A rotary 3D profilometry system

Abstract

This invention discloses a rotary 3D contour measurement system, belonging to the field of three-dimensional contour measurement technology. It includes a main body, on the inside of which a 3D measurement unit is installed. The 3D measurement unit includes a laser displacement sensor, a rotary drive mechanism, a control module, and a data processing module. The laser displacement sensor is used to measure the contour information of the object being measured in the X and Z directions. The rotary drive mechanism includes a rotary motor fixed to the inside of the main body. An angle encoder is installed on the rotating end of the rotary motor. The rotating end of the rotary motor is fixed to the center of a rotating platform. The laser displacement sensor is fixedly installed at the bottom of the rotating platform. The control module is connected to both the rotary drive mechanism and the laser displacement sensor. This rotary 3D contour measurement system is simple, has an adjustable scanning range, and the diameter of the detection circle changes with the measurement distance, adapting to measurement needs across different height ranges. It can simultaneously detect multiple weld features in a single measurement.

Description

Technical Field

[0001] This invention specifically relates to a rotary 3D contour measurement system, belonging to the field of three-dimensional contour measurement technology. Background Technology

[0002] Three-dimensional contour measurement technology has important applications in industrial inspection, quality control, reverse engineering, and other fields. Existing three-dimensional contour measurement methods, such as the one disclosed in Chinese Patent Publication No. CN117990003B (a method for synchronous scanning and measuring the three-dimensional contour of a lens module), effectively address the need for rapid and accurate measurement of the three-dimensional contour of a lens module. However, it cannot be applied to weld inspection, as it cannot simultaneously detect multiple weld features. Furthermore, existing 3D contour measurement methods mainly include the following technical solutions: Solution 1 combines a 2D contour meter with an external encoder. Using a 2D contour meter (measuring only the X and Z directions) in conjunction with an external encoder to achieve 3D measurement requires additional encoder equipment. The 2D contour meter needs to work with an external encoder to achieve 3D measurement, increasing system complexity and cost. Precise synchronization between the encoder and contour meter is required, making installation and debugging difficult, resulting in low system integration and disadvantages. Modular design; Scheme 2 uses an area array CMOS sensor for 3D contour measurement, which is costly and limits its application, thus restricting the widespread use of 3D contour measurement technology; Scheme 3 uses a traditional weld seam tracking system, which can only detect one weld seam feature (such as the weld seam center) at a time. For scenarios that require the detection of multiple features (center, edge, depth, width), multiple measurements are required, resulting in long measurement times, low efficiency, and impacting production efficiency; Scheme 4 uses a fixed rotating scanning system to form a circle with a fixed diameter that does not change with the measurement distance, making it unable to adapt to the measurement needs of different height ranges at different measurement distances, and unable to simultaneously meet the requirements of small circle diameter at close range and large circle diameter at long distance; In addition, existing 3D contour measurement systems are difficult to detect multiple weld seam features simultaneously in a single measurement, limiting their application in the welding field, especially in scenarios that require simultaneous detection of weld seam center, edge, depth, and width. Summary of the Invention

[0003] To address the aforementioned issues, this invention proposes a rotary 3D contour measurement system. The system is simple, low-cost, and has an adjustable scanning range. The diameter of the detection circle varies with the measurement distance, adapting to measurement needs across different height ranges. It can simultaneously detect multiple weld features in a single measurement.

[0004] The rotary 3D contour measurement system of the present invention includes a body, wherein a 3D measurement unit is installed inside the body, and the 3D measurement unit includes:

[0005] A laser displacement sensor is used to measure the contour information of a measured object in the X and Z directions. The laser displacement sensor incorporates an adjustable-angle reflector, which forms an angle α of 5° to 20° with the centerline of the laser displacement sensor. After angle adjustment, the reflector is fixed. The adjustable-angle reflector includes an angle-adjusting base on which the reflector is fixed. The reflective surface of the reflector is positioned on the light output path of the laser emitter. The angle-adjusting base has one pin hole and two angle-adjusting arc-shaped holes. The pin hole is connected to the laser displacement sensor via a pin shaft. The sensor's internal base is hinged, and a locking bolt is installed in the angle-adjusting arc-shaped hole. The locking bolt is screwed and secured to the base. When the laser displacement sensor is adjusted, the locking bolt is loosened, and the angle-adjusting seat is pushed. At this time, the angle-adjusting seat rotates along the pin shaft, and the angle-adjusting arc-shaped hole of the angle-adjusting seat swings in an arc along the locking bolt. When one end of the angle-adjusting arc-shaped hole swings and engages with the locking bolt, the adjustable angle reflector forms a 5° angle with the axis of the laser displacement sensor; when the other end of the angle-adjusting arc-shaped hole swings and engages with the locking bolt, the adjustable angle reflector forms a 20° angle with the axis of the laser displacement sensor. After the swinging seat completes its rotation and swing... The angle adjustment seat is locked to the base using locking bolts, thus completing the angle adjustment. When the entire laser displacement sensor rotates around its axis, the adjustable angle reflector forms an angle α with the axis, creating a circular scanning circle. The diameter of this circle varies with the measurement distance: the closer the distance, the smaller the circle; the farther the distance, the larger the circle. The effective measurement range is 350±250mm (100mm-600mm), with a near-end circle diameter of 35mm and a far-end circle diameter of 100mm. The laser displacement sensor uses a linear CMOS sensor with 1024-4096 pixels and a measurement frequency of 30Hz. The frequency range is 00-10000Hz (preferred value: 5000Hz) to meet the requirements of high-speed rotation measurement. Specifically, when the laser displacement sensor is working, the laser emitter emits a modulated beam. The beam is reflected by an adjustable-angle reflector to form a point laser spot. The reflected beam enters the object being measured. When the entire sensor rotates around the sensor axis, due to the angle α between the adjustable-angle reflector and the axis, the trajectory of the point laser in space forms a rotating scanning circle. Then, the laser beam reflected back from the object being measured (diffuse reflection) enters the sensor's imaging module (linear CMOS sensor) to achieve reflected light collection and imaging.

[0006] A rotary drive mechanism includes a rotary motor fixed to the inside of the machine body; an angle encoder is mounted on the rotating end of the rotary motor; the rotating end of the rotary motor is fixed to the center of the rotary platform; a laser displacement sensor is fixedly mounted on the bottom of the rotary platform; when the rotary drive mechanism drives the laser displacement sensor to rotate, due to the angle between the adjustable angle reflector and the vertical axis, the trajectory of the laser line in space forms a circle, and the diameter of the circle varies with the measurement distance; the rotary motor drives the rotary platform to rotate at a speed ranging from 100 to 3000 rpm; the laser displacement sensor is fixedly mounted on the rotary platform and rotates with the rotary platform; the angle encoder is used to detect the rotation angle in real time, with an angle detection accuracy of 0.01°-0.1°; it is used to detect the rotation angle in real time and feed the angle information back to the control module;

[0007] The control module calculates the three-dimensional coordinates of the surface of the object under test through coordinate transformation based on the rotation angle and the measurement data of the laser displacement sensor. The control module is connected to the rotation drive mechanism and the laser displacement sensor respectively. The control module is used to control the rotation speed of the rotary motor and the measurement parameters of the laser displacement sensor, and to receive the measurement data of the laser displacement sensor and the angle information of the angle encoder.

[0008] The data processing module, which is electrically connected to the control module, is used to calculate the three-dimensional contour information of the surface of the object being measured through coordinate transformation based on the measurement data of the rotation angle and the laser displacement sensor. The data processing module calculates the three-dimensional contour information (X, Y, Z coordinates) of the surface of the object being measured through coordinate transformation based on the measurement data of the rotation angle and the laser displacement sensor, with a measurement accuracy of ±0.01-0.05mm.

[0009] The laser displacement sensor rotates with the rotating platform to perform a 360° scan of the object under test. During the rotation, due to the angle α between the adjustable angle reflector and the vertical axis, the trajectory of the laser line in space forms a circle, the diameter of which varies with the measurement distance (35mm at the near end and 100mm at the far end). The laser displacement sensor continuously measures the contour information in the X and Z directions, the angle encoder detects the rotation angle θ in real time, and the data processing module calculates the Y coordinate through coordinate transformation, finally synthesizing a three-dimensional contour point cloud. Through 360° rotation scanning, complete three-dimensional contour information of the surface of the object under test can be obtained, and multiple weld features can be detected simultaneously in one measurement.

[0010] Furthermore, the control module acquires the rotation angle collected by the angle encoder and the measurement data from the laser displacement sensor, and calculates the three-dimensional coordinates of the surface of the object under test through coordinate transformation. Specifically, the X and Z coordinates are measured by the laser displacement sensor: X coordinate: directly measured by the laser displacement sensor, representing the displacement along the laser line direction, with a measurement accuracy of ±0.01-0.05mm; Z coordinate: directly measured by the laser displacement sensor, representing the displacement (height) perpendicular to the laser line, with a measurement accuracy of ±0.01-0.05mm; Y coordinate: calculated based on the rotation angle θ and the scanning radius R, Y=R×sin(θ), representing the position in the rotation direction, with measurement accuracy depending on the accuracy of the angle encoder, where θ is the rotation angle and R is the scanning radius.

[0011] Furthermore, the data processing module is an FPGA, which performs real-time data processing with a processing delay of less than 10ms.

[0012] Furthermore, a protective cover is fixed to the front end of the machine body via a flange, and a protective lens is fixed to the inside of the protective cover.

[0013] Furthermore, the machine body includes a detection cavity and a control cavity fastened by bolts. The control module is fixed inside the control cavity. The control module includes a main control board fixed to the top of the inner side of the control cavity. A transition unit is fixed below the main control board by bolts. The transition unit is connected to the main control board. The transition unit includes an intermediate plate. An optical communication receiving module and a wireless power supply coil are fixed on the bottom surface of the intermediate plate. A motor control board is fixed at the bottom of the control cavity. An encoder code disk, a wireless power receiving coil, and an optical communication transmitting module are fixed on the top of the motor control board. An encoder reading head that cooperates with the encoder code disk is fixed at the rotating end of the rotary motor.

[0014] Furthermore, an aviation connector is fixed to the top of the fuselage, and an LED indicator is fixed to the main control board, the LED indicator being fitted into the top of the fuselage.

[0015] Furthermore, the 3D measurement unit is used for weld seam inspection, and the laser displacement sensor also includes a weld field anti-interference unit, which includes a strong ambient light suppression submodule and a dual-wavelength fume compensation submodule. The strong ambient light suppression submodule includes a narrowband tunable filter precisely matched to the laser emission wavelength, an automatic exposure control circuit, and a laser power adaptive adjustment circuit. The dual-wavelength fume compensation submodule integrates two laser optical paths of different wavelengths, one being a 650nm measurement laser and the other being an 850nm near-infrared compensation laser, which are emitted coaxially with the measurement laser.

[0016] Furthermore, the control module and data processing module are connected to a multi-coordinate system fusion unit. This multi-coordinate system fusion unit interacts with the control systems of the industrial robot and linear motion platform in real time. It can receive real-time data from the robot's six-axis encoder and the motion platform's real-time pose data via EtherCAT and Profinet industrial buses. The multi-coordinate system fusion unit establishes a four-level coordinate transformation model comprising the sensor rotation coordinate system, the robot end effector coordinate system, the robot base coordinate system, and the workpiece coordinate system. It then performs nanosecond-level time synchronization between the X and Z contour data and rotation angle data collected in real-time by the sensors and the robot's real-time pose data. By integrating spatial coordinates, the system calculates the three-dimensional coordinates of the measured point in the workpiece's global coordinate system in real time, solving the coordinate coupling problem between robot motion and sensor rotation. Based on this architecture, the system can achieve online continuous 3D measurement while moving, rotating, and measuring during the robot's dynamic movement process, without requiring the robot to stop for scanning. It can complete continuous positioning and inspection of long and complex welds, fully adapting to the non-stop operation requirements of automated production lines. At the same time, the data processing module can feed back the extracted weld feature data to the robot control system in real time through the industrial bus, realizing closed-loop control of the entire process of weld positioning, trajectory planning, welding execution, and post-weld inspection.

[0017] Furthermore, the data processing module incorporates a lightweight weld recognition model, which automatically identifies the weld type based on the acquired contour data and extracts multiple weld features in a single measurement. These weld features include the weld center, weld edge, weld depth, and weld width.

[0018] Compared with existing technologies, the rotary 3D contour measurement system of the present invention, through the combination of a rotary structure, a built-in angle encoder, a linear CMOS array, and an adjustable angle reflector, has the following advantages:

[0019] 1. Simple system: The system adopts a rotary design, which rotates the 2D profiler to form a 3D profile. No external encoder is required, which simplifies the system structure and reduces costs.

[0020] 2. Lower cost: Using a linear CMOS sensor instead of a planar CMOS sensor reduces costs and simplifies data processing.

[0021] 3. High efficiency: It can simultaneously detect multiple feature points of the weld, such as the weld center, weld edge, weld depth, and weld width; the measurement efficiency is greatly improved.

[0022] 4. High measurement accuracy: Through rotational scanning, complete 360° contour information can be obtained, resulting in high measurement accuracy.

[0023] 5. Wide range of applications: Suitable for various industrial applications such as weld seam location, contour inspection, and quality control.

[0024] 6. Adjustable scanning range: The laser displacement sensor uses an adjustable angle reflector, which can adjust the diameter of the scanning circle to adapt to objects of different sizes.

[0025] 7. The system can control the variation of the circle diameter with distance to adapt to measurement needs in different height ranges: By adjusting the angle between the measurement height and the adjustable-angle reflector, the system can control the scanning circle diameter at different measurement distances. A small circle diameter is used to measure small height features at close distances, while a large circle diameter is used to measure large height features at long distances. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the overall module connection structure of the rotary 3D contour measurement system of the present invention.

[0027] Figure 2 This is a schematic diagram showing the connection structure of each module in the rotary 3D contour measurement system of the present invention.

[0028] Figure 3 This is a schematic diagram of the optical path structure of the laser displacement sensor of the present invention.

[0029] Figure 4 This is a schematic diagram of the overall structure of the adjustable angle reflector of the present invention.

[0030] Figure 5 This is a top view schematic diagram of the adjustable angle reflector structure of the present invention.

[0031] Figure 6 This is a schematic diagram of the overall structure of the rotary 3D contour measurement system of the present invention.

[0032] Figure 7 This is a schematic diagram of the control flow of the rotary 3D contour measurement system of the present invention.

[0033] Figure 8 This is a schematic diagram of the rotary 3D contour measurement system of the present invention used for weld seam location.

[0034] Reference numerals: 1. Body, 2. Laser displacement sensor, 3. Adjustable angle reflector, 31. Angle adjustment seat, 32. Reflector, 33. Pin hole, 34. Angle adjustment arc hole, 35. Pin shaft, 36. Locking bolt, 4. Measured object, 5. Laser emitter, 6. Centerline, 7. Imaging module, 8. Protective cover, 9. Protective lens, 10. Detection chamber, 11. Control chamber, 12. Main control board, 13. Transition unit, 14. Motor control board, 15. Encoder disk, 16. Aviation connector, 17. Rotary motor. Detailed Implementation

[0035] like Figures 1 to 8The rotary 3D contour measurement system shown includes a body 1, on the inner side of which a 3D measurement unit is installed. The 3D measurement unit includes:

[0036] A laser displacement sensor 2 is used to measure the contour information of the measured object in the X and Z directions. The laser displacement sensor 2 has a built-in adjustable angle reflector 3, which forms an angle α of 5° to 20° with the axis 6 of the laser displacement sensor 2. After angle adjustment, the reflector is fixed. The adjustable angle reflector 3 includes an angle adjustment base 31, on which a reflector 32 is fixed. The reflecting surface of the reflector 32 is positioned on the light output path of the laser emitter 5. The angle adjustment base 31 has a pin hole 33 and two angle adjustment arc holes 34. The pin hole 34 is hinged to the base inside the laser displacement sensor 2 via the pin shaft 35. A locking bolt 36 is installed inside the angle-adjusting arc-shaped hole 34, and the locking bolt 36 is screwed and tightened to the base. When the laser displacement sensor 2 is adjusted, the locking bolt 36 is loosened, pushing the angle-adjusting seat 31. At this time, the angle-adjusting seat 31 rotates along the pin shaft 35, and the angle-adjusting arc-shaped hole 34 of the angle-adjusting seat 31 swings in an arc along the locking bolt 36. When one end of the angle-adjusting arc-shaped hole 34 swings and engages with the locking bolt 36, the adjustable angle reflector 3 forms a 5° angle with the axis of the laser displacement sensor 2. When the other end of the angle-adjusting arc-shaped hole 34 swings and engages with the locking bolt 36, the adjustable angle reflector 3 forms a 5° angle with the axis of the laser displacement sensor 2. The mirror 3 and the axis of the laser displacement sensor 2 form a 20° angle. After the swing seat completes its rotation, the angle adjustment seat is locked to the base by the locking bolt 36, thus completing the angle adjustment. When the entire laser displacement sensor 2 rotates around its axis, due to the presence of the angle α, the diameter of the scanning circle varies with the measurement distance: the closer the distance, the smaller the circle; the farther the distance, the larger the circle. The effective measurement range is 350±250mm (100mm-600mm), with a near-end circle diameter of 35mm and a far-end circle diameter of 100mm. The laser displacement sensor 2 uses a linear array CMOS sensor, as shown in the image... The prime numbers are 1024-4096, and the measurement frequency is 3000-10000Hz (preferred value: 5000Hz) to meet the requirements of high-speed rotation measurement; the laser emitter 5 emits a modulated beam, which is reflected by the adjustable angle reflector 3 to form a point laser spot. The reflected beam enters the object under test 4. When the entire sensor rotates around the sensor axis 6, due to the angle α between the adjustable angle reflector 3 and the axis 6, the trajectory of the point laser in space forms a rotating scanning circle. Then, the laser beam reflected back from the object under test 4 (diffuse reflection) enters the sensor's imaging module 7 (linear array CMOS sensor) to achieve reflected light collection and imaging.

[0037] A rotary drive mechanism includes a rotary motor 17 fixed inside the machine body 1; an angle encoder is mounted on the rotating end of the rotary motor 17; the rotating end of the rotary motor 17 is fixed to the center of the rotating platform; a laser displacement sensor 2 is fixedly mounted on the bottom of the rotating platform; when the rotary drive mechanism drives the laser displacement sensor 2 to rotate, due to the angle between the adjustable angle reflector 3 and the vertical axis, the trajectory of the laser line in space forms a circle, and the diameter of the circle varies with the measurement distance; the rotary motor 17 drives the rotating platform to rotate, with a rotation speed range of 100-3000 rpm; the laser displacement sensor 2 is fixedly mounted on the rotating platform and rotates together with the rotating platform; the angle encoder is used to detect the rotation angle in real time, with an angle detection accuracy of 0.01°-0.1°; it is used to detect the rotation angle in real time and feed the angle information back to the control module;

[0038] The control module calculates the three-dimensional coordinates of the surface of the object 4 under test through coordinate transformation based on the rotation angle and the measurement data of the laser displacement sensor 2. The control module is connected to the rotation drive mechanism and the laser displacement sensor 2 respectively. The control module is used to control the rotation speed of the rotary motor 17 and the measurement parameters of the laser displacement sensor 2, and to receive the measurement data of the laser displacement sensor 2 and the angle information of the angle encoder.

[0039] The data processing module, which is electrically connected to the control module, is used to calculate the three-dimensional contour information of the surface of the object under test 4 through coordinate transformation based on the rotation angle and the measurement data of the laser displacement sensor 2. The data processing module calculates the three-dimensional contour information (X, Y, Z coordinates) of the surface of the object under test 4 through coordinate transformation based on the rotation angle and the measurement data of the laser displacement sensor 2, with a measurement accuracy of ±0.01-0.05mm.

[0040] The front end of the body 1 is fixed with a protective cover 8 via a flange, and a protective lens 9 is fixed inside the protective cover 8. The body 1 includes a detection cavity 10 and a control cavity 11 fastened by bolts. The control module is fixed inside the control cavity 11. The control module includes a main control board 12 fixed to the top of the inner side of the control cavity 11. A transition unit 13 is fixed below the main control board 12 via bolts. The transition unit 13 is connected to the main control board 12. The transition unit 13 includes an intermediate plate. An optical communication receiving module and a wireless power supply coil are fixed on the bottom surface of the intermediate plate. A motor control board 14 is fixed at the bottom of the control cavity 11. An encoder disk 15, a wireless power receiving coil, and an optical communication transmitting module are fixed on the top of the motor control board 14. An encoder reading head that cooperates with the encoder disk 15 is fixed at the rotating end of the rotary motor 17. An aviation connector 16 is fixed on the top of the body 1. An LED indicator is fixed on the main control board 12 and is embedded in the top of the body 1.

[0041] The laser displacement sensor 2 rotates together with the rotating platform to perform a 360° scan of the object under test 4. During the rotation, due to the angle α between the adjustable angle reflector 3 and the vertical axis, the trajectory of the laser line in space forms a circle, and the diameter of the circle varies with the measurement distance (35mm at the near end and 100mm at the far end). The laser displacement sensor 2 continuously measures the contour information in the X and Z directions, the angle encoder detects the rotation angle θ in real time, and the data processing module calculates the Y coordinate through coordinate transformation, and finally synthesizes a three-dimensional contour point cloud. Through 360° rotation scanning, the complete three-dimensional contour information of the surface of the object under test 4 can be obtained, and multiple weld features can be detected simultaneously in one measurement.

[0042] The control module acquires the rotation angle collected by the angle encoder and the measurement data from the laser displacement sensor 2, and calculates the three-dimensional coordinates of the surface of the object 4 under test through coordinate transformation. Specifically, the X and Z coordinates are measured by the laser displacement sensor 2: X coordinate: directly measured by the laser displacement sensor 2, representing the displacement along the laser line direction, with a measurement accuracy of ±0.01-0.05mm; Z coordinate: directly measured by the laser displacement sensor 2, representing the displacement (height) perpendicular to the laser line, with a measurement accuracy of ±0.01-0.05mm; Y coordinate: calculated based on the rotation angle θ and the scanning radius R, Y=R×sin(θ), representing the position in the rotation direction, with measurement accuracy depending on the accuracy of the angle encoder, where θ is the rotation angle and R is the scanning radius.

[0043] Example 1:

[0044] The rotary 3D contour measurement system of the present invention includes a laser displacement sensor 2, a rotation drive mechanism, a control module and a data processing module;

[0045] The laser displacement sensor 2 adopts an adjustable angle reflector 3 and includes a laser emission module, an adjustable angle reflector 3, an imaging module 7 and a signal processing module; the laser displacement sensor 2 is used to measure the contour information of the measured object 4 in the X and Z directions; the linear array CMOS sensor has a measurement frequency of 5000Hz to meet the requirements of high-speed rotation measurement.

[0046] The rotary drive mechanism includes a rotary motor 17, a rotary platform, and an angle encoder; the rotary motor 17 is a stepper motor that drives the rotary platform to rotate. The laser displacement sensor 2 is fixedly mounted on the rotary platform and rotates with it; the angle encoder is used to detect the rotation angle in real time and feed the angle information back to the control module.

[0047] The control module uses an embedded controller, which is installed with the rotary drive mechanism and the laser displacement sensor 2. It is used to control the rotation speed of the rotary motor 17 and the measurement parameters of the laser displacement sensor 2, and to receive the measurement data from the laser displacement sensor 2. The control module records the rotation angle of each measurement point in real time based on the angle information fed back by the angle encoder.

[0048] The data processing module is electrically connected to the control module and uses an industrial computer or high-performance processor to calculate the three-dimensional contour information of the surface of the object being measured 4 based on the rotation angle and the measurement data of the laser displacement sensor 2. The specific working parameters of the measurement system are shown in Table 1.

[0049] Table 1: Key Parameter Ranges and Optimal Values

[0050]

[0051] The working process of the rotary 3D contour measurement system of the present invention is as follows:

[0052] Step 1, System Initialization: The control module initializes the rotary motor 17, angle encoder and laser displacement sensor 2; sets the rotation speed (100-3000rpm, preferred value: 1000-2000rpm) and sets the measurement parameters of the laser displacement sensor 2 (measurement frequency 5000Hz, measurement range 100-400mm).

[0053] Step 2, Rotation Scan Start: Rotary motor 17 drives the rotary platform to start rotating; laser displacement sensor 2 rotates together with the rotary platform; angle encoder detects the rotation angle θ in real time, with an angle detection accuracy of 0.05°;

[0054] Step 3, laser line scanning to form a circle: Laser displacement sensor 2 emits a laser line. Due to the 5°-20° angle between the adjustable angle reflector 3 and the orthocenter, the trajectory of the laser line in space forms a circle. The diameter of the circle varies with the measurement distance: the closer to the sensor, the smaller the circle (35mm at 100mm from the near end); the farther from the sensor, the larger the circle (100mm at 400mm from the far end). Effective measurement range: 350±250mm (100mm-600mm).

[0055] Step 4, Continuously measure the X and Z direction contours: During rotation, the laser displacement sensor 2 continuously measures the contour information of the object 4 in the X and Z directions; Measurement frequency: 5000Hz (number of measurement points per revolution = 5000 / (rotation speed / 60)); For example: at a rotation speed of 1000rpm, 300 points are measured per revolution (5000 / (1000 / 60) = 300); X coordinate: displacement along the laser line direction, measurement accuracy ±0.01mm; Z coordinate: displacement (height) perpendicular to the laser line, measurement accuracy ±0.01mm;

[0056] Step 5, synchronous acquisition of angle information: The angle encoder detects the rotation angle θ in real time with an angle detection accuracy of 0.05°; the control module synchronously records the rotation angle θ and the corresponding X and Z coordinates of each measurement point; the range of angle θ is 0°-360° (or -180°-180°).

[0057] Step 6, coordinate transformation to calculate Y coordinate: The data processing module calculates the Y coordinate based on the rotation angle θ and the scanning radius R. The formula for calculating the Y coordinate is: Y = R × sin(θ), where R is the scanning radius, which is determined by the measurement distance and the included angle α of the adjustable angle reflector 3. The range of the scanning radius R is calculated based on the measurement distance and the included angle α, with a typical value of 10-200mm.

[0058] Step 7, 3D coordinate synthesis: The data processing module synthesizes the X, Y, and Z coordinates into a 3D contour point cloud. Each measurement point corresponds to a 3D coordinate (X, Y, Z). Through 360-degree rotation scanning, the complete 3D contour point cloud of the surface of the measured object is obtained.

[0059] Step 8, 3D contour reconstruction: The data processing module performs post-processing on the 3D contour point cloud: Point cloud filtering: removes noise points; Point cloud registration: aligns data from multiple scanning cycles; Surface reconstruction: generates a 3D surface model; Outputs 3D contour data, which can be used for subsequent analysis and applications;

[0060] Step 9, Weld Feature Extraction (Weld Positioning Application): The data processing module extracts weld features from the 3D contour data, including weld center: detecting the lowest point or centerline of the weld to determine the center position of the weld (X,Y coordinates); weld edge: detecting abrupt change points on both sides of the weld to determine the edge position of the weld; weld depth: calculating the height difference between the lowest point of the weld and the highest points on both sides (Z coordinate difference); weld width: calculating the distance between the edges on both sides of the weld (X coordinate difference); 2-3 weld features can be detected simultaneously in one measurement, improving efficiency by 2-3 times.

[0061] The laser displacement sensor 2 rotates with the rotating platform to perform a 360-degree scan of the object under test 4. During the rotation, due to the angle α between the adjustable angle reflector 3 and the vertical axis, the trajectory of the laser line in space forms a circle, the diameter of which varies with the measurement distance (35mm at the near end and 100mm at the far end). The laser displacement sensor 2 continuously measures the contour information in the X and Z directions, the angle encoder detects the rotation angle θ in real time, and the data processing module calculates the Y coordinate through coordinate transformation, finally synthesizing a three-dimensional contour point cloud. Through 360-degree rotational scanning, complete three-dimensional contour information of the surface of the object under test 4 can be obtained, and multiple weld features can be detected simultaneously in a single measurement.

[0062] like Figure 6 As shown, the rotary 3D contour measurement system of the present invention is used for weld seam location applications. When applied to weld seam location, the system can simultaneously measure and detect multiple weld seam features in one operation.

[0063] 1. Weld center: The center position of the weld is determined by detecting the lowest point or center line of the weld;

[0064] 2. Weld edge: The edge position of the weld is determined by detecting abrupt changes on both sides of the weld.

[0065] 3. Weld depth: The weld depth is determined by measuring the height difference between the lowest point of the weld and the highest points on both sides;

[0066] 4. Weld width: The width of the weld is determined by detecting the distance between the two edges of the weld. Compared with traditional weld tracking systems that can only detect one weld feature at a time, this system can detect 2-3 weld features at a time, improving efficiency by 2-3 times.

[0067] Example 2:

[0068] The rotary 3D contour measurement system of the present invention adopts a low-speed rotation configuration and is suitable for precision measurement applications; specific parameters are as follows:

[0069] Rotary motor 17: Stepper motor, rotation speed 100-500rpm (preferred value: 300rpm); Angle encoder: High-precision encoder, angle detection accuracy 0.01°; Laser displacement sensor 2: Linear array CMOS 4096 pixels, measurement frequency 3000Hz; Adjustable angle reflector 3, included angle α: 5° (minimum angle); Effective measurement range: 100-300mm (smaller range); Near-end circle diameter (100mm distance): 25mm; Far-end circle diameter (300mm distance): 70mm; X and Z direction measurement accuracy: ±0.01mm; Y direction measurement accuracy: ±0.02mm (high-precision angle encoder); Number of measurement points per revolution: 600 points (3000 / (300 / 60)=600);

[0070] Compared with Example 1, the rotary 3D contour measurement system of Example 2 has the following differences: lower rotation speed (300rpm vs 1500rpm), but higher measurement accuracy; higher angle encoder accuracy (0.01° vs 0.05°); more linear CMOS pixels (4096 vs 2048); adjustable angle reflector 3 with an included angle α=5° (minimum angle), forming a smaller scanning circle; smaller effective measurement range (100-300mm), suitable for close-range precision measurement. Based on the above differences, the rotary 3D contour measurement system of Example 2 has the following advantages: highest measurement accuracy: ±0.01mm in X and Z directions, ±0.02mm in Y direction; most measurement points per revolution: 600 points, high point cloud density; suitable for precision measurement: applicable to high-precision contour detection and scientific research measurement; slower measurement speed: but high accuracy, suitable for applications with high accuracy requirements.

[0071] Example 3:

[0072] The rotary 3D contour measurement system of the present invention adopts a high-speed rotation configuration, which is suitable for rapid scanning applications. The specific configuration is as follows:

[0073] Rotary motor 17: Servo motor, rotation speed 2000-3000rpm (preferred value: 2500rpm); Angle encoder: Standard encoder, angle detection accuracy 0.1°; Laser displacement sensor 2: Linear array CMOS 1024 pixels, measurement frequency 10000Hz; Adjustable angle reflector 3, included angle α: 20° (maximum angle); Effective measurement range: 150-500mm (larger range); Near-end circle diameter (150mm distance): 40mm; Far-end circle diameter (500mm distance): 150mm; X and Z direction measurement accuracy: ±0.05mm; Y direction measurement accuracy: ±0.1mm (standard angle encoder); Number of measurement points per revolution: 240 points (10000 / (2500 / 60)=240);

[0074] Compared with Example 1, the rotary 3D contour measurement system of Example 2 has the following differences: higher rotation speed (2500rpm vs. 1500rpm), faster measurement speed; lower angle encoder accuracy (0.1° vs. 0.05°), but still meets the requirements for rapid scanning; fewer linear CMOS pixels (1024 vs. 2048), but higher measurement frequency (10000Hz vs. 5000Hz); adjustable angle reflector 3 with an included angle α = 20° (maximum angle), forming a larger scanning circle; larger effective measurement range (150-500mm), suitable for long-distance rapid scanning. Based on the above differences, the rotary 3D contour measurement system of Example 3 has the following advantages: fastest measurement speed: rotation speed 2500rpm, measurement frequency 10000Hz; high scanning efficiency: quickly obtains 3D contour data; suitable for rapid scanning: applicable to rapid inspection and dynamic measurement on production lines; slightly lower measurement accuracy: but still meets the requirements for rapid scanning.

[0075] Example 4:

[0076] The difference between this embodiment and Embodiment 1 is that the data processing module uses an FPGA for real-time data processing, resulting in faster processing speed and real-time display of 3D contour information. Its specific configuration is as follows: Data processing module 15: FPGA (Xilinx Zynq-7000 series); Processing speed: Real-time processing, latency <10ms; Other parameters are the same as in Embodiment 1; It has the following advantages: Fastest processing speed: FPGA parallel processing, real-time display of 3D contours; Minimal latency: Processing latency less than 10ms, suitable for real-time control applications; Applicable to application scenarios requiring real-time feedback, such as robotic welding and real-time quality control.

[0077] Example 5:

[0078] The difference between this embodiment and Embodiment 1 is that the system also includes a display module for real-time display of three-dimensional contour information and measurement results, facilitating observation and analysis by operators. The display module uses a 10.1-inch touchscreen with a resolution of 1920×1200. The display content includes three-dimensional contour visualization, weld feature annotation, and other parameters of measurement data, which are the same as in Embodiment 1. This embodiment has the following advantages: it can intuitively display three-dimensional contours and measurement results, is touchscreen operated, and has a user-friendly human-computer interaction; it is suitable for application scenarios that require manual observation and analysis.

[0079] The performance test results for Example 1 are as follows:

[0080] I. Rotational scanning accuracy test:

[0081] Test standards: GB / T26111-2010 "Laser Displacement Sensors 2", ISO10360 "Coordinate Measuring Machines - Acceptance and Re-inspection" test methods:

[0082] First, a standard sphere (50mm in diameter, ±0.001mm accuracy) was fixed on the test platform. Second, the system performed a 360-degree rotation scan of the standard sphere. Third, the three-dimensional contour of the standard sphere was measured, and the center position and radius were calculated. Finally, the measurement error was calculated by comparing the result with the standard value. The test results are as follows:

[0083] X-direction measurement accuracy: ±0.010mm (target value: ±0.01mm); Y-direction measurement accuracy: ±0.048mm (target value: ±0.05mm); Z-direction measurement accuracy: ±0.012mm (target value: ±0.01mm); Sphere center position error: ±0.015mm (target value: <0.02mm); Radius measurement error: ±0.008mm (target value: <0.01mm); As can be seen from the above, the test meets the application requirements.

[0084] II. Rotation speed and number of measurement points test:

[0085] The testing method is as follows: First, tests were conducted at different rotational speeds (100 rpm, 500 rpm, 1000 rpm, 2000 rpm, 3000 rpm); second, the number of measurement points per revolution was measured: number of measurement points = measurement frequency / (rotational speed / 60); finally, the uniformity and completeness of the measurement points were verified; the test results (measurement frequency 5000 Hz) are as follows:

[0086] 100 rpm: 3000 points per revolution (target value: 3000 points); 500 rpm: 600 points per revolution (target value: 600 points); 1000 rpm: 300 points per revolution (target value: 300 points); 2000 rpm: 150 points per revolution (target value: 150 points); 3000 rpm: 100 points per revolution (target value: 100 points); Uniformity of measurement points: coefficient of variation CV < 5% (target value: CV < 10%). As can be seen from the above, the test meets the application requirements.

[0087] III. Weld Feature Detection and Testing:

[0088] The testing method is as follows: First, prepare a standard weld specimen (V-shaped weld, depth 5mm, width 10mm). Second, the system performs a 360-degree rotation scan of the weld. Third, extract weld features from the 3D contour data: weld center position (X, Y coordinates), weld edge position, weld depth (Z coordinate difference), and weld width (X coordinate difference). Finally, compare with the standard values ​​to calculate the detection error. The test results are as follows:

[0089] Weld center position error: ±0.02mm (target value: <0.05mm); Weld edge detection error: ±0.03mm (target value: <0.05mm); Weld depth measurement error: ±0.015mm (target value: <0.02mm); Weld width measurement error: ±0.025mm (target value: <0.05mm); Number of features detectable in one measurement: 2-3 (target value: 2-3).

[0090] IV. Scanning circle diameter test:

[0091] The testing method is as follows: First, tests were conducted at different measurement distances (100mm, 200mm, 300mm, 400mm); second, the diameter of the resulting scanning circle was measured; finally, the relationship between the circle diameter and the distance was verified; the test results (angle α = 12°) are as follows:

[0092] 100mm distance: circle diameter 35mm (target value: 35mm); 200mm distance: circle diameter 57mm (target value: 57mm); 300mm distance: circle diameter 78mm (target value: 78mm); 400mm distance: circle diameter 100mm (target value: 100mm); where, the relationship between circle diameter and distance is: D=35+65×(L-100) / 300, where D is the circle diameter (mm) and L is the measured distance (mm).

[0093] V. System Stability Test:

[0094] The test parameters are as follows: First, temperature stability: tested every 10℃ within the temperature range of -10℃ to +60℃; second, time stability: tested hourly for 24 hours of continuous operation; third, vibration stability: tested under vibration frequency of 10-2000Hz and acceleration of 2g; the test results are as follows:

[0095] Temperature stability: Measurement accuracy variation <10% (target value: <15%); Time stability: Measurement accuracy variation <5% (target value: <10%); Vibration stability: Measurement accuracy variation <8% (target value: <15%).

[0096] The experimental data comparing the performance parameters of Example 1 with those of the prior art are as follows:

[0097] Comparison Scheme 1: 2D profilometer + external encoder, model: KeyenceLJ-V7080 + external rotary encoder, features: 2D profilometer combined with external encoder to achieve 3D measurement; Comparison Scheme 2: Area array CMOS 3D profilometer, model: Gocator3210, features: area array CMOS, 3D profilometer measurement; Comparison Scheme 3: Traditional weld seam tracking system, model: SICK weld seam tracking sensor, features: single point or single line laser, detects one weld seam feature at a time; Comparison Scheme 4: The rotary 3D profilometer measurement system of the present invention (Example 1), linear array CMOS, detects multiple weld seam features at a time.

[0098] Table 2: Comparative Experiment Data Table

[0099]

[0100] This invention is the first to integrate an angle encoder into a rotary drive mechanism, eliminating the need for an external encoder. It employs a linear CMOS array and rotary scanning to achieve 3D contour measurement, obtaining a complete 3D contour. Multiple weld features can be detected simultaneously in a single measurement. The invention utilizes an adjustable-angle reflector 3 to allow the circle diameter to vary with the measurement distance, adapting to measurement needs across different height ranges. It enables the simultaneous detection of multiple features and the variation of the circle diameter with distance. As shown in the comparative experimental data in Table 2, this invention is superior to or equivalent to existing technologies (which are more expensive) in terms of system complexity, cost, measurement accuracy, measurement speed, and the number of features detected in a single measurement. Specifically:

[0101] 1. The rotary 3D contour measurement system of the present invention has a built-in angle encoder, eliminating the need for an external encoder and minimizing system complexity;

[0102] 2. Lower cost: The cost of the rotating 3D contour measurement system of this invention is 70% lower than that of area array CMOS;

[0103] 3. High measurement accuracy: ±0.01mm in the X and Z directions, comparable to area array CMOS; compared to other measurement systems.

[0104] 4. High measurement speed: The measurement frequency is 5000Hz, which is 2.5 times faster than that of a CMOS array.

[0105] 5. High efficiency: Multiple weld features can be detected simultaneously in one measurement, which is many times more efficient than detecting a single weld feature.

[0106] 6. Adjustable scanning range: The circle diameter varies with distance (35-100mm), making it highly adaptable.

[0107] Example 6:

[0108] This embodiment, based on Embodiment 1, adds a welding field anti-interference unit, enabling it to be used in core application scenarios such as welding positioning and post-weld inspection. It represents a specific upgrade in anti-interference capabilities to solve measurement interference problems caused by strong arc light and high levels of smoke at the welding site. Specifically, the laser displacement sensor 2 further includes a welding field anti-interference unit, which comprises a strong ambient light suppression submodule and a dual-wavelength smoke compensation submodule. The strong ambient light suppression submodule includes a narrowband tunable filter precisely matched to the laser emission wavelength, an automatic exposure control circuit, and a laser power adaptive adjustment circuit. The narrowband tunable filter has a half-width at half-maximum (WHM) of... With a wavelength ≤10nm, it can accurately transmit the measurement laser wavelength while filtering out broadband interference from welding arc light, achieving an ambient light suppression ratio ≥60dB. The automatic exposure control circuit and laser power adaptive adjustment circuit are linked, dynamically adjusting the CMOS exposure time and laser emission power based on the detected ambient light intensity. In strong arc light environments, it automatically increases laser power and shortens exposure time to maximize arc light interference suppression and avoid measurement failures caused by image overexposure. The dual-wavelength smoke compensation submodule integrates two laser optical paths of different wavelengths: one is a 650nm red measurement laser used for contour acquisition of the measured object; the other... The optical path uses an 850nm near-infrared compensation laser, emitted coaxially with the measurement laser, to detect the concentration of welding fumes and water mist in the optical path. The data processing module calculates the fume concentration in the optical path based on the echo attenuation of the compensation laser, establishes a scattering error correction model, and corrects in real time the contour data jumps and measurement errors caused by fume scattering of the measurement laser, ensuring measurement accuracy in high-fume environments. Simultaneously, the data processing module in this embodiment incorporates a lightweight weld seam recognition model, which can automatically identify common industrial weld seam types such as V-type, U-type, lap joints, and corner joints. Two to three weld seam features can be extracted simultaneously in a single measurement. Weld features include weld center, weld edge, weld depth, and weld width. Compared with traditional weld tracking systems, efficiency is greatly improved, and it can effectively filter out abnormal points such as welding spatter and slag, accurately extract weld features, and ensure feature detection accuracy of ≥99.5% in harsh welding environments. It can solve the problems of measurement failure and inaccurate data of existing general profilometers in the environment of strong arc light and high dust, greatly improving the applicability and stability of the system on the welding site. No additional protective or light-shielding devices are required. It can be directly installed on welding robots to realize online weld positioning and post-weld inspection, and has extremely strong scene adaptability.

[0109] Example 7:

[0110] This embodiment, based on Embodiment 1, adds a multi-coordinate system fusion unit. It addresses multi-coordinate system fusion and dynamic measurement in industrial robot automated welding and online robot inspection scenarios. The specific structure is as follows: The control module and data processing module are connected to the multi-coordinate system fusion unit. This unit interacts with the control systems of the industrial robot and linear motion platform in real time, receiving real-time data from the robot's six-axis encoder and the motion platform's real-time pose data via EtherCAT and Profinet industrial buses. The multi-coordinate system fusion unit establishes a four-level coordinate transformation model: sensor rotation coordinate system, robot end effector coordinate system, robot base coordinate system, and workpiece coordinate system. It performs nanosecond-level time synchronization and spatial coordinate fusion of the X and Z contour data and rotation angle data collected in real-time by the sensors with the robot's real-time pose data, calculating the three-dimensional coordinates of the measured point in the workpiece's global coordinate system in real time, thus solving the problem of machine... This system addresses the coordinate coupling problem between robot motion and sensor rotation. Based on this architecture, it enables continuous online 3D measurement during the robot's dynamic movement, allowing for simultaneous movement, rotation, and measurement without requiring the robot to stop for scanning. This allows for continuous positioning and inspection of long and complex welds, fully adapting to the non-stop operation requirements of automated production lines. Simultaneously, the data processing module feeds back the extracted weld feature data to the robot control system in real-time via an industrial bus, achieving closed-loop control of the entire process, including weld positioning, trajectory planning, welding execution, and post-weld inspection. By integrating rotary 3D measurement with industrial robot motion control, the system solves the coordinate coupling error problem of multiple moving bodies, overcoming the limitation of static scanning in the original solution and expanding its application in automated welding production lines and online robot inspection scenarios. Furthermore, it establishes a complete closed-loop with the robot control system, significantly improving the intelligence level of welding automation and possessing extremely high industrial application value.

[0111] The specific working process of this embodiment is as follows: First, the robot control system is used as the PTP master clock and the FPGA is used as the PTP slave clock. Clock synchronization is achieved through the EtherCAT bus. Then, based on the calibrated 100MHz synchronous reference clock, the FPGA realizes the acquisition of the same clock edge of the laser displacement sensor (X / Z data), angle encoder (θ data), and EtherCAT bus (robot pose data) through hardware triggering. Next, the FPGA adds nanosecond-level resolution timestamps to each set of synchronously acquired multi-source data (X / Z, θ, robot pose). Then, the coordinate fusion operation area in the FPGA performs coordinate system fusion on the synchronously acquired and tagged multi-source data to complete the four-level coordinate transformation. Finally, the closed-loop control of the robot is realized.

[0112] The EtherCAT bus clock synchronization process is as follows:

[0113] Clock reception: The PTP physical layer chip transmits the PTP synchronization message (including timestamp) of the robot's master clock to the FPGA through the GMII interface. The transmission delay is detected and compensated in real time by the FPGA logic.

[0114] Phase calibration: The FPGA compares the phase of the local OCXO crystal clock with the PTP master clock, calculates the clock deviation (Δt), and adjusts the phase and frequency of the local clock in real time through a digital phase-locked loop (DLL) to achieve nanosecond-level alignment with the master clock, with the clock deviation controlled within ±5ns.

[0115] Clock distribution: The FPGA distributes the calibrated synchronous clock (100MHz, clock period 10ns) to all on-chip logic areas, as well as external laser displacement sensors and angle encoders, as a unified synchronous reference clock.

[0116] The specific details of acquiring multi-source data on the same clock edge are as follows:

[0117] Trigger signal generation: The FPGA generates an LVDS differential trigger signal at each rising edge of the synchronous clock (10ns interval) and sends it to the trigger input terminals of the laser displacement sensor and the angle encoder.

[0118] Synchronous sampling: After receiving the trigger signal, the laser displacement sensor and angle encoder complete the sampling of X / Z contour data and rotation angle θ on the same clock edge, and transmit the sampled data back to the FPGA in real time through the LVDS interface;

[0119] Robot pose data reception: The EtherCAT bus logic receives six-axis encoder pose data from the robot control system on the same clock edge and transmits it directly to the FPGA through the on-chip FIFO interface, eliminating the delay deviation of bus reception;

[0120] Hardware latching: The FPGA trigger acquisition logic completes hardware latching of all data 2ns after the trigger clock edge, ensuring that the multi-source data are acquired at the same time point and there is no time deviation.

[0121] The process of adding nanosecond-level resolution timestamps to multi-source data is as follows:

[0122] Timestamp Counter: A 64-bit nanosecond-level timestamp counter is built into the FPGA, driven by a synchronous reference clock, with a counting resolution of 1ns, and is fully synchronized with the PTP global clock;

[0123] Timestamp tagging: While the data is latched in the hardware, the timestamp counter binds the current count value (nanosecond level) to the data, with a tagging delay of ≤1ns;

[0124] Data caching: The tagged multi-source data is written into the FPGA's on-chip BRAM high-speed cache, with a read / write speed of ≤1ns, avoiding transmission delays in off-chip storage. The cached data is arranged in timestamp order, which facilitates subsequent coordinate fusion.

[0125] The FPGA performs a four-level transformation and fusion of multi-source data coordinates for marking as follows:

[0126] First, read the synchronization data (X / Z, θ, robot pose) from the on-chip BRAM, and verify the timestamp to ensure that the data are from the same point in time. Second, calculate the three-dimensional coordinates (Y=R×sinθ) in the sensor rotation coordinate system with a delay of ≤2ns. Next, perform four-level coordinate transformations in sequence: sensor rotation coordinate system, robot end effector coordinate system, robot end effector coordinate system, robot base coordinate system, and workpiece coordinate system. Finally, output the three-dimensional coordinates in the workpiece global coordinate system and transmit the data to the weld feature extraction process with a delay of ≤3ns.

[0127] Data transmission and reception between FPGA and robot control system enables closed-loop control of the robot:

[0128] Data transmission and reception: The EtherCAT physical layer chip directly transmits robot pose data to the FPGA's on-chip FIFO, and the FPGA completes data reading within one clock edge (10ns); the extracted weld feature data is directly written by the FPGA into the EtherCAT transmit buffer, and data transmission is completed within one clock edge (10ns).

[0129] Delay compensation: The FPGA logic detects the transmission delay of the EtherCAT bus in real time (a fixed value determined by the trace length) and incorporates the delay value into the coordinate fusion calculation to eliminate the time deviation of the bus transmission;

[0130] Closed-loop control feedback: Weld feature data is fed back to the robot control system via EtherCAT bus. The overall delay from data extraction to robot reception is ≤50ns, which meets the requirements of real-time closed-loop control.

[0131] The above embodiments are merely preferred embodiments of the present invention. Therefore, all equivalent changes or modifications made to the structure, features and principles described in the claims of the present invention are included within the scope of the present invention.

Claims

1. A rotary 3D contour measurement system, characterized in that: The machine body includes a 3D measurement unit installed inside the machine body, the 3D measurement unit comprising: A laser displacement sensor, which is used to measure the contour information of the object being measured in the X and Z directions; A rotary drive mechanism includes a rotary motor fixed inside the machine body; an angle encoder is installed on the rotating end of the rotary motor; the rotating end of the rotary motor is fixed to the center of the rotary platform; and a laser displacement sensor is fixedly installed at the bottom of the rotary platform. The control module is connected to the rotary drive mechanism and the laser displacement sensor respectively; The data processing module is electrically connected to the control module and is used to calculate the three-dimensional contour information of the surface of the object under test by coordinate transformation based on the measurement data of the rotation angle and the laser displacement sensor. The laser displacement sensor has an adjustable-angle reflector built in, which forms an angle of 5° to 20° with the axis of the laser displacement sensor. When the rotation drive mechanism drives the laser displacement sensor to rotate, due to the angle between the adjustable-angle reflector and the vertical axis, the trajectory of the laser line in space forms a circle, and the diameter of the circle varies with the measurement distance; the closer the distance, the smaller the circle; the farther the distance, the larger the circle. During detection, the object's 3D contour is obtained by moving, rotating, and measuring simultaneously. The adjustable angle reflector includes an angle adjustment base, on which a reflector is fixed. The reflective surface of the reflector is positioned on the light output path of the laser emitter. The angle adjustment base has one pin hole and two angle adjustment arc holes. The pin hole is hinged to the base inside the laser displacement sensor via a pin shaft. A locking bolt is provided in the angle adjustment arc holes, and the locking bolt is screwed and tightened to the base. The 3D measurement unit is used for weld seam inspection. The laser displacement sensor also includes a weld field anti-interference unit, which includes a strong ambient light suppression submodule and a dual-wavelength fume compensation submodule. The strong ambient light suppression submodule includes a narrowband tunable filter precisely matched to the laser emission wavelength, an automatic exposure control circuit, and a laser power adaptive adjustment circuit. The dual-wavelength fume compensation submodule integrates two laser optical paths of different wavelengths: one is a 650nm measurement laser, and the other is an 850nm near-infrared compensation laser, emitted coaxially with the measurement laser. It is used to detect the concentration of welding fumes and water mist in the optical path. The data processing module can calculate the fume concentration in the optical path based on the echo attenuation of the compensation laser, establish a scattering error correction model, and correct the contour data jumps and measurement errors caused by fume scattering of the measurement laser in real time. The control module and data processing module are connected to the multi-coordinate system fusion unit, which interacts with the control system of the industrial robot and the linear motion platform in real time.

2. The rotary 3D contour measurement system according to claim 1, characterized in that, The control module acquires the rotation angle collected by the angle encoder and the measurement data of the laser displacement sensor, and calculates the three-dimensional coordinates of the surface of the object being measured through coordinate transformation. The X and Z coordinates are measured by the laser displacement sensor, and the Y coordinate is obtained according to the formula: Y = R×sinθ, where θ is the rotation angle and R is the scanning radius.

3. The rotary 3D contour measurement system according to claim 1, characterized in that, The data processing module is an FPGA, which performs real-time data processing with a processing delay of less than 10ms; a protective cover is fixed to the front of the machine body via a flange, and a protective lens is fixed inside the protective cover.

4. The rotary 3D contour measurement system according to claim 1, characterized in that, The machine body includes a detection chamber and a control chamber fastened by bolts. The control module is fixed inside the control chamber. The control module includes a main control board fixed to the top of the inner side of the control chamber. A transition unit is fixed below the main control board by bolts. The transition unit is connected to the main control board. The transition unit includes an intermediate plate. An optical communication receiving module and a wireless power supply coil are fixed on the bottom surface of the intermediate plate. A motor control board is fixed at the bottom of the control chamber. An encoder code disk, a wireless power receiving coil, and an optical communication transmitting module are fixed on the top of the motor control board. An encoder reading head that cooperates with the encoder code disk is fixed at the rotating end of the rotary motor.

5. The rotary 3D contour measurement system according to claim 4, characterized in that, The top of the fuselage is fixed with an aviation connector, and the main control board is fixed with an LED indicator light, which is embedded in the top of the fuselage.

6. The rotary 3D contour measurement system according to claim 1, characterized in that, The data processing module has a built-in lightweight weld recognition model. The weld recognition model automatically identifies the weld type based on the acquired contour data and extracts multiple weld features at the same time in one measurement. The weld features include weld center, weld edge, weld depth, and weld width.

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