Non-contact blade full feature measuring device and measuring method

Abstract

This invention belongs to the field of measuring devices and specifically discloses a non-contact blade full-feature measuring device and method. It includes a measuring device base; a three-dimensional motion module mounted on the measuring device base; a rotational motion module including a linear laser calibration component; a linear laser measurement module including a blade edge line laser group and a blade body line laser; and a control module for controlling the movement of the three-dimensional motion module, so that the blade under test and the linear laser calibration component enter the working range of the linear laser measurement module. Simultaneously, based on the information of the linear laser calibration component obtained by the linear laser measurement module, the transformation relationship between the linear laser coordinate system and the blade coordinate system is determined. Based on the information of the blade under test obtained by the linear laser measurement module, the transformation relationship, and the blade theoretical model, the machining allowance of the blade under test is determined. This invention enables non-contact in-situ measurement and features comprehensive measurement points, high measurement accuracy, and high speed.

Description

Technical Field

[0001] This invention belongs to the field of measuring devices, and more specifically, relates to a non-contact blade full-feature measuring device and measuring method. Background Technology

[0002] Blades are among the most critical components of aero-engines, and their surface quality directly determines the engine's service life and performance. Aero-engine blades have very small and unevenly distributed machining allowances, and stringent machining quality requirements. The small edge radii, large overall blade twist, and complex profile make blade measurement challenging. Currently, the commonly used measurement method is contact measurement—using a coordinate measuring machine to take measurements at specific points on the blade. However, this method suffers from slow measurement speed, complex procedures, and difficulty in measuring the small edge radii. This has become a key weakness and limitation restricting the efficient and high-precision grinding of aero-engine blades, hindering the further development of high-precision manufacturing of aero-engine blades.

[0003] To address the aforementioned issues, patent document CN105180834A discloses a three-dimensional non-contact measurement device for the inlet and outlet edges of a blade. This device employs two three-dimensional laser contour scanners to scan the contours on both sides of the blade. It can scan the contours on both sides of the inlet and outlet edges with a wide range, complete coverage, and high precision, thereby obtaining the shape of the inlet and outlet edges of the blade. This solves the problem that existing technologies cannot perform high-precision three-dimensional non-contact measurement of the inlet and outlet edges.

[0004] However, the three-dimensional non-contact measuring device for the inlet and outlet edges of blades disclosed in patent document CN105180834A can only perform three-dimensional non-contact measurements on the inlet and outlet edges of blades, which limits the measurement range. It cannot measure the blade base and blade back, and cannot achieve full feature measurement of the blade. On the other hand, the three-dimensional non-contact measuring device for the inlet and outlet edges of blades disclosed in patent document CN105180834A can only measure the contour of the inlet and outlet edges, and cannot quantitatively measure the machining allowance of the machined contour, and cannot achieve the allowance measurement of the contact measurement method. Summary of the Invention

[0005] To address the aforementioned deficiencies or improvement needs of existing technologies, this invention provides a non-contact blade full-feature measurement device and method. Combining the characteristics of the blade under test with the features of linear laser measurement technology, a non-contact in-situ measurement device using multi-line laser standard components is designed. The structure and specific configuration of key components such as the motion module, calibration module, and multi-line laser measurement module are studied and designed. This effectively solves the problems of low accuracy, cumbersome operation, and inability to quantitatively measure the machining allowance of the processed contour in existing contact measurements. Simultaneously, it can measure all features of small and medium-sized blades, including the inlet and outlet edges (blade margins) and the blade body (blade base and blade back). It achieves the stitching of point cloud data collected by the line laser emitter in the blade's theoretical model coordinate system, enabling in-situ measurement with high accuracy and fast detection speed.

[0006] To achieve the above objectives, according to one aspect of the present invention, a non-contact blade full-feature measurement device is provided, comprising:

[0007] Measuring device base;

[0008] A three-dimensional motion module, mounted on the base of the measuring device, is used to mount the blade to be measured for three-dimensional motion.

[0009] A rotary motion module, mounted on the three-dimensional motion module, is used to drive the rotation of the blade under test. The rotary motion module includes a linear laser calibration component.

[0010] A linear laser measurement module is mounted on the base of the measuring device. This linear laser measurement module includes a leaf edge laser group and a leaf body laser group.

[0011] The control module controls the movement of the three-dimensional motion module, enabling the blade under test and the linear laser calibration component to enter the working range of the linear laser measurement module. Simultaneously, based on the information of the linear laser calibration component obtained by the linear laser measurement module, the transformation relationship between the linear laser coordinate system and the blade coordinate system is determined. Based on the information of the blade under test obtained by the linear laser measurement module, the transformation relationship, and the blade theoretical model, the machining allowance of the blade under test is determined.

[0012] As a further preferred embodiment, the leaf edge laser group includes at least two first lasers arranged along the central axis of the rotating motion module;

[0013] The blade-line laser includes a set of second lasers arranged perpendicularly to the first laser;

[0014] The linear laser calibration assembly includes a leaf stalk, a calibration ball mounting base, and a leaf basin / leaf back calibration ball group and a leaf edge calibration ball group disposed on the calibration ball mounting base. The leaf basin / leaf back calibration ball group is disposed on the top surface of the calibration ball mounting base, and the leaf edge calibration ball group is disposed on any side of the axial side of the calibration ball mounting base.

[0015] As a further preferred embodiment, the linear laser measurement module further includes a first linear laser mounting frame, a second linear laser mounting frame, and a two-dimensional translation stage. The first linear laser mounting frame is used to mount the first laser, and the two-dimensional translation stage is disposed on the second linear laser mounting frame and is used to mount the second laser.

[0016] As a further preferred embodiment, the three-dimensional motion module includes a Y-axis motion unit disposed on the base, an X-axis motion unit disposed on the Y-axis motion unit, and a Z-axis motion unit disposed on the X-axis motion unit, wherein the Y-axis motion unit, the X-axis motion unit, and the Z-axis motion unit are arranged perpendicularly to each other.

[0017] As a further preferred embodiment, the measuring device also includes a six-degree-of-freedom robot, the end of which is equipped with a blade gripper;

[0018] The measuring device also includes a measuring cover, which is mounted on the base of the measuring device and provides a sealed working space for the three-dimensional motion module, the rotational motion module, and the linear laser measuring module.

[0019] As a further preferred embodiment, the control module is connected to the three-dimensional motion module, the linear laser measurement module, and the six-degree-of-freedom robot via a fieldbus. The control module includes a data acquisition board, which is used to acquire information from the motor photoelectric encoders of the three-dimensional motion module and the linear laser measurement module.

[0020] According to another aspect of the present invention, a non-contact method for measuring the full characteristics of a blade is also provided, comprising the following steps:

[0021] The control module constructs a theoretical model of the blade, divides the blade into measurement areas based on the theoretical model and the characteristics of linear laser measurement, and determines the measurement motion paths of the linear laser measurement module, the three-dimensional motion module, and the rotational motion module based on the divided measurement areas.

[0022] The linear laser measurement module, the three-dimensional motion module, and the rotational motion module are coordinated to move according to the measurement path, so as to measure the blade according to the measurement area and obtain the complete point cloud of the cross-sectional surface of the blade under test.

[0023] Based on the position coordinate transformation relationship, the complete point cloud of the cross-sectional surface of the blade to be measured is transformed into the blade coordinate system, and the machining allowance is determined based on the blade theoretical model and the point cloud transformed into the blade coordinate system.

[0024] As a further preferred embodiment, the step of dividing the blade into measurement regions based on the blade theoretical model and line laser measurement characteristics includes:

[0025] The blade measurement area is divided according to the line laser measurement range, measurement curvature, and shape characteristics of the cross-sectional surface of the blade theoretical model. The measurement area includes: the blade base, the blade back, the left blade edge, and the right blade edge.

[0026] As a further preferred embodiment, the system also includes fabricating a linear laser calibration assembly based on the specifications of the blade to be tested, the blade's theoretical model, and the characteristics of line laser measurement. This assembly includes:

[0027] The specifications of the petiole of the linear laser calibration component are obtained based on the specifications of the petiole of the blade to be tested.

[0028] Based on the measurement range of the line laser emitter corresponding to the leaf basin and leaf back parts of the blade, determine the installation position of the leaf basin and leaf back calibration ball group on the linear laser calibration assembly;

[0029] Based on the measurement range of the line laser emitter of the line laser group measuring the left and right leaf edges, determine the installation position of the leaf edge calibration ball group on the linear laser calibration assembly.

[0030] As a further preferred embodiment, after the linear laser calibration component is manufactured, the linear laser calibration component is measured based on the position information of the three-dimensional motion module and the rotational motion module mounted on the blade under test, as well as the characteristics of the line laser measurement, to determine the transformation relationship between the line laser coordinate system and the blade coordinate system. Specifically:

[0031] The linear laser calibration component is measured according to the line laser measurement procedure to obtain the first point set;

[0032] The position information of the three-dimensional motion module and the rotational motion module are used to measure the linear laser calibration component to obtain the second point set;

[0033] The transformation relationship between the linear laser coordinate system and the blade coordinate system is determined based on the first and second point sets:

[0034] Subtract the center point from each point in the first set of points and the second set of points respectively to obtain the first set of center points and the second set of center points.

[0035] The covariance matrix is ​​determined based on the first and second center point sets, and the rotation and translation matrices are obtained based on singular value decomposition.

[0036] In summary, compared with the prior art, the above-described technical solutions conceived by this invention mainly possess the following technical advantages:

[0037] 1. This invention studies and designs the structure and specific configuration of its key components, such as the motion module, calibration module, and multilinear laser measurement module. Correspondingly, it can effectively solve the problems of low accuracy, cumbersome operation, and inability to quantitatively measure the machining allowance of the processed contour in existing contact measurements. At the same time, it can measure all features of small and medium-sized blades, including the inlet and outlet edges of the blade, i.e., the blade edge, and the blade body, i.e., the blade base and blade back. It realizes the stitching of point cloud data collected by the line laser emitter in the coordinate system of the blade theoretical model, and can realize in-situ measurement. It has the characteristics of high measurement accuracy and fast detection speed.

[0038] 2. This invention achieves full-feature non-contact measurement through two sets (three in total) of line laser measuring instruments, which can measure all features of small and medium-sized blades, including the air intake and exhaust edges of the blade, i.e., the leaf margin, and the leaf body, i.e., the leaf base and leaf back.

[0039] 3. The main cost of this invention lies in the line laser measuring instrument. Compared to the current coordinate measuring machine (CMM) method that can meet the inspection requirements of small and medium-sized blades, it has a significant cost advantage, costing only one-tenth of the CMM.

[0040] 4. This invention employs an optical detection method, which, compared to traditional contact measurement, significantly improves detection speed and optimizes the detection process, laying the foundation for integrated processing and detection. Furthermore, it overcomes the difficulty of sampling points at the inlet and outlet edges in contact measurement methods, greatly improving the density and accuracy of leaf edge detection.

[0041] 5. This invention establishes a three-axis platform that can perform characteristic detection based on different types of blades, realizing non-contact detection of all blade features.

[0042] 6. The entire measurement stage of this invention is driven by high-precision linear guides, which can ensure the accuracy of the motion and overcome the shortcomings of low motion accuracy of robots.

[0043] 7. This invention achieves in-situ multi-line laser measurement of small and medium-sized blades by using standard parts designed based on the theoretical model of the blades to be measured. This solves the problem that the accuracy of data stitching from multiple line laser devices cannot meet the requirements of high-precision measurement, and overcomes the poor performance of commonly used data processing methods such as point cloud matching on highly complex curved surfaces. It can meet the measurement needs of complex parts such as blades. Simultaneously, by using the calibration ball of the standard parts for positioning, the point cloud data collected by the line laser emitter is stitched together in the coordinate system of the blade's theoretical model, taking a significant step from measuring the contour to measuring the machining allowance, enabling in-situ measurement. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of the structure of a non-contact blade full feature measurement device according to an embodiment of the present invention;

[0045] Figure 2 This is another structural schematic diagram of a non-contact blade full feature measurement device according to an embodiment of the present invention;

[0046] Figure 3 This is a schematic diagram of the structure of the blade to be tested according to an embodiment of the present invention;

[0047] Figure 4 This is a schematic diagram of the structure of the linear laser calibration component involved in an embodiment of the present invention.

[0048] In all the accompanying drawings, the same reference numerals denote the same technical features, specifically: base-1, six-DOF robot-2, measuring housing-3, measuring display-4, command input device-5, electrical control box-6, measuring device base-7, X-axis guide rail-8, X-axis slide table-9, X-axis linear guide rail-10, X-axis ball screw mechanism-11, X-axis servo motor-12, Y-axis linear guide rail-13, Y-axis ball screw mechanism-14, Y-axis servo motor-15, Z-axis linear guide rail. -16, Z-axis servo motor -17, electric rotary slide -18, blade pneumatic clamping device -19, blade to be tested -20, blade edge laser assembly -21, blade body laser assembly -22, two-dimensional translation stage -23, laser assembly beam -24, left blade edge -25, right blade edge -26, blade body basin -27, blade body back -28, petiole -29, calibration ball mounting base -30, blade basin and back calibration ball assembly -31, blade edge calibration ball assembly -32. Detailed Implementation

[0049] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0050] like Figures 1 to 4As shown in the figure, an embodiment of the present invention provides a non-contact blade full-feature measurement device, comprising: a measurement device base 7; a three-dimensional motion module disposed on the measurement device base 7 for carrying the blade to be measured for three-dimensional motion; a rotational motion module disposed on the three-dimensional motion module for driving the blade to be measured to rotate, the rotational motion module including a linear laser calibration component; a linear laser measurement module disposed on the measurement device base 7, the linear laser measurement module including a blade edge line laser group 21 and a blade body line laser 22; and a control module, the control module being used to control the motion of the three-dimensional motion module so that the blade to be measured and the linear laser calibration component enter the working range of the linear laser measurement module. At the same time, based on the linear laser calibration component information obtained by the linear laser measurement module, the transformation relationship between the linear laser coordinate system and the blade coordinate system is determined. Based on the blade information obtained by the linear laser measurement module, the transformation relationship, and the blade theoretical model, the machining allowance of the blade to be measured is determined.

[0051] More specifically, the system mainly includes a base 1, a six-degree-of-freedom robot 2, a line laser blade full-feature measurement device 3, a measurement display 4, a command input device 5, and an electrical control box 6. The base 1 houses the line laser blade full-feature measurement device 3, the measurement display 4, the command input device 5, and the electrical control box 6. The six-degree-of-freedom robot 2 is used to clamp and transport blades to the blade clamping point of the blade full-feature measurement mechanism for loading and unloading the blades to be tested. The measurement housing 3 is placed on the base 1 and integrates a mechanism for fully automatic non-contact full-feature measurement of the blades to be tested. The measurement display 4 outputs and displays the point cloud results measured by the line laser blade full-feature measurement device, and, with the cooperation of the command input device 5, can input control signals to switch to manual measurement mode. The electrical control box 6 mainly houses the system control host, as well as the controllers for the motor drivers and the laser emitter.

[0052] like Figure 2The measuring device integrated inside the measuring housing 3 includes a measuring device base 7, an X-axis guide rail 8, an X-axis slide 9, an X-axis linear guide rail 10, an X-axis ball screw mechanism 11, an X-axis servo motor 12, a Y-axis linear guide rail 13, a Y-axis ball screw mechanism 14, a Y-axis servo motor 15, a Z-axis linear guide rail 16, a Z-axis servo motor 17, an electric rotary slide 18, a blade pneumatic clamping device 19, the blade to be measured 20, a blade edge line laser group 21, a blade body line laser 22, an overall two-dimensional translation stage 23, and a line laser mounting beam 24. The measuring device base 7 serves as the foundation for the entire device, used for fixing and supporting the entire system. The X-axis slide 9 is placed on the X-axis guide rail 8, supporting the X-axis linear guide rail 10. The X-axis servo motor 12 drives the X-axis ball screw mechanism 11, providing movement in the X direction for the entire measuring device. The Y-axis servo motor 15, Y-axis ball screw mechanism 14, and Y-axis linear guide rail 13 provide movement in the Y direction for the entire measuring device. The Z-axis servo motor 17, Z-axis ball screw mechanism, and Z-axis linear guide rail 16 provide movement in the Y direction for the entire measuring device. The blade clamping mechanism is fixed on the Z-axis linear guide rail 16 and consists of an electric rotary slide 18, a pneumatic blade clamping device 19, and the blade to be measured 20. The electric rotary slide 18 provides 360° rotation for the blade to be measured 20, while the pneumatic blade clamping device clamps the blade using air pressure, ensuring repeatability and positioning accuracy for multiple clamping operations. The blade edge line laser assembly 21 consists of two line laser emitters used to measure the left and right edge portions of the blade 20 under test. The lenses of the two line laser emitters are perpendicular to each other, ensuring that the line laser stripes emitted by the two emitters are on the same plane. The assembly is mounted on the line laser mounting beam 24. The blade body line laser 22 is mounted on an integrated two-dimensional translation stage 23, forming the assembly mounted on the line laser mounting beam 24. The integrated two-dimensional translation stage 23 provides micro-adjustments in the X and Z directions for the blade body line laser 22, ensuring that the laser beams of the blade body line laser and the blade edge line laser are on the same plane. The line laser emitters selected in this device can measure the X and Y axis signals of a single cross-sectional profile. This line laser blade full-feature measurement device can ensure the measurement of the entire feature area of ​​the blade in an optical non-contact manner. While improving measurement speed, it also ensures measurement accuracy, laying the foundation for integrated machining and measurement. It solves the problem that commonly used contact measurements cannot quickly and efficiently measure the blade edge, and it also solves the problem that existing non-contact measurements cannot completely measure the full features of the blade.

[0053] like Figure 3 The diagram shows the structure of the leaf measured by this invention. In the diagram, 25 represents the left leaf margin, 26 represents the right leaf margin, 27 represents the leaf base portion of the leaf blade, and 28 represents the back portion of the leaf blade.

[0054] The entire system requires ensuring the stability of the base and the six-DOF robot installation, as well as the installation stability of the base and pedestal of the line laser blade full feature measurement device. This guarantees the stable motion of the three-axis linear guide rails and the stable operation of the line laser emitter within the device. During the measurement process, the synchronization of the three-axis servo motors, robot arm, photoelectric encoder, and line laser emitter must be ensured, guaranteeing synchronization during both the measurement and data acquisition processes. In the installation of the line laser emitter, it is crucial to ensure that the beams of the two edge line laser emitters in the blade edge measurement group remain perpendicular and on the same plane, and that the beams of the blade body line laser emitter and the edge line laser emitter are also on the same plane.

[0055] The electrical control process of the entire non-contact blade full-feature measurement device is as follows: A six-degree-of-freedom robot, consisting of a robot arm and a robot controller, is connected to the robot controller and the non-contact line laser blade full-feature measurement device via a fieldbus from the system host. Information from the linear guide servo motor and photoelectric encoder is acquired through the system host's data acquisition board. The system controller sends the robot arm's planned travel route data, based on the site conditions, to the robot controller. The robot arm executes the operation according to the planned route, completing the transport of the blade to be measured to the non-contact blade full-feature measurement device. The system controller sends a three-axis linear guide motion signal, planned according to the blade characteristics, to the non-contact blade full-feature measurement device. The servo motor motion controller receives the signal and drives the ball screw mechanism to move the linear guide. Through XYZ three-axis linkage, the blade can move in three directions. The system controller also sends an electric rotary slide motion signal, planned according to the blade characteristics, to the non-contact blade full-feature measurement device. The electric slide motion controller receives the signal and moves the motor according to the planned signal. The system control host synchronously acquires the contour data and photoelectric encoder signals obtained by the leaf edge laser group and the leaf body laser measurement device, and classifies and summarizes the corresponding signals to obtain the leaf edge and leaf body measurement data at different heights and angles of the blade under test. The measured data point cloud is then stitched together to finally obtain the full feature measurement data of the blade.

[0056] In one embodiment of the present invention, a line laser measurement method for determining a blade based on a defined measurement region includes the following steps:

[0057] Step 1: The control module constructs a theoretical model of the blade, divides the blade into measurement areas based on the theoretical model and the characteristics of line laser measurement, and determines the measurement motion paths of the linear laser measurement module, the three-dimensional motion module, and the rotational motion module based on the divided measurement areas.

[0058] Specifically, the blade is divided into measurement areas based on the blade's theoretical model and the characteristics of line laser measurement, including:

[0059] The blade measurement area is divided according to the line laser measurement range, measurement curvature, and shape characteristics of the cross-sectional surface of the blade theoretical model. The measurement area includes: the blade base, the blade back, the left blade edge, and the right blade edge.

[0060] Because high-precision line laser emitters have a relatively small measurement range and are not very effective at measuring sharp edges, they are suitable for measuring surfaces with relatively gentle curvature. Therefore, a single line laser emitter cannot completely measure the entire blade profile in a single measurement; multiple line laser emitters are often required to perform combined measurements to achieve a complete scan of the blade profile. The first step is to divide the measurement area... Figure 1 The shape characteristics of the blade cross-section at a certain Z-coordinate are analyzed. The blade back and blade base sections have relatively gentle overall shapes and small curvatures; the right and left blade edges have relatively sharp overall shapes and small rounded corners. Based on the characteristics of the line laser measurement range, the curvature measurement, and the shape characteristics of the blade cross-section to be measured, the blade is divided into multiple measurement areas: blade base, blade back, left blade edge, and right blade edge.

[0061] Step two: Based on the specifications of the blade to be tested, the blade's theoretical model, and the characteristics of line laser measurement, fabricate a linear laser calibration assembly. For example... Figure 1 As shown, in this step, the linear laser calibration assembly includes a petiole 29, a calibration ball mounting base 30, a set of calibration balls on the leaf base and back 31, and a set of calibration balls on the leaf margin 32. To fabricate the linear laser calibration assembly, its parameters must first be determined. To ensure that the linear laser calibration assembly and the leaf under test are under the same clamping conditions, the specifications of the petiole of the linear laser calibration assembly are consistent with those of the petiole of the leaf under test; the overall dimensions of the calibration ball mounting section between standards are consistent with those of the leaf under test, and the method for determining the mounting positions of each calibration ball is as follows:

[0062] Based on the measurement range of the line laser emitter 6 corresponding to the leaf base and leaf back of the blade, the installation position of the leaf base and leaf back calibration ball group on the linear laser calibration assembly is determined, ensuring that the installation position of the leaf base and leaf back calibration ball group is within the measurement range of the leaf blade line laser 22. Based on the measurement range of the line laser emitter of the leaf edge line laser group 21 measuring the left and right leaf edges of the blade, the installation position of the leaf edge calibration ball group on the linear laser calibration assembly is determined, ensuring that the installation range of the leaf edge calibration ball group is within the measurement range of the line laser emitter of the leaf edge line laser group 21. The final linear laser calibration assembly has the same petiole parameters as the blade under test, allowing the linear laser calibration assembly and the blade under test to be under the same clamping conditions; the three calibration balls of the leaf base and leaf back calibration ball group can be completely scanned by the laser emitted by the leaf blade line laser 22 in one go, and the three calibration balls of the leaf edge calibration ball group can be completely scanned by the laser emitted by the line laser emitter of the leaf edge line laser group 21 in one go.

[0063] Based on the motion information from the 3D motion module and the rotational motion module, as well as the characteristics of line laser measurement, the linear laser calibration component is measured to determine the transformation relationship between the line laser coordinate system and the blade coordinate system. Specifically,

[0064] The X-axis guide rail 8, X-axis slide 9, X-axis linear guide rail 10, X-axis ball screw mechanism 11, X-axis servo motor 12, Y-axis linear guide rail 13, Y-axis ball screw mechanism 14, Y-axis servo motor 15, Z-axis linear guide rail 16, and Z-axis servo motor 17 are mounted on the base 7 with measuring device, ensuring installation stability and smooth movement of the linear guide rails on all three axes. The electric rotary slide 18 is fixedly connected to the pneumatic blade clamping device 19, and the whole assembly is mounted on the Z-axis linear guide rail 16, ensuring that the pneumatic blade clamping device 19 can follow the three-axis linear guide rails and the electric slide to achieve movement in three directions. A 360° rotation is performed; the blade edge laser assembly 21, blade body laser 22, and the overall 2D platform 23 are mounted on the laser mounting beam 24, ensuring that the two laser emitters of the blade edge laser assembly 21 are vertically positioned and that the beams emitted by the two laser emitters are coplanar with a significant overlap in the measurement area. The beams emitted by the blade body laser 22 and the blade edge laser assembly 21 are also ensured to be coplanar, and the blade body laser 22 and the blade edge laser assembly 21 are separated by a distance of more than two blade widths, ensuring that the beams emitted by the relevant laser emitters do not interfere with each other when measuring the blade edge and blade body. Assemble the entire device: assemble the six-degree-of-freedom robot 2, the blade full-feature measurement device 3, the measurement display 4, the command input device 5, and the electrical control box 6 into the designated positions, ensuring installation stability and preventing path conflicts between the various devices. Wiring Connections: Connect the system control host to the three-axis servo motor drivers, robot controller, electric rotary slide controller, blade edge and blade line laser controllers, measurement display, and command input device to ensure data transmission synchronization. Complete the overall calibration of blade edge line laser group 21 and blade line laser 22.

[0065] More specifically, when the blade under test is adjusted to the designated measurement position, the linear laser calibration component can be calibrated and measured based on the motion information of the three-dimensional motion module and the rotational motion module, or it can be measured directly by setting a coordinate measuring machine. For example, the linear laser calibration component is measured according to the line laser measurement procedure to obtain the first point set. Specifically, the calibration ball groups of the leaf base and leaf back and the leaf edge of the linear laser calibration component are measured separately using a line laser emitter to obtain the calibration ball contour coordinates of the leaf base and leaf back and the leaf edge calibration ball groups; the center of the ball is fitted based on the calibration ball contour coordinates of the leaf base and leaf back and the leaf edge calibration ball groups to obtain the center coordinates of the leaf base and leaf back and the leaf edge calibration ball groups, and the first point set is obtained by combining them.

[0066] Specifically, during the measurement of the linear laser calibration component, the linear laser calibration component is clamped in the same way as the blade to be tested. A line laser emitter is used to measure the calibration ball group on the leaf base and back of the linear laser calibration component, obtaining the XY coordinates of the calibration ball contour. The XY coordinates of the ball are then fitted to the center of the ball using the measured circular contour XY coordinates to obtain the XY coordinates of the center of the calibration ball group 10. Similarly, a line laser group is used to measure the calibration ball group on the leaf edge of the linear laser calibration component, obtaining the XY coordinates of the calibration ball contour. The XY coordinates of the ball are then fitted to the center of the ball using the measured circular contour XY coordinates to obtain the XY coordinates of the center of the ball. Finally, the XY coordinates of the centers of the three calibration balls in the leaf base and back calibration ball group under the measurement coordinate system of the linear laser are obtained, forming point set A. Similarly, the XY coordinates of the centers of the three calibration balls in the leaf edge calibration ball group under the measurement coordinate system of the linear laser are obtained, forming point set B. Point set A and point set B constitute the first point set.

[0067] Methods for determining the center of a circle by fitting the circle equation to the measured center profile include:

[0068] According to the equation of a circle x 2 +y 2 +ax+by+c=0 yields

[0069]

[0070] Where a, b, and c are the unknowns to be solved;

[0071] Based on the XY coordinates of the circular contours measured in the online laser coordinate system using the calibration ball group 10 on the leaf base and the calibration ball group 11 on the leaf margin, the resulting equations can be written in matrix form:

[0072]

[0073] Where x1, ..., x n Let y1, ..., y2 be the X-axis coordinates of the circular outline. n The y-axis coordinate of the circular outline.

[0074] The above equation is in the form AX = b, in which...

[0075]

[0076] The solution yields:

[0077]

[0078] After obtaining a, b, and c, the fitting equation for the circular profile is obtained. Then, the point set A and B, composed of the XY coordinates of the center of the calibration ball group 10 on the leaf basin and the calibration ball group 11 on the leaf edge, are obtained in the online laser measurement coordinate system.

[0079]

[0080] Where, x a1 x a2 x a3 y a1 y a2 y a3 The three leaf basin and leaf back calibration center XY axis coordinates are obtained from line laser measurement; x b1 x b2 x b3 y b1 y b2 y b3 The three leaf edge calibration center XY axis coordinates are obtained from line laser measurement.

[0081] The linear laser calibration component is measured using a coordinate measuring machine (CMM) to obtain a second point set. The petiole portion of the linear laser calibration component is measured using a CMM to determine key petiole points. A blade coordinate system is established based on the key petiole points. The calibration ball groups on the leaf base and leaf back of the linear laser calibration component and the calibration ball groups on the leaf margin are measured using a CMM to obtain a three-dimensional point set in the blade coordinate system. The second point set is obtained based on the dimensions of the first point set and the three-dimensional point set.

[0082] First, the petiole portion of the linear laser calibration assembly is measured using a coordinate measuring machine (CMM). Based on the measured coordinates of key points on the petiole, a measurement coordinate system consistent with the coordinate system of the theoretical blade model (i.e., the blade coordinate system) is established. In the blade coordinate system, the CMM is used to measure the calibration sphere group 10 on the leaf base and leaf back, and the calibration sphere group 11 on the leaf edge, respectively, obtaining the XYZ coordinates of the sphere centers. To ensure consistency with the data dimensions of the first point set, the Z coordinates of the calibration sphere groups measured by the CMM are discarded. Finally, the set of center points C for the calibration spheres on the leaf base and leaf back, and the set of center points D for the calibration spheres on the leaf edge, are obtained in the blade coordinate system; this is the second point set.

[0083]

[0084] Where, x c1 x c2 x c3 y c1 y c2 y c3 The X and Y axis coordinates of the calibration center of the three leaf basins and leaf backs, respectively, were measured by a coordinate measuring machine; d1 x d2 x d3 y d1 y d2 y d3 These are the XY axis coordinates of the three leaf edge calibration centers measured by a coordinate measuring machine.

[0085] The transformation relationship between the linear laser coordinate system and the blade coordinate system is determined based on the first and second point sets.

[0086] Subtract the center point from each point in the first set of points and the second set of points respectively to obtain the first set of center points and the second set of center points.

[0087] The covariance matrix is ​​determined based on the first and second center point sets, and the rotation and translation matrices are obtained based on singular value decomposition.

[0088] Taking the point set A in the online laser coordinate system and the point set C in the blade coordinate system measured by a coordinate measuring machine of the blade base and blade back calibration ball group 10 of the linear laser calibration component as examples, point set C and point set A satisfy:

[0089] C = R·A + T

[0090] Where R is the rotation matrix between the line laser coordinate system and the blade coordinate system, and T is the translation matrix between the line laser coordinate system and the blade coordinate system;

[0091] The center points of point set A and point set C are:

[0092]

[0093] Where centroidA is the center point of point set A. Let x and y be the X and Y coordinates of the center point, respectively. Let centroidB be the center point of point set C. These are the X and Y coordinates of the center point, respectively.

[0094] Subtract the center point centroidA from each point in point set A, and subtract the center point centroidB from each point in point set C. This yields point set A1, where the center of point set A is moved to the origin, and point set C1, where the center of point set C is moved to the origin.

[0095]

[0096] Determine the covariance matrix H of the two point sets A1 and C1 that have been moved to the origin, and use singular value decomposition (SVD):

[0097] H = A1·C1 T

[0098] [U,S,V]=SVD(H)

[0099] Where H is the covariance matrix, C1 TLet [U,S,V] be the transpose of the point set C1, and let [U,S,V] be the result of SVD decomposition of the covariance matrix H, where U is an orthogonal matrix, S is a diagonal matrix, and V is the transpose of the orthogonal matrix.

[0100] Finally, the rotation matrix T and the translation matrix R can be obtained.

[0101]

[0102] Among them, VU T It is the transpose of the orthogonal matrix U.

[0103] By using a line laser to measure the linear laser calibration component to obtain the first point set, and then using a coordinate measuring machine to measure the linear laser calibration component to obtain the second point set, the transformation relationship can be obtained to achieve accurate stitching of point cloud data of various parts of the blade under test. This solves the problem that the accuracy of stitching data collected by multiple line laser devices cannot meet the high-precision measurement requirements of aircraft blades, and overcomes the obstacle that commonly used data processing methods such as point cloud matching are not effective on highly complex curved surfaces.

[0104] Step 3: Based on the measurement motion path, the linear laser measurement module, the 3D motion module, and the rotational motion module are controlled to move collaboratively to measure the blade according to the measurement area, thereby obtaining a complete point cloud of the cross-sectional surface of the blade under test. Specifically:

[0105] Controlled by the system host, the six-degree-of-freedom robot 2 receives corresponding attitude signals. The end effector of the six-degree-of-freedom robot 2, holding the blade under test 20, moves to the blade full-feature measurement device 3. The blade pneumatic clamping device 19 of the blade full-feature measurement device 3 moves to the side closest to the six-degree-of-freedom robot 2 via a three-axis linear guide. The six-degree-of-freedom robot then installs the blade under test, and the blade pneumatic clamping device 19 clamps and fixes the blade 20. The system host controls the servo motor drivers of the XYZ axis linear guides, which drive the ball screw mechanism, moving the blade pneumatic clamping device 19 and the blade 20 to a position where the blade 20's Z-axis zero point is coplanar with the beams of the blade edge laser group 21 and the blade body laser 22. At this point, the Z-axis servo motor is locked, and the system host sends a signal to the X-axis servo motor 12 and the Y-axis servo motor 15, which then drive the X-axis ball screw mechanism 11 and the four Y-axis ball mechanisms 14, ultimately moving the blade 20 in the XY plane.

[0106] In this invention, with the Z-axis fixed, the profile signals of the blades on the X and Y axes are acquired.

[0107] (1) Measuring the left edge 25 of the blade: With the Z-axis servo motor locked, the X-axis servo motor 12 and the Y-axis servo motor 15 can drive the X-axis ball screw mechanism 11 and the four mechanisms 14 of the Y-axis ball screw to move the blade 20 under test in the XY plane. The system control host sends control signals to the XY-axis servo motors to move the blade 20 under test to a suitable position, so that the left edge 25 of the blade can be measured. The data acquisition card inside the system control host collects the photoelectric encoder signals on the X-axis servo motor 12 and the Y-axis servo motor 15 and the photoelectric encoder signal on the electric rotary slide 18 servo motor in real time. At the same time, the system control host sends a trigger signal to the controller of the blade edge laser group 21 to trigger its operation, measure the X-axis and axis coordinate data of the profile of the left edge 25 of the blade at the Z-axis zero point position of the blade 20 under test, record the data through the data acquisition card, and feed it back to the system control host and the measurement display through the fieldbus to display the measurement results in real time.

[0108] (2) Measuring the blade basin 27 of the blade body: The system control host sends control signals to the XY axis servo motors to move the blade 20 to be measured to a suitable position, so that the blade basin 27 of the blade body can be measured. The data acquisition card inside the system control host collects the photoelectric encoder signals on the X-axis servo motor 12 and the Y-axis servo motor 15, as well as the photoelectric encoder signal on the electric rotary slide 18 servo motor in real time. At the same time, the system control host sends a trigger signal to the controller of the blade line laser 22 to trigger its operation and measure the X-axis and axis coordinate data of the profile of the blade basin 27 of the blade body at the Z-axis zero point position of the blade 20 to be measured. The data is recorded through the data acquisition card and fed back to the system control host and the measurement display through the fieldbus to display the measurement results in real time.

[0109] (3) Measuring the right edge 26 of the blade: The system control host controls the servo motor of the electric rotary slide 18 to drive the rotary slide to a suitable position (approximately 180° rotation, the specific position is determined according to the actual model of the blade). The right edge 26 of the blade can be measured. The data acquisition card inside the system control host collects the photoelectric encoder signals on the X-axis servo motor 12 and Y-axis servo motor 15 and the photoelectric encoder signal on the servo motor of the electric rotary slide 18 in real time. At the same time, the system control host sends a trigger signal to the controller of the blade edge laser group 21 to trigger its operation. The system control host measures the contour X-axis and axis coordinate data of the right edge 26 of the blade at the Z-axis zero point position of the blade to be measured. The data is recorded by the data acquisition card and fed back to the system control host and the measurement display through the fieldbus. The measurement results are displayed in real time.

[0110] (4) Measuring the back part 28 of the blade body: The system control host sends control signals to the XY axis servo motors to move the blade to be measured 20 to a suitable position, so that the back part 28 of the blade body can be measured. The data acquisition card inside the system control host collects the photoelectric encoder signals on the X-axis servo motor 12 and the Y-axis servo motor 15, as well as the photoelectric encoder signal on the electric rotary slide 18 servo motor in real time. At the same time, the system control host sends a trigger signal to the controller of the blade body laser 22 to trigger its operation and measure the X-axis and axis coordinate data of the profile of the blade body's blade basin part 27 at the Z-axis zero point position of the blade to be measured 20. The data is recorded through the data acquisition card and fed back to the system control host and the measurement display through the fieldbus to display the measurement results in real time.

[0111] (5) Based on the coordinate transformation principle, the data point clouds of the four parts of the measured blade are combined to obtain the complete blade cross-section data under a fixed Z-axis coordinate. The data of the left leaf edge 25, the right leaf edge 26, the leaf basin part 27, and the leaf back part 28 of the blade collected earlier, as well as the photoelectric encoder signals on the X-axis servo motor 12 and Y-axis servo motor 15 and the photoelectric encoder signal on the electric rotary slide 18 servo motor collected by the system control host at the corresponding measurement position, are combined to obtain the complete blade cross-section data under a fixed Z-axis coordinate.

[0112] Fourth, the Z-axis linear guide 16 moves along the positive Z-axis direction of the blade 20 under test, and the measurement of the blade 20 under test is continued according to the steps in the third step. This process is repeated multiple times to finally obtain the complete blade cross-section of the blade under test in all Z coordinates. All the obtained blade cross-sections are then combined to obtain the complete feature data of the blade.

[0113] In this step, the measurement point cloud of the blade cross-section is first measured at a certain z-axis coordinate, and then measured sequentially along the z-axis coordinate to obtain the complete point cloud of the blade cross-section to be measured.

[0114] Step 4: Based on the position coordinate transformation relationship, transform the complete point cloud of the cross-sectional surface of the blade to be measured to the blade coordinate system, and determine the machining allowance based on the blade theoretical model and the point cloud transformed to the blade coordinate system.

[0115] The measurement point clouds of the left and right leaf edges, as well as the leaf base and back of the blade, obtained by the line laser measurement are transformed into the blade coordinate system through the established transformation relationship (rotation matrix and translation matrix) between the line laser coordinate system and the blade coordinate system in the XY plane. Finally, all the data point clouds of the complete cross-section of the measured blade can be transformed into the blade coordinate system.

[0116] For example: point cloud of leaf-pot data measured by a linear laser array (yb_mea) lineBy obtaining the transformation relationship, the measured data can be transformed from the line laser measurement coordinate system to the blade coordinate system, thus obtaining yb_mea. blade .

[0117] yb_mea blade =R*yb_mea line +T

[0118] The transformation relationship between the two coordinate systems for other measurement areas is the same, which allows us to obtain the complete point cloud of the cross-sectional profile of the blade under the blade coordinate system.

[0119] In step four, the machining allowance of the blade under test can be obtained using the radius search method, which is the distance from the measured point cloud of the actual machined blade to the theoretical cross-sectional profile. Specifically:

[0120] First, determine the search area: Starting from a measurement point in the measurement point cloud of the blade under test, set an initial search radius and define a circular search area with that point as the center and the initial search radius as the radius. Second, search for the minimum distance: Randomly generate a certain number of sample points within the search area, calculate the distance from these sample points to the theoretical cross-sectional surface of the blade, and record the minimum distance and the corresponding sample points. Next, update the search radius: If the found minimum distance is less than the current search radius, it means the minimum distance from the point to the theoretical cross-sectional surface of the blade may be within the current search area; therefore, reduce the search radius and repeat the minimum distance search. If the minimum distance is greater than or equal to the current search radius, expand the search radius and redefine the search area. Then, when the search radius is sufficiently small, or the minimum distance meets certain accuracy requirements, the search is considered converged, and the minimum distance is returned to obtain the machining allowance for that measurement point. Finally, repeat the above steps to obtain the machining allowance for each point on the blade under test.

[0121] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A non-contact blade full feature measuring device characterized by, The measurement device base (7) is provided with a three-dimensional motion module for carrying the blade to be measured to move in three dimensions; A rotating motion module is arranged on the three-dimensional motion module and is used to drive the blade to be measured to rotate, and the rotating motion module comprises a linear laser calibration assembly; A linear laser measurement module is arranged on the measurement device base (7), and the linear laser measurement module comprises a blade edge line laser group (21) and a blade body line laser (22); A control module is arranged, which is used to control the three-dimensional motion module to move so that the blade to be measured and the linear laser calibration assembly enter the working range of the linear laser measurement module, and the control module is used to determine the conversion relationship between the linear laser coordinate system and the blade coordinate system according to the linear laser calibration assembly information obtained by the linear laser measurement module, and the control module is used to determine the machining allowance of the blade to be measured according to the blade information obtained by the linear laser measurement module, the conversion relationship and the blade theoretical model. The blade edge line laser group (21) comprises at least two first lasers arranged along the central axis of the rotating motion module; The blade body line laser (22) comprises a group of second lasers arranged perpendicularly to the first lasers; The linear laser calibration assembly comprises a handle (29), a calibration ball mounting seat (30), a blade basin and back calibration ball group (31) arranged on the calibration ball mounting seat (30), and a blade edge calibration ball group (32) arranged on the calibration ball mounting seat (30). The linear laser measurement module further comprises a first linear laser mounting rack, a second linear laser mounting rack (24) and a two-dimensional translation table (23), the first linear laser mounting rack is used to mount the first laser, the two-dimensional translation table (23) is arranged on the second linear laser mounting rack (24), and the two-dimensional translation table (23) is used to mount the second laser. The three-dimensional motion module comprises a Y-axis motion unit arranged on the base (7), an X-axis motion unit arranged on the Y-axis motion unit, and a Z-axis motion unit arranged on the X-axis motion unit, and the Y-axis motion unit, the X-axis motion unit and the Z-axis motion unit are arranged perpendicularly.

2. The non-contact blade full feature measuring device according to claim 1, wherein, The measurement device further comprises a six-degree-of-freedom robot (2), and the six-degree-of-freedom robot (2) is provided with a blade clamping piece at the end thereof; 3. The non-contact blade full feature measuring device of claim 1, wherein, The measurement device further comprises a measurement cover (3), which is arranged on the measurement device base (7) and provides a sealed working space for the three-dimensional motion module, the rotating motion module and the linear laser measurement module.

4. A non-contact blade full feature measuring device according to any one of claims 1-3, characterized in that, The control module is connected with the three-dimensional motion module, the linear laser measurement module and the six-degree-of-freedom robot (2) through a field bus, and the control module comprises a data acquisition board card used to acquire motor photoelectric encoder information of the three-dimensional motion module and the linear laser measurement module. The method comprises the following steps:

5. A non-contact blade full feature measuring device according to claim 4, wherein, ​ 6. A non-contact blade full-feature measurement method, which is implemented by using the non-contact blade full-feature measurement device according to any one of claims 1-5, characterized in that, ​ The control module constructs a blade theoretical model, divides a measurement region of the blade according to the blade theoretical model and a line laser measurement characteristic, and determines a measurement motion path of the linear laser measurement module, the three-dimensional motion module and the rotary motion module according to the divided measurement region; The linear laser measurement module, the three-dimensional motion module and the rotary motion module are controlled to move cooperatively according to the measurement motion path, so as to measure the blade according to the measurement region and obtain a complete point cloud of a cross-sectional profile of the blade to be measured; The complete point cloud of the cross-sectional profile of the blade to be measured is converted to a blade coordinate system according to a position coordinate conversion relationship, and a machining allowance is determined according to the blade theoretical model and the point cloud converted to the blade coordinate system.

7. The non-contact blade full-feature measurement method of claim 6, wherein, The blade is divided into the measurement region according to the blade theoretical model and the line laser measurement characteristic, including: The blade measurement region is divided according to a line laser measurement range, a measurement curvature and a shape feature of a cross-sectional profile of the blade theoretical model, and the measurement region includes a vane basin, a vane back, a left vane edge and a right vane edge.

8. The non-contact blade full-feature measurement method of claim 6, wherein, Further comprising manufacturing a linear laser calibration assembly according to the specification of the blade to be measured, the blade theoretical model and the line laser measurement characteristic, including: The specification parameters of the stem of the linear laser calibration assembly are obtained according to the specification parameters of the stem of the blade to be measured; The installation positions of the vane basin and back calibration ball groups on the linear laser calibration assembly are determined according to the measurement ranges of the line laser emitters corresponding to the vane basin and back portions of the blade; The installation positions of the vane edge calibration ball groups on the linear laser calibration assembly are determined according to the measurement ranges of the line laser emitters of the line laser groups for measuring the left and right vane edges of the blade.

9. The non-contact blade full-feature measurement method of claim 8, wherein, After the linear laser calibration assembly is manufactured, the linear laser calibration assembly is measured according to the position information of the three-dimensional motion module and the rotary motion module carrying the blade to be measured and the line laser measurement characteristic, and a conversion relationship between the line laser coordinate system and the blade coordinate system is determined, specifically: The linear laser calibration assembly is measured according to a line laser measurement process, and a first point set is obtained; The linear laser calibration assembly is measured using the position information of the three-dimensional motion module and the rotary motion module, and a second point set is obtained; The conversion relationship between the line laser coordinate system and the blade coordinate system is determined according to the first point set and the second point set: Each point in the first point set and the second point set is subtracted by a center point thereof, respectively, to obtain a first center point set and a second center point set; A covariance matrix is determined according to the first center point set and the second center point set, and a rotation matrix and a translation matrix are obtained according to singular value decomposition.

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