High-precision three-dimensional contour weak stiffness detection system and method for component surface

Abstract

The present invention relates to the field of contour detection technology, and specifically to a system and method for detecting low-rigidity high-precision three-dimensional contours on component surfaces. The present invention adopts a system for detecting low-rigidity high-precision three-dimensional contours on component surfaces, comprising a positioning mechanism, a probe mechanism, and a motion mechanism. The probe mechanism comprises a measuring rod, one end of which is fixed to a central measuring seat. The central measuring seat is provided with a shell that is linked to the motion mechanism. The central measuring seat is supported inside the shell by elastic members. The elastic members comprise X-direction elastic members, Y-direction elastic members, and Z-direction elastic members that are symmetrically arranged in pairs. At least one non-contact displacement sensor is provided in each of the three orthogonal directions of the central measuring seat, and a temperature sensor and a humidity sensor are provided on the shell. The present invention has the advantage of being able to significantly improve the performance and reliability of the detection system, so as to obtain high-precision and high-accuracy measurement results.

Description

Technical Field

[0001] The present invention relates to the technical field of contour detection, and in particular to a system and method for detecting the low-rigidity high-precision three-dimensional contour of a component surface. Background Art

[0002] With the development of high-tech industries and advanced manufacturing, the precision and structural complexity of components required in fields such as aerospace, semiconductors, and optoelectronics are increasing. Consequently, the measurement requirements for these components are also increasing. Precision measurement of the three-dimensional surface profile of components is an important part of the field of micro-nano measurement.

[0003] Currently, the primary instruments for precision surface profile measurement include atomic force microscopes (AFMs), scanning electron microscopes (SEMs), and ultra-high-precision 3D measuring instruments (UA3Ps). While AFMs and SEMs can accurately measure component surface topography, their limited measurement range and longitudinal measurement range make it difficult to measure components with large surface contours or large dimensions. While the UA3P can precisely measure the 3D surface profile of components, it can only measure the surface topography of simple structures and is difficult to measure complex ones.

[0004] On the other hand, the probe sensing systems mainly include optical systems, capacitive sensing systems, grating measurement systems, etc. The optical system (such as the solutions disclosed in patents with application numbers 202410931158.4 and 202311224536.7) is greatly affected by environmental changes, especially temperature changes and air flow, which affect the air density and change the refractive index of the air, thereby causing signal fluctuations in the optical system and reducing the accuracy of the probe sensing; for the capacitive sensing system, the thermal deformation of its mechanical structure has a greater impact on the signal of the sensing system, thereby reducing the overall measurement accuracy of the probe; for the grating measurement system, such as the solution disclosed in patent application number 202010685064.5, although it can perform micro-force detection, its structure is relatively complex, and the contact force of the probe still reaches 30gf-100gf, which has a greater impact on the detection results. At the same time, since an additional turntable is required to detect the side profile, the detection progress will be further reduced, and it cannot be used for precise measurement of the three-dimensional profile of the component surface. Summary of the Invention

[0005] The purpose of the present invention is to provide a component surface high-precision three-dimensional contour weak stiffness detection system that can perform three-dimensional contour detection on the component surface and has higher detection result accuracy.

[0006] To achieve the above-mentioned objectives, the present invention adopts a high-precision three-dimensional contour weak stiffness detection system for a component surface, comprising a positioning mechanism for positioning and fixing the component to be detected, a probe mechanism, and a motion mechanism for driving the probe mechanism to move, the probe mechanism comprising a measuring rod for contacting the component to be detected, one end of the measuring rod being fixed to a central measuring seat, the central measuring seat being outerly provided with a shell linked to the motion mechanism, the central measuring seat being connected and supported inside the shell by elastic members, the elastic members comprising X-direction elastic members, Y-direction elastic members, and Z-direction elastic members symmetrically arranged in pairs, the X-direction elastic members, Y-direction elastic members, and Z-direction elastic members being orthogonally arranged in pairs, at least one non-contact displacement sensor fixed to the shell is provided in each of the three orthogonal directions of the central measuring seat, and a temperature sensor and a humidity sensor for detecting the temperature and humidity of the air between the central measuring seat and the shell are provided on the shell.

[0007] The probe mechanism of the present invention is connected and supported inside the central measuring seat by elastic parts, and the X-direction elastic parts, Y-direction elastic parts and Z-direction elastic parts are arranged orthogonally in pairs, which can enable the central measuring seat with a measuring rod fixed thereon to move flexibly in three orthogonal directions, thereby expanding the measurement range and adapting to the measurement needs of components with large surface undulations or large sizes; due to the multi-directional elastic support of the elastic parts, the probe mechanism can more flexibly contact and adapt to the contours of complex structures, and in conjunction with the drive of the existing motion mechanism, it can perform three-dimensional contour detection on the surface of components of complex structures.

[0008] The present invention adopts a non-contact displacement sensor, which avoids signal fluctuations caused by changes in air density in the optical system and improves the stability of the probe sensing. By connecting and supporting the center measuring seat and the outer shell through elastic parts, the influence of thermal deformation of the mechanical structure on the signal of the sensing system is reduced, and the overall measurement accuracy of the probe mechanism is improved. The probe mechanism design of the present invention does not require an additional turntable to detect the side profile, which simplifies the structure; and the measuring rod is fixed to the center measuring seat, and the center measuring seat is connected and supported inside the outer shell through elastic parts. It is equipped with a non-contact displacement sensor to make the contact force of the probe smaller, and can even make the contact force reach the micro-newton level, so as to achieve weak rigidity contact between the end of the measuring rod and the component to be measured, thereby reducing the impact on the detection results. It can be used for high-precision measurement of the three-dimensional profile of the component surface and improve the accuracy of the detection results.

[0009] At the same time, the temperature and humidity sensors installed on the housing monitor the air temperature and humidity between the central measuring seat and the housing in real time, providing a basis for environmental compensation and precision calibration during the measurement process, further improving the accuracy of the test results. After the end of the measuring rod contacts the component and generates three-dimensional displacement, the central measuring seat also generates three-dimensional displacement due to the transmission of the elastic member. The displacement transfer matrix between the two displacements is obtained through pre-testing and recording. The displacement of the central measuring seat is obtained using a non-contact displacement sensor. This allows the displacement data of the motion mechanism driving the probe mechanism to be determined. Then, through displacement compensation, the displacement data of the measuring rod end during actual testing can be obtained, resulting in the final measurement result.

[0010] The system of the present invention offsets the deformation force caused by thermal expansion of the elastic member structure by designing a three-dimensional symmetrical elastic member structure, reducing the displacement of the center measuring seat and thus reducing the sensor's signal drift. Taking the elastic member in the X-axis as an example, the thermal deformation of the two elastic members caused by the temperature change ΔT is ɛ1 = αΔT and ɛ2 = αΔT, where α is the thermal expansion coefficient. The contact stresses generated by the thermal deformation of the two elastic members are F1 = Kɛ1 and F2 = Keq * ɛ2, respectively. Keq is the equivalent stiffness of the mechanical structure. The two contact stresses are equal in magnitude and opposite in direction. Therefore, the resultant force F = F1 + F2 = 0 at the center measuring seat, resulting in zero signal change in the non-contact displacement sensor. The three-dimensional symmetrical structure can offset the deformation force caused by the thermal expansion of the elastic members.

[0011] The system or housing should be enclosed to prevent air disturbances, thereby further improving measurement accuracy. The non-contact displacement sensor of the present invention can employ a capacitive displacement sensor, a confocal probe, or the like. The elastic member can be a spring with a relatively low stiffness. The elastic member can be positioned and secured by the preload of the elastic member and the circular grooves reserved in the housing and the central measuring seat.

[0012] Preferably, the elastic member is sleeved outside the non-contact displacement sensor.

[0013] The elastic member is sleeved outside the non-contact displacement sensor, which not only facilitates the installation and fixation of the non-contact displacement sensor and the elastic member, but also prevents the two from interfering with each other and allows the non-contact displacement sensor to be closer to the center of the central measuring seat surface.

[0014] Preferably, the central measuring seat, the housing and some components of the non-contact displacement sensor are made of materials with low thermal expansion coefficient.

[0015] The thermal expansion coefficient of the present invention can be much smaller than that of the structural materials (such as aluminum alloy) used in conventional three-dimensional contour detection systems. For example, the thermal expansion coefficient of the low thermal expansion coefficient material of the present invention can be only 1.2x10-6 The thermal expansion coefficient of conventional aluminum alloys can be one twentieth of that per degree Celsius. This invention reduces the thermal expansion of the entire probe mechanism by using low-expansion materials such as invar alloys or conductively coated glass-ceramics, thereby reducing sensor signal drift and improving detection accuracy, resulting in highly accurate test results.

[0016] Preferably, the housing is provided with a matching hole for the non-contact displacement sensor portion to pass through, and the non-contact displacement sensor portion extends to the outside of the housing.

[0017] A smaller housing is relatively less affected by changes in external ambient temperature, and its internal temperature distribution is more uniform; a smaller housing has a smaller mass, and the driving force required for the motion mechanism is smaller. The motion mechanism can drive the probe mechanism to move and adjust more quickly, thereby improving the response speed and dynamic performance of the entire detection system; the lag effect caused by its inertia is also smaller, so that the probe mechanism can follow the instructions of the motion mechanism to change position more promptly, thereby improving the real-time and coordination of the detection system; at the same time, it also facilitates the wiring or signal transmission of the non-contact displacement sensor.

[0018] Preferably, the measuring rod is arranged along the Z direction and is coaxial with the Z-direction elastic member, the measuring rod is connected below the central measuring seat, the outer shell includes a shell and a lower cover, and the lower cover is sleeved outside the measuring rod.

[0019] The measuring rod is arranged along the Z direction (vertically) and coaxial with the Z-direction elastic member. When driven by the motion mechanism, it can avoid additional bending moments and shear forces caused by eccentricity as much as possible, thereby improving the accuracy of measuring the displacement of the measuring rod. The non-contact displacement sensor can more accurately measure tiny displacement changes of the measuring rod, thereby improving the measurement accuracy of the three-dimensional contour of the component surface by the entire detection system.

[0020] Preferably, a measuring ball is provided at one end of the measuring rod away from the central measuring seat.

[0021] The stylus ball has a smaller contact area and lower contact stiffness, enabling more precise positioning of the contact point when in contact with the component being measured, helping to improve measurement accuracy and resolution. Furthermore, the stylus ball can better adapt to the complex contours and curvature variations of the component being measured, making it particularly suitable for inspecting components with complex geometries or uneven surfaces, enhancing measurement flexibility and adaptability.

[0022] The present invention discloses a measurement method using the above-mentioned component surface high-precision three-dimensional profile weak stiffness detection system, comprising the following steps:

[0023] S1. Establishing a probe displacement signal-wet temperature model;

[0024] S2. Based on the probe displacement signal obtained in step S1 - the temperature and humidity model and the real-time acquisition signals of the temperature sensor and the humidity sensor, the signal fluctuation component of the non-contact displacement sensor due to changes in ambient temperature and humidity is calculated, and the value detected by the non-contact displacement sensor is compensated online for the error;

[0025] S3. Perform a three-dimensional displacement calibration experiment on the component to be tested to obtain the displacement S measured by all non-contact displacement sensors when the center measuring base is displaced in the X, Y, and Z directions, and establish a transfer formula between the displacement of the measuring rod end and the displacement of the center measuring base;

[0026] S4. Decoupling the signal emitted by the non-contact displacement sensor according to the displacement transfer formula to obtain a measurement result including contour information;

[0027] S5. Measure the three-dimensional profile of the end of the measuring rod to obtain the topographic error of the end of the measuring rod, map the topographic error onto the surface profile of the component to be measured, establish a surface profile model of the component to be measured, perform online profile error compensation on the measurement result in step S4, and finally obtain the final measurement result after error compensation.

[0028] The method of the present invention effectively controls and corrects errors during the measurement process from multiple perspectives through multi-stage compensation, enhancing the reliability and credibility of the measurement results. It also offers the advantages of improved adaptability to complex environments and enhanced measurement capabilities for complex components. By establishing a probe displacement signal-humidity-temperature model and calculating the signal fluctuation component using real-time signals from temperature and humidity sensors, the method performs online error compensation for the non-contact displacement sensor, effectively reducing the impact of ambient temperature and humidity changes on the measurement results and significantly improving measurement accuracy. By decoupling the signals emitted by the non-contact displacement sensor, the actual displacement of the stylus end is more accurately obtained, further improving the accuracy of the measurement results. By considering the topographical errors of the stylus end and mapping them to the surface contour of the component being measured, a surface contour model is established, enabling online compensation of contour errors in the measurement results. This effectively reduces the impact of stylus end topographical errors on the measurement results, making the final measurement results more accurate and reliable. Due to manufacturing and processing errors, the stylus end / stylus ball of the present invention has extremely small irregularities, and the stylus ball is not a perfect sphere. By compensating for these stylus end topographical errors in step S5, the method further improves the accuracy of the three-dimensional contour measurement of the component being measured.

[0029] Preferably, in step S1, the change of ambient temperature is detected by arranging temperature sensors and humidity sensors, and the change of the reading of the non-contact displacement sensor is recorded at the same time. The probe displacement signal-temperature and humidity model is established by the least squares method through the recorded sample data, and the compensation value S compensation = K1T + K2H + K3, wherein K1, K2, and K3 are model coefficients obtained by the least squares method, T is the temperature value obtained by real-time detection of the temperature sensor, and H is the humidity value obtained by real-time detection of the humidity sensor.

[0030] By arranging temperature sensors and humidity sensors to detect changes in ambient temperature and humidity in real time and recording changes in the readings of the non-contact displacement sensor, a large amount of sample data can be obtained. By processing these data using the least squares method, an accurate probe displacement signal-temperature and humidity model can be established. This model can accurately reflect the impact of ambient temperature and humidity changes on the displacement sensor signal, thereby providing a reliable basis for subsequent error compensation. The compensation formula is simple and clear, and is convenient for real-time calculation and compensation. By obtaining the detection values ​​(T, H) of the temperature sensor and humidity sensor in real time and substituting them into the compensation formula, the compensation value (S 补偿 ), and based on this, online error compensation is performed on the detection values ​​of the non-contact displacement sensor, effectively reducing signal fluctuations caused by changes in ambient temperature and humidity and improving measurement accuracy. The least squares method is a mature and stable numerical method. The model coefficients (K1, K2, K3) obtained by this method have good stability and convergence, which can ensure consistent performance of the model under different measurement conditions, reducing model errors and uncertainties. The implementation of real-time compensation makes the measurement process more concise and efficient, eliminating the need for complex offline data processing and correction after measurement. Measurement personnel can directly obtain accurate and compensated measurement results, simplifying the measurement process and improving work efficiency.

[0031] Preferably, in step S3, the displacement transfer formula between the end of the measuring rod and the displacement of the central measuring seat is S 测量值 =Rx,S 测量值 It is the three-dimensional displacement of the central measuring seat detected by the non-contact displacement sensor, R is the displacement transfer matrix, and x is the three-dimensional displacement generated by the contact between the end of the measuring rod and the component.

[0032] Preferably, when a symmetrical non-contact displacement sensor is provided in the X direction or the Y direction, the final displacement value S of the central measuring seat generated in the three-dimensional direction detected by the non-contact displacement sensor is 测量值终 =(S 测量值1 -S 测量值2 ) / 2,S 测量值1 and S 测量值2 The three-dimensional displacement of the central measuring seat is detected by two symmetrically arranged non-contact displacement sensors.

[0033] Symmetrically arranged non-contact displacement sensors can effectively eliminate common-mode interference caused by environmental factors (such as temperature fluctuations and electromagnetic interference). These interferences typically affect both sensors similarly. By taking the difference and dividing by two, the impact of common-mode interference on the measurement results can be significantly reduced. By performing differential processing on the measurement values ​​of the two sensors, errors caused by individual sensor differences can be suppressed, resulting in more accurate measurement results and enabling the present invention to be used for more complex and higher-precision 3D contour detection.

[0034] The present invention provides a high-precision and highly adaptable solution for component surface three-dimensional profile detection, which is suitable for a variety of complex environments and measurement requirements. It has the advantage of significantly improving the performance and reliability of the detection system and obtaining high-precision and high-accuracy measurement results. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a cross-sectional view of the probe mechanism of the present invention.

[0036] Figure 2 It is a structural schematic diagram of the probe mechanism of the present invention with the outer shell removed.

[0037] Figure 3 It is a signal processing flow chart of the online error compensation method for surface three-dimensional contour weak stiffness detection.

[0038] Figure 4 It is a flow chart of the algorithm fitting of the relationship model between non-contact displacement sensor and temperature and humidity.

[0039] Figure 5 This is a schematic diagram of the calibration and decoupling principle of a probe system based on the coupling of a non-contact displacement sensor and an elastic member.

[0040] Figure 6 It is the principle diagram of online compensation of the probe ball surface profile of the probe system. DETAILED DESCRIPTION

[0041] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0042] Depend on Figure 1 and Figure 2As shown, this embodiment discloses a high-precision three-dimensional contour weak-rigidity detection system for component surfaces. The system comprises a positioning mechanism (not shown) for positioning and fixing the component to be inspected (not shown), a probe mechanism 100, and a motion mechanism (not shown) for moving the probe mechanism 100. The detection system of this embodiment, excluding the probe mechanism 100, can adopt the structure of any existing three-dimensional contour detection system. The probe mechanism 100 of this embodiment includes a stylus 1, the upper end of which is fixed to a central measuring seat 2, and a stylus ball 11 coaxially fixed to the lower end of the stylus 1 for contacting the component to be inspected (not shown).

[0043] The center measuring seat 2 is covered with a housing that is linked to the motion mechanism. The housing includes a shell 31 and a lower cover 32. The lower cover 32 is mounted on the outside of the measuring rod 1. The center measuring seat 2 is located in the inner cavity formed by the shell 31 and the lower cover 32. The center measuring seat 2 is connected and supported in the inner cavity of the housing by elastic members. The elastic members include X-direction elastic members 51, Y-direction elastic members 52, and Z-direction elastic members 53, which are symmetrically arranged in pairs. The X-direction elastic members 51, Y-direction elastic members 52, and Z-direction elastic members 53 are arranged orthogonally in pairs. The measuring rod 1 is arranged along the Z direction and is coaxial with the Z-direction elastic members. The measuring rod 1 is connected directly below the center of the center measuring seat 2. At least one non-contact displacement sensor 4 fixed to the housing is provided in each of the three orthogonal directions of the center measuring seat 2. The housing 31 is provided with a mating hole for the outer end of the non-contact displacement sensor to pass through. The non-contact displacement sensor portion extends to the outside of the housing.

[0044] The housing is provided with a temperature sensor and a humidity sensor (not shown) for detecting the temperature and humidity of the air between the central measuring seat 2 and the housing. The elastic member of this embodiment is a spring and is mounted outside the non-contact displacement sensor 4. The central measuring seat 2, the housing, and some components of the non-contact displacement sensor 4 are made of low-expansion alloy (invar). The non-contact displacement sensor 4 of this embodiment adopts a capacitive displacement sensor.

[0045] This embodiment discloses a measurement method using the above-mentioned component surface high-precision three-dimensional profile weak stiffness detection system, see Figures 3 to 6 , including steps S1-S5.

[0046] S1. Establish probe displacement signal-humidity temperature model. In step S1, the temperature sensor and humidity sensor are arranged to detect the change of ambient temperature, and the change of the reading of the non-contact displacement sensor is recorded at the same time. The probe displacement signal-temperature and humidity model is established by the least square method through the recorded sample data, and the compensation value S is 补偿 =K1T+K2H+K3, where K1, K2, and K3 are model coefficients obtained by the least squares method, T is the temperature value obtained by real-time detection by the temperature sensor, and H is the humidity value obtained by real-time detection by the humidity sensor.

[0047] S2. Based on the probe displacement signal-temperature and humidity model obtained in step S1 and the real-time collected signals from the temperature sensor and humidity sensor, calculate the signal fluctuation component of the non-contact displacement sensor caused by changes in ambient temperature and humidity, and perform online error compensation on the value detected by the non-contact displacement sensor.

[0048] S3. Perform a three-dimensional displacement calibration experiment on the component to be tested, obtain the displacement value S measured by all non-contact displacement sensors when the center measuring seat is displaced in the X, Y and Z directions, and establish the displacement transfer formula between the measuring ball displacement and the center measuring seat. In step S3, the displacement transfer formula between the measuring ball displacement and the center measuring seat is S 测量值 =Rx,S 测量值 The displacement in the three-dimensional direction of the center measuring seat detected by the non-contact displacement sensor is R, the displacement transfer matrix, and x, the displacement in the three-dimensional direction generated by the contact between the measuring ball and the component. When a symmetrical non-contact displacement sensor is set in the X or Y direction, the final displacement value of the three-dimensional direction generated by the center measuring seat detected by the non-contact displacement sensor is =( - ) / 2, and The displacement transfer matrix R is measured using the high-precision displacement stage included in the calibration test and detection system.

[0049] S4. According to the above displacement transfer formula, the signal emitted by the non-contact displacement sensor is decoupled to obtain a measurement result including contour information.

[0050] S5. Measure the three-dimensional profile of the stylus ball to obtain its topographic error. This topographic error is mapped onto the surface profile of the component to be measured, and a surface profile model of the component to be measured is established. The measurement results from step S4 are then subjected to online profile error compensation to obtain the final measurement result after error compensation. In step S5, by measuring a high-precision standard sphere (hereinafter referred to as the "standard sphere"), the surface profile detection error of the standard sphere can be reflected on the surface profile of the stylus ball. This surface profile detection error of the standard sphere is mapped onto the surface profile of the stylus ball using existing algorithms such as a mapping algorithm, thereby facilitating the establishment of the stylus ball surface profile model. To improve surface modeling accuracy, the standard sphere should be larger than the stylus ball. The mapping formula is α→H(α), where α is the stylus ball's movement direction and corresponds to the angle at which the stylus ball contacts the component to be measured, and H(α) is the corresponding topographic value of the stylus ball.

Claims

1. A system for detecting the low-rigidity, high-precision, three-dimensional contour of a component surface, comprising a positioning mechanism for positioning and fixing the component to be detected, a probe mechanism, and a motion mechanism for moving the probe mechanism, wherein the probe mechanism includes a probe rod for contacting the component to be detected, and characterized in that: One end of the measuring rod is fixed to the central measuring seat, and the outer cover of the central measuring seat is provided with a shell that is linked to the motion mechanism. The central measuring seat is supported inside the shell by an elastic member. The elastic member includes an X-direction elastic member, a Y-direction elastic member and a Z-direction elastic member that are symmetrically arranged in pairs. The X-direction elastic member, the Y-direction elastic member and the Z-direction elastic member are arranged orthogonally in pairs. At least one non-contact displacement sensor fixed to the shell is provided in each of the three orthogonal directions of the central measuring seat. A temperature sensor and a humidity sensor for detecting the temperature and humidity of the air between the central measuring seat and the shell are provided on the shell. The measuring rod is arranged along the Z direction and is coaxial with the Z-direction elastic member. The measuring rod is connected below the central measuring seat.

2. The component surface high-precision three-dimensional profile weak stiffness detection system according to claim 1 is characterized by: The elastic member is sleeved outside the non-contact displacement sensor.

3. The component surface high-precision three-dimensional profile weak stiffness detection system according to claim 1 or 2, characterized in that: The central measuring seat, the housing and some components of the non-contact displacement sensor are made of materials with low thermal expansion coefficient.

4. The component surface high-precision three-dimensional profile weak stiffness detection system according to claim 1, characterized in that: The housing is provided with a matching hole for the non-contact displacement sensor portion to pass through, and the non-contact displacement sensor portion extends to the outside of the housing.

5. The component surface high-precision three-dimensional profile weak stiffness detection system according to claim 1, characterized in that: The housing comprises a shell and a lower cover, and the lower cover is sleeved outside the measuring rod.

6. The component surface high-precision three-dimensional profile weak stiffness detection system according to claim 1 or 5, characterized in that: A measuring ball is provided at one end of the measuring rod away from the central measuring seat.

7. A measurement method using the component surface high-precision three-dimensional profile weak stiffness detection system according to any one of claims 1 to 6, characterized in that The steps include: S1. Establishing a probe displacement signal-wet temperature model; S2. Based on the probe displacement signal obtained in step S1 - the temperature and humidity model and the real-time acquisition signals of the temperature sensor and the humidity sensor, the signal fluctuation component of the non-contact displacement sensor due to changes in ambient temperature and humidity is calculated, and the value detected by the non-contact displacement sensor is compensated online for the error; S3. Carry out a three-dimensional displacement calibration experiment on the component to be tested, and obtain the displacement value S generated by all non-contact displacement sensors when the central measuring seat is displaced in the X, Y and Z directions. 测量值 , establish the displacement transfer formula between the end displacement of the measuring rod and the center measuring seat; S4. Decoupling the signal emitted by the non-contact displacement sensor according to the displacement transfer formula to obtain a measurement result including contour information; S5. Measure the three-dimensional profile of the end of the measuring rod to obtain the topographic error of the end of the measuring rod, map the topographic error onto the surface profile of the component to be measured, establish a surface profile model of the component to be measured, perform online profile error compensation on the measurement result in step S4, and finally obtain the final measurement result after error compensation.

8. The measuring method according to claim 7, wherein: In step S1, the temperature sensor and humidity sensor are arranged to detect the change of the ambient temperature, and the change of the reading of the non-contact displacement sensor is recorded at the same time. The probe displacement signal-temperature and humidity model is established by the least square method through the recorded sample data, and the compensation value S is 补偿 =K1T+K2H+K3, where K1, K2, and K3 are model coefficients obtained by the least squares method, T is the temperature value obtained by real-time detection by the temperature sensor, and H is the humidity value obtained by real-time detection by the humidity sensor.

9. The measuring method according to claim 7, wherein: In step S3, the displacement transfer formula between the end of the measuring rod and the center measuring seat is S 测量值 =Rx,S 测量值 It is the three-dimensional displacement of the central measuring seat detected by the non-contact displacement sensor, R is the displacement transfer matrix, and x is the three-dimensional displacement generated by the contact between the end of the measuring rod and the component.

10. The measuring method according to claim 9, characterized in that: When a symmetrical non-contact displacement sensor is set in the X direction or Y direction, the final displacement value S in the three-dimensional direction generated by the central measuring seat detected by the non-contact displacement sensor is 测量值 =(S 测量值1 -S 测量值2 ) / 2,S 测量值1 and S 测量值2 The three-dimensional displacement of the central measuring seat is detected by two symmetrically arranged non-contact displacement sensors.

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