Carbon film angle sensor segmented calibration method and system based on wear trend prediction

Abstract

The invention discloses a segmented calibration method and system for a carbon film angle sensor based on wear trend prediction, and the method comprises the steps: collecting the operation characteristic data and rated performance parameters of the carbon film angle sensor, and constructing a full-life-cycle operation database; dividing the life cycle into at least two wear stages according to the proportion of accumulated action times or the proportion of output signal deviation by combining the data and the contact type wear characteristics; environmental parameter signal drift compensation is executed in the low-wear stage, and linearity / mechanical fit deviation correction associated with the wear degree is superposed in the middle-high-wear stage; and comparing the calibrated output signal with a standard reference value, if the output signal reaches the standard, updating and storing calibration parameters, and if the output signal does not reach the standard, adjusting the parameters and repeatedly calibrating until the performance is qualified. The method prolongs the effective service life of the sensor and reduces the equipment maintenance cost.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of sensor measurement and calibration, and more particularly relates to a segmented calibration method and system for a carbon film angle sensor based on wear trend prediction. BACKGROUND

[0002] As a core measurement component in the fields of industrial automation control and engineering machinery posture monitoring, the measurement accuracy of an angle sensor directly determines the control accuracy and operation stability of the terminal equipment. Carbon film angle sensors are widely used in contact angle measurement scenarios due to their simple structure, controllable cost, and strong adaptability. The working principle of a carbon film angle sensor is mainly to convert the resistance value change to an angle signal through the sliding contact between the brush and the carbon film.

[0003] However, during long-term use, the continuous sliding contact between the brush and the carbon film of the carbon film angle sensor can cause carbon film wear. This wear process presents obvious stage characteristics. In the initial stage, micro-cutting wear of the carbon film is dominant, and the precision decay is relatively uniform. In the middle stage, accompanied by furrow wear and expansion of the shaft gap, the precision deviation shows a segmented and discrete trend. In the later stage, the carbon film fails locally, and the precision decay enters a saturation stage. Traditional calibration methods use a fixed-period full-range calibration mode, and do not develop differentiated strategies for wear stage differences. In the low wear stage, there is a waste of efficiency due to over-calibration. In the medium and high wear stages, the precision decay cannot be compensated due to insufficient calibration, making it difficult to adapt to the precision control requirements throughout the life cycle.

[0004] At the same time, environmental factors cannot be ignored in terms of their interference with calibration accuracy. Temperature fluctuations can cause changes in carbon film resistivity, humidity increases can affect the insulation performance of components, and vibration and pressure changes can exacerbate the contact gap fluctuations between the brush and the carbon film. After these environmental parameters and wear effects are superimposed, the complexity of the precision deviation is further increased. Existing technologies separate the environmental interference and wear effects for processing, and lack of coordinated consideration of the coupling effects of the two, resulting in insufficient precision stability of the calibrated sensor under complex working conditions.

[0005] The above problems cause the measurement accuracy of the carbon film angle sensor to decay rapidly during long-term service, shorten the effective service life, and increase equipment maintenance costs and downtime losses. Therefore, there is an urgent need for a precise calibration technology that can adapt to the characteristics of the wear stage and cooperatively suppress environmental interference to improve the measurement performance of the sensor throughout its life cycle. SUMMARY

[0006] The present application aims to solve the problem of traditional carbon film angle sensor calibration methods not considering wear stage differences and ignoring environmental and wear coupling interference. By accurately dividing the wear stage, developing a segmented adaptive correction strategy, and establishing a closed-loop parameter adjustment mechanism, precise calibration throughout the wear cycle is achieved, the measurement accuracy and stability of the sensor are improved, the effective service life is extended, and the equipment maintenance cost is reduced.

[0007] To address the aforementioned deficiencies or improvement needs of existing technologies, as a first aspect of this invention, the present invention provides a segmented calibration method for a carbon film angle sensor based on wear trend prediction, comprising: S1. Collect the operating characteristic data and rated performance parameters of the carbon film angle sensor to construct a full life cycle operation database for the sensor; S2. Based on the operating characteristic data and the contact wear characteristics of the carbon film angle sensor, the sensor life cycle is divided into at least two wear stages. The division is based on the ratio of the cumulative number of actions to the rated total number of actions, or the ratio of the output signal deviation to the rated accuracy. S3. Adaptively match and execute corresponding calibration strategies for each wear completion stage: For the low wear stage, perform basic interference compensation, the dimensions of which include signal drift caused by environmental parameters; For the medium to high wear stage, on the basis of performing the basic interference compensation, superimpose a precision correction strategy related to the wear degree, the correction dimensions of which include linearity deviation or mechanical fit deviation. S4. Collect the output signal of the calibrated carbon film angle sensor and compare the output signal with the standard reference value to verify whether the performance of the sensor after calibration meets the preset requirements. If it meets the preset requirements, update and store the corresponding calibration parameters. If it does not meet the preset requirements, adjust the calibration parameters for the corresponding wear stage and repeat the calibration operation until the sensor performance meets the standard.

[0008] Furthermore, the operational characteristic data in S1 includes the cumulative number of actions, the duration of a single action, real-time environmental parameters, and the output signal deviation.

[0009] Furthermore, the rated performance parameters in S1 include measurement range, accuracy index, and operating limits.

[0010] Furthermore, the process of dividing the wear stage in S2 is as follows: Construct normalized parameters for wear process Extract the cumulative number of actions taken by the sensor since it was put into use. Average load per single action Real-time operating temperature The rated total number of actions was determined during the sensor design phase through accelerated carbon film wear testing and shaft fatigue simulation. Wear coefficient under rated load Temperature effect correction function Calculations yielded The expression is: , in, This is a correction function based on the temperature characteristics of carbon film resistivity. When it rises The rate increases linearly, which aligns with the characteristic of increased wear rate of carbon film at high temperatures; Constructing accuracy attenuation sensitivity parameters Collect the real-time output signals of the sensor at different angle measurement points. Different angle measurement points cover the full range of feature points, Compared with standard angle reference value The deviation at each point was obtained by comparison. Calculate the coefficient of variation of the deviation , Used to characterize the non-uniformity of accuracy deviation caused by wear, in conjunction with the rated accuracy. get The expression is: , in, pass The standard deviation and mean were calculated, and it was found that the initial wear deviation of the carbon film angle sensor was concentrated in the high-frequency contact area. The value is relatively small; in the later stages of wear, due to localized peeling of the carbon film and uneven shaft clearance, The value increased significantly; Stage division based on dual-parameter evolution trend: real-time tracking via database and The dynamic evolution curves of the two are used to define the wear stages by utilizing the synergy of their inflection points; respectively for and Taking the first derivative, we get and Potential inflection points of two evolutionary curves are identified through derivative mutations; a cooperative threshold is set. At a certain moment satisfy When the inflection points of the two curves occur synchronously and their trends are consistent, that moment is defined as the dividing point of the wear stage, and the three stages of low wear, medium wear, and high wear are divided in turn.

[0011] Furthermore, the environmental parameters in S3 include environmental physical quantities that affect the contact state between the brush and the carbon film, the physicochemical properties of the carbon film, or the signal transmission stability under the working scenario of the carbon film angle sensor, thereby leading to measurement accuracy deviation or output signal drift.

[0012] Furthermore, the basic interference compensation process in S3 is as follows: collection Real-time values ​​of environmental interference parameters Each parameter corresponds to a preset environmental parameter, and the rated operating baseline value of each parameter is retrieved simultaneously. And the allowable fluctuation range, which includes the upper limit. and lower limit , through formula , Normalization is performed to eliminate dimensional differences, where For the first The standardized value of the interference parameter represents the relative degree to which the parameter deviates from the reference value; Then, the theoretical deviation was calculated, and the standardized interference parameter sequence was used. The input interference-signal deviation correlation model calculates the theoretical deviation of the sensor output caused by environmental interference. The model expression is: , in, For the first The single-factor influence coefficient of the interference parameter is obtained from a single-variable experiment, specifically by changing only the variable. At that time, the deviation and The slope of the linear fit; For the first Class and the The coupling influence coefficient of the interference-like parameters was obtained by orthogonal experiments, specifically by synchronously changing... , At that time, coupling deviation and The fitting coefficient; Finally, the compensation amount is generated and executed. Based on the principle that "the compensation amount and the theoretical deviation amount are equal in magnitude and opposite in direction," the basic interference compensation amount is calculated. ;Will The signal is converted into an adjustable signal that can be recognized by the signal conditioning module. The original output signal of the sensor is corrected in real time by the signal conditioning circuit to complete the basic interference compensation.

[0013] Furthermore, the accuracy correction strategy related to the degree of wear in S3 is specifically as follows: When the wear stage is classified as a low-wear stage, the signal after basic interference compensation is used as a reference, and linear correction is employed to offset the initial uniform accuracy attenuation, adapting to the wear characteristics dominated by micro-cutting in this stage; the correction formula is as follows: In the formula, The sensor output signal after correction during the low-wear stage; This is the signal after basic interference compensation; This is a linear correction factor for the low-wear stage; For normalized parameters of the wear process; When the wear stage is determined to be intermediate, a composite strategy of "interference compensation + piecewise nonlinear correction + shaft clearance compensation" is adopted to address the enhanced deviation dispersion caused by the coordinated wear of the furrow-shaft clearance at this stage. The correction formula is as follows: In the formula, The sensor output signal after correction during the intermediate wear stage; The number of segments for the full range is determined by dividing the sensor's range into characteristic measurement points. For the first Nonlinear correction coefficient; This is a parameter sensitive to accuracy attenuation. This is a segmentation identifier variable, corresponding to the first segment. The value is 1 when measuring the interval, and 0 when measuring the other intervals. This is the shaft clearance compensation coefficient; These are the measured values ​​of the shaft fit clearance; When the system is determined to be in a high-wear stage, a combined strategy of "interference compensation + local feature point calibration + global additional correction" is adopted to address the characteristics of localized carbon film failure and precision saturation. The correction formula is as follows: ; In the formula, This is the sensor output signal after correction during the high wear stage. The signal after basic interference compensation. The number of local calibration feature points and ; For the first The local deviation of each feature point takes the value of ,in, For the sensor in the first The actual output signal of each feature point The standard reference value for the corresponding feature point is obtained by a standard angle calibration device; Here are the basis functions for the Lagrange interpolation, expressed as: ; For the current measurement angle, The first The angle values ​​of each feature point; This is the global linear correction coefficient for the high wear stage.

[0014] Furthermore, the adjustment process of the corresponding stage calibration parameters in S4 is as follows: Based on the wear stage segmentation module's output, the system automatically triggers the corresponding stage's preset calibration parameter initial set; this initial set includes the core calibration coefficients for each stage and the linear correction coefficients for the low-wear stage. Piecewise nonlinear correction coefficients for the intermediate wear stage and gap compensation coefficient Characteristic point calibration coefficients during high wear stages All of these are included, and the adjustment threshold range for each parameter is clearly defined, covering the upper limit, lower limit, and single adjustment step size; Synchronously retrieve the historical calibration records of the current sensor from the sensor's full life cycle operation database, including the parameter adjustment amount each time, the accuracy deviation data before and after the adjustment, as well as the optimal calibration parameter sample of the same model sensor under the same working conditions and the parameter decay law curve of the corresponding wear stage; After parameter acquisition is complete, the real-time deviation verification and parameter initial adjustment phase begins. The current sensor output signal after correction is acquired using a standard angle calibration device. Compared with standard angle reference signal Calculate real-time deviation And compared with the preset accuracy threshold of the corresponding wear stage. Perform a comparison; like This indicates that the current calibration parameters are adapted to the wear condition, and the initial parameters should remain unchanged; if Initial parameter adjustments are performed based on the direction and magnitude of the deviation; during the low-wear phase, the coefficients are adjusted linearly. To achieve the initial adjustment, the adjustment formula is as follows: ,in Adjust the gain for the low-wear stage. The sign function is used to characterize the direction of deviation; the segmentation coefficient is adjusted synchronously during the intermediate wear stage. and gap coefficient Adjustment amount and , The two-parameter coupling values ​​are positively correlated; in the high-wear stage, the interpolation basis function weight coefficients associated with local feature points are preferentially corrected, and the initial adjustment and the measured deviation of the corresponding feature points are... Proportional; After the initial calibration is completed, the closed-loop iterative optimization and parameter solidification process begins; the calibration parameters after the initial calibration are substituted into the accuracy correction model, and the corrected signal is recalculated. And the new real-time deviation is calculated again by acquiring signals through a standard angle calibration device. ; like Then the parameter adjustment is completed and the current calibration parameters are saved to the sensor control module; if Then repeat the above initial adjustment steps, dynamically adjusting the adjustment step size according to the previous deviation change trend each time, until the real-time deviation meets the accuracy threshold requirement.

[0015] As a second aspect of the present invention, a segmented calibration system for a carbon film angle sensor based on wear trend prediction is also provided, comprising: The data acquisition unit is used to collect the operating characteristic data and rated performance parameters of the carbon film angle sensor and build a database of the sensor's entire life cycle operation. The wear stage division unit is used to divide the sensor life cycle into at least two wear stages based on the operating characteristic data and the contact wear characteristics of the carbon film angle sensor. The division is based on the ratio of the cumulative number of actions to the rated total number of actions, or the ratio of the output signal deviation to the rated accuracy. The segmented calibration strategy execution unit is used to adaptively match and execute corresponding calibration strategies for each wear completion stage: for the low wear stage, basic interference compensation is performed, the dimensions of which include signal drift caused by environmental parameters; for the medium and high wear stages, on the basis of performing the basic interference compensation, an accuracy correction strategy related to the wear degree is superimposed, the correction dimensions of which include linearity deviation or mechanical fit deviation. The calibration effect closed-loop verification unit is used to collect the output signal of the carbon film angle sensor after calibration and compare the output signal with the standard reference value to verify whether the performance of the sensor after calibration meets the preset requirements. If it meets the preset requirements, the corresponding calibration parameters are updated and stored. If it does not meet the preset requirements, the calibration parameters for the corresponding wear stage are adjusted and the calibration operation is repeated until the sensor performance meets the standard.

[0016] As a third aspect of the invention, a computer-readable storage medium is also provided, having a computer program stored thereon, the computer program being executed by a processor of any one of the following methods: a segmented calibration method for a carbon film angle sensor based on wear trend prediction.

[0017] In summary, compared with the prior art, the above-described technical solutions conceived by this invention can achieve the following beneficial effects: 1. The present invention provides a segmented calibration method for carbon film angle sensors based on wear trend prediction. This method constructs a dual-parameter co-evolution model of normalized wear process parameters and accuracy attenuation sensitivity parameters to accurately segment the contact wear stages of carbon film angle sensors. Multi-dimensional operating parameters, such as the cumulative number of sensor actions, average load per action, and real-time operating temperature, are extracted. The normalized wear process parameters are calculated by combining the rated total number of actions with a temperature influence correction function. Simultaneously, by collecting deviation data between the output signals of full-range feature points and the standard reference value, the coefficient of variation of the deviation and the percentage of the maximum deviation are calculated to obtain the accuracy attenuation sensitivity parameters. Relying on the inflection point synergy of the dual-parameter dynamic evolution curve, the wear process is clearly divided into three stages: low wear, medium wear, and high wear. Each stage directly corresponds to the carbon film wear failure mechanism, solving the problem of insufficient calibration accuracy caused by traditional calibration methods that do not consider the differences in wear stages. This provides a precise basis for the implementation of subsequent differentiated calibration strategies.

[0018] 2. The segmented calibration method for carbon film angle sensors based on wear trend prediction of this invention achieves precise compensation for accuracy attenuation at each wear stage by formulating adaptive accuracy correction strategies for different wear stages. In the low wear stage, a combined strategy of environmental compensation and basic linear correction is adopted, using linear correction coefficients to offset the uniform accuracy attenuation dominated by micro-cutting. In the medium wear stage, a composite strategy of interference compensation, segmented nonlinear correction, and shaft clearance compensation is implemented, adapting to the deviation dispersion caused by furrow-clearance co-wear through coordinated adjustment of segmented coefficients and clearance coefficients. In the high wear stage, a combined strategy of interference compensation, local feature point calibration, and global additional correction is adopted, prioritizing the correction of local failure feature point deviations and supplementing the global attenuation correction. The correction strategies for each stage are quantified through mathematical models, and the correction coefficients are calibrated through specialized experiments to ensure the scientific nature and accuracy of the correction process, significantly improving the measurement accuracy stability of the sensor throughout the entire wear cycle.

[0019] 3. The segmented calibration method for carbon film angle sensors based on wear trend prediction of the present invention achieves dynamic adaptation of calibration parameters to wear conditions by establishing a closed-loop iterative calibration parameter adjustment mechanism. Based on the wear stage division results, the initial set of preset calibration parameters for the corresponding stage is retrieved, and combined with historical calibration records of the sensor and optimal sample data of the same model, data support is provided for parameter adjustment. By real-time acquisition of the deviation between the corrected signal and the standard reference signal, the adaptability of the current calibration parameters is determined. For deviations exceeding the accuracy threshold, initial parameter adjustment is performed, and the parameters are dynamically adjusted through multiple iterations until the deviation meets the requirements. Finally, the adapted parameters are solidified and synchronized to the full lifecycle database. This adjustment mechanism realizes real-time optimization and updating of calibration parameters, avoids the problem of later accuracy decay caused by fixed parameter calibration, extends the effective service life of the sensor, and provides reusable parameter samples for the calibration of sensors of the same model. Attached Figure Description

[0020] Figure 1 This is a flowchart of the segmented calibration method for a carbon film angle sensor based on wear trend prediction according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the horizontal installation of the carbon film angle sensor according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the vertical installation of the carbon film angle sensor according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the system units in an embodiment of the present invention. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0022] Example 1 Please refer to Figure 1 This embodiment 1 provides a segmented calibration method for a carbon film angle sensor based on wear trend prediction, including: S1. Collect the operating characteristic data and rated performance parameters of the carbon film angle sensor to construct a full life cycle operation database for the sensor; S2. Based on the operating characteristic data and the contact wear characteristics of the carbon film angle sensor, the sensor life cycle is divided into at least two wear stages. The division is based on the ratio of the cumulative number of actions to the rated total number of actions, or the ratio of the output signal deviation to the rated accuracy. S3. Adaptively match and execute corresponding calibration strategies for each wear completion stage: For the low wear stage, perform basic interference compensation, the dimensions of which include signal drift caused by environmental parameters; For the medium to high wear stage, on the basis of performing the basic interference compensation, superimpose a precision correction strategy related to the wear degree, the correction dimensions of which include linearity deviation or mechanical fit deviation. S4. Collect the output signal of the calibrated carbon film angle sensor and compare the output signal with the standard reference value to verify whether the performance of the sensor after calibration meets the preset requirements. If it meets the preset requirements, update and store the corresponding calibration parameters. If it does not meet the preset requirements, adjust the calibration parameters for the corresponding wear stage and repeat the calibration operation until the sensor performance meets the standard.

[0023] like Figure 2 , Figure 3 As shown, the installation methods of the carbon film angle sensor and the motor are horizontal and vertical. The sensor is integrated with the motor through a mounting plate. Data such as the cumulative number of actions, environmental parameters, and output signal deviation generated during its operation are collected in real time and transmitted to the full life cycle operation database, providing basic data for the division of wear stages. The segmented calibration strategy of this embodiment 1 will also be directly applied to the sensor in the integrated structure. The output signal is dynamically corrected through the signal conditioning circuit. Finally, the parameter adjustment and solidification are completed by relying on the closed-loop verification mechanism to ensure the stability of the measurement accuracy of the carrier under different installation conditions and different wear stages.

[0024] Next, this embodiment 1 will further elaborate on the above steps.

[0025] (1) Data collection During long-term service, the wear process of carbon film angle sensors is closely related to their operating status. Accurate calibration requires the support of complete data throughout the entire life cycle. Therefore, the primary task is to collect the sensor's operating characteristic data and rated performance parameters, and to build a full life cycle operating database.

[0026] The data acquisition process begins as soon as the sensor is put into use. The operational characteristic data must cover key information reflecting usage intensity, operating conditions, and measurement performance: the cumulative number of actions directly relates to the frequency of sliding contact between the brush and the carbon film, and is the core indicator of wear accumulation; the duration of each action affects the frictional action time of each contact, and is directly related to the wear rate; real-time environmental parameters focus on physical quantities that may change the contact state between the brush and the carbon film, the physicochemical properties of the carbon film, or the stability of signal transmission. For example, operating temperature affects the resistivity of the carbon film, thus changing the wear rate, and humidity may affect the insulation performance of components; these parameters must be captured in real time; the output signal deviation needs to be obtained through real-time comparison with the standard angle reference value to directly reflect the attenuation of current measurement accuracy.

[0027] Rated performance parameters serve as the benchmark for data interpretation and wear assessment, and mainly include three types of core information: the measurement range clarifies the sensor's angle measurement range, which is the basis for subsequent full-range feature point selection and calibration; the accuracy index specifies the upper limit of measurement error that the sensor should achieve under different operating conditions, which is the key basis for judging the degree of accuracy degradation; and the operating limits clarify the environmental and load boundary conditions for the normal operation of the sensor, such as the maximum allowable operating temperature and maximum action load, providing a standard for subsequent analysis of the impact of operating conditions on wear.

[0028] During data acquisition, the sensor's built-in signal acquisition module, external environmental monitoring sensors, and standard calibration devices are required to achieve real-time and synchronous acquisition of various types of data. The acquired operational characteristic data are continuously recorded by timestamp, while the rated performance parameters are entered into the system before the sensor is put into use. After the two types of data are linked and stored, an operational database covering the entire lifecycle of the sensor from the initial use stage, wear development, to failure is formed, providing complete data support for subsequent wear stage division, calibration strategy formulation, and parameter adjustment.

[0029] (2) Wear stage division The core wear of carbon film angle sensors originates from the continuous sliding contact between the brush and the carbon film. This process exhibits distinct phases over time, with significant differences in the wear failure mechanisms and accuracy degradation patterns at different stages. This directly impacts the adaptability of calibration strategies. Therefore, it is necessary to combine operational characteristic data with contact wear characteristics to classify the wear stages. The classification can be based on the ratio of cumulative action counts to the rated total action counts, or the ratio of output signal deviation to rated accuracy. To improve the accuracy of the classification, stage definition should be achieved through dual-parameter co-evolution analysis.

[0030] The core of phase segmentation is constructing two key parameters and tracking their dynamic changes. The first parameter is the wear process normalization parameter, used to quantify the cumulative degree of wear. Constructing the wear process normalization parameter... The process is as follows: Extract the cumulative number of actions of the sensor since it was put into use. Average load per single action Real-time operating temperature The rated total number of actions was determined during the sensor design phase through accelerated carbon film wear testing and shaft fatigue simulation. Wear coefficient under rated load Temperature effect correction function Calculations yielded The expression is: , in, This is a correction function based on the temperature characteristics of carbon film resistivity. When it rises The wear rate increases linearly, which aligns with the characteristic of increased wear rate of carbon film at high temperatures. By comprehensively calculating these parameters, normalized parameters of the wear process are obtained, enabling unified quantification of the wear process under different working conditions.

[0031] The second parameter is the accuracy attenuation sensitivity parameter, used to characterize the non-uniformity of accuracy attenuation. When constructing this parameter, real-time output signals from feature points across the entire sensor range must be acquired to ensure that the measurement points cover the entire range and comprehensively reflect the accuracy distribution. Accuracy Attenuation Sensitivity Parameter The construction process is as follows: real-time output signals of the sensor at different angle measurement points are collected. Different angle measurement points cover the full range of feature points, Compared with standard angle reference value The deviation at each point was obtained by comparison. Calculate the coefficient of variation of the deviation , Used to characterize the non-uniformity of accuracy deviation caused by wear, in conjunction with the rated accuracy. get The quantization of accuracy attenuation characteristics is achieved, expressed as: , in, pass The standard deviation and mean were calculated, and it was found that the initial wear deviation of the carbon film angle sensor was concentrated in the high-frequency contact area. The value is relatively small; in the later stages of wear, due to localized peeling of the carbon film and uneven shaft clearance, The value increased significantly; After constructing the two parameters, their dynamic evolution curves are tracked in real time through a full lifecycle runtime database, and the wear stage is defined by the synergy of the curve inflection points. Specifically, for each parameter... and Taking the first derivative, we get and Potential inflection points between two evolution curves are identified through derivative mutations, where such mutations signify a significant change in the rate of parameter change; a cooperative threshold is set. At a certain moment satisfy When the inflection points of the two curves occur synchronously and their trends are consistent, that moment is defined as the dividing point of the wear stage, and the three stages of low wear, medium wear, and high wear are divided in turn.

[0032] (3) Implementation of segmented calibration strategy The accuracy decay mechanism, deviation source and manifestation form of carbon film angle sensors vary significantly depending on the wear stage. At the same time, environmental factors will always affect the contact state between the brush and the carbon film, the physicochemical properties of the carbon film or the stability of signal transmission, resulting in measurement accuracy deviation or output signal drift. Therefore, it is necessary to adaptively match and implement corresponding calibration strategies for each wear stage to ensure accurate calibration at different stages.

[0033] Basic interference compensation is a common foundation for calibration at all wear stages, and its core is to eliminate the drift effect of environmental parameters on the measurement signal. These environmental parameters include environmental physical quantities that affect the contact state between the brush and the carbon film, the physicochemical properties of the carbon film, or the stability of signal transmission under the operating conditions of the carbon film angle sensor, thereby leading to measurement accuracy deviations or output signal drift.

[0034] When performing basic interference compensation, the real-time values ​​of multiple environmental interference parameters are first collected. These parameters need to cover all environmental physical quantities that may cause signal drift. That is, data collection... Real-time values ​​of environmental interference parameters Each parameter corresponds to a preset environmental parameter, and the rated operating baseline value of each parameter is retrieved simultaneously. And the allowable fluctuation range, which includes the upper limit. and lower limit , through formula , Normalization is performed to eliminate dimensional differences, where For the first The standardized value of the interference parameter represents the relative degree to which the parameter deviates from the reference value; Subsequently, the theoretical deviation caused by environmental interference is calculated, and the standardized interference parameter sequence is input into a pre-defined interference-signal deviation correlation model. This model considers not only the independent influence of a single environmental parameter but also the coupling effect between different parameters; that is, the standardized interference parameter sequence... The input interference-signal deviation correlation model calculates the theoretical deviation of the sensor output caused by environmental interference. The model expression is: , in, For the first The single-factor influence coefficient of the interference parameter is obtained from a single-variable experiment, specifically by changing only the variable. At that time, the deviation and The slope of the linear fit; For the first Class and the The coupling influence coefficient of the interference-like parameters was obtained by orthogonal experiments, specifically by synchronously changing... , At that time, coupling deviation and The fitting coefficient; Finally, the compensation amount is generated and executed. Based on the principle that "the compensation amount and the theoretical deviation amount are equal in magnitude and opposite in direction," the basic interference compensation amount is calculated. ;Will The signal is converted into an adjustable signal that can be recognized by the signal conditioning module. The original output signal of the sensor is corrected in real time by the signal conditioning circuit to complete the basic interference compensation.

[0035] Based on this, differentiated accuracy correction strategies are implemented for different wear stages. Specifically, the accuracy correction strategies related to wear degree are as follows: When the wear stage is classified as a low-wear stage, the signal after basic interference compensation is used as a reference, and linear correction is employed to offset the initial uniform accuracy attenuation, adapting to the wear characteristics dominated by micro-cutting in this stage; the correction formula is as follows: In the formula, The sensor output signal after correction during the low-wear stage; This is the signal after basic interference compensation; The linear correction coefficient for the low wear stage is calibrated through accelerated carbon film micro-cutting wear test. Specifically, it is the accuracy attenuation compensation amount corresponding to the normalized parameter of unit wear process under rated working conditions. For normalized parameters of the wear process; When the wear stage is determined to be intermediate, a composite strategy of "interference compensation + piecewise nonlinear correction + shaft clearance compensation" is adopted to address the enhanced deviation dispersion caused by the coordinated wear of the furrow-shaft clearance at this stage. The correction formula is as follows: In the formula, The sensor output signal after correction during the intermediate wear stage; The number of segments for the full range is determined by dividing the sensor's range into characteristic measurement points. For the first The segment nonlinearity correction coefficient is calibrated through multi-factor orthogonal experiments to adapt to the non-uniform deviation characteristics of each segment. This is a parameter sensitive to accuracy attenuation. This is a segmentation identifier variable, corresponding to the first segment. The value is 1 when measuring the interval, and 0 when measuring the other intervals. The shaft clearance compensation coefficient is calibrated through a shaft clearance-signal deviation correlation test. These are the measured values ​​of the shaft fit clearance; When the system is determined to be in a high-wear stage, a combined strategy of "interference compensation + local feature point calibration + global additional correction" is adopted to address the characteristics of localized carbon film failure and precision saturation. The correction formula is as follows: ; In the formula, This is the sensor output signal after correction during the high wear stage. The signal after basic interference compensation. The number of local calibration feature points and Feature points are selected from the high-frequency contact area of ​​the carbon film, the local peeling feature area, and the end point of the measurement range, covering the key range of the entire measurement range; For the first The local deviation of each feature point takes the value of ,in, For the sensor in the first The actual output signal of each feature point The standard reference value for the corresponding feature point is obtained by a standard angle calibration device; Here are the basis functions for the Lagrange interpolation, expressed as: ; For the current measurement angle, The first The angle values ​​of each feature point are used to fit a local correction amount for any angle across the entire range by the feature point deviation. The coefficients are global linear correction coefficients for the high wear stage. Both are calibrated through accelerated aging tests of carbon film during the high wear stage to adapt to the accuracy decay saturation characteristics.

[0036] (4) Closed-loop verification of calibration effect After the calibration strategy is executed, closed-loop verification is required to ensure that the calibration effect meets the actual use requirements. The core is to determine whether the performance meets the standard by comparing the signal acquisition with the benchmark, and to dynamically adjust the parameters for any non-compliance until the preset accuracy requirements are met. At the same time, the effective parameters are solidified to provide support for subsequent calibrations. This process can avoid the problem of insufficient accuracy caused by fixed parameter calibration and achieve precise adaptation of calibration parameters to the wear condition of the sensor.

[0037] The verification process begins by acquiring the output signal of the calibrated carbon film angle sensor and simultaneously obtaining the standard reference value for the corresponding measurement point using a standard angle calibration device. The two values ​​are then compared to calculate the real-time deviation. Different wear stages require different accuracy levels, necessitating the setting of a preset accuracy threshold based on the stage characteristics. The real-time deviation is then compared to this threshold to determine if the calibrated performance meets the standards. If the real-time deviation is less than or equal to the preset accuracy threshold, it indicates that the current calibration parameters are suitable for the sensor's wear state, and the calibration effect meets the requirements. In this case, the parameters used in this calibration must be updated and stored in the full lifecycle operation database, along with information such as the current wear stage and calibration time, to form a complete calibration record.

[0038] If the real-time deviation exceeds the preset accuracy threshold, the calibration parameter adjustment process for the corresponding wear stage must be initiated. The specific adjustment process for the calibration parameters at the corresponding stage is as follows: Based on the wear stage segmentation module's output, the system automatically triggers the corresponding stage's preset calibration parameter initial set; this initial set includes the core calibration coefficients for each stage and the linear correction coefficients for the low-wear stage. Piecewise nonlinear correction coefficients for the intermediate wear stage and gap compensation coefficient Characteristic point calibration coefficients during high wear stages All of these are included, and the adjustment threshold range for each parameter is clearly defined, covering the upper limit, lower limit, and single adjustment step size; Synchronously retrieve the historical calibration records of the current sensor from the sensor's full life cycle operation database, including the parameter adjustment amount each time, the accuracy deviation data before and after the adjustment, as well as the optimal calibration parameter sample of the same model sensor under the same working conditions and the parameter decay law curve of the corresponding wear stage; After parameter acquisition is complete, the real-time deviation verification and parameter initial adjustment phase begins. The current sensor output signal after correction is acquired using a standard angle calibration device. Compared with standard angle reference signal Calculate real-time deviation And compared with the preset accuracy threshold of the corresponding wear stage. Perform a comparison; like This indicates that the current calibration parameters are adapted to the wear condition, and the initial parameters should remain unchanged; if Initial parameter adjustments are performed based on the direction and magnitude of the deviation; during the low-wear phase, the coefficients are adjusted linearly. To achieve the initial adjustment, the adjustment formula is as follows: ,in Adjust the gain for the low-wear stage. The sign function is used to characterize the direction of deviation; the segmentation coefficient is adjusted synchronously during the intermediate wear stage. and gap coefficient Adjustment amount and , The two-parameter coupling values ​​are positively correlated; in the high-wear stage, the interpolation basis function weight coefficients associated with local feature points are preferentially corrected, and the initial adjustment and the measured deviation of the corresponding feature points are... Proportional; After the initial calibration is completed, the closed-loop iterative optimization and parameter solidification process begins; the calibration parameters after the initial calibration are substituted into the accuracy correction model, and the corrected signal is recalculated. And the new real-time deviation is calculated again by acquiring signals through a standard angle calibration device. ; like If the parameter adjustment is completed and the current calibration parameters are saved to the sensor control module, it means that the new deviation meets the accuracy threshold requirement, the adjusted parameters are valid, and they are saved to the sensor control module to ensure that subsequent calibrations can directly use them; if If the new deviation still does not meet the standard, the initial adjustment steps are repeated, and the adjustment step size is dynamically optimized according to the deviation change trend of the previous adjustment each time. For example, if the deviation is significantly reduced after the previous adjustment, the step size can be appropriately reduced for fine adjustment. If the deviation change is not obvious, the cause needs to be analyzed and the step size or adjustment direction needs to be adjusted until the real-time deviation meets the preset accuracy threshold.

[0039] Once the parameters are finalized, all information about this adjustment, including parameter values ​​before and after the adjustment, changes in deviation, number of adjustments, and current wear stage, must be simultaneously stored in the full lifecycle operation database. This will provide historical data for subsequent calibration of the current sensor and accumulate samples for optimizing calibration parameters of the same model of sensor.

[0040] The method in Embodiment 1 has strong application adaptability in the fields of industrial automation and engineering machinery, and is particularly suitable for working scenarios where carbon film angle sensors are deployed in large numbers, such as attitude monitoring systems for engineering machinery like excavators and cranes, and angle positioning modules for automated production line equipment. In these scenarios, sensors are in a long-term service state of high-frequency operation and multiple environmental interferences. Traditional fixed-cycle calibration modes are prone to problems such as "over-calibration in the low-wear stage, wasting efficiency, and insufficient calibration in the high-wear stage, resulting in inaccuracy." However, the method in Embodiment 1, through precise division of wear stages and differentiated calibration strategies, can extend the effective service life of sensors while ensuring stable measurement accuracy, significantly reducing the frequency of equipment downtime maintenance and replacement costs, and providing core support for the continuous and stable operation of terminal equipment.

[0041] From the perspective of technology promotion and industrial value, the method of Example 1 can not only directly optimize the calibration process of carbon film angle sensors, but its core technical ideas, such as "dual-parameter definition of wear stages" and "environment-wear coupling interference compensation," can also be transferred to the calibration scenarios of other contact wear sensors, such as potentiometers and contact encoders, providing a technical paradigm for the full life cycle accuracy management of various types of sensors. With the increasing demand for intelligent equipment upgrades in the Industry 4.0 process, the requirements for long-term sensor accuracy are continuously increasing. Example 1 can be combined with an industrial internet platform to provide wear and calibration data support under real-world operating conditions for sensor design optimization through data analysis of the full life cycle operation database. This will promote the transformation of carbon film angle sensors from "passive maintenance" to "predictive calibration," helping to form an industrial closed loop of "sensor production-service-calibration-optimization," and possessing significant technological radiation effects and market promotion prospects.

[0042] Example 2 Please refer to Figure 4 This embodiment 2 provides a segmented calibration system for a carbon film angle sensor based on wear trend prediction, including: The data acquisition unit is used to collect the operating characteristic data and rated performance parameters of the carbon film angle sensor and build a database of the sensor's entire life cycle operation. The wear stage division unit is used to divide the sensor life cycle into at least two wear stages based on the operating characteristic data and the contact wear characteristics of the carbon film angle sensor. The division is based on the ratio of the cumulative number of actions to the rated total number of actions, or the ratio of the output signal deviation to the rated accuracy. The segmented calibration strategy execution unit is used to adaptively match and execute corresponding calibration strategies for each wear completion stage: for the low wear stage, basic interference compensation is performed, the dimensions of which include signal drift caused by environmental parameters; for the medium and high wear stages, on the basis of performing the basic interference compensation, an accuracy correction strategy related to the wear degree is superimposed, the correction dimensions of which include linearity deviation or mechanical fit deviation. The calibration effect closed-loop verification unit is used to collect the output signal of the carbon film angle sensor after calibration and compare the output signal with the standard reference value to verify whether the performance of the sensor after calibration meets the preset requirements. If it meets the preset requirements, the corresponding calibration parameters are updated and stored. If it does not meet the preset requirements, the calibration parameters for the corresponding wear stage are adjusted and the calibration operation is repeated until the sensor performance meets the standard.

[0043] Example 3 This embodiment 3 also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, can implement any step of a segmented calibration method for a carbon film angle sensor based on wear trend prediction.

[0044] The computer-readable storage medium may include 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.

[0045] For a description of the computer-readable storage medium provided in this application, please refer to the above method embodiments; further details will not be repeated here.

[0046] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A segmented calibration method for a carbon film angle sensor based on wear trend prediction, characterized in that, include: S1. Collect the operating characteristic data and rated performance parameters of the carbon film angle sensor to construct a full life cycle operation database for the sensor; S2. Based on the operating characteristic data and the contact wear characteristics of the carbon film angle sensor, the sensor life cycle is divided into at least two wear stages. The division is based on the ratio of the cumulative number of actions to the rated total number of actions, or the ratio of the output signal deviation to the rated accuracy. S3. Adaptively match and execute corresponding calibration strategies for each wear completion stage: For the low wear stage, perform basic interference compensation, the dimensions of which include signal drift caused by environmental parameters; For the medium to high wear stage, on the basis of performing the basic interference compensation, superimpose a precision correction strategy related to the wear degree, the correction dimensions of which include linearity deviation or mechanical fit deviation. S4. Collect the output signal of the calibrated carbon film angle sensor and compare the output signal with the standard reference value to verify whether the performance of the sensor after calibration meets the preset requirements. If it meets the preset requirements, update and store the corresponding calibration parameters. If it does not meet the preset requirements, adjust the calibration parameters for the corresponding wear stage and repeat the calibration operation until the sensor performance meets the standard.

2. The segmented calibration method for a carbon film angle sensor based on wear trend prediction according to claim 1, characterized in that, The operational characteristic data in S1 includes the cumulative number of actions, the duration of a single action, real-time environmental parameters, and the deviation of the output signal.

3. The segmented calibration method for a carbon film angle sensor based on wear trend prediction according to claim 1, characterized in that, The rated performance parameters in S1 include measurement range, accuracy index, and operating limits.

4. The segmented calibration method for a carbon film angle sensor based on wear trend prediction according to claim 1, characterized in that, The process of dividing the wear stage in S2 is as follows: Construct normalized parameters for wear process Extract the cumulative number of actions taken by the sensor since it was put into use. Average load per single action Real-time operating temperature The rated total number of actions was determined during the sensor design phase through accelerated carbon film wear testing and shaft fatigue simulation. Wear coefficient under rated load Temperature effect correction function Calculations yielded The expression is: ， in, This is a correction function based on the temperature characteristics of carbon film resistivity. When it rises The rate increases linearly, which aligns with the characteristic of increased wear rate of carbon film at high temperatures; Constructing accuracy attenuation sensitivity parameters Collect the real-time output signals of the sensor at different angle measurement points. Different angle measurement points cover the full range of feature points, Compared with standard angle reference value The deviation at each point was obtained by comparison. Calculate the coefficient of variation of the deviation , Used to characterize the non-uniformity of accuracy deviation caused by wear, in conjunction with the rated accuracy. get The expression is: ， in, pass The standard deviation and mean were calculated, and it was found that the initial wear deviation of the carbon film angle sensor was concentrated in the high-frequency contact area. The value is relatively small; in the later stages of wear, due to localized peeling of the carbon film and uneven shaft clearance, The value increased significantly; Stage division based on dual-parameter evolution trend: real-time tracking via database and The dynamic evolution curves of the two are used to define the wear stages by utilizing the synergy of their inflection points; respectively for and Taking the first derivative, we get and Potential inflection points of two evolutionary curves are identified through derivative mutations; a cooperative threshold is set. At a certain moment satisfy When the inflection points of the two curves occur synchronously and their trends are consistent, that moment is defined as the dividing point of the wear stage, and the three stages of low wear, medium wear, and high wear are divided in turn.

5. The segmented calibration method for a carbon film angle sensor based on wear trend prediction according to claim 1, characterized in that, The environmental parameters in S3 include environmental physical quantities that affect the contact state between the brush and the carbon film, the physicochemical properties of the carbon film, or the stability of signal transmission under the working scenario of the carbon film angle sensor, thereby leading to measurement accuracy deviation or output signal drift.

6. The segmented calibration method for a carbon film angle sensor based on wear trend prediction according to claim 1, characterized in that, The basic interference compensation process in S3 is as follows: collection Real-time values ​​of environmental interference parameters Each parameter corresponds to a preset environmental parameter, and the rated operating baseline value of each parameter is retrieved simultaneously. And the allowable fluctuation range, which includes the upper limit. and lower limit , through formula , Normalization is performed to eliminate dimensional differences, where For the first The standardized value of the interference parameter represents the relative degree to which the parameter deviates from the reference value; Then, the theoretical deviation was calculated, and the standardized interference parameter sequence was used. The input interference-signal deviation correlation model calculates the theoretical deviation of the sensor output caused by environmental interference. The model expression is: ， in, For the first The single-factor influence coefficient of the interference parameter is obtained from a single-variable experiment, specifically by changing only the variable. At that time, the deviation and The slope of the linear fit; For the first Class and the The coupling influence coefficient of the interference-like parameters was obtained by orthogonal experiments, specifically by synchronously changing... , At that time, coupling deviation and The fitting coefficient; Finally, the compensation amount is generated and executed. Based on the principle that "the compensation amount and the theoretical deviation amount are equal in magnitude and opposite in direction," the basic interference compensation amount is calculated. ;Will The signal is converted into an adjustable signal that can be recognized by the signal conditioning module. The original output signal of the sensor is corrected in real time by the signal conditioning circuit to complete the basic interference compensation.

7. The segmented calibration method for a carbon film angle sensor based on wear trend prediction according to claim 1, characterized in that, The accuracy correction strategy related to the degree of wear in S3 is as follows: When the wear stage is divided into the low wear stage, the signal after basic interference compensation is used as the reference, and linear correction is used to offset the initial uniform accuracy decay, which is adapted to the wear characteristics dominated by micro-cutting in this stage. The corrected formula is In the formula, The sensor output signal after correction during the low-wear stage; This is the signal after basic interference compensation; This is a linear correction factor for the low-wear stage; For normalized parameters of the wear process; When the wear stage is determined to be intermediate, a composite strategy of "interference compensation + piecewise nonlinear correction + shaft clearance compensation" is adopted to address the enhanced deviation dispersion caused by the coordinated wear of the furrow-shaft clearance at this stage. The correction formula is as follows: In the formula, The sensor output signal after correction during the intermediate wear stage; The number of segments for the full measurement range is determined by dividing the sensor's range into characteristic measurement points. For the first Nonlinear correction coefficient; This is a parameter sensitive to accuracy attenuation. This is a segmentation identifier variable, corresponding to the first segment. The value is 1 when measuring the interval, and 0 when measuring the other intervals. This is the shaft clearance compensation coefficient; These are the measured values ​​of the shaft fit clearance; When the system is determined to be in a high-wear stage, considering the characteristics of localized carbon film failure and precision saturation, a combined strategy of "interference compensation + local feature point calibration + global additional correction" is adopted. The correction formula is as follows: ; In the formula, This is the sensor output signal after correction during the high wear stage. The signal after basic interference compensation. The number of local calibration feature points and ; For the first The local deviation of each feature point takes the value of ,in, For the sensor in the first The actual output signal of each feature point The standard reference value for the corresponding feature point is obtained by a standard angle calibration device; Let be the basis function for the Lagrange interpolation, and its expression is: ; For the current measurement angle, The first The angle values ​​of each feature point; This is the global linear correction coefficient for the high wear stage.

8. The segmented calibration method for a carbon film angle sensor based on wear trend prediction according to claim 1, characterized in that, The adjustment process for the calibration parameters in the corresponding stage of S4 is as follows: Based on the wear stage segmentation module's output, the system automatically triggers the corresponding stage's preset calibration parameter initial set; this initial set includes the core calibration coefficients for each stage and the linear correction coefficients for the low-wear stage. Piecewise nonlinear correction coefficients for the intermediate wear stage and gap compensation coefficient Characteristic point calibration coefficients during high wear stages All of these are included, and the adjustment threshold range for each parameter is clearly defined, covering the upper limit, lower limit, and single adjustment step size; Synchronously retrieve the historical calibration records of the current sensor from the sensor's full life cycle operation database, including the parameter adjustment amount each time, the accuracy deviation data before and after the adjustment, as well as the optimal calibration parameter sample of the same model sensor under the same working conditions and the parameter decay law curve of the corresponding wear stage; After parameter acquisition is complete, the real-time deviation verification and parameter initial adjustment phase begins. The current sensor output signal after correction is acquired using a standard angle calibration device. Compared with standard angle reference signal Calculate real-time deviation And compared with the preset accuracy threshold of the corresponding wear stage. Perform a comparison; like This indicates that the current calibration parameters are adapted to the wear condition, and the initial parameters should remain unchanged; if Initial parameter adjustments are performed based on the direction and magnitude of the deviation; during the low-wear phase, the coefficients are adjusted linearly. To achieve the initial adjustment, the adjustment formula is as follows: ,in Adjust the gain for the low-wear stage. The sign function is used to characterize the direction of deviation; the segmentation coefficient is adjusted synchronously during the intermediate wear stage. and gap coefficient Adjustment amount and , The two-parameter coupling values ​​are positively correlated; in the high-wear stage, the interpolation basis function weight coefficients associated with local feature points are preferentially corrected, and the initial adjustment and the measured deviation of the corresponding feature points are... Proportional; After the initial calibration is completed, the closed-loop iterative optimization and parameter solidification process begins; the calibration parameters after the initial calibration are substituted into the accuracy correction model, and the corrected signal is recalculated. And the new real-time deviation is calculated again by acquiring signals through a standard angle calibration device. ; like Then the parameter adjustment is completed and the current calibration parameters are saved to the sensor control module; if Then repeat the above initial adjustment steps, dynamically adjusting the adjustment step size according to the previous deviation change trend each time, until the real-time deviation meets the accuracy threshold requirement.

9. A segmented calibration system for a carbon film angle sensor based on wear trend prediction, characterized in that, include: The data acquisition unit is used to collect the operating characteristic data and rated performance parameters of the carbon film angle sensor and build a database of the sensor's entire life cycle operation. The wear stage division unit is used to divide the sensor life cycle into at least two wear stages based on the operating characteristic data and the contact wear characteristics of the carbon film angle sensor. The division is based on the ratio of the cumulative number of actions to the rated total number of actions, or the ratio of the output signal deviation to the rated accuracy. The segmented calibration strategy execution unit is used to adaptively match and execute corresponding calibration strategies for each wear completion stage: for the low wear stage, basic interference compensation is performed, the dimensions of which include signal drift caused by environmental parameters; for the medium and high wear stages, on the basis of performing the basic interference compensation, an accuracy correction strategy related to the wear degree is superimposed, the correction dimensions of which include linearity deviation or mechanical fit deviation. The calibration effect closed-loop verification unit is used to collect the output signal of the carbon film angle sensor after calibration and compare the output signal with the standard reference value to verify whether the performance of the sensor after calibration meets the preset requirements. If it meets the preset requirements, the corresponding calibration parameters are updated and stored. If it does not meet the preset requirements, the calibration parameters for the corresponding wear stage are adjusted and the calibration operation is repeated until the sensor performance meets the standard.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, The computer program is executed by a processor as described in any one of claims 1-8: a segmented calibration method for a carbon film angle sensor based on wear trend prediction.

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