A six-axis measurement and error compensation method for an integral blade disk

Abstract

The present invention relates to the technical field of detection of blade profiles of integral blade disks, and specifically discloses a six-axis measurement and error compensation method for integral blade disks, including: constructing a three-coordinate six-axis measuring machine with a turntable as the sixth axis, establishing a spatial error model, and calculating the origin and vector of the rotation axis of the integral blade disk coordinate system; calculating the equivalent rotation matrix of the blade coordinate system after rotation relative to that before rotation based on the origin and vector of the rotation axis; using the Z‑Y‑X Euler angle to obtain the Z‑Y‑X Euler angle equivalent rotation matrix of the blade coordinate system after rotation relative to that before rotation, and solving the measurement compensation value in the Z‑Y‑X Euler angle equivalent rotation matrix; based on the measurement compensation value, realizing the accurate measurement of the circumferential blades of the integral blade disk by the three-coordinate six-axis measuring machine. The six-axis measurement and error compensation method for integral blade disks provided by the present invention improves the measurement accuracy and efficiency of the three-coordinate six-axis measuring machine for integral blade disks, and effectively reduces the measuring range of the measuring machine.

Description

Technical Field

[0001] The present invention relates to the technical field of detecting blade profiles of an integral blade disk, and more specifically, to a six-axis measurement and error compensation method for an integral blade disk. Background Art

[0002] The integral blade disk is widely used in the aviation, national defense, energy and other industries, such as automotive turbochargers, ship gas turbines, aviation engines, and large thermal power steam engines. The blade profile curve, blade surface roughness, front and rear edge curvature radius and shape characteristics largely determine the energy conversion rate of the medium in the working environment, affecting the performance and life of related products. The detection of the integral blade profile is mainly to detect the key dimensions such as the contour and torsion angle of the leading edge, trailing edge, blade basin, and blade back, blade thickness, and blade chord length. Traditional blade detection is mainly manual, among which the standard sample method is the most widely used. Although it is simple to operate and suitable for on-site production, its biggest disadvantage is low accuracy. It can only perform qualitative analysis on the blade profile and cannot obtain accurate measurement errors. At the same time, the new optical detection method is difficult to complete the detection of the blade profile of the integral blade disk, which has a complex free surface, large distortion, and narrow flow channel. The three-coordinate measurement of the integral blade disk has become the most effective means for the detection of the blade profile of the integral blade disk.

[0003] At present, there are two main technical paths for three-coordinate measurement of integral blade disks: one is to use a high-precision three-coordinate measuring machine equipped with a precision turntable to achieve four-axis linkage; the other is to use a multi-axis measuring seat and a high-precision scanning probe for measurement. Although the former is equipped with a fourth-axis precision turntable and a multi-angle trigger probe to improve measurement efficiency, its probe angle is fixed and can only measure integral blade disks with small differences in shape parameters. Its versatility is not high and its cost performance is low; on the other hand, most five-axis measuring machines have not tried to configure a high-precision turntable. Even if the measurement of the entire blade disk is completed through its high-degree-of-freedom dynamic measurement system, for some larger blade disks, there is still a situation where it cannot be measured due to exceeding the lead of the measuring machine, which means that the detection accuracy and cost will be improved, and the detection efficiency will be limited to a certain extent. Therefore, designing a six-axis measurement and error compensation method for integral blade disks is of great significance to improving the detection efficiency and accuracy of rotating integral blade disks. Summary of the invention

[0004] In order to address the deficiencies in the prior art, the present invention provides a six-axis measurement and error compensation method for an integral blade disk, which improves the measurement efficiency of a coordinate measuring machine for a rotating integral blade disk, effectively reduces the detection range of the measuring machine, solves the problem of errors introduced by a turntable, and improves the measurement accuracy.

[0005] As a first aspect of the present invention, a method for six-axis measurement and error compensation of an integral blade disk is provided, comprising the following steps:

[0006] Step S1: construct a three-coordinate six-axis measuring machine with a turntable as the sixth axis;

[0007] Step S2: establishing a spatial error model based on the measurement error introduced by the rotation of the turntable when measuring the integral blade disk;

[0008] Step S3: Calculate the origin P of the rotation axis of the blisk coordinate system and the vector

[0009] Step S4: Based on the origin P of the rotation axis of the blisk coordinate system and the vector Calculate the equivalent rotation matrix of the blade coordinate system after rotation relative to the change before rotation;

[0010] Step S5: using the description of the equivalent rotation matrix by ZYX Euler angles, obtaining the ZYX Euler angle equivalent rotation matrix of the blade coordinate system after rotation relative to that before rotation, and solving the measurement compensation value in the ZYX Euler angle equivalent rotation matrix;

[0011] Step S6: Based on the measurement compensation value in the ZYX Euler angle equivalent rotation matrix, the three-coordinate six-axis measuring machine is used to accurately measure the circumferential blades of the integral blade disk.

[0012] Furthermore, the three-coordinate six-axis measuring machine with a turntable as the sixth axis further comprises:

[0013] After verifying that the accuracy of the turntable as the sixth axis meets the standard, the configuration of the three-coordinate six-axis measuring machine is completed. The entire configuration process includes three parts: hardware connection, UCC software configuration and turntable parameter adjustment. Amplifier SPA3 is used as the UCC controller to control the transfer of the air-floating turntable movement. After the hardware connection is completed, the UCC software system is matched, and the current loop, speed loop and position loop parameters of the air-floating turntable are adjusted. If the UCC controller realizes the successful return to zero of the air-floating turntable under the software and hardware control, the configuration of the three-coordinate six-axis measuring machine is completed.

[0014] Furthermore, according to the spatial error model, the origin P of the rotation axis and the vector According to the origin P of the rotation axis of the blisk coordinate system and the vector Calculate the equivalent rotation matrix of the blade coordinate system after rotation relative to the change before rotation, including:

[0015] The integral blade disk coordinate system rotates around the central axis of the turntable coordinate system. When any one of the X-axis, Y-axis and Z-axis of the turntable coordinate system is selected as the rotation axis, the equivalent rotation matrix R of the blade coordinate system after rotation relative to that before rotation isK (θ) is:

[0016]

[0017] Where cθ = cosθ, sθ = sinθ, vθ = 1-cosθ, and is the unit vector of the rotation axis, θ is the rotation angle of the integral blade disk with the turntable relative to the initial position, and its sign is determined by the right-hand rule, that is, the thumb points to the direction of the rotation axis vector; at this time, the unit vector of the rotation axis The description of the starting point P is in the coordinate system of the first blade, when solving the equivalent rotation matrix R K Before (θ), it is necessary to determine and starting point The description of the first blade coordinate system relative to the turntable coordinate system is It can be expressed by the unit direction component of the principal axis unit vector in the turntable coordinate system:

[0018]

[0019]

[0020] Where ΔX BC1 , ΔY BC1 , ΔZ BC1 is the translation amount of the first blade coordinate system relative to the turntable coordinate system, is the principal axis vector of the first blade coordinate system relative to the turntable coordinate system, is the description of the turntable coordinate system relative to the first blade coordinate system, from The origin P of the rotation axis and the vector

[0021] Furthermore, it also includes:

[0022] According to the origin P of the rotation axis and the vector Calculate the equivalent rotation matrix R of the blade coordinate system {Ci} at the θ-degree position of the integral blade disk relative to the blade coordinate system {C1} at the 0-degree position of the integral blade disk before rotation after the turntable rotates by an angle of θ K (θ);

[0023] Assume that the blade coordinate system {C1} at the 0 degree position of the integral blade disk before rotation is the first blade coordinate system of the integral blade disk, and the blade coordinate system {Ci} at the θ degree position of the integral blade disk after rotation is the i-th blade coordinate system of the integral blade disk;

[0024] First, define two new coordinate systems {C1'} and {Ci'}, which coincide with each other and have the same direction relative to the first blade coordinate system {C1} and the i-th blade coordinate system {Ci}, respectively. The origin P is the starting point of the rotation vector The description of the coordinate system {C1'} relative to the first blade coordinate system {C1} is:

[0025]

[0026] Similarly, the description of the i-th blade coordinate system {Ci} relative to the coordinate system {Ci'} is:

[0027]

[0028] The coordinate system {Ci'} rotates around the coordinate system {C1'}, and the rotation axis passes through the origin P. Combined with the equivalent rotation matrix R K (θ) Find the description of the coordinate system {Ci'} relative to the coordinate system {C1'} Then the description of the i-th blade coordinate system {Ci} after rotation relative to the first blade coordinate system {C1} before rotation is for:

[0029]

[0030] Finally, according to the above transformation equation, the description of the i-th blade coordinate system {Ci} after rotation relative to the first blade coordinate system {C1} before rotation is obtained:

[0031] Further, the description of the equivalent rotation matrix using ZYX Euler angles, obtaining the ZYX Euler angle equivalent rotation matrix of the blade coordinate system after rotation relative to that before rotation, and solving the measurement compensation value in the ZYX Euler angle equivalent rotation matrix, also includes:

[0032] The measurement compensation values ​​in the ZYX Euler angle equivalent rotation matrix include the X-axis rotation angle γ, the Y-axis rotation angle β, the Z-axis rotation angle α and the translation amounts ΔX, ΔY and ΔZ of the three axes;

[0033] According to the matrix Get the coordinate system {C i} Rotation transformation relative to {C1} And translation transformation The Euler angles of ZYX are used to describe the rotation of the coordinate system {C1}. First, the coordinate system {C1} is rotated around the Z axis by an angle of α, then around the Y axis by an angle of β, and finally around the X axis by an angle of γ. In this representation, each rotation angle is relative to the previous rotation. The coordinate system {C i}ZYX Euler angle equivalent rotation matrix relative to coordinate system {C1} for:

[0034]

[0035] In the formula, cα=cosα,sα=sinα,sβ=sinβ,cβ=cosβ,cγ=cosγ,sγ=sinγ; To solve the ZYX Euler angle equivalent rotation matrix The compensation values ​​in the matrix, the X-axis rotation angle γ, the Y-axis rotation angle β, the Z-axis rotation angle α and the three-axis translation ΔX, ΔY and ΔZ, can be converted into To find the inverse solution, we can use the matrix The rotation 3×3 matrix is ​​considered as:

[0036]

[0037] Combining the above two formulas, we can obtain the X-axis rotation angle γ, Y-axis rotation angle β, and Z-axis rotation angle α:

[0038] α=atan2(r 21 ,r 11 )

[0039]

[0040] γ=atan2(r 32 ,r 33 )

[0041] Where atan2(y,x) is Matlab's inverse tangent function of two parameters, and the Euler angles are in the following ranges: -π<α<π, -π / 2<β<π / 2, -π<γ<π.

[0042] Furthermore, the three-coordinate six-axis measuring machine is used to accurately measure the circumferential blades of the integral blade disk according to the measurement compensation value in the ZYX Euler angle equivalent rotation matrix, and further includes:

[0043] Get the coordinate system of the first blade of the integral blade disk;

[0044] In the first blade coordinate system, using the three-coordinate six-axis measuring machine to measure the first blade of the integral blade disk;

[0045] When the three-coordinate six-axis measuring machine measures the i-th blade corresponding to the angle θ of the integral blade disk, i=2, 3, 4..., the measurement process of the i-th blade remains consistent, the turntable only needs to rotate a certain angle θ, and the measurement compensation value is input into the three-coordinate six-axis measuring machine. The probe of the three-coordinate six-axis measuring machine measures the i-th blade of the integral blade disk in the original orientation and original position, and this step is repeated to complete the measurement of all blades around the circumference of the integral blade disk.

[0046] The six-axis measurement and error compensation method for the integral blade disk provided by the present invention has the following advantages: combining the advantages of four-axis linkage and five-axis measuring seat to detect the integral blade disk, improving the measurement efficiency of the coordinate measuring machine for the rotating integral blade disk, effectively reducing the detection range of the measuring machine, solving the problem of error introduced by the turntable, and improving the measurement accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] The accompanying drawings are used to provide further understanding of the present invention and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present invention, but do not constitute a limitation of the present invention.

[0048] Figure 1 A schematic diagram of error detection of a coordinate measuring machine with a turntable provided by the present invention having an axis as the sixth axis.

[0049] Figure 2 This is a configuration flow chart of the three-coordinate six-axis measuring machine provided by the present invention.

[0050] Figure 3A This is a two-dimensional spatial error model diagram provided by the present invention.

[0051] Figure 3B This is a three-dimensional space error model diagram provided by the present invention.

[0052] Figure 4 A schematic diagram of the blade coordinate system transformation rotating around a vector axis provided by the present invention.

[0053] Figure 5 This is a schematic diagram of the ZYX Euler angle rotation description provided by the present invention.

[0054] Figure 6 This is a flow chart of the six-axis measurement and error compensation method of the integral blade disk provided by the present invention. DETAILED DESCRIPTION

[0055] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation method, structure, characteristics and effects of the six-axis measurement and error compensation method of the integral blade disk proposed by the present invention are described in detail below in combination with the accompanying drawings and preferred embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the protection scope of the present invention.

[0056] In this embodiment, a six-axis measurement and error compensation method for an integral blade disk is provided. Figure 6 As shown, the six-axis measurement and error compensation method of the integral blade disk includes:

[0057] Step S1: construct a three-coordinate six-axis measuring machine with a turntable as the sixth axis; calibrate the configured turntable, establish the turntable coordinate system, and determine the position and posture of the turntable coordinate system relative to the machine tool coordinate system.

[0058] Step S2: Analyze the turntable as the sixth axis of the coordinate measuring machine, establish two-dimensional and three-dimensional spatial error models based on the measurement error introduced by the rotation of the turntable when measuring the integral blade disk; and extract the position of the turntable coordinate system and the measured integral blade disk coordinate system relative to the machine tool coordinate system and the axis vectors.

[0059] Step S3: Calculate the origin P of the rotation axis of the blisk coordinate system and the vector

[0060] Step S4: Based on the origin P of the rotation axis of the blisk coordinate system and the vector Calculate the equivalent rotation matrix of the blade coordinate system after rotation relative to the change before rotation;

[0061] Step S5: using the description of the equivalent rotation matrix by ZYX Euler angles, obtaining the ZYX Euler angle equivalent rotation matrix of the blade coordinate system after rotation relative to that before rotation, and solving the measurement compensation value in the ZYX Euler angle equivalent rotation matrix;

[0062] Step S6: Based on the measurement compensation value in the ZYX Euler angle equivalent rotation matrix, the three-coordinate six-axis measuring machine is used to accurately measure the circumferential blades of the integral blade disk.

[0063] Preferably, if Figure 2 As shown, the three-coordinate six-axis measuring machine with a turntable as the sixth axis also includes:

[0064] After verifying that the accuracy of the turntable as the sixth axis meets the standard, the configuration of the three-coordinate six-axis measuring machine is completed. The entire configuration process includes three parts: hardware connection, UCC software configuration and turntable parameter adjustment. Amplifier SPA3 is used as the UCC controller to control the transfer of the air-floating turntable movement. After the hardware connection is completed, the UCC software system is matched, and the current loop, speed loop and position loop parameters of the air-floating turntable are adjusted. If the UCC controller realizes the successful return to zero of the air-floating turntable under the software and hardware control, the configuration of the three-coordinate six-axis measuring machine is completed.

[0065] Specifically, Figure 1 As shown, the ISO 10360-3 and GB / T16857.3-2009 standards are first used to test the accuracy of the configuration turntable. After the accuracy meets the standard, the three-coordinate measurement system is configured and calibrated to build a six-axis measurement system. Then, based on the principle of robotics space coordinate system transformation, a spatial model between coordinate systems is established, the spatial error between the turntable coordinate system and the part coordinate system that rotates a certain angle is analyzed, and the error introduced by the configuration of the sixth-axis turntable is accurately compensated to achieve the detection of the entire blade disk by the entire system. The configuration process of the three-coordinate six-axis measuring machine is as follows:

[0066] Step 1: According to the acceptance inspection document of the coordinate measuring machine, design an error detection scheme for the coordinate measuring machine with the turntable as the sixth axis to verify the turntable accuracy;

[0067] It should be noted that according to the acceptance inspection document of coordinate measuring machine "Product Geometry Technical Specification (GPS) Acceptance Inspection and Re-inspection Inspection of Coordinate Measuring Machine Part 3: Coordinate Measuring Machine with Turntable as the Fourth Axis", the error detection scheme of coordinate measuring machine with turntable as the sixth axis is designed, such as Figure 1 As shown, two standard balls are mounted and fixed on an air-floating turntable, ball A is a high ball, ball B is a bottom ball, the sphericity error of the two balls is less than 1 μm, and the height difference between them is Δh.

[0068] Step 2: Build a test platform and use a five-axis coordinate measuring machine to collect the coordinates of the standard sphere center at different turntable angles in the machine tool coordinate system;

[0069] It should be noted that the test platform is built according to step 1, and the coordinates of the standard sphere center at different turntable angles in the machine tool coordinate system are collected using a five-axis coordinate measuring machine. The coordinates of the sphere centers of the two balls are measured at different angles, and a sphere center coordinate system with two balls is established. The measurements are repeated by rotating at different angles. The coordinates of the center of sphere A are collected when the turntable angle is 0°, 75°, 125°, 385°, 410°, 510°, and 820°, and the coordinates of the center of sphere B are collected when the turntable angle is 0°, 60°, 75°, 125°, 385°, 410°, 510°, 820°, -75°, -125°, -175°, -385°, -410°, -510°, and -820°. For each point collected on the sphere, set an appropriate approximation and retraction distance, and let the machine proceed automatically to avoid data deviation caused by uneven measurement force during manual point collection. Finally, record and output the point set coordinates.

[0070] Step 3: Use the point set coordinates collected in step 2 to establish the spherical center coordinate system, process all A and B coordinates, and calculate the standard sphere radial error FR, tangential error FT and axial error FA;

[0071] Step 4: According to the turntable accuracy level evaluation standard, determine the accuracy level of the turntable configured as the sixth axis of the coordinate measuring machine;

[0072] It should be noted that the accuracy level of the turntable is judged by selecting the tightest tolerance of its detection accuracy as the initial benchmark and selecting the judgment factor, which is 1 / 10 tolerance for general requirements, 1 / 15 tolerance for strict requirements, and 1 / 20 tolerance for ultra-high requirements. When the error evaluation of each axis tested in step 3 meets the corresponding tightest tolerance multiplied by the judgment factor, it indicates that the turntable accuracy meets the corresponding accuracy requirements. Determine the accuracy level of the turntable configured as the sixth axis of the coordinate measuring machine.

[0073] Step 5: After verifying that the turntable accuracy in step 4 meets the standard, complete the configuration of the turntable software and hardware in the five-axis coordinate measuring machine and integrate the three-coordinate six-axis measurement system. The specific process is as follows: Figure 2 shown.

[0074] Step 6: The configured turntable needs to be calibrated. The process is to determine the Z-axis vector and height based on the turntable plane normal, and determine the X-axis and Y-axis origins by fitting the circle with the center of the standard ball fixed on the turntable after the turntable rotates one circle. After the turntable coordinate system is established, the six-axis detection system can determine the position and posture of the turntable coordinate system relative to the machine tool coordinate system and generate an interactive interface.

[0075] Preferably, if Figure 3A-3B As shown, according to the spatial error model, the origin P of the rotation axis and the vector According to the origin P of the rotation axis of the blisk coordinate system and the vector Calculate the equivalent rotation matrix of the blade coordinate system after rotation relative to the change before rotation, including:

[0076] The calculation of the blade coordinate system compensation value before and after rotation is actually to determine the position and attitude transformation relationship of the blade disk coordinate system {C} relative to the machine tool coordinate system {A} and the turntable coordinate system {B} before and after rotation.

[0077] After the turntable is calibrated and the coordinate system is precisely constructed, the precise relative positions of {C}, {B} and {A} can be obtained.

[0078] use and represents the i-th leaf coordinate system {C i}The spindle unit vector relative to the machine tool coordinate system {A}.

[0079] use and Represents the spindle unit vector of the turntable coordinate system {B} relative to the machine tool coordinate system {A}.

[0080] The integral blade coordinate system {C} rotates around the central axis of the turntable coordinate system {B}. When any one of the X-axis, Y-axis and Z-axis of the turntable coordinate system {B} is selected as the rotation axis, the equivalent rotation matrix R of the blade coordinate system after rotation relative to the change before rotation is K (θ) is:

[0081]

[0082] Where cθ = cosθ, sθ = sinθ, vθ = 1-cosθ, and is the unit vector of the rotation axis, θ is the rotation angle of the integral blade disk with the turntable relative to the initial position, and its sign is determined by the right-hand rule, that is, the thumb points to the direction of the rotation axis vector; at this time, the unit vector of the rotation axis The description of the starting point P is in the coordinate system of the first blade, when solving the equivalent rotation matrix R K Before (θ), it is necessary to determine and starting point The description of the first blade coordinate system relative to the turntable coordinate system is It can be expressed by the unit direction component of the principal axis unit vector in the turntable coordinate system:

[0083]

[0084] Where ΔX BC1 , ΔY BC1 , ΔZ BC1is the translation of the first blade coordinate system {C1} relative to the turntable coordinate system {B}. Generally, the turntable is placed horizontally on the platform of the coordinate machine. After calibration, the first blade coordinate system {C1} is relative to the main axis unit vector of the turntable coordinate system {B} is the same as the unit vector of {C1} relative to the principal axis of {A}, that is, Can be used express.

[0085] At the same time, {B} is described relative to {C1} can be The transpose of gets:

[0086]

[0087] In the formula, is the principal axis vector of the first blade coordinate system relative to the turntable coordinate system, is the description of the turntable coordinate system relative to the first blade coordinate system, from The origin P of the rotation axis and the vector Combination and The data can accurately derive the vector and matrix The value of can be regarded as the offset ΔX of the coordinate system {B} relative to {C1} C1B , ΔY C1B and ΔZ C1B .

[0088] It should be noted that if Figure 3A-3B As shown in the figure, after the three-dimensional coordinate measuring machine is equipped with an air-bearing turntable, the measurement of the circumferential blades of the integral blade disk can be achieved through the rotation of the air-bearing turntable, that is, after measuring the i-th (i=1,2,3...) blade, to measure the i+1-th blade, it is only necessary to rotate the turntable by an angle value to achieve measurement on the new blade. However, in the actual measurement process, the rotation axis of the blade disk coordinate system cannot be completely consistent with the rotation axis of the air-bearing turntable, and the rotation motion will introduce position errors in the blade coordinate system. When the XY plane of the turntable coordinate system is approximately parallel to the plane formed by any axis of the integral blade disk coordinate system, the point error before and after the rotation of the integral blade disk coordinate system can be converted into a two-dimensional error on the projection of the XY plane of the machine tool coordinate system, such as Figure 3A As shown in the figure, after the blade disk rotates counterclockwise with the turntable at an angle of θ, there is an error between the blade coordinate system of the blade disk at 0 degrees before rotation and the blade coordinate system of the blade disk at θ degrees after rotation, and the error increases with the increase of the rotation angle. Extended to three dimensions, when there is a certain angle between the XY plane of the turntable coordinate system and the plane formed by any axis of the blade disk coordinate system, such as Figure 3BAs shown in the figure, the spatial error of the three-dimensional point is more significant. Therefore, eliminating the measurement error introduced by the turntable is the key to complete accurate detection. Since the error values ​​of different points on the blade surface are different, when there is no universal compensation method, the compensation workload will increase and the measurement efficiency will be reduced. Therefore, the error compensation of the point is converted into the spatial position and attitude error compensation of the coordinate system.

[0089] It should be understood that if Figure 3A-3B As shown in the figure, by rotating the turntable for a certain angle, the other blades on the integral blade disk are rotated in turn to the blade coordinate system {C1} where the first blade is located for measurement. However, in the actual measurement process, due to errors, the other blades are not rotated to the blade coordinate system {C1} where the first blade is located. If the other blades are still measured in the previous first blade coordinate system {C1}, there will be errors. Therefore, it is necessary to add a compensation value to the first blade coordinate system {C1} in the three-coordinate six-axis measuring machine to obtain the coordinate system of the actual rotation position of the other blades, and then measure them in turn through the probe.

[0090] Preferably, if Figure 4 As shown, it also includes:

[0091] According to the origin P of the rotation axis and the vector Calculate the equivalent rotation matrix R of the blade coordinate system {Ci} at the θ-degree position of the integral blade disk relative to the blade coordinate system {C1} at the 0-degree position of the integral blade disk before rotation after the turntable rotates by an angle of θ K (θ);

[0092] Assume that the blade coordinate system {C1} at the 0 degree position of the integral blade disk before rotation is the first blade coordinate system of the integral blade disk, and the blade coordinate system {Ci} at the θ degree position of the integral blade disk after rotation is the i-th blade coordinate system of the integral blade disk;

[0093] First, define two new coordinate systems {C1'} and {Ci'}, which coincide with each other and have the same direction relative to the first blade coordinate system {C1} and the i-th blade coordinate system {Ci}, respectively. The origin P is the starting point of the rotation vector The description of the coordinate system {C1'} relative to the first blade coordinate system {C1} is:

[0094]

[0095] Similarly, the description of the i-th blade coordinate system {Ci} relative to the coordinate system {Ci'} is:

[0096]

[0097] The coordinate system {Ci'} rotates around the coordinate system {C1'}, and the rotation axis passes through the origin P. Combined with the equivalent rotation matrix R K(θ) Find the description of the coordinate system {Ci'} relative to the coordinate system {C1'} Then the description of the i-th blade coordinate system {Ci} after rotation relative to the first blade coordinate system {C1} before rotation is for:

[0098]

[0099] Finally, according to the above transformation equation, the description of the i-th blade coordinate system {Ci} after rotation relative to the first blade coordinate system {C1} before rotation is obtained:

[0100] Preferably, if Figure 5 As shown, it indicates the axis change of the coordinate system {C1} after each Euler angle transformation, the description of the equivalent rotation matrix using ZYX Euler angles, obtains the ZYX Euler angle equivalent rotation matrix of the blade coordinate system after rotation relative to the change before rotation, and solves the measurement compensation value in the ZYX Euler angle equivalent rotation matrix, and also includes:

[0101] The measurement compensation values ​​in the ZYX Euler angle equivalent rotation matrix include the X-axis rotation angle γ, the Y-axis rotation angle β, the Z-axis rotation angle α and the translation amounts ΔX, ΔY and ΔZ of the three axes;

[0102] According to the matrix Get the coordinate system {C i} Rotation transformation relative to {C1} And translation transformation The Euler angles of ZYX are used to describe the rotation of the coordinate system {C1}. First, the coordinate system {C1} is rotated counterclockwise around its own Z axis by an angle α, then around its own Y axis by an angle β, and finally around its own X axis by an angle γ. In this representation, each rotation angle is relative to the previous rotation, and the resulting axis is appended with an "apostrophe". The coordinate system {C1} i}ZYX Euler angle equivalent rotation matrix relative to coordinate system {C1} for:

[0103]

[0104] In the formula, cα=cosα,sα=sinα,sβ=sinβ,cβ=cosβ,cγ=cosγ,sγ=sinγ; To solve the ZYX Euler angle equivalent rotation matrix The compensation values ​​in the matrix, the X-axis rotation angle γ, the Y-axis rotation angle β, the Z-axis rotation angle α and the three-axis translation ΔX, ΔY and ΔZ, can be converted into To find the inverse solution, we can use the matrix The rotation 3×3 matrix is ​​considered as:

[0105]

[0106] Combining the above two formulas, we can obtain the X-axis rotation angle γ, Y-axis rotation angle β, and Z-axis rotation angle α:

[0107] α=atan2(r 21 ,r 11 )

[0108]

[0109] γ=atan2(r 32 ,r 33 )

[0110] Where atan2(y,x) is Matlab's inverse tangent function of two parameters, and the Euler angles are in the following ranges: -π<α<π, -π / 2<β<π / 2, -π<γ<π.

[0111] It should be noted that the coordinate system {C1} to {C i After obtaining the rotation ZYX Euler angle and offset of the measuring machine, the compensation value is input into the control program of the measuring machine to complete the error compensation of the overall blade disk coordinate system caused by the rotation of the turntable.

[0112] Preferably, the method of realizing accurate measurement of the circumferential blades of the blisk by the three-coordinate six-axis measuring machine based on the measurement compensation value in the ZYX Euler angle equivalent rotation matrix further includes:

[0113] Get the coordinate system of the first blade of the integral blade disk;

[0114] In the first blade coordinate system, using the three-coordinate six-axis measuring machine to measure the first blade of the integral blade disk;

[0115] It should be noted that a measurement program for the entire blade disk is compiled to establish a rough reference coordinate system for the first blade, and then an iterative method is used to measure multiple points on the first blade to establish a precise reference coordinate system of the zero point, wherein the establishment of the precise coordinate system of the entire blade disk has been completed in step S2. After the blade measurement program of the measuring machine is compiled, the measurement of the first blade can be realized.

[0116] When the measurement of the first blade is completed, when the three-coordinate six-axis measuring machine measures the i-th blade corresponding to the angle θ of the integral blade disk, i=2,3,4..., the measurement process of the i-th blade remains consistent, and the turntable only needs to rotate a certain angle θ, and the measurement compensation value is input into the control program in the three-coordinate six-axis measuring machine. The probe of the three-coordinate six-axis measuring machine measures the i-th blade of the integral blade disk in the original orientation and original position, and this step is repeated to complete the measurement of all blades around the circumference of the integral blade disk.

[0117] It should be understood that when the turntable rotates at zero degrees, the positions of the turntable coordinate system and the measured blisk fine-construction coordinate system relative to the machine tool coordinate system and the vector data of each axis are extracted. The fine-construction coordinate system process of the blisk is based on the reference plane and reference hole features to determine the rotation axis and XY plane of the blisk. Then, a point is measured on the first blade as the angle phase to constrain the coordinate system posture and complete the establishment of the zero-position rough coordinate system. Then, multiple points on the first blade are selected and the fine coordinate system of the blisk is established using an iterative method, that is, the first blade coordinate system {C1} is obtained.

[0118] The six-axis measurement and error compensation method for the integral blade disk provided by the present invention realizes the configuration of a turntable on a five-axis coordinate measuring machine, realizes the measurement of key parameters such as the contour, torsion angle, maximum thickness, etc. of all blades around the circumference of the integral blade disk, improves the measurement accuracy and efficiency of the three-coordinate measuring machine for the integral blade disk, and effectively reduces the measuring range of the measuring machine.

[0119] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with this profession can make some changes or modifications to equivalent embodiments of equivalent changes using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the scope of the technical solution of the present invention.

Claims

1. A six-axis measurement and error compensation method for an integral blade disk, characterized in that: The following steps are involved: Step S1: construct a three-coordinate six-axis measuring machine with a turntable as the sixth axis; Wherein, the three-coordinate six-axis measuring machine with a turntable as the sixth axis also includes: After verifying that the accuracy of the turntable as the sixth axis meets the standard, the configuration of the three-coordinate six-axis measuring machine is completed. The entire configuration process includes three parts: hardware connection, UCC software configuration and turntable parameter adjustment. Amplifier SPA3 is used as the UCC controller to control the transfer of the air-floating turntable movement. After the hardware connection is completed, the UCC software system is matched, and the current loop, speed loop and position loop parameters of the air-floating turntable are adjusted. If the UCC controller realizes the software and hardware control of the air-floating turntable to successfully return to zero, the configuration of the three-coordinate six-axis measuring machine is completed; Step S2: establishing a spatial error model based on the measurement error introduced by the rotation of the turntable when measuring the integral blade disk; Step S3: Calculate the origin P of the rotation axis of the blisk coordinate system and the vector Step S4: Based on the origin P of the rotation axis of the blisk coordinate system and the vector Calculate the equivalent rotation matrix of the blade coordinate system after rotation relative to the change before rotation; Wherein, according to the spatial error model, the origin P of the rotation axis and the vector According to the origin P of the rotation axis of the blisk coordinate system and the vector Calculate the equivalent rotation matrix of the blade coordinate system after rotation relative to the change before rotation, including: The integral blade disk coordinate system rotates around the central axis of the turntable coordinate system. When any one of the X-axis, Y-axis and Z-axis of the turntable coordinate system is selected as the rotation axis, the equivalent rotation matrix R of the blade coordinate system after rotation relative to that before rotation is K (θ) is: Where cθ = cosθ, sθ = sinθ, vθ = 1-cosθ, and is the unit vector of the rotation axis, θ is the rotation angle of the integral blade disk with the turntable relative to the initial position, and its sign is determined by the right-hand rule, that is, the thumb points to the direction of the rotation axis vector; at this time, the unit vector of the rotation axis The description of the starting point P is in the coordinate system of the first blade, when solving the equivalent rotation matrix R K Before (θ), it is necessary to determine and starting point The description of the first blade coordinate system relative to the turntable coordinate system is It can be expressed by the unit direction component of the principal axis unit vector in the turntable coordinate system: Where ΔX BC1 , ΔY BC1 , ΔZ BC1 is the translation amount of the first blade coordinate system relative to the turntable coordinate system, is the principal axis vector of the first blade coordinate system relative to the turntable coordinate system, is the description of the turntable coordinate system relative to the first blade coordinate system, from The origin P of the rotation axis and the vector Among them, it also includes: According to the origin P of the rotation axis and the vector After the turntable rotates by an angle of θ, the equivalent rotation matrix R of the blade coordinate system {Ci} at the θ-degree position of the integral blade disk relative to the blade coordinate system {C1} at the 0-degree position of the integral blade disk before rotation is calculated. K (θ); Assume that the blade coordinate system {C1} at the 0 degree position of the integral blade disk before rotation is the first blade coordinate system of the integral blade disk, and the blade coordinate system {Ci} at the θ degree position of the integral blade disk after rotation is the i-th blade coordinate system of the integral blade disk; First, define two new coordinate systems {C1'} and {Ci'}, which coincide with each other and have the same direction relative to the first blade coordinate system {C1} and the i-th blade coordinate system {Ci}, respectively. The origin P is the starting point of the rotation vector The description of the coordinate system {C1'} relative to the first blade coordinate system {C1} is: Similarly, the description of the i-th blade coordinate system {Ci} relative to the coordinate system {Ci'} is: The coordinate system {Ci'} rotates around the coordinate system {C1'}, and the rotation axis passes through the origin P. Combined with the equivalent rotation matrix R K (θ) Find the description of the coordinate system {Ci'} relative to the coordinate system {C1'} Then the description of the i-th blade coordinate system {Ci} after rotation relative to the first blade coordinate system {C1} before rotation is for: Finally, transform the equation to find the description of the i-th blade coordinate system {Ci} after rotation relative to the first blade coordinate system {C1} before rotation Step S5: using the description of the equivalent rotation matrix by ZYX Euler angles, obtaining the ZYX Euler angle equivalent rotation matrix of the blade coordinate system after rotation relative to that before rotation, and solving the measurement compensation value in the ZYX Euler angle equivalent rotation matrix; Wherein, the description of the equivalent rotation matrix using ZYX Euler angles, obtaining the ZYX Euler angle equivalent rotation matrix of the blade coordinate system after rotation relative to that before rotation, and solving the measurement compensation value in the ZYX Euler angle equivalent rotation matrix, also includes: The measurement compensation values ​​in the ZYX Euler angle equivalent rotation matrix include the X-axis rotation angle γ, the Y-axis rotation angle β, the Z-axis rotation angle α and the translation amounts ΔX, ΔY and ΔZ of the three axes; According to the matrix Get the coordinate system {C i } Rotation transformation relative to {C1} And translation transformation The Euler angles of ZYX are used to describe the rotation of the coordinate system {C1}. First, the coordinate system {C1} is rotated around the Z axis by an angle of α, then around the Y axis by an angle of β, and finally around the X axis by an angle of γ. In this representation, each rotation angle is relative to the previous rotation. The coordinate system {C i }ZYX Euler angle equivalent rotation matrix relative to coordinate system {C1} for: In the formula, cα=cosα,sα=sinα,sβ=sinβ,cβ=cosβ,cγ=cosγ,sγ=sinγ; To solve the ZYX Euler angle equivalent rotation matrix The compensation values ​​in the matrix, the X-axis rotation angle γ, the Y-axis rotation angle β, the Z-axis rotation angle α and the three-axis translation ΔX, ΔY and ΔZ, can be converted into To find the inverse solution, we can use the matrix The rotation 3×3 matrix is ​​considered as: Combining the two formulas, we can obtain the X-axis rotation angle γ, the Y-axis rotation angle β, and the Z-axis rotation angle α: α=atan2(r 21 ,r 11 ) γ=atan2(r 32 ,r 33 ) Where atan2(y,x) is Matlab's inverse tangent function of two parameters, and the Euler angles will be in the following ranges: -π<α<π, -π / 2<β<π / 2, -π<γ<π; Step S6: according to the measurement compensation value in the ZYX Euler angle equivalent rotation matrix, the three-coordinate six-axis measuring machine is used to accurately measure the circumferential blades of the integral blade disk; Wherein, the method of realizing accurate measurement of the circumferential blades of the integral blade disk by the three-coordinate six-axis measuring machine according to the measurement compensation value in the ZYX Euler angle equivalent rotation matrix also includes: Get the coordinate system of the first blade of the integral blade disk; In the first blade coordinate system, using the three-coordinate six-axis measuring machine to measure the first blade of the integral blade disk; When the three-coordinate six-axis measuring machine measures the i-th blade corresponding to the angle θ of the integral blade disk, i=2, 3, 4..., the measurement process of the i-th blade remains consistent, the turntable only needs to rotate a certain angle θ, and the measurement compensation value is input into the three-coordinate six-axis measuring machine. The probe of the three-coordinate six-axis measuring machine measures the i-th blade of the integral blade disk in the original orientation and original position, and this step is repeated to complete the measurement of all blades around the circumference of the integral blade disk.

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