids misjudging interference from local vibration sources as structural anomalies, significantly improving the accuracy of real-time transmission relationship calculations. Consequently, it enhances the reliability and accuracy of the aerial work platform structural stability assessment, reduces false alarms, and ensures operational safety and efficiency.

[0114] Furthermore, in some embodiments, step S400, the method for calculating the deviation between the real-time transfer relationship and the reference transfer relationship, includes:

[0115] S410. Within a preset neighborhood frequency band [fn(1-k), fn(1+k)] centered on the first-order natural frequency fn of the work platform structure, calculate the root mean square error of the amplitude spectrum of the real-time transfer relationship and the reference transfer relationship as the deviation; where k is a preset nominal proportionality coefficient, with a value range of 0.15≤k≤0.3; the neighborhood frequency band covers the resonance sensitive area of ​​the structural transfer characteristics so that the deviation mainly reflects the structural state change rather than the chassis excitation amplitude change.

[0116] Specifically, any elastic structural system (including the boom-platform system of an aerial work platform) possesses inherent vibration modes, among which the first natural frequency (i.e., the fundamental frequency) corresponds to the lowest-order bending or oscillating mode of the entire structure. This frequency is the most representative characteristic parameter in structural dynamics, and its value mainly depends on the structure's stiffness, mass, and damping distribution. When the structure experiences anomalies such as stiffness degradation, loose connections, or localized damage, the first natural frequency often undergoes observable changes (usually manifested as a frequency decrease). Simultaneously, the vibration response of the structure is most significant near the first natural frequency, and the amplitude spectrum of the transfer function exhibits a distinct resonance peak at this frequency. Therefore, the first natural frequency and its neighborhood represent the frequency band where information about structural state changes is most concentrated.

[0117] Based on the above principle, the calculation is performed within a preset neighborhood frequency band [fn(1-k), fn(1+k)] centered on the first-order natural frequency fn of the work platform structure. The first-order natural frequency fn can be determined by conducting modal tests on the work platform in a healthy state, such as impact tests or frequency sweep excitation tests, collecting vibration response data, and identifying the actual first-order natural frequency fn through frequency domain analysis (such as peak picking method, half-power bandwidth method, etc.).

[0118] The value of k, ranging from 0.15 to 0.3, is determined based on engineering experience: if the bandwidth is too narrow (k < 0.15), the deviation calculation may be unstable due to insufficient frequency resolution or slight resonant peak drift; if the bandwidth is too wide (k > 0.3), too many frequency components unrelated to the structural state will be introduced, reducing the sensitivity of the deviation to structural changes. Therefore, in this embodiment, a range of 0.15 to 0.3 is preferred.

[0119] After determining the aforementioned frequency band, this step calculates the root mean square error of the amplitude spectrum between the real-time transfer relation and the reference transfer relation within that frequency band, which serves as the quantized value of the deviation:

[0120]

[0121] i i i ) represents the amplitude of the reference transfer relationship at the corresponding frequency point, and N is the number of frequency points within the frequency band.

[0122] The root mean square error (RMSE) is used to measure the difference between two datasets. When applied to the comparison of amplitude spectra, it can quantify the degree of difference between the real-time transfer relation and the reference transfer relation within a specific frequency band, thus serving as a deviation index for assessing structural stability.

[0123] Through the above technical solution, this application focuses the calculation of deviation within a preset neighborhood frequency band centered on the first natural frequency fn of the work platform structure. This allows the deviation to primarily reflect the impact of structural state changes (such as stiffness degradation, loose connections, and damping changes) on transmission characteristics, while remaining insensitive to changes in chassis excitation amplitude. This effectively avoids interference from non-structural vibration noise in full-band analysis, significantly improving the sensitivity and accuracy of structural stability assessment. Consequently, it ensures the reliability of monitoring the structural state of the aerial work platform and provides solid technical support for timely detection of potential safety hazards.

[0124] Furthermore, in some embodiments, step S300, based on operating condition data and standard transfer relationships, obtains a reference transfer relationship reflecting the vibration transfer characteristics between the first monitoring point and the second monitoring point under the current operating conditions, which specifically includes:

[0125] S310. Obtain a calibration domain, which contains a set of standard transfer relationships measured by discrete calibration points corresponding to various working conditions when the work platform is in a healthy standard state.

[0126] This step aims to establish a comprehensive benchmark database to characterize the vibration transmission characteristics of the work platform under different health standard states and various operating conditions. The calibration domain can be a multi-dimensional parameter space, whose dimensions are composed of key operating condition parameters of the work platform (e.g., load weight, boom extension length, boom pitch angle, slewing angle, etc.). The health standard state refers to the state in which the work platform structure is in accordance with the design specifications, under normal, undamaged, or without significant performance degradation. The calibration points corresponding to the discrete operating condition data refer to a series of representative, pre-defined combinations of operating conditions selected within the multi-dimensional parameter space.

[0127] Specifically, the pre-calibration method for the standard transfer relationship set includes: when the working platform is in a healthy standard state and located within the calibration domain, selecting calibration points corresponding to various discrete working condition data, actively stimulating the chassis or applying measurable stimulation at each calibration point, synchronously collecting the first vibration signal and the second vibration signal, and calculating the standard transfer relationship under the corresponding working condition.

[0128] The aforementioned calibration points should cover multiple load weight levels from no load to rated load and attitude data at multiple angles from horizontal to maximum permissible tilt angle, as well as combinations of both, forming a two-dimensional grid-like distribution of calibration points.

[0129] At each calibration point, a known or measurable excitation needs to be applied to the chassis to induce the transmission of vibration from the chassis to the platform end. Excitation methods may include:

[0130] Active excitation: such as using a vibrator to apply sweep frequency excitation or pulse excitation to the chassis to obtain wideband transmission characteristics;

[0131] Operating excitation: such as making the vehicle engine run at a specific speed, using the engine's own vibration as an excitation source;

[0132] Impact excitation: such as using a hammer to strike the chassis, generating a wide-band impact response.

[0133] While applying the excitation, the first vibration signal Y(t) at the first monitoring point and the second vibration signal Z(t) at the second monitoring point are simultaneously acquired to ensure that the two signals are time-aligned.

[0134] Based on the synchronously acquired Y(t) and Z(t), the standard transfer function estimation method (such as the H1 estimator) or the anti-interference method of this invention (if there is local vibration source interference during the calibration process) is used to calculate the standard transfer relationship Hijstd(f) corresponding to the calibration point. The calculation results of all calibration points are associated and stored with the corresponding working condition data to form a set of standard transfer relationships.

[0135] S320. If the current operating condition data falls within the calibration domain, a reference transmission relationship reflecting the vibration transmission characteristics between the first monitoring point and the second monitoring point is obtained by interpolation between the calibration points.

[0136] This step aims to dynamically generate a health status reference baseline that matches the current operating condition based on real-time operating condition data. After the system acquires the current operating condition data (including load weight and attitude data), it determines whether the data falls within a predefined calibration domain. If the current operating condition data falls within the calibration domain but does not precisely match an existing calibration point, interpolation techniques are required. Interpolation refers to mathematically calculating the reference transfer relationship at the current non-calibrated operating condition point based on the standard transfer relationship at a known calibration point. Commonly used interpolation methods include, but are not limited to, linear interpolation, polynomial interpolation, spline interpolation (such as cubic spline interpolation), radial basis function interpolation, or Kriging interpolation. For example, if the current operating condition data lies between two or more adjacent calibration points, a weighted average or more complex function fitting can be performed on the standard transfer relationships of these adjacent calibration points to obtain the reference transfer relationship under the current operating condition. This ensures that an accurate reference baseline can be obtained even under operating conditions that have not been actually calibrated.

[0137] Secondly, this application proposes a stability evaluation system for the working platform of an aerial work vehicle, which includes an acquisition module configured to simultaneously acquire a first vibration signal at a first monitoring point on the vehicle chassis, a second vibration signal at a second monitoring point on the working platform, and working condition data of the working platform; wherein the working condition data includes the load weight of the working platform and the attitude data of the working platform.

[0138] The first calculation module is configured to obtain a real-time transmission relationship reflecting the vibration transmission characteristics between the first monitoring point and the second monitoring point based on the first vibration signal and the second vibration signal.

[0139] The second calculation module is configured to obtain a reference transmission relationship that reflects the vibration transmission characteristics between the first monitoring point and the second monitoring point under the current working conditions, based on the working condition data and the standard transmission relationship.

[0140] A stability assessment module is configured to calculate the deviation between the real-time transmission relationship and the reference transmission relationship; and to assess the structural stability of the operating platform based on the deviation.

[0141] The specific processes, principles, and beneficial effects of the methods and steps performed by the above modules have been introduced in the foregoing and will not be repeated here.

[0142] It should be noted that the sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0143] The terms "comprising" and "having," and any variations thereof, in the specification, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such process, method, product, or apparatus. The terms "first," "second," and "third," etc., are used to distinguish different objects, etc., and do not indicate a sequence, nor do they limit "first," "second," and "third" to different types.

[0144] In the description of the embodiments of this application, terms such as "exemplary," "for example," or "for instance" are used to indicate examples, illustrations, or explanations. Any embodiment or design described as "exemplary," "for example," or "for instance" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplary," "for example," or "for instance" is intended to present the relevant concepts in a concrete manner.

[0145] In the description of the embodiments of this application, unless otherwise stated, " / " means "or". For example, A / B can mean A or B. The "and / or" in the text is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, and B exists alone. In addition, in the description of the embodiments of this application, "multiple" means two or more.

[0146] In some processes described in the embodiments of this application, multiple operations or steps are included in a specific order. However, it should be understood that these operations or steps may not be executed in the order they appear in the embodiments of this application, or they may be executed in parallel. The sequence number of the operation is only used to distinguish different operations, and the sequence number itself does not represent any execution order. In addition, these processes may include more or fewer operations, and these operations or steps may be executed sequentially or in parallel, and these operations or steps may be combined.

[0147] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) as described above, and includes several instructions to cause a terminal device to execute the methods described in the various embodiments of this application.

[0148] The above are merely preferred embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A method for evaluating the stability of an aerial work platform, characterized in that, It includes the following steps: The system simultaneously acquires the first vibration signal from the first monitoring point on the vehicle chassis, the second vibration signal from the second monitoring point on the work platform, and the working condition data of the work platform; wherein, the working condition data includes the load weight of the work platform and the attitude data of the work platform. Based on the first vibration signal and the second vibration signal, a real-time transmission relationship reflecting the vibration transmission characteristics between the first monitoring point and the second monitoring point is obtained; Based on the aforementioned working condition data and standard transmission relationship, a reference transmission relationship reflecting the vibration transmission characteristics between the first monitoring point and the second monitoring point under the current working condition is obtained. Calculate the deviation between the real-time transfer relationship and the reference transfer relationship; The structural stability of the work platform is evaluated based on the deviation.

2. The method for evaluating the stability of the working platform of an aerial work vehicle as described in claim 1, characterized in that, The process of obtaining a real-time transmission relationship reflecting the vibration transmission characteristics between the first monitoring point and the second monitoring point based on the first vibration signal and the second vibration signal includes the following steps: Based on the first vibration signal and the second vibration signal, determine whether there is an active local vibration source on the work platform; If it does not exist, then based on the ratio of the first vibration signal and the second vibration signal, a real-time transmission relationship reflecting the transmission characteristics of the vibration signal is obtained; If present, the first vibration signal and the second vibration signal are combined and processed based on a preset local vibration source suppression analysis model to obtain a real-time transmission relationship reflecting the vibration transmission characteristics between the first monitoring point and the second monitoring point after suppressing the local vibration source interference.

3. The method for evaluating the stability of the working platform of an aerial work vehicle as described in claim 2, characterized in that, The local vibration source suppression analysis model obtains the real-time transmission relationship by combining the first vibration signal and the second vibration signal, including the following steps: Based on the first vibration signal and the second vibration signal, determine the first self-power spectral density of the first vibration signal, the second self-power spectral density of the second vibration signal, and the complex cross-power spectral density including the common energy intensity information and phase difference information of the first vibration signal and the second vibration signal; Based on the first self-power spectral density, the second self-power spectral density, the complex cross-power spectral density, and the coherence between the first vibration signal and the second vibration signal, the real-time transmission relationship after interference suppression is obtained.

4. The method for evaluating the stability of the working platform of an aerial work vehicle as described in claim 3, characterized in that, The real-time transmission relationship H_robust(f) after interference suppression is obtained based on the first self-power spectral density, the second self-power spectral density, the complex cross-power spectral density, and the coherence between the first vibration signal and the second vibration signal. The real-time transmission relationship H_robust(f) is obtained in the following way: H_robust(f) = G_yz(f) / (G_yy(f) - α * |G_yz(f)|) Wherein, G_yy(f) is the first self-power spectral density; G_yz(f) is the complex cross-power spectral density; α is an adaptive adjustment factor obtained based on the coherence between the first vibration signal and the second vibration signal, and 0 ≤ α < 1.

5. The method for evaluating the stability of the working platform of an aerial work vehicle as described in claim 4, characterized in that, The adaptive adjustment factor α is determined through the following steps: Calculate the coherence function γ²(f) between the first vibration signal and the second vibration signal: γ²(f) = |G_yz(f)| 2 / (G_yy(f) * G_zz(f)); where G_yy(f) is the first auto-power spectral density; G_yz(f) is the complex cross-power spectral density; and G_zz(f) is the second auto-power spectral density. Take the minimum value of the coherence function, coh_min, and calculate the adaptive adjustment factor based on the following formula: α = 1 - coh_min.

6. The method for evaluating the stability of the working platform of an aerial work vehicle as described in claim 2, characterized in that, The step of determining whether there is an active local vibration source on the work platform based on the first vibration signal and the second vibration signal includes the following steps: At a known characteristic frequency of the local vibration equipment on the work platform, determine the coherence function value of the first vibration signal and the second vibration signal; If the coherence function value is lower than a preset first threshold, it is determined that there is an active local vibration source interference.

7. The method for evaluating the stability of the working platform of an aerial work vehicle as described in claim 1, characterized in that, The calculation of the deviation between the real-time transfer relationship and the reference transfer relationship includes: Within a preset neighborhood frequency band [fn(1-k), fn(1+k)] centered on the first-order natural frequency fn of the work platform structure, the root mean square error of the amplitude spectrum between the real-time transfer relationship and the reference transfer relationship is calculated as the deviation. Wherein, k is a preset nominal proportional coefficient, with a value range of 0.15≤k≤0.3; the neighborhood frequency band covers the resonant sensitive area of ​​the structural transmission characteristics, so that the deviation mainly reflects the change in structural state rather than the change in chassis excitation amplitude.

8. The method for evaluating the stability of the working platform of an aerial work vehicle as described in claim 1, characterized in that, The reference transmission relationship, which reflects the vibration transmission characteristics between the first monitoring point and the second monitoring point under the current operating conditions, is obtained based on the operating condition data and the standard transmission relationship. This includes: Obtain a calibration domain, which contains a set of standard transfer relationships measured by discrete calibration points corresponding to various working conditions when the work platform is in a healthy standard state. If the current operating condition data falls within the calibration domain, a reference transmission relationship reflecting the vibration transmission characteristics between the first monitoring point and the second monitoring point can be obtained through interpolation between the calibration points.

9. The method for evaluating the stability of the working platform of an aerial work vehicle as described in claim 8, characterized in that, The standard transitive relation set is predefined in the following manner: When the operating platform is in a healthy standard state and within the calibration domain, the calibration points corresponding to various discrete working condition data are selected, and the chassis is actively excited or a measurable excitation is applied at each calibration point. The first vibration signal and the second vibration signal are collected simultaneously, and the standard transmission relationship under the corresponding working condition is calculated.

10. A stability evaluation system for the working platform of an aerial work vehicle, characterized in that, It includes: The acquisition module is configured to simultaneously acquire a first vibration signal from a first monitoring point on the vehicle chassis, a second vibration signal from a second monitoring point on the work platform, and working condition data of the work platform; wherein the working condition data includes the load weight of the work platform and the attitude data of the work platform. The first calculation module is configured to obtain a real-time transmission relationship reflecting the vibration transmission characteristics between the first monitoring point and the second monitoring point based on the first vibration signal and the second vibration signal. The second calculation module is configured to obtain a reference transmission relationship that reflects the vibration transmission characteristics between the first monitoring point and the second monitoring point under the current working conditions, based on the working condition data and the standard transmission relationship. A stability assessment module is configured to calculate the deviation between the real-time transmission relationship and the reference transmission relationship; and to assess the structural stability of the operating platform based on the deviation.

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