A method, system, device, and medium for cable vibration measurement

Abstract

The application discloses a kind of cable vibration measurement method, system, equipment and medium, wherein method includes: the xyz axis of acceleration sensor is used to collect the vibration acceleration data of cable and is filtered;According to the vibration acceleration data of xyz axis, the resultant acceleration is obtained, and the gravity acceleration component and cable vibration acceleration component are separated from the resultant acceleration data;According to the gravity acceleration component, the Euler angle in the rotation process of acceleration sensor is solved, and the Euler angle obtained by solving is verified;According to the Euler angle, the rotation matrix of cable vibration acceleration is constructed to convert the acceleration sensor coordinate system to cable coordinate system;Based on the rotation matrix, vibration acceleration data and cable vibration acceleration component, the vibration acceleration of cable in xyz axis is solved.The application solves the problem that the prior art cannot accurately measure cable vibration when cable position angle changes.

Description

Technical Field

[0001] This invention relates to the field of cable condition monitoring technology, and in particular to a cable vibration measurement method, system, device and medium. Background Technology

[0002] High-voltage cables are a critical component of power transmission systems, and their operational status directly affects the stability and security of the power grid. However, in actual operation, high-voltage cables are often affected by external environmental factors (such as wind, mechanical shock, and electromagnetic forces) and internal factors (such as current variations and temperature fluctuations), causing cable vibration. This vibration not only accelerates the aging of cable materials but can also lead to serious problems such as loose cable joints, insulation wear, and even breakage, thereby threatening the safe operation of the power system.

[0003] In existing technologies, sensors are typically fixed to the cable surface to directly measure vibration acceleration. However, during actual operation, cables undergo positional changes such as bending and torsion due to factors like temperature, load, and wind force. This causes the sensor's measurement direction to differ from the cable's actual vibration direction, resulting in measurement errors. Because of the variable cable position, vibration measurement data is difficult to unify into the cable's own coordinate system. Existing methods often ignore the influence of cable positional changes, leading to measurement data that cannot accurately reflect the cable's true vibration state, making effective comparison and analysis difficult. Furthermore, vibration measurement relies solely on data from the accelerometer, neglecting the impact of cable positional angle changes on the measurement results, resulting in low measurement accuracy, especially in cases of dynamic cable positional changes.

[0004] Therefore, how to correct vibration data to the cable's own coordinate system under highly dynamic cable positional changes in order to achieve unified and accurate vibration measurement and evaluation has become a pressing problem in the current technical field. Summary of the Invention

[0005] This invention provides a cable vibration measurement method, system, device, and medium to solve the problem that existing technologies cannot accurately measure cable vibration when the cable's position angle changes.

[0006] In view of this, the first aspect of the present invention provides a method for measuring cable vibration, the method comprising:

[0007] Vibration acceleration data of the cable under test is acquired using the x-axis, y-axis and z-axis of an accelerometer, and the vibration acceleration data is then filtered.

[0008] The composite acceleration is plotted based on the vibration acceleration data of the x-axis, y-axis and z-axis, and the gravitational acceleration component and the cable vibration acceleration component are separated from the composite acceleration data.

[0009] The Euler angles during the rotation of the accelerometer are calculated based on the gravitational acceleration components, and the calculated Euler angles are verified to obtain the verified Euler angles.

[0010] A rotation matrix for cable vibration acceleration is constructed based on the Euler angles to transform the accelerometer coordinate system to the cable coordinate system;

[0011] Based on the rotation matrix, the vibration acceleration data, and the cable vibration acceleration components, the vibration acceleration of the cable along the x-axis, y-axis, and z-axis is calculated.

[0012] Optionally, the acquisition of vibration acceleration data of the cable under test using the x-axis, y-axis, and z-axis of an accelerometer includes:

[0013] The vibration acceleration data of the cable under test is collected using the x-axis, y-axis and z-axis of an accelerometer and based on a preset sampling frequency.

[0014] Optionally, filtering the vibration acceleration data includes:

[0015] The vibration acceleration data were filtered using a Kalman filter.

[0016] Optionally, separating the gravitational acceleration component and the cable vibration acceleration component from the synthesized acceleration data includes:

[0017] Several initial gravitational acceleration components are obtained by calculating the median value of the vibration amplitude over several vibration cycles. The average value of the median values ​​of each vibration amplitude is calculated and used as the final gravitational acceleration component. The cable vibration acceleration component is obtained by subtracting the gravitational acceleration component from the composite acceleration.

[0018] Optionally, calculating the Euler angles during the rotation of the accelerometer based on the gravitational acceleration component includes:

[0019] A set of nonlinear equations is constructed based on the gravitational acceleration components, and the Euler angles during the rotation of the accelerometer are obtained by solving the set of nonlinear equations.

[0020] The nonlinear equation set is as follows:

[0021] ;

[0022] In the formula, g x g y g z These represent the gravitational acceleration values ​​in the three directions, and α, β, and γ represent the deflection angles in the x, y, and z directions, respectively.

[0023] Optionally, constructing the rotation matrix of cable vibration acceleration based on the Euler angles includes:

[0024] Based on the Euler angles, construct coordinate transformation matrices for rotation around the x-axis, the y-axis, and the z-axis, respectively. Determine the total rotation matrix based on the coordinate transformation matrices for rotation around the y-axis and the z-axis, and use this matrix as the rotation matrix.

[0025] Optionally, the step of calculating the vibration acceleration of the cable in each direction based on the rotation matrix, the vibration acceleration data, and the cable vibration acceleration components includes:

[0026] Based on the rotation matrix, the vibration acceleration data, and the matrix relationship of the cable vibration acceleration components, the cable vibration acceleration matrix is ​​obtained by solving the rotation matrix and the vibration acceleration data, thereby obtaining the cable vibration acceleration on the x-axis, y-axis, and z-axis at a certain sampling time.

[0027] A second aspect of the present invention provides a cable vibration measurement system, the system comprising:

[0028] The acquisition unit is used to acquire vibration acceleration data of the cable under test using the x-axis, y-axis and z-axis of the accelerometer, and to filter the vibration acceleration data.

[0029] The separation unit is used to plot the composite acceleration based on the vibration acceleration data of the x-axis, y-axis and z-axis, and to separate the gravitational acceleration component and the cable vibration acceleration component from the composite acceleration data;

[0030] The first calculation unit is used to calculate the Euler angles during the rotation of the accelerometer based on the gravitational acceleration component, and to verify the calculated Euler angles to obtain the verified Euler angles.

[0031] A construction unit is used to construct a rotation matrix for the cable vibration acceleration based on the Euler angles, so as to transform the accelerometer coordinate system to the cable coordinate system;

[0032] The second calculation unit is used to calculate the vibration acceleration of the cable along the x-axis, y-axis, and z-axis based on the rotation matrix, the vibration acceleration data, and the cable vibration acceleration components.

[0033] A third aspect of the present invention provides a cable vibration measuring device, the device comprising a processor and a memory:

[0034] The memory is used to store program code and transmit the program code to the processor;

[0035] The processor is configured to execute the steps of the cable vibration measurement method as described in the first aspect above, according to the instructions in the program code.

[0036] A fourth aspect of the present invention provides a computer-readable storage medium for storing program code for executing the cable vibration measurement method described in the first aspect above.

[0037] As can be seen from the above technical solutions, the present invention has the following advantages:

[0038] This invention provides a cable vibration measurement method. First, an accelerometer is used to collect vibration acceleration data of the cable under test, and the data is filtered to reduce noise interference. Next, the cable acceleration is decomposed using the trigonometric relationship between the accelerometer and the cable surface to obtain the numerical relationship between the cable acceleration and the accelerometer data, thereby calculating the cable's own acceleration based on the measured data. Then, using the gravitational acceleration components of each axis of the accelerometer, the Euler angles of the accelerometer's rotation around its own xyz axes, with the cable surface as the coordinate reference, can be calculated. Finally, the rotation matrix of the accelerometer can be calculated based on the Euler angles. This rotation matrix reflects the conversion relationship between the cable vibration acceleration data and the acceleration data measured by the accelerometer, thus obtaining the cable vibration acceleration. This solves the problem in existing technologies where accurate measurement of cable vibration is impossible when the cable's position angle changes.

[0039] Compared with existing technologies:

[0040] 1. Lower cost compared to long-term online monitoring equipment;

[0041] 2. It has strong adaptability to the working environment, strong load-bearing capacity at normal temperature, and can work stably for a long time in harsh environments;

[0042] 3. Low requirements for computer equipment performance; convenient and fast data processing methods.

[0043] 4. It can be combined with long-term online equipment and the data processing method of this invention can be embedded to achieve long-term online and accurate monitoring. Attached Figure Description

[0044] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0045] Figure 1 This is a schematic flowchart of a cable vibration measurement method provided in an embodiment of the present invention;

[0046] Figure 2 This is a schematic diagram of a cable vibration measurement system provided in an embodiment of the present invention. Detailed Implementation

[0047] To make the objectives, features, and advantages of this invention more apparent and understandable, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described below are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0048] Explanation of relevant terms:

[0049] Accelerometer: A device used to measure the acceleration of an object, typically with triaxial measurement capabilities; this accelerometer can simultaneously acquire acceleration data of an object in three orthogonal directions: X, Y, and Z. In the scenario of cable vibration measurement, these three directions correspond to the axial vibration, horizontal radial vibration, and vertical radial vibration of the cable, respectively, thereby comprehensively capturing the vibration state of the cable in different dimensions.

[0050] Kalman filtering: a recursive filter for estimating unknown states, capable of handling measurement noise. The recursive nature of this Kalman filter means that each step only needs to update using the state estimate from the previous moment and the measurement data from the current moment, eliminating the need to store large amounts of historical data and significantly reducing the demand for computer storage resources. Simultaneously, its algorithm has low computational complexity and can achieve real-time data processing even on low-configuration embedded devices or ordinary office computers, fully meeting the design requirements of this invention for low device performance and convenient and fast data processing. In cable vibration measurement scenarios, this Kalman filter can perform real-time noise reduction and state estimation on triaxial vibration data collected by accelerometers, effectively filtering out measurement noise caused by environmental interference and accurately extracting the true vibration state information of the cable.

[0051] Gravitational acceleration component: The acceleration component caused by gravity, which is usually a constant.

[0052] Euler angles: Angles used to describe the orientation of an object in three-dimensional space.

[0053] Rotation matrix: A matrix that represents the relationship between coordinate systems and reflects rotation operations.

[0054] The principle of the cable vibration measurement method of this invention is described in detail below:

[0055] Because the accelerometer is not perfectly flush with the cable surface, the acceleration data measured by the accelerometer does not directly reflect the cable's own acceleration. Therefore, the accelerometer's position needs to be corrected. Thus, the cable acceleration can be decomposed using the trigonometric relationship between the accelerometer and the cable surface, obtaining the numerical relationship between the cable acceleration and the accelerometer data. Based on the measured data, the cable's own acceleration can then be calculated.

[0056] The accelerations along the x, y, and z axes of the accelerometer are the superposition of gravitational acceleration and cable vibration acceleration on their respective axes. Since the installation position is fixed, the gravitational acceleration component is constant, while the cable vibration acceleration component is a periodically varying quantity. Therefore, by averaging the composite acceleration data of each axis, the gravitational acceleration component can be separated, and the cable vibration acceleration component can be obtained using the superposition theorem. Using the gravitational acceleration components of each axis of the accelerometer, the Euler angles (ignoring translation) of the accelerometer's rotation around its own x, y, and z axes in a coordinate reference system with the cable surface as the reference can be calculated. Based on the Euler angles, the rotation matrix of the accelerometer can be calculated. This rotation matrix reflects the conversion relationship between the cable vibration acceleration data and the acceleration data measured by the accelerometer, thus allowing the cable vibration acceleration to be obtained.

[0057] In other words, when using an accelerometer to measure cable vibration, the sensor's attitude deflects as the cable's position changes, causing the measurement data to be mixed with changes in the gravitational component due to the sensor's own tilt, thus failing to directly reflect the cable's true vibration. To address this, this method starts with the sensor's triaxial composite acceleration data. Utilizing the characteristics that the gravitational acceleration component is a constant value while the cable vibration component is a periodic fluctuation, the average of the acceleration data over a period of time is calculated to separate the gravitational acceleration components along each axis, thereby extracting the cable vibration acceleration components. Based on this, the spatial deflection angle (Eulerian angle) of the sensor relative to the cable surface is calculated from the separated gravitational components, and a coordinate rotation matrix is ​​established accordingly. This transforms the acceleration data measured in the sensor's coordinate system to the cable's own coordinate system, eliminating the influence of attitude deviation and ultimately obtaining the cable's true vibration acceleration in each direction, achieving accurate measurement of the cable's vibration state.

[0058] The specific steps of the cable vibration measurement method of the present invention are described below:

[0059] Please see Figure 1 The cable vibration measurement method provided in this embodiment of the invention includes:

[0060] Step 101: Collect vibration acceleration data of the cable to be measured using the x-axis, y-axis and z-axis of the accelerometer, and filter the vibration acceleration data.

[0061] Understandably, an accelerometer is first used to collect cable vibration acceleration data. Then, the vibration data collected by the accelerometer along its x, y, and z axes are filtered to reduce noise interference. The x, y, and z axes of the accelerometer refer to three predefined orthogonal coordinate axes when the accelerometer is mounted on the cable surface: the x-axis is parallel to the axial extension direction of the cable, the y-axis is perpendicular to the cable surface and points outwards away from the cable, and the z-axis, together with the x and y axes, forms a right-handed Cartesian coordinate system. Its direction is determined by the right-hand screw rule, and it is used to characterize the sensor's attitude and orientation in space, providing the basic coordinate basis for subsequent Euler angle calculations and vibration acceleration data conversion.

[0062] Step 102: Calculate the composite acceleration based on the vibration acceleration data of the x-axis, y-axis and z-axis, and separate the gravitational acceleration component and the cable vibration acceleration component from the composite acceleration data.

[0063] Understandably, this step involves separating the gravitational acceleration component and the cable vibration acceleration component, including: first, plotting the composite acceleration based on the vibration acceleration data of the x-axis, y-axis, and z-axis; analyzing the data of each axis of the accelerometer to obtain the gravitational acceleration component; and subtracting the gravitational acceleration component from the measured composite acceleration to extract the cable vibration acceleration component.

[0064] Step 103: Calculate the Euler angles during the rotation of the accelerometer based on the gravitational acceleration components, and verify the calculated Euler angles to obtain the verified Euler angles.

[0065] Understandably, this step involves calculating the Euler angles (α, β, γ) of the accelerometer using the gravitational acceleration components and verifying their validity. The calculation of the accelerometer's Euler angles is based on the relative relationship between the gravitational acceleration components and the sensor's measurement coordinate system. Through a series of complex mathematical calculations, the accelerometer's attitude angles in three-dimensional space can be accurately obtained. The verification process ensures the accuracy of the calculation by comparing the results with expected physical laws or known conditions. This step is crucial for subsequent analysis of cable vibration characteristics because only by accurately knowing the accelerometer's attitude can the measured acceleration be accurately converted into the actual vibration of the cable.

[0066] Step 104: Construct a rotation matrix for the cable vibration acceleration based on Euler angles to transform the accelerometer coordinate system to the cable coordinate system.

[0067] Understandably, this step utilizes the established rotation matrix and vibration acceleration data to calculate the cable's vibration acceleration in various directions, achieving precise coordinate system transformation. In other words, the rotation matrix is ​​constructed based on verified Euler angles, and the calculation process involves only basic matrix multiplication, requiring no complex iterative algorithms or high-order numerical processing steps. Ordinary embedded devices or low-configuration computers can complete this task quickly. Furthermore, the logic of the coordinate system transformation is clear and intuitive, and the data processing flow is concise and compact, avoiding redundant calculations. This ensures the accuracy of the transformation results while significantly reducing the performance requirements of the equipment, making the coordinate transformation of cable vibration acceleration highly efficient.

[0068] Step 105: Based on the rotation matrix, vibration acceleration data, and cable vibration acceleration components, calculate the cable's vibration acceleration along the x, y, and z axes.

[0069] Understandably, this step utilizes the established rotation matrix and vibration acceleration data to calculate the cable's vibration acceleration in various directions, achieving precise coordinate system transformation. In other words, the key calculations in this step involve only matrix and vector multiplication, without requiring complex mathematical libraries or extensive iterative calculations. Even embedded devices with limited computing power or older computers can complete the calculation of a single set of data within milliseconds. Furthermore, the data processing flow avoids redundant intermediate steps; each operation directly serves the goal of coordinate system transformation, ensuring the accuracy of the calculation results while minimizing hardware resource consumption, making the entire cable vibration acceleration calculation process efficient and easy to deploy.

[0070] In summary, the cable vibration measurement method provided by this invention first uses an accelerometer to collect vibration acceleration data of the cable under test, and then filters the vibration acceleration data to reduce noise interference. Next, using the trigonometric relationship between the accelerometer and the cable surface, the cable acceleration is decomposed to obtain the numerical relationship between the cable acceleration and the accelerometer data, thereby calculating the cable's own acceleration based on the measured data. Then, using the gravitational acceleration components of each axis of the accelerometer, the Euler angles of the accelerometer's rotation around its own xyz axes in a coordinate reference system with the cable surface as the reference can be calculated. Finally, based on the Euler angles, the rotation matrix of the accelerometer can be calculated. The rotation matrix reflects the conversion relationship between the cable vibration acceleration data and the acceleration data measured by the accelerometer, thus obtaining the cable vibration acceleration. This solves the problem in existing technologies where accurate measurement of cable vibration is impossible when the cable's position angle changes.

[0071] In one embodiment, step 101 includes:

[0072] First, the vibration acceleration data of the cable under test is collected using the x, y, and z axes of an accelerometer based on a preset sampling frequency; then, the vibration acceleration data is filtered using a Kalman filter.

[0073] It should be noted that, according to relevant research, cable vibration is caused by the action of power frequency electromagnetic field, and the vibration intensity is concentrated at integer multiples of 100Hz and 50Hz. Therefore, the preset sampling frequency of this invention is ≥1000Hz. Those skilled in the art can set other sampling frequencies according to actual conditions, which are not limited here.

[0074] It should be noted that the filtering method used in this invention is Kalman filtering because Kalman filtering has the characteristics of optimal estimation and strong noise processing capabilities, which can effectively reduce the interference of noise signals.

[0075] In this embodiment, firstly, during the data acquisition stage, considering that cable vibration is mainly excited by power frequency electromagnetic fields and that vibration energy is concentrated in the 100Hz and 50Hz integer multiples of the frequency band, the preset sampling frequency is set to no less than 1000Hz according to the sampling theorem. This ensures that the high-frequency components of the vibration signal can be completely captured, avoiding signal aliasing or feature loss due to insufficient sampling frequency. Secondly, in the filtering stage, the Kalman filter algorithm, which has optimal estimation capabilities and strong noise suppression performance, is selected to process the raw acceleration data. This effectively reduces the interference of environmental noise and measurement random errors, improves the signal-to-noise ratio while preserving the true vibration characteristics, and provides a cleaner and more reliable data foundation for subsequent steps such as gravity component separation, Euler angle calculation, and coordinate transformation.

[0076] In one embodiment, step 102, separating the gravitational acceleration component and the cable vibration acceleration component from the synthesized acceleration data, includes:

[0077] Several initial gravitational acceleration components are obtained by calculating the median value of the vibration amplitude over several vibration cycles. The average value of the median value of each vibration amplitude is calculated and used as the final gravitational acceleration component. The cable vibration acceleration component is obtained by subtracting the gravitational acceleration component from the synthesized acceleration.

[0078] It should be noted that all coordinate systems are set to right-handed during the calculation process. Since some accelerometer measurements are in left-handed coordinate system, they need to be converted to right-handed coordinate system. Therefore, it is only necessary to invert the z-axis data.

[0079] The specific implementation method is as follows:

[0080] Three coordinate systems are defined: the measurement coordinate system, which is the x, y, and z axis coordinate system collected by the corresponding measuring equipment; the gravity coordinate system, which is a right-handed coordinate system with the direction of gravitational acceleration as the positive z-axis; and the cable coordinate system, which is a right-handed coordinate system with the cable axis as the y-direction and the normal of the y-direction and the plane containing gravitational acceleration as the x-direction.

[0081] The total acceleration measured by the accelerometer is used to plot the composite acceleration. Clearly, because the measurement coordinate system, cable coordinate system, and gravity coordinate system are not coincident, the composite acceleration varies periodically around the component of gravitational acceleration on the z-axis of the gravity coordinate system, not around zero. By finding the maximum and minimum values ​​within a period, the median of the vibration amplitude within that period can be obtained, i.e., the gravitational acceleration component. By finding the median values ​​of multiple periods and averaging them to reduce errors, the components of gravitational acceleration on each axis can be calculated.

[0082] Subtracting the gravitational acceleration component from the composite acceleration yields the cable vibration acceleration components along the x, y, and z axes of the accelerometer. The curve shows that the cable vibration acceleration components periodically change around zero. This is understandable because, firstly, due to the accelerometer's deflection with the cable's attitude, the original composite acceleration signal contains both a constant gravitational acceleration component and a periodically fluctuating cable vibration component. Therefore, the waveform appears as a curve undulating around a non-zero bias value; the vibration is not symmetrical about zero. Secondly, by calculating the average of the median amplitudes over multiple vibration cycles and subtracting this constant gravitational bias from the composite signal, the resulting cable vibration acceleration component waveform exhibits a periodic variation around zero. This is because removing the gravitational "background" reveals the actual acceleration response of the cable reciprocating around its equilibrium position, symmetrical in both positive and negative directions, with a mean approaching zero. Finally, this phenomenon not only intuitively verifies the correctness of the gravity separation step, i.e., if the separation is incomplete, the waveform center will deviate from zero, but also provides a clean vibration data basis for subsequent inverse calculation of Euler angles based on gravity components, ensuring the accuracy of attitude calculation and coordinate transformation.

[0083] In this embodiment, it can be understood that because the sensor and cable coordinate systems do not coincide, the synthesized acceleration manifests as a periodic signal fluctuating around a certain non-zero bias (i.e., the gravity component). By obtaining the median of the maximum and minimum values ​​within a single vibration cycle, a preliminary estimate of the gravitational acceleration component within that cycle can be obtained. Then, the medians obtained from multiple cycles are averaged to obtain a more stable and accurate gravity component value. The purpose of this operation is to separate the constant gravity bias, which does not change with vibration, from the original signal, and then extract the pure cable vibration acceleration component that periodically changes around zero by subtracting this gravity component from the synthesized acceleration. This process also clarifies the definitions of the measurement, gravity, and cable coordinate systems, and points out that when the sensor uses a left-handed coordinate system, the z-axis needs to be reversed to unify it to a right-handed coordinate system, thus providing correct input data for subsequent calculation of Euler angles and coordinate transformation based on the gravity component.

[0084] In one embodiment, step 103, calculating the Euler angles during the rotation of the accelerometer based on the gravitational acceleration components, includes:

[0085] A set of nonlinear equations is constructed based on the gravitational acceleration components, and the Euler angles during the rotation of the accelerometer are obtained by solving the set of nonlinear equations.

[0086] It should be noted that the positional relationship between the accelerometer and the cable surface can be viewed as the accelerometer rotating around its own xyz axes with the cable coordinate system as the reference coordinate system. This results in an angular relationship between the accelerometer's coordinate system and the cable coordinate system. Specifically, the direction of the cable's vibration acceleration is not equal to the direction of the acceleration measured by the accelerometer, requiring correction. Correction requires the Euler angles during the accelerometer's rotation, i.e., the angle of offset of the accelerometer relative to the cable.

[0087] For the zy plane:

[0088] ;

[0089] For the xz plane:

[0090] ;

[0091] For the xy plane:

[0092] ;

[0093] From the above, we can conclude that:

[0094] ;

[0095] In the formula, g x g y g zThese represent the gravitational acceleration values ​​in the three directions, and α, β, and γ represent the deflection angles in the x, y, and z directions, respectively.

[0096] Obviously, α (yaw angle), β (pitch angle), and γ (roll angle) can be obtained by solving the nonlinear equation system. This can be done using the built-in function fsolve in MATLAB (a commercial mathematical software produced by MathWorks, a high-level technical computing language and interactive environment used for algorithm development, data visualization, data analysis, and numerical computation, mainly consisting of MATLAB and Simulink). However, the angles obtained are not unique and need to be verified to ensure their reasonableness.

[0097] Since the sensor is mounted above the cable surface, the rotation range for each angle is defined as follows: α = [-180°, 180°], β = [-90°, +90°], and γ = [-90°, +90°]. Simultaneously, since γ can be approximately 0, cos(γ) ≈ 1, sin(γ) ≈ 0. Therefore, arf = asin(-g y / g), beta=atan(-g) x / g z If human error exists during installation, preventing γ from being approximated as 0, the deflection angle can be measured using tools such as a protractor for calculation. It is understandable that when the accelerometer is mounted above the cable surface, its roll angle γ around its z-axis mainly reflects the tangential contact deviation between the sensor's bottom surface and the cable surface. Under ideal installation conditions, with the sensor's bottom surface parallel to the cable surface, γ should be close to zero. Therefore, the approximate conditions of cos(γ)≈1 and sin(γ)≈0 can be used to simplify the originally coupled nonlinear equations into analytical expressions α≈arcsin(-gy / g) and β≈arctan(-gx / gz), thereby quickly obtaining estimates of the yaw and pitch angles and reducing the complexity of numerical solutions. Meanwhile, the rotation ranges of α, β, and γ are restricted. α is [-180°, 180°], reflecting the full circumference possible in the yaw direction. β and γ are restricted to [-90°, 90°] because pitch and roll are constrained by installation geometry, preventing inversion or flipping. This range constraint eliminates inconsistencies among multiple solutions while conforming to engineering realities. If γ becomes non-negligible due to human installation errors, this fixed yaw angle can be pre-measured using tools such as a protractor and substituted into the equations as a known parameter, thus allowing the simplified solution approach to continue while ensuring calculation accuracy.

[0098] This embodiment utilizes the gravitational acceleration components separated in the previous step to inversely determine the attitude deviation angles (i.e., Euler angles α, β, γ) of the accelerometer relative to the cable coordinate system. The key is to construct a nonlinear equation system based on the distribution relationship of the gravitational components along the three axes of the sensor, and to obtain the yaw, pitch, and roll angles through numerical solutions. Since the direction of gravity remains constant in space, once the sensor tilts, the projection values ​​of gravity on each axis will change accordingly. Therefore, inversely determining the angles based on gx, gy, and gz is physically reversible. This step accurately obtains the deflection angles of the sensor caused by installation or cable positional changes, thus providing crucial positional parameters for subsequently establishing the rotation matrix and correcting the measurement data from the sensor coordinate system to the cable's own coordinate system. Furthermore, this embodiment addresses the potential for multiple solutions by constraining the angle range based on the actual installation conditions and simplifying the estimation using the condition that the roll angle is approximately zero, thereby improving the solution efficiency and the reliability of the results.

[0099] In one embodiment, step 104 includes:

[0100] Construct coordinate transformation matrices for rotation around the x-axis, y-axis, and z-axis using Euler angles. Determine the overall rotation matrix based on the coordinate transformation matrices for rotation around the y-axis and z-axis, which will serve as the rotation matrix.

[0101] It should be noted that the rotation process of the accelerometer can be represented by a rotation matrix. The specific derivation process is as follows.

[0102] It is important to note that the order of rotation during the rotation process determines the calculation of Euler angles. The rotation order must be strictly defined, such as the X, Y, and Z axes in this case.

[0103] The positive direction is counterclockwise rotation around the x-axis, and the rotation angle is α:

[0104] ;

[0105] Similarly, rotating about the y-axis:

[0106] ;

[0107] Similarly, rotating about the z-axis:

[0108] ;

[0109] Therefore, the coordinate transformation matrix for rotation around the x-axis is:

[0110] ;

[0111] The coordinate transformation matrix for rotation about the y-axis is:

[0112] ;

[0113] The coordinate transformation matrix for rotation about the z-axis is:

[0114] ;

[0115] This embodiment, based on the Euler angles (α, β, γ) obtained in the previous step, constructs coordinate transformation matrices around each coordinate axis according to a predefined rotation order (first around the x-axis, then around the y-axis, and finally around the z-axis), and obtains the total rotation matrix through matrix multiplication. The purpose of this step is to quantitatively express the attitude deviation of the accelerometer's own coordinate system relative to the cable's coordinate system using mathematical matrix form, thus providing a coordinate transformation tool for accurately converting the acceleration data measured by the sensor to the cable's own coordinate system in subsequent steps. Since the construction of the rotation matrix depends on the rotation order of the Euler angles, this embodiment particularly emphasizes the requirement for a specific order to avoid deviations in the transformation results due to different orders, ensuring the consistency and accuracy of the final calculated cable vibration acceleration.

[0116] In one embodiment, step 105 includes:

[0117] Based on the matrix relationship between the rotation matrix, vibration acceleration data, and cable vibration acceleration components, the cable vibration acceleration matrix is ​​obtained by solving the rotation matrix and vibration acceleration data, thereby obtaining the cable vibration acceleration on the x-axis, y-axis, and z-axis at a certain sampling time.

[0118] It should be noted that the rotation matrices [X], [Y], and [Z] obtained from steps 103 and 104 can yield the total rotation matrix [T] = [Z] × [Y] of the cable vibration acceleration. The vibration acceleration data obtained from step 101 (i.e., the vibration acceleration matrix [A]) and the cable vibration acceleration components obtained from step 102 (i.e., the cable's own vibration acceleration matrix [B]) satisfy the matrix relationship: [A] = [T] × [B]. Therefore, matrix [B] can be calculated to obtain the triaxial vibration acceleration of the cable at a certain sampling time.

[0119] ;

[0120] ;

[0121] Through the above steps, the cable's own vibration acceleration can be calculated. Integrating the vibration acceleration yields the acceleration signal; double integration of the acceleration signal yields the displacement signal. It can be understood that acceleration is the derivative of velocity with respect to time, and velocity is the derivative of displacement with respect to time; conversely, a single time integration of acceleration yields velocity, and a double integration yields displacement. After obtaining the true vibration acceleration in the cable's own coordinate system through the aforementioned steps, numerical integration methods (such as trapezoidal integration or Simpson integration) can be used to process the acceleration time series. First, the vibration velocity signal is obtained, reflecting the instantaneous speed of cable vibration; then, the velocity signal is further integrated to obtain the vibration displacement signal, reflecting the actual amplitude of the cable's deviation from its equilibrium position during vibration. It should be noted that in practical engineering applications, accelerometers exhibit zero-point drift and low-frequency noise. Direct integration can lead to the accumulation of trend terms, causing severe drift in the displacement result. Therefore, before integration, the acceleration signal usually needs to be detrended or high-pass filtered to eliminate the DC component. Once an accurate displacement signal is obtained, it can be used to assess whether cable vibration exceeds the allowable amplitude range and to determine whether there is a risk of loose joints or fatigue damage.

[0122] This embodiment utilizes the matrix relationship between the established total rotation matrix and the sensor's measured acceleration matrix to obtain the true vibration acceleration matrix in the cable's own coordinate system through matrix inverse operations. This allows for the acquisition of the cable's vibration acceleration in the x, y, and z directions at any given sampling moment. This step thoroughly corrects the measurement data, which was previously influenced by sensor attitude, to the cable's own coordinate system, completing the mathematical transformation from raw data to actual vibration. Furthermore, integrating the corrected vibration acceleration yields the vibration velocity signal, and double integration provides the vibration displacement signal, thus enabling a comprehensive assessment of the cable's vibration state.

[0123] In summary, the cable vibration measurement method provided by this invention first uses an accelerometer to collect vibration acceleration data of the cable under test, and then filters the vibration acceleration data to reduce noise interference. Next, using the trigonometric relationship between the accelerometer and the cable surface, the cable acceleration is decomposed to obtain the numerical relationship between the cable acceleration and the accelerometer data, thereby calculating the cable's own acceleration based on the measured data. Then, using the gravitational acceleration components of each axis of the accelerometer, the Euler angles of the accelerometer's rotation around its own xyz axes in a coordinate reference system with the cable surface as the reference can be calculated. Finally, based on the Euler angles, the rotation matrix of the accelerometer can be calculated. The rotation matrix reflects the conversion relationship between the cable vibration acceleration data and the acceleration data measured by the accelerometer, thus obtaining the cable vibration acceleration. This solves the problem in existing technologies where accurate measurement of cable vibration is impossible when the cable's position angle changes.

[0124] The above is a cable vibration measurement method provided in the embodiments of the present invention. The following is a cable vibration measurement system provided in the embodiments of the present invention.

[0125] Please see Figure 2 The cable vibration measurement system provided in this embodiment of the invention includes:

[0126] The acquisition unit 201 is used to acquire vibration acceleration data of the cable under test using the x-axis, y-axis and z-axis of the accelerometer, and to filter the vibration acceleration data.

[0127] Understandably, the acquisition unit 201 first uses an accelerometer to collect cable vibration acceleration data. Then, the vibration data collected by the accelerometer along its x, y, and z axes are filtered to reduce noise interference. The x, y, and z axes of the accelerometer refer to three predefined orthogonal coordinate axes when the accelerometer is mounted on the cable surface: the x-axis is parallel to the axial extension direction of the cable, the y-axis is perpendicular to the cable surface and points away from the cable, and the z-axis, together with the x and y axes, forms a right-handed Cartesian coordinate system. Its direction is determined by the right-hand screw rule, and it is used to characterize the sensor's attitude and orientation in space, providing a basic coordinate basis for subsequent Euler angle calculations and vibration acceleration data conversion.

[0128] The separation unit 202 is used to plot the composite acceleration based on the vibration acceleration data of the x-axis, y-axis and z-axis, and to separate the gravitational acceleration component and the cable vibration acceleration component from the composite acceleration data.

[0129] Understandably, the separation unit 202 is used to separate the gravitational acceleration component and the cable vibration acceleration component, including: firstly, drawing the composite acceleration based on the vibration acceleration data of the x-axis, y-axis and z-axis, analyzing the data of each axis of the acceleration sensor to obtain the gravitational acceleration component, and subtracting the gravitational acceleration component from the measured composite acceleration to extract the cable vibration acceleration component.

[0130] The first calculation unit 203 is used to calculate the Euler angles during the rotation of the accelerometer based on the gravitational acceleration component, and to verify the calculated Euler angles to obtain the verified Euler angles.

[0131] Understandably, the first calculation unit 203 uses the gravitational acceleration components to calculate the Euler angles (α, β, γ) of the accelerometer and verifies their rationality. The calculation of the accelerometer's Euler angles is based on the relative relationship between the gravitational acceleration components and the sensor's measurement coordinate system. Through a series of complex mathematical operations, the attitude angles of the accelerometer in three-dimensional space can be accurately obtained. The verification process ensures the accuracy of the calculation by comparing the results with expected physical laws or known conditions. The first calculation unit 203 is crucial for subsequent analysis of cable vibration characteristics because only by accurately knowing the attitude of the accelerometer can the measured acceleration be accurately converted into the actual vibration of the cable.

[0132] The construction unit 204 is used to construct a rotation matrix of cable vibration acceleration based on Euler angles to transform the accelerometer coordinate system to the cable coordinate system.

[0133] Understandably, the construction unit 204 uses the established rotation matrix and vibration acceleration data to calculate the cable's vibration acceleration in various directions, achieving precise coordinate system transformation. In other words, the rotation matrix is ​​constructed based on verified Euler angles, and the calculation process involves only basic matrix multiplication operations, requiring no complex iterative algorithms or high-order numerical processing steps. Ordinary embedded devices or low-configuration computers can complete this task quickly. Simultaneously, the logic of the coordinate system transformation is clear and intuitive, and the data processing flow is concise and compact, avoiding redundant calculation steps. This ensures the accuracy of the transformation results while significantly reducing the performance requirements of the equipment, making the coordinate transformation of cable vibration acceleration highly efficient.

[0134] The second calculation unit 205 is used to calculate the vibration acceleration of the cable on the x-axis, y-axis and z-axis based on the rotation matrix, vibration acceleration data and cable vibration acceleration components.

[0135] Understandably, the second calculation unit 205 uses the established rotation matrix and vibration acceleration data to calculate the cable's vibration acceleration in various directions, achieving precise coordinate system transformation. In other words, the key calculations in this unit only involve matrix and vector multiplication, without requiring complex mathematical libraries or extensive iterative calculations. Even embedded devices with limited computing power or older computers can complete the calculation of a single set of data within milliseconds. Furthermore, the data processing flow does not introduce redundant intermediate steps; each operation directly serves the goal of coordinate system transformation, ensuring the accuracy of the calculation results while minimizing hardware resource consumption, making the entire cable vibration acceleration calculation process efficient and easy to deploy.

[0136] In summary, the cable vibration measurement system provided by this invention first uses an accelerometer to collect vibration acceleration data of the cable under test, and then filters the vibration acceleration data to reduce noise interference. Next, using the trigonometric relationship between the accelerometer and the cable surface, the cable acceleration is decomposed to obtain the numerical relationship between the cable acceleration and the accelerometer data, thereby calculating the cable's own acceleration based on the measured data. Then, using the gravitational acceleration components of each axis of the accelerometer, the Euler angles of the accelerometer's rotation around its own xyz axes in a coordinate reference system with the cable surface as the reference can be calculated. Finally, based on the Euler angles, the rotation matrix of the accelerometer can be calculated. The rotation matrix reflects the conversion relationship between the cable vibration acceleration data and the acceleration data measured by the accelerometer, thus obtaining the cable vibration acceleration. This solves the problem in existing technologies where accurate measurement of cable vibration is impossible when the cable's position angle changes.

[0137] In one embodiment, the acquisition unit 201 is specifically used to: firstly acquire vibration acceleration data of the cable to be measured using the x-axis, y-axis and z-axis of the accelerometer and based on a preset sampling frequency; then filter the vibration acceleration data using a Kalman filter.

[0138] It should be noted that, according to relevant research, cable vibration is caused by the action of power frequency electromagnetic field, and the vibration intensity is concentrated at integer multiples of 100Hz and 50Hz. Therefore, the preset sampling frequency of this invention is ≥1000Hz. Those skilled in the art can set other sampling frequencies according to actual conditions, which are not limited here.

[0139] It should be noted that the filtering method used in this invention is Kalman filtering because Kalman filtering has the characteristics of optimal estimation and strong noise processing capabilities, which can effectively reduce the interference of noise signals.

[0140] In this embodiment, firstly, during the data acquisition stage, considering that cable vibration is mainly excited by power frequency electromagnetic fields and that vibration energy is concentrated in the 100Hz and 50Hz integer multiples of the frequency band, the preset sampling frequency is set to no less than 1000Hz according to the sampling theorem. This ensures that the high-frequency components of the vibration signal can be completely captured, avoiding signal aliasing or feature loss due to insufficient sampling frequency. Secondly, in the filtering stage, the Kalman filter algorithm, which has optimal estimation capabilities and strong noise suppression performance, is selected to process the raw acceleration data. This effectively reduces the interference of environmental noise and measurement random errors, improves the signal-to-noise ratio while preserving the true vibration characteristics, and provides a cleaner and more reliable data foundation for subsequent steps such as gravity component separation, Euler angle calculation, and coordinate transformation.

[0141] In one embodiment, the separation unit 202 separates the gravitational acceleration component and the cable vibration acceleration component from the synthesized acceleration data, including:

[0142] Several initial gravitational acceleration components are obtained by calculating the median value of the vibration amplitude over several vibration cycles. The average value of the median value of each vibration amplitude is calculated and used as the final gravitational acceleration component. The cable vibration acceleration component is obtained by subtracting the gravitational acceleration component from the synthesized acceleration.

[0143] It should be noted that all coordinate systems are set to right-handed during the calculation process. Since some accelerometer measurements are in left-handed coordinate system, they need to be converted to right-handed coordinate system. Therefore, it is only necessary to invert the z-axis data.

[0144] The specific implementation method is as follows:

[0145] Three coordinate systems are defined: the measurement coordinate system, which is the x, y, and z axis coordinate system collected by the corresponding measuring equipment; the gravity coordinate system, which is a right-handed coordinate system with the direction of gravitational acceleration as the positive z-axis; and the cable coordinate system, which is a right-handed coordinate system with the cable axis as the y-direction and the normal of the y-direction and the plane containing gravitational acceleration as the x-direction.

[0146] The total acceleration measured by the accelerometer is used to plot the composite acceleration. Clearly, because the measurement coordinate system, cable coordinate system, and gravity coordinate system are not coincident, the composite acceleration varies periodically around the component of gravitational acceleration on the z-axis of the gravity coordinate system, not around zero. By finding the maximum and minimum values ​​within a period, the median of the vibration amplitude within that period can be obtained, i.e., the gravitational acceleration component. By finding the median values ​​of multiple periods and averaging them to reduce errors, the components of gravitational acceleration on each axis can be calculated.

[0147] Subtracting the gravitational acceleration component from the composite acceleration yields the cable vibration acceleration components along the x, y, and z axes of the accelerometer. The curve shows that the cable vibration acceleration components periodically change around zero. This is understandable because, firstly, due to the accelerometer's deflection with the cable's attitude, the original composite acceleration signal contains both a constant gravitational acceleration component and a periodically fluctuating cable vibration component. Therefore, the waveform appears as a curve undulating around a non-zero bias value; the vibration is not symmetrical about zero. Secondly, by calculating the average of the median amplitudes over multiple vibration cycles and subtracting this constant gravitational bias from the composite signal, the resulting cable vibration acceleration component waveform exhibits a periodic variation around zero. This is because removing the gravitational "background" reveals the actual acceleration response of the cable reciprocating around its equilibrium position, symmetrical in both positive and negative directions, with a mean approaching zero. Finally, this phenomenon not only intuitively verifies the correctness of the gravity separation step, i.e., if the separation is incomplete, the waveform center will deviate from zero, but also provides a clean vibration data basis for subsequent inverse calculation of Euler angles based on gravity components, ensuring the accuracy of attitude calculation and coordinate transformation.

[0148] In this embodiment, it can be understood that because the sensor and cable coordinate systems do not coincide, the synthesized acceleration manifests as a periodic signal fluctuating around a certain non-zero bias (i.e., the gravity component). By obtaining the median of the maximum and minimum values ​​within a single vibration cycle, a preliminary estimate of the gravitational acceleration component within that cycle can be obtained. Then, the medians obtained from multiple cycles are averaged to obtain a more stable and accurate gravity component value. The purpose of this operation is to separate the constant gravity bias, which does not change with vibration, from the original signal, and then extract the pure cable vibration acceleration component that periodically changes around zero by subtracting this gravity component from the synthesized acceleration. This process also clarifies the definitions of the measurement, gravity, and cable coordinate systems, and points out that when the sensor uses a left-handed coordinate system, the z-axis needs to be reversed to unify it to a right-handed coordinate system, thus providing correct input data for subsequent calculation of Euler angles and coordinate transformation based on the gravity component.

[0149] In one embodiment, the first calculation unit 203 calculates the Euler angles during the rotation of the accelerometer based on the gravitational acceleration components, including:

[0150] A set of nonlinear equations is constructed based on the gravitational acceleration components, and the Euler angles during the rotation of the accelerometer are obtained by solving the set of nonlinear equations.

[0151] It should be noted that the positional relationship between the accelerometer and the cable surface can be viewed as the accelerometer rotating around its own xyz axes with the cable coordinate system as the reference coordinate system. This results in an angular relationship between the accelerometer's coordinate system and the cable coordinate system. Specifically, the direction of the cable's vibration acceleration is not equal to the direction of the acceleration measured by the accelerometer, requiring correction. Correction requires the Euler angles during the accelerometer's rotation, i.e., the angle of offset of the accelerometer relative to the cable.

[0152] For the zy plane:

[0153] ;

[0154] For the xz plane:

[0155] ;

[0156] For the xy plane:

[0157] ;

[0158] From the above, we can conclude that:

[0159] ;

[0160] In the formula, g x g y g z These represent the gravitational acceleration values ​​in the three directions, and α, β, and γ represent the deflection angles in the x, y, and z directions, respectively.

[0161] Obviously, α (yaw angle), β (pitch angle), and γ (roll angle) can be obtained by solving the nonlinear equation system. This can be done using the built-in function fsolve in MATLAB (a commercial mathematical software produced by MathWorks, a high-level technical computing language and interactive environment used for algorithm development, data visualization, data analysis, and numerical computation, mainly consisting of MATLAB and Simulink). However, the angles obtained are not unique and need to be verified to ensure their reasonableness.

[0162] Since the sensor is mounted above the cable surface, the rotation range for each angle is defined as follows: α = [-180°, 180°], β = [-90°, +90°], and γ = [-90°, +90°]. Simultaneously, since γ can be approximately 0, cos(γ) ≈ 1, sin(γ) ≈ 0. Therefore, arf = asin(-g y / g), beta=atan(-g) x / gz If human error exists during installation, preventing γ from being approximated as 0, the deflection angle can be measured using tools such as a protractor for calculation. It is understandable that when the accelerometer is mounted above the cable surface, its roll angle γ around its z-axis mainly reflects the tangential contact deviation between the sensor's bottom surface and the cable surface. Under ideal installation conditions, with the sensor's bottom surface parallel to the cable surface, γ should be close to zero. Therefore, the approximate conditions of cos(γ)≈1 and sin(γ)≈0 can be used to simplify the originally coupled nonlinear equations into analytical expressions α≈arcsin(-gy / g) and β≈arctan(-gx / gz), thereby quickly obtaining estimates of the yaw and pitch angles and reducing the complexity of numerical solutions. Meanwhile, the rotation ranges of α, β, and γ are restricted. α is [-180°, 180°], reflecting the full circumference possible in the yaw direction. β and γ are restricted to [-90°, 90°] because pitch and roll are constrained by installation geometry, preventing inversion or flipping. This range constraint eliminates inconsistencies among multiple solutions while conforming to engineering realities. If γ becomes non-negligible due to human installation errors, this fixed yaw angle can be pre-measured using tools such as a protractor and substituted into the equations as a known parameter, thus allowing the simplified solution approach to continue while ensuring calculation accuracy.

[0163] This embodiment utilizes the gravitational acceleration components separated in the previous step to inversely determine the attitude deviation angles (i.e., Euler angles α, β, γ) of the accelerometer relative to the cable coordinate system. The key is to construct a nonlinear equation system based on the distribution relationship of the gravitational components along the three axes of the sensor, and to obtain the yaw, pitch, and roll angles through numerical solutions. Since the direction of gravity remains constant in space, once the sensor tilts, the projection values ​​of gravity on each axis will change accordingly. Therefore, inversely determining the angles based on gx, gy, and gz is physically reversible. This step accurately obtains the deflection angles of the sensor caused by installation or cable positional changes, thus providing crucial positional parameters for subsequently establishing the rotation matrix and correcting the measurement data from the sensor coordinate system to the cable's own coordinate system. Furthermore, this embodiment addresses the potential for multiple solutions by constraining the angle range based on the actual installation conditions and simplifying the estimation using the condition that the roll angle is approximately zero, thereby improving the solution efficiency and the reliability of the results.

[0164] In one embodiment, the construction unit 204 is specifically used to: construct coordinate transformation matrices for rotation around the x-axis, rotation around the y-axis, and rotation around the z-axis respectively based on Euler angles, and determine the total rotation matrix based on the coordinate transformation matrices for rotation around the y-axis and rotation around the z-axis, which serves as the rotation matrix.

[0165] It should be noted that the rotation process of the accelerometer can be represented by a rotation matrix. The detailed derivation is as follows; please refer to [link / reference]. Figure 2 .

[0166] It is important to note that the order of rotation during the rotation process determines the calculation of Euler angles. The rotation order must be strictly defined, such as the X, Y, and Z axes in this case.

[0167] The positive direction is counterclockwise rotation around the x-axis, and the rotation angle is α:

[0168] ;

[0169] Similarly, rotating about the y-axis:

[0170] ;

[0171] Similarly, rotating about the z-axis:

[0172] ;

[0173] Therefore, the coordinate transformation matrix for rotation around the x-axis is:

[0174] ;

[0175] The coordinate transformation matrix for rotation about the y-axis is:

[0176] ;

[0177] The coordinate transformation matrix for rotation about the z-axis is:

[0178] ;

[0179] This embodiment, based on the Euler angles (α, β, γ) obtained in the previous step, constructs coordinate transformation matrices around each coordinate axis according to a predefined rotation order (first around the x-axis, then around the y-axis, and finally around the z-axis), and obtains the total rotation matrix through matrix multiplication. The purpose of this step is to quantitatively express the attitude deviation of the accelerometer's own coordinate system relative to the cable's coordinate system using mathematical matrix form, thus providing a coordinate transformation tool for accurately converting the acceleration data measured by the sensor to the cable's own coordinate system in subsequent steps. Since the construction of the rotation matrix depends on the rotation order of the Euler angles, this embodiment particularly emphasizes the requirement for a specific order to avoid deviations in the transformation results due to different orders, ensuring the consistency and accuracy of the final calculated cable vibration acceleration.

[0180] In one embodiment, the second computing unit 205 is specifically used for:

[0181] Based on the matrix relationship between the rotation matrix, vibration acceleration data, and cable vibration acceleration components, the cable vibration acceleration matrix is ​​obtained by solving the rotation matrix and vibration acceleration data, thereby obtaining the cable vibration acceleration on the x-axis, y-axis, and z-axis at a certain sampling time.

[0182] It should be noted that the rotation matrices [X], [Y], and [Z] obtained by the first calculation unit 203 and the construction unit 204 can yield the total rotation matrix [T] = [Z] × [Y] of the cable vibration acceleration. The vibration acceleration data (i.e., the vibration acceleration matrix [A]) obtained by the acquisition unit 201 and the cable vibration acceleration components (i.e., the cable's own vibration acceleration matrix [B]) obtained by the separation unit 202 satisfy the matrix relationship: [A] = [T] × [B]. Therefore, matrix [B] can be calculated to obtain the triaxial vibration acceleration of the cable at a certain sampling time.

[0183] ;

[0184] ;

[0185] Through the above steps, the cable's own vibration acceleration can be calculated. Integrating the vibration acceleration yields the acceleration signal; double integration of the acceleration signal yields the displacement signal. It can be understood that acceleration is the derivative of velocity with respect to time, and velocity is the derivative of displacement with respect to time; conversely, a single time integration of acceleration yields velocity, and a double integration yields displacement. After obtaining the true vibration acceleration in the cable's own coordinate system through the aforementioned steps, numerical integration methods (such as trapezoidal integration or Simpson integration) can be used to process the acceleration time series. First, the vibration velocity signal is obtained, reflecting the instantaneous speed of cable vibration; then, the velocity signal is further integrated to obtain the vibration displacement signal, reflecting the actual amplitude of the cable's deviation from its equilibrium position during vibration. It should be noted that in practical engineering applications, accelerometers exhibit zero-point drift and low-frequency noise. Direct integration can lead to the accumulation of trend terms, causing severe drift in the displacement result. Therefore, before integration, the acceleration signal usually needs to be detrended or high-pass filtered to eliminate the DC component. Once an accurate displacement signal is obtained, it can be used to assess whether cable vibration exceeds the allowable amplitude range and to determine whether there is a risk of loose joints or fatigue damage.

[0186] This embodiment utilizes the matrix relationship between the established total rotation matrix and the sensor's measured acceleration matrix to obtain the true vibration acceleration matrix in the cable's own coordinate system through matrix inverse operations. This allows for the acquisition of the cable's vibration acceleration in the x, y, and z directions at any given sampling moment. This step thoroughly corrects the measurement data, which was previously influenced by sensor attitude, to the cable's own coordinate system, completing the mathematical transformation from raw data to actual vibration. Furthermore, integrating the corrected vibration acceleration yields the vibration velocity signal, and double integration provides the vibration displacement signal, thus enabling a comprehensive assessment of the cable's vibration state.

[0187] In summary, the cable vibration measurement system provided by this invention first uses an accelerometer to collect vibration acceleration data of the cable under test, and then filters the vibration acceleration data to reduce noise interference. Next, using the trigonometric relationship between the accelerometer and the cable surface, the cable acceleration is decomposed to obtain the numerical relationship between the cable acceleration and the accelerometer data, thereby calculating the cable's own acceleration based on the measured data. Then, using the gravitational acceleration components of each axis of the accelerometer, the Euler angles of the accelerometer's rotation around its own xyz axes in a coordinate reference system with the cable surface as the reference can be calculated. Finally, based on the Euler angles, the rotation matrix of the accelerometer can be calculated. The rotation matrix reflects the conversion relationship between the cable vibration acceleration data and the acceleration data measured by the accelerometer, thus obtaining the cable vibration acceleration. This solves the problem in existing technologies where accurate measurement of cable vibration is impossible when the cable's position angle changes.

[0188] Furthermore, this embodiment of the invention also provides a cable vibration measuring device, the device including a processor and a memory:

[0189] The memory is used to store program code and transmit the program code to the processor;

[0190] The processor is used to execute the steps of the cable vibration measurement method as described in the above method embodiments, according to the instructions in the program code.

[0191] It should be noted that, in specific implementations, the cable vibration measurement device in this embodiment can be a standalone dedicated measuring instrument or a data processing module integrated into the cable online monitoring system. The processor can be implemented using a general-purpose central processing unit (CPU), microprocessor (MCU), digital signal processor (DSP), or field-programmable gate array (FPGA) chip with computing and control capabilities. The memory can include non-volatile storage media such as random access memory (RAM), read-only memory (ROM), flash memory, or hard disk, used to store program code and acceleration data, filtering parameters, intermediate variables of the rotation matrix, etc., generated during the measurement process. The device connects to the accelerometer via an interface, receives the raw vibration acceleration data collected by the sensor, and completes filtering, gravity acceleration component separation, Euler angle calculation, rotation matrix construction, and calculation of the cable's own vibration acceleration according to the steps described in the above method embodiment. Finally, the device can output the cable's three-axis vibration acceleration data in its own coordinate system, and can further integrate to obtain vibration velocity or displacement signals as needed, thereby providing an accurate basis for cable vibration state assessment.

[0192] Furthermore, this embodiment of the invention also provides a computer-readable storage medium for storing program code for executing the cable vibration measurement method described in the above method embodiments.

[0193] It should be noted that, in this embodiment, the program code stored on the computer-readable storage medium includes instructions for implementing the various steps in the aforementioned method embodiments, including but not limited to: instructions for controlling the accelerometer to collect vibration acceleration data at a preset sampling frequency, instructions for performing Kalman filtering on the collected data, instructions for separating the gravitational acceleration component and the cable vibration acceleration component from the composite acceleration, instructions for calculating Euler angles based on the gravitational acceleration component, instructions for constructing a rotation matrix, and instructions for calculating the triaxial vibration acceleration in the cable's own coordinate system.

[0194] When the program code stored in the computer-readable storage medium is loaded and executed by the processor, the computer or embedded device is able to perform the following functions: receive raw measurement data from the accelerometer; suppress noise interference through a filtering algorithm; automatically identify and separate the gravitational acceleration component to obtain the true vibration component of the cable; calculate the position angle of the sensor relative to the cable and construct a coordinate transformation matrix; and finally correct the measurement data in the sensor coordinate system to the cable's own coordinate system, and output accurate cable vibration acceleration data.

[0195] By embedding the method of this invention in the form of program code in a computer-readable storage medium, the cable vibration measurement method can be easily deployed on different types of hardware platforms, such as portable detectors, cable online monitoring terminals, industrial control computers, or cloud servers, to achieve flexible cross-platform applications.

[0196] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0197] In the embodiments provided by this invention, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces, indirect coupling or communication connection between apparatuses or units, and may be electrical, mechanical, or other forms.

[0198] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0199] Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0200] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0201] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for measuring cable vibration, characterized in that, include: Vibration acceleration data of the cable under test is acquired using the x-axis, y-axis and z-axis of an accelerometer, and the vibration acceleration data is then filtered. The composite acceleration is plotted based on the vibration acceleration data of the x-axis, y-axis and z-axis, and the gravitational acceleration component and the cable vibration acceleration component are separated from the composite acceleration data. The Euler angles during the rotation of the accelerometer are calculated based on the gravitational acceleration components, and the calculated Euler angles are verified to obtain the verified Euler angles. A rotation matrix for cable vibration acceleration is constructed based on the Euler angles to transform the accelerometer coordinate system to the cable coordinate system; Based on the rotation matrix, the vibration acceleration data, and the cable vibration acceleration components, the vibration acceleration of the cable along the x-axis, y-axis, and z-axis is calculated.

2. The cable vibration measurement method according to claim 1, characterized in that, The vibration acceleration data of the cable under test, acquired using an accelerometer along the x, y, and z axes, includes: The vibration acceleration data of the cable under test is collected using the x-axis, y-axis and z-axis of an accelerometer and based on a preset sampling frequency.

3. The cable vibration measurement method according to claim 1, characterized in that, The filtering of the vibration acceleration data includes: The vibration acceleration data were filtered using a Kalman filter.

4. The cable vibration measurement method according to claim 1, characterized in that, The separation of the gravitational acceleration component and the cable vibration acceleration component from the synthesized acceleration data includes: Several initial gravitational acceleration components are obtained by calculating the median value of the vibration amplitude over several vibration cycles. The average value of the median values ​​of each vibration amplitude is calculated and used as the final gravitational acceleration component. The cable vibration acceleration component is obtained by subtracting the gravitational acceleration component from the composite acceleration.

5. The cable vibration measurement method according to claim 1, characterized in that, The step of calculating the Euler angles during the rotation of the accelerometer based on the gravitational acceleration component includes: A set of nonlinear equations is constructed based on the gravitational acceleration components, and the Euler angles during the rotation of the accelerometer are obtained by solving the set of nonlinear equations. The nonlinear equation set is as follows: ； In the formula, g x g y g z These represent the gravitational acceleration values ​​in the three directions, and α, β, and γ represent the deflection angles in the x, y, and z directions, respectively.

6. The cable vibration measurement method according to claim 1, characterized in that, The step of constructing the rotation matrix of cable vibration acceleration based on the Euler angles includes: Based on the Euler angles, construct coordinate transformation matrices for rotation around the x-axis, the y-axis, and the z-axis, respectively. Determine the total rotation matrix based on the coordinate transformation matrices for rotation around the y-axis and the z-axis, and use this matrix as the rotation matrix.

7. The cable vibration measurement method according to claim 1, characterized in that, The calculation of the cable's vibration acceleration in various directions based on the rotation matrix, the vibration acceleration data, and the cable vibration acceleration components includes: Based on the rotation matrix, the vibration acceleration data, and the matrix relationship of the cable vibration acceleration components, the cable vibration acceleration matrix is ​​obtained by solving the rotation matrix and the vibration acceleration data, thereby obtaining the cable vibration acceleration on the x-axis, y-axis, and z-axis at a certain sampling time.

8. A cable vibration measurement system, characterized in that, include: The acquisition unit is used to acquire vibration acceleration data of the cable under test using the x-axis, y-axis and z-axis of the accelerometer, and to filter the vibration acceleration data. The separation unit is used to plot the composite acceleration based on the vibration acceleration data of the x-axis, y-axis and z-axis, and to separate the gravitational acceleration component and the cable vibration acceleration component from the composite acceleration data; The first calculation unit is used to calculate the Euler angles during the rotation of the accelerometer based on the gravitational acceleration component, and to verify the calculated Euler angles to obtain the verified Euler angles. A construction unit is used to construct a rotation matrix for the cable vibration acceleration based on the Euler angles, so as to transform the accelerometer coordinate system to the cable coordinate system; The second calculation unit is used to calculate the vibration acceleration of the cable along the x-axis, y-axis, and z-axis based on the rotation matrix, the vibration acceleration data, and the cable vibration acceleration components.

9. A cable vibration measuring device, characterized in that, The device includes a processor and a memory: The memory is used to store program code and transmit the program code to the processor; The processor is used to execute the cable vibration measurement method according to any one of claims 1-7 according to the instructions in the program code.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium is used to store program code for executing the cable vibration measurement method according to any one of claims 1-7.

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