Analytical modeling method for model measuring point three-dimensional coordinates and Euler angles

Abstract

The utility model provides a kind of analytical modeling method of model measuring point three-dimensional coordinates and Euler angle, the utility model is suspended under crossbeam by crane by scanning workpiece, solve the deformation problem of large thin-walled part different from its working posture due to the workpiece to be scanned by gravity, scanner is installed at the end of manipulator, realize all-around scanning to workpiece, according to the distance signal of scanner to control the scanning distance between scanner and workpiece to be scanned, solve the fatigue of operator long time handheld scanner, while can stably keep scanner and workpiece to be scanned directly optimal scanning distance, the utility model can satisfy the automatic scanning of different size sheet metal parts in whole vehicle reverse engineering, solve the deformation problem of large sheet metal part different from its working posture due to gravity when being placed on traditional scanning platform, while three-dimensional coordinates and Euler angle of measuring point in whole vehicle crash test and body-in-white modal test can be obtained quickly, improve scanning efficiency, shorten reverse engineering cycle etc.

Description

Technical Field

[0001] This invention relates to the field of reverse engineering of complete vehicles, specifically to an analytical modeling method for the three-dimensional coordinates and Euler angles of model measurement points. Background Technology

[0002] Currently, with the continuous development of reverse engineering technology, reverse engineering has become a link between various advanced technologies in the new product development process. It is widely used in the modification and innovative design of industries such as automobiles, aircraft, and molds, and is one of the important technical means to achieve rapid development of new products.

[0003] Currently, most vehicle reverse engineering applications rely on manual handheld scanners. This method struggles to maintain optimal scanning distances for extended periods, is highly susceptible to subjective factors, and has a low level of automation. Furthermore, due to the significant dimensional differences between sheet metal and plastic parts, large sheet metal and plastic components, such as front bumpers, roofs, and rear bumpers, can deform under gravity when placed flat on the scanning platform, resulting in a significant discrepancy between the scanned workpiece's 3D point cloud data and its actual dimensions.

[0004] For automotive crash tests, it is necessary to measure the three-dimensional coordinates of the deformed parts of the vehicle body before and after the test. For modal tests, it is necessary to construct the geometric model of the body-in-white and measure the Euler angles of the acceleration sensors. Currently, the measurement of the three-dimensional coordinates of the measuring points in these two types of tests is mainly divided into two methods: coordinate measuring machine and manual measurement with measuring tools. However, neither of these methods can simultaneously meet the requirements of high measurement accuracy, high efficiency, and non-contact measurement. Furthermore, neither method can obtain the Euler angles of the sensors on the body-in-white in modal tests. Therefore, it is particularly important to provide an analytical modeling method for the three-dimensional coordinates and Euler angles of the model measuring points. Summary of the Invention

[0005] To overcome the shortcomings of the prior art, this invention provides an analytical modeling method for the three-dimensional coordinates and Euler angles of model measurement points. This invention uses a robotic arm to move along the slide rail around the workpiece to be scanned. With the six degrees of freedom of the robotic arm, it realizes omnidirectional and blind-angle automated scanning of the workpiece to be scanned. This solves the fatigue caused by the operator holding the scanner for a long time. At the same time, it can stably maintain the optimal scanning distance between the scanner and the workpiece to be scanned. It solves the problem that the existing technology cannot simultaneously achieve the requirements of high measurement accuracy, high efficiency and non-contact operation.

[0006] To achieve the aforementioned inventive objectives, the present invention employs the following technical solution:

[0007] An analytical modeling method for the three-dimensional coordinates and Euler angles of model measurement points, the analytical modeling method specifically includes the following steps:

[0008] The first step is to measure the body-in-white using a scanning device. The specific measurement steps are as follows:

[0009] A. Place the white car body to be scanned under the crossbeam in the scanning device;

[0010] B. Determine the position of the suspension point of the body-in-white, and adjust the position of the two crossbeams in the scanning device and the crane so that the crane is located above the suspension point of the body-in-white.

[0011] C. Start the crane, lower the steel wire rope in the crane to the white body, and fix the steel wire rope to the white body;

[0012] D. Start the crane to lift the body-in-white to the predetermined position and observe whether the spatial position of the body-in-white meets the design requirements. If it meets the design requirements, proceed to the next step. If it does not meet the design requirements, adjust the body-in-white using the lifting crane.

[0013] E. Adjust the position of the 3D camera in the scanning device and observe whether the position of the 3D camera meets the design requirements. If it meets the design requirements, proceed to the next step. If it does not meet the design requirements, adjust the spatial position and shooting angle of the 3D camera until it meets the design requirements.

[0014] F. Start the 3D camera. First, calibrate the 3D camera and capture the outline of the outer surface of the white body. Then, plan the first scanning path of the scanner by adjusting the computer in the scanning device.

[0015] G. Start the scanner and use the distance signal sensor on the scanner to determine whether the scanning distance meets the design requirements. If it does, proceed to the next step. If it does not meet the design requirements, adjust the robot arm to position it at the preset scanning position.

[0016] H. Start the robotic arm and make it perform motion scanning along the initial scanning path planned by the computer;

[0017] 1. After the robotic arm completes the scan along the initial scanning path, observe whether the model's integrity meets the design requirements. If it does, proceed to the next step. If it does not meet the design requirements, replan the scanning path using the computer and scan again until the model meets the requirements.

[0018] J. Select a point in the scanned 3D point cloud data as the center coordinate (0, 0, 0) and the positive directions of the X, Y, and Z axes. The coordinates of other points are also determined accordingly. Select the coordinates of the points constituting the geometric model required in the white body experiment to obtain the geometric model of the white body in the experiment. At the same time, fit the triangular facets around the constituting points of the geometric model to a plane the size of the three-dimensional accelerometer used in the experiment. The angle between the fitted plane and the three coordinate axes is calculated, which is the Euler angle required in the experiment.

[0019] The second step involves analytically modeling the 3D coordinates and Euler angles of the model's measurement points, specifically including the following steps:

[0020] A. Import the geometric model into the computer analysis software and analyze the model;

[0021] B. Define the origin of the model and the positive X, Y, and Z directions; the coordinates of other points are then determined accordingly.

[0022] C. Determine the location of the measurement points for the body-in-white modal test, and select the required measurement points in the model;

[0023] D. Fit the surface patch around the selected measurement point to a plane the size of the three-dimensional accelerometer, and define the X, Y, and Z directions of the plane according to the sensor orientation in the body-in-white modal test;

[0024] E. The angle between the global coordinate system of the automatically calculated model and the local coordinate system of the plane is the Euler angle required in the modal test;

[0025] F. Automatically generate a modal test model based on the coordinates and Euler angles of the measuring points;

[0026] G. Import the established modal test model into the modal analysis software in the computer and conduct modal tests directly.

[0027] The analytical modeling method for the three-dimensional coordinates and Euler angles of the model measurement points, specifically includes the following steps in the first step of collecting the outer surface contour of the white body:

[0028] A. Start the 3D camera and take a full-view photo of the white body;

[0029] B. Stitch together the acquired 3D images to obtain the outer surface outline of the white body;

[0030] C. The computer plans the initial scanning path based on the collected outer surface contour of the white body;

[0031] The analytical modeling method for the three-dimensional coordinates and Euler angles of the model measurement points, in the first step of scanning the white body using a scanner, specifically includes the following steps:

[0032] A. Start the robotic arm and scanner to perform the first scan along the planned scanning path;

[0033] B. After the scan is completed, the computer determines whether there are any markers outside the model. If there are no markers, the model is complete and the scan ends. Otherwise, the markers outside the model are collected, and the computer plans the scan path again based on the collected markers outside the model until the model is complete.

[0034] The analytical modeling method for the three-dimensional coordinates and Euler angles of the model measurement points, in the first step, includes a scanning device comprising a 3D camera, a crossbeam, a crane, a robot arm, a scanner, a slide table, a computer, and a truss. Two sliding crossbeams are mounted on the truss, and at least two sliding cranes are mounted on each crossbeam. The end of the steel cable of each crane is connected to the workpiece to be scanned. 3D cameras that slide vertically are mounted on the sides of the four columns of the truss. The 3D cameras are connected to the computer via 3D camera data transmission lines. A U-shaped slide table is located at the bottom of the truss, and a slide table guide rail is mounted on the slide table. The slide table guide rail is connected to a robot arm base, and a robot arm is mounted on the robot arm base. The robot arm is connected to the scanner, which is connected to the computer via a scanner data transmission line. The robot arm is connected to a robot arm controller.

[0035] The analytical modeling method for the three-dimensional coordinates and Euler angles of the model measuring points is described above. The truss is provided with two longitudinal guide rails at intervals, and the two longitudinal guide rails are respectively connected to the two ends of the crossbeam.

[0036] The analytical modeling method for the three-dimensional coordinates and Euler angles of the model measurement points is described above. The crossbeam is equipped with a transverse guide rail, and a crane is installed on each of the transverse guide rails.

[0037] The analytical modeling method for the three-dimensional coordinates and Euler angles of the model measurement points is described above. The four columns of the truss are provided with vertical guide rails on their sides, and a 3D camera base is provided on each vertical guide rail. A 3D camera is provided on each 3D camera base.

[0038] The analytical modeling method for the three-dimensional coordinates and Euler angles of the model measurement points, wherein the robotic arm includes a rotating arm, a robotic arm upper arm, a robotic arm lower arm, a robotic wrist, and a connecting rod, wherein the rotating arm is mounted on the base of the robotic arm, and the rotating arm is connected to the lower end of the robotic arm upper arm and the connecting rod respectively, the upper end of the robotic arm upper arm and the connecting rod are connected to the left end of the robotic arm lower arm respectively, the right end of the robotic arm lower arm is connected to the robotic wrist, and the robotic wrist is connected to a scanner.

[0039] The analytical modeling method for the three-dimensional coordinates and Euler angles of the model measurement points, wherein the crane includes a motor, a motor bracket, a wire rope, a drum, a platform, a guide wheel, a guide wheel bracket, and a platform slider. The platform slider is connected to a transverse guide rail mounted on a crossbeam. A platform is mounted above the platform slider. Two motor brackets are spaced apart on the platform. A drum is mounted between the two motor brackets. One end of the drum is connected to the motor. A wire rope is wound around the outer edge of the drum. A guide wheel bracket is mounted above the platform below the drum. Two guide wheels are mounted on the guide wheel bracket. The end of the wire rope is lifted and lowered via the guide wheels.

[0040] The analytical modeling method for the three-dimensional coordinates and Euler angles of the model measurement points is described above, and the lower ends of the four columns of the truss are respectively provided with truss bases.

[0041] By employing the technical solution described above, the present invention has the following advantages:

[0042] This invention solves the problem of deformation of large, thin-walled parts due to gravity, which differs from their working posture, by suspending the workpiece under a beam using a crane. The scanner is mounted at the end of a robotic arm, which drives the scanner to achieve omnidirectional scanning of the workpiece. The scanning distance between the scanner and the workpiece is controlled based on the scanner's distance signal, eliminating operator fatigue caused by prolonged scanner handling. It also maintains a stable and optimal scanning distance between the scanner and the workpiece. This invention can automate the scanning of sheet metal parts of different sizes in reverse engineering of complete vehicles, solving the problem of large sheet metal parts deforming due to gravity when placed flat on a traditional scanning platform. Furthermore, it can quickly obtain the three-dimensional coordinates and Euler angles of measurement points in vehicle crash tests and body-in-white modal tests, improving scanning efficiency and shortening the reverse engineering cycle. It is suitable for widespread promotion and application. Attached Figure Description

[0043] Figure 1 This is a schematic diagram of the scanning device scanning a white body in an embodiment of the present invention;

[0044] Figure 2 This is a schematic diagram of the scanning device scanning the front bumper of a car in an embodiment of the present invention;

[0045] Figure 3 This is a simplified structural diagram of the scanning device in an embodiment of the present invention;

[0046] Figure 4 This is a schematic diagram of the robotic arm in the scanning device according to an embodiment of the present invention;

[0047] Figure 5 This is a schematic diagram of the crane structure in the scanning device according to an embodiment of the present invention;

[0048] Figure 6 This is a flowchart illustrating the operation of the scanning device in an embodiment of the present invention.

[0049] Figure 7 This is a flowchart of the scanning device in an embodiment of the present invention;

[0050] Figure 8 This is a flowchart of the analytical modeling method in an embodiment of the present invention;

[0051] In the diagram: 1. Body-in-white; 2. 3D camera; 3. 3D camera base; 4. Crossbeam; 5. Crane; 5-1. Motor; 5-2. Motor bracket; 5-3. Wire rope; 5-4. Drum; 5-5. Platform; 5-6. Guide wheel; 5-7. Guide wheel bracket; 5-8. Platform slider; 6. Robotic arm base; 6-1. Robotic arm controller; 7. Robotic arm; 7-1. Rotating arm; 7-2. Robotic arm upper arm; 7-3. Robotic arm forearm; 7-4. Robotic wrist; 7-5. Link; 8. Scanner; 9. Longitudinal guide rail; 10. Transverse guide rail; 11. Vertical guide rail; 12. Slide table; 13. Slide table guide rail; 14. Truss base; 15. Car front bumper; 16. Computer; 17. Scanner data transmission cable; 18. 3D camera data transmission cable; 19. Truss. Detailed Implementation

[0052] The present invention can be explained in more detail through the following embodiments, but the present invention is not limited to the following embodiments;

[0053] In the description of this invention, it should be understood that the terms "center," "side," "length," "width," "height," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and "side," etc., indicate the orientation or positional relationship based on the appendix. Figure 1 The orientations or positional relationships shown are for the convenience of describing the present invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting the present invention.

[0054] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0055] Combined with appendix Figures 1-8 The present invention discloses an analytical modeling method for the three-dimensional coordinates and Euler angles of a model measurement point, the analytical modeling method specifically including the following steps:

[0056] Step 1: Measure the body-in-white 1 using a scanning device, combined with... Figure 1 and Figure 6 The specific measurement steps are as follows:

[0057] A. Place the white body 1 to be scanned under the crossbeam 4 in the scanning device; In practice, the white body 1 to be scanned can be replaced with other workpieces to be scanned, such as the front bumper 15 of a car. That is to say, the workpieces to be scanned can be divided into sheet metal parts or plastic parts or the whole vehicle of different sizes and specifications and have photosensitive patches attached to the surface.

[0058] B. Determine the position of the suspension point of the body-in-white 1, and adjust the position of the two crossbeams 4 and the crane 5 in the scanning device so that the crane 5 is located above the suspension point of the body-in-white 1.

[0059] C. Start the crane 5, lower the steel wire rope 5-3 in the crane 5 to the body-in-white 1, and fix the steel wire rope 5-3 to the body-in-white 1.

[0060] D. Start the crane 5 and lift the body-in-white 1 to the predetermined position. Observe whether the spatial position of the body-in-white 1 meets the design requirements. If it meets the design requirements, proceed to the next step. If it does not meet the design requirements, adjust the body-in-white 1 using the lifting crane 5.

[0061] E. Adjust the position of 3D camera 2 in the scanning device and observe whether the position of 3D camera 2 meets the design requirements. If it meets the design requirements, proceed to the next step. If it does not meet the design requirements, adjust the spatial position and shooting angle of 3D camera 2 until it meets the design requirements.

[0062] F. Start the 3D camera 2, first calibrate the 3D camera 2, collect the outer surface contour of the white body 1, and then plan the first scanning path of the scanner 8 by adjusting the computer 16 in the scanning device.

[0063] G. Start the scanner 8. Use the distance signal sensor on the scanner 8 to determine whether the scanning distance of the scanner 8 meets the design requirements. If it meets the design requirements, proceed to the next step. If it does not meet the design requirements, adjust the robot arm 7 to be located at the preset scanning position.

[0064] H. Start the robotic arm 7 and make it perform motion scanning along the initial scanning path planned by the computer 16;

[0065] 1. After the robotic arm 7 completes the scan along the initial scan path, it observes whether the model's integrity meets the design requirements. If it does, proceed to the next step. If it does not meet the design requirements, the computer 16 replans the scan path and performs a second scan until the model meets the requirements.

[0066] J. Select a point in the scanned 3D point cloud data as the center coordinate (0, 0, 0) and the positive direction of the X, Y, and Z axes. The coordinates of other points are also determined accordingly. Select the coordinates of the points constituting the geometric model required in the experiment of body-in-white 1 to obtain the geometric model of body-in-white 1 in the experiment. At the same time, fit the triangular facets around the constituting points of the geometric model to a plane the size of the three-dimensional accelerometer used in the experiment. The angle between the fitted plane and the three coordinate axes is calculated, which is the Euler angle required in the experiment.

[0067] The second step is to perform analytical modeling of the three-dimensional coordinates and Euler angles of the model's measurement points, combined with the attached... Figure 1 and appendix Figure 8 Specifically, it includes the following steps:

[0068] A. Import the geometric model into the analysis software in computer 16 and analyze the model;

[0069] B. Define the origin of the model and the positive X, Y, and Z directions; the coordinates of other points are then determined accordingly.

[0070] C. Determine the location of the test points for the modal test of the body-in-white, and select the required test points in the model;

[0071] D. Fit the surface patch around the selected measurement point to a plane the size of the three-dimensional accelerometer, and define the X, Y, and Z directions of the plane according to the sensor orientation in the modal test of the body-in-white.

[0072] E. The angle between the global coordinate system of the automatically calculated model and the local coordinate system of the plane is the Euler angle required in the modal test;

[0073] F. Automatically generate a modal test model based on the coordinates and Euler angles of the measuring points;

[0074] G. Import the established modal test model into the modal analysis software on computer 16 and conduct modal tests directly.

[0075] In specific implementation, in conjunction with the appendix Figure 7 The first step of collecting the outer surface contour of the white body 1 specifically includes the following steps:

[0076] A. Start 3D camera 2 to take a full-view photo of the white body 1;

[0077] B. Stitch together the collected 3D images to obtain the outer surface contour of the white body 1;

[0078] C. The computer 16 plans the initial scanning path based on the collected outer surface contour of the white body 1;

[0079] Furthermore, in conjunction with the appendix Figure 7The first step of scanning the white body 1 using scanner 8 specifically includes the following steps:

[0080] A. Start the robotic arm 7 and scanner 8 to perform the first scan along the planned scanning path;

[0081] B. After the scan is completed, the computer 16 determines whether there are any marker points outside the model. If there are no marker points, the model is complete and the scan ends. Otherwise, the computer 16 collects the marker points outside the model and replans the scan path based on the collected marker points outside the model until the model is complete.

[0082] In practice, the computer 16 shown is equipped with an analysis system. Since the analysis system and modal analysis software are commonly used in the field and are not the focus of protection of this invention, they will not be described in detail here.

[0083] Furthermore, such as Figure 1 , 3As shown, the scanning device in the first step includes a 3D camera 2, a crossbeam 4, a crane 5, a robotic arm 7, a scanner 8, a sliding table 12, a computer 16, and a truss 19. Two crossbeams 4 that slide back and forth are located on the truss 19. At least two cranes 5 that slide left and right are located on each crossbeam 4. The ends of the steel wire ropes 5-3 of each crane 5 are connected to the workpiece to be scanned. 3D cameras 2 that slide up and down are located on the sides of the four columns of the truss 19. The 3D cameras 2 are connected to the computer 16 via 3D camera data transmission lines 18. A U-shaped sliding table 12 is located at the bottom of the truss 19. A sliding table guide rail 13 is located on the top of the sliding table 12. The sliding table guide rail 13 is connected to a robotic arm base 6. A robotic arm 7 is located on the robotic arm base 6. In practice, the robotic arm 7 has a multi-axis linkage structure, enabling it to operate in space. The robot arm 7 performs translational motion along the X, Y, and Z axes and rotational motion around the X, Y, and Z axes. The robot arm 7 is mounted on a robot arm base 6, which is equipped with a drive device to enable the robot arm 7 to move along the slide rail 13. A robot arm controller 6-1 is mounted on the robot arm base 6 to send motion control signals to the robot arm 7. The robot arm 7 is connected to a scanner 8. During implementation, the scanner 8 is connected to the end of the robot arm 7. The laser beam emitted by the scanner 8 hits the surface of the workpiece being scanned, and the robot arm receives the reflected beam from the photosensitive patch on the surface of the workpiece to obtain the contour information of the workpiece. The computer 16 displays the triangular facet model of the scanned workpiece in real time and can plan the scanning path based on the photosensitive patch outside the model acquired by the scan. The scanner 8 is connected to the computer 16 via a scanner data transmission line 17, and the robot arm 7 is connected to the robot arm controller 6-1. During implementation, the robot controller 6-1 determines the distance between itself and the workpiece being measured by scanning the real-time image, preventing the robot 7 from colliding with the workpiece; the scanner 8 is equipped with a distance signal sensor, and the distance signal is the motion control signal of the robot 7, which can always keep the scanner 8 and the workpiece being scanned at the optimal scanning distance.

[0084] Furthermore, such as Figure 1 As shown, the truss 19 has two longitudinal guide rails 9 spaced apart on its upper part, and the two longitudinal guide rails 9 are respectively connected to the two ends of the crossbeam 4.

[0085] Furthermore, such as Figure 1 As shown, the crossbeam 4 is provided with a transverse guide rail 10, and a crane 5 is provided on the transverse guide rail 10.

[0086] Furthermore, such as Figure 1 As shown, the four columns of the truss 19 are provided with vertical guide rails 11 on their sides, and a 3D camera base 3 is provided on each vertical guide rail 11, and a 3D camera 2 is provided on each 3D camera base 3.

[0087] Furthermore, such as Figure 4As shown, the robotic arm 7 includes a rotating arm 7-1, a robotic upper arm 7-2, a robotic forearm 7-3, a robotic wrist 7-4, and a connecting rod 7-5. The rotating arm 7-1 is mounted on the robotic arm base 6. The rotating arm 7-1 is connected to the lower ends of the robotic upper arm 7-2 and the connecting rod 7-5. The upper ends of the robotic upper arm 7-2 and the connecting rod 7-5 are connected to the left ends of the robotic forearm 7-3. The right end of the robotic forearm 7-3 is connected to the robotic wrist 7-4. The robotic wrist 7-4 is connected to the scanner 8.

[0088] Furthermore, such as Figure 5 As shown, the crane 5 includes a motor 5-1, a motor bracket 5-2, a wire rope 5-3, a drum 5-4, a platform 5-5, guide wheels 5-6, a guide wheel bracket 5-7, and a platform slider 5-8. The platform slider 5-8 is connected to a transverse guide rail 10 mounted on a crossbeam 4. The platform 5-5 is mounted on top of the platform slider 5-8. Two motor brackets 5-2 are spaced apart on the platform 5-5. The drum 5-4 is positioned between the two motor brackets 5-2. One end of the drum 5-4 is connected to the motor 5-1. The wire rope 5-3 is wound around the outer edge of the drum 5-4. The guide wheel bracket 5-7 is located on top of the platform 5-5 below the drum 5-4. Two guide wheels 5-6 are mounted on the guide wheel bracket 5-7. The end of the wire rope 5-3 is lifted and lowered via the guide wheels 5-6.

[0089] Furthermore, such as Figure 1 As shown, the lower ends of the four columns of the truss 19 are respectively provided with truss bases 14.

[0090] Furthermore, such as Figure 2 As shown, the workpiece to be scanned can be a white car body 1, or it can be a car front bumper 15.

[0091] In specific implementations of this invention, such as Figures 1-3 As shown, the truss base 14 is fixedly installed on the ground. The truss 19 consists of four columns and two horizontal plates. Longitudinal guide rails 9 are provided on the two horizontal plates, and the two longitudinal guide rails 9 are respectively connected to the crossbeams 4. Transverse guide rails 10 are provided on the crossbeams 4. Vertical guide rails 11 are provided on the four columns of the truss 4. Four cranes 5 are arranged on the transverse guide rails 10. The white body 1 or the front bumper 15 of the car is suspended at the end of the steel wire rope 5-3 in the crane 5. The suspension posture of the scanning workpiece is realized by controlling the lifting and lowering of the four cranes 5. The cranes 5 are driven by the slide table and guide rail or by the gear rack and servo motor to realize the translation of the cranes 5 on the crossbeams 4 in the X and Y directions. The spacing of the cranes 5 is changed to realize the scanning of body sheet metal parts, white body 1 or whole vehicle of different sizes and specifications.

[0092] Furthermore, the equipment mounted on the horizontal guide rail 10, the vertical guide rail 9, and the vertical guide rail 11 can all be driven by the guide rail and slide table or by the gear rack and servo motor. In implementation, the horizontal guide rail 10, the vertical guide rail 9, and the vertical guide rail 11 can be standard parts, such as electric slide tables.

[0093] The 3D camera 2 is mounted on the vertical guide rail 11 on the truss 19, and its height can be adjusted by a drive. Simultaneously, the 3D camera 2 is connected to the 3D camera base 3 via a ball joint, allowing it to be adjusted vertically and rotated on the 3D camera base 3 to increase the shooting angle. After the workpiece is adjusted to a suitable position, the 3D camera 2 simultaneously starts capturing images of the scanned workpiece, acquiring the outer surface contour of the workpiece. The captured 3D image data is transmitted to the computer 16 via the 3D camera data transmission line 18, and the initial scanning path of the scanner 8 is planned accordingly.

[0094] like Figure 4 As shown, the robotic arm 7 has a multi-axis linkage structure, capable of translational motion along the X, Y, and Z axes and rotation around the X, Y, and Z axes in space. The slide rail 13 is fixed to the ground, and the robotic arm base 6 is equipped with a drive device, enabling the robotic arm 7 to move along the slide rail 13 around the scanned workpiece, achieving omnidirectional scanning of the workpiece. A robotic arm controller 6-1 is installed on the robotic arm base 6. After the scanner 8 completes scanning within the optimal scanning distance, the robotic arm controller 6-1 sends motion signals to the robotic arm 7 according to the scanning path planned by the computer 16 to control the movement of the robotic arm 7 on the slide rail 13. The scanner 8 is connected to the end of the robotic arm 7. The laser beam emitted by the scanner 8 hits the surface of the scanned workpiece, and the reflected beam from the photosensitive patch on the surface of the scanned workpiece is received by triangulation to obtain the contour information of the scanned workpiece. The computer 16 displays the triangular facet model of the scanned workpiece in real time, and at the same time, the computer 16 replans the scanning path based on the photosensitive patch outside the model collected during the scanning process. Scanner 8 is connected to computer 16 via scanner data transmission cable 17. Computer 16 calculates the distance between robot arm 7 and the workpiece based on the real-time scanned image, preventing robot arm 7 from colliding with the workpiece during operation. Scanner 8 is equipped with a distance signal sensor, which collects the distance information between the end of scanner 7 and the workpiece and sends the signal to robot arm controller 6-1 via scanner data transmission cable 17. Robot arm controller 6-1 uses this signal to control the six degrees of freedom movement of robot arm 7, ensuring that scanner 8 maintains the optimal scanning distance between the scanner and the workpiece at all times. This solves the problems of poor scanning distance control, excessive or insufficient scanning distance, that occur during manual scanning, improving scanning efficiency and image quality.

[0095] Furthermore, such as Figure 5As shown, the crane 5 is mounted on the transverse guide rail 10 on the crossbeam 4. The crane 5 consists of a motor 5-1, a motor bracket 5-2, a wire rope 5-3, a drum 5-4, a platform 5-5, a guide wheel 5-6, a guide wheel bracket 5-7, and a platform slider 5-8. The crane 5 is driven by the motor 5-1, which is supported by the motor bracket 5-2. The motor bracket 5-2 is fixed to the platform 5-5. The drum 5-4 has a spiral rope groove to ensure that the wire rope is neatly arranged and not tangled. The wire rope 5-3 passes through the guide wheel 5-6 and the platform slider 5-8 to connect with the scanned workpiece. The guide wheel 5-6 is supported by the guide wheel bracket 5-7.

[0096] Furthermore, such as Figure 3 and Figure 6 As shown, the computer 16 used in conjunction with the scanner can receive the scanned workpiece contour information returned by the scanner 8 through the scanner data transmission line 17. After the software algorithm calculates the three-dimensional point cloud data of the scanned workpiece, a point is determined in the three-dimensional point cloud data as the center coordinate (0, 0, 0) and the positive direction of the X, Y, and Z axes. The three coordinates of other points are also determined accordingly. In the body-in-white modal test, it is only necessary to scan the three-dimensional point cloud data of the body-in-white and select the three-dimensional coordinates of the geometric model constituent points required in the experiment to easily obtain the geometric model of the body-in-white in the experiment. At the same time, the triangular facets around the constituent points of the geometric model are fitted into a plane the size of the three-dimensional accelerometer used in the experiment. In this way, the angle between the fitted plane and the three coordinate axes can be easily obtained by calculation, which is the Euler angle required in the experiment.

[0097] The advantages of this invention are as follows:

[0098] 1. This invention utilizes the coordinated use of the truss 19, crossbeam 4, crane 5, robotic arm 7, and computer 16. The robotic arm 7 moves along the slide rail 13 around the scanned workpiece, achieving omnidirectional, blind-spot-free automated scanning of the workpiece through its six degrees of freedom. The scanning distance between the scanner 8 and the workpiece is controlled based on the distance signal from the scanner 8. This solves the operator fatigue caused by prolonged scanner handling and maintains a stable, optimal scanning distance between the scanner and the workpiece. The crane 5 can suspend large sheet metal and plastic parts under the horizontal guide rail 10, resolving the issue of deformation of large, thin-walled parts due to gravity, which differs from their working posture. This addresses the problem of significant errors between the 3D point cloud data and the actual workpiece, resolving the inability of existing technologies to simultaneously achieve high measurement accuracy, high efficiency, and non-contact operation.

[0099] 2. This invention uses computer 16 to obtain the three-dimensional coordinates and Euler angles of the measuring points in various car tests. It scans the car body before and after the collision test, and calculates the change in the three-dimensional coordinates of the deformed parts by comparing the three-dimensional point cloud data of the car body before and after the test, and obtains the intrusion amount of each part of the car body. In the white body modal test, the three-dimensional point cloud data of the white body is obtained by scanning, and the three-dimensional coordinates of the geometric constituent points of the experimental model and the Euler angles of the sensor are obtained from it.

[0100] 3. This invention is versatile and can meet the scanning needs of workpieces of different sizes, materials and specifications. Compared with traditional scanning methods, it can save time and costs, increase scanning efficiency and shorten the reverse engineering cycle.

[0101] 4. This invention scans high-quality three-dimensional point cloud data of a workpiece in one go by suspending the workpiece, which solves the problem that existing detection methods cannot obtain complete three-dimensional point cloud data of a scanned workpiece in one go. It obtains the overall point cloud data of the workpiece by fitting the point cloud data from both the front and back sides.

[0102] The parts of this invention not described in detail are prior art.

[0103] The embodiments selected herein for the purpose of disclosing the inventive objectives are currently considered suitable; however, it should be understood that the invention is intended to include all variations and modifications of the embodiments that fall within the scope of this concept and invention.

Claims

1. An analytical modeling method for the three-dimensional coordinates and Euler angles of model measurement points, characterized by: The analytical modeling method specifically includes the following steps: Step 1: Measure the body-in-white (1) using a scanning device. The specific measurement steps are as follows: A. Place the white body to be tested (1) under the crossbeam (4) in the scanning device; B. Determine the position of the suspension point of the white body (1), and adjust the position of the two crossbeams (4) and the crane (5) in the scanning device so that the crane (5) is located above the suspension point of the white body (1); C. Start the crane (5), lower the wire rope (5-3) in the crane (5) to the white body (1), and fix the wire rope (5-3) to the white body (1); D. Start the crane (5) to lift the white body (1) to the predetermined position and observe whether the spatial position of the white body (1) meets the design requirements. If it meets the design requirements, proceed to the next step. If it does not meet the design requirements, adjust the white body (1) using the lifting crane (5). E. Adjust the position of the 3D camera (2) in the scanning device and observe whether the position of the 3D camera (2) meets the design requirements. If it meets the design requirements, proceed to the next step. If it does not meet the design requirements, adjust the spatial position and shooting angle of the 3D camera (2) until it meets the design requirements. F. Start the 3D camera (2), first calibrate the 3D camera (2), collect the outer surface contour of the white body (1), and then plan the first scanning path of the scanner (8) by adjusting the computer (16) in the scanning device; G. Start the scanner (8) and use the distance signal sensor on the scanner (8) to determine whether the scanning distance of the scanner (8) meets the design requirements. If it meets the design requirements, proceed to the next step. If it does not meet the design requirements, adjust the robot (7) to place it in the preset scanning position. H. Start the robotic arm (7) and make it perform motion scanning along the initial scanning path planned by the computer (16); I. After the robot arm (7) completes the scan along the first scan path, observe whether the integrity of the model meets the design requirements. If it meets the design requirements, proceed to the next step. If it does not meet the design requirements, use the computer (16) to plan the scan path again and perform a second scan until the model meets the requirements. J. Select a point as the center coordinate (0, 0, 0) in the scanned three-dimensional point cloud data and confirm the positive directions of the X, Y, and Z axes. The coordinates of other points are also determined. Select the coordinates of the points that constitute the geometric model required in the experiment of the white body (1) to obtain the geometric model of the white body (1) in the experiment. At the same time, fit the triangular facets around the points that constitute the geometric model into a plane the size of the three-dimensional accelerometer used in the experiment. The angle between the fitting plane and the three coordinate axes is calculated, which is the Euler angle required in the experiment. The second step involves analytically modeling the 3D coordinates and Euler angles of the model's measurement points, specifically including the following steps: A. Import the geometric model into the analysis software in the computer (16) and analyze the model; B. Define the origin of the model and the positive X, Y, and Z directions; the coordinates of other points are then determined accordingly. C. Determine the location of the test points for the modal test of the white body (1), and select the test points required for the test in the model; D. Fit the surface around the selected measurement point to a plane the size of the three-dimensional accelerometer, and specify the X, Y, and Z directions of the plane according to the sensor orientation in the modal test of the white body (1); E. The angle between the global coordinate system of the automatically calculated model and the local coordinate system of the plane is the Euler angle required in the modal test; F. Automatically generate a modal test model based on the coordinates and Euler angles of the measuring points; G. Import the established modal test model into the modal analysis software in the computer (16) and conduct modal tests directly.

2. The analytical modeling method for the three-dimensional coordinates and Euler angles of the model measurement points according to claim 1, characterized in that: The first step of collecting the outer surface contour of the white body (1) specifically includes the following steps: A. Start the 3D camera (2) and take a full-view photo of the white body (1); B. The collected 3D images are stitched together to obtain the outer surface contour of the white body (1); C. The computer (16) plans the first scanning path based on the outer surface contour of the white body (1) collected.

3. The analytical modeling method for the three-dimensional coordinates and Euler angles of the model measurement points according to claim 1, characterized in that: The first step of scanning the white body (1) using the scanner (8) specifically includes the following steps: A. Start the robotic arm (7) and scanner (8) to perform the first scan along the planned scanning path; B. After the scan is completed, the computer (16) determines whether there are any markers outside the model. If there are no markers, the model is complete and the scan ends. Otherwise, the markers outside the model are collected, and the computer (16) plans the scan path again based on the collected markers outside the model until the model is complete.

4. The analytical modeling method for the three-dimensional coordinates and Euler angles of the model measurement points according to claim 1, characterized in that: The scanning device in the first step includes a 3D camera (2), a crossbeam (4), a crane (5), a robot (7), a scanner (8), a slide table (12), a computer (16), and a truss (19). Two crossbeams (4) that slide back and forth are provided on the top of the truss (19). At least two cranes (5) that slide left and right are provided on each crossbeam (4). The end of the steel wire rope (5-3) of each crane (5) is connected to the workpiece to be scanned. 3D cameras (2) that slide up and down are provided on the sides of the four columns of the truss (19). The 3D camera (2) is connected to the computer (16) via the 3D camera data transmission line (18). A U-shaped slide (12) is provided at the bottom of the truss (19). A slide guide rail (13) is provided on the slide (12). The slide guide rail (13) is connected to the robot base (6). A robot (7) is provided on the robot base (6). The robot (7) is connected to the scanner (8). The scanner (8) is connected to the computer (16) via the scanner data transmission line (17). The robot (7) is connected to the robot controller (6-1).

5. The analytical modeling method for the three-dimensional coordinates and Euler angles of the model measurement points according to claim 4, characterized in that: The truss (19) is provided with two longitudinal guide rails (9) spaced apart on its upper part, and the two longitudinal guide rails (9) are respectively connected to the two ends of the crossbeam (4).

6. The analytical modeling method for the three-dimensional coordinates and Euler angles of the model measurement points according to claim 4, characterized in that: The crossbeam (4) is provided with a transverse guide rail (10), and a crane (5) is provided on the transverse guide rail (10).

7. The analytical modeling method for the three-dimensional coordinates and Euler angles of the model measurement points according to claim 4, characterized in that: The four columns of the truss (19) are provided with vertical guide rails (11) on their sides, and a 3D camera base (3) is provided on each vertical guide rail (11), and a 3D camera (2) is provided on each 3D camera base (3).

8. The analytical modeling method for the three-dimensional coordinates and Euler angles of the model measurement points according to claim 4, characterized in that: The robotic arm (7) includes a rotating arm (7-1), a robotic arm upper arm (7-2), a robotic arm lower arm (7-3), a robotic wrist (7-4), and a connecting rod (7-5). The rotating arm (7-1) is mounted on the robotic arm base (6). The rotating arm (7-1) is connected to the lower ends of the robotic arm upper arm (7-2) and the connecting rod (7-5). The upper ends of the robotic arm upper arm (7-2) and the connecting rod (7-5) are connected to the left end of the robotic arm lower arm (7-3). The right end of the robotic arm lower arm (7-3) is connected to the robotic wrist (7-4). The robotic wrist (7-4) is connected to the scanner (8).

9. The analytical modeling method for the three-dimensional coordinates and Euler angles of the model measurement points according to claim 4, characterized in that: The crane (5) includes a motor (5-1), a motor bracket (5-2), a wire rope (5-3), a drum (5-4), a platform (5-5), a guide wheel (5-6), a guide wheel bracket (5-7), and a platform slider (5-8). The platform slider (5-8) is connected to a transverse guide rail (10) mounted on a crossbeam (4). A platform (5-5) is mounted on top of the platform slider (5-8), and two motor brackets (5-6, 5-7, 5-8) are spaced apart on top of the platform (5-5). -2), a drum (5-4) is set between the two motor brackets (5-2). One end of the drum (5-4) is connected to the motor (5-1). A steel wire rope (5-3) is wound around the outer edge of the drum (5-4). A guide wheel bracket (5-7) is set on the platform (5-5) below the drum (5-4). Two guide wheels (5-6) are set on the guide wheel bracket (5-7). The end of the steel wire rope (5-3) is lifted up and down through the guide wheels (5-6).

10. The analytical modeling method for the three-dimensional coordinates and Euler angles of the model measurement points according to claim 4, characterized in that: The lower ends of the four columns of the truss (19) are respectively provided with truss bases (14).

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