Three-coordinate auxiliary alignment device

Abstract

The invention relates to the technical field of three-coordinate measurement, and discloses a three-coordinate auxiliary alignment device. Comprising a fixing module, a monitoring module, a processing module and a control module, the monitoring module comprises a contour acquisition unit arranged above the fixing module and a deformation acquisition unit arranged on the supporting surface of the fixing module, and the contour data of the to-be-detected workpiece and the corresponding deformation data of the supporting surface when the supporting surface is in contact with different surfaces of the to-be-detected workpiece are obtained respectively; the processing module is respectively connected with the contour acquisition unit and the deformation acquisition unit and is used for calculating a theoretical geometric center and a dynamic geometric center of the workpiece to be measured so as to obtain an actual geometric center; the control module is connected with the processing module and the fixing module and drives the fixing module to perform dynamic adjustment. The actual geometric center of the to-be-measured workpiece is solved in real time through the processing module, and the control module is combined to drive the dynamic adjustment of the fixing module, so that the geometric center of the complex workpiece is always kept unchanged during multi-surface continuous measurement, and the three-coordinate measurement precision is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of three - coordinate measurement, and specifically to a three - coordinate auxiliary alignment device. Background Art

[0002] In the field of three - coordinate measurement, the precise positioning of the geometric center of a workpiece is the core challenge to ensure measurement consistency. The traditional fixtures and alignment techniques generally have the following technical bottlenecks: When a workpiece needs to switch different contact surfaces for multi - dimensional measurement, the traditional fixtures cannot dynamically adjust the clamping position according to the force - induced deformation of each contact surface. For example, when a certain surface of the workpiece is pressed, the local support part sinks, resulting in the deviation of the geometric center. The existing technologies rely on manual intervention for repeated calibration, which is inefficient and difficult to ensure the consistency of multi - batch measurements. Moreover, the existing systems mostly rely on the theoretical geometric center of the workpiece for positioning. However, during actual clamping, due to uneven force on the contact surface between the fixture and the workpiece or material deformation (such as elastic deformation of the support part), the dynamic geometric center of the workpiece will deviate from the theoretical value. This leads to a systematic error between the theoretical model and the actual clamping state, resulting in low measurement accuracy. Summary of the Invention

[0003] The three - coordinate auxiliary alignment device provided in this application calculates the real - time actual geometric center by fusing the theoretical geometric center calculated based on the contour data of the workpiece to be measured and the dynamic geometric center calculated based on the deformation data, and combines the control module to drive the dynamic adjustment of the fixed module to eliminate the center deviation caused by clamping deformation, and keep the geometric center unchanged during continuous multi - surface measurement of complex workpieces, so as to improve its measurement accuracy. The specific solution is as follows: A three - coordinate auxiliary alignment device, the device includes: A fixed module for dynamically clamping the workpiece to be measured; A monitoring module, including a contour acquisition unit and a deformation acquisition unit; the contour acquisition unit is placed above the bearing platform of the fixed module to obtain the contour data of the workpiece to be measured; the deformation acquisition unit is placed on the support surface of the fixed module to obtain the deformation data corresponding to different surfaces of the support surface of the fixed module in contact with the workpiece to be measured; A processing module is respectively connected to the contour acquisition unit and the deformation acquisition unit. The processing module calculates the theoretical geometric center of the workpiece to be measured according to the contour data, calculates the dynamic geometric center of the workpiece to be measured when different surfaces of the workpiece are in contact with the support surface according to the deformation data, and determines the actual geometric center of the workpiece to be measured by fusing the theoretical geometric center and the dynamic geometric center; A control module is connected to the processing module and the fixed module, and drives the fixed module to perform dynamic adjustment according to the coordinates of the actual geometric center, so that when different surfaces of the workpiece to be measured are in contact with the fixed module, the geometric center is always the actual geometric center.

[0004] Preferably, the processing module fuses the theoretical geometric center and the dynamic geometric center by the least squares method to obtain the actual geometric center. The specific formula is: ; where λ is the deformation weight factor.

[0005] Preferably, the fixing module includes a bearing platform and at least three clamping mechanisms; The clamping mechanisms are radially distributed along the circumferential side of the bearing platform. Based on the theory that three points determine a plane, the support and clamping of different surfaces of the workpiece to be measured are realized. The clamping mechanism includes a telescopic arm; One end of the telescopic arm is installed on the bearing platform and rotates along the bearing platform. A support part is provided at the top of the other end of the telescopic arm. Clamping parts for the workpiece to be measured are respectively provided on both sides of the end of the telescopic arm where the support part is provided. The controller of the telescopic arm is connected to the control module; The clamping parts and the support part are respectively installed on the telescopic arm. Through the telescopic movement of the telescopic arm and its rotation around the bearing platform, different support points and clamping points for the workpiece to be measured are formed, ensuring that the coordinates of the workpiece to be measured in the two horizontal directions are the same as the coordinates of the actual geometric center in the two horizontal directions.

[0006] Preferably, the clamping part includes a mounting seat; The mounting seat is installed at the top of the support part. Holding arms are respectively provided on opposite sides of the mounting seat; One end of each holding arm is installed on both sides of the mounting seat and rotates along the connection part respectively. A clamping jaw is installed at the other end of the holding arm; The controller of the clamping jaw and the controller of the holding arm are respectively connected to the control module; The deformation acquisition unit is installed on the top of the mounting seat.

[0007] Preferably, the clamping jaw is an adjustable-opening clamping jaw.

[0008] Preferably, the clamping jaw is a pneumatic adaptive clamping jaw to adapt to the surface of the workpiece to be measured.

[0009] Preferably, the holding arm is a telescopic holding arm, which extends or contracts correspondingly according to the change in the angle between two adjacent telescopic arms to maintain the uniformity of the clamping points.

[0010] Preferably, the support part telescopically moves along the vertical direction of the telescopic arm to realize the adjustment of the workpiece to be measured in the vertical direction, ensuring that the vertical coordinate of the workpiece to be measured is the same as the vertical coordinate of the actual geometric center.

[0011] Preferably, the bearing platform includes: a seat body; An annular cavity is provided inside the seat body, and an annular sliding groove is provided on the circumferential side of the seat body; An electromagnetic ring is provided inside the annular cavity, and a slip ring is provided on the electromagnetic ring; The slip ring is sleeved outside the electromagnetic ring and slides along the length direction of the electromagnetic ring; The annular sliding groove communicates with the annular cavity; One end of the telescopic arm passes through the annular sliding groove and is connected to the electromagnetic ring. The telescopic arm is slidably connected to the annular sliding groove, and the telescopic arm moves on the electromagnetic ring through the slip ring to realize rotation around the center of the seat body; The controller of the electromagnetic ring is connected to the control module.

[0012] Preferably, the seat body includes an upper seat body and a lower seat body that are snap-connected together; Connecting bosses and connecting grooves adapted to each other are respectively provided at the centers of the opposite sides of the upper seat body and the lower seat body, and an upper annular sliding groove and a lower annular sliding groove are respectively provided on the opposite circumferential sides of the upper seat body and the lower seat body; Upper annular cavities and lower annular cavities with opposite openings are respectively provided on the circumferential sides of the connecting boss and the connecting groove. The cross-sections of the upper annular cavity and the lower annular cavity are semi-circular. The upper annular cavity and the lower annular cavity are respectively located between the upper annular sliding groove and the connecting boss, and the lower annular sliding groove and the connecting groove. The upper annular cavity and the lower annular cavity are respectively communicated with the upper annular sliding groove and the lower annular sliding groove; The upper annular sliding groove and the lower annular sliding groove form an annular sliding groove; The top and bottom of the end of the telescopic arm facing the seat body are respectively slidably connected to the upper annular sliding groove and the lower annular sliding groove.

[0013] Compared with the prior art, the beneficial effects of the present application are as follows: Through the contour acquisition unit and the deformation acquisition unit in the monitoring module, the contour data and the support surface deformation data of the workpiece to be measured are obtained respectively. The actual clamping state of the workpiece is comprehensively considered, breaking through the limitation of traditional technologies that only rely on the theoretical geometric center for positioning. The processing module calculates the theoretical geometric center based on the contour data, combines the deformation data to calculate the dynamic geometric center, and determines the actual geometric center of the workpiece to be measured by fusing the two. The determined actual geometric center highly conforms to the true state of the workpiece to be measured, solves the problem of geometric center positioning deviation caused by ignoring clamping deformation in traditional measurements, and lays a solid foundation for accurate measurement; the control module drives the fixing module to perform dynamic adjustment according to the coordinates of the actual geometric center obtained by the processing module. In actual measurement, when different surfaces of the workpiece to be measured come into contact with the fixing module, due to different force conditions, traditional fixtures cannot respond and adjust in time, resulting in geometric center deviation and further measurement errors. However, the fixing module of this device can be adjusted in real time according to the actual geometric center, ensuring that the geometric center of the workpiece to be measured remains stable during continuous multi-surface measurement. This feature effectively eliminates the center deviation caused by clamping deformation and contact surface switching, greatly improves the accuracy of coordinate measurement, and ensures the accuracy and reliability of the measurement results. This application realizes the full-process automation from data acquisition, geometric center calculation to fixing module adjustment. After the geometric center of the workpiece deviates in traditional measurement, manual intervention and repeated calibration are required, which is cumbersome and time-consuming. The technical solution of the present invention enables the measurement process to be free from frequent manual operations, greatly reducing the measurement preparation time and errors caused by human factors. Whether it is the multi-surface measurement of a single complex workpiece or the repeated measurement of multiple batches of workpieces, it can be completed efficiently and stably, significantly improving the measurement efficiency, reducing the labor cost, and enhancing the stability and consistency of the measurement process.

[0014] By setting the clamping jaws as pneumatic adaptive clamping jaws with adjustable openings to adapt to the elastic deformation characteristics of workpieces to be measured with different materials, clamping overload or loosening caused by material differences is avoided. Brief Description of the Drawings

[0015] Figure 1 It is a schematic diagram of the principle framework of the coordinate measuring auxiliary alignment device in the embodiment of the present application; Figure 2 It is a schematic diagram of the structure of the fixing module in the coordinate measuring auxiliary alignment device in the embodiment of the present application; Figure 3 It is a schematic sectional view of the bearing platform in the coordinate measuring auxiliary alignment device in the embodiment of the present application; Figure 4 It is a schematic diagram of the structure of the lower seat body in the bearing platform of the coordinate measuring auxiliary alignment device in the embodiment of the present application; Figure 5 It is a schematic diagram of the structure of the upper seat body in the bearing platform of the coordinate measuring auxiliary alignment device in the embodiment of the present application; In the figure: 1, bearing platform; 2, telescopic arm; 3, support part; 4, mounting seat; 5, holding arm; 6, jaw; 7, slip ring; 8, electromagnetic ring; 9, deformation acquisition unit; 10, annular chute; 11, upper seat body; 12, lower seat body; 13, groove wall of the connecting groove; 14, annular cavity; 15, connecting boss. Specific implementation manner

[0016] The three-coordinate auxiliary alignment device provided by this application aims to solve the problem of positioning the geometric center of a workpiece in traditional three-coordinate measurement. Through the collaborative work of multiple modules, it realizes the stability of the geometric center during the multi-face continuous measurement of complex workpieces and improves the measurement accuracy.

[0017] The three-coordinate auxiliary alignment device mainly consists of a fixed module, a monitoring module, a processing module, and a control module.

[0018] Fixed module: undertakes the dynamic clamping task of the workpiece to be measured, and is composed of a bearing platform 1 and at least three clamping mechanisms.

[0019] The bearing platform 1 includes a seat body, which is composed of an upper seat body 11 and a lower seat body 12 that are buckled. An annular cavity 14 (composed of an upper annular cavity and a lower annular cavity with a semi-circular cross-section and opposite openings) is provided inside the seat body, and an annular chute 10 (formed by an upper annular chute and a lower annular chute) is arranged on the periphery of the seat body. A connecting boss 15 (the connecting boss 15 is integrally formed with the lower seat body 12) and a connecting groove that are adapted to each other are respectively provided at the centers of the opposite sides of the upper seat body 11 and the lower seat body 12. The connecting boss 15 is inserted into the connecting groove to achieve preliminary positioning; at the same time, the groove wall 13 of the connecting groove is inserted into the depressions on both sides of the connecting boss to further enhance the positioning effect. Then, it is fixed by bolts to complete the connection of the upper seat body 11 and the lower seat body 12. An electromagnetic ring 8 is arranged inside the annular cavity 14, and a slip ring 7 that is in one-to-one correspondence with the number of telescopic arms 2 is sleeved on the electromagnetic ring 8, and the slip ring 7 can slide along the length direction of the electromagnetic ring 8.

[0020] The clamping mechanisms are radially distributed along the periphery of the bearing platform 1. Each clamping mechanism includes two telescopic arms 2, a support part 3, and a clamping member. One end of the telescopic arm 2 is installed on the bearing platform 1, passes through the annular chute 10 and is connected to the slip ring 7, and can rotate around the bearing platform 1. A support part 3 is arranged at the top of the other end, and clamping members are installed on both sides of the support part 3. The clamping member includes a mounting seat 4. Holding arms 5 are provided on the opposite sides of the top end of the mounting seat 4. One end of the holding arm 5 is rotatably connected to the mounting seat 4, and the other end is installed with a jaw 6. The jaw 6 is a jaw with adjustable opening, and the jaw 6 is a pneumatic adaptive jaw, which adapts to the elastic deformation characteristics of workpieces to be measured with different materials (such as metals and composite materials), effectively avoids the problems of clamping overload or loosening, significantly improves the accuracy and stability of three-coordinate measurement, and meets the requirements of multi-face continuous measurement of complex workpieces.

[0021] Monitoring module: It includes a contour acquisition unit and a deformation acquisition unit 9. The contour acquisition unit is installed above the bearing platform 1 of the fixed module and is used to collect the contour data of the workpiece to be measured; the deformation acquisition unit 9 is arranged on the supporting surface of the fixed module (i.e., the top of the supporting part 3) and is responsible for obtaining the deformation data of the supporting surface of the fixed module when it contacts different surfaces of the workpiece to be measured.

[0022] Processing module: It is respectively connected to the contour acquisition unit and the deformation acquisition unit 9. The processing module calculates the theoretical geometric center of the workpiece to be measured by using the centroid method based on the contour data collected by the contour acquisition unit; at the same time, according to the deformation data obtained by the deformation acquisition unit 9, it calculates the dynamic geometric center when different surfaces of the workpiece to be measured contact the supporting surface. The processing module fuses the theoretical geometric center and the dynamic geometric center by the least square method. During the geometric center fusion process, it is assumed that the theoretical geometric center C 理论 and the dynamic geometric center C 动态 are both estimated values of the actual geometric center C 实际 but there are different error sources respectively. To optimize the fusion weights of the two, the least square method is used to construct an objective function to minimize the weighted sum of squared errors between the theoretical value and the dynamic value: ; where λ is the deformation weight factor, which reflects the confidence level of the dynamic data. The objective function is differentiated and set to zero to obtain the optimal solution: ; thus calculating the actual geometric center C 实际 . Among them C 理论 is the theoretical geometric center calculated by using the centroid method based on the contour data collected by the contour acquisition unit; C 动态 is the dynamic geometric center obtained by correcting the theoretical value through the deformation data. The final actual geometric center is the weighted fusion of the two; λ is determined according to the elastic deformation degree of the material of the supporting part. Through orthogonal experiments, it is found that the error is the smallest in the range of 0.2 - 0.8 for λ. This formula is based on the least square method principle. First, the dynamic geometric center is calculated through the deformation data, and then the theoretical geometric center and the dynamic geometric center are fused to obtain a geometric center that is more in line with the actual situation. When calculating the dynamic geometric center, first, according to the deformation amount Δdj of each deformation monitoring point, its weight w j is determined. The formula is w j = αΔd j (α The elastic coefficient of the material is calibrated by experiment, and the elastic modulus and Poisson's ratio of the support material are calibrated by experiment). Then the theoretical geometric center is corrected for deformation to obtain the dynamic geometric center: ; in, For deformation j The normal vector direction is perpendicular to the support surface and points to the workpiece, and is pre-calibrated by the support surface structure; n is the total number of deformation monitoring points; is the deformation variable of the jth monitoring point (scalar, unit: mm); It represents the vector correction of the deformation of all monitoring points to the theoretical geometric center, and the total offset is obtained by vector superposition.

[0023] Deformation Weight Factor λ Dynamic adjustment: Fixed value mode: When the workpiece material is known, λ It can be pre-calibrated to a fixed value (range: 0.2~0.8) through orthogonal test, for example, λ =0.5, composite material workpiece λ =0.7; Dynamic adaptive mode: If the device is equipped with a material recognition module (such as a spectral sensor), it can automatically match the material properties of the workpiece according to the real-time recognition. λ value, in order to take into account the deformation of the workpiece to be measured during the clamping process and realize the accurate calculation of the geometric center.

[0024] The control module connects the processing module and the fixing module, and drives the fixing module to make dynamic adjustments according to the coordinates of the actual geometric center calculated by the processing module. Specifically, it controls the electromagnetic ring 8 to be energized, so that the slip ring 7 drives the telescopic arm 2 to rotate and extend, adjusts the vertical height of the support part 3, controls the rotation angle of the arm 5 and the opening and closing of the clamp 6, and ensures that when different surfaces of the workpiece to be measured are in contact with the fixing module, the geometric center is always the actual geometric center.

[0025] This device fuses contour data and deformation data through the processing module, constructs a geometric center correction algorithm coupled with multiple physical fields, and accurately calculates the actual geometric center in real time. Based on the actual geometric center coordinates, the control module drives the telescopic arm 2, the support part 3, the arm 5 and the clamping jaw 6 to adjust in a coordinated manner, realizes closed-loop control of horizontal rotation, vertical lifting and clamping force, and dynamically compensates for the center offset caused by clamping deformation. The clamping jaw 6 is controlled by a pneumatic proportional valve, and the clamping force (range: 5N~200N) is dynamically adjusted according to the real-time deformation data fed back by the deformation acquisition unit to avoid the aggravation of the deformation of the workpiece to be measured due to excessive clamping force, and further improve the positioning accuracy of the geometric center.

[0026] It should be noted that: In the present application, the monitoring module is composed of a contour acquisition unit and a deformation acquisition unit. To obtain the three-dimensional point cloud data of the entire workpiece, and combine with the microscopic strain distribution of the support surface monitored by the deformation acquisition unit in real time. To achieve dynamic capture of contact mechanics parameters; the processing module is respectively connected to the contour acquisition unit and the deformation acquisition unit. Calculate the theoretical geometric center of the workpiece to be measured according to the contour data; then calculate the dynamic geometric center of the workpiece to be measured under different contact conditions based on the deformations of the force application points when the fixing module contacts different surfaces of the workpiece to be measured; finally, fuse the theoretical geometric center and the dynamic geometric center to determine the actual geometric center of the workpiece to be measured, and generate a reference with the authenticity of the geometric center of the workpiece to be measured. The control module is respectively connected to the processing module and the fixing module. According to the actual geometric center calculated by the processing module, dynamically adjust the fixing module (adjust the three-dimensional space coordinates), so that when any surface of the workpiece to be measured contacts the fixing module, its geometric center always remains the actual geometric center, thereby providing a stable and unified geometric center for the subsequent measurement of the coordinate measuring machine, realizing dynamic adjustment of the support point structure during the multi-posture clamping process of the workpiece, so that the actual geometric center of the workpiece to be measured remains spatially invariant with the measurement reference coordinate system; providing a dynamically stable metrology reference for multi-process measurement.

[0027] Embodiment: This embodiment will elaborate in detail on the specific situation of the coordinate measuring machine auxiliary alignment device in actual application, clearly showing the collaborative working process of each component in combination with the reference numerals in the drawings, so as to better understand the working principle and advantages of the device. The horizontal direction in this embodiment corresponds to the X / Y axis, and the vertical direction corresponds to the Z axis. As Figure 1 shown, in this embodiment, the contour acquisition unit and the deformation acquisition unit are respectively connected to the processing module, and the control module is respectively connected to the processing module, the telescopic arm, the support part, the holding arm, the clamping jaw and the electromagnetic ring; in this embodiment, the telescopic arm 2 selects an electric push rod type telescopic arm, because it has stable telescopic performance and high precision, and can meet the requirement of precise adjustment of the horizontal position of the workpiece. The clamping jaw 6 selects a pneumatic adaptive clamping jaw, which can automatically adjust the clamping force according to the shape and size of the workpiece to be measured, ensure the stability of clamping, and at the same time adapt to workpieces to be measured with different shapes. The support part 3 adopts a servo electric lifting column, which has high-precision vertical lifting control ability, can accurately adjust the height of the workpiece to be measured, and ensure its position accuracy in the vertical direction. The electromagnetic ring 8 adopts a segmented electromagnetic coil ring, which is composed of multiple independent coils arranged in a ring shape, and each coil can be energized independently. By controlling the current direction and intensity, a local magnetic field is generated, which interacts with the neodymium iron boron permanent magnet embedded in the slip ring 7 to realize precise movement control of the slip ring 7, and then accurately adjust the position of the telescopic arm 2. The contour acquisition unit adopts a laser displacement sensor; the deformation acquisition unit 9 adopts an integrated fiber Bragg grating (FBG) sensor; Before measurement, place the workpiece to be measured on the bearing platform 1 first: As Figures 2 - 5 shown, the bearing platform 1 is composed of a upper seat body 11 and a lower seat body 12 which are buckled. The centers of the opposite sides of the upper seat body 11 and the lower seat body 12 are respectively provided with a matching connecting boss 15 and a connecting groove. The connecting boss 15 is integrally formed with the lower seat body 12 and is inserted into the connecting groove of the upper seat body 11 to achieve preliminary positioning. At the same time, the groove wall 13 of the connecting groove is inserted into the depressions on both sides of the connecting boss for further positioning. Then, it is fixed by bolts to ensure the stable structure of the bearing platform 1.

[0028] In this embodiment, the three clamping mechanisms are radially distributed at 120°. Each clamping mechanism includes a telescopic arm 2, a support part 3 and a jaw 6. The telescopic arm is selected as an electric push rod type. An integrated fiber Bragg grating (FBG) sensor is embedded at the top of the mounting seat to monitor the deformation of the support part in real time.

[0029] One end of the telescopic arm 2 passes through the annular sliding groove 10 in sequence and extends into the annular cavity 14 to be connected with the slip ring 7. The electromagnetic ring 8 is controlled by the control module to be energized to generate a magnetic field, driving the slip ring 7 to move along the annular cavity, and then enabling the telescopic arm 2 to slide in the annular sliding groove 10 and rotate around the center of the seat body, and driving the telescopic arm 2 to expand and contract, so as to realize the adjustment of the positions of the support part 3 and the jaw 6 installed at the end of the telescopic arm 2 in two horizontal directions. The support part 3 is installed at the top of the end of the telescopic arm 2 facing away from the bearing platform 1, and is used to support the workpiece to be measured and can expand and contract in the vertical direction to realize the adjustment of the height of the workpiece to be measured. The jaw 6 is installed at one end of the holding arm 5 away from the mounting seat 4, and the holding arms 5 are located on the left and right sides of the mounting seat 4. The holding arms are connected to the mounting seat 4 through a driving motor and a rotating shaft. The opposite sides of the holding arms 5 and the mounting seat 4 are respectively connected by corresponding arc-shaped connecting ears. The openings of the arc-shaped connecting ears are arranged back to back, and the opposite sides are respectively connected to the holding arms 5 and the mounting seat 4, and the relative sides are connected by a rotating shaft. The driving motor is installed on the mounting seat 4, and the controller of the driving motor is connected to the control module. The driving motor is controlled by the control module to rotate, driving the holding arms 5 to rotate around the connection point, so that the contour formed by the holding arms 5 matches the contour of the workpiece to be measured, and the clamping position of the jaw 6 is adjusted. The jaw 6 adaptively clamps the workpiece to be measured under the action of the control module, making the jaw closely fit the surface of the workpiece to be measured to ensure the stability of clamping.

[0030] Data acquisition: The laser displacement sensor located above the bearing platform 1 starts to work, scans the workpiece to be measured placed on the bearing platform 1, and generates three-dimensional point cloud contour data. These data accurately record the external contour information of the workpiece to be measured, providing a key basis for calculating the theoretical geometric center in the follow-up.

[0031] The deformation acquisition unit 9 integrated with fiber Bragg grating (FBG) sensors is embedded at the top of the mounting base 4. When the workpiece to be measured is placed above the supporting part 3, due to factors such as the gravity of the workpiece to be measured, the supporting part 3 will produce different degrees of deformation. The deformation acquisition unit 9 monitors these deformation data in real time and transmits them to the processing module.

[0032] The processing module receives the three-dimensional point cloud contour data collected by the laser displacement sensor and the deformation data transmitted by the deformation acquisition unit 9. Based on the three-dimensional point cloud contour data, the theoretical geometric center of the workpiece to be measured is calculated. Specifically, when calculating, by analyzing and processing the coordinates of a large number of contour data points, the center of gravity position of the workpiece is determined, so as to obtain the theoretical geometric center; the dynamic geometric center is calculated according to the deformation data. The processing module first determines its weight according to the deformation amount of each deformation monitoring point Δd j The formula is: w j where w j = αΔd j ( α is the material elastic coefficient calibrated through experiments); then the deformation correction is performed on the theoretical geometric center to obtain the dynamic geometric center. The formula for the dynamic C 动态 is: ; where is the normal vector direction of the deformation j , which is pre-calibrated by the support surface structure, w j is the weight factor, Δd j is the deformation amount, The product of the three needs to determine the operation method according to the actual physical meaning, such as vector dot product or scalar weighting; Finally, the processing module weighted-fuses the theoretical geometric center and the dynamic geometric center by the least squares method to obtain the actual geometric center C 实际 The formula is: ; where λ is the deformation weight factor, and its value range is 0.2 ≤ λ ≤ 0.8, which can be calibrated through experiments. After each adjustment, the deformation data is re-collected and iteratively calculated until the difference between the actual geometric center coordinates calculated continuously twice is less than (in this embodiment ), the iteration is terminated.

[0033] The control module uses a PLC controller to receive the actual geometric center coordinates output by the processing module. Based on the actual geometric center coordinates, it controls the components of the electromagnetic ring 8, telescopic arm 2, clamping arm 5, gripper 6, and support part 3 to perform dynamic adjustments. Specifically: The control module sends instructions to the controller of the electromagnetic ring 8. The electromagnetic ring 8 consists of 16 groups of independent coils evenly distributed along the annular cavity, and each group of coils can be independently energized. When a specific coil is energized, the generated magnetic field interacts with the neodymium iron boron permanent magnet embedded in the slip ring 7, pushing the slip ring 7 to slide along the length direction of the electromagnetic ring 8. One end of the telescopic arm 2 passes through the annular chute 10 and is connected to the slip ring 7, thereby driving the telescopic arm 2 to slide in the annular chute 10 and rotate around the center of the seat body, adjusting the horizontal positions of the support part 3 and the gripper 6 to evenly distribute the clamping points and compensate for the horizontal center offset caused by the placement position of the workpiece to be measured or the deformation of the support part 3.

[0034] The support part 3 is a servo-electric lifting column, and its controller is connected to the control module. The control module drives the support part 3 to extend and retract in the vertical direction according to the actual geometric center coordinates, adjusts the height of the workpiece to be measured, and ensures that the vertical coordinates of the workpiece to be measured are consistent with the vertical coordinates of the actual geometric center, compensating for the center offset in the vertical direction.

[0035] Finally, subsequent measurements are carried out.

[0036] After the above dynamic adjustments, the geometric center of the workpiece to be measured is locked as the actual geometric center. At this time, the coordinate measuring machine performs high-precision measurement on the workpiece. During the measurement process, if the support part 3 deforms again due to slight movement of the workpiece or other factors, the deformation acquisition unit 9 will real-time monitor the new deformation data and transmit it to the processing module. The processing module recalculates the actual geometric center, and the control module drives the fixing module to make adjustments again according to the new actual geometric center coordinates, ensuring that the geometric center of the workpiece remains stable during the measurement process, thereby improving the accuracy and precision of the coordinate measurement.

Claims

1. Three-coordinate auxiliary alignment device, characterized in that, The device includes: A fixing module for dynamically clamping a workpiece to be measured; A monitoring module, including a contour acquisition unit and a deformation acquisition unit; the contour acquisition unit is placed above the bearing platform of the fixing module to obtain the contour data of the workpiece to be measured; the deformation acquisition unit is placed on the supporting surface of the fixing module to obtain the deformation data corresponding to different surfaces of the workpiece to be measured in contact with the supporting surface of the fixing module; A processing module, respectively connected to the contour acquisition unit and the deformation acquisition unit. The processing module calculates the theoretical geometric center of the workpiece to be measured according to the contour data, calculates the dynamic geometric center of the workpiece to be measured when different surfaces of the workpiece to be measured are in contact with the supporting surface according to the deformation data, and determines the actual geometric center of the workpiece to be measured by fusing the theoretical geometric center and the dynamic geometric center; A control module, connected to the processing module and the fixing module, drives the fixing module to perform dynamic adjustment according to the coordinates of the actual geometric center, so that when different surfaces of the workpiece to be measured are in contact with the fixing module, the geometric center is always the actual geometric center.

2. The three-coordinate auxiliary alignment device according to claim 1, wherein The processing module fuses the theoretical geometric center and the dynamic geometric center by the least squares method to obtain the actual geometric center. The specific formula is: ； Among them, λ is the deformation weight factor.

3. The three-coordinate auxiliary alignment device according to claim 1, characterized in that, The fixing module includes a bearing platform and at least three clamping mechanisms; The clamping mechanisms are respectively distributed radially along the circumferential side of the bearing platform to realize the support and clamping of different surfaces of the workpiece to be measured. The clamping mechanism includes a telescopic arm; One end of the telescopic arm is installed on the bearing platform and rotates along the bearing platform. A support part is arranged at the top of the other end of the telescopic arm. Clamping parts of the workpiece to be measured are respectively arranged on both sides of the end of the telescopic arm where the support part is arranged. The controller of the telescopic arm is connected to the control module; The clamping parts and the support parts are respectively installed on the telescopic arm, and through the telescopic of the telescopic arm and the rotation around the bearing platform, different support points and clamping points of the workpiece to be measured are formed, ensuring that the coordinates of the workpiece to be measured in the two horizontal directions are the same as the coordinates of the actual geometric center in the two horizontal directions.

4. The three-coordinate auxiliary alignment device according to claim 3, wherein, The clamping part includes a mounting seat; The mounting seat is installed at the top of the support part. Holding arms are respectively arranged on opposite sides of the mounting seat; One end of each holding arm is installed on both sides of the mounting seat and rotates along the connection part respectively. A clamping jaw is installed at the other end of each holding arm; The controller of the clamping jaw and the controller of the holding arm are respectively connected to the control module; The deformation acquisition unit is installed on the top of the mounting seat.

5. The three-coordinate auxiliary alignment device according to claim 4, characterized in that The clamping jaw is an adjustable-opening clamping jaw.

6. The three-coordinate auxiliary alignment device according to claim 4, characterized in that, The clamping jaw is a pneumatic self-adaptive clamping jaw to adapt to the surface of the workpiece to be measured.

7. The three-coordinate auxiliary alignment device according to claim 4, characterized in that, The holding arm is a telescopic holding arm, which elongates or shortens correspondingly according to the change of the angle between two adjacent telescopic arms to maintain the uniformity of the clamping points.

8. The three-coordinate auxiliary alignment device according to claim 3, characterized in that, The support part telescopically moves along the vertical direction of the telescopic arm to realize the adjustment of the workpiece to be measured in the vertical direction, ensuring that the coordinates of the workpiece to be measured in the vertical direction are the same as the vertical coordinates of the actual geometric center.

9. The three-coordinate auxiliary alignment device according to claim 3, wherein The bearing platform includes: a seat body; An annular cavity is arranged inside the seat body, and an annular sliding groove is arranged on the circumferential side of the seat body; An electromagnetic ring is arranged in the annular cavity, and a slip ring is arranged on the electromagnetic ring; The slip ring is sleeved outside the electromagnetic ring and slides along the length direction of the electromagnetic ring; The annular chute is communicated with the annular cavity; One end of the telescopic arm passes through the annular chute and is connected with the electromagnetic ring. The telescopic arm is slidably connected with the annular chute, and the telescopic arm moves on the electromagnetic ring through the slip ring to realize rotation around the center of the seat body; The controller of the electromagnetic ring is connected with the control module.

10. The three-coordinate auxiliary alignment device according to claim 9, characterized in that, The seat body includes an upper seat body and a lower seat body that are buckled together; Connection bosses and connection grooves that are adapted to each other are respectively arranged at the centers of the opposite sides of the upper seat body and the lower seat body, and upper annular chutes and lower annular chutes are respectively arranged on the opposite peripheral sides of the upper seat body and the lower seat body; Upper annular cavities and lower annular cavities with opposite openings are respectively arranged on the peripheral sides of the connection boss and the connection groove. The cross sections of the upper annular cavity and the lower annular cavity are semicircular. The upper annular cavity and the lower annular cavity are respectively located between the upper annular chute and the connection boss, and between the lower annular chute and the connection groove. The upper annular cavity and the lower annular cavity are respectively communicated with the upper annular chute and the lower annular chute; The upper annular chute and the lower annular chute form an annular chute; The top and bottom of the end of the telescopic arm facing the seat body are respectively slidably connected with the upper annular chute and the lower annular chute.

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