Throat detection reference coordinate system establishing method
Through three -coordinate measuring machine measurement benchmark end surface and circle, combined with the actual measurement value and theoretical value differences of the measurement point to modify the coordinate system, solve the problem of the lack of positioning feature holes of the guidance device component, and realize the accuracy and extensive measurement of the throat area measurement and extensive applicability.
Patent Information
- Application Number
- CN202310897931.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-07-20
- Publication Date
- 2025-01-21
AI Technical Summary
In the prior art, some guide components lack positioning feature holes, resulting in the inability to establish a coordinate system and thus the throat area measurement cannot be performed.
The reference end face and reference circle are measured by a three-dimensional coordinate measuring machine to establish an initial coordinate system, and the coordinate system is corrected based on the difference between the actual measured value and the theoretical value of the measuring point until the error tolerance is met.
It realizes the establishment of a coordinate system on the guide component that lacks positioning feature holes, solves the problem of throat area measurement, and improves the measurement accuracy and scope of application.
Smart Images
Figure CN119334299A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the field of guide throat area calculation methods, and in particular to a method for establishing a throat detection reference coordinate system. Background Art
[0002] The minimum exhaust edge area in the convergent channel of the gas flowing through the guide is called the guide throat area. The size of the turbine guide throat area directly affects the performance of the engine. Practice has shown that the changes in the throat area of the high-pressure turbine I-stage guide and the throat area of the low-pressure turbine I-stage guide have an impact on the engine's high-pressure speed, thrust, M2 performance, T4 temperature, and fuel consumption rate. Therefore, the throat area of the engine blade is an important parameter for engine assembly and debugging, and the measurement of the throat area is the key to blade assembly.
[0003] Usually, the throat of a blade is a space curved channel formed by the upper edge plate, lower edge plate and blade body profile of each two guide vanes. The throat area measuring tool designed in the research can accurately detect the channel width dimension of the specified cross section between each channel window and the channel height dimension of the upper and lower edge plates to calculate the throat area of the blade. The flow rate of the throat area is related to the thrust of the engine. The blade throat area measuring tool obtains the uniformity of the exhaust volume of the blade channel, which is the key to the engine performance analysis.
[0004] At present, the common method for measuring the throat area is to use a three-dimensional coordinate measuring machine for measurement. The measurement process is to place the turntable on the three-dimensional coordinate measuring machine, and then place the casing unit with the guide assembly on the turntable, align the center, that is, the axis of the turbine guide coincides with the axis of the turntable. Then use the three-dimensional coordinate measuring machine to measure the area of the first window. After the measurement is completed, the turntable is controlled to move a division angle phase, and then the area of the next window is measured.
[0005] This measurement method requires a reference plane to locate a coordinate axis of the coordinate system during the measurement process. Here, this coordinate axis is defined as the X-axis and the X-coordinate of the origin. Then, the Y and Z coordinates of the origin of the coordinate system need to be located through a precision circle or cylinder. Finally, the Z axis of the coordinate system is defined through a positioning feature hole (usually a hole on the circumferential pitch circle). In this way, the coordinate system can be established.
[0006] However, in actual processes, some guide components do not have features such as positioning feature holes that define the Z-axis of the coordinate system, which results in the inability to establish the coordinate system during the measurement process and thus the inability to continue the measurement.
[0007] In view of this, the inventor of the present application has designed a method for establishing a throat detection reference coordinate system in order to solve the above technical problems. Summary of the invention
[0008] The technical problem to be solved by the present invention is to overcome the defect in the prior art that some guide components do not have a positioning feature hole such as a feature for defining the Z-axis of the coordinate system, resulting in the inability to establish a coordinate system during the guide throat area measurement process and thus the inability to continue the measurement, and a method for establishing a throat detection reference coordinate system is provided.
[0009] The present invention solves the above technical problems through the following technical solutions:
[0010] The present invention provides a method for establishing a reference coordinate system for throat detection, the method comprising the following steps: S1, aligning the X-axis of the coordinate system by measuring the reference end face with a three-coordinate measuring machine, and simultaneously locating the X-coordinate position of the origin of the coordinate system; S2, determining the Y and Z coordinate positions of the origin of the coordinate system by measuring the reference circle with a three-coordinate measuring machine, and obtaining the coordinate system; S3, obtaining the theoretical value coordinates and the measured value coordinates of the measuring point; S4, correcting the coordinate system according to the difference between the measured value coordinates and the theoretical value coordinates of the measuring point, and obtaining the adjusted coordinate system; S5, judging whether the difference between the measured value coordinates and the theoretical value coordinates of the measuring point meets the allowable error value, if not, returning to step S4, if satisfied, outputting the adjusted coordinate system.
[0011] According to an embodiment of the present invention, step S3 includes: 31 , define the theoretical value coordinates of the measuring point; S 32 , use a three-coordinate measuring machine to estimate the position of the measuring point, and obtain the actual measured value coordinates of the measuring point according to the coordinate system.
[0012] According to an embodiment of the present invention, step S4 includes: 41 , controlling the current coordinate system to adjust, rotating the angle, and obtaining the adjusted coordinate system; S 42 , according to the adjusted coordinate system, automatically run the three-coordinate measuring machine to measure the points, and measure again to obtain the actual measured value coordinates of the measuring points.
[0013] According to an embodiment of the present invention, the theoretical coordinates of the measuring point in step S3 are LP=[x yz], and the measured coordinates of the measuring point are CP n =[u n v n w n ], wherein x represents the theoretical value x coordinate of the measuring point, y represents the theoretical value y coordinate of the measuring point, and z represents the theoretical value z coordinate of the measuring point; u n represents the measured value x coordinate of the nth measurement of the measuring point, v n represents the measured value y coordinate of the nth measurement of the measuring point, w n Represents the measured value z coordinate of the nth measurement of the measuring point.
[0014] According to one embodiment of the present invention, the step S 41 The rotation angle is the coordinate system correction angle θ n ,θ n The calculation formula is: f = min ((v n ·cos(θ n )-w n ·sin(θ n )-y) 2 +(v n ·sin(θ n )+w n ·cos(θ n )-z) 2 +(u n -x) 2 ), where f is the least squares equation, θ n is the nth correction angle of the coordinate system; x represents the theoretical x-coordinate of the measuring point, y represents the theoretical y-coordinate of the measuring point, and z represents the theoretical z-coordinate of the measuring point; u n represents the measured value x coordinate of the nth measurement of the measuring point, v n represents the measured value y coordinate of the nth measurement of the measuring point, w n Represents the measured value z coordinate of the nth measurement of the measuring point.
[0015] According to one embodiment of the present invention, the calculation formula of the error allowable value in step S5 is: Wherein, Δ is the allowable error value; x represents the theoretical value x coordinate of the measuring point, y represents the theoretical value y coordinate of the measuring point, and z represents the theoretical value z coordinate of the measuring point; u n represents the measured value x coordinate of the nth measurement of the measuring point, v n represents the measured value y coordinate of the nth measurement of the measuring point, w n Represents the measured value z coordinate of the nth measurement of the measuring point.
[0016] The positive and progressive effects of the present invention are:
[0017] The method for establishing a throat detection reference coordinate system proposed in the present invention can avoid selecting the Z-axis of the hole feature positioning coordinate system. By selecting the measuring point on the throat window, the probe of the three-dimensional coordinate measuring machine is controlled to continuously measure and correct the selected measuring point so that the measurement result basically coincides with the theoretical value to realize the establishment of the coordinate system. This method is not only applicable to structures with special featureless hole positioning Z-axis, but also applicable to structures with special positioning holes. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The above and other features, properties and advantages of the present invention will become more apparent through the following description in conjunction with the accompanying drawings and embodiments, in which the same reference numerals always represent the same features, wherein:
[0019] Figure 1 Schematic diagram of the guide structure.
[0020] Figure 2 Schematic diagram of the structure for detection without positioning features.
[0021] Figure 3 It is a schematic diagram of establishing a coordinate system without feature points in the method for establishing a reference coordinate system for laryngeal passage detection of the present invention.
[0022] Figure 4 It is a schematic diagram of the flow of the method for establishing a throat detection reference coordinate system according to the present invention. DETAILED DESCRIPTION
[0023] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.
[0024] Embodiments of the present invention will now be described in detail with reference to the accompanying drawings. Reference will now be made in detail to preferred embodiments of the present invention, examples of which are shown in the accompanying drawings. Wherever possible, the same reference numerals will be used throughout the drawings to represent the same or similar parts.
[0025] Furthermore, although the terms used in the present invention are selected from well-known and commonly used terms, some terms mentioned in the present invention specification may be selected by the applicant at his or her discretion, and their detailed meanings are explained in the relevant parts of the description of this document.
[0026] Furthermore, it is required that the present invention be understood not only by the actual terms used but also by the meanings connoted by each term.
[0027] In the field of engines, the throat area of engine blades is an important parameter for engine assembly and debugging, and the measurement of throat area is the key to blade assembly. Figure 1 The blade passage shown is a spatial curved surface passage formed by the upper edge plate 1 , the lower edge plate 2 and the blade body profiles of every two guide vanes 3 .
[0028] like Figure 2 As shown, the detection structure has no positioning features similar to positioning feature holes. For the detection structure, the present invention provides a method for establishing a throat detection reference coordinate system, the method comprising the following steps:
[0029] Step S1, measuring the reference end surface by a three-dimensional coordinate measuring machine to align the X-axis of the coordinate system and locate the X-coordinate position of the origin of the coordinate system;
[0030] Step S2, measuring the reference circle by a three-coordinate measuring machine to determine the Y and Z coordinate positions of the origin of the coordinate system, and obtaining the coordinate system;
[0031] Step S3, obtaining the theoretical value coordinates and the measured value coordinates of the measuring point;
[0032] Step S4, correcting the coordinate system according to the difference between the measured value coordinates and the theoretical value coordinates of the measuring point to obtain an adjusted coordinate system;
[0033] Step S5, determine whether the difference between the measured value coordinates and the theoretical value coordinates of the measuring point meets the allowable error value. If not, return to step S4; if so, output the adjusted coordinate system.
[0034] The output adjusted coordinate system is then put into practical application.
[0035] The step S3 preferably includes:
[0036] Step S 31 , define the theoretical value coordinates of the measuring point;
[0037] Step S 32 , use a three-coordinate measuring machine to estimate the position of the measuring point, and obtain the actual measured value coordinates of the measuring point according to the coordinate system.
[0038] The step S4 preferably includes:
[0039] Step S 41 , controlling the current coordinate system to adjust, rotating the angle, and obtaining the adjusted coordinate system;
[0040] Step S 42 , according to the adjusted coordinate system, automatically run the three-coordinate measuring machine to measure the points, and measure again to obtain the actual measured value coordinates of the measuring points.
[0041] In step S3, the measuring point can be defined as P, and the theoretical coordinates of the measuring point P are
[0042] LP = [xyz]
[0043] The measured value coordinates of the first measurement of the measuring point P are
[0044] CP n =[u n v n w n ]
[0045] Wherein, x represents the theoretical value x coordinate of the measuring point, y represents the theoretical value y coordinate of the measuring point, and z represents the theoretical value z coordinate of the measuring point; u nrepresents the measured value x coordinate of the nth measurement of the measuring point, v n represents the measured value y coordinate of the nth measurement of the measuring point, w n Represents the measured value z coordinate of the nth measurement of the measuring point.
[0046] Step S 41 The rotation angle can be used to correct the coordinate system angle θ n ,θ n The calculation formula is:
[0047] f=min((v n ·cos(θ n )-w n ·sin(θ n )-y) 2 +(v n ·sin(θ n )+w n ·cos(θ n )-z) 2 +(u n -x) 2 );
[0048] Where f is the least squares equation, θ n is the nth correction angle of the coordinate system; x represents the theoretical x-coordinate of the measuring point, y represents the theoretical y-coordinate of the measuring point, and z represents the theoretical z-coordinate of the measuring point; u n represents the measured value x coordinate of the nth measurement of the measuring point, v n represents the measured value y coordinate of the nth measurement of the measuring point, w n Represents the measured value z coordinate of the nth measurement of the measuring point.
[0049] The calculation formula of the error allowable value in step S5 can be:
[0050]
[0051] Where Δ is the allowable error value; x represents the theoretical x-coordinate of the measuring point P, y represents the theoretical y-coordinate of the measuring point P, and z represents the theoretical z-coordinate of the measuring point P; u n represents the measured value x coordinate of the nth measurement of the measuring point P, v n represents the measured value y coordinate of the nth measurement of the measuring point P, w n It represents the measured value z coordinate of the nth measurement of measuring point P.
[0052] The measurement process of a preferred implementation of the method for establishing a reference coordinate system for throat detection is as follows:
[0053] The first step, such as Figure 3 As shown, the reference end face is measured by a three-dimensional coordinate measuring machine, and the X-axis of the coordinate system is aligned using points A, B and C, while the X-coordinate position of the origin of the coordinate system is located;
[0054] The second step is, Figure 3 As shown, the reference circle is measured by a three-dimensional coordinate measuring machine, and the Y and Z coordinate positions of the origin of the coordinate system are determined using points D, E and F;
[0055] The third step is to use a three-dimensional coordinate measuring machine to estimate Figure 3 The position of the measuring point P is shown in the figure.
[0056] The fourth step is to define the theoretical coordinates LP of point P and the actual measured coordinates CP1 of point P.
[0057] LP=[xyz] (1)
[0058] CP1=[u1 v1 w1] (2)
[0059] In the formula, x represents the theoretical x-coordinate of the measuring point P, y represents the theoretical y-coordinate of the measuring point P, and z represents the theoretical z-coordinate of the measuring point P; u1 represents the actual x-coordinate of the first measurement of the measuring point P, v1 represents the actual y-coordinate of the first measurement of the measuring point P, and w1 represents the actual z-coordinate of the first measurement of the measuring point P.
[0060] Step 5. According to the above results, control the current coordinate system adjustment. The calculation formula of the rotation angle is as follows;
[0061] f=min((v1·cos(θ1)-w1·sin(θ1)-y) 2 +(v1·sin(θ1)+w1·cos(θ1)-z) 2 +(u1-x) 2 )(3)
[0062] In the formula, f is the least squares equation, θ1 is the first correction angle of the coordinate system; x represents the theoretical x-coordinate of the measuring point P, y represents the theoretical y-coordinate of the measuring point P, and z represents the theoretical z-coordinate of the measuring point P; u1 represents the actual x-coordinate of the first measurement of the measuring point P, v1 represents the actual y-coordinate of the first measurement of the measuring point P, and w1 represents the actual z-coordinate of the first measurement of the measuring point P.
[0063] Step 6: Automatically run the three-dimensional coordinate measuring machine to measure the new measuring point CP2, which is recorded as
[0064] CP2=[u2 v2 w2] (4)
[0065] In the formula, u2 represents the x-coordinate of the actual value of the second measurement of the measuring point P, v2 represents the y-coordinate of the actual value of the second measurement of the measuring point P, and w2 represents the z-coordinate of the actual value of the second measurement of the measuring point P.
[0066] Step 7. According to the above results, control the current coordinate system adjustment. The calculation formula of the rotation angle is as follows;
[0067] f=min((v2·cos(θ2)-w2·sin(θ2)-y) 2 +(v2·sin(θ2)+w2·cos(θ2)-z) 2 +(u2-x) 2 )(5)
[0068] In the formula, f is the least squares equation, θ2 is the second coordinate system correction angle; x represents the theoretical x-coordinate of the measuring point P, y represents the theoretical y-coordinate of the measuring point P, and z represents the theoretical z-coordinate of the measuring point P; u2 represents the actual x-coordinate of the second measurement of the measuring point P, v2 represents the actual y-coordinate of the second measurement of the measuring point P, and w2 represents the actual z-coordinate of the second measurement of the measuring point P.
[0069] Step 8: Continue to repeat the measurement until the following conditions are met
[0070]
[0071] Where Δ is the allowable error value; x represents the theoretical x-coordinate of the measuring point P, y represents the theoretical y-coordinate of the measuring point P, and z represents the theoretical z-coordinate of the measuring point P; u n represents the measured value x coordinate of the nth measurement of the measuring point P, v n represents the measured value y coordinate of the nth measurement of the measuring point P, w n It represents the measured value z coordinate of the nth measurement of measuring point P.
[0072] The experimental data examples of the method for establishing the throat detection reference coordinate system in the above preferred embodiment are as follows:
[0073] The measuring point P defines the Z-axis direction of the coordinate axis. The theoretical value of point P is [2.3 10.5 248.2], and the allowable error value is set to 0.01mm.
[0074] According to the method of the preferred embodiment, the measured value coordinates of the measuring point P are [2.581 11.903249.336], and the execution error is 1.8270 mm. The correction angle is 0.31° calculated by formula (3), and the coordinate system is corrected according to the correction angle.
[0075] The theoretical value of point P is measured according to the corrected coordinate system, and the actual measured value of the measuring point is [2.301 10.765248.981]. The execution error is 0.8621 mm. The correction angle is 0.08° calculated by formula (3), and the coordinate system is corrected according to the correction angle.
[0076] The theoretical value of point P is measured according to the corrected coordinate system, and the actual measured value of the measuring point is [2.299 10.503248.205]. The execution error at this time is 0.0059mm, which meets the accuracy requirements.
[0077] The present invention proposes a method for establishing a throat detection reference coordinate system. The method can avoid selecting the Z axis of the hole feature positioning coordinate system. By selecting the measuring point on the throat window, the probe of the three-dimensional coordinate measuring machine is controlled to continuously measure and correct the selected measuring point, so that the measurement result is basically consistent with the theoretical value, thereby realizing the establishment of the coordinate system. The method is not only applicable to the structure with special featureless hole positioning Z axis, but also applicable to the structure with special positioning hole.
[0078] The method for establishing a throat detection reference coordinate system of the present invention uses the characteristic points on the throat window of the guide as positioning points, corrects the measured points through cyclic iteration, corrects the coordinate system through the results of the measurement process, and uses posture transformation to process data. The method solves the problem of establishing a coordinate system for throat area measurement of a three-coordinate measuring machine, solves the problem of detecting no characteristic holes in three-coordinate throat area measurement, and solves the problem of wider application of three-coordinate measuring machines in throat area measurement.
[0079] In summary, the method for establishing a laryngeal passage detection reference coordinate system of the present invention has the following beneficial effects:
[0080] 1. Realize the featureless positioning pore throat area detection.
[0081] 2. The accuracy of three-coordinate throat area detection has been improved.
[0082] 3. A new method for throat area analysis is provided.
[0083] 4. Improved engine inspection quality.
[0084] 5. The one-time assembly qualification rate of the engine has been improved.
[0085] Although the specific embodiments of the present invention are described above, it should be understood by those skilled in the art that these are only examples, and the protection scope of the present invention is defined by the appended claims. Those skilled in the art may make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but these changes and modifications all fall within the protection scope of the present invention.
Claims
1. A method for establishing a throat detection reference coordinate system, characterized in that: The method comprises the following steps: S1. Use a three-coordinate measuring machine to measure the reference end face to align the X-axis of the coordinate system and locate the X-coordinate position of the origin of the coordinate system; S2, measuring the reference circle by a three-coordinate measuring machine to determine the Y and Z coordinate positions of the origin of the coordinate system and obtain the coordinate system; S3, obtaining the theoretical value coordinates and the measured value coordinates of the measuring point; S4, correcting the coordinate system according to the difference between the measured value coordinates of the measuring point and the theoretical value coordinates to obtain an adjusted coordinate system; S5. Determine whether the difference between the actual value coordinates of the measuring point and the theoretical value coordinates meets the allowable error value. If not, return to step S4. If so, output the adjusted coordinate system.
2. The method for establishing a laryngeal passage detection reference coordinate system according to claim 1, characterized in that: The step S3 includes: S 31 , define the theoretical value coordinates of the measuring point; S 32 , use a three-coordinate measuring machine to estimate the position of the measuring point, and obtain the actual measured value coordinates of the measuring point according to the coordinate system.
3. The method for establishing a laryngeal passage detection reference coordinate system according to claim 2, characterized in that: The step S4 includes: S 41 , controlling the current coordinate system to adjust, rotating the angle, and obtaining the adjusted coordinate system; S 42 , according to the adjusted coordinate system, automatically run the three-coordinate measuring machine to measure the points, and measure again to obtain the actual measured value coordinates of the measuring points.
4. The method for establishing a laryngeal passage detection reference coordinate system according to claim 2, characterized in that: The theoretical coordinates of the measuring point in step S3 are LP=[xyz], and the actual coordinates of the measuring point are CP n =[u n v n w n ], Wherein, x represents the theoretical value x coordinate of the measuring point, y represents the theoretical value y coordinate of the measuring point, and z represents the theoretical value z coordinate of the measuring point; u n represents the measured value x coordinate of the nth measurement of the measuring point, v n represents the measured value y coordinate of the nth measurement of the measuring point, w n Represents the measured value z coordinate of the nth measurement of the measuring point.
5. The method for establishing a laryngeal passage detection reference coordinate system according to claim 3, characterized in that: The step S 41 The rotation angle is the coordinate system correction angle θ n ,θ n The calculation formula is: f=min((v n ·cos(θ n )-w n ·sin(θ n )-y) 2 +(v n ·sin(θ n )+w n ·cos(θ n )-z) 2 +(u n -x) 2 ); Where f is the least squares equation, θ n is the nth correction angle of the coordinate system; x represents the theoretical x-coordinate of the measuring point, y represents the theoretical y-coordinate of the measuring point, and z represents the theoretical z-coordinate of the measuring point; u n represents the measured value x coordinate of the nth measurement of the measuring point, v n represents the measured value y coordinate of the nth measurement of the measuring point, w n Represents the measured value z coordinate of the nth measurement of the measuring point.
6. The method for establishing a laryngeal passage detection reference coordinate system according to claim 1, characterized in that: The calculation formula of the error allowable value in step S5 is: Wherein, Δ is the allowable error value; x represents the theoretical value x coordinate of the measuring point, y represents the theoretical value y coordinate of the measuring point, and z represents the theoretical value z coordinate of the measuring point; u n represents the measured value x coordinate of the nth measurement of the measuring point, v n represents the measured value y coordinate of the nth measurement of the measuring point, w n Represents the measured value z coordinate of the nth measurement of the measuring point.