Adjustable three-coordinate measuring system and measuring method for precision detection

Abstract

The present application relates to the field of measuring equipment, especially to a kind of adjustable three-coordinate measuring system and measuring method for precision detection, by installing piezoelectric sensing array at the connecting place of adjustable component, applying wide spectrum sweep signal, collecting vibration feedback signal, extracting structural modal characteristics, obtaining real-time collected space pose image features, determining structural dynamic parameters based on structural modal characteristics, determining space pose parameters based on space pose image features, calculating comprehensive state representation value according to structural dynamic parameters and space pose parameters and determining working condition category, generating measurement correction instruction.The present application realizes the comprehensive evaluation of the structural dynamic characteristics and space pose state of adjustable three-coordinate measuring machine, can effectively identify complex measurement working condition and adaptively adjust measurement strategy, improves the precision and reliability of precision detection, and ensures the measurement efficiency.

Description

Technical Field

[0001] This invention relates to the field of measuring equipment, and more particularly to an adjustable coordinate measuring system and method for precision inspection. Background Technology

[0002] With the rapid development of precision manufacturing technology, fields such as aerospace, new energy vehicles, and high-end equipment are placing higher demands on the accuracy and efficiency of inspecting complex components. Adjustable coordinate measuring machines (CMMs), due to their structural parameters which can be flexibly adjusted according to the dimensions of the workpiece being measured, have significant advantages in meeting the precision inspection needs of multi-variety, small-batch production models, and have gradually become a hot topic in the field of precision measurement in recent years. Further improving the measurement accuracy and intelligence level of adjustable CMMs is of great significance for ensuring the quality of high-end equipment manufacturing.

[0003] Chinese Patent Publication No. CN120846267B discloses an embodied intelligent coordinate measuring device, including a cabinet, a measuring system, and positioning clamping fixtures. The cabinet has several sets of positioning clamping fixtures arranged along its axial direction, each including multiple clamping components arranged in a circumferential array and a vacuum generator. These clamping components form a clamping space. Each clamping component includes a telescopic tube, a vacuum suction cup, an electronic valve, and a control unit. The telescopic tube has a gas flow channel along its axial direction, and its exhaust port is connected to the vacuum suction port of the vacuum generator. The vacuum suction cup is installed at the air inlet of the telescopic tube, located near the clamping space. The electronic valve is installed inside the telescopic tube to control the opening and closing of the gas flow channel. The control unit is connected to the measuring system, the telescopic tube, the vacuum generator, and the electronic valve. This measuring device's positioning clamping fixtures form a "perception-cognition-action" closed-loop control to adaptively adjust the workpiece's clamping surface.

[0004] However, the following problems still exist in the existing technology: 1. In the existing technology, the influence of the fastening state of the connection parts of each adjustable component and the distribution of structural stiffness on the measurement accuracy after the configuration adjustment of the adjustable coordinate measuring machine is completed is not considered, which leads to insufficient measurement accuracy in some cases. 2. In existing technologies, there is a lack of integrated perception of the geometric state of equipment and the vibration characteristics of the structure, which makes it difficult to achieve adaptive measurement and control under complex working conditions and reduces measurement efficiency. Summary of the Invention

[0005] Therefore, the present invention provides an adjustable coordinate measuring system and method for precision testing, which overcomes the problems in the prior art that do not consider the influence of the tightness of the connection parts of each adjustable component and the distribution of structural stiffness on the measurement accuracy after the adjustable coordinate measuring machine has completed the configuration adjustment, lack the fusion perception of the geometric state of the equipment and the vibration characteristics of the structure, resulting in insufficient measurement accuracy and low measurement efficiency in some cases.

[0006] To achieve the above objectives, the present invention provides an adjustable coordinate measuring system for precision inspection, comprising: A piezoelectric sensor array is installed at the connection of the adjustable component of the measuring equipment to apply a wide-spectrum sweep signal at a preset standard excitation interval. The structure perception and recording module is used to record the structural modal characteristics generated by the piezoelectric sensing array of the measuring device in response to the active electromagnetic excitation signal, and to acquire the spatial pose image features of the components of the measuring device in real time. The structural dynamic parameter calculation module is used to determine the structural dynamic parameters under the adjustable configuration of the measuring device based on the structural modal characteristics. The spatial pose parameter calculation module is used to determine the spatial pose parameters of the measuring device under the adjustable configuration based on the features of the spatial pose image. The classification control module is used to calculate the comprehensive state characterization value based on the structural dynamic parameters and the spatial pose parameters, and to determine the current working condition category based on the comprehensive state characterization value and the state threshold. The measurement fine-tuning module is used to generate measurement correction instructions based on the operating condition category.

[0007] Furthermore, the piezoelectric sensing array applies a wide-spectrum sweep signal at a preset standard excitation interval, including: After the measuring equipment completes the adjustable configuration adjustment, a wide-spectrum sweep signal is applied to the piezoelectric sensing array at a preset standard excitation interval; The wide-spectrum sweep signal covers the inherent frequency variation range of the adjustable configuration of the measuring device under no-load conditions, and is used to excite the structural vibration response at the connection of the adjustable components.

[0008] Furthermore, the structure-aware recording module records the structural modal features generated by the piezoelectric sensing array of the measuring device in response to the active electromagnetic excitation signal, including: The vibration feedback signal generated by the piezoelectric sensing array in response to the active electromagnetic excitation signal is collected. The vibration feedback signal is subjected to spectral analysis to extract the natural frequency and damping ratio, and the natural frequency and damping ratio are used as the structural modal features.

[0009] Furthermore, the structure-aware recording module acquires the spatial pose image features of the components of the measuring device in real time, including: During the measurement process, real-time images containing the structural features of the component itself and its surrounding environment are acquired; Feature extraction is performed on the acquired images to identify the edge contours of adjustable components and the pixel coordinates of preset feature markers; The edge contour and the pixel coordinates of the preset feature marker points are used as the spatial pose image features of the component.

[0010] Furthermore, based on the structural modal characteristics, the structural dynamic parameter calculation module determines the structural dynamic parameters under the adjustable configuration of the measuring device, including: Based on the natural frequency and the damping ratio, a comprehensive stiffness coefficient reflecting the overall stiffness of the structure under the current adjustable configuration and a connection state coefficient reflecting the tightness of the connection parts are obtained. The structural dynamic parameters are determined based on the comprehensive stiffness coefficient and the connection state coefficient.

[0011] Furthermore, the spatial pose parameter calculation module determines the spatial pose parameters of the adjustable configuration of the measuring device based on the spatial pose image features, including: Based on the pixel coordinates of the edge contour and preset feature marker points, coordinate transformation calculation is performed to obtain the actual spatial coordinates and rotation angles of each adjustable component in the world coordinate system under the current adjustable configuration, and compared with the theoretical position to calculate the spatial position deviation coefficient and attitude angle deviation coefficient of each adjustable component. Calculate the motion drift coefficient of each adjustable component based on the spatial position deviation trend of the adjustable components in multiple consecutive frames of images; The spatial pose parameters are calculated based on the spatial position deviation coefficient, the attitude angle deviation coefficient, and the motion drift coefficient.

[0012] Furthermore, the classification control module calculates the comprehensive state characterization value based on the structural dynamic parameters and the spatial pose parameters, including: The weighted sum of the structural dynamic parameters and the spatial pose parameters is used to determine the comprehensive state characterization value. The weights for the weighted summation are determined by adjusting the preset baseline weights based on the spatial pose parameters and the structural dynamic parameters.

[0013] Furthermore, the classification control module determines the current operating condition category based on the comprehensive state characterization value and the state threshold, including: If the comprehensive state characterization value is greater than or equal to the state threshold, then the current working condition category is determined to be a complex measurement working condition. If the comprehensive state characterization value is less than the state threshold, the current working condition category is determined to be normal measurement working condition. The operating conditions include conventional measurement conditions and complex measurement conditions.

[0014] Furthermore, the measurement fine-tuning module generates measurement correction instructions based on the operating condition category, including: If it is a complex measurement condition, the deceleration command and the excitation interval adjustment command are determined based on the ratio of the state threshold to the comprehensive state characterization value. The measurement correction commands include a deceleration command and an excitation interval adjustment command.

[0015] On the other hand, a measurement method for an adjustable coordinate measuring system is also provided, including, In response to the measurement device completing the adjustable configuration adjustment, an active electromagnetic excitation signal is applied to the piezoelectric sensor array installed at the connection of the adjustable component; The vibration feedback signal generated by the piezoelectric sensing array in response to the active electromagnetic excitation signal is acquired, and images including the structural features of the component itself and the surrounding environment are acquired. The vibration feedback signal is processed to extract structural modal features, and the image is processed to extract component spatial pose image features; Based on the structural modal features, the structural dynamic parameters of the measuring device under the adjustable configuration are determined, and based on the spatial pose image features of the component, the spatial pose parameters of the measuring device under the adjustable configuration are determined. A comprehensive state characterization value is obtained by calculating based on the structural dynamic parameters and the spatial pose parameters; the current working condition category is determined based on the comprehensive state characterization value and the state threshold. A measurement correction command is generated based on the operating condition category and sent to the measurement equipment for execution.

[0016] Compared with existing technologies, this invention applies a wide-spectrum sweep signal by installing a piezoelectric sensing array at the connection of adjustable components, collects vibration feedback signals to extract structural modal features, acquires real-time spatial pose image features, determines structural dynamic parameters based on structural modal features, determines spatial pose parameters based on spatial pose image features, calculates a comprehensive state characterization value based on structural dynamic parameters and spatial pose parameters, determines the working condition category, and generates measurement correction instructions. This invention achieves a comprehensive evaluation of the structural dynamic characteristics and spatial pose state of an adjustable coordinate measuring machine, effectively identifies complex measurement conditions, adaptively adjusts measurement strategies, improves the accuracy and reliability of precision testing, and ensures measurement operation efficiency.

[0017] In particular, this invention addresses the problem that existing adjustable coordinate measuring machines (CMMs) struggle to detect changes in the tightness of adjustable component connections and structural stiffness distribution in real time after configuration adjustments. During actual operation, adjustments to the position of adjustable components alter the overall mass distribution and preload at connection interfaces. Traditional fixed-parameter control models cannot respond to such changes, easily leading to structural micro-vibrations during measurement and consequently, decreased measurement accuracy. This invention addresses this by applying an active electromagnetic excitation signal to a piezoelectric sensing array embedded in the adjustable component connections, acquiring vibration feedback signals, and extracting natural frequencies and damping ratios as structural modal characteristics, thereby achieving the perception and quantification of structural dynamic characteristics.

[0018] In particular, this invention not only focuses on the vibration characteristics of the structure, but also uses a visual sensor to acquire the spatial pose image features of adjustable components in real time, identifying the pixel coordinates of edge contours and preset feature markers, thereby obtaining the actual spatial position and attitude information of the measuring device in the current adjustable configuration. In specific application scenarios, mechanical adjustments are often accompanied by minute geometric offsets or deformations. These deviations are difficult to predict completely through theoretical models, but they directly affect the positioning accuracy of precision testing. This invention, by introducing visual perception into the device's own state monitoring, achieves accurate tracking of the spatial pose of adjustable components, providing reliable data support for evaluating the current operating conditions.

[0019] In particular, this invention determines structural dynamic parameters, including comprehensive stiffness coefficients and connection state coefficients, based on structural modal characteristics. It calculates spatial position deviation coefficients, attitude angle deviation coefficients, and motion drift coefficients as spatial pose parameters based on spatial pose image features. These two types of parameters are then weighted and fused to obtain a comprehensive state characterization value. The current operating condition category is dynamically determined based on the comparison between this characterization value and a preset state threshold. In actual testing operations, the dynamic characteristics and geometric pose state of the structure jointly determine the actual operating performance of the equipment; single-dimensional monitoring is insufficient to fully reflect the true operating conditions. This invention, through fusion calculation, achieves dynamic adaptation between the measurement strategy and the actual operating state of the equipment. When a complex measurement condition is identified, a deceleration command and an excitation interval adjustment command are generated, ensuring both measurement accuracy and operational efficiency. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the module connection of an adjustable coordinate measuring system for precision inspection according to an embodiment of the present invention; Figure 2 A logic block diagram for determining the current operating condition category in an embodiment of the present invention; Figure 3 A logic block diagram for generating measurement correction instructions for embodiments of the present invention; Figure 4 This is a schematic diagram illustrating the steps of a measurement method applied to an adjustable coordinate measuring system according to an embodiment of the present invention. Detailed Implementation

[0021] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0022] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0023] It should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0024] Please see Figure 1 The diagram shown is a schematic diagram of the module connection of an adjustable coordinate measuring system for precision inspection according to an embodiment of the present invention. The adjustable coordinate measuring system for precision inspection of the present invention includes: A piezoelectric sensor array is installed at the connection of the adjustable component of the measuring equipment to apply a wide-spectrum sweep signal at a preset standard excitation interval. The structure perception and recording module is used to record the structural modal characteristics generated by the piezoelectric sensing array of the measuring device in response to the active electromagnetic excitation signal, and to acquire the spatial pose image features of the components of the measuring device in real time. The structural dynamic parameter calculation module is used to determine the structural dynamic parameters under the adjustable configuration of the measuring device based on the structural modal characteristics. The spatial pose parameter calculation module is used to determine the spatial pose parameters of the measuring device under the adjustable configuration based on the features of the spatial pose image. The classification control module is used to calculate the comprehensive state characterization value based on the structural dynamic parameters and the spatial pose parameters, and to determine the current working condition category based on the comprehensive state characterization value and the state threshold. The measurement fine-tuning module is used to generate measurement correction instructions based on the operating condition category.

[0025] Specifically, the standard excitation interval refers to a preset periodic time parameter used to control the frequency at which the piezoelectric sensing array applies a wide-spectrum sweep signal. The setting of the standard interval needs to comprehensively consider the balance between the urgency of changes in the structural dynamic characteristics and the system's operating load. An excessively short standard interval may increase the system's processing burden, while an excessively long interval may fail to capture subtle changes in the connection state after structural adjustments in a timely manner. By presetting the standard excitation interval, the system can actively trigger the acquisition of structural modal characteristics at fixed intervals during the operation of the measuring equipment, ensuring continuous monitoring of the fastening state and stiffness distribution changes at the adjustable component connections. In this embodiment of the invention, the standard excitation interval is a wide-spectrum sweep signal with a length of 500 milliseconds applied every 3500 milliseconds.

[0026] Specifically, the piezoelectric sensing array consists of multiple piezoelectric elements and multiple vibration sensors. When an electrical signal is applied, the piezoelectric elements generate mechanical vibration using the inverse piezoelectric effect to excite a structural response. When the structure vibrates, the vibration sensors convert mechanical deformation into an electrical signal output using the direct piezoelectric effect. The piezoelectric sensing array is embedded at the connection points of adjustable components, enabling it to sensitively capture minute vibration changes at the connection interface and provide raw vibration feedback signals for subsequent spectral analysis. Through the multi-point deployment of the piezoelectric sensing array, the system can acquire vibration response information from different connection points.

[0027] Specifically, this invention constructs a dual-modal sensing system covering structural vibration characteristics and spatial geometric state through the collaborative operation of a piezoelectric sensing array and a visual sensor. After the adjustable coordinate measuring machine completes its configuration adjustment, the system applies an active electromagnetic excitation signal to the piezoelectric sensing array embedded at the connection of the adjustable component, collects vibration feedback signals, and extracts the natural frequency and damping ratio as structural modal features, thereby achieving real-time perception of the structure's dynamic characteristics. It acquires real-time images containing the component's own structural features and the surrounding environment, identifies the pixel coordinates of edge contours and preset feature markers, and obtains the actual spatial position and attitude information of the measuring device under the current adjustable configuration. Based on the structural modal features, it determines the structural dynamic parameters, including the comprehensive stiffness coefficient and connection state coefficient. Based on the spatial pose image features, it calculates the spatial position deviation coefficient, attitude angle deviation coefficient, and motion drift coefficient as spatial pose parameters. Then, it weights and fuses these two types of parameters to obtain a comprehensive state characterization value. Based on the comparison result of this characterization value with a preset state threshold, it dynamically determines the current working condition category. When it is determined to be a complex measurement working condition, it generates a deceleration command and an excitation interval adjustment command. This invention enables a comprehensive evaluation of the structural dynamic characteristics and spatial pose of an adjustable coordinate measuring machine. It can effectively identify complex measurement conditions and adaptively adjust the measurement strategy, ensuring both measurement accuracy and operational efficiency.

[0028] It is understandable that this invention is particularly suitable for precision inspection scenarios in the mold and mold component manufacturing industry. Mold manufacturing is typically characterized by multi-variety, small-batch production. A single mold often contains a variety of complex components such as cavities, cores, sliders, and inserts, with diverse geometric contours and high precision requirements. Traditional measurement methods require manual adjustment of the measuring machine structure and replanning of the inspection path when changing different mold workpieces, which is not only time-consuming but also makes it difficult to guarantee measurement consistency after multiple clampings. This invention uses a piezoelectric sensor array to perceive the stiffness changes and tightness status of adjustable component connections in real time, combined with a vision sensor to track the spatial pose of the adjustable components, enabling the measuring equipment to quickly return to a stable state after frequent configuration adjustments. When the comprehensive state characterization value rises abnormally, the system automatically identifies it as a complex measurement condition and reduces the operating speed, which can reduce the impact of dynamic structural changes on the measurement results, thereby ensuring the accuracy of the detection of key dimensions such as mold surfaces, draft angles, and mating clearances.

[0029] Understandably, the inspection requirements for mold components such as guide pillars, guide sleeves, ejector pins, and cooling channels often combine standardization and customization, involving large batches and high efficiency. This invention uses a vision sensor to identify the relative positional relationship between adjustable components and workpieces in real time, automatically adjusting the measurement path with minimal manual intervention and shortening auxiliary time. When the overall state characterization value stabilizes within the normal measurement range, the system maintains a standard movement speed for measurement, balancing inspection efficiency. This adaptive control mechanism enables mold manufacturers to complete the inspection of everything from large mold blanks to precision components on a single measuring device, reducing equipment investment while improving inspection efficiency and data reliability. This provides support for quality control in the mold manufacturing process, ultimately contributing to improved mold processing accuracy and production efficiency.

[0030] Specifically, the piezoelectric sensing array applies a wide-spectrum sweep signal at a preset standard excitation interval, including: After the measuring equipment completes the adjustable configuration adjustment, a wide-spectrum sweep signal is applied to the piezoelectric sensing array at a preset standard excitation interval; The wide-spectrum sweep signal covers the inherent frequency variation range of the adjustable configuration of the measuring device under no-load conditions, and is used to excite the structural vibration response at the connection of the adjustable components.

[0031] Understandably, after adjusting the adjustable configuration, the number of standard excitation intervals should not be too few to provide sufficient sample data to ensure the reliability of structural modal feature extraction. Insufficient excitation times will make it difficult to effectively suppress random noise interference in the vibration feedback signal through statistical averaging, leading to a decrease in the accuracy of natural frequency and damping ratio identification. Excessive excitation times will prolong equipment readiness time and reduce detection efficiency. Preferably, the number of standard excitation intervals is 3 to 5, ensuring both the data redundancy required for spectrum analysis and the timeliness requirements of the measurement process.

[0032] Specifically, the structure sensing and recording module records the structural modal features generated by the piezoelectric sensing array of the measuring device in response to an active electromagnetic excitation signal, including: The vibration feedback signal generated by the piezoelectric sensing array in response to the active electromagnetic excitation signal is collected. The vibration feedback signal is subjected to spectral analysis to extract the natural frequency and damping ratio, and the natural frequency and damping ratio are used as the structural modal features.

[0033] Specifically, the structure-aware recording module acquires the spatial pose image features of the components of the measuring device in real time, including: During the measurement process, real-time images containing the structural features of the component itself and its surrounding environment are acquired; Feature extraction is performed on the acquired images to identify the edge contours of adjustable components and the pixel coordinates of preset feature markers; The edge contour and the pixel coordinates of the preset feature marker points are used as the spatial pose image features of the component.

[0034] Specifically, the measurement process is a debugging measurement process after the adjustable configuration is adjusted.

[0035] Specifically, during the measurement process, the structure perception recording module can acquire data from the optical acquisition device configured on the measuring equipment itself, or it can independently install an industrial camera according to measurement requirements. In practical applications, to ensure the accuracy and stability of image acquisition, the vision sensor should preferably be an industrial area array camera with a resolution of no less than 10 megapixels, and equipped with an appropriate light source system to ensure that the edge contours and preset feature markers of adjustable parts can be clearly identified under different lighting conditions, which will not be elaborated further.

[0036] Specifically, the aforementioned dual-modal sensing mechanism provides the monitoring data foundation for this invention. The piezoelectric sensing array acquires structural modal features through active excitation, reflecting the mechanical constraint state and energy dissipation characteristics at the connection points of adjustable components, providing a physical basis for assessing the overall structural stiffness and connection tightness. It also acquires real-time spatial pose image features of the components from the measuring equipment, characterizing the actual geometric position and orientation of the adjustable components, providing a geometric basis for identifying positional offsets and angular deflections. When a single sensing channel experiences data deviation due to sensor malfunction or environmental disturbance, the other channel can often maintain effective monitoring, reducing the risk of misjudgment and enabling the system to have more stable identification capabilities when facing complex measurement conditions.

[0037] Specifically, the structural dynamic parameter calculation module determines the structural dynamic parameters under the adjustable configuration of the measuring device based on the structural modal characteristics, including: Based on the natural frequency and the damping ratio, a comprehensive stiffness coefficient reflecting the overall stiffness of the structure under the current adjustable configuration and a connection state coefficient reflecting the tightness of the connection parts are obtained. The structural dynamic parameters are determined based on the comprehensive stiffness coefficient and the connection state coefficient.

[0038] Specifically, the comprehensive stiffness coefficient is used to characterize the overall stiffness state of the measuring device structure under the current adjustable configuration. Several pre-selected measurement conditions where the measuring device is stable and exhibits good accuracy are used as reference conditions. The natural frequencies generated by the piezoelectric sensing array in response to the active electromagnetic excitation signal under each reference condition are collected, and their arithmetic mean is calculated as the frequency standard value. In subsequent measurements, the ratio of the real-time collected natural frequencies to the frequency standard value is calculated, and the resulting ratio is the comprehensive stiffness coefficient. The closer this coefficient is to 1, the closer the overall stiffness of the current structure is to the reference stable state; if the coefficient deviates significantly from 1, it indicates a change in the structural stiffness distribution, which may affect the measurement accuracy.

[0039] Specifically, the connection state coefficient is used to characterize the tightness of the connection points of the adjustable components under the current adjustable configuration. Several pre-selected measurement conditions with stable and accurate performance of the measuring equipment are used as reference conditions. The damping ratio generated by the piezoelectric sensor array in response to the active electromagnetic excitation signal under each reference condition is collected, and its arithmetic mean is calculated as the damping standard value. In subsequent measurements, the ratio of the real-time collected damping ratio to the damping standard value is calculated, and the resulting ratio is the connection state coefficient. Changes in the damping ratio can sensitively reflect changes in the preload and friction state of the connection interface. The closer the coefficient is to 1, the closer the tightness of the connection is to the reference stable state; if the coefficient deviates significantly from 1, it indicates that the connection may be loose or the preload may have changed.

[0040] Specifically, the weighted sum of the comprehensive stiffness coefficient and the connection state coefficient is determined as the structural dynamic parameter. The weight of the comprehensive stiffness coefficient is 0.4, and the weight of the connection state coefficient is 0.6. The comprehensive stiffness coefficient reflects the overall stiffness distribution of the structure, and its variation mainly stems from changes in mass distribution caused by adjustments to the position of adjustable components. This variation has a relatively mild impact on measurement accuracy and is somewhat predictable. In contrast, the connection state coefficient reflects the tightness of the connection points of adjustable components. Minor loosening or changes in preload at the connection interface can directly trigger structural micro-vibrations, significantly affecting the real-time accuracy during dynamic measurement. Therefore, the weight of the connection state coefficient is slightly larger.

[0041] Specifically, the spatial pose parameter calculation module determines the spatial pose parameters of the measurement device under the adjustable configuration based on the spatial pose image features, including: Based on the pixel coordinates of the edge contour and preset feature marker points, coordinate transformation calculation is performed to obtain the actual spatial coordinates and rotation angles of each adjustable component in the world coordinate system under the current adjustable configuration, and compared with the theoretical position to calculate the spatial position deviation coefficient and attitude angle deviation coefficient of each adjustable component. Calculate the motion drift coefficient of each adjustable component based on the spatial position deviation trend of the adjustable components in multiple consecutive frames of images; The spatial pose parameters are calculated based on the spatial position deviation coefficient, the attitude angle deviation coefficient, and the motion drift coefficient.

[0042] Specifically, the spatial position deviation coefficient is used to characterize the degree of deviation between the actual spatial coordinates and the theoretical position of the adjustable component in the world coordinate system under the current adjustable configuration. Several pre-selected measurement conditions with stable and accurate performance of the measuring equipment are used as reference conditions. The spatial coordinates of the adjustable component, identified and calculated by a vision sensor under each reference condition, are collected, and their arithmetic mean is calculated as the standard value of the spatial position of each adjustable component. In subsequent measurements, the difference between the real-time collected and calculated actual spatial coordinates of the adjustable component and the standard value of the spatial position is calculated. The absolute value of the difference, after normalization, is the spatial position deviation coefficient. The closer this coefficient is to 0, the closer the actual position of the adjustable component is to the reference stable state.

[0043] Specifically, the attitude angle deviation coefficient is used to characterize the degree of deviation between the rotation angle of the adjustable component around each coordinate axis and the theoretical attitude under the current adjustable configuration. Several pre-selected measurement conditions with stable and accurate performance of the measuring equipment are used as reference conditions. The rotation angles of the adjustable component, identified and calculated by a vision sensor under each reference condition, are collected, and their arithmetic mean is calculated as the standard value of the attitude angle. In subsequent measurements, the difference between the actual rotation angle of the adjustable component, which is collected and calculated in real time, and the standard value of the attitude angle is calculated. The absolute value of the difference, after normalization, is the attitude angle deviation coefficient. The closer this coefficient is to 0, the closer the actual attitude of the current adjustable component is to the reference stable state.

[0044] Specifically, the motion drift coefficient is used to characterize the positional stability of the adjustable component during continuous movement in the current adjustable configuration. Several pre-selected measurement conditions with stable and accurate performance of the measuring equipment are used as benchmark conditions. The spatial position deviation trend of the adjustable component is collected from multiple consecutive frames of images under each benchmark condition. The rate of change of spatial position deviation between adjacent frames is calculated, and the statistical value of the rate of change under each benchmark condition is used as the motion drift standard value. In subsequent measurements, the rate of change of spatial position deviation between adjacent frames, collected and calculated in real time, is compared with the motion drift standard value, and the motion drift coefficient is obtained after normalization. The closer this coefficient is to 0, the higher the positional stability of the adjustable component during movement.

[0045] Specifically, the spatial pose parameter is determined by the weighted sum of the spatial position deviation coefficient, the attitude angle deviation coefficient, and the motion drift coefficient. The weighting weights for the spatial position deviation coefficient, attitude angle deviation coefficient, and motion drift coefficient are 0.3 and 0.4, respectively. The spatial position deviation coefficient and attitude angle deviation coefficient reflect the geometric pose state of the adjustable component in a static or quasi-static state. Their deviations mainly stem from positioning errors after mechanical adjustments, directly impacting the accuracy of single-point measurements. The motion drift coefficient, on the other hand, reflects the positional stability of the adjustable component during dynamic operation. Its changes directly affect the data consistency during scanning measurements or continuous point acquisition, and are particularly critical for complex surface measurement tasks requiring continuous acquisition of large amounts of point clouds. Assigning a higher weight to the motion drift coefficient allows the spatial pose parameter to more sensitively reflect stability changes during dynamic operation, thus prioritizing responses to dynamic factors affecting measurement efficiency and data quality when determining the operating condition category.

[0046] Specifically, structural dynamic parameters, through weighted fusion of comprehensive stiffness coefficients and connection state coefficients, transform the changes in structural stiffness distribution and connection interface fastening state, which are difficult to observe directly after the adjustment of adjustable components, into quantifiable numerical indicators. Spatial pose parameters, through weighted fusion of spatial position deviation coefficients, attitude angle deviation coefficients, and motion drift coefficients, further refine visual geometric pose information into a comprehensive representation reflecting static positioning accuracy and dynamic operational stability. These two types of parameters, from the perspectives of both the inherent dynamic characteristics of the structure and its external geometric state, jointly quantify the actual operating state of the adjustable measuring equipment in its current configuration, providing a reliable input basis for subsequent determination of operating condition categories.

[0047] Specifically, the classification control module calculates the comprehensive state characterization value based on the structural dynamic parameters and the spatial pose parameters, including: The difference between 1 and the spatial pose parameter is used as the spatial pose calculation parameter; The weighted sum of the structural dynamic parameters and the spatial pose calculation parameters is used to determine the comprehensive state characterization value. The weights of the weighted summation are determined by adjusting the preset baseline weights based on the spatial pose calculation parameters and the structural dynamic parameters.

[0048] Specifically, the benchmark weights are: The weighting weight of the structural dynamic parameters is 0.5, and the weighting weight of the spatial pose parameters is 0.5.

[0049] Specifically, if the difference between the spatial pose calculation parameters and the structural dynamic parameters is in the range of [-0.1, 0.1], then a preset baseline weight is used.

[0050] If the difference is greater than 0.1, the weighted average is adjusted as follows: The weighted average of the structural dynamic parameters is 0.65, and the weighted average of the spatial pose parameters is 0.35.

[0051] If the difference is less than -0.1, the weighted average is adjusted as follows: The weighted weight of the structural dynamic parameters is 0.35, and the weighted weight of the spatial pose parameters is 0.65.

[0052] Specifically, by converting spatial pose parameters into spatial pose calculation parameters aligned with the direction of structural dynamic parameters, both spatial pose calculation parameters and structural dynamic parameters participate in weighted calculations using the criterion that "the closer to 1, the better the state." Based on this, the system dynamically adjusts the weights according to the difference between the spatial pose calculation parameters and the structural dynamic parameters. When the difference exceeds the range of [-0.1, 0.1], it indicates a significant difference in the equipment state represented by the two types of parameters. In this case, the weights are shifted towards the lower value, making the comprehensive state representation value more sensitive to the factors that pose the greatest threat to measurement accuracy. This avoids the problem of one type of parameter with a better state masking the abnormality of another type of parameter under fixed weights, ensuring that the comprehensive state representation value can truly and accurately reflect the overall operating state of the equipment.

[0053] Please see Figure 2 The diagram shown is a logical block diagram of an embodiment of the present invention for determining the current operating condition category. The classification control module determines the current operating condition category based on the comprehensive state characterization value and the state threshold, including: If the comprehensive state characterization value is greater than or equal to the state threshold, then the current working condition category is determined to be a complex measurement working condition. If the comprehensive state characterization value is less than the state threshold, the current working condition category is determined to be normal measurement working condition. The operating conditions include conventional measurement conditions and complex measurement conditions.

[0054] Specifically, the state threshold is used to delineate the boundary between routine and complex measurement conditions. Its value is predetermined based on the statistical distribution of comprehensive state characterization values ​​under historical benchmark conditions. Several measurement conditions in which the measuring equipment is stable and exhibits good accuracy are pre-selected as benchmark conditions. The comprehensive state characterization values ​​corresponding to each benchmark condition are calculated according to the aforementioned method, resulting in a benchmark sample data set. The arithmetic mean and standard deviation of the sample data set are calculated, and the difference between the mean and three times the standard deviation is determined as the state threshold. By determining the state threshold through statistical methods based on benchmark data, the determination of the condition category has an objective data basis, avoiding the subjectivity of manually setting the threshold.

[0055] Please see Figure 3 The diagram shown is a logic block diagram of the measurement correction command generation method according to an embodiment of the present invention. The measurement fine-tuning module generates the measurement correction command based on the operating condition category, including: If it is a complex measurement condition, the deceleration command and the excitation interval adjustment command are determined based on the ratio of the state threshold to the comprehensive state characterization value. The measurement correction commands include a deceleration command and an excitation interval adjustment command.

[0056] Specifically, the ratio of the state threshold to the comprehensive state characterization value is determined as the speed reduction coefficient; if the speed reduction coefficient is in the range [0.9, 1.0), the reference operating speed of the measuring equipment is multiplied by the speed reduction coefficient to obtain the corrected operating speed and thus obtain the speed reduction command; If the speed reduction factor is less than 0.9, the reference operating speed of the measuring equipment is multiplied by the speed reduction factor to obtain the corrected operating speed to obtain the speed reduction command, and the standard excitation interval is replaced with the rapid excitation interval.

[0057] Specifically, the fast excitation interval is defined as applying a wide-spectrum sweep signal with a length of 250 milliseconds every 1750 milliseconds. The number of fast excitation intervals should be twice that of the corresponding standard excitation interval.

[0058] Understandably, this invention achieves refined handling of complex measurement conditions through the linkage control of the deceleration coefficient and the excitation interval. In practical applications, mold and mold component inspection often involves multiple complex curved surfaces and precise mating dimensions, requiring high positional stability and data consistency during the measurement process. When the system detects an abnormal increase in the comprehensive state characterization value due to loose connections of adjustable components or pose drift, active deceleration can effectively reduce the excitation of dynamic inertial forces on structural vibrations, suppressing further amplification of measurement errors. Simultaneously, by increasing the excitation interval, the system can more closely track the changing trends of the structural state, providing operators with real-time feedback on equipment operating quality. This adaptive control method, which couples speed control with state monitoring frequency, enables adjustable coordinate measuring machines to adjust their operating strategies to adapt to changing equipment states while maintaining basic operational continuity, thus maintaining reliable measurement accuracy even under complex conditions.

[0059] On the other hand, please see Figure 4 The diagram illustrates the steps of a measurement method applied to an adjustable coordinate measuring system according to an embodiment of the present invention. The measurement method for the adjustable coordinate measuring system includes: Step S1: In response to the measurement device completing the adjustable configuration adjustment, an active electromagnetic excitation signal is applied to the piezoelectric sensing array installed at the connection of the adjustable component; Step S2: Collect the vibration feedback signal generated by the piezoelectric sensing array in response to the active electromagnetic excitation signal, and collect images including the structural features of the component itself and the surrounding environment; Step S3: Process the vibration feedback signal to extract structural modal features, and process the image to extract component spatial pose image features; Step S4: Determine the structural dynamic parameters of the measuring device under the adjustable configuration based on the structural modal features, and determine the spatial pose parameters of the measuring device under the adjustable configuration based on the spatial pose image features of the component. Step S5: Calculate the comprehensive state characterization value based on the structural dynamic parameters and the spatial pose parameters; Step S6: Determine the current working condition category based on the comprehensive state characterization value and the state threshold; Step S7: Generate a measurement correction command based on the operating condition category and send it to the measurement device for execution.

[0060] It is understood that the measurement method proposed in this invention is particularly suitable for the mold manufacturing industry. Mold processing typically involves a variety of complex components such as cavities, cores, sliders, and inserts, and is often carried out in a multi-variety, small-batch production mode, placing high demands on the adaptability and inspection efficiency of the measuring equipment. By applying the method of this invention, the measuring equipment can quickly sense changes in the stiffness and orientation of adjustable components after changing different mold workpieces, and automatically adjust the movement speed and measurement strategy accordingly. When the comprehensive state characterization value shows that the equipment is in a stable state, it maintains high-efficiency detection; when abnormalities such as loose connections or orientation drift are detected, it actively reduces speed to ensure accuracy. This adaptive control mechanism enables mold manufacturing enterprises to complete multiple inspection tasks for various precision parts on a single measuring equipment, improving inspection efficiency, providing technical support for quality control in the mold processing process, and helping to improve the overall accuracy and production efficiency of mold manufacturing.

[0061] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. An adjustable coordinate measuring system for precision inspection, characterized in that, include: A piezoelectric sensor array is installed at the connection of the adjustable component of the measuring equipment to apply a wide-spectrum sweep signal at a preset standard excitation interval. The structure perception and recording module is used to record the structural modal characteristics generated by the piezoelectric sensing array of the measuring device in response to the active electromagnetic excitation signal, and to acquire the spatial pose image features of the components of the measuring device in real time. The structural dynamic parameter calculation module is used to determine the structural dynamic parameters under the adjustable configuration of the measuring device based on the structural modal characteristics. The spatial pose parameter calculation module is used to determine the spatial pose parameters of the measuring device under the adjustable configuration based on the features of the spatial pose image. The classification control module is used to calculate the comprehensive state characterization value based on the structural dynamic parameters and the spatial pose parameters, and to determine the current working condition category based on the comprehensive state characterization value and the state threshold. The measurement fine-tuning module is used to generate measurement correction instructions based on the operating condition category.

2. The adjustable coordinate measuring system for precision inspection according to claim 1, characterized in that, The piezoelectric sensing array applies a wide-spectrum sweep signal at a preset standard excitation interval, including... After the measuring equipment completes the adjustable configuration adjustment, a wide-spectrum sweep signal is applied to the piezoelectric sensing array at a preset standard excitation interval; The wide-spectrum sweep signal covers the inherent frequency variation range of the adjustable configuration of the measuring device under no-load conditions, and is used to excite the structural vibration response at the connection of the adjustable components.

3. The adjustable coordinate measuring system for precision inspection according to claim 1, characterized in that, The structure sensing and recording module records the structural modal characteristics generated by the piezoelectric sensing array of the measuring device in response to the active electromagnetic excitation signal, including... The vibration feedback signal generated by the piezoelectric sensing array in response to the active electromagnetic excitation signal is collected. The vibration feedback signal is subjected to spectral analysis to extract the natural frequency and damping ratio, and the natural frequency and damping ratio are used as the structural modal features.

4. The adjustable coordinate measuring system for precision inspection according to claim 1, characterized in that, The structure-aware recording module acquires real-time collected spatial pose image features of the components of the measurement equipment, including... During the measurement process, real-time images containing the structural features of the component itself and its surrounding environment are acquired; Feature extraction is performed on the acquired images to identify the edge contours of adjustable components and the pixel coordinates of preset feature markers; The edge contour and the pixel coordinates of the preset feature marker points are used as the spatial pose image features of the component.

5. The adjustable coordinate measuring system for precision inspection according to claim 3, characterized in that, Based on the structural modal characteristics, the structural dynamic parameter calculation module determines the structural dynamic parameters under the adjustable configuration of the measuring device, including: Based on the natural frequency and the damping ratio, a comprehensive stiffness coefficient reflecting the overall stiffness of the structure under the current adjustable configuration and a connection state coefficient reflecting the tightness of the connection parts are obtained. The structural dynamic parameters are determined based on the comprehensive stiffness coefficient and the connection state coefficient.

6. The adjustable coordinate measuring system for precision inspection according to claim 4, characterized in that, The spatial pose parameter calculation module determines the spatial pose parameters of the adjustable configuration of the measuring device based on the spatial pose image features. Based on the pixel coordinates of the edge contour and preset feature marker points, coordinate transformation calculation is performed to obtain the actual spatial coordinates and rotation angles of each adjustable component in the world coordinate system under the current adjustable configuration, and compared with the theoretical position to calculate the spatial position deviation coefficient and attitude angle deviation coefficient of each adjustable component. Calculate the motion drift coefficient of each adjustable component based on the spatial position deviation trend of the adjustable components in multiple consecutive frames of images; The spatial pose parameters are calculated based on the spatial position deviation coefficient, the attitude angle deviation coefficient, and the motion drift coefficient.

7. The adjustable coordinate measuring system for precision inspection according to claim 6, characterized in that, The classification control module calculates the comprehensive state characterization value based on the structural dynamic parameters and the spatial pose parameters, including: The difference between 1 and the spatial pose parameter is used as the spatial pose calculation parameter; The weighted sum of the structural dynamic parameters and the spatial pose calculation parameters is used to determine the comprehensive state characterization value. The weights of the weighted summation are determined by adjusting the preset baseline weights based on the spatial pose calculation parameters and the structural dynamic parameters.

8. The adjustable coordinate measuring system for precision inspection according to claim 7, characterized in that, The classification control module determines the current operating condition category based on the comprehensive state characterization value and the state threshold, including: If the comprehensive state characterization value is greater than or equal to the state threshold, then the current working condition category is determined to be a complex measurement working condition. If the comprehensive state characterization value is less than the state threshold, the current working condition category is determined to be normal measurement working condition. The operating conditions include conventional measurement conditions and complex measurement conditions.

9. The adjustable coordinate measuring system for precision inspection according to claim 8, characterized in that, The measurement fine-tuning module generates measurement correction instructions based on the operating condition category, including: If it is a complex measurement condition, the deceleration command and the excitation interval adjustment command are determined based on the ratio of the state threshold to the comprehensive state characterization value. The measurement correction commands include a deceleration command and an excitation interval adjustment command.

10. A measurement method applied to the adjustable coordinate measuring system for precision inspection as described in any one of claims 1-9, characterized in that, include, In response to the measurement device completing the adjustable configuration adjustment, an active electromagnetic excitation signal is applied to the piezoelectric sensor array installed at the connection of the adjustable component; The vibration feedback signal generated by the piezoelectric sensing array in response to the active electromagnetic excitation signal is acquired, and images including the structural features of the component itself and the surrounding environment are acquired. The vibration feedback signal is processed to extract structural modal features, and the image is processed to extract component spatial pose image features; Based on the structural modal features, the structural dynamic parameters of the measuring device under the adjustable configuration are determined, and based on the spatial pose image features of the component, the spatial pose parameters of the measuring device under the adjustable configuration are determined. The comprehensive state characterization value is obtained by calculating based on the structural dynamic parameters and the spatial pose parameters; The current operating condition category is determined based on the comprehensive state characterization value and the state threshold. A measurement correction command is generated based on the operating condition category and sent to the measurement equipment for execution.

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