Ship parallel wet transport hose curvature radius distribution inversion method

Abstract

The present application relates to the technical field of deep-sea mining, and specifically discloses a ship parallel approach wet transportation hose curvature radius distribution inversion method, comprising: obtaining multiple synchronous ranging echo of the hose span area through a ranging array arranged at the deck edge of two ships, and combining six-degree-of-freedom pose data of the MRU of the two ships to complete time synchronization and platform motion compensation, thereby obtaining effective ranging beams; performing beam line back-projection and fusion inversion on the effective ranging beams in the motion-compensated parallel approach reference coordinate system, thereby extracting a hose center line discrete point column; based on the hose center line discrete point column, using a discrete curvature formula to calculate the curvature radius distribution and obtain the minimum radius; introducing the minimum radius into the sea state release amount and the look-ahead time window, thereby obtaining the predicted minimum radius. The present application significantly reduces the false alarm and missed alarm conditions in the hose bending monitoring and prediction in the old ship parallel approach wet transportation, and supports hose bending monitoring and prediction under high sea conditions.

Description

Technical Field

[0001] This invention relates to the field of deep-sea mining technology, and in particular to a method for inverting the radius of curvature distribution of wet transport hoses used by ships. Background Technology

[0002] Currently, in wet transport operations alongside ships, the mainstream approach for inverting the curvature radius distribution of hoses mostly employs a single-sided camera or manual inspection, supplemented by local strain, tension, and tilt sensors. Fixed thresholds are set for a few specific hotspot locations, and alarms or transport are only triggered when the observed measurements exceed the defined range. This method generally suffers from the following shortcomings: First, the observed values ​​are local point values, which are difficult to characterize the curvature radius distribution of the entire hose, resulting in a high risk of false alarms and missed alarms. Secondly, the two ships move significantly relative to each other in six degrees of freedom during operation, and the fixed threshold is difficult to adapt to the bending evolution caused by changes in sea state.

[0003] Therefore, there is an urgent need for systematic optimization through digital technology to make monitoring and prediction more accurate and adaptable to more complex sea conditions. Based on this, a method for inverting the curvature radius distribution of ship-to-ship wet transport hoses based on the fusion of ranging array and MRU six degrees of freedom is proposed. Summary of the Invention

[0004] The purpose of this invention is to solve the technical problems existing in the prior art and to provide a method for inverting the curvature radius distribution of ship-to-ship wet transport hoses based on the fusion of ranging array and MRU six degrees of freedom.

[0005] To achieve the above objectives, the present invention provides a method for inverting the radius of curvature distribution of wet transport hoses used in parallel berthing of ships, comprising the following steps: S1. Obtain multiple synchronous ranging echoes in the hose crossing area through the ranging array arranged at the edge of the decks of the two ships, and combine them with the six-degree-of-freedom pose data of the MRU of the two ships to complete time synchronization and platform motion compensation, and obtain an effective ranging beam. S2. Perform beamline back projection and fusion inversion on the effective ranging beam in the motion-compensated parallel reference coordinate system to extract the discrete point series of the hose centerline. S3. Based on the discrete point array of the hose centerline, the curvature radius distribution is calculated using the discrete curvature formula, and the minimum radius is obtained; S4. Incorporate the minimum radius into the sea state amplification and look-ahead time window to obtain the predicted minimum radius.

[0006] Preferably, step S1 specifically comprises: The six-degree-of-freedom pose data includes sway, roll, heave, pitch, pitch and yaw motion data; S111. Arrange a ranging array on both sides of the deck edge of the hose crossing area between the two ships, and establish and attach a reference coordinate system. S112. Acquire ranging echo and echo quality factor, and determine whether the ranging echo validity is acceptable; if yes, proceed to step S13; if no, remove invalid data and check the ranging unit status, and then reacquire ranging echo and echo quality factor. The echo quality factor is a dimensionless index used to evaluate the reliability of single-beam ranging echoes, which is obtained by normalizing the ranging matrix echo intensity, confidence level, and signal-to-noise ratio. S121. Motion reference units (MRUs) are arranged on the decks of both ships; S122. Collect the six-degree-of-freedom pose data of the two ships, and determine whether the motion of the two ships is stable based on the pose data. If yes, proceed to step S13; otherwise, stop the machine immediately. S13. Based on the six-degree-of-freedom pose data of the two ships, the ranging echoes are uniformly mapped to the reference coordinate system and the effective ranging beam is output.

[0007] Preferably, the ranging array uses laser ranging, millimeter-wave ranging, or ultrasonic ranging units; each vessel is equipped with 8-16 ranging units, evenly spaced along the direction of the hose crossing, with a spacing of 0.3-0.8m; the beam pitch angle is 10°-35°, and the left and right coverage angles are not less than twice the lateral swing range of the hose; the working distance is 4-25m; and the sampling frequency is 50-200Hz. The sampling frequency of the MRU on both ships is the same as or an integer multiple of the sampling frequency of the ranging array.

[0008] Preferably, the aforementioned berthing reference coordinate system refers to a common coordinate system that uniformly describes the spatial shape and relative motion relationship of the deck equipment and hoses of the two ships during berthing operations. Specifically, it is established using a fixed reference point on one ship's deck, with the x-axis pointing towards the bow, the y-axis pointing towards the starboard side, and the z-axis vertically upward. The extrinsic parameter calibration of the ranging array is completed using a fixed target or calibration rod to obtain data for each ranging unit. The zero-bias drift is then verified using a static segment, wherein the first... The installation points of each ranging unit are The unit vector of the beamline direction is Zero bias is The coordinates of the equipment on the other ship, the coordinates of the ranging array, and the point cloud of the hose are uniformly registered into this coordinate system through rigid body transformation. The specific steps for determining the validity of the ranging echo are as follows: Preset the data range, distance jump threshold, and echo quality factor threshold for the ranging echo, and then acquire the ranging echo. and echo quality factor ;when Less than the preset echo quality factor threshold or Not within the preset data range or If the distance jump exceeds a preset threshold, the ranging echo is considered invalid.

[0009] Preferably, step S2 specifically comprises: S21. For any valid ranging beam, construct the beamline back projection constraint points. The expression is: ; in, For rigid body transformations corresponding to hull A or B. For the first The installation point of each ranging unit, For the first The unit vector of the beamline direction of each ranging unit. For the first Zero bias of each ranging unit; The constraint point set is obtained by summing all the constraint points. ; S22. Invert the discrete point sequence of the hose centerline based on the constraint point set and perform spline fitting; Discretize the centerline of the hose into N nodes. , The nominal arc length spacing is The nominal arc length spacing refers to the pre-set target arc length interval between adjacent discrete nodes along the curve direction of the hose centerline, which is taken as 0.2-0.8m; based on the constraint point set Invert the centerline of the hose and construct the ranging inversion objective function. : ; in, For point The shortest distance to the centerline broken line; The robust weights are obtained by mapping the echo quality factor. For smoothing regularization coefficients; The quasi-inextensible constraint coefficient; Let the set of discrete nodes along the centerline of the hose be: ; Let its initial guess be The weighted Gauss-Newton iterative method is used to evaluate the objective function. Minimize by gradually updating node positions. The time interval is obtained as the number of cycles decreases monotonically or tends to converge. The optimal discrete point sequence of the centerline: ; in, For at any time By minimizing the objective function The optimal centerline discrete point sequence is obtained; Take the previous moment optimal solution As an initial guess at the current moment This enables real-time continuous tracking of the hose centerline. The inverted point sequence is then spline-fitted. S23. Define the fitting residuals and determine whether the spline fitting effect is acceptable based on the fitting residuals; if yes, output the discrete point sequence of the hose centerline; if no, adjust the smoothing regularization coefficient in the ranging inversion objective function. Quasi-inextensible constraint coefficient Or determine the spline tension parameter, and then proceed to step S22; The conditions for acceptable spline fitting are that the centerline is continuous and the residuals are stable. The fitting residual is: .

[0010] Preferably, step S3 specifically includes: S31. Based on the discrete point sequence of the hose centerline, the radius of curvature distribution is calculated using the five-point discrete curvature formula, specifically: For the Centerline node Take its four adjacent points to obtain , , , , Define a five-point first-order difference vector. With the five-point second-order difference vector for: ; ; Define a five-point discrete curvature estimator for: ; Define the radius of curvature : ; in, This is the lower limit threshold for curvature; S32, Obtain the minimum radius: .

[0011] Preferably, step S4 specifically comprises: The look-ahead time window refers to the time length used to predict the trend of the minimum curvature radius of the hose over a future period, starting from the current calculation time. The look-ahead time window is preset based on the hose dynamic response time, the ranging array sampling frequency, the MRU sampling frequency, and the risk level of the parallel operation. Defining the Future pessimistic prediction minimum radius of seconds : ; in, The nonlinear redundancy coefficient is estimated from the absolute value of the sliding window slope. Increase the volume of sea state data; Sea state increased Defined as: ; in, As a safety amplification factor for high sea states, For curvature sensitivity, The root mean square of the composite acceleration for the 10-20s sliding window is calculated from the triaxial linear acceleration output by the MRU. To determine whether the predicted minimum radius is acceptable, specifically: set the ultimate failure radius based on hose bending failure tests or ultimate bending data. Determine whether the predicted minimum radius is greater than the limit failure radius; if so, output the predicted minimum radius; if not, the predicted minimum radius data is incorrect, and the sea state expansion and look-ahead time window should be adjusted, and then the minimum radius prediction in step S4 should be performed again.

[0012] Preferably, the The calculation method is as follows: Triaxial linear acceleration measured by MRU , , The resultant acceleration is defined as: ; Then calculate its root mean square value within a 10-20s look-ahead time window: .

[0013] Preferably, the curvature sensitivity Obtained from calibration data during the debugging period, specifically: Data was collected over several time periods under different sea conditions and operational conditions. Data, with the average minimum radius of curvature in the low sea state stable segment. As a reference radius, the radius deduction is calculated as follows: ; Again The data is linearly fitted, and the absolute value of the fitted slope is used as a candidate sensitivity. The 95th percentile of the absolute value of the fitted slope is selected as the sensitivity. ; The aforementioned low sea state stable period refers to a continuous time period during the commissioning period where the amplitude of hull motion is relatively small and the minimum radius of curvature of the hose changes smoothly; specifically: The criteria for judging low sea state are: preset low sea state threshold, attitude threshold for roll and pitch, and ranging efficiency threshold. When the root mean square of the composite acceleration within the 10-20s sliding window is less than the preset low sea state threshold, the root mean square of roll and pitch is less than the preset attitude threshold, and the ranging efficiency is not lower than the preset efficiency threshold, the time period is judged to be in low sea state. The criteria for determining the stable segment are as follows: a preset minimum radius of curvature change rate threshold and a fluctuation threshold are set. Within a continuous time of not less than 30-60 seconds, the ranging efficiency is not less than 95%, the absolute value of the sliding window slope of the current minimum radius of curvature is less than the preset change rate threshold, and the coefficient of variation of the root mean square of the synthesized acceleration is less than the preset fluctuation threshold. The present invention employs the above-mentioned method for inverting the radius of curvature distribution of wet transport hoses used in parallel shipping, and its beneficial effects are as follows: (1) This invention extracts discrete point arrays of hose centerline by fusing ranging array with MRU six degrees of freedom, and replaces local point values ​​in existing schemes with overall three-dimensional radius of curvature distribution, which significantly reduces false alarms and missed alarms in hose bending monitoring and prediction in old ship berthing wet transport. (2) This invention innovatively establishes a formula for predicting the minimum radius based on the trend term and the sea state amplification based on the look-ahead time window, which supports the monitoring and prediction of hose bending under high sea state conditions; Attached Figure Description

[0014] Figure 1 This is the main flowchart of the method for inverting the radius of curvature of a wet transport hose used in parallel transport of ships according to the present invention; Figure 2 This is a schematic diagram illustrating the specific operation of step S1 in the method for inverting the radius of curvature of a wet transport hose alongside a ship according to the present invention. Figure 3 This is a schematic diagram illustrating step S2 of the present invention, which is a method for inverting the radius of curvature of a wet transport hose used for berthing of ships. Figure 4 This is a schematic diagram illustrating the specific operation of step S3 in the method for inverting the curvature radius distribution of wet transport hoses used in parallel operations of the present invention. Figure 5 This is a schematic diagram of the instrument arrangement for the inversion method of the curvature radius distribution of a wet transport hose used in parallel transport of ships according to the present invention. Detailed Implementation

[0015] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments and the accompanying drawings. It should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0016] like Figure 1 As shown in the figure, an embodiment of the present invention provides a method for inverting the radius of curvature distribution of wet transport hoses used for parallel berthing of ships, comprising the following steps: S1. As Figure 2 and Figure 5 As shown.

[0017] S111. Distance measuring arrays are arranged at the edges of the decks of the two ships respectively, forming opposing or intersecting distance measuring bundles facing the area crossed by the hose, covering the range of possible lateral swaying and vertical undulation of the hose.

[0018] The ranging array can employ laser ranging, millimeter-wave ranging, or ultrasonic ranging units; each vessel is equipped with 8-16 ranging units, evenly spaced along the direction of the flexible hose, with a spacing of 0.3-0.8m; the beamline pitch angle is 10°-35°, and the left and right coverage angle is no less than twice the lateral swing range of the flexible hose; the working distance is 4-25m; the sampling frequency is 50-200Hz. The sampling frequency of the MRUs on both vessels is the same as or an integer multiple thereof as the sampling frequency of the ranging array.

[0019] The collapsible reference coordinate system refers to the common coordinate system used during ramming operations between two ships to uniformly describe the spatial morphology and relative motion of their deck equipment and hoses. Specifically, it involves establishing a reference coordinate system with a fixed reference point on one ship's deck, where the x-axis points towards the bow, the y-axis points towards the starboard side, and the z-axis is vertically upward. External parameter calibration of the ranging array is performed using a fixed target or calibration rod to obtain data for each ranging unit. The installation points of each ranging unit are The unit vector of the beamline direction is Zero bias is The zero-bias drift was verified using a static segment; and the coordinates of the other ship's equipment, the ranging array coordinates, and the hose point cloud were uniformly registered into this coordinate system through rigid body transformation.

[0020] S112. Preset the data range, distance jump threshold, and echo quality factor threshold for the ranging echo; acquire ranging echoes. and echo quality factor ,when Less than the preset echo quality factor threshold or Not within the preset data range or If the distance jump exceeds the preset threshold, the ranging echo is deemed invalid and discarded, and the ranging unit status is checked.

[0021] The echo quality factor is a dimensionless index used to evaluate the reliability of single-beam ranging echoes. It is obtained by normalizing the ranging matrix echo intensity, confidence level, and signal-to-noise ratio and mapping it. The preferred normalization value range is 0-1. The larger the value, the more reliable the ranging echo. S121. Each ship is equipped with an MRU to output real-time data on pitch, sway, heave, roll, pitch, and bow motion, which are used for unified timescale of ranging echoes and platform motion compensation.

[0022] S122. For the MRU output poses of ships A and B, determine whether the motion of the two ships is stable. If not, stop immediately. If so, perform drift removal and short-window filtering to obtain the compensated pose, and construct the rigid body transformation accordingly. , It is used to uniformly map the distance measurement beamline observations in the deck coordinate system of two ships to the reference coordinate system, thereby eliminating the influence of the six degrees of freedom motion of the hull on the distance measurement point cloud, and realizing the spatial alignment and fusion inversion of the distance measurement data of the two ships.

[0023] S13. Based on the six-degree-of-freedom pose data of the two ships, the ranging echoes are uniformly mapped to the reference coordinate system and the effective ranging beam is output.

[0024] S2. For example Figure 3 As shown.

[0025] S21. For any valid ranging beam, construct the beamline back projection constraint points. The expression is: ; in, For rigid body transformations corresponding to hull A or B. For the first The installation point of each ranging unit, For the first The unit vector of the beamline direction of each ranging unit. For the first Zero bias of each ranging unit; The constraint point set is obtained by summing all the constraint points. : ; Based on this, the distance values ​​measured by each sensor on both ships can be transformed into three-dimensional points on the surface of the hose in the same coordinate system.

[0026] S22. Assume the centerline of the hose is discretized into N nodes. , The nominal arc length spacing is The nominal arc length spacing refers to the pre-defined target arc length interval between adjacent discrete nodes along the curve of the hose centerline, and a value of 0.2-0.8m is recommended; based on the constraint point set Invert the centerline of the hose and construct the ranging inversion objective function. : ; in, For point The shortest distance to the centerline broken line; The robust weights obtained by mapping the echo quality factor are used to suppress the interference of weak echoes, multipath reflections, and non-tube background points on centerline inversion. The smoothing regularization coefficients are used to constrain the smoothness of the hose centerline inversion results and suppress the jagged shape caused by ranging noise and outliers. 10 are preferred -2 -10 0 A more preferable initial value is 0.1; The quasi-inextensible constraint coefficient is used to constrain the arc length between adjacent discrete nodes of the hose centerline to be close to the nominal arc length spacing. A more preferable initial value is 10, or take... ,in The preferred value is 10-100; Let the set of discrete nodes along the centerline of the hose be: ; Let its initial guess be The weighted Gauss-Newton iterative method is used to evaluate the objective function. Minimize by gradually updating node positions. The time interval is obtained as the number of cycles decreases monotonically or tends to converge. The optimal discrete point sequence of the centerline: ; in, For at any time By minimizing the objective function The optimal centerline discrete point sequence is obtained; Take the previous moment optimal solution As an initial guess at the current moment This enables real-time continuous tracking of the hose centerline. The inverted point sequence is then fitted with splines.

[0027] S23. Determine whether the spline fitting effect is acceptable based on the fitting residuals; if yes, output the discrete point sequence of the hose centerline; if no, adjust the smoothing regularization coefficient in the ranging inversion objective function. Quasi-inextensible constraint coefficient Alternatively, adjust the spline tension parameters and repeat step S22 until the centerline is continuous and the residuals are stable. Define the fitting residual as: .

[0028] S3, such as Figure 4 As shown.

[0029] S31, Discrete point list based on the smoothed hose centerline Calculate the radius of curvature distribution.

[0030] Spacing between centerlines according to nominal arc length Resampling is performed to make adjacent discrete points approximately equal in arc length. Specifically, for the first... Centerline node Take its four adjacent points to obtain , , , , Construct a five-point first-order difference vector With the five-point second-order difference vector for: ; ; Define a five-point discrete curvature estimator for: ; Define the radius of curvature : ; in, This is the lower limit threshold for curvature; By using this five-point discrete curvature formula, the amplification effect of local noise and point-sequence micro-jitter on curvature peaks can be more effectively suppressed, thereby obtaining a more stable radius distribution and the current minimum radius.

[0031] S32. Obtain the minimum radius based on the radius of curvature distribution.

[0032] Minimum radius: .

[0033] S4. Introducing sea state amplification and a forward time window, the predicted minimum radius is obtained; such as Figure 4 As shown. Specifically: The look-ahead time window refers to the length of time used to predict the trend of the minimum curvature radius of the hose over a future period, starting from the current calculation time. The look-ahead time window is preset based on the hose dynamic response time, the ranging array sampling frequency, the MRU sampling frequency, and the risk level of the docking operation. The preferred value range is 5-30s, and 10-20s is selected in this embodiment. When the sea state disturbance is strong or the hose bends rapidly, a smaller value is taken, and when it is necessary to increase the early warning margin, a larger value is taken.

[0034] Defining the Future pessimistic prediction minimum radius of seconds : ; in, The nonlinear redundancy coefficient is estimated from the absolute value of the sliding window slope. The absolute value of the current minimum rate of change of radius of curvature is preferred, and the result is obtained by adjusting the value within a 2-3s sliding window. Estimate the absolute value of the slope obtained by linear fitting; The sea state amplification is used to characterize the conservative correction amount for the further reduction of the minimum radius of curvature of the hose due to hull motion and sea state disturbance. Sea state increased Defined as: ; in, This is a safety amplification factor for high sea states. For curvature sensitivity; The resultant acceleration root mean square (RMS) is the resultant acceleration for the 10-20s sliding window, expressed in g, and is used to characterize the average intensity of ship motion and sea state disturbance over the current time period. The resultant acceleration is calculated from the triaxial linear acceleration output by the MRU. To determine whether the predicted minimum radius is acceptable, specifically: set the ultimate failure radius based on hose bending failure tests or ultimate bending data. Determine whether the predicted minimum radius is greater than the limit failure radius; if so, output the predicted minimum radius; if not, the predicted minimum radius data is incorrect, and the sea state expansion and look-ahead time window should be adjusted, and then the minimum radius prediction in step S4 should be performed again.

[0035] The calculation method is as follows: the triaxial linear acceleration is measured by MRU. , , The resultant acceleration is defined as: ; Then calculate its root mean square value within a 10-20s look-ahead time window: ; The larger the value, the more pronounced the hull sway and the stronger the sea disturbance, which usually has a greater adverse effect on hose bending.

[0036] curvature sensitivity The unit is m / g, used to characterize how many meters the minimum radius of curvature of the hose is expected to need to be reduced when the synthetic acceleration increases by 1g. It is obtained from data calibration during the commissioning period, specifically by collecting data over several time periods under different sea states and operational conditions. Data, with the average minimum radius of curvature in the low sea state stable segment. As a reference radius, the radius deduction is calculated as follows: ; Again The data were linearly fitted, and the absolute value of the fitted slope was used as a candidate sensitivity. To improve conservatism, the 95th percentile of the absolute value of the fitted slope was selected as the threshold. . The smaller the value, the weaker the impact of the same sea state change on the minimum radius of curvature of the hose.

[0037] The low sea state stable period refers to a continuous time segment in the commissioning data where the amplitude of hull motion is relatively small and the minimum radius of curvature of the hose changes smoothly; specifically: The criteria for judging low sea state are: preset low sea state threshold (take the low quantile value of the root mean square of the composite acceleration in all samples during the commissioning period, preferably the 20%-30% quantile value, or determined to be 0.05g-0.10g based on field tests), attitude thresholds for roll and pitch, and ranging efficiency threshold. When the root mean square of the composite acceleration within a 10-20s sliding window is less than the preset low sea state threshold, the root mean squares of roll and pitch are both less than the preset attitude threshold, and the ranging efficiency is not lower than the preset efficiency threshold, the time period is judged to be in low sea state. The criteria for determining a stable segment are as follows: a preset minimum radius of curvature change rate threshold (preferably 0.01-0.03 m / s), a fluctuation threshold of the root mean square of the composite acceleration (preferably 10%-15%), and a time period of no less than 30-60 s in which the ranging efficiency is no less than 95%, the absolute value of the sliding window slope of the current minimum radius of curvature is less than the preset rate of change threshold, and the coefficient of variation of the root mean square of the composite acceleration is less than the preset fluctuation threshold. In the samples that meet the above conditions of low sea state and stable section, the mean minimum radius of curvature is calculated and used as the reference radius.

[0038] Safety amplification factor at high sea states , is a dimensionless coefficient used in , In addition to the basic deduction, a certain safety margin is added to ensure that the prediction results remain conservative in the case of high sea state, measurement errors, or incomplete modeling. The setting should be determined based on on-site experience, debugging results, or test data. The optimal value is 1.0-1.5. A larger value is used when the sea conditions are poor and the risk is high, and a smaller value is used when the sea conditions are stable and the model is reliable.

[0039] Therefore, this invention adopts the above-mentioned method for inverting the curvature radius distribution of hoses in wet transport alongside ships. By fusing a ranging array with the MRU six degrees of freedom, it extracts the discrete point series of the hose centerline and replaces the local point values ​​in the existing scheme with the overall three-dimensional curvature radius distribution. This significantly reduces the false alarms and missed alarms in the monitoring and prediction of hose bends in the old wet transport alongside ships. It also innovatively establishes a prediction minimum radius formula based on the trend term and sea state amplification based on the look-ahead time window, supporting the monitoring and prediction of hose bends under high sea states. It is worth noting that all contents not described in detail in this invention are existing technologies and are well known to those skilled in the art.

[0040] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for inverting the radius of curvature distribution of wet transport hoses used in parallel berthing of ships, characterized in that, Includes the following steps: S1. Obtain multiple synchronous ranging echoes in the hose crossing area through the ranging array arranged at the edge of the decks of the two ships, and combine them with the six-degree-of-freedom pose data of the MRU of the two ships to complete time synchronization and platform motion compensation, and obtain an effective ranging beam. S2. Perform beamline back projection and fusion inversion on the effective ranging beam in the motion-compensated parallel reference coordinate system to extract the discrete point series of the hose centerline. S3. Based on the discrete point array of the hose centerline, the curvature radius distribution is calculated using the discrete curvature formula, and the minimum radius is obtained; S4. Incorporate the minimum radius into the sea state amplification and look-ahead time window to obtain the predicted minimum radius; Specifically, S1 is: The six-degree-of-freedom pose data includes sway, roll, heave, pitch, pitch and yaw motion data; S111. Arrange a ranging array on both sides of the deck edge of the hose crossing area between the two ships, and establish and attach a reference coordinate system. S112. Acquire ranging echo and echo quality factor, and determine whether the ranging echo validity is acceptable; if yes, proceed to step S13; if no, remove invalid data and check the ranging unit status, and then reacquire ranging echo and echo quality factor. The echo quality factor is a dimensionless index used to evaluate the reliability of single-beam ranging echoes, which is obtained by normalizing the ranging matrix echo intensity, confidence level, and signal-to-noise ratio. S121. Motion reference units (MRUs) are arranged on the decks of both ships; S122. Collect the six-degree-of-freedom pose data of the two ships, and determine whether the motion of the two ships is stable based on the pose data. If yes, proceed to step S13; otherwise, stop the machine immediately. S13. Based on the six-degree-of-freedom pose data of the two ships, map the ranging echoes to the reference coordinate system and output the effective ranging beam. The aforementioned berthing reference coordinate system refers to a common coordinate system used during berthing operations to uniformly describe the spatial morphology and relative motion of the deck equipment and hoses of the two vessels. Specifically, it involves establishing a reference coordinate system with a fixed reference point on one vessel's deck, where the x-axis points towards the bow, the y-axis points towards the starboard side, and the z-axis is vertically upward. External parameter calibration of the ranging array is performed using a fixed target or calibration rod to obtain data for each ranging unit. Zero-bias drift is then verified using a static segment. The first... The installation points of each ranging unit are The unit vector of the beamline direction is Zero bias is The coordinates of the equipment on the other ship, the coordinates of the ranging array, and the point cloud of the hose are uniformly registered to the reference coordinate system through rigid body transformation. The specific steps for determining the validity of the ranging echo are as follows: Preset the data range, distance jump threshold, and echo quality factor threshold for the ranging echo, and then acquire the ranging echo. and echo quality factor ;when Less than the preset echo quality factor threshold or Not within the preset data range or If the distance jump exceeds a preset threshold, the ranging echo is considered invalid. Specifically, S2 is: S21. For any valid ranging beam, construct the beamline back projection constraint points. The expression is: ； in, For rigid body transformations corresponding to hull A or B. For the first The installation point of each ranging unit, For the first The unit vector of the beamline direction of each ranging unit. For the first Zero bias of each ranging unit; The constraint point set is obtained by summing all the constraint points. ; S22. Invert the discrete point sequence of the hose centerline based on the constraint point set and perform spline fitting; Discretize the centerline of the hose into N nodes. , The nominal arc length spacing is The nominal arc length spacing refers to the pre-set target arc length interval between adjacent discrete nodes along the curve direction of the hose centerline, which is taken as 0.2-0.8m; based on the constraint point set Invert the centerline of the hose and construct the ranging inversion objective function. : ； in, For point The shortest distance to the centerline broken line; The robust weights are obtained by mapping the echo quality factor. For smoothing regularization coefficients; The quasi-inextensible constraint coefficient; Let the set of discrete nodes along the centerline of the hose be: ； Let its initial guess be The weighted Gauss-Newton iterative method is used to evaluate the objective function. Minimize by gradually updating node positions. The time interval is obtained as the number of cycles decreases monotonically or tends to converge. The optimal discrete point sequence of the centerline: ； in, For at any time By minimizing the objective function The optimal centerline discrete point sequence is obtained; Take the previous moment optimal solution As an initial guess at the current moment This enables real-time continuous tracking of the hose centerline. The inverted point sequence is then spline-fitted. S23. Define the fitting residuals and determine whether the spline fitting effect is acceptable based on the fitting residuals; if yes, output the discrete point sequence of the hose centerline; if no, adjust the smoothing regularization coefficient in the ranging inversion objective function. Quasi-inextensible constraint coefficient Or determine the spline tension parameter, and then proceed to step S22; The conditions for acceptable spline fitting are that the centerline is continuous and the residuals are stable. The fitting residual is: 。 2. The method for inverting the radius of curvature distribution of a wet transport hose used for alongside ships according to claim 1, characterized in that, The ranging array employs laser ranging, millimeter-wave ranging, or ultrasonic ranging units; each vessel is equipped with 8-16 ranging units, evenly spaced along the direction of the hose crossing, with a spacing of 0.3-0.8m; the beam pitch angle is 10°-35°, and the left and right coverage angles are not less than twice the lateral swing range of the hose; the working distance is 4-25m; and the sampling frequency is 50-200Hz. The sampling frequency of the MRU on both ships is the same as or an integer multiple of the sampling frequency of the ranging array.

3. The method for inverting the radius of curvature distribution of a wet transport hose used for ship berthing according to claim 1, characterized in that, Specifically, S3 is: S31. Based on the discrete point sequence of the hose centerline, the radius of curvature distribution is calculated using the five-point discrete curvature formula, specifically: For the Centerline node Take its four adjacent points to obtain , , , , Define a five-point first-order difference vector. With the five-point second-order difference vector for: ； ； Define a five-point discrete curvature estimator for: ； Define radius of curvature : ； in, This is the lower limit threshold for curvature; S32, Obtain the minimum radius: 。 4. The method for inverting the radius of curvature distribution of a wet transport hose used for alongside ships according to claim 3, characterized in that, Specifically, S4 is: The look-ahead time window refers to the time length used to predict the trend of the minimum curvature radius of the hose over a future period, starting from the current calculation time. The look-ahead time window is preset based on the hose dynamic response time, the ranging array sampling frequency, the MRU sampling frequency, and the risk level of the parallel operation. Defining the Future pessimistic prediction minimum radius of seconds : ； in, The nonlinear redundancy coefficient is estimated from the absolute value of the sliding window slope. Increase the volume of sea state data; Sea state expansion Defined as: ； in, As a safety amplification factor for high sea states, For curvature sensitivity, The root mean square of the composite acceleration for the 10-20s sliding window is calculated from the triaxial linear acceleration output by the MRU. To determine whether the predicted minimum radius is acceptable, specifically: set the ultimate failure radius based on hose bending failure tests or ultimate bending data. Determine whether the predicted minimum radius is greater than the limit failure radius; if so, output the predicted minimum radius; if not, the predicted minimum radius data is incorrect, and the sea state expansion and look-ahead time window should be adjusted, and then the minimum radius prediction in step S4 should be performed again.

5. The method for inverting the radius of curvature distribution of a wet transport hose used for alongside ships according to claim 4, characterized in that, The The calculation method is as follows: Triaxial linear acceleration measured by MRU , , The resultant acceleration is defined as: ； Then calculate its root mean square value within a 10-20s look-ahead time window: 。 6. The method for inverting the radius of curvature distribution of a wet transport hose used for alongside ships according to claim 4, characterized in that, curvature sensitivity Obtained from calibration data during the debugging period, specifically: Data was collected over several time periods under different sea conditions and operational conditions. Data, with the average minimum radius of curvature in the low sea state stable segment. As a reference radius, the radius deduction is calculated as follows: ； Again The data is linearly fitted, and the absolute value of the fitted slope is used as a candidate sensitivity. The 95th percentile of the absolute value of the fitted slope is selected as the sensitivity. ; The low sea state stable segment refers to a continuous period of time during the commissioning period where the amplitude of hull motion is small and the minimum radius of curvature of the flexible hose changes smoothly. Specifically, the criteria for judging low sea state are: preset low sea state threshold, roll and pitch attitude threshold, and ranging efficiency threshold. When the root mean square of the composite acceleration within a 10-20s sliding window is less than the preset low sea state threshold, the root mean squares of roll and pitch are both less than the preset attitude threshold, and the ranging efficiency is not less than the preset efficiency threshold, the time period is judged to be in low sea state. The criteria for judging stable segment are: preset minimum radius of curvature change rate threshold and fluctuation threshold. Within a continuous period of not less than 30-60s, the time period in which the ranging efficiency is not less than 95%, the absolute value of the sliding window slope of the current minimum radius of curvature is less than the preset change rate threshold, and the coefficient of variation of the root mean square of the composite acceleration is less than the preset fluctuation threshold is considered a stable segment.

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