Device and method for centering a ship's stern tube using laser tracking

Abstract

This invention provides a device and method for aligning a ship's stern tube using laser tracking, wherein the device includes a rotating component, a telescopic rod, a first base platform, and a second base platform; the telescopic rod includes a fixed rod and a movable rod; the fixed rod is vertically fixed to the rotating component; the first base platform is connected to the fixed rod; the second base platform is connected to the movable rod; the rotating component is hollow tubular. This invention's device and method for aligning a ship's stern tube using laser tracking solves the problems of low measurement accuracy, significant influence of subjective factors on measurement results, and low measurement efficiency in existing technologies.

Description

Technical Field

[0001] This invention relates to the technical field of ship stern tube illumination centering device and method, and particularly to a ship stern tube illumination centering device and method using a laser tracker. Background Technology

[0002] The stern tube is one of the main structural components of a ship's shafting system, primarily serving to support the stern shaft and provide a seal. Before shafting installation, stern tube alignment is required to ensure that the shafting system can accurately pass through the stern tube; this process demands high tolerances.

[0003] A laser tracker is an instrument that uses a laser as a ranging method and is equipped with a reflective target. It also has an angle measuring mechanism that rotates around two axes, forming a complete spherical coordinate measurement system. It can be used to measure stationary targets, track and measure moving targets, or combinations thereof.

[0004] In the prior art, Chinese patent application number 201811630602.X, published on April 2, 2019, describes a centering mechanism and method for a ship's stern tube. This invention designs a centering mechanism including an adjusting ring and an adjusting screw; the adjusting ring is radially provided with an adjusting screw and an adjusting bolt; a centering seat is located at the center of the adjusting ring; the centering seat has a fixed shaft; a conversion shaft is located within the fixed shaft; a target frame is arranged on the conversion shaft; and a dial indicator is mounted on the target frame. In use, the adjusting ring is positioned within the inner wall of the stern tube by adjusting the screw, and the dial indicator pin on the target frame is brought close to the inner wall of the stern tube. The target frame is rotated, and the change in the dial indicator reading is observed. The position of the centering seat is adjusted by adjusting the bolt. Finally, when the difference in dial indicator readings at four positions (upper, lower, left, and right) on the inner wall of the stern tube is less than 0.05 mm after one full rotation of the target frame, the center of the centering seat is determined to be the stern tube center.

[0005] Currently, the above-mentioned centering mechanisms and methods are widely used in the shipbuilding industry, but there are still some shortcomings. These mainly include: (1) low operational accuracy. From the perspective of measurement principle, the dial gauge reading is easily affected by the flatness of the inner wall of the stern tube during the target frame rotation process; (2) the measurement results are greatly affected by personal subjective factors. The dial gauge reading, the fixed position of the adjustment ring, and the accuracy of the adjustment bolt are all closely related to the operator's state and work experience; (3) low measurement efficiency. After knowing the measurement difference at various points on the inner wall of the stern tube, the adjustment of the adjustment bolt depends entirely on the operator's experience. The specific adjustment amount cannot be accurately known. It is necessary to measure again after adjustment and repeat this operation until the stern tube centering is completed. Summary of the Invention

[0006] To address the shortcomings of the existing technology, this invention provides a device and method for centering a ship's stern tube using laser tracking, which can solve the problems of low measurement accuracy, significant influence of subjective factors on measurement results, and low measurement efficiency in the existing technology.

[0007] To achieve the above objectives, the present invention provides a ship stern tube illumination and centering device using a laser tracker, comprising a rotating component, a telescopic rod, a first base platform, and a second base platform; the telescopic rod includes a fixed rod and a movable rod; the fixed rod is vertically fixed to the rotating component; the first base platform is connected to the fixed rod; the second base platform is connected to the movable rod; the rotating component is in the form of a hollow tube.

[0008] Preferably, the telescopic rod further includes a spring; the fixed rod is hollow to form a mounting cavity, the first end of the movable rod is disposed in the mounting cavity, and the mounting cavity limits the first end of the movable rod; the spring is pressed between the first end of the movable rod and the inner wall of the mounting cavity.

[0009] Preferably, the second end of the movable rod is rounded.

[0010] The present invention provides a method for aligning a ship's stern tube using a laser tracker based on the laser tracker-based ship stern tube illumination alignment device described herein, comprising the following steps:

[0011] S1: A stern tube centering mechanism with application number 201811630602.X is arranged at the open end of a stern tube, and the stern tube illumination centering device using a laser tracker is mounted on the fixed shaft of the stern tube centering mechanism via a rotating component to replace the conversion shaft, target frame and dial indicator of the stern tube centering mechanism.

[0012] S2: Magnetically fix a target base to the first base platform and the second base platform respectively; magnetically fix a first reflective target to the target base on the first base platform; and magnetically fix a second reflective target to the target base on the second base platform. Rotate the telescopic rod at a constant speed around the fixed axis to ensure that the target base, the first reflective target, and the second reflective target do not loosen or fall off during the rotation, while the end of the telescopic rod remains in contact with the inner wall of the tailpipe.

[0013] S3: Place a laser tracker in a suitable location and turn it on. Connect the laser tracker to a mobile terminal and confirm that the first and second reflective targets are always within the field of view of the laser tracker throughout the measurement process, and that the mobile terminal can normally receive the measurement data from the laser tracker.

[0014] S4: Adjust the laser emitter head of the laser tracker so that the laser emitted by the laser emitter head is locked onto the first reflective target;

[0015] S5: Slowly rotate the telescopic rod one revolution. During the rotation, ensure that the laser emitted by the laser tracker can follow the movement of the first reflective target. If the laser detaches from the first reflective target midway, the current step needs to be repeated.

[0016] S6: Adjust the laser emitting head of the laser tracker so that the laser emitted by the laser emitting head is locked onto the second reflective target;

[0017] S7: Slowly rotate the telescopic rod one revolution. During the rotation, ensure that the laser emitted by the laser tracker can follow the movement of the second reflective target. If the laser detaches from the second reflective target midway, the current step must be repeated.

[0018] S8: The mobile terminal is operated to fit the two measurement data using a center-finding algorithm and find the distance between the first center of the first circle corresponding to the moving path of the first reflective target and the second center of the second circle corresponding to the moving path of the second reflective target to obtain a corresponding adjustment scheme, and the adjusting screw of the center-finding mechanism of the ship's stern pipe is adjusted according to the adjustment scheme.

[0019] Preferably, the mobile terminal is equipped with the center-finding algorithm.

[0020] Preferably, the center-finding algorithm includes a laser tracker communication module, a target position measurement module, a center calculation module, and an adjustment scheme calculation module;

[0021] The laser tracker communication module is used to connect the mobile terminal and the laser tracker to ensure stable data transmission between the two.

[0022] The target position measurement module is used to control the laser tracker to locate, track and measure the first reflective target and the second reflective target, acquire the target position data of the first reflective target and the second reflective target and store the data;

[0023] The central calculation module is used to analyze and process the target position data and calculate the distance between the first center and the second center;

[0024] The adjustment scheme calculation module is used to analyze the calculation results of the central calculation module and then provide a specific adjustment scheme.

[0025] Because the present invention adopts the above technical solution, it has the following beneficial effects:

[0026] The cooperation between the telescopic rod and the rotating component allows the telescopic rod to contact the inner wall of the tail tube and rotate around a fixed axis via the rotating component. The first and second base platforms connect to the target base. After the telescopic rod rotates, the path of the first base platform is a circle around the fixed axis, and the path of the second base platform is a circle concentric with the tail tube. This provides the hardware basis for calculating the offset between the two circles. The centering device and method used in this invention replace the dial gauge measurement method used in the prior art with laser tracker measurement and are equipped with a dedicated algorithm for processing the measurement results, thus improving measurement accuracy. The precise algorithmic processing of the measurement results greatly avoids the influence of subjective factors on the measurement results; at the same time, it reduces manual adjustment time and improves work efficiency. Attached Figure Description

[0027] Figure 1 This is a side view of a ship stern tube illumination and centering device using a laser tracker, according to an embodiment of the present invention.

[0028] Figure 2 This is a front view of a ship stern tube illumination and centering device using a laser tracker, according to an embodiment of the present invention.

[0029] Figure 3 This is a schematic diagram of the telescopic rod according to an embodiment of the present invention;

[0030] Figure 4 This is a cross-sectional view of the telescopic rod according to an embodiment of the present invention;

[0031] Figure 5 This is a cross-sectional view of the rotating component according to an embodiment of the present invention;

[0032] Figure 6 A front view of a ship stern tube illumination and centering device using a laser tracker, as described in this embodiment of the invention, in a patented tooling.

[0033] Figure 7 A side view of a ship stern tube illumination and centering device using a laser tracker, as described in this embodiment of the invention, in a patented tooling.

[0034] Figure 8 This is a diagram illustrating the usage status of the ship's stern tube illumination and centering device using a laser tracker, according to an embodiment of the present invention.

[0035] Figure 9 This is a schematic diagram illustrating the method for centering a ship's stern tube using laser tracking, based on measurement results, in an embodiment of the present invention, where the center of the circle is calculated by fitting the results.

[0036] Figure 10 This is a flowchart illustrating the method for centering a ship's stern tube using a laser tracker, as described in an embodiment of the present invention. Detailed Implementation

[0037] The following is based on the attached diagram. Figures 1-10 The present invention provides preferred embodiments and describes them in detail to enable a better understanding of the functions and features of the present invention.

[0038] Please see Figures 1-10 An embodiment of the present invention provides a ship stern tube illumination and centering device 1 using a laser tracker, comprising a rotating component 2, a telescopic rod 3, a first base platform 6, and a second base platform 7; the telescopic rod 3 includes a fixed rod 4 and a movable rod 5; the fixed rod 4 is vertically fixed to the rotating component 2; the first base platform 6 is connected to the fixed rod 4; the second base platform 7 is connected to the movable rod 5; the rotating component 2 is in the form of a hollow tube.

[0039] The telescopic rod 3 also includes a spring 8; the fixed rod 4 is hollow to form an installation cavity, the first end of the movable rod 5 is disposed in the installation cavity, and the installation cavity limits the first end of the movable rod 5; the spring 8 is pressed between the first end of the movable rod 5 and the inner wall of the installation cavity.

[0040] The second end of the movable rod 5 is rounded.

[0041] The present invention provides a method for aligning a ship's stern tube using a laser tracker based on the present invention's laser tracker-based ship stern tube illumination device 1, comprising the following steps:

[0042] S1: A ship stern tube centering mechanism 10 with application number 201811630602.X is arranged at the open end of a stern tube 9, and a ship stern tube illumination centering device 1 using a laser tracker is installed on the fixed shaft of the ship stern tube centering mechanism 10 via a rotating component 2 to replace the conversion shaft, target frame and dial indicator of the ship stern tube centering mechanism 10.

[0043] S2: Magnetically fix a target base on the first base platform 6 and the second base platform 7 respectively. Magnetically fix a first reflective target 13 on the target base of the first base platform 6 and a second reflective target 14 on the target base of the second base platform 7. Rotate the telescopic rod 3 at a constant speed around the fixed axis to confirm that during the rotation, the target base, the first reflective target 13, and the second reflective target 14 do not loosen or fall off, and that the end of the telescopic rod 3 always remains in contact with the inner wall of the tail tube 9.

[0044] S3: Place a laser tracker 11 in a suitable position and turn it on. Connect the laser tracker 11 to a mobile terminal 12. Confirm that the first reflective target 13 and the second reflective target 14 are always within the field of view of the laser tracker 11 throughout the measurement process, and that the mobile terminal 12 can receive the measurement data of the laser tracker 11 normally.

[0045] S4: Adjust the laser emitter head of the laser tracker 11 so that the laser emitted by the laser emitter head is locked on the first reflective target 13;

[0046] S5: Slowly rotate the telescopic rod 3 one revolution. During the rotation, ensure that the laser emitted by the laser tracker 11 can follow the movement of the first reflective target 13. If the laser detaches from the first reflective target 13 midway, the current step must be repeated.

[0047] S6: Adjust the laser emitter head of the laser tracker 11 so that the laser emitted by the laser emitter head is locked on the second reflective target 14;

[0048] S7: Slowly rotate the telescopic rod 3 one revolution. During the rotation, ensure that the laser emitted by the laser tracker 11 can follow the movement of the second reflective target 14. If the laser detaches from the second reflective target 14 midway, the current step must be repeated.

[0049] S8: The mobile terminal 12 uses a centering algorithm to fit the two measurement data and find the distance between the first center 15 corresponding to the moving path of the first reflective target 13 and the second center 16 corresponding to the moving path of the second reflective target 14 to obtain the corresponding adjustment scheme. The adjustment screw of the centering mechanism 10 of the ship's stern pipe is adjusted according to the adjustment scheme.

[0050] In this embodiment, the mobile terminal 12 employs a microcontroller and loads a center-finding algorithm. Besides the microcontroller, the mobile terminal 12 of this invention also includes other devices capable of carrying the center-finding algorithm, such as mobile tablets, mobile phones, and laptops.

[0051] The center-finding algorithm includes a laser tracker communication module, a target position measurement module, a center calculation module, and an adjustment scheme calculation module;

[0052] The laser tracker communication module is used to connect the mobile terminal 12 and the laser tracker 11 to ensure stable data transmission between the two.

[0053] The target position measurement module is used to control the laser tracker 11 to locate, track and measure the first reflective target 13 and the second reflective target 14, acquire the target position data of the first reflective target 13 and the second reflective target 14 and store the data;

[0054] The central calculation module is used to analyze and process the target position data and calculate the distance between the first center 15 and the second center 16. In actual use, after the telescopic rod 3 rotates around the fixed axis once, the laser tracker 11 can record the movement path data of the first reflective target. In this invention, the movement path of the first reflective target 13 is a circle with the center of the fixed axis as the center; the movement path of the second reflective target 14 is a circle with the center of the inner wall of the tail tube 9 as the center. The central calculation module can calculate the center of the movement path of the first reflective target 13 and the second reflective target 14, thereby obtaining the distance between the first center 15 and the second center 16.

[0055] The adjustment scheme calculation module is used to analyze the calculation results of the central calculation module and provide a specific adjustment scheme. In actual use, the distance between the first center 15 and the second center 16 is calculated by the central calculation module, and the specific adjustment amount of the adjusting screws in the two directions of the tube centering mechanism 10 of the ship's stern tube is analyzed and given.

[0056] The present invention has been described in detail above with reference to the accompanying drawings and embodiments. Those skilled in the art can make various modifications to the present invention based on the above description. Therefore, certain details in the embodiments should not be construed as limiting the present invention, and the scope of protection of the present invention shall be defined by the appended claims.

Claims

1. A method for aligning a ship's stern tube using a laser tracker, the device (1) comprising a rotating component (2), a telescopic rod (3), a first base platform (6), and a second base platform (7); the telescopic rod (3) comprising a fixed rod (4) and a movable rod (5); the fixed rod (4) being vertically fixed to the rotating component (2); the first base platform (6) being connected to the fixed rod (4); the second base platform (7) being connected to the movable rod (5); the rotating component (2) being hollow; the telescopic rod (3) further comprising a spring (8); the fixed rod (4) being hollow to form an installation cavity, the first end of the movable rod (5) being disposed within the installation cavity, the installation cavity limiting the first end of the movable rod (5); the spring (8) being pressed between the first end of the movable rod (5) and the inner wall of the installation cavity; the second end of the movable rod (5) being rounded; the method comprising the steps: S1: A stern tube centering mechanism (10) is arranged at the open end of a stern tube (9), and the stern tube illumination centering device (1) using a laser tracker is installed on the fixed shaft of the stern tube centering mechanism (10) via a rotating component (2) to replace the conversion shaft, target frame and dial indicator of the stern tube centering mechanism (10). S2: Magnetically fix a target base on the first base platform (6) and the second base platform (7) respectively. Magnetically fix a first reflective target (13) on the target base of the first base platform (6) and a second reflective target (14) on the target base of the second base platform (7). Rotate the telescopic rod (3) at a constant speed around the fixed axis. Confirm that during the rotation, the target base, the first reflective target (13), and the second reflective target (14) do not loosen or fall off. At the same time, the end of the telescopic rod (3) always remains in contact with the inner wall of the tail tube (9). S3: Place a laser tracker (11) in a suitable position and turn it on. Connect the laser tracker (11) to a mobile terminal (12). Confirm that the first reflective target (13) and the second reflective target (14) are always within the field of view of the laser tracker (11) during the entire measurement process, and that the mobile terminal (12) can normally receive the measurement data of the laser tracker (11). S4: Adjust the laser emitting head of the laser tracker (11) so that the laser emitted by the laser emitting head is locked on the first reflective target (13); S5: Slowly rotate the telescopic rod (3) one revolution. During the rotation process, ensure that the laser emitted by the laser tracker (11) can follow the movement of the first reflective target (13). If the laser detaches from the first reflective target (13) in the middle, the current step needs to be repeated. S6: Adjust the laser emitting head of the laser tracker (11) so that the laser emitted by the laser emitting head is locked on the second reflective target (14); S7: Slowly rotate the telescopic rod (3) one revolution. During the rotation process, ensure that the laser emitted by the laser tracker (11) can follow the movement of the second reflective target (14). If the laser detaches from the second reflective target (14) in the middle, the current step needs to be repeated. S8: The mobile terminal (12) is operated to fit the two measurement data using the centering algorithm and find the distance between the first center (15) corresponding to the moving path of the first reflective target (13) and the second center (16) corresponding to the moving path of the second reflective target (14) to obtain the corresponding adjustment scheme, and adjust the adjusting screw of the centering mechanism (10) of the ship's stern pipe according to the adjustment scheme.

2. The method for centering a ship's stern tube using laser tracking as described in claim 1, characterized in that, The mobile terminal (12) is loaded with the center-finding algorithm.

3. The method for centering a ship's stern tube using laser tracking as described in claim 2, characterized in that, The center-finding algorithm includes a laser tracker communication module, a target position measurement module, a center calculation module, and an adjustment scheme calculation module; The laser tracker communication module is used to connect the mobile terminal (12) and the laser tracker (11) to ensure stable data transmission between the two. The target position measurement module is used to control the laser tracker (11) to locate, track and measure the first reflective target (13) and the second reflective target (14), and to obtain and store the target position data of the first reflective target (13) and the second reflective target (14). The central calculation module is used to analyze and process the target position data and calculate the distance between the first center (15) and the second center (16); The adjustment scheme calculation module is used to analyze the calculation results of the central calculation module and then provide a specific adjustment scheme.

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