Automatic laser alignment method and device for aero-engine case

Abstract

The invention relates to the field of aeronautical manufacturing automatic machining, and discloses an automatic laser alignment method and device for an aero-engine case. According to the method, coordinate values of a plurality of scanning points on a reference circle of an aero-engine casing with a cylindrical thin-wall structure in an alignment coordinate system are utilized, and a least square method is adopted for optimization fitting to obtain a circle center coordinate of the reference circle, so that center alignment of the casing is realized; angular alignment is completed by obtaining the angular value of the angular hole in the cartridge receiver, and then the purpose of automatically aligning the center of the cartridge receiver and the angular direction of the cartridge receiver is achieved.

Description

Technical Field

[0001] The present invention relates to the field of automated machining in aviation manufacturing, and discloses a method and device for automatically laser-aligning an aero-engine casing. Background Art

[0002] Aero-engines are known as the "crown jewels" of modern industry. Aero parts are of high value and have a long research and development cycle. At present, major mainframe manufacturers in the industry are introducing intelligent production lines for automated machining. However, there are basically two alignment methods for parts entering the line: one is manual alignment, which has the disadvantages of long alignment time, poor alignment effect, and low automation level; the other is to customize special positioning tooling, but it has the disadvantages of high cost and poor versatility. And the commonly used alignment devices in the industry are all for aligning the center of the casing and cannot align the angular orientation of the angular holes of the aero-engine casing. Summary of the Invention

[0003] The purpose of the present invention is to provide a method and device for automatically laser-aligning an aero-engine casing, which can achieve the purpose of quickly aligning the center of the casing and the angular orientation of the casing.

[0004] In order to achieve the above technical effects, the technical solution adopted by the present invention is:

[0005] A method for automatically laser-aligning an aero-engine casing, comprising:

[0006] Place one end face of the aero-engine casing with a cylindrical thin-walled structure on a rotating working platform, the upper surface of the rotating working platform is a planar structure, the rotation axis of the rotating working platform is perpendicular to the upper surface, and adjust the rotating working platform so that the upper surface is in a horizontal state;

[0007] Taking the rotation center of the upper surface of the rotating working platform as the origin O, two mutually perpendicular straight lines on the upper surface passing through the origin are the X-axis and the Y-axis respectively, and the straight line passing through the origin and perpendicular to the upper surface of the rotating working platform is the Z-axis, to establish an alignment coordinate system;

[0008] Obtain the coordinate values of multiple scanning points on the reference circle of the casing relative to the alignment coordinate system, and optimize and fit according to the X-axis coordinates and Y-axis coordinate values of the multiple scanning points by using the least squares method to obtain the center coordinate of the reference circle;

[0009] Move the casing so that the center of the reference circle of the casing coincides with the origin of the alignment coordinate system to complete the alignment of the center of the casing;

[0010] Emit a laser beam along the X-axis towards the casing wall surface, adjust the height of the laser beam to be flush with the angular hole on the casing, and set a laser receiver at a position directly opposite to the laser beam; the laser receiver and the laser beam light source are respectively located on both sides of the casing wall surface;

[0011] Rotate the rotary working platform at least two turns, obtain two laser mutation signals generated by the laser receiver when the angular holes of the casing pass through the laser beam during each turn, and obtain the rotation angle of the rotary table when the two laser mutation signals are generated;

[0012] According to the rotation angle of the rotary table when two laser mutation signals are generated during each turn, analyze and obtain the angular value of the angular hole in the current turn, determine the angular value of the last turn number whose difference from the angular value of the previous turn is less than the preset threshold as the angular value of the angular hole, and rotate the center point of the angular hole of the casing to the XOZ plane according to the angular value of the angular hole.

[0013] Further, rotate the rotary working platform with the Z-axis of the alignment coordinate system as the central axis. During the rotation process, use a laser rangefinder to scan the reference circle of the casing, and analyze and obtain the coordinate values of multiple scan points on the reference circle of the casing in the alignment coordinate system according to the scanning results of the laser rangefinder.

[0014] Further, the method for optimizing and fitting the center coordinate of the reference circle by using the least squares method according to the X-axis coordinates and Y-axis coordinate values of multiple scan points on the reference circle of the casing includes:

[0015] Construct a fitting variance analysis function between the distance from the scan point to the Z-axis and the fitting radius of the reference circle where E is the fitting variance between the distance from the scan point to the Z-axis and the fitting radius of the reference circle, x i is the coordinate value of the i-th scan point on the X-axis, y i is the coordinate value of the i-th scan point on the Y-axis, n is the number of scan points, A and B are coefficients, and C is a constant;

[0016] Substitute the X-axis coordinate and Y-axis coordinate values of each scan point into the fitting variance analysis function, and obtain the values of A, B, and C when the fitting variance is the smallest through least squares fitting;

[0017] According to the fitted A and B values, determine that the center coordinate of the reference circle in the XOY plane is

[0018]

[0019] Further, according to the rotation angle of the rotary table when two laser mutation signals are generated during each turn, use Analyze and obtain the angular value θ of the angular hole in the current turn j , where α j is the rotation angle value of the rotary working platform when the first laser mutation signal is generated during the j-th turn, β j$\theta_j$ is the rotation angle value of the rotary work platform when the second laser mutation signal is generated in the $j$-th rotation, and $m$ is the total number of rotations currently made.

[0020] Further, the preset threshold is 0.0001°.

[0021] To achieve the above technical effects, the present invention also provides an automatic laser alignment device for an aero-engine casing, which is used to implement the automatic laser alignment method for an aero-engine casing, and includes:

[0022] A rotary work platform, the upper surface of the rotary work platform is a planar structure, and the upper surface is used to place the aero-engine casing, and the rotation axis of the rotary work platform is perpendicular to the upper surface;

[0023] A coordinate system construction module, which is used to establish an alignment coordinate system with the rotation center of the upper surface of the rotary work platform as the origin, two mutually perpendicular straight lines passing through the origin on the upper surface as the X-axis and the Y-axis respectively, and a straight line passing through the origin and perpendicular to the upper surface of the rotary work platform as the Z-axis;

[0024] A data acquisition module, which is used to obtain the coordinate values of multiple scanning points on the reference circle of the aero-engine casing with a cylindrical thin-walled structure placed on the rotary work platform relative to the alignment coordinate system;

[0025] A center coordinate analysis module, which is used to optimize and fit the center coordinates of the reference circle by using the least square method according to the X-axis coordinates and Y-axis coordinate values of multiple scanning points on the reference circle of the casing;

[0026] A center alignment analysis module, which is used to analyze the moving distance and direction of the casing according to the obtained center coordinates of the reference circle, so that the center of the reference circle of the casing coincides with the origin of the alignment coordinate system to complete the center alignment of the casing;

[0027] An angular hole alignment analysis module, which is used to analyze the rotation angle of the casing after the center alignment is completed according to the angular value of the angular hole relative to the X-axis, so as to rotate the center point of the angular hole of the casing to the XOZ plane.

[0028] Further, in the center coordinate analysis module, the method for optimizing and fitting the center coordinates of the reference circle by using the least square method includes:

[0029] Construct a fitting variance analysis function between the distance from the scanning point to the Z-axis and the fitting radius of the reference circle where $E$ is the fitting variance between the distance from the scanning point to the Z-axis and the fitting radius of the reference circle, $x$ i is the coordinate value of the $i$-th scanning point on the X-axis, $y$ iis the coordinate value of the i-th scanning point on the Y-axis, n is the number of scanning points, A and B are coefficients, and C is a constant;

[0030] Substitute the X-axis coordinates and Y-axis coordinate values of each scanning point into the fitting variance analysis function, and obtain the values of A, B, and C when the fitting variance is minimized by least squares fitting;

[0031] According to the fitted A and B values, determine that the center coordinates of the reference circle in the XOY plane are

[0032]

[0033] Further, in the angular hole alignment analysis module, the method for obtaining the angular value of the angular hole relative to the X-axis includes:

[0034] Emit a laser beam along the X-axis towards the casing wall surface, adjust the height of the laser beam to be flush with the angular hole on the casing, and set a laser receiver at a position directly opposite the laser beam; the laser receiver and the laser beam light source are located on both sides of the casing wall surface;

[0035] Rotate the rotary work platform at least two circles, obtain two laser mutation signals generated by the laser receiver when the angular hole of the casing passes through the laser beam during each rotation, and obtain the rotation angle of the rotary worktable when the two laser mutation signals are generated;

[0036] According to the rotation angle of the rotary worktable when two laser mutation signals are generated during each rotation, analyze and obtain the angular value of the angular hole at the current rotation, and determine the angular value of the last rotation whose difference from the angular value of the previous rotation is less than a preset threshold as the angular value of the angular hole.

[0037] Further, according to the rotation angle of the rotary worktable when two laser mutation signals are generated during each rotation, use Analyze and obtain the angular value θ of the angular hole at the current rotation j , where α j is the rotation angle value of the rotary work platform when the first laser mutation signal is generated during the j-th rotation, β j is the rotation angle value of the rotary work platform when the second laser mutation signal is generated during the j-th rotation, and m is the total number of current rotations.

[0038] Further, it also includes an alignment platform. The bottom of the alignment platform is fixed. A zero-point positioning system is provided on the alignment platform. The zero-point positioning system includes a plurality of lifting rods installed on the upper surface of the alignment platform. The rotary work platform is installed on the top of the plurality of lifting rods. The plurality of lifting rods are used to cooperate and adjust to make the upper surface of the rotary work platform horizontal.

[0039] Compared with the prior art, the beneficial effects of the present invention are as follows: By constructing an alignment coordinate system based on the upper surface and the rotation center of the rotary worktable, and using the coordinate values of multiple scanning points on the reference circle of the aero-engine casing with a cylindrical thin-walled structure in the alignment coordinate system, the center coordinates of the reference circle are obtained by optimizing and fitting using the least square method, realizing the center alignment of the casing; By obtaining the angular values of the angular holes on the casing, angular alignment is completed, and thus the purpose of quickly and accurately aligning the center and the angular direction of the casing is achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 is a flowchart of the automatic laser alignment method for an aero-engine casing in the embodiment;

[0041] Figure 2 is a structural block diagram of the automatic laser alignment device for an aero-engine casing in the embodiment;

[0042] Figure 3 is a schematic installation structure diagram of the rotary work platform on the alignment platform in the embodiment;

[0043] Among them, 1. Rotary work platform; 2. Coordinate system construction module; 3. Data acquisition module; 4. Center coordinate analysis module; 5. Center alignment analysis module; 6. Angular hole alignment analysis module; 7. Laser receiver; 8. Light source; 9. Alignment platform; 10. Zero-point positioning system. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0044] The present invention will be further described in detail below in conjunction with the embodiments and the drawings. However, it should not be understood that the scope of the above-mentioned subject matter of the present invention is limited to the following embodiments. Any technology implemented based on the content of the present invention belongs to the scope of the present invention.

[0045] Embodiment 1

[0046] See Figures 1-3 , an automatic laser alignment method for an aero-engine casing, including:

[0047] Place one end face of the aero-engine casing with a cylindrical thin-walled structure on the rotary work platform 1. The upper surface of the rotary work platform 1 is a planar structure, and the rotation axis of the rotary work platform 1 is perpendicular to the upper surface. Adjust the rotary work platform 1 to make the upper surface in a horizontal state;

[0048] Taking the rotation center of the upper surface of the rotary work platform 1 as the origin O, two mutually perpendicular straight lines passing through the origin on the upper surface are the X-axis and the Y-axis respectively, and the straight line passing through the origin and perpendicular to the upper surface of the rotary work platform 1 is the Z-axis, to establish an alignment coordinate system;

[0049] Obtain the coordinate values of multiple scanning points on the reference circle of the casing relative to the alignment coordinate system, and optimize and fit the center coordinates of the reference circle by using the least squares method according to the X-axis coordinates and Y-axis coordinate values of the multiple scanning points;

[0050] Move the casing so that the center of the reference circle of the casing coincides with the origin of the alignment coordinate system to complete the alignment of the casing center;

[0051] Emit a laser beam along the X-axis towards the casing wall surface, adjust the height of the laser beam to be flush with the angular hole on the casing, and set a laser receiver 7 at the position directly facing the laser beam; the laser receiver 7 and the laser beam light source 8 are respectively located on both sides of the casing wall surface;

[0052] Rotate the rotary work platform 1 at least two turns, obtain two laser mutation signals generated by the laser receiver 7 when the angular hole of the casing passes through the laser beam during each turn, and obtain the rotation angle of the rotary worktable when the two laser mutation signals are generated;

[0053] According to the rotation angle of the rotary worktable when two laser mutation signals are generated during each turn, analyze and obtain the angular value of the angular hole at the current rotation turn, determine the angular value of the last rotation turn whose difference from the angular value of the previous turn is less than the preset threshold as the angular value of the angular hole, and rotate the center point of the angular hole of the casing to the XOZ plane according to the angular value of the angular hole.

[0054] In this embodiment, by constructing an alignment coordinate system based on the upper surface and the rotation center of the rotary work platform, using the coordinate values of multiple scanning points on the reference circle of the casing of an aero-engine with a cylindrical thin-walled structure in the alignment coordinate system, and optimizing and fitting the center coordinates of the reference circle by using the least squares method, the alignment of the casing center is realized; by obtaining the angular value of the angular hole on the casing, the angular alignment is completed, so as to achieve the purpose of quickly and accurately aligning the center and the angle of the casing.

[0055] Based on the same inventive concept, this embodiment also provides an automatic laser alignment device for an aero-engine casing, which is used to implement the automatic laser alignment method for an aero-engine casing, and includes:

[0056] A rotary work platform 1, the upper surface of the rotary work platform 1 is a flat structure, the upper surface is used to place the aero-engine casing, and the rotation axis of the rotary work platform 1 is perpendicular to the upper surface;

[0057] A coordinate system construction module 2, which is used to establish an alignment coordinate system with the rotation center of the upper surface of the rotary work platform 1 as the origin, two mutually perpendicular straight lines passing through the origin on the upper surface as the X-axis and the Y-axis respectively, and a straight line passing through the origin and perpendicular to the upper surface of the rotary work platform 1 as the Z-axis;

[0058] The data acquisition module 3 is used to obtain the coordinate values of multiple scanning points on the reference circle of the cylindrical thin-walled structure of the aero-engine casing placed on the rotary working platform 1 relative to the alignment coordinate system;

[0059] The center coordinate analysis module 4 is used to optimize and fit the center coordinates of the reference circle by using the least square method according to the X-axis coordinates and Y-axis coordinate values of multiple scanning points on the reference circle of the casing;

[0060] The center alignment analysis module 5 is used to analyze and obtain the moving distance and direction of the casing according to the obtained center coordinates of the reference circle, so that the center of the reference circle of the casing coincides with the origin of the alignment coordinate system, and the center alignment of the casing is completed;

[0061] The angular hole alignment analysis module 6 is used to analyze and obtain the rotation angle of the casing after the center alignment is completed according to the angular value of the angular hole relative to the X-axis, so as to rotate the center point of the angular hole of the casing to the XOZ plane.

[0062] Embodiment 2

[0063] See Figure 1 and Figure 3 This embodiment takes the alignment process of a certain type of cylindrical thin-walled structure aero-engine casing as an example to elaborate in detail the process of the automatic laser alignment method for aero-engine casings of the present invention, which specifically includes the following steps:

[0064] Step 1: Place one end face of the cylindrical thin-walled structure aero-engine casing on the rotary working platform 1. The upper surface of the rotary working platform 1 is a flat structure, and the rotation axis of the rotary working platform 1 is perpendicular to the upper surface. Adjust the rotary working platform 1 to make the upper surface in a horizontal state;

[0065] In this embodiment, the rotary working platform 1 is arranged on the alignment platform 9. The bottom of the alignment platform 9 is fixed, and a zero-point positioning system 10 is arranged on the alignment platform 9. The zero-point positioning system 10 includes a plurality of lifting rods installed on the upper surface of the alignment platform 9. The rotary working platform 1 is installed on the tops of the plurality of lifting rods, and the plurality of lifting rods are used to cooperate and adjust to make the upper surface of the rotary working platform 1 in a horizontal state.

[0066] Step 2: Take the rotation center of the upper surface of the rotary working platform 1 as the origin O, the two mutually perpendicular lines passing through the origin on the upper surface are the X-axis and the Y-axis respectively, and the line passing through the origin and perpendicular to the upper surface of the rotary working platform 1 is the Z-axis to establish an alignment coordinate system;

[0067] Step 3: Obtain the coordinate values of multiple scanning points on the reference circle of the casing relative to the alignment coordinate system, and optimize and fit the center coordinates of the reference circle by using the least squares method according to the X-axis coordinates and Y-axis coordinate values of the multiple scanning points;

[0068] In this embodiment, first, rotate the rotary work platform 1 with the Z-axis of the alignment coordinate system as the central axis. During the rotation process, scan the reference circle of the casing by using a laser rangefinder, and analyze the scanning results of the laser rangefinder to obtain the coordinate values of multiple scanning points on the reference circle of the casing in the alignment coordinate system;

[0069] Secondly, construct an analysis function of the fitting variance between the distance from the scanning point to the Z-axis and the fitting radius of the reference circle where E is the fitting variance between the distance from the scanning point to the Z-axis and the fitting radius of the reference circle, x i is the coordinate value of the i-th scanning point on the X-axis, y i is the coordinate value of the i-th scanning point on the Y-axis, n is the number of scanning points, A and B are coefficients, and C is a constant;

[0070] Then, substitute the X-axis coordinate and Y-axis coordinate values of each scanning point into the fitting variance analysis function, and obtain the values of A, B, and C when the fitting variance is the smallest by using the least squares method for fitting;

[0071] Finally, according to the fitted A and B values, the center coordinates of the reference circle in the XOY plane can be determined as

[0072] Step 4: Move the casing to make the center of the reference circle of the casing coincide with the origin of the alignment coordinate system to complete the alignment of the casing center;

[0073] In this embodiment, then move the central axis of the casing to the Z-axis of the alignment coordinate system through the robotic arm to move the central axis of the casing to the center of the work platform to achieve the alignment effect. After aligning the casing center, fix it with a pressing plate.

[0074] Step 5: Emit a laser beam along the X-axis towards the wall surface of the casing, adjust the height of the laser beam to be flush with the angular hole on the casing, and set a laser receiver 7 at a position directly opposite to the laser beam; the laser receiver 7 and the laser beam light source 8 are respectively located on both sides of the casing wall surface;

[0075] Step 6: Rotate the rotary work platform 1 at least two turns, obtain two laser mutation signals generated by the laser receiver 7 when the angular hole of the casing passes through the laser beam during each turn, and obtain the rotation angle of the rotary worktable when the two laser mutation signals are generated;

[0076] For example, during the rotation of the casing after centering in this embodiment, when passing through the X-axis at the edge position on one side of the angular hole, the rotation angle value of the current rotary table is recorded at the moment when the laser receiver 7 changes from having no laser signal to having a laser signal; then during the continuous rotation process, the rotation angle value of the current rotary table is recorded at the moment when the laser receiver 7 changes from having a laser signal to having no laser signal, and then the middle value of the two rotation angle values is taken, which is the angular value of the angular hole obtained during one rotation. Therefore, the angular value θ of the angular hole during the current rotation can be analyzed and obtained j , where α j is the rotation angle value of the rotary table 1 when the first laser mutation signal occurs during the j-th rotation, β j is the rotation angle value of the rotary table 1 when the second laser mutation signal occurs during the j-th rotation, and m is the total number of rotations in the current rotation.

[0077] Step 7: Analyze and obtain the angular value of the angular hole during the current rotation according to the rotation angles of the rotary table when two laser mutation signals are generated during each rotation, and determine the angular value of the last rotation number whose difference from the angular value of the previous rotation is less than the preset threshold as the angular value of the angular hole. Rotate the center point of the angular hole of the casing to the XOZ plane according to the angular value of the angular hole; in this embodiment, the preset threshold is 0.0001°.

[0078] The above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An automatic laser alignment method for an aeroengine casing, characterized in that, Including: Place one end face of the cylindrical thin-walled structure of the aero-engine casing on the rotating working platform. The upper surface of the rotating working platform is a planar structure, and the rotation axis of the rotating working platform is perpendicular to the upper surface. Adjust the rotating working platform so that the upper surface is in a horizontal state; Taking the rotation center of the upper surface of the rotating working platform as the origin O, two mutually perpendicular straight lines passing through the origin on the upper surface are the X-axis and the Y-axis respectively, and the straight line passing through the origin and perpendicular to the upper surface of the rotating working platform is the Z-axis, to establish an alignment coordinate system; Obtain the coordinate values of multiple scanning points on the reference circle of the casing relative to the alignment coordinate system, and optimize and fit the center coordinates of the reference circle by using the least square method according to the X-axis coordinates and Y-axis coordinate values of the multiple scanning points; Move the casing so that the center of the reference circle of the casing coincides with the origin of the alignment coordinate system to complete the alignment of the casing center; Emit a laser beam along the X-axis towards the casing wall surface, adjust the height of the laser beam to be flush with the angular hole on the casing, and set a laser receiver at the position directly facing the laser beam; the laser receiver and the laser beam light source are respectively located on both sides of the casing wall surface; Rotate the rotating working platform at least two circles, obtain two laser mutation signals generated by the laser receiver when the angular hole of the casing passes through the laser beam during each rotation, and obtain the rotation angle of the rotating working platform when the two laser mutation signals are generated; According to the rotation angle of the rotating working platform when the two laser mutation signals are generated during each rotation, analyze and obtain the angular value of the angular hole at the current rotation circle, determine the angular value of the last rotation circle whose difference from the angular value of the previous circle is less than the preset threshold as the angular value of the angular hole, and rotate the center point of the angular hole of the casing to the XOZ plane according to the angular value of the angular hole; 2. The automatic laser alignment method for an aero-engine casing according to claim 1, characterized in that, Rotate the rotating working platform with the Z-axis of the alignment coordinate system as the central axis. During the rotation process, scan the reference circle of the casing with a laser rangefinder, and analyze and obtain the coordinate values of multiple scanning points on the reference circle of the casing in the alignment coordinate system according to the scanning results of the laser rangefinder; 3. The automatic laser alignment method for an aero-engine casing according to claim 1, characterized in that, The method for optimizing and fitting the center coordinates of the reference circle by using the least square method according to the X-axis coordinates and Y-axis coordinate values of multiple scanning points on the reference circle of the casing includes: Construct a fitting variance analysis function between the distance from the scanning point to the Z-axis and the fitting radius of the reference circle where E is the fitting variance between the distance from the scanning point to the Z-axis and the fitting radius of the reference circle, x i is the coordinate value of the i-th scanning point on the X-axis, y i is the coordinate value of the i-th scanning point on the Y-axis, n is the number of scanning points, A and B are coefficients, and C is a constant; Substitute the X-axis coordinate and Y-axis coordinate values of each scanning point into the fitting variance analysis function, and obtain the values of A, B, and C when the fitting variance is the smallest by least square fitting; According to the fitted A and B values, determine that the center coordinates of the reference circle in the XOY plane are 4. The automatic laser alignment method for an aeroengine casing according to claim 1, wherein According to the rotation angle of the rotary table when two laser mutation signals are generated in each rotation, use analysis to obtain the angular value θ of the angular hole in the current rotation j , where α j is the rotation angle value of the rotary work platform when the first laser mutation signal is generated in the j-th rotation, β j is the rotation angle value of the rotary work platform when the second laser mutation signal is generated in the j-th rotation, and m is the total number of rotations in the current rotation.

5. The automatic laser alignment method for an aero-engine casing according to claim 1, wherein, The preset threshold is 0.0001°; 6. An automatic laser alignment device for an aero-engine casing, which is used to implement the automatic laser alignment method for an aero-engine casing described in any one of claims 1-5, and is characterized in that, Including: A rotating working platform, the upper surface of the rotating working platform is a planar structure, the upper surface is used to place the aero-engine casing, and the rotation axis of the rotating working platform is perpendicular to the upper surface; A coordinate system construction module, which is used to establish an alignment coordinate system with the rotation center of the upper surface of the rotating working platform as the origin, two mutually perpendicular straight lines passing through the origin on the upper surface as the X-axis and the Y-axis respectively, and the straight line passing through the origin and perpendicular to the upper surface of the rotating working platform as the Z-axis; A data acquisition module, configured to obtain the coordinate values of multiple scanning points on the reference circle of the cylindrical thin-walled structure of the aero-engine casing placed on the rotating work platform with respect to the alignment coordinate system; A center coordinate analysis module, configured to optimize and fit the center coordinates of the reference circle by using the least squares method according to the X-axis coordinates and Y-axis coordinate values of multiple scanning points on the reference circle of the casing; A center alignment analysis module, configured to analyze and obtain the moving distance and direction of the casing according to the obtained center coordinates of the reference circle, so that the center of the reference circle of the casing coincides with the origin of the alignment coordinate system, and complete the center alignment of the casing; An angular hole alignment analysis module, configured to analyze and obtain the rotation angle of the casing after the center alignment is completed according to the angular value of the angular hole with respect to the X-axis, so as to rotate the center point of the angular hole of the casing to the XOZ plane.

7. The automatic laser alignment device for an aeroengine casing according to claim 6, characterized in that, In the center coordinate analysis module, the method for optimizing and fitting the center coordinates of the reference circle by using the least squares method includes: Construct a fitting variance analysis function between the distance from the scanning point to the Z-axis and the fitting radius of the reference circle where E is the fitting variance between the distance from the scanning point to the Z-axis and the fitting radius of the reference circle, and x i is the coordinate value of the i-th scanning point on the X-axis, and y i is the coordinate value of the i-th scanning point on the Y-axis, n is the number of scanning points, A and B are coefficients, and C is a constant; Substituting the X-axis coordinates and Y-axis coordinate values of each scanning point into the fitting variance analysis function, and obtaining the values of A, B, and C when the fitting variance is the smallest through least squares fitting; According to the fitted A and B values, determining that the center coordinates of the reference circle in the XOY plane are 8. The automatic laser alignment device for an aero-engine casing according to claim 6, characterized in that, In the angular hole alignment analysis module, the method for obtaining the angular value of the angular hole with respect to the X-axis includes: Emitting a laser beam along the X-axis towards the casing wall surface, adjusting the height of the laser beam to be flush with the angular hole on the casing, and arranging a laser receiver at a position directly opposite to the laser beam; the laser receiver and the laser beam light source are respectively located on both sides of the casing wall surface; Rotating the rotating work platform at least two circles, obtaining two laser mutation signals generated by the laser receiver when the angular hole of the casing passes through the laser beam during each rotation, and obtaining the rotation angle of the rotating workbench when the two laser mutation signals are generated; According to the rotation angle of the rotating workbench when two laser mutation signals are generated during each rotation, analyzing and obtaining the angular value of the angular hole at the current rotation circle, and determining the angular value of the last rotation circle whose difference from the angular value of the previous circle is less than a preset threshold as the angular value of the angular hole.

9. The automatic laser alignment device for an aero-engine casing according to claim 8, characterized in that, According to the rotation angle of the rotary table when two said laser mutation signals are generated in each rotation, use Analysis to obtain the angular value θ of the angular hole in the current rotation j , where α j is the rotation angle value of the rotary work platform when the first laser mutation signal is generated in the j-th rotation, β j is the rotation angle value of the rotary work platform when the second laser mutation signal is generated in the j-th rotation, and m is the total number of rotations in the current rotation.

10. The automatic laser alignment device for an aero-engine casing according to claim 6, characterized in that, It further includes an alignment platform, the bottom of the alignment platform is fixed, a zero-point positioning system is arranged on the alignment platform, the zero-point positioning system includes a plurality of lifting rods installed on the upper surface of the alignment platform, the rotating work platform is installed on the tops of the plurality of lifting rods, and the plurality of lifting rods are used to cooperate and adjust to make the upper surface of the rotating work platform in a horizontal state.

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