An adaptive measurement and grinding system and method for the tip welding and extension area of an aero-engine blade

Abstract

The present invention belongs to, but is not limited to, the field of aviation technology, and particularly relates to an adaptive measurement and grinding system and method for the welding extension area of aero-engine blade tips. The robot body is mainly responsible for the measurement and grinding trajectory, the rigid-flexible coupling compliant actuator is responsible for controlling the grinding contact force, the line laser measurement system is used for the measurement of the welding extension area and the analysis of the remaining amount in the extension area, the robot quick-change device is used for the quick replacement of the line laser and the rigid-flexible coupling compliant actuator, the belt grinder is responsible for the grinding of the extension area, and the positioning fixture is responsible for the clamping and positioning of the blade; the grinding process planning system plans the contact force of the grinding process through the welding allowance and generates the grinding trajectory according to the line laser measurement point cloud; the end of the rigid-flexible coupling compliant actuator is connected to the belt grinder, and its top is connected to the tool side of the robot quick-change device; the robot quick-change device uses gas to lock the main side and the tool side, providing great flexibility for the automatic replacement of tools.

Description

Technical Field

[0001] The present invention belongs to, but is not limited to, the field of aviation technology, and particularly relates to an adaptive measurement and grinding system and method for the welding and lengthening area of the tip of an aero-engine blade. Background Art

[0002] Aero-engine blades work in high-temperature, high-pressure, cooling thermal fatigue, and complex stress environments for a long time, which easily leads to wear and corrosion damage at the tip of the blade, resulting in loss of tip material, thinning of the thickness, or cracks. The damaged blade will seriously affect the flight safety of the aircraft. Aero-engine blades are usually made of high-performance alloy materials through complex processes and are very expensive. Therefore, timely repair of damaged blades can not only eliminate potential safety hazards but also have important economic value. Currently, the common method for repairing the tip of a blade is to first repair the damaged area at the tip through laser cladding and manual welding, and then manually measure and grind the welded and lengthened area to make it smoothly transition to the non-damaged area, and the overall repaired surface meets the tolerance requirements of the repaired blade. Although manual measurement and grinding of the welded and lengthened area of the blade can be achieved, the grinding technology requires a high level of proficiency from workers, it is difficult to ensure processing consistency and stability, and the efficiency of manual measurement and grinding is low.

[0003] In view of the above analysis, the technical problems that urgently need to be solved in the existing technology are: the grinding technology requires a high level of proficiency from workers, it is difficult to ensure processing consistency and stability, and the efficiency of manual measurement and grinding is low. Summary of the Invention

[0004] Aiming at the problems existing in the existing technology, the present invention provides an adaptive measurement and grinding system and method for the welding and lengthening area of the tip of an aero-engine blade, aiming to improve the measurement and grinding efficiency of the welding and lengthening area of the tip of an aero-engine blade, realize a smooth transition between the welded and lengthened area and the non-lengthened area after grinding, and ensure processing consistency and stability.

[0005] The present invention is implemented as follows. An adaptive measurement and grinding system for the welding and lengthening area of the tip of an aero-engine blade includes:

[0006] A robot body, a rigid-flexible coupling compliant actuator, a line laser measurement system, a robot quick-change device, a belt grinder, a positioning fixture, and a grinding process planning system.

[0007] The robot body is mainly responsible for the measurement and grinding trajectory, the rigid-flexible coupling compliant actuator is responsible for controlling the grinding and polishing contact force, the line laser measurement system is used for measuring the welding and lengthening area and analyzing the allowance in the lengthening area, the robot quick-change device is used for quickly replacing the line laser and the rigid-flexible coupling compliant actuator, the belt grinder is responsible for grinding the lengthening area, and the positioning fixture is responsible for clamping and positioning the blade.

[0008] The grinding process planning system plans the contact force during the grinding process through the welding allowance and generates the grinding trajectory based on the line laser measurement point cloud.

[0009] The end of the rigid-flexible coupling compliant actuator is connected to the belt grinder, and its top is connected to the tool side of the robot quick-change device.

[0010] The main side of the robot quick-change device is installed at the end of the robot body. Different tool sides are respectively connected to the rigid-flexible coupling compliant actuator and the line laser measuring instrument. The robot quick-change device uses gas to lock the main side and the tool side, providing great flexibility for automatic tool change.

[0011] The rigid-flexible coupling compliant actuator can ensure the compliance of the grinding process and the stability of the contact force, thus ensuring the smooth transition between the welded extension area and the non-welded area.

[0012] Before the first use of the line laser measurement system, hand-eye calibration is required to obtain the hand-eye transformation matrix between the line laser coordinate system and the robot end coordinate system.

[0013] Another object of the present invention is to provide an adaptive measurement and grinding method for the welded extension area of the aero-engine blade tip, which uses the above-mentioned aero-engine blade tip welded extension area adaptive measurement and grinding system, including:

[0014] S1. The robot end uses the quick-change device to connect the line laser measuring instrument, and scans the fixed standard ball at different postures for hand-eye calibration, which is only required for the first use.

[0015] S2. Manually install the blade to be ground on the positioning fixture.

[0016] S3. The robot connects the line laser measuring instrument through the quick-change device, and scans and measures the blade according to the planned path to obtain the welding allowance in the welded extension area and the position of the welded extension in the robot base coordinate system.

[0017] S4. Generate the grinding trajectory for rough grinding of the robot for the welded extension of the blade tip according to the measurement point cloud.

[0018] S5. Plan the contact force and the robot feed speed during the rough grinding process according to the material removal model of the low-grit number (80#) abrasive belt.

[0019] S6. The robot connects the rigid-flexible coupling compliant actuator through the quick-change device for rough grinding to quantitatively remove most of the welding materials.

[0020] S7. The robot connects the line laser measuring instrument through the quick-change device and measures the welding allowance in the welded extension area and the position of the welded extension in the robot coordinate system again.

[0021] S8. Generate the grinding trajectory for fine grinding of the robot for the welded extension of the blade tip according to the measurement point cloud.

[0022] S9. Plan the contact force and the robot feed speed of the fine grinding process according to the material removal model of the high-mesh (800#) abrasive belt.

[0023] S10. The robot is connected to the rigid-flexible coupling compliant actuator through a quick-change device for fine grinding to ensure a smooth transition between the extended region and the non-extended region.

[0024] S11. The robot is connected to the line laser measuring instrument through a quick-change device and finally measured to ensure that the quality of the ground blade is qualified.

[0025] Furthermore, the specific principle of S1 is as follows:

[0026] The line laser scans a standard sphere at an unknown cross-section to obtain an arc in the line laser measurement coordinate system, and the center coordinates of the circle are determined by arc fitting. Combining the radius R of the standard sphere and the radius r of the fitted circle, the center coordinates of the sphere in the line laser measurement coordinate system are established. s P = s x s y s z] T , and the point P is in the robot base coordinate system b P, the robot end coordinate system e P, and the line laser measurement coordinate system s P has the following relationship:

[0027]

[0028]

[0029] Where and are the homogeneous transformation matrices from the robot base coordinate system to the end coordinate system and from the robot end coordinate system to the line laser measurement coordinate system respectively. By decomposing the homogeneous transformation matrix into a rotation matrix and a translation matrix, we have:

[0030]

[0031] Where and are respectively the rotation component and translation component, and are respectively the rotation component and translation component.

[0032] Simplifying formula (3) gives:

[0033] At this time, measuring the center of the sphere P with n different poses can obtain the following formula:

[0034]

[0035] wherein 1 ≤ i ≤ n, i is the measurement serial number, and n is the number of measurement groups.

[0036] Taking the difference between any two different equalities of Equation (5) gives equations, which can be obtained after simplification as follows:[[]]

[0037]

[0038] Equation (6) is in the form of a general linear equation system AX = b, where A is a matrix, wherein

[0039]

[0040] Generally Therefore, the least squares method can be used to solve the hand-eye calibration matrix. Then:[[]]

[0041]

[0042] Furthermore, in step S3, the voxel grid downsampling is first used to reduce the point cloud density and obtain a uniform point cloud distribution, and Gaussian filtering is used for preprocessing the point cloud data; then the welding extension area is identified through curvature mutation detection and the remaining non-extension areas are segmented, the non-extension areas are fitted and extended to the extension area as the theoretical surface, and then the point cloud data of the welding extension area is subtracted from the theoretical surface height to obtain the margin of the welding extension.

[0043] Furthermore, in step S4, the robot grinding trajectory converts the point cloud of the welding area identified in step S3 into the data in the robot base coordinate system through the hand-eye calibration matrix in S1, and then generates the motion trajectory in the base coordinate system from the center line of the welding extension area.

[0044] Furthermore, the material removal model in steps S5 and S9 adopts the following form:[[]]

[0045]

[0046] where h is the removal depth, k h The material removal coefficient can be calibrated through experiments, V r is the rotational speed of the belt grinder, V t is the tangential feed speed of the robot, F is the grinding contact force, R1 is the radius of the contact wheel of the belt grinder, and R2 is the radius of curvature of the workpiece contact point.

[0047] Furthermore, with a constant robot feed speed, the required contact force is planned according to the welding extension margin h j and the radius of curvature R 2j at different positions in the welding extension area to achieve quantitative and uniform removal. Wherein:[[]]

[0048]

[0049] Another object of the present invention is to provide a computer device, which includes a memory and a processor. The memory stores a computer program. When the computer program is executed by the processor, the processor executes the steps of the adaptive measurement and grinding method for the welded extension area of the aero-engine blade tip.

[0050] Another object of the present invention is to provide a computer-readable storage medium storing a computer program. When the computer program is executed by the processor, the processor executes the steps of the adaptive measurement and grinding method for the welded extension area of the aero-engine blade tip.

[0051] Another object of the present invention is to provide an information data processing terminal, which includes the adaptive measurement and grinding system for the welded extension area of the aero-engine blade tip.

[0052] Combined with the above technical solutions and the solved technical problems, the advantages and positive effects of the technical solution to be protected by the present invention are as follows:

[0053] First, the beneficial effects of the present invention:

[0054] (1) The present invention designs an efficient processing method of "robot + line laser measuring instrument + rigid-flexible coupling compliant actuator" applicable to the measurement and grinding of the welded extension of the blade tip. Through this innovative method, an automated, high-precision and consistent process of grinding the welded extension of the blade tip is realized, greatly improving the efficiency and quality of blade repair.

[0055] (2) The measurement and grinding are realized by replacing tools through the robot quick-change device. This design enables the blade to be clamped only once, avoiding the errors and time waste caused by multiple clamping, and greatly improving the repair efficiency.

[0056] (3) The grinding contact force and the robot grinding trajectory are adaptively generated according to the measurement results of the remaining amount in the welded extension area of the blade tip, so that the control of the grinding removal amount is more accurate, avoiding over-grinding or under-grinding, and better ensuring the smooth transition between the welded extension area and the non-extended area after grinding. The grinding trajectory generated by precise measurement and the contact force planned according to the material removal model ensure the surface quality and dimensional accuracy of the repaired blade.

[0057] Second, the expected benefits and commercial value after the transformation of the technical solution of the present invention: The present invention is conducive to reducing the maintenance cost of aero-engines. Since the processing technology of aero-engine blades is complex and expensive, for example, the price of a new fan blade of a CF556-5B engine is about 270,000 yuan, while the maintenance cost is only about 10,000 yuan. By introducing a robot measurement and grinding system, the present invention can not only effectively improve the quality and efficiency of the repair of blade tip welding and elongation, but also reduce the replacement cost caused by blade damage, with significant economic benefits. At the same time, this method can be extended and applied to other fields of welding seam measurement and grinding, with a broad market prospect.

[0058] The technical solution of the present invention overcomes the technical prejudice: Traditional blade grinding technology mainly relies on manual operation, which has great uncertainty and errors, and it is difficult to ensure grinding accuracy and consistency. While advanced foreign grinding methods mostly use special equipment for grinding. Although these equipment can provide higher grinding accuracy and efficiency, their cost is expensive and their applicability is low, making it difficult to meet the grinding requirements of different blades. By introducing a robot, a line laser measuring instrument and a rigid-flexible coupling actuator, the present invention provides a more economical, efficient and widely applicable solution. During the grinding process, the line laser measuring instrument is used for high-precision measurement and positioning, ensuring the accurate identification and measurement of the welding and elongation area. At the same time, the rigid-flexible coupling actuator can flexibly adjust the contact force and path of grinding, ensuring the stability and consistency of the grinding process. This combination not only significantly improves the accuracy and consistency of grinding, reduces the errors and uncertainties brought by manual operation, but also can meet the repair requirements of different types of blade tip welding and elongation, overcoming the limitations of traditional methods and special equipment in terms of applicability.

[0059] Third, by introducing advanced parameters, algorithms and mathematical models, the technical solution of the present invention solves multiple technical problems in the prior art and has made remarkable technical progress. The following is a detailed analysis of these technical problems and technical progress:

[0060] Technical problems:

[0061] 1) Hand-eye calibration accuracy problem: In the traditional robot measurement and grinding system, the accuracy of hand-eye calibration directly affects the accuracy of measurement and grinding. The present invention improves the calibration accuracy by using the method of line laser scanning a standard ball for hand-eye calibration.

[0062] 2) Welding and elongation area identification and allowance measurement problem: Accurately identifying the welding and elongation area and measuring its allowance are the prerequisites for precise grinding. The present invention effectively identifies and measures the allowance of the welding and elongation area through point cloud processing technologies such as curvature mutation detection and Gaussian filtering.

[0063] 3) Grinding trajectory planning problem: Traditional grinding methods cannot accurately plan the trajectory according to the shape and allowance of the welded extension area. The present invention realizes more accurate grinding by generating a grinding trajectory based on point cloud.

[0064] 4) Accuracy problem of material removal model: The accuracy of the material removal model is crucial for realizing quantitative removal and ensuring grinding quality. The present invention adopts a material removal model considering multiple influencing factors, improving the accuracy and efficiency of grinding.

[0065] Technological progress:

[0066] 1) Improve the accuracy of hand-eye calibration: By the method of line laser scanning a standard ball, combining homogeneous transformation matrix and least squares method to solve the hand-eye calibration matrix, the accuracy and stability of hand-eye calibration are significantly improved.

[0067] 2) Accurately identify and measure the welded extension area: Using technologies such as voxel grid downsampling, Gaussian filtering and curvature mutation detection, the welded extension area is accurately identified and its allowance is accurately measured, providing a basis for subsequent accurate grinding.

[0068] 3) Optimize the grinding trajectory planning: By converting the point cloud of the identified welding area into data in the robot base coordinate system and generating a motion trajectory based on the center line, a more accurate and efficient grinding trajectory planning is realized.

[0069] 4) Improve the material removal model: Adopt a material removal model considering multiple factors such as the rotational speed of the belt grinder, the feeding speed of the robot, and the grinding contact force, improving the quantitative removal accuracy and surface quality of grinding.

[0070] 5) Realize quantitative and uniform removal: By planning the required contact force according to the allowance and curvature radius at different positions of the welded extension area, quantitative and uniform removal is realized, further improving the quality and efficiency of grinding.

[0071] In summary, the technical solution of the present invention solves multiple technical problems in the prior art by introducing advanced parameters, algorithms and mathematical models, and has made remarkable technological progress, providing strong support for the adaptive measurement and grinding of the welded extension area of aeroengine blade tips. Brief Description of the Drawings

[0072] Figure 1 is a schematic diagram of hand-eye calibration by a standard ball provided by an embodiment of the present invention;

[0073] Figure 2 is a schematic diagram of welded extension measurement provided by an embodiment of the present invention;

[0074] Figure 3 is a schematic diagram of welded extension grinding provided by an embodiment of the present invention;

[0075] Figure 4 It is a schematic diagram of the quick-change device connecting the rigid-flexible coupling compliant actuator provided by the embodiment of the present invention;

[0076] Figure 5 It is a schematic diagram of the line laser measuring instrument provided by the embodiment of the present invention;

[0077] Figure 6 It is a flowchart of the adaptive measurement and grinding method for the tip welding and extension area of the aero-engine blade provided by the embodiment of the present invention;

[0078] Figure 7 It is a diagram of the tip welding area of a certain type of aero-engine blade provided by the embodiment of the present invention;

[0079] Figure 8 It is a schematic diagram of the process of measuring the welding and extension allowance at the tip of the aero-engine blade provided by the embodiment of the present invention;

[0080] Figure 9 It is a diagram of the grinding trajectory of the robot for welding and extending the tip of the aero-engine blade provided by the embodiment of the present invention;

[0081] Figure 10 It is a diagram of the adaptive measurement and grinding result of the tip welding area of a certain type of aero-engine blade provided by the embodiment of the present invention;

[0082] In the figure: 101, robot body; 102, actuator placement table; 103, rigid-flexible coupling compliant actuator; 104, belt grinder; 105, robot quick-change device; 106, line laser measuring instrument; 107, blade with tip welded and extended; 108, positioning fixture; 109, robot working turntable; 110, ceramic standard ball. Detailed implementation manners

[0083] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0084] Embodiment 1: Repair of a certain type of aero-engine blade

[0085] During the use of a certain type of aero-engine blade, wear and damage occur in the tip welding and extension area, and repair is required. By using the adaptive measurement and grinding method of the present invention, efficient and high-precision repair can be achieved, improving the service life and performance of the blade.

[0086] 1) Hand-eye calibration: Use the line laser measuring instrument to scan the fixed standard ball for hand-eye calibration, which only needs to be calibrated when used for the first time.

[0087] 2) Blade installation: Install the blade to be ground on the positioning fixture to ensure that the blade is firmly fixed within the working area of the robot.

[0088] 3) Blade measurement: Connect the line laser measuring instrument through the quick-change device, and scan and measure the blade according to the planned path to obtain the allowance and position of the welding extension area.

[0089] 4) Generation of rough grinding trajectory: Generate the rough grinding trajectory for the welding extension area at the blade tip according to the measured point cloud.

[0090] 5) Planning of rough grinding parameters: According to the material removal model of the low-grit sand belt, plan the contact force and the robot feed speed during rough grinding.

[0091] 6) Rough grinding process: The robot connects the rigid-flexible coupled compliant actuator through the quick-change device to perform rough grinding, and quantitatively removes most of the welding material.

[0092] 7) Re-measurement: The robot measures the allowance and position of the welding extension area again through the line laser measuring instrument.

[0093] 8) Generation of fine grinding trajectory: Generate the fine grinding trajectory for the welding extension area at the blade tip according to the measured point cloud.

[0094] 9) Planning of fine grinding parameters: According to the material removal model of the high-grit sand belt, plan the contact force and the robot feed speed during fine grinding.

[0095] 10) Fine grinding process: The robot connects the rigid-flexible coupled compliant actuator through the quick-change device to perform fine grinding to ensure a smooth transition between the extended area and the non-extended area.

[0096] 11) Final measurement: The robot finally measures through the line laser measuring instrument to ensure that the quality of the ground blade is qualified.

[0097] Example 2: Blade grinding during the major overhaul of an aeroengine

[0098] During the major overhaul of an aeroengine, the welding extension area at the blade tip needs to be ground to restore its working performance. By using the method of the present invention, the blade grinding work can be completed efficiently and accurately.

[0099] 1) Hand-eye calibration: Use the line laser measuring instrument to scan the fixed standard ball for hand-eye calibration, which only needs to be calibrated when used for the first time.

[0100] 2) Blade installation: Install the blade to be ground on the positioning fixture to ensure that the blade is firmly fixed within the working area of the robot.

[0101] 3) Blade measurement: Connect the line laser measuring instrument through the quick-change device, and scan and measure the blade according to the planned path to obtain the allowance and position of the welding extension area.

[0102] 4) Generation of rough grinding trajectory: Generate the rough grinding trajectory of the welding extension area at the blade tip according to the measured point cloud.

[0103] 5) Planning of rough grinding parameters: Plan the contact force and robot feed speed during rough grinding according to the material removal model of the low-grit sand belt.

[0104] 6) Rough grinding process: The robot connects the rigid-flexible coupled compliant actuator through the quick-change device for rough grinding to quantitatively remove most of the welding material.

[0105] 7) Re-measurement: The robot measures the allowance and position of the welding extension area again through the line laser measuring instrument.

[0106] 8) Generation of fine grinding trajectory: Generate the fine grinding trajectory of the welding extension area at the blade tip according to the measured point cloud.

[0107] 9) Planning of fine grinding parameters: Plan the contact force and robot feed speed during fine grinding according to the material removal model of the high-grit sand belt.

[0108] 10) Fine grinding process: The robot connects the rigid-flexible coupled compliant actuator through the quick-change device for fine grinding to ensure a smooth transition between the extended area and the non-extended area.

[0109] 11) Final measurement: The robot finally measures through the line laser measuring instrument to ensure that the quality of the ground blade is qualified.

[0110] The above embodiments use a robot and line laser measurement technology, combined with an adaptive planning method for rough grinding and fine grinding, to achieve efficient and high-precision blade grinding. This method can significantly improve the grinding efficiency, reduce manual operation errors, ensure the quality and performance of the ground blade, and is applicable to large-scale repair and remanufacturing of aeroengine blades.

[0111] As Figure 1 shown, a method for measuring the allowance of the welding extension area at the blade tip of an aeroengine blade and robot adaptive compliant grinding includes a robot body (101), an actuator placement table (102), a rigid-flexible coupled compliant actuator (103), a sanding machine (104), a robot quick-change device (105), a line laser measuring instrument (106), a blade with a welded extension at the tip (107), a positioning fixture (108), a robot working turntable (109), and a ceramic standard ball (110).

[0112] The robot body of a method for measuring the allowance of the tip welding and extension area of an aeroengine blade and robot adaptive compliant grinding is mainly responsible for the measuring and grinding trajectories. The actuator placement table is used for storing and positioning the tools at the end of the robot. The rigid-flexible coupled compliant actuator is responsible for controlling the grinding contact force. The belt grinder is responsible for grinding the extension area. The robot quick-change device is used for the quick replacement of the line laser and the rigid-flexible coupled compliant actuator. The line laser measuring instrument is used for measuring the welding and extension area and analyzing the allowance of the extension area. The positioning fixture is responsible for clamping and positioning the blade. The robot working turntable is the main working area of the robot. The ceramic standard ball is used for the hand-eye calibration of the robot and the line laser measuring instrument.

[0113] As Figure 1 shown, when the line laser measuring instrument is used for the first time, hand-eye calibration is required. The fixed standard ball is scanned in different postures for hand-eye calibration, and the hand-eye matrix is obtained by the least squares method. When used again, no secondary calibration is required.

[0114] As Figure 2 shown, the robot connects the line laser measuring instrument through the quick-change device and scans and measures according to the planned path. The measurement data can be converted into the data in the robot base coordinate system through the hand-eye matrix, and then.

[0115] As Figure 3 shown, the robot connects the rigid-flexible coupled actuator through the quick-change device and grinds according to the path generated by the measured point cloud.

[0116] As Figure 4 shown, a rigid-flexible coupled actuator is used, and its internal main structure is a series elastic actuator, which can ensure the contact force accuracy and compliance.

[0117] As Figure 5 shown, a line laser measuring instrument is used, which can quickly measure the welding and extension allowance of the blade.

[0118] As Figure 6 shown, further, the whole processing flow includes:

[0119] S1 The end of the robot connects the line laser measuring instrument through the quick-change device, and scans the fixed standard ball in different postures for hand-eye calibration. Calibration is only required for the first use. The specific principle is as follows:

[0120] The line laser scans a certain unknown cross-section of the standard ball to obtain an arc in the line laser measurement coordinate system, and the center coordinates of the circle are determined by arc fitting. Combining the radius R of the standard ball and the radius r of the fitted circle, the center coordinates of the ball in the line laser measurement coordinate system are established s P = s x s y s z] T , and the point P is in the robot base coordinate system b P, the robot end coordinate systeme P and the line laser measurement coordinate system s There is the following relationship for P:

[0121]

[0122] where and are the homogeneous transformation matrices from the robot base coordinate system to the end - effector coordinate system and from the robot end - effector coordinate system to the line laser measurement coordinate system respectively. By decomposing the homogeneous transformation matrix into a rotation matrix and a translation matrix, we have:

[0123]

[0124] where and are respectively 's rotation component and translation component, and are respectively 's rotation component and translation component.

[0125] Simplifying formula (12) gives:

[0126] At this time, measuring the center of the sphere P with n different poses can obtain the following formula:

[0127]

[0128] where 1 ≤ i ≤ n, i is the measurement serial number, and n is the number of measurement groups.

[0129] Taking the difference between any two different equations of formula (14) gives equations, and after simplification, we can get:

[0130]

[0131] Formula (15) is in the general form of a linear equation system AX = b, where A is matrix, where

[0132]

[0133] Generally Therefore, the least - squares method can be used to solve the hand - eye calibration matrix. Then:

[0134]

[0135] The operator manually installs the blade to be ground on the positioning fixture.

[0136] The S3 robot connects the line laser measuring instrument through a quick-change device, and scans and measures the blade according to the planned path to obtain the margin of the welding extension area and the position of the welding extension in the robot coordinate system.

[0137] S4 generates the grinding trajectory of the rough grinding of the blade tip welding extension of the blade according to the measured point cloud.

[0138] S5 plans the contact force and the robot feed speed during the rough grinding process according to the material removal model of the low-mesh (80#) abrasive belt.

[0139] S6 The robot connects the rigid-flexible coupled compliant actuator through a quick-change device to perform rough grinding and quantitatively remove most of the welding materials.

[0140] S7 The robot connects the line laser measuring instrument through a quick-change device, and measures the margin of the welding extension area and the position of the welding extension in the robot coordinate system again.

[0141] S8 generates the grinding trajectory of the fine grinding of the blade tip welding extension of the blade according to the measured point cloud.

[0142] S9 plans the contact force and the robot feed speed during the fine grinding process according to the material removal model of the high-mesh (800#) abrasive belt.

[0143] S10 The robot connects the rigid-flexible coupled compliant actuator through a quick-change device to perform fine grinding to ensure a smooth transition between the extension area and the non-extension area.

[0144] S11 The robot connects the line laser measuring instrument through a quick-change device to finally detect and ensure that the quality of the ground blade is qualified.

[0145] Among them, in step S3, first, the voxel grid downsampling is used to reduce the point cloud density and obtain a uniform point cloud distribution, and the Gaussian filtering is used to preprocess the point cloud data. Then, the welding extension area is identified through the curvature mutation detection and the rest of the non-extension area is segmented. The non-extension area is fitted and extended to the extension area as the theoretical surface. Then, the height data of the point cloud in the welding extension area is subtracted from the height of the theoretical surface to obtain the margin of the welding extension.

[0146] As Figure 6 shown, in step S4, the robot grinding trajectory converts the point cloud of the welding area identified in step S3 into the robot base coordinate system data through the hand-eye calibration matrix in S1, and then generates the motion trajectory in the base coordinate system from the center line of the welding extension area.

[0147] Furthermore, the material removal models in steps S5 and S9 adopt the following form:

[0148]

[0149] where h is the removal depth, k his the material removal coefficient, which can be calibrated through experiments, V r is the speed of the abrasive belt machine, V t is the tangential feed speed of the robot, F is the grinding contact force, R1 is the radius of the contact wheel of the abrasive belt machine, and R2 is the radius of curvature of the workpiece contact point.

[0150] Furthermore, with a constant robot feed speed, according to the welding elongation margin h j and the radius of curvature R 2j the required contact force is planned to achieve quantitative and uniform removal. Among them:

[0151]

[0152] The application embodiment of the present invention provides a computer device, which includes a memory and a processor. The memory stores a computer program. When the computer program is executed by the processor, the processor executes the steps of robot hand-eye calibration, grinding path generation and grinding process planning method.

[0153] The application embodiment of the present invention provides a computer-readable storage medium, storing a computer program. When the computer program is executed by the processor, the processor executes the steps of robot hand-eye calibration, grinding path generation and grinding process planning method.

[0154] The application embodiment of the present invention provides an information data processing terminal, which includes a line laser measurement and grinding process planning system.

[0155] The present invention is specifically applied to a welding elongation area at the tip of a turbine blade of an aeroengine, such as Figure 7 shown. The tip part of the blade concave area has laser casting welding elongation, and there is no welding at the blade convex part. Only the welding elongation at the tip part of the blade concave area needs to be ground.

[0156] As Figure 8 shown is the method for processing the point cloud measured by the line laser measuring instrument obtained in step S3. First, the initial point cloud data is obtained. The tip welding elongation area is segmented by curvature mutation detection, and then the non-elongation area is fitted and extended to the elongation area as the theoretical surface. Then, the height data of the point cloud in the welding elongation area is subtracted from the height of the theoretical surface to obtain the margin of the welding elongation, Figure 8 and the bottommost is the margin value corresponding to the upper cut line.

[0157] As Figure 9 shown is the grinding trajectory generated in the ABB simulation software RobotStudio in steps S4 and S8.

[0158] As Figure 10The following shows the effect after grinding of the present invention. The redundant materials of the welded extension are removed, and a smooth transition is achieved on the surface.

[0159] It should be noted that the embodiments of the present invention can be implemented through hardware, software, or a combination of software and hardware. The hardware part can be implemented using dedicated logic; the software part can be stored in a memory and executed by an appropriate instruction execution system, such as a microprocessor or dedicated design hardware. Those of ordinary skill in the art can understand that the above-mentioned devices and methods can be implemented using computer-executable instructions and / or included in processor control code, for example, such code is provided on a carrier medium such as a disk, CD, or DVD-ROM, a programmable memory such as read-only memory (firmware), or a data carrier such as an optical or electronic signal carrier. The devices and their modules of the present invention can be implemented by hardware circuits of programmable hardware devices such as very large scale integrated circuits or gate arrays, semiconductors such as logic chips, transistors, etc., or field programmable gate arrays, programmable logic devices, etc., can also be implemented by software executed by various types of processors, or can be implemented by a combination of the above hardware circuits and software such as firmware.

[0160] As mentioned above, the above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be covered by the protection scope of the present invention.

Claims

1. An adaptive measurement and grinding method for the tip welding extension area of an aero-engine blade, using an adaptive measurement and grinding system for the tip welding extension area of an aero-engine blade, characterized in that Including: S1, the end of the robot uses a quick-change device to connect a line laser measuring instrument, and scans a fixed standard ball in different postures for hand-eye calibration, which is only required for the first use. S2, manually install the blade to be ground on the positioning fixture. S3, the robot uses a quick-change device to connect a line laser measuring instrument, and scans and measures the blade according to the planned path to obtain the margin of the welding extension area and the position of the welding extension area in the robot base coordinate system. S4, generate the grinding trajectory of the robot rough grinding for the blade tip welding extension area according to the measured point cloud. S5, plan the contact force and the robot feed speed during the rough grinding process according to the material removal model of the 80# abrasive belt. S6, the robot uses a quick-change device to connect a rigid-flexible coupled compliant actuator for rough grinding to quantitatively remove most of the welding materials. S7, the robot uses a quick-change device to connect a line laser measuring instrument, and measures the margin of the welding extension area and the position of the welding extension area in the robot coordinate system again. S8, generate the grinding trajectory of the robot fine grinding for the blade tip welding extension area according to the measured point cloud. S9, plan the contact force and the robot feed speed during the fine grinding process according to the material removal model of the 800# abrasive belt. S10, the robot uses a quick-change device to connect a rigid-flexible coupled compliant actuator for fine grinding to ensure a smooth transition between the extended area and the non-extended area. S11, the robot uses a quick-change device to connect a line laser measuring instrument for final measurement to ensure that the quality of the ground blade is qualified. The adaptive measurement and grinding system for the blade tip welding extension area of an aero-engine includes: A robot body with multi-degree-of-freedom motion ability. A quick-change device installed at the end of the robot for connecting different tools. A line laser measuring instrument connected to the end of the robot through a quick-change device for scanning the blade and generating point cloud data. A rigid-flexible coupled compliant actuator connected to the end of the robot through a quick-change device for rough grinding and fine grinding of the blade welding extension area. A positioning fixture for fixing the blade to be ground. A controller including a Beckhoff CX8200 main controller for processing measurement data, planning grinding paths, and controlling the robot to perform grinding tasks. A belt grinder equipped with abrasive belts of different meshes for rough grinding and fine grinding respectively. A standard ball for hand-eye calibration fixed on the workbench. The end of the robot uses a quick-change device to connect a line laser measuring instrument and scans the fixed standard ball in different postures for hand-eye calibration, which is only required for the first use. In step S3, first reduce the point cloud density by voxel grid downsampling and obtain a uniform point cloud distribution, and preprocess the point cloud data using Gaussian filtering; then identify the welding extension area through curvature mutation detection and segment the remaining non-extension area, fit and extend the non-extension area to the extension area as the theoretical surface, and then subtract the height of the theoretical surface from the point cloud data of the welding extension area to obtain the margin of the welding extension area.

2. The adaptive measurement and grinding method for the tip welding and extension area of an aeroengine blade as described in claim 1, wherein The controller further includes: A control algorithm and path planning module for generating the grinding trajectory of the blade tip welding extension area according to the measured point cloud, and planning the contact force and the robot feed speed during the grinding process according to the material removal models of abrasive belts of different meshes.

3. The adaptive measurement and grinding method for the tip welding and lengthening area of an aeroengine blade according to claim 1, characterized in that The specific principle of S1 is as follows: The line laser scans the cross-section of the standard sphere to obtain an arc in the line laser measurement coordinate system, and the center coordinates of the circle are determined by arc fitting; combining the radius R of the standard sphere and the radius r of the fitted circle, the center coordinates of the sphere in the line laser measurement coordinate system are established s P = s x s y s z] T , and the point P is in the robot base coordinate system b P, the robot end coordinate system e P and the line laser measurement coordinate system s P has the following relationship: where and are the homogeneous transformation matrices from the robot base coordinate system to the robot end coordinate system and from the robot end coordinate system to the line laser measurement coordinate system respectively. Decomposing the homogeneous transformation matrix into a rotation matrix and a translation matrix, we have: wherein and are respectively the rotational component and translational component of, and are respectively the rotational component and translational component of; Simplifying formula (3) gives: At this time, measuring the center of the ball P with n different poses can obtain the following formula: wherein 1 ≤ i ≤ n, where i is the measurement serial number and n is the number of measurement groups; Taking the difference between any two different equations of formula (5) gives equations, which after simplification gives: Equation (6) is in the general form of a linear equation system AX = b, where A is a matrix, and Therefore, the hand-eye calibration matrix can be solved by the least squares method, so that: 。 4. The adaptive measurement and grinding method for the tip welding and extending area of an aero-engine blade as claimed in claim 1, wherein In step S4, the robot grinding trajectory converts the point cloud of the welding area identified in step S3 into robot base coordinate system data through the hand-eye calibration matrix in S1, and then generates a motion trajectory in the base coordinate system from the center line of the welding extension area.

5. The adaptive measurement and grinding method for the tip welding and extension area of an aeroengine blade as described in claim 1, characterized in that The material removal models in steps S5 and S9 adopt the following form: where h is the removal depth, k h is the material removal coefficient that can be calibrated through experiments, V r is the speed of the belt grinder, V t is the tangential feed speed of the robot, F is the grinding contact force, R1 is the radius of the contact wheel of the belt grinder, and R2 is the radius of curvature of the workpiece contact point.

6. The adaptive measurement and grinding method for the tip welding and extension area of an aeroengine blade as described in claim 1, characterized in that, With a constant robot feed speed, the required contact force is planned according to the welding elongation allowance h at different positions in the welding elongation area j and the radius of curvature R 2j to achieve quantitative and uniform removal. R1 is the radius of the contact wheel of the belt sander, R2 is the radius of curvature of the workpiece contact point, and k h is the material removal coefficient that can be calibrated through experiments, V r is the rotational speed of the belt sander, V t is the tangential feed speed of the robot, and F j is the contact force, where: 。

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