A laser sensor based noise reducing earphone housing size measurement device

Abstract

This invention relates to the field of laser measurement technology, specifically to a laser sensor-based device for measuring the dimensions of a noise-canceling headphone shell. The device includes a worktable with a rotating assembly at its center for adjusting the headphone shell's display posture. A rotating component, an inner lifting component, and an outer lifting component are sequentially arranged around the rotating assembly. A laser emitting device and a vision acquisition device are distributed on either side of the rotating assembly. Through automated motion control and optimized measurement path, rapid and comprehensive surface scanning can be achieved, significantly reducing the measurement time for a single piece and meeting the online inspection requirements of production lines. During scanning, if the camera loses its spot due to a sudden change in surface curvature, the system can immediately pause the inner lifting and start the outer lifting. A pull rod and sliding sleeve drive the acquisition carriage to slide along an arc-shaped guide rail, automatically switching the laser emission angle and acquisition angle between obtuse and acute angles to ensure the spot remains stably on the measured surface.

Description

Technical Field

[0001] This invention relates to the field of laser measurement technology, and more specifically, to a device for measuring the dimensions of a noise-canceling headphone shell based on a laser sensor. Background Technology

[0002] In the field of mechanical manufacturing, the dimensional accuracy of headphone shells is a key factor affecting product assembly quality and user experience. This is especially true for precision audio devices such as noise-canceling headphones, where the dimensional tolerances of the shells are even more stringent, directly impacting acoustic sealing performance and wearing comfort. Currently, the industry mainly uses contact measuring tools such as calipers and micrometers for dimensional inspection. While these methods are low-cost, they have significant technical limitations: First, contact measurement requires manual operation, resulting in low efficiency and poor repeatability. Second, the contact between the measuring probe and the workpiece causes wear, leading to a decrease in measurement accuracy over long-term use. Furthermore, measurements of complex curved surfaces have blind spots, making it difficult to obtain complete three-dimensional dimensional data. Although non-contact solutions based on ordinary optical measurement have emerged in recent years, they are susceptible to ambient light interference and lack sufficient measurement stability under industrial lighting conditions, making it difficult to meet the high accuracy requirement of ±0.05mm.

[0003] Chinese Patent Publication No. CN107270833A discloses a three-dimensional measurement system and method for complex curved surface parts. The measurement system includes an industrial robot, a controller, a data processing host computer, and a fixed support. A line laser scanning sensor is mounted on the fixed support. The industrial robot is used to clamp the workpiece and move it along a certain trajectory. The line laser scanning sensor acquires the contour point cloud data of the workpiece. A line laser is installed within the sensor, which emits a measurement laser beam that is incident on the surface of the workpiece. The sensor also includes an industrial camera for imaging the workpiece. This invention can measure the three-dimensional surface morphology of complex curved surface parts, such as blade-like parts, and features high flexibility, fast measurement speed, and high measurement accuracy, effectively improving the inspection efficiency of complex curved surface parts.

[0004] Chinese Patent Publication No. CN108053441B discloses a high-precision measurement method using laser triangulation. This method includes a variable-threshold sub-pixel gray-scale centroid extraction algorithm within the laser triangulation high-precision measurement method. It accurately removes interference from noise regions at the edge of the light spot on the gray-scale centroid extraction method using gradient thresholding and Gaussian fitting, while simultaneously enhancing the data density of the gray-scale centroid method using polynomial fitting interpolation. By improving the positioning accuracy of the light spot center, the measurement accuracy of the laser triangulation method is enhanced. It consists of two parts: a variable-threshold sub-pixel gray-scale centroid extraction algorithm and a CCD tilt angle error compensation model. The variable-threshold sub-pixel gray-scale centroid extraction algorithm sets the threshold using a gradient function and a Gaussian fitting algorithm.

[0005] The aforementioned technologies rely on robot end effector movement and spot center extraction algorithms, respectively, to scan the surface of complex objects, and have the following drawbacks:

[0006] Repeated localization and multi-view point cloud stitching techniques are difficult and have large errors, causing the size calculation to deviate from the true value;

[0007] Data gaps appear in the deep cavity and undercut areas due to light obstruction, making it impossible to reconstruct the complete geometric features;

[0008] Based on this, the present invention discloses a device for measuring the size of the shell of noise-canceling headphones based on a laser sensor. Summary of the Invention

[0009] To address the shortcomings of existing contact measurement methods mentioned in the background art, such as low efficiency of manual operation, decreased accuracy due to wear of the measuring probe, and blind spots in the measurement of complex curved surfaces, while ordinary optical measurement methods are difficult to meet high precision requirements, this invention provides a noise-canceling headphone shell size measuring device based on a laser sensor, including a worktable. The central area of ​​the worktable is provided with a rotating assembly for adjusting the display posture of the headphone shell. A rotating assembly, an inner lifting assembly, and an outer lifting assembly are arranged sequentially around the rotating assembly. A laser emitting device and a visual acquisition device are distributed on both sides of the rotating assembly, and the rotating assembly provides the basis for the circumferential scanning of the laser emitting device and the visual acquisition device.

[0010] When the rotating component drives the laser emitting device and the visual acquisition device to rotate, the inner lifting component can synchronously adjust the laser emission angle of the laser emitting device, and the outer lifting component can synchronously adjust the visual acquisition angle of the visual acquisition device. The inner lifting component and the outer lifting component independently adjust the laser emission angle and the visual acquisition angle, and work together with the rotating component to form a compound motion, so that the system can complete continuous measurement of the plane, curved surface and deep cavity area of ​​the earphone shell without blind spots and without breaks under the same reference.

[0011] When the angle between the laser emission angle of the laser emitting device and the visual acquisition angle of the visual acquisition device is an obtuse angle, the horizontal position detection of the headphone shell is achieved. By increasing the angle between the laser projection and the camera optical axis, a greater depth of field and a wider field of view are obtained, thereby prioritizing and stably covering the flat area of ​​the headphone shell.

[0012] When the angle between the laser emission angle of the laser emitting device and the visual acquisition angle of the visual acquisition device is an acute angle, the curved position detection of the earphone shell can be realized. When the curved surface changes abruptly or a deep cavity appears, the baseline can be shortened and the local resolution can be improved to ensure that the light spot can still be reliably captured in steep or narrow parts.

[0013] Based on this, the orderly switching between the two angles allows the device to take into account both large-area initial scanning and high-detail supplementary scanning within the same scanning cycle, achieving high-precision measurement without blind spots.

[0014] As a further improvement to this technical solution, the visual acquisition device includes a connecting plate, on which a path guide rail with an opening facing the earphone shell is fixed. A acquisition trolley that can slide along the path guide rail is provided on the outer side of the path guide rail. A camera facing the center of the path guide rail is fixed on the acquisition trolley. The acquisition trolley can drive the camera to continuously tilt and scan on the concentric arc by sliding along the guide rail. The opening of the guide rail is directly facing the earphone shell, and the camera always points to the center of the circle, ensuring that the center of the field of view coincides with the measurement area. With the help of a laser emitter, it can realize the acquisition of three-dimensional point cloud without blind spots and with high density.

[0015] As a further improvement to this technical solution, the rotating assembly includes a working frame fixed on the workbench, a swing frame rotatably connected between the inner walls of the two sides of the working frame, a first motor fixed on one side of the working frame, the output end of the first motor fixedly connected to the swing frame, a second motor fixed in the middle of the swing frame, and a positioning seat fixed at the output end of the second motor. The first motor drives the swing frame to swing around the X-axis, and the second motor then drives the positioning seat to rotate around the Z-axis. The two sets of orthogonal rotations combine to form a spherical motion, so that any curved surface of the earphone shell can be instantly oriented towards the laser and the camera.

[0016] In another technical solution, an X-axis rotation mechanism is fixed at the center of the workbench, and a Y-axis rotation mechanism is directly installed at its output end. The positioning seat is fixed to the end of the Y-axis rotation mechanism. The X-axis motor drives the Y-axis to pitch as a whole, and the Y-axis motor then drives the positioning seat to swing to the side. The two axes are orthogonally superimposed to achieve rapid switching of any posture of the spherical surface of the earphone shell.

[0017] As a further improvement to this technical solution, a receiving groove is provided on the side of the positioning seat away from the swing frame. Multiple threaded cylinders are distributed on the wall of the receiving groove. A lead screw is threadedly connected to the inside of each threaded cylinder. One end of the lead screw located in the receiving groove is rotatably connected to a pressure foot, and the other end of the lead screw is fixedly connected to a shank. Rotating the exposed shank allows for fine adjustment of the advance and retreat of each pressure foot. With the help of a vernier caliper, the geometric center and the axis of rotation are precisely aligned, ensuring that a unified benchmark can be established in one clamping, completely eliminating repeated positioning errors, and laying a solid foundation for subsequent high-precision 3D scanning.

[0018] As a further improvement to this technical solution, the laser emitting device includes a clamping fork, with a pin rotatably connected between the inner walls of the two sides of the clamping fork. A strip plate is rotatably sleeved on the outer side of the pin. A laser emitter is fixed at one end of the strip plate facing the earphone shell, and a sliding groove is provided at the other end of the strip plate. The linear displacement obtained by the sliding groove is converted into a continuous change in the pitch angle of the laser emitter. The laser pointing can be quickly and accurately adjusted with very few parts.

[0019] In another technical solution, the laser emitter can also be a line laser, which can directly form a continuous line spot on the surface of the earphone shell. A complete contour can be captured in a single scan, significantly reducing the number of rotations and shooting frames. It can quickly acquire high-density three-dimensional point clouds, further shortening the measurement cycle while maintaining accuracy.

[0020] As a further improvement to this technical solution, the rotating assembly includes an inner ring sleeved on the outside of the working frame and a third motor fixed on the worktable. The inner ring has a clamping fork and a connecting plate fixed on both sides respectively. The output end of the third motor is fixed with a gear. The outer peripheral wall of the inner ring is provided with an internal gear ring that meshes with the gear. The inner ring is directly driven by the third motor to rotate uniformly around the working frame, so that the laser emitting device and the vision acquisition device can synchronously complete a 360° circumferential scan.

[0021] As a further improvement to this technical solution, the inner lifting assembly includes an enclosing cylinder fixed to the upper side of the worktable. Multiple lifting devices are equidistantly arranged on the enclosing cylinder. A central ring is fixed between the output ends of the lifting devices. A sliding sleeve is slidably fitted on the outer side of the central ring. A side plate is fixed on the upper side of the sliding sleeve. A sliding column is fixed on one side of the side plate. The sliding column slides in the sliding groove of the strip plate, converting the linear motion of the central ring into continuous and precise adjustment of the pitch angle of the laser emitter. This enables rapid and stepless changes in the laser angle, ensuring real-time synchronization with rotational scanning and providing stable and reliable angle control for high-density point cloud acquisition on complex curved surfaces.

[0022] As a further improvement to this technical solution, the external lifting assembly includes multiple lifting devices 2 at the edge of the worktable. An outer ring is fixed between the output ends of the lifting devices 2. A sliding sleeve 2 is slidably sleeved on the outer side of the outer ring. A first pull rod is hinged to the upper side of the sliding sleeve 2. The first pull rod is rotatably connected to a second pull rod. The second pull rod is rotatably connected to a data acquisition trolley. This can convert vertical motion into smooth pitch swing of the data acquisition trolley along the arc guide rail, realizing rapid and continuous adjustment of the camera angle. This gives the visual acquisition device a wide range of instantaneous angle coverage capabilities, ensuring that the laser spot can be immediately recaptured when it is lost in complex curved surfaces or deep cavity areas, thus seamlessly connecting the scanning cycle.

[0023] As a further improvement to this technical solution, a detection box is fixed on the upper side of the workbench, and a detection port is provided on the front side of the detection box. Both sides of the detection port are slidably connected to light-shielding doors. The light-shielding doors can effectively shield ambient light interference, ensuring that laser measurement is carried out under stable lighting conditions, thus balancing ease of operation and measurement accuracy.

[0024] As a further improvement to this technical solution, the front of the testing box is equipped with a control panel with a built-in programming control module. The front of the control panel is equipped with a display screen for displaying the test results of the earphone shell and multiple command input buttons. The test results are presented in real time through the display screen, and human-machine interaction is realized by combining the command input buttons. This allows the operator to intuitively grasp the measurement status and flexibly control the process without additional equipment, which significantly improves the ease of use of the device and the efficiency of on-site operation.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] 1. In this noise-canceling headphone shell size measurement device based on laser sensor, rapid and comprehensive surface scanning can be achieved through automated motion control and optimized measurement path. The measurement time for a single piece is significantly shortened, meeting the online inspection requirements of the production line. During the scanning process, when the camera loses its spot due to a sudden change in curvature, the system can immediately pause the inner lifting and start the outer lifting. The acquisition carriage is driven to slide along the arc guide rail through the pull rod and sliding sleeve, automatically switching the laser emission angle and acquisition angle between obtuse and acute angles to ensure that the spot always falls stably on the surface being measured. This results in obtaining high-density, seamless, and accurate point cloud data on the entire shell. All subsequent rotation, lifting, and scanning actions are performed around the same reference, eliminating the repetitive positioning error of traditional fixtures and ensuring the consistency and repeatability of 3D reconstruction.

[0027] 2. In this noise-canceling headphone shell size measurement device based on a laser sensor, the first motor drives the swing frame to swing around the X-axis, and the second motor drives the positioning seat to rotate around the Z-axis. The two sets of orthogonal rotations can rotate any surface of the shell to the position to be measured. In conjunction with the 360° circumferential scanning laser emitting device and the real-time switching of the camera's pitch angle, it can realize the measurement of complex curved surfaces without blind spots. It uses sub-pixel spot extraction, coordinate transformation and point cloud registration algorithms to generate a complete three-dimensional model, which solves the problem that it is difficult to completely collect data on the multi-curved surface and deep cavity area of ​​the headphone shell.

[0028] 3. In this noise-canceling headphone shell size measuring device based on a laser sensor, after the headphone shell is manually placed into the positioning seat, multiple shanks are rotated synchronously, and the lead screw moves precisely in and out of the threaded cylinder, driving the pressure feet around to clamp evenly. With the help of vernier calipers, the geometric center of the headphone shell is precisely aligned with the rotation axis of the device. Combined with fully automatic scanning, the error accumulation caused by repeated clamping is eliminated, which can ensure the absolute coordinate accuracy of the final three-dimensional model. Attached Figure Description

[0029] Figure 1 This is an external view of the present invention;

[0030] Figure 2 This is a schematic diagram of the state of the present invention. Figure 1 ;

[0031] Figure 3 Appendix to this invention Figure 2 Enlarged view of the structure at point A in the image;

[0032] Figure 4 Appendix to this invention Figure 2 Enlarged view of the structure at point B in the image;

[0033] Figure 5 This is a schematic diagram of the state of the present invention. Figure 2 ;

[0034] Figure 6 This is a three-dimensional structural diagram of the rotating component in this invention;

[0035] Figure 7 Appendix to this invention Figure 6 Enlarged view of the structure at point C in the image;

[0036] Figure 8 This is a diagram showing the connection structure of the sliding column in this invention;

[0037] Figure 9 This is a diagram showing the connection structure of the camera in this invention;

[0038] Figure 10 This is a diagram of the connection structure of the inner ring in this invention.

[0039] The labels in the diagram represent the following: 1. Workbench; 2. Rotary assembly; 3. Rotating assembly; 4. Inner lifting assembly; 5. Outer lifting assembly; 6. Laser emitting device; 7. Vision acquisition device; 11. Inspection box; 12. Light-shielding door panel; 13. Control panel; 21. Working frame; 22. Swing frame; 23. First motor; 24. Second motor; 25. Positioning seat; 31. Inner ring; 32. Third motor; 33. Gear; 34. Internal gear ring; 41. Enclosing cylinder; 42. Lifter I; 43. Middle ring; 44. 1. Sliding sleeve 1; 45. Side plate; 46. Sliding column; 51. Lifting device 2; 52. Outer ring; 53. Sliding sleeve 2; 54. First pull rod; 55. Second pull rod; 61. Clamping fork; 62. Pin shaft; 63. Strip plate; 64. Laser emitter; 65. Slide groove; 71. Connecting plate; 72. Path guide rail; 73. Acquisition trolley; 74. Camera; 131. Display screen; 132. Command input button; 251. Receiving groove; 252. Threaded cylinder; 253. Lead screw; 254. Presser foot; 255. Column handle. Detailed Implementation

[0040] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] Existing contact measurement methods suffer from drawbacks such as low efficiency of manual operation, decreased accuracy due to wear of the measuring probe, and blind spots in the measurement of complex curved surfaces, while ordinary optical measurement methods are difficult to meet the requirements of high precision.

[0042] Therefore, this invention provides a device for measuring the dimensions of a noise-canceling headphone shell based on a laser sensor, see [link to related document]. Figure 1 As shown, it includes a workbench 1, a detection box 11 is fixed on the upper side of the workbench 1, a detection port is provided on the front side of the detection box 11, and light shielding door panels 12 are slidably connected to both sides of the detection port.

[0043] During operation, after the earphone shell is installed into the positioning seat 25 and clamped, the light-shielding door 12 is manually closed, and the detection box 11 immediately forms a closed dark room environment, effectively shielding the external ambient light interference. During the scanning process, the light-shielding door 12 remains closed to prevent stray light from entering and affecting the image quality of the light spot, thus providing stable optical conditions for laser measurement.

[0044] Further, see Figure 2 , Figure 3 As shown, the central area of ​​the workbench 1 is provided with a rotating assembly 2 for adjusting the display posture of the headphone shell, and a rotating assembly 3 is provided around the rotating assembly 2. A laser emitting device 6 and a vision acquisition device 7 are distributed on both sides of the rotating assembly 3.

[0045] During operation, the laser emitting device 6 and the visual acquisition device 7 can rotate along with the rotating component 3. At the same time, the earphone shell is located at the center of the same field of view of the laser emitting device 6 and the visual acquisition device 7. The display posture of the earphone shell can be adjusted by means of the rotating component 2, thereby realizing all-round scanning.

[0046] Further, see Figure 6 As shown, the laser emitting device 6 includes a clamping fork 61, a pin 62 is rotatably connected between the inner walls of the two sides of the clamping fork 61, a strip plate 63 is rotatably sleeved on the outer side of the pin 62, a laser emitter 64 is fixed at one end of the strip plate 63 facing the earphone shell, and a groove 65 is opened at the other end of the strip plate 63.

[0047] During operation, the sliding column 46 slides along the sliding groove 65 under the drive of the inner lifting component 4, converting the vertical linear motion of the middle ring 43 into the pitch rotation of the strip plate 63 around the pin shaft 62. The laser emitter 64 fixed at the front end of the strip plate 63 changes its emission angle synchronously, realizing continuous and stepless angle adjustment of the laser beam on the surface of the earphone shell from the horizontal area to the steep curved surface, and then to the deep cavity or the inverted part. Throughout the process, the clamping fork 61 remains rigidly connected to the inner ring 31, which can ensure that the rotation center of the laser emitter 64 always coincides with the measurement coordinate system.

[0048] As a preferred option, the laser emitter 64 uses a semiconductor laser with a wavelength of 650nm and an output power of 5mW. The laser beam divergence angle is controlled at 0.5mrad through a beam collimation system to ensure that the spot diameter does not exceed 0.5mm at a distance of 1m. The built-in PZT modulator achieves square wave modulation at a frequency of 10kHz, with a modulation depth of up to 95%.

[0049] Further, see Figure 2 , Figure 3 , Figure 9 As shown, the visual acquisition device 7 includes a connecting plate 71, a path guide rail 72 with an opening facing the earphone shell is fixed on the connecting plate 71, an acquisition trolley 73 that can slide along the outside of the path guide rail 72 is provided, and a camera 74 facing the center of the path guide rail 72 is fixed on the acquisition trolley 73.

[0050] During operation, the control module calculates the desired position of the acquisition trolley 73 synchronously based on the real-time angle of the laser emitter 64 and the current rotation angle of the rotating component 3, and adjusts the sliding speed of the trolley through the closed loop of the external lifting component 5, so that the camera 74 can complete the pitch angle switching within 20ms–70ms, and timely capture the laser spot that may be lost due to abrupt changes in the curved surface or deep cavity obstruction, thereby achieving high-density, seamless 3D point cloud acquisition.

[0051] Preferably, the camera 74 uses a 5-megapixel CMOS sensor with a pixel size of 2.2μm × 2.2μm. Combined with a telecentric optical system with a 0.5X magnification, it ensures image quality free of perspective distortion. The optical system's depth of field is designed to be ±5mm to meet the requirements of curved surface measurement.

[0052] Further, see Figure 2 , Figure 3 , Figure 4 As shown, the rotating assembly 2 includes a work frame 21 fixed on the workbench 1, a swing frame 22 rotatably connected between the inner walls of the two sides of the work frame 21, a first motor 23 fixed on one side of the work frame 21, the output end of the first motor 23 fixedly connected to the swing frame 22, a second motor 24 fixed in the middle of the swing frame 22, and a positioning seat 25 fixed at the output end of the second motor 24.

[0053] During operation, the first motor 23 starts and drives the swing frame 22 to pitch and swing around the X-axis within the working frame 21. The second motor 24 starts and drives the positioning seat 25 to rotate around the Z-axis. The two motors rotate in tandem, enabling the positioning seat 25 to quickly switch between any postures within the spherical coordinate system. The earphone shell moves synchronously with the positioning seat 25, and its test area is adjusted in real time to the common field of view center of the laser emitter 64 and the camera 74.

[0054] Further, see Figure 4 , Figure 10 As shown, a receiving groove 251 is provided on the side of the positioning seat 25 away from the swing frame 22. Multiple threaded cylinders 252 are distributed on the groove wall of the receiving groove 251. A lead screw 253 is threadedly connected to the internal thread of the threaded cylinder 252. One end of the lead screw 253 located in the receiving groove 251 is rotatably connected to a pressure foot 254, and the other end of the lead screw 253 is fixedly connected to a shank 255.

[0055] During operation, the operator places the earphone shell into the receiving slot 251 and then screws each shank 255 sequentially or simultaneously. The lead screw 253 moves precisely within the threaded cylinder 252, driving the pressure feet 254 to move radially synchronously or independently until each pressure foot 254 evenly conforms to the curved surfaces of the earphone shell. Using a vernier caliper, the geometric center of the earphone shell is precisely aligned with the rotation axis of the positioning seat 25, establishing a unified reference in a single clamping operation and completely eliminating repetitive positioning errors. After clamping, the first motor 23 and the second motor 24 drive the positioning seat 25 to rotate orthogonally along two axes, quickly aligning any area of ​​the shell to be measured with the scanning path of the laser emitter 64 and the camera 74.

[0056] Further, see Figure 2 , Figure 3 As shown, an inner lifting component 4 and an outer lifting component 5 are arranged sequentially around the rotating component 3. When the rotating component 3 drives the laser emitting device 6 and the vision acquisition device 7 to rotate, the inner lifting component 4 can synchronously adjust the laser emission angle of the laser emitting device 6, and the outer lifting component 5 can synchronously adjust the vision acquisition angle of the vision acquisition device 7.

[0057] During operation, while the rotating component 3 drives the laser emitting device 6 to perform circumferential scanning, the inner lifting component 4 adjusts the pitch angle of the laser beam in real time and synchronously, so that the laser spot is always accurately projected onto different curved areas of the earphone shell. The outer lifting component 5 adjusts the pitch angle of the camera 74 in real time and synchronously according to the position change or loss of the laser spot, ensuring that it always accurately captures the laser spot, realizing blind-spot-free and discontinuous acquisition of curved surface abrupt changes or deep cavity areas.

[0058] Further, see Figure 5 , Figure 7As shown, the rotating assembly 3 includes an inner ring 31 sleeved on the outside of the working frame 21 and a third motor 32 fixed on the worktable 1. The inner ring 31 has a clamping fork 61 and a connecting plate 71 fixed on both sides respectively. The output end of the third motor 32 is fixed with a gear 33. The outer peripheral wall of the inner ring 31 is provided with an inner toothed ring 34 that meshes with the gear 33.

[0059] During operation, the third motor 32 starts after receiving instructions from the control module, driving the gear 33 to rotate. The gear 33 meshes with the inner tooth ring 34 on the outer peripheral wall of the inner ring 31, causing the inner ring 31 to rotate at a constant speed around the working frame 21. The clamping forks 61 and connecting plates 71 fixed on both sides of the inner ring 31 rotate synchronously, respectively pulling the laser emitting device 6 and the vision acquisition device 7 to perform a 360° circumferential scan. During the rotation, the inner lifting component 4 and the outer lifting component 5 independently adjust the pitch angle of the laser emitting device 64 and the camera 74 according to real-time feedback to ensure high-precision point cloud acquisition of the headphone shell.

[0060] Further, see Figure 7 , Figure 8 As shown, the inner lifting assembly 4 includes an enclosing cylinder 41 fixed on the upper side of the worktable 1. Multiple lifting devices 42 are equidistantly arranged on the enclosing cylinder 41. A middle ring 43 is fixed between the output ends of the lifting devices 42. A sliding sleeve 44 is slidably sleeved on the outer side of the middle ring 43. A side plate 45 is fixed on the upper side of the sliding sleeve 44. A sliding column 46 is fixed on one side of the side plate 45. The sliding column 46 slides with the sliding groove 65.

[0061] During operation, each lifting device 42, under the synchronous command of the control module, pushes the middle ring 43 to move vertically up and down along the axis of the enclosing cylinder 41. The sliding sleeve 44, fixed to the outside of the middle ring 43, moves synchronously and allows the sliding sleeve 44 to maintain low friction sliding in the circumferential direction. The sliding sleeve 44 drives the side plate 45 and the sliding column 46 to move up and down in the vertical direction. The sliding column 46 slides in the groove 65 of the strip plate 63, converting the linear displacement into the continuous change of the pitch angle of the strip plate 63 around the pin shaft 62, thereby accurately and in real time adjusting the laser emission angle of the laser emitter 64. This angle adjustment is synchronized with the circumferential scanning of the rotating component 3, and can be steplessly switched between horizontal detection and curved surface detection to ensure that the light spot is always stably projected onto the surface being measured.

[0062] Further, see Figure 2 , Figure 3 , Figure 9 As shown, the external lifting assembly 5 includes multiple lifting devices 51 at the edge of the workbench 1. An outer ring 52 is fixed between the output ends of the lifting devices 51. A sliding sleeve 53 is slidably sleeved on the outer side of the outer ring 52. A first pull rod 54 is hinged to the upper side of the sliding sleeve 53. A second pull rod 55 is rotatably connected to the first pull rod 54. A collection trolley 73 is rotatably connected to the second pull rod 55.

[0063] During operation, when the system determines that the camera 74 has lost the laser spot due to abrupt changes in curvature or obstruction by the deep cavity, the control module immediately pauses the operation of the inner lifting assembly 4 and simultaneously starts the outer lifting assembly 5. Multiple lifting devices 51 synchronously drive the outer ring 52 to rise and fall along the Z-axis. The sliding sleeve 53 slides on the outer ring 52 and generates circumferential displacement. This displacement is converted into a smooth push and pull of the acquisition carriage 73 along the arc-shaped path guide rail 72 through the hinge linkage of the first pull rod 54 and the second pull rod 55. The acquisition carriage 73 drives the camera 74 to complete the rapid adjustment of the pitch angle (typical range 20°–70°) within 20 ms to 70 ms, so that the angle between the laser emission angle and the visual acquisition angle changes from an obtuse angle to an acute angle (or vice versa), thereby re-capturing the laser spot and resuming continuous scanning without interrupting the cycle, ensuring the integrity and high density of the point cloud data in the deep cavity and inverted areas.

[0064] Further, see Figure 1 , Figure 2 , Figure 3 , Figure 5 , Figure 6 As shown, the front of the detection box 11 is equipped with a control panel 13 with a built-in programming control module. When the angle between the laser emission angle of the laser emitting device 6 and the visual acquisition angle of the visual acquisition device 7 is an obtuse angle, the horizontal position of the headphone shell is detected; when the angle between the laser emission angle of the laser emitting device 6 and the visual acquisition angle of the visual acquisition device 7 is an acute angle, the curved position of the headphone shell is detected. The front of the control panel 13 is equipped with a display screen 131 for displaying the detection results of the headphone shell and multiple command input buttons 132.

[0065] During operation, the operator initiates the measurement process via the command input button 132 on the control panel 13. The built-in programming control module sequentially drives the first motor 23, the second motor 24, the third motor 32, the first lifter 42, and the second lifter 51 according to the preset path and algorithm, realizing the adjustment of the headphone shell posture, circumferential scanning, and the linkage adjustment of the laser and camera angles. The display screen 131 displays the current scanning status, spot capture status, and 3D point cloud reconstruction progress in real time. When the system detects spot loss or abnormality, the control module immediately triggers the compensation mechanism, automatically switches the angle mode between the laser and the camera, and recaptures the spot to ensure measurement continuity. After the measurement is completed, the display screen 131 presents the complete dimensional inspection results, the qualification judgment, and the deviation analysis from the design model.

[0066] In summary, this solution employs a concentric nested structure of three rings: inner ring 31, middle ring 43, and outer ring 52, each driven independently. Inner ring 31 drives the laser emitter 6 and visual acquisition device 7 to rotate 360° circumferentially. Middle ring 43 adjusts the laser angle in real time, and outer ring 52 synchronously adjusts the camera angle 74, constructing a multi-degree-of-freedom scanning space of rotation, laser pitch, and camera pitch. All three share the same rotation axis, and all point cloud data is acquired based on the same coordinate system, enabling the entire surface of the headphone shell to be scanned in a single clamping operation, eliminating repeated positioning errors. When abrupt changes in curvature or a deep cavity inverted area causes spot loss, the system is immediately triggered by the spot loss signal, responding within 50 ms. The internal mode switching is completed. For smooth curved surfaces, the obtuse angle mode (the angle between the laser emitting device 6 and the visual acquisition device 7 is obtuse) is used to ensure depth of field and resolution. For steep curved surfaces or deep cavities, the acute angle mode (the angle between the two devices is acute) is switched. The acquisition carriage 73 is driven to slide along the path guide rail 72 by the outer ring 52 of the outer lifting component 5, the second lifting device 51, the second sliding sleeve 53, the first pull rod 54, and the second pull rod 55. This causes the camera 74 to change its pitch angle instantaneously by 20°–70° to recapture the light spot. The whole process is seamless and does not interrupt the scanning cycle, thus breaking through the limitations of the traditional fixed triangulation angle and realizing the "scan-compensation" closed-loop control to ensure the acquisition of high-density, unbroken point cloud data.

[0067] Working principle:

[0068] First, the earphone shell is manually placed into the receiving slot 251 of the positioning seat 25. The rotating handle 255 causes the lead screw 253 to move back and forth in the threaded cylinder 252, which drives the pressure foot 254 to clamp the shell synchronously. With the help of the vernier caliper, the geometric center and the axis of rotation are precisely aligned to ensure the consistency of the benchmark for subsequent reconstruction.

[0069] Subsequently, the light-shielding door panel 12 is closed, the first motor 23 drives the swing frame 22 to swing around the X-axis in the working frame 21, and the second motor 24 drives the positioning seat 25 to rotate around the Z-axis. The two sets of orthogonal rotations can rotate any surface of the shell to the position to be measured, so as to achieve the complete unfolding of the three-dimensional posture.

[0070] After the earphone shell is in position, the third motor 32 meshes with the inner gear ring 34 through the gear 33, causing the inner ring 31, which is fitted on the outside of the working frame 21, to rotate one position. The laser emitting device 6 and the vision acquisition device 7 then perform a 360° circumferential scan around the shell. At the same time, the lifting device 42 pushes the middle ring 43 to rise and fall, and the sliding column 46 on the sliding sleeve 44 slides in the sliding groove 65 of the strip plate 63, forcing the strip plate 63 to pitch around the pin 62. The angle of the laser emitting device 64 is then precisely changed. The laser emitted by the laser emitting device 6 hits the planar area of ​​the earphone shell to form a light spot. The camera 74 captures the position of the light spot relative to the reference. The curved surface point cloud can be reconstructed by using the trigonometric ranging formula, and the radius of curvature and wall thickness distribution can be calculated.

[0071] When the camera 74 fails to continuously capture the light spot, the first lift 42 pauses, and the second lift 51 synchronously drives the outer ring 52 to rise and fall. Then, through the second sliding sleeve 53, the first pull rod 54, and the second pull rod 55, the acquisition trolley 73 is pulled to slide along the arc path guide rail 72. The camera 74 changes its pitch accordingly, so that the angle between the laser emission angle of the laser emitting device 6 and the visual acquisition angle of the visual acquisition device 7 can be switched between obtuse and acute angles as needed to ensure the continuity of light spot acquisition, thereby enabling precise acquisition of the accurate contour of complex objects such as headphone shells.

[0072] Throughout the scanning process, each frame of the camera 74, the real-time angle of the laser emitter 64, the rotation angle of the rotating component 3, and the height values ​​of each lift are synchronously acquired by the programming control module of the control panel 13. The complete 3D model is generated using sub-pixel spot extraction, coordinate transformation, and point cloud registration algorithms, and compared with the design CAD model. Finally, the qualification judgment and all dimensional results are presented on the display screen 131.

[0073] After the measurement is completed, all motors return to zero. Open the light-shielding door panel 12 and manually loosen the pressure foot 254 to remove or swap the front and back of the earphone shell.

[0074] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A device for measuring the size of a noise-canceling headphone shell based on a laser sensor, comprising a worktable (1), wherein a rotating assembly (2) for adjusting the display posture of the headphone shell is provided in the central area of ​​the worktable (1), characterized in that, The outer periphery of the rotating component (2) is provided with a rotating component (3), an inner lifting component (4) and an outer lifting component (5). A laser emitting device (6) and a visual acquisition device (7) are distributed on both sides of the rotating component (3). When the rotating component (3) drives the laser emitting device (6) and the visual acquisition device (7) to rotate, the inner lifting component (4) can synchronously adjust the laser emitting angle of the laser emitting device (6), and the outer lifting component (5) can synchronously adjust the visual acquisition angle of the visual acquisition device (7). When the angle between the laser emission angle of the laser emitting device (6) and the visual acquisition angle of the visual acquisition device (7) is an obtuse angle, the horizontal position detection of the earphone shell is achieved. When the angle between the laser emission angle of the laser emitting device (6) and the visual acquisition angle of the visual acquisition device (7) is an acute angle, the curved position detection of the earphone shell is realized. The visual acquisition device (7) includes a connecting plate (71), a path guide rail (72) with an opening facing the earphone shell is fixed on the connecting plate (71), an acquisition trolley (73) that can slide along the outside of the path guide rail (72), and a camera (74) facing the center of the path guide rail (72) is fixed on the acquisition trolley (73). The laser emitting device (6) includes a clamping fork (61), a pin (62) is rotatably connected between the inner walls of the two sides of the clamping fork (61), a strip plate (63) is rotatably sleeved on the outer side of the pin (62), a laser emitter (64) is fixed at one end of the strip plate (63) facing the earphone shell, and a groove (65) is opened at the other end of the strip plate (63). The inner lifting assembly (4) includes an enclosing cylinder (41) fixed on the upper side of the workbench (1). Multiple lifting devices (42) are equidistantly arranged on the enclosing cylinder (41). A middle ring (43) is fixed between the output ends of the lifting devices (42). A sliding sleeve (44) is slidably sleeved on the outer side of the middle ring (43). A side plate (45) is fixed on the upper side of the sliding sleeve (44). A sliding column (46) is fixed on one side of the side plate (45). The sliding column (46) slides with the sliding groove (65). The external lifting assembly (5) includes multiple lifting devices (51) at the edge of the workbench (1). An outer ring (52) is fixed between the output ends of the lifting devices (51). A sliding sleeve (53) is slidably sleeved on the outer side of the outer ring (52). A first pull rod (54) is hinged to the upper side of the sliding sleeve (53). A second pull rod (55) is rotatably connected to the first pull rod (54). A collection trolley (73) is rotatably connected to the second pull rod (55).

2. The noise-canceling headphone shell size measuring device based on a laser sensor according to claim 1, characterized in that: The rotating assembly (2) includes a work frame (21) fixed on the workbench (1), a swing frame (22) rotatably connected between the inner walls of the two sides of the work frame (21), a first motor (23) fixed on one side of the work frame (21), the output end of the first motor (23) fixedly connected to the swing frame (22), a second motor (24) fixed in the middle of the swing frame (22), and a positioning seat (25) fixed at the output end of the second motor (24).

3. The noise-canceling headphone shell size measuring device based on a laser sensor according to claim 2, characterized in that: The positioning seat (25) is provided with a receiving groove (251) on the side away from the swing frame (22). Multiple threaded cylinders (252) are distributed on the groove wall of the receiving groove (251). A screw rod (253) is threadedly connected to the inside of the threaded cylinder (252). One end of the screw rod (253) located in the receiving groove (251) is rotatably connected to a pressure foot (254). The other end of the screw rod (253) is fixedly connected to a shank (255).

4. The noise-canceling headphone shell size measuring device based on a laser sensor according to claim 2, characterized in that: The rotating assembly (3) includes an inner ring (31) sleeved on the outside of the working frame (21) and a third motor (32) fixed on the workbench (1). The inner ring (31) is fixed with a clamping fork (61) and a connecting plate (71) on both sides respectively. The output end of the third motor (32) is fixed with a gear (33). The outer peripheral wall of the inner ring (31) is provided with an internal gear ring (34) that meshes with the gear (33).

5. The noise-canceling headphone shell size measuring device based on a laser sensor according to claim 1, characterized in that: A detection box (11) is fixed on the upper side of the workbench (1). A detection port is provided on the front side of the detection box (11), and a light-shielding door plate (12) is slidably connected to both sides of the detection port.

6. The noise-canceling headphone shell size measuring device based on a laser sensor according to claim 5, characterized in that: The front of the testing box (11) is equipped with a control panel (13) with a built-in programming control module. The control panel (13) has a display screen (131) for displaying the test results of the earphone shell and multiple command input buttons (132).

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