Five-axis machine tool line laser in-situ measurement and hole site self-adaptive alignment method and system
By using a five-axis machine tool line laser sensor to perform three scan measurements, the problems of difficulty in aligning the normal direction of countersunk hole drilling and out-of-tolerance hole diameter were solved, realizing online adaptive alignment and precise control of the hole position.
Patent Information
- Application Number
- CN202511154540.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-18
- Publication Date
- 2025-11-25
- Estimated Expiration
- 2045-08-18
AI Technical Summary
In the aircraft manufacturing process, the drilling direction and the diameter of the countersunk hole may deviate, resulting in an uneven external profile, which increases flight drag and may cause structural failure. Existing technologies make it difficult to achieve adaptive alignment and online detection of the hole position.
A five-axis machine tool line laser sensor is used for three-scan measurement. The line laser sensor detects the drilling normal and adjusts the coordinate system to identify the hole diameter and calculate the depth compensation, thereby realizing online measurement and adaptive alignment of the hole position.
It achieves precise control of the drilling normal and accurate detection of the hole diameter, solving the problems of difficult hole alignment and easy hole diameter deviation, and realizes non-contact online measurement and automatic telescopic protection.
Smart Images

Figure CN121004491A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of hole alignment, in particular to a five-axis machine tool line laser in-situ measurement and hole self-adaptive alignment method and system. BACKGROUND
[0002] In the process of aircraft manufacturing, the precision of countersunk hole machining has a direct impact on the structural safety and aerodynamic performance of the aircraft. In order to ensure that the fasteners and the surface of the aircraft skin and structural parts are flush and fit, forming a continuous and smooth aerodynamic shape, countersunk hole machining puts forward extremely strict precision requirements on the size of the hole diameter. If there is a size deviation between the drilling direction and the hole diameter, not only will it destroy the flatness of the external contour, leading to a significant increase in flight resistance, but it may also cause local stress concentration, thereby burying the risk of structural failure. However, most aircraft structural parts are typical thin-walled parts, which are prone to deformation during machining, thereby causing the drilling direction and the hole diameter to be out of tolerance. Therefore, the drilling direction and the hole diameter detection and control method is particularly important.
[0003] Patent document (application number: 202411607576.4) discloses a device and method for controlling the depth of engine suspension fastener hole countersinking, which modifies the mechanical tool holder and adds a position sensor to achieve accurate control of the countersinking stroke, realizing automatic control of the countersink depth of assembled parts and parts. However, this patent does not achieve self-adaptive alignment of the hole position. Patent document (application number: 202410370560.X) discloses an in-situ measurement method and device for aircraft skin countersink hole depth, which realizes drilling normal adjustment through a detachable in-situ measurement device, but lacks an online detection mechanism for hole diameter size.
[0004] Patent application document CN117906496A discloses a hole position precision measurement jig and manufacturing method, detection and correction compensation method, including a jig body, the jig body is a transparent or translucent piece with photosensitive color-changing characteristics, the jig body is provided with a positioning disc for determining a coordinate system; the jig body is provided with an icon unit, the icon unit is composed of a plurality of icon combinations, the icon combination includes a reference icon, the center of the reference icon is aligned with the center hole of the laser drilling to be detected, the reference icon is provided with a ring-shaped distribution of offset icons, the offset icons correspond to the number of ring-shaped holes of the laser drilling to be detected, after the reference icon of the icon combination is aligned with the center hole of the laser drilling to be detected, there is a positional offset between the offset icons of the icon combination and the ring-shaped holes of the laser drilling to be detected, and the offset direction and offset value of the offset icons of the jig body are not completely the same. However, this patent cannot completely solve the existing technical problems and cannot meet the needs of the present application. SUMMARY
[0005] In view of the defects in the prior art, the present application aims to provide a five-axis machine tool line laser in-situ measurement and hole self-adaptive alignment method and system.
[0006] The five-axis machine tool line laser in-situ measurement and hole self-adaptive alignment method provided by the application comprises:
[0007] Step 1: First scanning measurement of the workpiece hole region is performed by the line laser sensor, drilling normal is calculated based on the measurement data, and the coordinate system rotation angle is output;
[0008] Step 2: The machine tool coordinate system is adjusted according to the coordinate system rotation angle, drilling and counterbore rough machining is performed, and a machining allowance is reserved;
[0009] Step 3: Second scanning measurement of the rough-machined hole is performed by the line laser sensor, the current hole diameter is identified, and the depth compensation amount is calculated;
[0010] Step 4: The tool length parameter is adjusted according to the depth compensation amount, and counterbore fine machining is performed;
[0011] Step 5: Third scanning measurement is performed by the line laser sensor, and a final hole diameter detection report is output;
[0012] Preferably, the line laser sensor is driven by a pneumatic cylinder to move along the guide rail to the measurement position.
[0013] Preferably, the step 1 comprises: controlling the machine tool to move along the scanning direction, acquiring line laser profile data of the hole and the circular hole region, converting laser coordinate system LCS data into three-dimensional point cloud data of the workpiece coordinate system WCS through homogeneous coordinate transformation, and the expression is:
[0014]
[0015] wherein, are coordinate points in the workpiece coordinate system and the laser coordinate system respectively, are homogeneous coordinate transformation matrices from the laser coordinate system to the tool coordinate system and from the tool coordinate system to the workpiece coordinate system respectively;
[0016] The point cloud around the hole is plane-fitted, and after screening outliers, the normal vector is obtained by re-fitting.
[0017] Preferably, the plane fitting comprises: preliminarily fitting a plane equation Ax+By+Cz+D=0, calculating the distance from the point cloud to the roughly-fitted plane and eliminating outliers, fitting the plane again and outputting the normal vector, and calculating the rotation angle around the X-axis and the Y-axis according to the deviation of the target normal and the current normal, wherein A, B, and C represent three components of the normal vector of the fitted plane, (x, y, z) is the coordinate of a space point, and D is the directed distance from the origin to the plane.
[0018] Preferably, the identification of the current bore diameter in step 3 comprises: extracting the plane point cloud with a projection distance greater than 1.1 times the theoretical radius from the hole center, fitting the plane equation Ax+By+Cz+D=0, extracting the conical hole point cloud with a projection distance less than 0.9 times the theoretical radius from the hole center, dividing the conical hole point cloud into left and right groups according to the relative position of the center, fitting the spatial straight line equation respectively, and taking the intersection of the spatial straight line and the plane as the conical hole edge point. Fit the edge point into a spatial circle, and the diameter is the current bore diameter d1.
[0019] Preferably, the calculation of the depth compensation amount in step 3 comprises: according to the current bore diameter d1, and the final bore diameter d2 set by the program, and the given tool angle Calculate the depth compensation amount Δd, the expression is:
[0020]
[0021] Where, θ is the hole angle.
[0022] The five-axis machine tool line laser in-situ measurement and hole position self-adaptive alignment system provided by the application comprises:
[0023] Module M1: drive the line laser sensor to perform first scanning measurement on the workpiece bore hole area, calculate the drilling normal based on the measurement data, and output the coordinate system rotation angle;
[0024] Module M2: adjust the machine tool coordinate system according to the coordinate system rotation angle, perform drilling and counterbore rough machining and reserve machining allowance;
[0025] Module M3: drive the line laser sensor to perform second scanning measurement on the rough machined bore hole, identify the current bore diameter and calculate the depth compensation amount;
[0026] Module M4: adjust the tool length parameter according to the depth compensation amount, and perform counterbore finishing machining;
[0027] Module M5: drive the line laser sensor to perform third scanning measurement, and output the final detection report of the bore diameter;
[0028] Wherein, the line laser sensor is driven to move to the measurement position along the guide rail by the air cylinder.
[0029] Preferably, the module M1 comprises: controlling the machine tool to move along the scanning direction, obtaining the line laser profile data of the bore hole and the circular hole area, converting the laser coordinate system LCS data into three-dimensional point cloud data of the workpiece coordinate system WCS through homogeneous coordinate transformation, and the expression is:
[0030]
[0031] Wherein, are the coordinate points in the workpiece coordinate system and the laser coordinate system respectively, These are the homogeneous coordinate transformation matrices from the laser coordinate system to the tool coordinate system and from the tool coordinate system to the workpiece coordinate system, respectively.
[0032] Planar fitting was performed on the point cloud around the pores, and after outliers were filtered out, the normal vector was obtained by refitting.
[0033] Preferably, the plane fitting includes: initially fitting the plane equation Ax+By+Cz+D=0, calculating the distance from the point cloud to the coarsely fitted plane and removing outliers, fitting the plane again and outputting the normal vector, and calculating the rotation angle around the X-axis and Y-axis based on the deviation between the target normal and the current normal, where A, B, and C represent the three components of the normal vector of the fitted plane, (x,y,z) are the coordinates of the spatial point, and D is the directed distance from the origin to the plane.
[0034] Preferably, the identification of the current hole diameter in module M3 includes: extracting planar point clouds with a distance from the hole center projection distance greater than 1.1 times the theoretical radius, fitting the plane equation Ax+By+Cz+D=0, extracting conical hole point clouds with a distance from the hole center projection distance less than 0.9 times the theoretical radius, dividing the conical hole point clouds into left and right groups according to the relative position of the center of the circle, fitting the spatial straight line equations respectively, taking the intersection of the spatial straight line and the plane as the edge point of the conical hole, fitting the edge point into a spatial circle, and the diameter of the circle is the current hole diameter d1.
[0035] Preferably, the calculated depth compensation amount in module M3 includes: a given tool angle based on the current notch diameter d1 and the final notch diameter d2 set by the program. The depth compensation amount Δd is calculated using the following expression:
[0036]
[0037] Where θ is the pit angle.
[0038] Compared with the prior art, the present invention has the following beneficial effects:
[0039] (1) This invention uses a line laser sensor to detect the drilling normal and modify the rotation angle of the coordinate system frame, which solves the problem of difficult drilling normal alignment in countersunk holes and achieves precise control of the drilling normal; it also uses a line laser sensor to detect the countersunk diameter and modify the tool length compensation, which solves the problem of the countersunk diameter easily exceeding the tolerance and achieves precise control of the countersunk diameter.
[0040] (2) By performing three scan measurements using a non-contact line laser in-situ measurement device, the problem of traditional methods requiring tool disassembly and being unable to detect the hole diameter online is solved, thus realizing online measurement and adaptive alignment of the hole position;
[0041] (3) By using a cylinder to drive the linear laser sensor to move along the guide rail to the measurement position, the problems of sensor positioning accuracy and protection are solved, and the automatic extension and retraction protection of the in-situ measurement device is realized.
[0042] (4) The laser coordinate system data is converted into the workpiece coordinate system point cloud by homogeneous coordinate transformation, which solves the problem of multi-coordinate system data fusion and realizes the unification of measurement data and processing datum. Attached Figure Description
[0043] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:
[0044] Figure 1 This is a schematic diagram of the in-situ measuring device of the present invention;
[0045] Figure 2 This is a schematic diagram of line laser normal measurement;
[0046] Figure 3 This is a schematic diagram of a line laser data conversion device;
[0047] Figure 4 Here is a flowchart for extracting the plane normal.
[0048] Figure 5 A cross-sectional view of point cloud data;
[0049] Figure 6 This is a schematic diagram for calculating depth compensation.
[0050] The diagram shows: 1-device housing, 2-wireless access point, 3-line laser controller, 4-line laser sensor, 5-guide rail, 6-cylinder, 7-cable, 8-recess, 9-round hole, 10-tool, 11-connector, 12-workpiece, Δd is the depth compensation amount, d1 is the current recess diameter, and d2 is the final recess diameter. θ is the tool angle, and θ is the hole angle. Detailed Implementation
[0051] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.
[0052] Example 1
[0053] like Figure 1The in-situ measurement device of this invention is installed on the side of the spindle of a five-axis machine tool. The device includes a control section and a measurement section. The control section consists of a device housing 1, a wireless access point 2, and a line laser controller 3. The line laser controller 3 is connected to a line laser sensor 4 via a data cable and is used to receive contour data collected by the sensor. The wireless access point 2 is connected to the line laser controller 3 via a wired network port and simultaneously interacts with a host computer via a wireless network to achieve real-time transmission of measurement data. The device housing 1 provides overall protection and sealing, and internally fixes the controller and the wireless access point.
[0054] The measurement section consists of a line laser sensor 4, a guide rail 5, a cylinder 6, and a cable 7. It is used to acquire workpiece contour data. The line laser sensor 4 is fixed on the slider of the cylinder 6, which moves linearly along the measurement direction via the guide rail 5. The cylinder 6 is driven by control signals from the control section, allowing it to push the sensor to a designated measurement position or retract it to a protective position. The cable 7 provides the drive signal and air supply to the cylinder, as well as power and data transmission channels for the line laser sensor. During measurement, the cylinder 6 pushes the line laser sensor 4 to the designated position for in-situ measurement. In the in-situ hole measurement and hole position adaptive alignment method, three scanning measurements are performed. The first is a rapid scanning measurement to determine the drilling direction of the hole. By rotating the coordinate system frame, the machine tool is controlled to perform drilling and rough countersinking along the normal direction. After rough countersinking, the hole position is scanned again at a reduced speed. The diameter of the current hole is obtained by extracting the measurement point cloud, and the depth compensation is determined based on the current hole diameter. Finishing is then performed. Finally, a line laser scanning measurement is performed again to generate a measurement report.
[0055] Detailed steps:
[0056] Step 1: Line laser normal measurement;
[0057] Step 1.1: Collect measurement data: such as Figure 2 The horizontal lines represent single-frame measurement data of the linear laser. By controlling the machine tool to perform scanning measurement motion along the scanning direction to cover the area where the dimple 8 and the round hole 9 are located, the contour measurement data of the area where the dimple is located is obtained.
[0058] Step 1.2, Linear Laser Data Conversion:
[0059] like Figure 3The line laser sensor 4 is connected to the machine tool spindle via connector 11, and the workpiece 12 is mounted on the worktable. Line laser scanning data is acquired based on the line laser coordinate system (LCS), while the tool coordinate system (TCS) is located on the machine tool spindle. By offsetting the tool 10, the tool coordinate system can be positioned on connector 11, while the workpiece coordinate system (WCS) rests on the workpiece. Since the machine tool's programming and machining are based on the WCS, it is necessary to convert the measurement data from the laser coordinate system to the workpiece coordinate system to form three-dimensional point cloud data.
[0060]
[0061] in, These are the coordinate points in the workpiece coordinate system and the laser coordinate system, respectively. These are the homogeneous coordinate transformation matrices from the laser coordinate system to the tool coordinate system and from the tool coordinate system to the workpiece coordinate system, respectively.
[0062] Step 1.3, Extraction of Plane Normal:
[0063] like Figure 4 After obtaining the 3D point cloud data, the rotation angle of the coordinate system is calculated to ensure drilling along the workpiece's normal direction during subsequent machining. First, the point cloud data surrounding the hole is subjected to preliminary plane fitting to obtain the planar parameters of that area. Then, the distance from the surrounding point cloud to the coarsely fitted plane is calculated, outliers are filtered out based on the distance, and the plane is fitted again to output the normal direction for the hole location. The rotation amount of the coordinate system, i.e., the rotation angle around the X and Y axes, is calculated from the current normal and the target normal. Finally, the two rotation angles are output to the Siemens machine tool's dedicated coordinate system rotation loop command to control the coordinate system rotation.
[0064] Step 2: Drilling and countersinking rough machining;
[0065] The machine tool rotates the coordinate system according to the rotation angle given by the CYCLE800 coordinate system rotation command. The machine tool performs drilling and preliminary countersinking along the actual normal of the workpiece, leaving machining allowance.
[0066] Step 3: Wire laser aperture detection;
[0067] To obtain the current diameter of the notch in the current processing state, the scanning measurement speed is reduced. The notch area is measured again according to step 1.1 to obtain the notch contour measurement data. The laser data is then converted according to step 1.2. Finally, the current notch diameter is calculated and the depth compensation amount is output.
[0068] Step 3.1, Dig Diameter Identification: The input for the dimple diameter identification process is the center position of the dimple and the theoretical diameter of the dimple. The specific process is as follows:
[0069] Step 3.1.1: Extract planar point cloud data. All laser data is converted into point cloud data. Calculate the projection distance from all point clouds to the hole center. Only retain point clouds with a distance greater than 1.1 times the radius, thus filtering out the conical point cloud. Figure 5 The planar point cloud is shown, and the plane equation is obtained by fitting the planar point cloud:
[0070] Ax + By + Cz + D = 0
[0071] Step 3.1.2, as follows Figure 5 The image shows a single frame of laser data. The point cloud of the conical hole is extracted according to the distance to the center of the hole. Only the point cloud with a projection distance from the center of the hole less than 0.9 times the radius is retained as the point cloud of the conical hole.
[0072] Step 3.1.3: According to the relative position of the cone hole point cloud and the center of the circle, divide it into two cone surface point clouds, left and right. Fit the two cone surface point clouds to obtain two spatial straight line equations. Record the intersection points of the spatial straight line equations and the plane equations as the edge intersection points of the cone hole.
[0073] Step 3.1.4: Repeat steps 3.1.2 and 3.1.3 to obtain multiple edge intersection points. Fit the edge intersection points into a spatial circle and output the diameter of the spatial circle as the dimple diameter.
[0074] Step 3.2, Calculation of depth compensation;
[0075] like Figure 6 Based on the identified current notch diameter d1 and the final notch diameter d2 set by the program, the given tool angle Calculate the depth compensation amount Δd:
[0076] Hole angle θ:
[0077]
[0078] Step 4: Refining the countersink;
[0079] Based on the depth compensation amount Δd, the software system outputs the depth compensation amount to the CNC system via the OPCUA protocol, adjusts the tool length of the CNC system, and when the CNC machine tool executes the denting finishing CNC program, it calls the tool length parameter of the CNC system, which is equivalent to adjusting the machining depth during denting finishing, thereby improving the machining accuracy of the dent.
[0080] Step 5: Final detection of the laser aperture;
[0081] Perform laser scanning measurement again, and after obtaining laser data, convert it into three-dimensional point cloud data. Repeat the 3.1 pore diameter recognition process and output a pore diameter measurement report.
[0082] Example 2
[0083] This invention also provides a five-axis machine tool line laser in-situ measurement and hole position adaptive alignment system. The five-axis machine tool line laser in-situ measurement and hole position adaptive alignment system can be implemented by executing the process steps of the five-axis machine tool line laser in-situ measurement and hole position adaptive alignment method. That is, those skilled in the art can understand the five-axis machine tool line laser in-situ measurement and hole position adaptive alignment method as a preferred embodiment of the five-axis machine tool line laser in-situ measurement and hole position adaptive alignment system.
[0084] The system includes: Module M1: drives the line laser sensor to perform a first scan measurement of the workpiece's recessed area, calculates the drilling normal based on the measurement data, and outputs the coordinate system rotation angle; Module M2: adjusts the machine tool coordinate system according to the coordinate system rotation angle, performs rough drilling and countersinking, and reserves machining allowance; Module M3: drives the line laser sensor to perform a second scan measurement of the rough-machined recess, identifies the current recess diameter, and calculates the depth compensation amount; Module M4: adjusts the tool length parameter according to the depth compensation amount, and performs countersinking finishing; Module M5: drives the line laser sensor to perform a third scan measurement and outputs a final recess diameter detection report; wherein, the line laser sensor is driven by a cylinder to move along the guide rail to the measurement position.
[0085] The module M1 includes: controlling the machine tool to move along the scanning direction, acquiring line laser contour data of the recessed and circular hole regions, and converting the laser coordinate system (LCS) data into three-dimensional point cloud data of the workpiece coordinate system (WCS) through homogeneous coordinate transformation, expressed as:
[0086]
[0087] in, These are the coordinate points in the workpiece coordinate system and the laser coordinate system, respectively. These are the homogeneous coordinate transformation matrices from the laser coordinate system to the tool coordinate system and from the tool coordinate system to the workpiece coordinate system, respectively.
[0088] Planar fitting was performed on the point cloud around the pores, and after outliers were filtered out, the normal vector was obtained by refitting.
[0089] The plane fitting includes: initially fitting the plane equation Ax+By+Cz+D=0, calculating the distance from the point cloud to the coarsely fitted plane and removing outliers, fitting the plane again and outputting the normal vector, and calculating the rotation angles around the X and Y axes based on the deviation between the target normal and the current normal. Here, A, B, and C represent the three components of the normal vector of the fitted plane, (x,y,z) are the coordinates of the spatial point, and D is the directed distance from the origin to the plane.
[0090] The identification of the current hole diameter in module M3 includes: extracting planar point clouds at a distance greater than 1.1 times the theoretical radius from the hole center projection, fitting the plane equation Ax+By+Cz+D=0, extracting conical hole point clouds at a distance less than 0.9 times the theoretical radius from the hole center projection, dividing the conical hole point clouds into left and right groups according to the relative position of the center of the circle, fitting the spatial straight line equations for each group, finding the intersection of the spatial straight line and the plane as the edge points of the conical hole, fitting the edge points into a spatial circle, and the diameter of the circle is the current hole diameter d1.
[0091] The calculated depth compensation in module M3 includes: based on the current notch diameter d1 and the final notch diameter d2 set by the program, the given tool angle. The depth compensation amount Δd is calculated using the following expression:
[0092]
[0093] Where θ is the pit angle.
[0094] In the description of this application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.
[0095] Those skilled in the art will understand that, in addition to implementing the system, apparatus, and their modules provided by this invention in purely computer-readable program code, the same program can be implemented in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, and embedded microcontrollers by logically programming the method steps. Therefore, the system, apparatus, and their modules provided by this invention can be considered a hardware component, and the modules included therein for implementing various programs can also be considered structures within the hardware component; alternatively, modules for implementing various functions can be considered both software programs implementing the method and structures within the hardware component.
[0096] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.
Claims
1. A method for in-situ measurement and adaptive hole alignment using line laser on a five-axis machine tool, characterized in that, include: Step 1: Perform the first scan measurement of the workpiece hole area using a line laser sensor, calculate the drilling normal based on the measurement data, and output the coordinate system rotation angle; Step 2: Adjust the machine tool coordinate system according to the rotation angle of the coordinate system, perform rough machining of drilling and countersinking, and reserve machining allowance; Step 3: Perform a second scan measurement on the rough-machined hole using a line laser sensor to identify the current hole diameter and calculate the depth compensation amount; Step 4: Adjust the tool length parameters according to the depth compensation amount and perform countersinking finishing; Step 5: Perform a third scan measurement using a line laser sensor and output the final detection report for the dimple diameter; The line laser sensor is moved to the measurement position along the guide rail by a cylinder.
2. The five-axis machine tool line laser in-situ measurement and hole position adaptive alignment method according to claim 1, characterized in that, Step 1 includes: controlling the machine tool to move along the scanning direction, acquiring the line laser contour data of the recessed and circular hole regions, and converting the laser coordinate system (LCS) data into three-dimensional point cloud data of the workpiece coordinate system (WCS) through homogeneous coordinate transformation, expressed as: in, These are the coordinate points in the workpiece coordinate system and the laser coordinate system, respectively. These are the homogeneous coordinate transformation matrices from the laser coordinate system to the tool coordinate system and from the tool coordinate system to the workpiece coordinate system, respectively. Planar fitting was performed on the point cloud around the pores, and after outliers were filtered out, the normal vector was obtained by refitting.
3. The five-axis machine tool line laser in-situ measurement and hole position adaptive alignment method according to claim 2, characterized in that, The plane fitting includes: initially fitting the plane equation Ax+By+Cz+D=0, calculating the distance from the point cloud to the coarsely fitted plane and removing outliers, fitting the plane again and outputting the normal vector, and calculating the rotation angles around the X and Y axes based on the deviation between the target normal and the current normal. Here, A, B, and C represent the three components of the normal vector of the fitted plane, (x,y,z) are the coordinates of the spatial point, and D is the directed distance from the origin to the plane.
4. The five-axis machine tool line laser in-situ measurement and hole position adaptive alignment method according to claim 3, characterized in that, The identification of the current hole diameter in step 3 includes: extracting planar point clouds at a distance greater than 1.1 times the theoretical radius from the hole center projection, fitting the plane equation Ax+By+Cz+D=0, extracting conical hole point clouds at a distance less than 0.9 times the theoretical radius from the hole center projection, dividing the conical hole point clouds into left and right groups according to the relative position of the circle centers, fitting the spatial straight line equations for each group, finding the intersection points of the spatial straight lines and the plane as the edge points of the conical holes, fitting the edge points into a spatial circle, and the diameter of the circle is the current hole diameter d1.
5. The five-axis machine tool line laser in-situ measurement and hole position adaptive alignment method according to claim 4, characterized in that, The calculation of depth compensation in step 3 includes: based on the current notch diameter d1 and the final notch diameter d2 set by the program, the given tool angle. The depth compensation amount Δd is calculated using the following expression: Where θ is the pit angle.
6. A five-axis machine tool line laser in-situ measurement and hole position adaptive alignment system, characterized in that, include: Module M1: Drives the line laser sensor to perform the first scan measurement of the workpiece hole area, calculates the drilling normal based on the measurement data and outputs the coordinate system rotation angle; Module M2: Adjusts the machine tool coordinate system according to the rotation angle of the coordinate system, performs rough machining of drilling and countersinking, and reserves machining allowance; Module M3: Drives the line laser sensor to perform a second scan measurement on the rough-machined hole, identify the current hole diameter and calculate the depth compensation amount; Module M4: Adjusts the tool length parameters according to the depth compensation amount to perform countersink finishing; Module M5: Drives the line laser sensor to perform a third scan measurement and outputs the final detection report of the dimple diameter; The line laser sensor is moved to the measurement position along the guide rail by a cylinder.
7. The five-axis machine tool line laser in-situ measurement and hole position adaptive alignment system according to claim 6, characterized in that, The module M1 includes: controlling the machine tool to move along the scanning direction, acquiring line laser contour data of the recessed and circular hole regions, and converting the laser coordinate system (LCS) data into three-dimensional point cloud data of the workpiece coordinate system (WCS) through homogeneous coordinate transformation, expressed as: in, These are the coordinate points in the workpiece coordinate system and the laser coordinate system, respectively. These are the homogeneous coordinate transformation matrices from the laser coordinate system to the tool coordinate system and from the tool coordinate system to the workpiece coordinate system, respectively. Planar fitting was performed on the point cloud around the pores, and after outliers were filtered out, the normal vector was obtained by refitting.
8. The five-axis machine tool line laser in-situ measurement and hole position adaptive alignment system according to claim 7, characterized in that, The plane fitting includes: initially fitting the plane equation Ax+By+Cz+D=0, calculating the distance from the point cloud to the coarsely fitted plane and removing outliers, fitting the plane again and outputting the normal vector, and calculating the rotation angles around the X and Y axes based on the deviation between the target normal and the current normal. Here, A, B, and C represent the three components of the normal vector of the fitted plane, (x,y,z) are the coordinates of the spatial point, and D is the directed distance from the origin to the plane.
9. The five-axis machine tool line laser in-situ measurement and hole position adaptive alignment system according to claim 8, characterized in that, The identification of the current hole diameter in module M3 includes: extracting planar point clouds at a distance greater than 1.1 times the theoretical radius from the hole center projection, fitting the plane equation Ax+By+Cz+D=0, extracting conical hole point clouds at a distance less than 0.9 times the theoretical radius from the hole center projection, dividing the conical hole point clouds into left and right groups according to the relative position of the center of the circle, fitting the spatial straight line equations for each group, finding the intersection of the spatial straight line and the plane as the edge points of the conical hole, fitting the edge points into a spatial circle, and the diameter of the circle is the current hole diameter d1.
10. The five-axis machine tool line laser in-situ measurement and hole position adaptive alignment system according to claim 9, characterized in that, The calculated depth compensation in module M3 includes: based on the current notch diameter d1 and the final notch diameter d2 set by the program, the given tool angle. The depth compensation amount Δd is calculated using the following expression: Where θ is the pit angle.
Citation Information
Patent Citations
Hole site precision measuring jig, manufacturing method and detection and correction compensation method
CN117906496A
Apparatus and method for controlling the depth of a hang-on fastener hole counterbore
CN119457189B
Automatic compensation machining method for position degree of axial hole
CN113899329A
Counter sinking parameter detection method and system
CN116659404A
Dimple depth control method and device, storage medium and electronic equipment
CN117862574A