Ship propulsion shafting deformation detection system and detection method

Abstract

The invention provides a ship propulsion shafting deformation optical detection system and detection method. The system comprises a laser; the target piece is arranged at the thrust bearing and used for receiving the laser datum line and forming a first light spot; the at least one measuring assembly is correspondingly arranged at the position of the middle bearing, each measuring assembly comprises state switchable dimming glass and a camera used for collecting images, and the dimming glass has an atomization state capable of enabling the laser to form a second light spot on the surface of the dimming glass; the controller is used for controlling the dimming glass to be sequentially switched to an atomized state and triggering the corresponding cameras to carry out image acquisition; and the processor is used for determining the position change of the second light spot according to the image acquired by the camera and correcting the position change of the second light spot according to the position change of the first light spot on the target piece so as to obtain deformation data of the intermediate bearing. According to the technical scheme, ship motion interference can be effectively resisted, synchronous measurement of multi-dimensional deformation is realized, and drift of a measurement reference can be automatically corrected, so that high-precision real-time monitoring is completed.

Description

Technical Field

[0001] This application belongs to the field of marine engineering technology, and in particular relates to a deformation detection system and method for ship propulsion shafting. Background Technology

[0002] The propulsion shafting system is the core power component that transmits main engine power to the propeller and propulsion force to the hull. Large ocean-going vessels typically undergo shafting alignment, installation, and commissioning during the launching and mooring phase. This process requires determining the main engine position and connecting and commissioning corresponding piping equipment, significantly extending the overall mooring period. By moving shafting alignment to the dry dock phase, and simultaneously advancing the installation and commissioning of much of the related equipment, the shipbuilding cycle can be significantly shortened. However, changes in the hull's condition during launching can cause deformation of the shafting structure, affecting its operational safety. Therefore, it is necessary to monitor shafting deformation during launching and obtain data on this deformation.

[0003] According to the shipbuilding plan, the launching of a ship involves a series of processes, including lifting and shifting, transshipment, sinking and floating, berthing, ballast tank strength testing, containment construction, and pre-dock loading adjustments. Afterward, the ship is moved into the dock and mounted on the main deck for shaft alignment under illumination. To effectively monitor hull structural deformation and ensure that its data meets the technical requirements for shaft alignment under illumination, and to achieve full-process deformation monitoring, it is essential to adjust construction measures and control precision promptly based on data changes. Furthermore, data collection and analysis will accumulate crucial experience for implementing shaft alignment and forward movement techniques in subsequent construction projects. Therefore, providing a technical solution capable of real-time monitoring of propulsion shaft deformation is necessary. Summary of the Invention

[0004] In view of the shortcomings of the prior art described above, the purpose of this application is to provide a ship propulsion shaft deformation detection system and detection method. The system and method can overcome the interference of ship motion, realize high-precision real-time monitoring without manual intervention, measure multi-dimensional deformation simultaneously, and automatically correct measurement reference drift.

[0005] To achieve the above and other related objectives, in a first aspect, this application provides an optical detection system for ship propulsion shaft deformation, comprising:

[0006] A laser used to generate a laser reference line;

[0007] A target component, disposed at the thrust bearing, is used to receive the laser reference line and form a first light spot;

[0008] At least one measuring component is correspondingly disposed at the intermediate bearing, each measuring component including a state-switchable dimming glass and a camera for acquiring images, the dimming glass having a frosted state that enables a laser to form a second spot on its surface;

[0009] The controller is used to control each of the dimming glass to switch to the fogging state in sequence and trigger the corresponding camera to acquire images;

[0010] The processor is used to determine the positional change of the second light spot based on the image acquired by the camera, and to correct the positional change of the second light spot based on the positional change of the first light spot on the target, so as to obtain the deformation data of the intermediate bearing. The above technical solution establishes a stable spatial reference line using laser light and utilizes the state switching of the electrically controlled dimming glass to achieve measurement of different points on the same laser line, fundamentally avoiding interference from multiple light spots. Simultaneously, the system monitors the spatial drift of the reference line itself through the target and uniformly corrects all measurement point data, thereby ensuring that the measurement results, even in unstable environments such as ship motion, reflect the true deformation of the bearing, rather than the illusion caused by the swaying of the reference line.

[0011] Secondly, a method for detecting deformation of a ship's propulsion shafting system is provided. This method uses the system provided by the above-mentioned technical solution and includes the following steps:

[0012] S1: Sequentially control the dimming glass located above each intermediate bearing to switch to the atomization state;

[0013] S2: When any of the dimming glass is atomized, acquire the laser spot image on the surface of the dimming glass, and acquire the laser spot image on the surface of the target component set at the thrust bearing;

[0014] S3: Correct the position change of the light spot on the surface of the dimming glass based on the position change of the light spot on the surface of the target component;

[0015] S4: Determine the deformation of the corresponding intermediate bearing based on the corrected change in the position of the light spot.

[0016] Compared with the prior art, the technical solution provided in this application has the following beneficial effects:

[0017] The ship propulsion shaft deformation detection system provided in this application can withstand the complex environmental interference during shipbuilding and launching. It innovatively proposes establishing a laser line as a measurement baseline between the stern bearing and the thrust bearing. Utilizing the characteristic of dimming glass to form a clear light spot after atomization, and employing camera imaging and image processing, it achieves high measurement accuracy. By establishing a frame coordinate system, the measurement accuracy is ensured to be unaffected by camera position and orientation errors. This technical solution not only significantly improves the accuracy and efficiency of shaft deformation detection but also provides effective support for the implementation of advanced processes such as shaft alignment and forward shifting in shipbuilding. It also has significant engineering practical value and economic benefits in shortening shipbuilding cycles, reducing construction costs, and ensuring the long-term safe operation of ships. Attached Figure Description

[0018] Figure 1 A flowchart of the ship propulsion shaft deformation detection method provided in this application.

[0019] Figure 2 This is a diagram illustrating the camera mounting method.

[0020] Figure 3 This is a schematic diagram of the power supply and camera control method.

[0021] Figure 4 Let be the coordinate system of the dimming glass frame. Detailed Implementation

[0022] Currently, the methods used for detecting deformation of propulsion shafting in large ships include total station measurement and static leveling.

[0023] Total Station Measurement Method: This method involves using a total station to detect shaft deformation. It requires setting up a total station near the shaft line and measuring the linear deviation of each intermediate bearing relative to the stern and thrust bearings. Due to potential obstructions from other structural components near the shaft, multiple control points need to be established within the vicinity. During testing, the total station needs to be set up at each of these control points, measuring the nearest visible marker, and finally calculating the deformation displacement of each shaft. This method is labor-intensive and time-consuming, especially after the ship has been launched, as the instability of the hull itself can significantly affect measurement accuracy.

[0024] Static leveling method: This method for detecting shaft deformation requires installing pressure sensors on the intermediate bearing, stern bearing, and thrust bearing. These sensors are connected by a connecting pipe filled with a special liquid. By measuring the pressure difference exerted by the liquid on the sensors, the vertical displacement of the intermediate bearing relative to the stern and thrust bearings is determined. However, once the ship is in the water, its instability makes the accuracy of static leveling insufficient for the required shaft measurement accuracy. Furthermore, static leveling cannot determine the lateral deformation displacement of the shaft system.

[0025] When shaft alignment work is moved to the dry dock stage, shaft deformation needs to be monitored at various stages during hull transfer, launching, and mooring. Therefore, existing technologies, whether using total stations or static levels, require the instruments and sensors to be in a stable state. In cases of hull instability, the accuracy of shaft measurement cannot be guaranteed. Furthermore, static levels can only measure vertical deformation, not horizontal deformation, thus failing to fully meet the requirement of simultaneously measuring both vertical and lateral shaft deformation.

[0026] Based on the background technology and the aforementioned deficiencies of the prior art, this application provides an optical detection system and method for ship propulsion shaft deformation, which solves the problem of measuring the vertical and lateral relative deformation between the intermediate bearing, stern bearing and thrust bearing in the propulsion shaft in real time before the propulsion shaft is installed. No manual operation is required during the measurement, and its measurement accuracy is not affected by factors such as hull movement and attitude changes.

[0027] In a first aspect, this application provides an optical detection system for ship propulsion shaft deformation, comprising:

[0028] A laser used to generate a laser reference line;

[0029] A target component, disposed at the thrust bearing, is used to receive the laser reference line and form a first light spot;

[0030] At least one measuring component is correspondingly disposed at the intermediate bearing, each measuring component including a state-switchable dimming glass and a camera for acquiring images, the dimming glass having a frosted state that enables a laser to form a second spot on its surface;

[0031] The controller is used to control each of the dimming glass to switch to the fogging state in sequence and trigger the corresponding camera to acquire images;

[0032] The processor is used to determine the positional change of the second light spot based on the image acquired by the camera, and to correct the positional change of the second light spot based on the positional change of the first light spot on the target, so as to obtain the deformation data of the intermediate bearing. The above technical solution establishes a stable spatial reference line using laser light and utilizes the state switching of the electrically controlled dimming glass to achieve measurement of different points on the same laser line, fundamentally avoiding interference from multiple light spots. Simultaneously, the system monitors the spatial drift of the reference line itself through the target and uniformly corrects all measurement point data, thereby ensuring that the measurement results, even in unstable environments such as ship motion, reflect the true deformation of the bearing, rather than the illusion caused by the swaying of the reference line.

[0033] In some embodiments, the dimming glass is in a frosted state when not powered and in a transparent state when powered. The controller switches the state of the dimming glass by controlling the power-on state, avoiding problems such as wear, jamming, and positioning errors caused by using mechanical baffles, and improving the long-term reliability and response speed of the system.

[0034] In some embodiments, the dimming glass and / or the target are provided with multiple optical reference marks. The processor is used to convert the pixel coordinates of the light spot into physical coordinates based on the position of the optical reference marks in the image. This effectively avoids measurement errors introduced by changes in the camera's own pose.

[0035] In some embodiments, the camera is mounted to the side front of the corresponding dimming glass, with its principal optical axis forming an angle greater than 30 degrees with the plane of the dimming glass. This design can completely cover the target surface of the dimming glass, ensure that the perspective distortion of the image is within a manageable range, and at the same time, the side front mounting avoids interference with the laser path.

[0036] In some implementations, the processor corrects the initial displacement measurement ΔQi of the i-th intermediate bearing to obtain the true deformation ΔQi':

[0037] ΔQi' = ΔQi - (di / D) * ΔP;

[0038] Where di is the distance from the laser to the intermediate bearing, D is the distance from the laser to the target, and ΔP is the displacement of the laser spot on the target. By distributing and subtracting the total drift monitored by the target according to the distance from each measurement point to the laser source, online real-time calibration of the measurement results is achieved.

[0039] In some implementations, the controller sequentially switches the state of each dimming glass at preset time intervals and triggers the corresponding camera to take pictures during the switching intervals. Through the cyclic control of preset time intervals, the system can continuously and orderly poll and monitor all measuring points without manual intervention, achieving automated continuous operation and meeting the needs of long-term monitoring.

[0040] In some embodiments, the processor is further configured to continuously capture multiple images from the same dimming glass-triggered camera and select images with stable light spot positions for calculation. By continuously capturing multiple images of the same state and selecting stable results, abnormal data points caused by instantaneous hull shaking, occasional fluctuations in illumination, or electronic noise can be effectively filtered out, improving the confidence of single measurement results and overall data quality.

[0041] In some implementations, the state switching response time of the dimming glass is less than 50 milliseconds to ensure high measurement efficiency of the system.

[0042] Secondly, a method for detecting deformation of a ship's propulsion shafting system is provided. This method uses the system provided by the above-mentioned technical solution and includes the following steps:

[0043] S1: Sequentially control the dimming glass located above each intermediate bearing to switch to the atomization state;

[0044] S2: When any of the dimming glass is atomized, acquire the laser spot image on the surface of the dimming glass, and acquire the laser spot image on the surface of the target component set at the thrust bearing;

[0045] S3: Correct the position change of the light spot on the surface of the dimming glass based on the position change of the light spot on the surface of the target component;

[0046] S4: Determine the deformation of the corresponding intermediate bearing based on the corrected change in the position of the light spot.

[0047] In some implementations, the method is used for automatic and continuous monitoring of shafting deformation during launching or mooring of a vessel.

[0048] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. This application can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application.

[0049] It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of this application. Therefore, the illustrations only show the components related to this application and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the shape, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0050] See Figures 1 to 4In the ship propulsion shaft deformation detection system provided in this embodiment, a laser is installed above the stern bearing, and a flat white plastic plate is installed above the thrust bearing. The light projected by the laser forms a measurement reference line, which passes through the tops of each intermediate bearing. Smart dimming glass is installed above each intermediate bearing, and the power switch of the smart dimming glass installed on each intermediate bearing can be controlled accordingly. When the power to the dimming glass is off, the glass is in a frosted state, and light forms a light spot when projected onto the dimming glass. Conversely, when the power to the dimming glass is on, the glass is in a transparent state, and light can pass through the dimming glass to reach the smart dimming glass installed above the next intermediate bearing. A high-precision industrial camera is installed below and in front of each dimming glass to capture the position and changes of the light spot on the frosted glass, thereby determining the vertical and horizontal displacement deformation of the intermediate bearing.

[0051] The detection system provided in this embodiment includes hardware and software, specifically: a laser emitter, a dimming glass, a white plastic plate, a camera, a power supply and camera controller, and related software. A specific example of each component is provided below for detailed explanation.

[0052] Laser emitter: 1 unit, effective working distance greater than 120m, spot diameter at 60m not greater than 4mm, power supply voltage 3.7V, maximum optical power 15mW.

[0053] Smart dimming glass: Measuring 250*250mm, one smart dimming glass is installed on each intermediate bearing. When the power is off, the light transmittance of the dimming glass is less than 5%, resembling frosted glass; when powered on, the light transmittance is greater than 75%, approaching transparency. When a laser beam is projected onto the frosted dimming glass, a distinct light spot will be produced; conversely, when the dimming glass is transparent, no distinct light spot will be produced, and the light passes through the dimming glass to the next dimming glass on the intermediate bearing. The power-on response time of the dimming glass is less than 45ms. By controlling the power supply of each dimming glass on the intermediate bearing in this manner, making them successively transparent or frosted, a light spot can be formed on each dimming glass in a short time. A small spherical light source is installed at each corner of the dimming glass frame, and the frame coordinate system of the dimming glass is established using these four light sources. The spherical light sources use light of the same wavelength as the laser, facilitating the use of filters by the camera.

[0054] White plastic plate: The white plastic plate is installed above the thrust bearing. The white plastic plate has the same appearance and size as the dimming glass and can also display the light spot projected by the laser. The same spherical light source is also installed at the four corner points to establish the same frame coordinate system as the dimming glass.

[0055] camera: Figure 2This diagram illustrates the actual camera and its installation method. An area-array industrial camera is mounted in front of and below each dimming glass panel. The camera's field of view is approximately 200*180mm (height and width), close to the size of the dimming glass panel. A camera with a resolution of at least 4000×3600 pixels, a pixel accuracy of 0.05mm / pixel, and a soft-trigger latency of less than 1ms is used. The camera, dimming glass, and white plastic panel are installed independently. The dimming glass, plastic panel, intermediate bearing, and thrust shaft are fixedly mounted. The camera can be mounted on an independent bracket, 500mm away from the dimming glass and plastic panel, and slightly below the effective reflective surface of the dimming glass and plastic panel.

[0056] Power supply and camera controller: Figure 3 This diagram illustrates the power supply and camera control method. The controller can be an industrial microcomputer that connects to the power supply and camera controller via specially programmed software, controlling the power supply to each dimming glass and the camera's shooting action. At 0.2-second intervals, the power supply to the dimming glass closest to the light source is sequentially switched on and off, simultaneously triggering continuous shooting by the camera in front of the unpowered dimming glass at the very front.

[0057] Software: The main functions of the software include continuously taking multiple shots and collecting light spots on the current fogged dimming glass, automatically removing unclear light spot image data, comparing the light spot position data collected multiple times, stopping shooting when three sets of position data are consistent, and notifying the system to switch to collecting fogging and light spot position data for the next dimming glass.

[0058] The working principle of the problem of changing relative positions between the camera and the dimming glass is as follows:

[0059] Since both the dimming glass and the plastic plate are fixedly mounted on the bearing, their positional changes relative to the bearing are minimal and negligible; however, the camera is independently mounted. Nevertheless, due to temperature variations, environmental vibrations, and the elasticity of the mounting bracket, the camera's directional changes may affect the imaging position of the light spot in the image. Therefore, a frame coordinate system needs to be established on the dimming glass. During image processing, the light spot position is reconstructed within this frame coordinate system to obtain the light spot's position within the dimming glass's frame coordinate system. This ensures that, while maintaining stability of the dimming glass relative to the corresponding bearing, the change in the light spot's position on the dimming glass reflects the bearing's deformation and displacement.

[0060] See Figure 4A coordinate system O-XY is established on the dimming glass frame. The calibrated positions (x1, y1) to (x4, y4) of the spherical light sources (K1~K4) at the four corner points are obtained in the frame coordinate system beforehand. During actual measurement, the image coordinates (u1, v1) to (u4, v4) of the spherical light sources are acquired through real-time image capture, along with the image coordinates (ut, vt) of the captured light spot. Generally, the relationship (or relative positional relationship) between the captured object and the image shape involves positional offset, rotational offset, and axial linear deformation, the parameters of which can be denoted as... These parameters allow us to establish the relationship between the frame coordinate system and the image coordinate system at the time of shooting:

[0061]

[0062] With four spherical light sources, the above formulas have four pairs (eight in total) and can solve for five parameters.

[0063] After obtaining the transformation parameters between the two coordinate systems, the coordinates (xt, yt) in the frame coordinate system can be calculated based on the coordinates (ut, vt) of the light spot in the camera coordinate system, i.e.:

[0064]

[0065] In the above calculations, the camera position and shooting direction will not affect the result of the light spot in the frame coordinate system. However, in actual calculations, in order to ensure the accuracy of parameter solution, there are certain requirements for the camera's shooting angle, that is, the angle between the camera's main axis and the surface being photographed should be greater than 60°.

[0066] The above description also applies to the handling of the coordinate system of the plastic board frame.

[0067] The method for correcting the spatial direction of a laser line is as follows:

[0068] Due to factors such as changes in ambient temperature, vibration, and the stability of the laser installation, the direction of the laser beam projected from the laser may also change in the air, causing measurement errors in the deformation displacement of the intermediate bearings. This error can be corrected by measuring the laser spot position on the plastic plate mounted on the thrust bearing. The change in the position of the laser spot on the plastic plate mounted on the thrust bearing reflects the change in the aerial measurement baseline, requiring correction of the measurement results for each intermediate bearing to offset the influence of the baseline deviation.

[0069] The specific method is to distribute the deviation value according to the distance from the light source, taking the X-axis direction as an example:

[0070]

[0071] Where D is the distance between the light source (stern bearing) and the dimming glass of the thrust bearing. The distance between the light source and the dimming glass of the intermediate bearing. For the displacement of the light spot in the dimming glass of the thrust bearing, To and The correction amount for the measurement results of the corresponding intermediate bearing dimming glass. The calculation method for the correction in the Y-axis direction is the same as that in the X-axis direction.

[0072] In summary, the technical solution provided in this application mainly includes: establishing a laser line as the measurement reference line, correcting the spatial direction of the laser line, using a dimming glass to form a light spot during atomization, establishing a measurement coordinate system on the dimming glass, and transforming the position of the light spot on the image to the measurement coordinate system so that it is not affected by camera position and orientation errors. This technical solution uses a laser line as the reference line for shaft deformation measurement. The direction of the light beam is not affected by the ship's motion. After spatial correction, the direction of the light beam has extremely high spatial stability, meeting the requirements of high-precision measurement for the measurement reference. An industrial camera is used for close-range detection of the light spot displacement, achieving a measurement accuracy of 0.1~0.2mm. The system has a high degree of automation, requires no manual intervention, and can automatically detect shaft deformation for extended periods.

[0073] Therefore, the technical solution provided in this application has high industrial application value because it effectively overcomes the various shortcomings of the prior art.

[0074] The above embodiments are merely illustrative of the principles and effects of this application and are not intended to limit this application. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this application. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this application should still be covered by the claims of this application.

Claims

1. An optical detection system for ship propulsion shaft deformation, characterized in that, include: Laser, used to generate laser reference lines; A target component, disposed at the thrust bearing, is used to receive the laser reference line and form a first light spot; At least one measuring component is correspondingly disposed at each intermediate bearing. Each measuring component includes a switchable dimming glass and a camera for acquiring images. The dimming glass has a frosted state that allows a laser to form a second spot on its surface. The controller is used to control each of the dimming glass to switch to the fogging state in sequence and trigger the corresponding camera to acquire images; The processor is configured to determine the positional change of the second light spot based on the image captured by the camera, and to correct the positional change of the second light spot based on the positional change of the first light spot on the target component, so as to obtain the deformation data of the intermediate bearing.

2. The optical detection system for ship propulsion shaft deformation according to claim 1, characterized in that, The dimming glass is in a frosted state when not powered and in a transparent state when powered. The controller switches the state of the dimming glass by controlling the power-on state.

3. The optical detection system for ship propulsion shaft deformation according to claim 1, characterized in that, The dimming glass and / or the target are provided with a plurality of optical reference marks, and the processor is used to convert the pixel coordinates of the light spot into physical coordinates based on the position of the optical reference marks in the image.

4. The optical detection system for ship propulsion shaft deformation according to claim 1, characterized in that, The camera is mounted on the side front of the corresponding dimming glass, and the angle between its main optical axis and the plane of the dimming glass is greater than 30 degrees.

5. The optical detection system for ship propulsion shaft deformation according to claim 1, characterized in that, The processor corrects the initial displacement measurement value ΔQi of the i-th intermediate bearing to obtain the true deformation ΔQi': ΔQi' = ΔQi - (di / D) * ΔP; Where di is the distance from the laser to the intermediate bearing, D is the distance from the laser to the target, and ΔP is the displacement of the laser spot on the target.

6. The optical detection system for ship propulsion shaft deformation according to claim 1, characterized in that, The controller sequentially switches the state of each dimming glass at preset time intervals and triggers the corresponding camera to take pictures during the switching intervals.

7. The optical detection system for ship propulsion shaft deformation according to claim 1, characterized in that, The processor is also configured to continuously capture multiple images from the same dimming glass-triggered camera and select images with stable light spot positions for calculation.

8. The optical detection system for ship propulsion shaft deformation according to claim 1, characterized in that, The state switching response time of the dimming glass is less than 50 milliseconds.

9. A method for detecting deformation of a ship's propulsion shafting, employing the system as described in any one of claims 1 to 8, characterized in that, Includes the following steps: S1: Sequentially control the dimming glass located above each intermediate bearing to switch to the atomization state; S2: When a certain dimming glass is atomized, the laser spot image on the surface of the dimming glass and the laser spot image on the surface of the target set at the thrust bearing are acquired simultaneously. S3: Correct the position change of the light spot on the surface of the dimming glass based on the position change of the light spot on the surface of the target component; S4: Determine the deformation of the corresponding intermediate bearing based on the corrected change in the position of the light spot.

10. The method for detecting deformation of a ship propulsion shafting system according to claim 9, characterized in that, This method is used for automatic and continuous monitoring of shaft deformation during launching or mooring of ships.

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