An Adaptive Axial Positioning Method for Solid Rocket Engine Non-Shaping Press-Fitting Tools

Abstract

This invention relates to the field of solid rocket motor manufacturing technology, specifically to an adaptive axial positioning method for a solid rocket motor end-effector press-fit tool. The method includes the following steps: a three-dimensional scan of the engine's outer surface is performed using a laser rangefinder rigidly connected to the robot's end effector, acquiring circumferential point cloud data of at least six radial cross-sections at equal intervals along the axial direction; elliptic equation fitting is performed on the point cloud data of each cross-section in the robot control module to solve for the coordinates of the centers of each ellipse; linear fitting is performed on all ellipse centers to obtain the unit vector of the engine's axial direction; the robot is adjusted to the press-fit height, and the angle of the press-fit tool is calculated using Newton's iteration method to align it with the unit vector, and the press-fit operation is performed along the vector direction without requiring any shaping. This invention, by positioning the engine along different axial directions, enables the robot to adaptively adjust the movement direction of the end-effector press-fit tool, avoiding quality defects caused by the press-fit direction not aligning with the engine's axial direction.

Description

Technical Field

[0001] This invention relates to the field of solid rocket motor manufacturing technology, specifically to an adaptive axial positioning method for solid rocket motor non-shaping press-fitting tools. Background Technology

[0002] Because solid rocket motor propellant propellant surfaces are often complex curved structures, shaping them using traditional cutting tools is difficult, leading to low shaping efficiency, reduced accuracy, and potential damage. Traditional shaping methods result in irreversible propellant surface defects and pose safety risks. Therefore, a no-shaping method can directly form complex propellant surfaces without complex shaping processes. However, the quality of the no-shaping process is affected by the quality of the axial positioning during tool press-fitting.

[0003] However, existing solutions for installing large engines primarily rely on manual hoisting, which commonly results in positioning errors and deviations between the non-aligning press-fit tool and the engine's axial direction. Furthermore, with only one vertical downward pressing degree of freedom, the non-aligning press-fit tool cannot adapt to the axial deviations of different engines, leading to axial misalignment and end-face tilting. Therefore, by extracting the axial parameters of the fixed engine, a robot can guide the press-fit tool to adapt to the axial direction of different engines, thereby accurately positioning the pressing direction. This method can effectively improve the accuracy of the non-aligning process and product quality. Summary of the Invention

[0004] The purpose of this invention is to provide an adaptive axial positioning method for a solid rocket motor press-fit tool without shaping. This method can extract the fixed axial parameters of the engine to make the press-fit tool adapt to the axial direction of different engines, thereby accurately positioning the press-fit direction.

[0005] The technical solution adopted by this invention to achieve the above objectives is: an adaptive axial positioning method for a solid rocket motor non-shaping press-fitting tool, comprising the following steps:

[0006] 1) Physical data acquisition: The outer surface of the engine is scanned in three dimensions by a laser rangefinder rigidly connected to the end of the robot, and circumferential point cloud data of at least 6 radial sections are acquired at equal intervals along the axial direction;

[0007] 2) Geometric parameter calculation: In the robot control module, ellipse equation fitting is performed on the point cloud of each section to solve for the coordinates of the center of each ellipse;

[0008] 3) Spatial axis generation: The least squares method is used to linearly fit the centers of all ellipses to obtain the unit vector of the engine axis;

[0009] 4) Axial pressing execution: The robot is adjusted to the pressing height, and the pressing tool angle is calculated by Newton's iteration method to make it coincide with the unit vector, and the pressing operation without shaping is performed along the vector direction.

[0010] In step 1), the laser rangefinder is rigidly connected through the robot end flange. During scanning, the robot end effector moves along the engine axis at a preset speed and rotates around the tool coordinate system Z-axis for scanning.

[0011] Step 1) specifically includes:

[0012] 1-1) Establish the coordinate system of the measuring tool, which refers to the coordinate system where the robot is equipped with the laser rangefinder sensor. The coordinate data of the radial section sampling point are measured by the laser rangefinder sensor.

[0013] 1-2) Let the measuring section be γ j The cross-sectional height is Z1, and the sampling point is P. ij The coordinates of the sampling point are (X ij ,Y ij Each radial section requires at least 6 sampling points; after each radial section sampling is completed, the linear motion module of the laser rangefinder sensor is adjusted to move a fixed distance h along the Z-axis to proceed to the next radial section γ. j+1 Sampling continues until j = m and Z = Z. m That is, all sampling is completed;

[0014] 1-3) Define the sampling points of each cross section as a column vector for fitting the cross section equation.

[0015] In steps 1-2), the fixed distance h is:

[0016]

[0017] Among them, Z m Z1 is the upper limit of the height of the sampling radial section, and m is the number of sampling radial sections.

[0018] Step 2) includes the following steps:

[0019] 2-1) Perform noise filtering on the point cloud data; and define the coordinates of the ellipse center as O. j The specific parameters are (X) 0j ,Y 0j Z j By fitting the ellipse equations of each cross section, the coordinates of the centers of m ellipses are obtained.

[0020] 2-2) For an ellipse with a radial cross-section, the equation satisfies, namely:

[0021] Ax 2+Bxy+Cy 2 +Dx+Ey+F=0

[0022] Where A, B, C, D, E, and F are all constants;

[0023] 2-3) Substituting the coordinates of the radial section sampling points, the coordinates of the ellipse's center can be calculated as follows:

[0024] Step 3) includes the following steps:

[0025] 3-1) For a straight line in space, the following conditions must be met:

[0026]

[0027] Where k1, k2, b1, and b2 are parameters of the equation of a straight line in space, and satisfy the following:

[0028] 3-2) By calculating and minimizing the sum of squares of the residuals, the equation parameters k1, k2, b1, and b2 can be solved, i.e.:

[0029]

[0030] 3-3) The normal vector of the fitted line is the normal vector of the actual engine (6) axis; and the vector is normalized to:

[0031] Step 4) includes the following steps:

[0032] The angle of the robot's end effector pressing tool in the robot coordinate system is calculated based on the target vector.

[0033] 4-1) Use the preset initial guess value, tolerance error, maximum number of iterations, and the normal vector of the axis direction as the initial input; extract the direction vector and decompose it into three components;

[0034] 4-2) Enter the Newton iteration loop, calculate the current error, determine convergence, calculate the Jacobian matrix, and finally update the angle estimate;

[0035] 4-3) Convert the radian result into an angle, and feed the output angle back to the robot so that it can control the pressing tool to perform a non-shaping pressing operation along the engine axial direction.

[0036] In step 4-1), the initial guessed radians are set as follows: ABC0 = [0.05, 0.05, 0.05]. T Define the convergence threshold: e = 10 -8 Define the maximum number of iterations: N max =100.

[0037] Step 4-2) specifically involves:

[0038] a. Extract the current radian estimate:

[0039] A=ABC0[1], B=ABC0[2], C=ABC0[3]

[0040] b. Calculate the rotation matrix error function:

[0041]

[0042] c. If the error norm satisfies: Then it converges and exits, stopping the iteration loop;

[0043] d. Calculate the Jacobian matrix:

[0044]

[0045] Update angle estimation:

[0046] ABC = ABC0 - J * f

[0047] Among them, J * Indicates the pseudo-inverse of a matrix;

[0048] f. Update the iteration variable: ABC0 = ABC.

[0049] An axial positioning system for an adaptive axial positioning method of a solid rocket motor non-shaping press-fitting tool includes:

[0050] The measurement component is a laser rangefinder mounted on the robot. The laser rangefinder is located on the linear motion module and is used to establish a coordinate system for the measurement tool and to perform equidistant sampling of multiple radial sections of the engine to obtain the coordinate vector of the sampling points.

[0051] An ellipse fitting module, connected to the measurement component, is used to fit the ellipse equation to the sampling points of each radial section and calculate the coordinates of the ellipse center of each section.

[0052] The linear fitting module, connected to the ellipse fitting module, uses the least squares method to perform linear fitting on the coordinates of all ellipse center points, generates engine axis parameters, and calculates the corresponding unit vectors.

[0053] The drive control module includes a linear motion module, a pressing tool, and a robot. It is used to drive the laser rangefinder to perform a three-dimensional scan of the engine's outer surface through the linear motion module. At the same time, it calculates the robot's end-effector posture based on Newton's iteration method, so that the pressing tool's axis coincides with the unit vector, and controls the pressing tool to perform a downward pressing motion along the engine's axis.

[0054] The present invention has the following beneficial effects and advantages:

[0055] 1. This invention automatically extracts the actual axial parameters of the fixed engine through multi-section ellipse fitting and linear regression, overcoming the problem of press-fit direction deviation caused by large aspect ratio and positional deviation in traditional methods. Compared with manual calibration or passive adjustment of fixed position, this method can dynamically correct axial deviation, significantly improving the accuracy of the press-fit tool direction coinciding with the engine axis, and improving the forming quality of the non-shaping process.

[0056] 2. This invention calculates the Euler angles of the robot's end effector in real time using Newton's iteration method, ensuring rapid convergence and alignment of the tool's posture with the engine axis unit vector. Compared to traditional trial-and-error methods or fixed path planning, this method significantly reduces adjustment time and avoids the risk of damage to the propellant surface caused by repeated adjustments.

[0057] 3. This invention combines non-shaping pressing with robot active axial positioning to directly form complex drug shapes without the need for traditional tool shaping, thus eliminating irreversible damage and safety risks to the processed drug shapes caused by the shaping process. Attached Figure Description

[0058] Figure 1 This is a flowchart illustrating the present invention;

[0059] Figure 2 This is a schematic diagram illustrating the axial positioning error of the non-forming press-fitting method of the present invention;

[0060] Figure 3 This is a flowchart illustrating the implementation method of the present invention;

[0061] Figure 4 This is a structural diagram of the apparatus for implementing the method of the present invention;

[0062] Figure 5 This is a diagram showing the effect of adaptive axial positioning of the non-shaping press-fitting tool of the present invention;

[0063] Among them: 1 is the robot, 2 is the pressing tool, 3 is the linear motion module, 4 is the laser rangefinder, 5 is the non-shaping tooling, 6 is the engine, 7 is the engine mounting base, and 8 is the workshop floor. Detailed Implementation

[0064] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0065] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in detail below with reference to the accompanying drawings and specific implementation methods.

[0066] like Figure 1The diagram shown is a flowchart of the present invention. The present invention provides an adaptive axial positioning method for a solid rocket motor non-shaping press-fitting tool, comprising the following steps:

[0067] Step 1. Establish the coordinate system of the measuring tool and obtain the coordinate vector of the sampling points of the engine longitudinal section;

[0068] Step 2. Fit the longitudinal cross-section ellipse equation of the sampling points to obtain the coordinates of the ellipse center;

[0069] Step 3. Perform linear fitting on the centers of the ellipses of each radial section to obtain the unit vector of the fitted line;

[0070] Step 4. The robot is adjusted to the height position and performs a non-shaping pressing operation along the adaptive vector direction.

[0071] Example 1:

[0072] Specifically, this invention focuses on solid rocket motors:

[0073] like Figure 4 The diagram shown is a structural diagram of the apparatus for implementing the method of the present invention. This embodiment describes an axial positioning system for an adaptive axial positioning method of a solid rocket motor non-shaping press-fitting tool, comprising:

[0074] The measurement component is: a laser rangefinder 4 mounted on robot 1. The laser rangefinder 4 is located on linear motion module 3 and is used to establish a coordinate system for the measuring tool and to perform equidistant sampling of multiple radial sections of the engine to obtain the coordinate vector of the sampling points.

[0075] An ellipse fitting module, connected to the measurement component, is used to fit the ellipse equation to the sampling points of each radial section and calculate the coordinates of the ellipse center of each section.

[0076] The linear fitting module, connected to the ellipse fitting module, uses the least squares method to perform linear fitting on the coordinates of all ellipse center points, generates engine axis parameters, and calculates the corresponding unit vectors.

[0077] The drive control module includes a linear motion module 3, a pressing tool 2, and a robot 1. It is used to drive the laser rangefinder 4 to perform a three-dimensional scan of the outer surface of the engine through the linear motion module 3. At the same time, it calculates the end posture of the robot 1 based on the Newton iteration method, so that the axis of the pressing tool 2 coincides with the unit vector, and controls the pressing tool 2 to perform a pressing motion along the axis of the engine 1.

[0078] The object being tested is a solid rocket engine. The engine 6 is fixed on the engine mounting base 7, which is installed on the horizontal workshop floor 8. The non-shaping fixture 5 is placed on the engine 6 to cooperate with the pressing tool 2 and achieve flatness during the pressing process of the robot 1.

[0079] The specific method of this embodiment is as follows:

[0080] Step 1: Establish the coordinate system of the measuring tool and obtain the coordinate vector of the sampling points of the longitudinal section of the engine;

[0081] like Figure 2 As shown, there is a deviation between the ideal pose and the actual pose of engine 6, resulting in a certain angle between the axis of engine 6 and the ideal axis. To adapt to the actual pose of each engine 6, it is necessary to measure its corresponding axis parameters. First, a coordinate system for the measurement tool is established, referring to the coordinate system where the laser rangefinder sensor 4 is mounted on robot 1. The coordinate data of the radial cross-section sampling points are measured using the laser rangefinder sensor. The measurement cross-section is γ. j The cross-sectional height is Z1, and the sampling point is P. ij The coordinates of the sampling point are (X ij ,Y ij Each radial section requires at least 6 sampling points. After each radial section sampling is completed, the linear motion module 3 of the laser rangefinder sensor needs to be moved a fixed distance h along the Z-axis to proceed to the next radial section γ. j+1 Sampling continues until j = m and Z = Z. m This completes all sampling. The sampling points for each cross-section are defined as a column vector; these sampling point parameters will be used to fit the cross-sectional equations. The process is as follows: Figure 3 As shown in Step 1.

[0082]

[0083] Among them, Z m Z1 is the upper limit of the height of the sampling radial section, and m is the number of sampling radial sections.

[0084] Step 2: Fit the ellipse equation of the longitudinal section of the engine to the sampling points and obtain the coordinates of the ellipse center;

[0085] like Figure 2 As shown, due to axial deviation, the radial cross-section of a real solid rocket motor is an ellipse. The ellipse equation is fitted by sampling points of each radial cross-section. The coordinates of the ellipse center are defined as O. j The specific parameters are (X) 0j ,Y 0j Z j By fitting the ellipse equations of each cross-section, the coordinates of the centers of m ellipses are obtained. The process is as follows: Figure 3 As shown in Step 2.

[0086] For an ellipse with a radial cross-section, the following conditions must be met:

[0087] Ax 2 +Bxy+Cy 2 +Dx+Ey+F=0

[0088] Where A, B, C, D, E, and F are all constants.

[0089] The coordinates of the ellipse's center can be calculated by substituting the coordinates of the radial section sampling points.

[0090]

[0091] Step 3: Perform linear fitting on the center of the ellipse of each radial section to obtain the unit vector of the fitted line;

[0092] like Figure 2 As shown, due to the large number of sampling sections, linear fitting is performed on the center coordinates of each section to more accurately reflect the axial parameters of engine 6. Then, the unit vector of the corresponding engine 6 axis is calculated based on the fitted linear equation.

[0093] The unit vectors along the six axes of the engine are obtained by linearly fitting all the elliptical centers using the least squares method. The process is as follows: Figure 3 As shown in Step 3.

[0094] For a straight line in space, the following conditions are satisfied:

[0095]

[0096] The formula can be converted into the following form:

[0097]

[0098] in

[0099] By calculating the sum of squares of the residuals and minimizing it.

[0100]

[0101] The equation parameters k1, k2, b1, and b2 can be solved using the method described above.

[0102]

[0103] At this point, the normal vector of the fitted line can be represented, which is the normal vector of the actual engine's 6-axis direction.

[0104] And then the vectors are normalized.

[0105]

[0106] Step 4: The robot is adjusted to the height position and performs a non-shaping pressing operation along the adaptive vector direction.

[0107] Through the calculations in the aforementioned steps, the axial direction vector of the actual engine 6 is obtained, providing direction for robot 1 to control the pressing tool 2 to press down the non-shaping fixture 5. Before this, the pressing tool 2 needs to be adjusted to the standby position on top of the engine 6. After robot 1 is adjusted to the pressing height, the angle of the pressing tool is calculated using Newton's iteration method to ensure it coincides with the unit vector, thus ensuring that the pressing direction coincides with the axial direction of the actual engine 6. The process is as follows: Figure 3 As shown in Step 4. The effect after axial positioning is as follows. Figure 5 As shown.

[0108] The Newton-Raphson iteration method aims to determine the angle of the end effector tool 2 of robot 1 in the robot coordinate system based on the target vector. Initial inputs are set with a preset initial guess value, tolerance error, maximum number of iterations, and the normal vector of the axis direction. The direction vector is extracted and decomposed into three components. The Newton-Raphson iteration loop is then entered, sequentially calculating the current error, determining convergence, calculating the Jacobian matrix, and finally updating the angle estimate. Once the error is less than the tolerance error, the radian result is output. Finally, the radian result is converted into an angle. The output angle is fed back to robot 1, enabling it to control the pressing tool to perform a non-shaping pressing operation along the engine axis. The specific algorithm steps are as follows:

[0109] Input: Target direction vector v = [m, n, k] T , where m 2 +n 2 +k 2 =1;

[0110] Output: Euler angles A, B, C (unit: °);

[0111] 1: Initialization parameters:

[0112] Set the initial guess in radians: ABC0 = [0.05, 0.05, 0.05] T (rad);

[0113] Define the convergence threshold: e = 10 -8 ;

[0114] Define the maximum number of iterations: N max =100;

[0115] 2: Newton's iterative process:

[0116] a. Extract the current angle estimate:

[0117] A=ABC0[1], B=ABC0[2], C=ABC0[3]

[0118] b. Calculate the rotation matrix error function:

[0119]

[0120] c. If the error norm satisfies Then it converges and exits;

[0121] d. Calculate the Jacobian matrix:

[0122]

[0123] e. Update radian estimate (pseudo-inverse method):

[0124] ABC = ABC0 - J * f(where J) * (representing the pseudo-inverse of a matrix)

[0125] f. Update the iteration variable:

[0126] ABC0 = ABC

[0127] 3: Output Results:

[0128] If the number of iterations t = N max The system displays a warning: "Maximum number of iterations reached."

[0129] Converting radians to angles, i.e.:

[0130]

[0131] Finally, the output angle is fed back to the robot, enabling it to control the pressing tool to perform a non-shaping pressing operation along the engine axial direction.

[0132] The apparatus involved in the implementation method is mainly aimed at the non-shaping press-fitting process of solid rocket motor robots. The kinematics of the robot has been introduced in detail. Therefore, this description only introduces the adaptive axial positioning method of the non-shaping tool.

[0133] Those skilled in the art will understand that the above description is merely a preferred embodiment of the present invention, and the features described in the various embodiments and / or claims of this disclosure can be combined or combined in various ways, even if such combinations or combinations are not explicitly described in this disclosure. This is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

[0134] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention. Clearly, those skilled in the art can make various alterations and modifications to the invention without departing from its spirit and scope. Thus, if these modifications and modifications of the invention fall within the scope of the claims and their equivalents, the invention is also intended to include these modifications and modifications.

Claims

1. An adaptive axial positioning method for a solid rocket motor non-shaping press-fitting tool, characterized in that, Includes the following steps: 1) Physical data acquisition: The outer surface of the engine is scanned in three dimensions by a laser rangefinder rigidly connected to the end of the robot, and circumferential point cloud data of at least 6 radial sections are acquired at equal intervals along the axial direction; 2) Geometric parameter calculation: In the robot control module, ellipse equation fitting is performed on the point cloud of each section to solve for the coordinates of the center of each ellipse; 3) Spatial axis generation: The least squares method is used to linearly fit the centers of all ellipses to obtain the unit vector of the engine axis; 4) Axial pressing execution: The robot is adjusted to the pressing height, and the pressing tool angle is calculated using Newton's iteration method to make it coincide with the unit vector, and a non-shaping pressing operation is performed along the vector direction; Step 4) includes the following steps: The angle of the robot's end effector pressing tool in the robot coordinate system is calculated based on the target vector. 4-1) Use the preset initial guess value, tolerance error, maximum number of iterations, and the normal vector of the axis direction as the initial input; extract the direction vector and decompose it into three components; 4-2) Enter the Newton iteration loop, calculate the current error, determine convergence, calculate the Jacobian matrix, and finally update the angle estimate; 4-3) Convert the radian result into an angle, and feed the output angle back to the robot so that it can control the pressing tool to perform a non-shaping pressing operation along the engine axial direction.

2. The adaptive axial positioning method for a solid rocket motor non-shaping press-fitting tool according to claim 1, characterized in that, In step 1), the laser rangefinder is rigidly connected through the robot end flange. During scanning, the robot end effector moves along the engine axis at a preset speed and rotates around the tool coordinate system Z-axis for scanning.

3. The adaptive axial positioning method for a solid rocket motor non-shaping press-fitting tool according to claim 1, characterized in that, Step 1) specifically refers to: 1-1) Establish the coordinate system of the measuring tool, which refers to the coordinate system where the robot is equipped with the laser rangefinder sensor. The coordinate data of the radial section sampling point are measured by the laser rangefinder sensor. 1-2) Let the measuring section be... The cross-sectional height is Sampling points are The coordinates of the sampling point are Each radial section requires at least 6 sampling points; after each radial section sampling is completed, the linear motion module of the laser rangefinder sensor is adjusted to move a fixed distance h along the Z-axis to proceed to the next radial section. Sampling until j=m, That is, all sampling is completed; 1-3) Define the sampling points of each cross section as a column vector for fitting the cross section equation.

4. The adaptive axial positioning method for a solid rocket motor non-shaping press-fitting tool according to claim 3, characterized in that, In steps 1-2), the fixed distance h is: ； in, This represents the upper limit of the sampling radial section height. is the upper limit of the sampling radial section height, and m is the number of sampling radial sections.

5. The adaptive axial positioning method for a solid rocket motor non-shaping press-fitting tool according to claim 1, characterized in that, Step 2) includes the following steps: 2-1) Noise filtering processing is performed on the point cloud data; and the elliptical center coordinates are defined as O j , and the specific parameters are (X 0j , Y 0j , Z j ); by fitting the elliptical equation of each section, m elliptical center coordinates are obtained; 2-2) For an ellipse with a radial cross-section, the equation satisfies, namely: ； Where A, B, C, D, E, and F are all constants; 2-3) Substituting the coordinates of the radial section sampling points, the coordinates of the ellipse's center can be calculated as follows: .

6. The adaptive axial positioning method for a solid rocket motor non-shaping press-fitting tool according to claim 1, characterized in that, Step 3) includes the following steps: 3-1) For a straight line in space, the following conditions must be met: ； Where k1, k2, b1, and b2 are parameters of the equation of a straight line in space, and satisfy the following: ; 3-2) By calculating and minimizing the sum of squares of the residuals, the equation parameters k1, k2, b1, and b2 can be solved, i.e.: ； 3-3) The normal vector of the fitted line, i.e. the normal vector of the actual engine (6) axis; and the vector is normalized to: .

7. The adaptive axial positioning method for a solid rocket motor non-shaping press-fitting tool according to claim 1, characterized in that, In Step 4-1), set the initial guess for the radian: ABC0 = [0.05, 0.05, 0.05] T ; define the convergence threshold: e = 10 -8 ; define the maximum number of iterations: N max = 100.

8. The adaptive axial positioning method for a solid rocket motor non-shaping press-fitting tool according to claim 1, characterized in that, Step 4-2) specifically involves: a. Extract the current angle estimate: A=ABC0[1], B=ABC0[2], C=ABC0[3] b. Calculate the rotation matrix error function: ； c. If the error norm satisfies: Then it converges and exits; d. Calculate the Jacobian matrix: ； e. Update radian estimation: ABC=ABC0- J * f； in, J * Indicates the pseudo-inverse of a matrix; f. Update the iteration variable: ABC0 = ABC.

9. The axial positioning system of the adaptive axial positioning method for a solid rocket motor non-shaping press-fitting tool according to any one of claims 1 to 8, characterized in that, include: The measurement component is a laser rangefinder mounted on the robot. The laser rangefinder is located on the linear motion module and is used to establish a coordinate system for the measurement tool and to perform equidistant sampling of multiple radial sections of the engine to obtain the coordinate vector of the sampling points. An ellipse fitting module, connected to the measurement component, is used to fit the ellipse equation to the sampling points of each radial section and calculate the coordinates of the ellipse center of each section. The linear fitting module, connected to the ellipse fitting module, uses the least squares method to perform linear fitting on the coordinates of all ellipse center points, generates engine axis parameters, and calculates the corresponding unit vectors. The drive control module includes a linear motion module, a pressing tool, and a robot. It is used to drive the laser rangefinder to perform a three-dimensional scan of the engine's outer surface through the linear motion module. At the same time, it calculates the robot's end-effector posture based on Newton's iteration method, so that the pressing tool's axis coincides with the unit vector, and controls the pressing tool to perform a downward pressing motion along the engine's axis.

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