Multi-parameter cooperative control method for underwater propeller turning and hoisting

Abstract

The application discloses a multi-parameter cooperative control underwater propeller turning-over hoisting pipe control method and particularly relates to the field of underwater propeller hoisting, and is used for solving the problem of unstable propeller turning-over control under tidal disturbance, and is achieved by the following steps: the turning-over dynamic state of the propeller is monitored through the curvature acceleration difference and the tension phase drift amount, the iteration interval of the high-risk section is compressed in time by means of adaptive step mapping, the angle increment and the target tension are corrected simultaneously before the winch action by using the prediction correction cycle, the angle adjustment, the tension adjustment and the environmental safety three-line linkage are realized, the safety margin diagram is continuously refreshed under the driving of the vibration and the flow velocity double signal sources, once the node approaches the warning domain, the step rollback is triggered, and the potential oscillation is blocked in the budding stage. The synchronous reliable coefficient runs through the whole process, the winch synchronization quality is evaluated, the step mapping is real-time authorized, and then the convergence path is kept close to the real balance channel. Therefore, the turning-over time length is shortened, and the tension fluctuation amplitude is stabilized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of underwater propeller hoisting, and more particularly to a multi-parameter collaborative control method for hoisting an underwater propeller. BACKGROUND

[0002] The hoisting operation of an underwater propeller must be completed in an unstable tidal current and low-visibility water environment. The mechanical relationship between the winch, the sling and the propeller changes in real time with the roll angle. The operator must rely on continuous calculation results to select the winch speed and tension distribution to maintain the smooth transition of the propeller posture. This operation emphasizes the synchronization of angle and force. Any instruction delay or deviation will directly translate into alternating loads on the steel cable, which will affect the integrity of the sealing cover and the safety of the ship.

[0003] However, the current control method usually uses fixed or empirical steps for step-by-step iteration, without fully considering the superimposed effects of roll curvature mutation and tension phase misalignment. The algorithm convergence path repeatedly swings on the high-order constraint surface, which easily triggers the winch to reverse frequently. The tension peak value coincides with the environmental disturbance instantaneously, which prolongs the operation window and increases the risk of cable breakage.

[0004] To solve the above problems, a technical solution is provided. SUMMARY

[0005] To overcome the above-mentioned defects of the prior art, the embodiments of the present application provide a multi-parameter collaborative control method for hoisting an underwater propeller, to solve the problem of unstable control of the propeller roll in the presence of tidal disturbances.

[0006] To achieve the above-mentioned purposes, the present application provides the following technical solutions:

[0007] S1: Collect the roll angle sequence and the sling tension sequence, perform a second difference calculation of the instantaneous curvature, and refine the time interval for the high-curvature section according to the bisection principle to generate an iteration step table and write it into a control unit;

[0008] S2: The control unit reads the iteration step table and the real-time tension value, uses the least squares prediction method to calculate the next roll angle increment and the target tension value, and sends a winch speed instruction;

[0009] S3: During the execution of the winch speed instruction by the winch, first, the curvature acceleration difference value is obtained according to the angular velocity curve and its time derivative, and then the tension phase drift amount of the front and rear slings is calculated by mutual spectrum analysis. The two are input into a pre-set segmented mapping table to output a synchronous reliable coefficient. If the synchronous reliable coefficient is lower than a threshold value, the current iteration step is shortened and the winch speed instruction is refreshed in S2;

[0010] S4: the control unit continuously compares the flow rate monitoring data and the propeller vibration frequency spectrum to construct a safety margin diagram, and if a warning area appears in the safety margin diagram, the iteration step length is also shortened and the prediction correction is returned to S2;

[0011] S5: when the synchronization reliability coefficient is stable and the safety margin diagram remains positive in the continuous loop, the control unit issues a synchronous lifting instruction to complete the roll-over.

[0012] In a preferred embodiment, step S1 includes the following:

[0013] The sensor is used to collect the roll-over angle and tension data at a fixed initial time interval, the instantaneous curvature is calculated by the second-order difference method, the high curvature section is identified according to the curvature threshold, the time interval of the high curvature section is halved to increase the data collection frequency, and an iteration step length table recording each time interval is generated. The iteration step length table, the roll-over angle sequence and the tension sequence are transmitted to the control unit.

[0014] In a preferred embodiment, step S2 includes the following:

[0015] The control unit extracts the step length value of the current time section from the iteration step length table as the current time step length, calculates the roll-over angle increment and the target tension value of the propeller at the next time based on the historical roll-over angle sequence and the historical tension sequence using the least squares prediction method, calculates the winding speed according to the roll-over angle increment and the target tension value using the mechanical model, and sends the winding speed as an instruction to the winding machine to adjust the speed of the hoisting rope.

[0016] In a preferred embodiment, step S3 includes the following:

[0017] During the execution of the winding speed instruction by the winding machine, the control unit monitors the roll-over angle and tension data in real time, calculates the angular velocity and angular acceleration by differentiating the roll-over angle sequence, and compares them with the reference angular acceleration to obtain the curvature acceleration difference.

[0018] In a preferred embodiment, step S3 further includes the following:

[0019] The phase drift amount of the front and rear hoisting rope tension signals is calculated by using the cross-spectrum analysis method; the curvature acceleration difference and the tension phase drift amount are input into a pre-set piecewise mapping table to generate a synchronization reliability coefficient.

[0020] In a preferred embodiment, step S3 further includes the following:

[0021] When the synchronization reliability coefficient is lower than the pre-set threshold, the control unit shortens the iteration step length and returns to step S2 to recalculate the winding speed instruction.

[0022] In a preferred embodiment, step S4 includes the following:

[0023] The control unit collects flow rate monitoring data in the hoisting area in real time through the water flow sensor, and generates a vibration spectrum through frequency domain analysis after collecting the vibration signal on the thruster through the vibration sensor, and constructs a safety margin graph using the flow rate monitoring data and the vibration spectrum, and when the safety margin value is lower than the preset warning threshold, the current iteration step length is shortened and a new hoist speed instruction is generated again in step S2.

[0024] In a preferred embodiment, step S4 further comprises the following contents:

[0025] The safety margin graph takes time as the horizontal axis and safety margin value as the vertical axis, and is determined by calculating the product of the flow rate term ratio and the vibration term.

[0026] In a preferred embodiment, step S5 comprises the following contents:

[0027] The control unit continuously monitors the generated synchronization reliability coefficient and safety margin graph, and judges that the synchronization reliability coefficient remains stable within a predetermined continuous period and the safety margin graph maintains a positive value within a predetermined continuous period.

[0028] In a preferred embodiment, step S5 further comprises the following contents:

[0029] When the conditions that the synchronization reliability coefficient remains stable and the safety margin graph maintains a positive value are both met, the control unit issues a synchronization promotion command to complete the overturning operation, and then archives data storage.

[0030] The technical effects and advantages of the multi-parameter cooperative control underwater thruster overturning and hoisting management method of the present application are as follows:

[0031] The present application monitors the overturning dynamic state through the curvature acceleration difference and the tension phase drift amount, uses adaptive step length mapping to compress the iteration interval of high-risk sections in time, and uses the prediction correction cycle to synchronize the correction of the angle increment and the target tension before the hoisting action, to realize the three-line linkage of angle adjustment, tension adjustment and environmental safety. The safety margin graph is continuously refreshed under the driving of the vibration and flow rate double signal sources, and once the node approaches the warning domain, the step length rollback is triggered, so that the potential oscillation is blocked in the embryonic stage. The synchronization reliability coefficient runs through the whole process, which not only evaluates the hoisting synchronization quality, but also gives real-time power to the step length mapping, so as to keep the convergence path close to the real balance channel. The global cooperative logic eliminates the accumulation of reverse instructions and the concentration of metal fatigue, shortens the overturning time, stabilizes the tension fluctuation amplitude, and retains high-resolution working condition archives in the whole process, providing reliable prior boundary and decision support for subsequent hoisting operations. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 It is a flowchart of the multi-parameter cooperative control underwater thruster overturning and hoisting management method of the present application. DETAILED DESCRIPTION

[0033] The technical solutions in the embodiments of the present application will be apparently and completely described in combination with the drawings of the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by a person of ordinary skill in the art without any creative work fall within the protection scope of the present application.

[0034] Embodiment 1 Figure 1 The method for controlling the turning and lifting of the underwater thruster by the multi-parameter cooperative control is given, which comprises:

[0035] S1: Collecting the turning angle sequence and the sling tension sequence, performing the second difference calculation of the instantaneous curvature, and refining the time interval of the high curvature section according to the bisection principle to generate an iteration step table and write it into a control unit.

[0036] S2: The control unit reads the iteration step table and the real-time tension value, calculates the next turning angle increment and the target tension value by using the least square prediction method, and sends a winch speed instruction.

[0037] S3: During the execution of the winch speed instruction by the winch, first, the curvature acceleration difference value is obtained according to the angular velocity curve and its time differential, and then the tension phase drift amount of the front and rear slings is calculated by using the cross-spectrum analysis, and the two are input into a preset segmented mapping table to output a synchronous reliable coefficient. If the synchronous reliable coefficient is lower than a threshold value, the current iteration step is shortened and the winch speed instruction is refreshed by returning to S2.

[0038] S4: The control unit continuously compares the flow rate monitoring data and the thruster vibration spectrum to construct a safety margin diagram. If the safety margin diagram appears in a warning area, the iteration step is also shortened and the prediction correction is performed by returning to S2.

[0039] S5: When the synchronous reliable coefficient is stable and the safety margin diagram remains positive in the continuous cycle, the control unit issues a synchronous lifting instruction to complete the turning.

[0040] The underwater propeller turning-over lifting operation is a high-difficult task performed in a complex underwater environment, which needs to cope with unstable tidal current, low water visibility and other unfavorable conditions. During the lifting process, the mechanical relationship between the winch, the sling and the propeller is dynamically adjusted in real time with the real-time change of the turning angle. The operator must determine the winch speed and tension distribution through continuous calculation to ensure the smooth transition of the propeller posture. Angle-force synchronization is the core requirement of this operation. If the command delay or deviation occurs, it may cause the steel strand to bear alternating loads, thereby threatening the integrity of the sealing cover and the safety of the ship. The traditional method mostly uses fixed step or experience step for control, which fails to fully consider the superimposed effect of turning curvature mutation and tension phase misalignment, and is easy to cause algorithm convergence instability, winch frequent reversal and other problems, which prolongs the operation time and increases the risk of broken cable.

[0041] The present application provides a multi-parameter cooperative control underwater propeller turning-over lifting management and control method. By real-time acquisition of turning angle and sling tension data, combined with adaptive step adjustment and prediction correction technology, the cooperative optimization of angle adjustment, tension regulation and environmental safety is realized. Step S1 as the starting point of the whole process is responsible for generating the iteration step table, providing accurate time reference for the subsequent steps, and ensuring that the control command can adapt to the dynamic changes of the turning-over process.

[0042] Step S1 includes the following contents:

[0043] S1-1, data acquisition:

[0044] Firstly, the turning angle sequence of the propeller and the tension sequence of the sling are acquired in real time by the angle sensor installed on the propeller and the tension sensor on the sling. The turning angle sequence of the propeller is used to reflect the posture change of the propeller during the lifting process, and the tension sequence of the sling is used to reflect the stress state of the sling. During the acquisition process, data is recorded once every fixed initial time interval, for example, every 0.1 second, forming discrete turning angle sequence data set and tension sequence data set. These data sets provide original input for subsequent instantaneous curvature calculation and high curvature section identification.

[0045] S1-2, instantaneous curvature calculation:

[0046] In order to quantify the change rate of the turning angle sequence, the instantaneous curvature is calculated by using the second difference method. The instantaneous curvature reflects the acceleration of the turning angle change, which is used to identify the key sections of the dynamic change of the propeller turning-over process. The specific calculation process is as follows:

[0047] For each time point in the sequence of roll-over angles, take the angle value at this time point, subtract the angle value at the previous time point, to get the first difference; then take the angle value at the next time point, subtract the angle value at this time point, to get the second difference; then divide the difference between the first difference and the second difference by the square of the initial time interval, to get the instantaneous curvature value at this time point. This method simulates the second-order rate of change of the angle change by numerical approximation, generating an instantaneous curvature sequence.

[0048] The second-order difference method can effectively capture the acceleration trend of the roll-over angle sequence, and can better reflect the severity in the dynamic process than the first-order difference. Calculating the instantaneous curvature sequence provides a quantitative basis for subsequent high-curvature segment identification, ensuring that the control system can accurately judge the dynamic characteristics of the thruster roll-over.

[0049] S1-3, High Curvature Segment Identification and Step Refinement:

[0050] According to the instantaneous curvature sequence, set a curvature threshold, for example 0.05 rad / s^2, to distinguish high-curvature segments and low-curvature segments. For each time point in the instantaneous curvature sequence, if the instantaneous curvature value at this time point exceeds the curvature threshold, it is determined that this time point belongs to the high-curvature segment, indicating that the roll-over angle changes dramatically; if the instantaneous curvature value does not exceed the curvature threshold, it is determined that this time point belongs to the low-curvature segment, indicating that the roll-over angle changes smoothly. For high-curvature segments, halve the current time interval, for example from 0.1 seconds to 0.05 seconds, to increase the frequency of data acquisition and control; for low-curvature segments, maintain the initial time interval unchanged.

[0051] By distinguishing high-curvature segments and low-curvature segments through the curvature threshold, the time resolution can be adjusted according to the actual dynamic characteristics of the thruster roll-over process. The step refinement of high-curvature segments improves the density of data acquisition and the accuracy of control, ensuring timely response during the stage of dramatic roll-over angle change; maintaining a larger step for low-curvature segments reduces unnecessary computational burden and improves overall processing efficiency.

[0052] S1-4, Iterative Step Table Generation:

[0053] According to the results of high-curvature segment identification and step refinement, generate an iterative step table to record the time step of each time segment. The iterative step table presents the time segment and the corresponding step in the form of pairs, for example, the step of a certain time segment is 0.1 seconds, and the step of another time segment is 0.05 seconds. The generation process is: traverse the instantaneous curvature sequence, associate the high-curvature or low-curvature attribute of each time point with its corresponding time step in chronological order, organize it into a continuous time-step pair list, and form a complete iterative step table.

[0054] The iterative step table realizes the dynamic allocation of time resolution, and clearly records the control requirements of each time segment in the propeller turning process.

[0055] S1-5, data write control unit:

[0056] The generated iterative step table, flip angle sequence and tension sequence are transmitted to the control unit. The control unit determines the calculation frequency of each time segment according to the iterative step table, and uses the flip angle sequence and tension sequence to generate the prediction and control instruction of the propeller turning state. The transmission process ensures that the time-step pairs in the iterative step table, the angle values in the flip angle sequence and the tension values in the tension sequence are transmitted in time sequence, to support the real-time processing of the control unit.

[0057] The iterative step table, flip angle sequence and tension sequence are input into the control unit together, providing comprehensive information required for propeller turning control. The iterative step table sets a dynamic time reference for the control unit, and the flip angle sequence and tension sequence provide real-time state data, enabling the control unit to adjust the instruction dynamically according to the actual situation, thereby improving the safety and efficiency of the hoisting operation.

[0058] Step S1 generates the iterative step table by collecting the flip angle sequence and the sling tension sequence, and adjusts the step length adaptively based on the instantaneous curvature, providing a dynamic time reference for subsequent control. However, relying solely on step length adjustment is insufficient to cope with the complex dynamic relationship between flip angle and tension during the turning process, as well as the influence of environmental factors such as tidal current disturbance. Step S2, as the core link of the control process, needs to generate accurate winch speed instructions using real-time data and prediction models to ensure smooth transition of the propeller attitude and stability of the sling tension.

[0059] The processing technology logic of step S2 aims to accurately adjust the propeller turning process through the control unit, generate winch speed instructions using input parameters, and ensure the coordinated control of flip angle and sling tension. The following is the detailed processing process.

[0060] Step S2 includes the following:

[0061] S2-1, determine the current time step:

[0062] The control unit first extracts the step length value corresponding to the current time segment from the iterative step table, called the current time step. The iterative step table is generated by step S1, recording the calculation step length of each time segment, used to guide the update frequency of the control instruction. The determination of the current time step directly affects the time resolution of the prediction model and the sending rhythm of the winch speed instruction. By reading the pre-set step length value, the control unit can adjust the calculation and control frequency according to the dynamic requirements of the turning process, ensuring the timely response of the system to the changes in the propeller attitude.

[0063] The current time step is determined using a predetermined value in the iteration step table, which can flexibly adjust the control rhythm according to different stages of the turning process, avoiding response delay or excessive frequent calculation caused by fixed step length, thereby improving the adaptability and efficiency of the control system.

[0064] S2-2, predicting the turning angle increment and target tension value at the next time:

[0065] The control unit uses the least squares prediction method to calculate the turning angle increment and target tension value at the next time based on the historical turning angle sequence and historical tension sequence. The historical turning angle sequence records the turning angle of the thruster at past time points; the historical tension sequence records the tension value of the sling at past time points, both of which are provided by step S1. The turning angle increment represents the change in turning angle of the thruster at the next time relative to the current time; the target tension value represents the ideal tension value that the sling should reach at the next time, in Newton. The calculation idea of the least squares prediction method is to find a mathematical model that best describes the relationship between the historical turning angle sequence and the historical tension sequence by analyzing the trend of the data. Specifically, this method compares the deviation of the predicted value from the historical data, and adjusts the sum of squares of all deviations to the minimum to determine the characteristic coefficients of the model, thereby calculating the predicted value at the next time.

[0066] Using the least squares prediction method can fully utilize the dynamic information in the historical turning angle sequence and the historical tension sequence, and accurately capture the mutual influence between the turning trend of the thruster and the tension change. This method provides forward-looking prediction through trend analysis of historical data, ensuring smooth transition of thruster attitude and stable control of sling tension, thereby improving the reliability and accuracy of the system.

[0067] S2-3, calculating the hoisting speed:

[0068] The control unit calculates the required hoisting speed using a mechanical model based on the predicted turning angle increment and target tension value. The mechanical model takes into account the mass of the thruster, the stiffness of the sling, and the geometric relationship during the turning process. The calculation process first multiplies the predicted turning angle increment by the effective length of the sling to obtain the displacement amount that the sling needs to adjust during the turning process of the thruster; then, the displacement amount is divided by the current time step to obtain the basic hoisting speed. Next, according to the target tension value, the basic hoisting speed is adjusted by the correction factor calibrated through experiments to ensure that the tension of the sling can be maintained within the predicted target range. This adjustment takes into account the nonlinear relationship between tension and speed, ensuring that the control command can not only realize the change in turning angle, but also meet the stability requirements of tension.

[0069] The calculated hoisting speed can convert the predicted roll angle increment and target tension value into specific execution instructions. This method combines physical laws and experimental data to ensure that the calculation results meet the movement needs of the thruster and maintain the dynamic balance of the sling tension, thereby ensuring the safety and control accuracy of the roll-over process.

[0070] S2-4, send hoisting speed instruction:

[0071] The control unit sends the calculated hoisting speed as an instruction to the winch for guiding the adjustment of the sling's winding and unwinding speed, thereby realizing control over the thruster's roll-over process. The hoisting speed instruction is in units of meters per second, directly driving the operation of the winch. The sending process ensures real-time communication between the control unit and the execution mechanism, enabling the system to adjust the thruster's posture and the sling's tension state in a timely manner based on the calculation results.

[0072] Step S2 is closely linked in context between steps S1 and S3. The iterative step table, historical roll angle sequence, and historical tension sequence generated in step S1 are directly used as input parameters for step S2, ensuring the continuity and consistency of data sources. The hoisting speed instruction calculated in step S2 is passed to step S3 for synchronous evaluation during execution. Step S3 calculates the synchronization reliability coefficient by analyzing the angular velocity curve and the tension phase shift. If the synchronization reliability coefficient is below the preset threshold, it indicates that the current control effect is insufficient, and step S3 will shorten the current time step and require step S2 to recalculate the hoisting speed instruction. This feedback mechanism enables step S2 to dynamically adjust the control instructions based on the actual execution situation, ensuring the real-time and stability of the roll-over process.

[0073] Step S2 uses the iterative step table and real-time tension value to calculate the roll angle increment and target tension value at the next time using the least squares prediction method, and generates the hoisting speed instruction. However, due to factors such as tidal disturbance, water damping, and system response delay, the hoisting speed instruction may deviate from the expected value during actual execution, resulting in a loss of synchronization between the roll angle and tension distribution, and thus affecting the stability of the thruster's posture. Therefore, step S3, as a key link for real-time monitoring and feedback, quantifies the synchronization effect by evaluating the curvature acceleration difference and tension phase shift, and adjusts the iterative step size as needed to ensure the smoothness and safety of the roll-over process.

[0074] The processing technology logic of step S3 aims to ensure the synchronization and stability of the thruster's roll-over process by real-time monitoring and evaluating the effect of the winch executing the hoisting speed instruction. Based on real-time data and preset rules, the control unit calculates key indicators and dynamically adjusts control parameters to achieve smooth transition of the thruster's posture and stable control of the sling tension. The following is the detailed processing process.

[0075] Step S3 includes the following:

[0076] S3-1, Calculate the curvature acceleration difference value:

[0077] The control unit first calculates the instantaneous angular velocity and angular acceleration using the flip angle sequence. The flip angle sequence records the flip angles of the propeller at different time points. The instantaneous angular velocity is obtained by analyzing the rate of change of the flip angle sequence over time, indicating the speed of the propeller flip. The angular acceleration is then calculated by calculating the rate of change of the instantaneous angular velocity over time, indicating the size of the propeller flip acceleration. Next, the reference angular acceleration is introduced, which is derived from the next flip angle increment calculated based on the least squares prediction method in step S2, reflecting the angular acceleration that the propeller should achieve in the ideal state. By subtracting the actual calculated angular acceleration from the reference angular acceleration, the curvature acceleration difference value is obtained. The curvature acceleration difference value represents the deviation between the actual execution effect and the prediction model, and is used to evaluate the synchronization of the propeller flip process.

[0078] The calculation of the curvature acceleration difference value can quantify the deviation between the actual motion state and the expected state during the propeller flip process. Combined with the real-time collected flip angle sequence and the reference angular acceleration generated by prediction, the monitoring result has both accuracy and foresight, providing a reliable basis for subsequent synchronization evaluation and effectively improving the response ability of the control system.

[0079] S3-2, Calculate the tension phase shift amount:

[0080] The control unit performs frequency domain analysis on the tension sequences of the front and rear slings to calculate the tension phase shift amount. The tension sequences of the front and rear slings respectively record the tension values of the front and rear slings at different time points. First, the control unit uses the cross-spectral analysis method to convert the tension sequences of the front and rear slings into frequency domain signals, generating a cross-spectral function. The cross-spectral function describes the correlation of the front and rear sling tension signals at different frequencies. Then, by analyzing the cross-spectral function, the tension phase shift amount is calculated, representing the phase difference of the front and rear sling tension signals in the frequency domain. The size of the tension phase shift amount reflects the synchronization degree of the tension changes of the front and rear slings, and the smaller the phase shift amount, the higher the synchronization, and vice versa.

[0081] Cross-spectral analysis is a signal processing technique used to analyze the correlation and phase relationship between two signals. By calculating the cross-spectrum of two signals, which is the conjugate product of the Fourier transforms of the two signals, the interaction between the two signals at different frequencies is revealed. Cross-spectrum provides information on the amplitude and phase difference between signals, allowing identification of signal synchronization, delay or phase shift. This method is widely used in fields such as vibration analysis, acoustics, biomedical engineering, etc., to evaluate system dynamic characteristics or detect abnormal states.

[0082] The tension phase shift amount is calculated by frequency domain analysis to evaluate the synchronization of the change in the sling tension before and after, which makes up for the limitation of relying only on time domain analysis. The dynamic characteristics of the change in the tension can be captured, and the synchronization is comprehensively evaluated, so that the accuracy and stability of the tension control during the turning process of the propeller are improved.

[0083] S3-3, generating a synchronization reliability coefficient:

[0084] The control unit inputs the curvature acceleration difference and the tension phase shift amount into a preset segmented mapping table to generate a synchronization reliability coefficient. The synchronization reliability coefficient is a dimensionless value ranging from 0 to 1, and the closer the value is to 1, the better the synchronization during the turning process of the propeller. The segmented mapping table divides multiple intervals according to the amplitude range of the curvature acceleration difference and the tension phase shift amount, and assigns a corresponding synchronization reliability coefficient to each interval. For example, when the curvature acceleration difference and the tension phase shift amount are both within a preset ideal range, the synchronization reliability coefficient is 1; when either parameter exceeds the ideal range, the synchronization reliability coefficient decreases by a preset proportion.

[0085] The "segmented mapping table" in the present application is a pre-set tool for converting the curvature acceleration difference and the tension phase shift amount into a synchronization reliability coefficient to evaluate the synchronization effect during the turning process. Specifically, this function is achieved by dividing the amplitude of the curvature acceleration difference and the tension phase shift amount into multiple intervals and assigning a corresponding synchronization reliability coefficient value to each interval. This mapping relationship is based on experimental data and the calibration of system characteristics to ensure the objectivity and consistency of the evaluation results. For example, when the curvature acceleration difference and the tension phase shift amount are both within the ideal range, the synchronization reliability coefficient is set to 1, indicating the best synchronization effect; and when the difference or the shift amount gradually increases, the synchronization reliability coefficient decreases proportionally, and the minimum value is 0, reflecting the decline in synchronization. By using this segmented mapping method, the synchronization evaluation process is simplified, and the control unit can quickly and accurately determine the synchronization state of the turning process and adjust the system operation in real time based on the results, thereby improving the overall performance and reliability.

[0086] Generating a synchronization reliability coefficient integrates the curvature acceleration difference and the tension phase shift amount into a single quantitative indicator, which facilitates quick judgment of the synchronization effect during the turning process. Using a segmented mapping table ensures the objectivity and consistency of the evaluation process, allowing the control unit to make decisions efficiently based on the synchronization reliability coefficient, thereby optimizing the control accuracy of the propeller turning process.

[0087] S3-4, judging and adjusting the iteration step:

[0088] The control unit compares the synchronization reliability coefficient with a preset synchronization reliability coefficient threshold, for example, the threshold is set to 0.8. If the synchronization reliability coefficient is greater than or equal to the threshold, it indicates that the current execution effect of the thruster roll-over process is good, and the control unit keeps the current iteration step length unchanged and continues to execute the subsequent steps. The iteration step length is provided by the iteration step length table generated in step S1. If the synchronization reliability coefficient is less than the threshold, it indicates that the synchronization is insufficient, and the control unit shortens the current iteration step length, for example, halves its value, and returns to step S2 to recalculate the roll-over angle increment, the target tension value and the winch speed instruction.

[0089] By comparing the synchronization reliability coefficient with the threshold, real-time monitoring and dynamic adjustment of the synchronization of the roll-over process are realized. This feedback mechanism can quickly shorten the iteration step length when the synchronization decreases, increase the update frequency of the control instruction, thereby ensuring the smooth transition of the thruster attitude and the stable control of the front and rear sling tensions, and improving the adaptability and reliability of the system.

[0090] Step S3 is closely related to steps S2 and S4. The winch speed instruction generated in step S2 is monitored and evaluated in real time by step S3 to ensure the synchronization of the thruster roll-over process. Step S3 generates a synchronization reliability coefficient by calculating the curvature acceleration difference and the tension phase drift, and adjusts the iteration step length and returns to step S2 to recalculate the control parameters when the synchronization is insufficient, forming a dynamic feedback loop to ensure the real-time and stability of the control system. At the same time, the execution result of step S3 provides support for step S4, and step S4 constructs a safety margin map by comparing the flow rate monitoring data and the thruster vibration spectrum to further evaluate the safety of the roll-over process, and also shortens the iteration step length and returns to step S2 for predictive correction when necessary.

[0091] Since relying solely on angle and tension control cannot fully evaluate the real-time effects of environmental factors, especially the safety risks caused by changes in flow rate and superposition of thruster vibration. Therefore, step S4 introduces flow rate monitoring data and thruster vibration spectrum to construct a safety margin map to quantify risks and trigger iteration step length adjustment when necessary, thereby forming a closed loop with the predictive correction of step S2 to ensure the safety and stability of the operation.

[0092] Step S4 includes the following contents:

[0093] S4-1, data acquisition:

[0094] The control unit first collects the flow velocity in the hoisting area in real time through the flow sensor, generating flow rate monitoring data. The flow rate monitoring data reflects the dynamic changes of the tidal current in the working environment, and is an important basis for evaluating the influence of the environment on the propeller turning. At the same time, the vibration sensor installed on the propeller collects the vibration signal of the propeller, and performs frequency domain analysis on the vibration signal to generate a vibration spectrum. The vibration spectrum describes the vibration intensity of the propeller at different frequencies, which is used to quantify the vibration characteristics of the propeller during turning. The purpose of collecting flow rate monitoring data and vibration spectrum is to comprehensively monitor the environment and equipment state, and to provide real-time input for subsequent safety evaluation.

[0095] S4-2, constructing a safety margin chart:

[0096] The control unit constructs a safety margin chart using the flow rate monitoring data and the vibration spectrum. The safety margin chart is a chart with time as the horizontal axis and safety margin value as the vertical axis. The safety margin value is a dimensionless value used to comprehensively evaluate the safety status of the current operation. The calculation of the safety margin value combines the effects of flow rate and vibration: first, calculate the flow rate term by comparing the real-time flow rate monitoring data with the preset safety flow rate threshold to obtain the flow rate margin ratio; the safety flow rate threshold is the upper limit of the flow rate calibrated according to the working environment and the propeller tolerance. Secondly, calculate the vibration term by comparing the real-time vibration spectrum of the propeller with the reference vibration spectrum in a specific frequency range to obtain the relative deviation of the vibration; the reference vibration spectrum is the reference vibration level calibrated in the undisturbed ideal state. Finally, multiply the flow rate term and the vibration term to obtain the safety margin value. The closer the safety margin value is to 1, the safer the operation is; when the safety margin value decreases, it indicates that the flow rate or vibration is close to the dangerous level.

[0097] The calculation of the safety margin value is determined by multiplying the flow rate term and the vibration term, which has sufficient theoretical basis and practical significance, because this method comprehensively considers the double risks of environmental disturbance and equipment dynamic response in the turning and lifting operation of the underwater propeller. The flow rate term quantifies the threat degree of tidal disturbance to the lifting operation by calculating the proportion of the excess of the real-time flow rate monitoring data to the safe flow rate threshold; when the flow rate approaches or exceeds the safe threshold, the flow rate term tends to zero, reflecting the intensification of environmental risk. The vibration term assesses the dynamic stability of the propeller during the turning process by comparing the energy deviation of the propeller vibration spectrum and the reference vibration spectrum; when the vibration energy significantly exceeds the benchmark, the vibration term decreases, indicating that the equipment may face the risk of instability or fatigue. The multiplication of the two forms the safety margin value, which can effectively capture the comprehensive risk under the interaction of flow rate and vibration, for example, high flow rate may amplify the negative effects of vibration, and abnormal vibration may trigger structural resonance at a certain flow rate. This product form is based on the engineering principle of risk superposition, ensuring that the safety margin value quickly decreases when either factor exceeds the limit, triggering control adjustment, while maintaining a high value when both are safe, reflecting the stability of the operation. Experimental calibration and mechanical analysis further verify the reliability of this method, making it a scientific basis for evaluating the safety of the operation.

[0098] The construction of the safety margin diagram quantifies the influence of flow rate and vibration into a single safety indicator, facilitating the control unit to quickly determine the safety state of the operation. It can consider both environmental and equipment factors to ensure the control unit's comprehensive perception of potential risks, thereby providing reliable safety protection for the turning and lifting operation of the propeller.

[0099] S4-3, warning area identification:

[0100] The control unit continuously monitors the safety margin value in the safety margin diagram and compares it with the preset warning threshold. The warning threshold is a pre-calibrated lower limit of safety, for example 0.2, used to define the warning area in the safety margin diagram. When the safety margin value is lower than the warning threshold, it indicates that the current operation state has entered the warning area, meaning that the flow rate or vibration has approached a dangerous level, which may pose a threat to the safety of the propeller turning process.

[0101] By setting the warning threshold and identifying the warning area, the control unit can timely discover potential safety hazards. This early warning mechanism ensures that the control unit can take measures before the risk intensifies, thereby effectively preventing accidents during the propeller turning process and improving the safety and reliability of the operation.

[0102] S4-3, iterative step adjustment:

[0103] The control unit dynamically adjusts the iteration step length according to the monitoring result of the safety margin map, and forms a feedback closed loop with step S2. If the safety margin value is greater than or equal to the warning threshold, it indicates that the operation state is safe, and the control unit keeps the current iteration step length unchanged and continues to execute the existing control process. The iteration step length is provided by the iteration step length table generated in step S1. If the safety margin value is lower than the warning threshold, it indicates that it enters the warning area, and the control unit shortens the current iteration step length, for example, halves it, to increase the update frequency of the control command and slow down the response of the turning motion to the environmental disturbance. The adjusted iteration step length is written into the iteration step length table of the control unit, and the control unit re-executes step S2 according to the updated iteration step length table and real-time tension value, that is, calculates the next turning angle increment, target tension value using the least square prediction method, and generates new winch speed command.

[0104] Step S4 has a close technical relationship with steps S1, S2 and S5. The iteration step length table generated in step S1 provides the initial calculation step length for step S4, which adjusts the iteration step length when the safety margin is insufficient, and passes the adjusted iteration step length to step S2 to trigger the recalculation of the control command, forming a dynamic feedback closed loop between environmental disturbance and control command. At the same time, step S4 provides a safety premise for the synchronous lifting command of step S5 through the monitoring result of the safety margin map, ensuring that the turning operation is completed when the safety margin remains positive.

[0105] The foregoing steps S1 to S4 realize dynamic control and safety monitoring of the turning process by collecting the turning angle sequence and the sling tension sequence, generating the iteration step length table, and combining the least square prediction method, the synchronization reliability coefficient and the safety margin map. These steps ensure the coordination of the thruster turning angle and the sling tension through real-time adjustment of the iteration step length and the winch speed command, and continuously evaluate the environmental disturbance and equipment vibration. However, real-time adjustment and monitoring alone are not enough to ensure the final stability and safety of the entire turning process, especially in unstable tidal flow and low visibility water environments, the turning operation can only be safely completed when certain conditions are met. Step S5, as the end of the entire process, is responsible for judging whether the turning process has reached a safe and stable state, and completing the turning when the conditions are met, while archiving the operation data to support subsequent optimization.

[0106] Step S5 includes the following:

[0107] S5-1, monitor the synchronization reliability coefficient and the safety margin map:

[0108] The control unit monitors the synchronous reliability coefficient and the safety margin chart in real time by continuously collecting and analyzing data to evaluate the synchronization and safety of the propeller turning-over process. In each cycle period, the control unit calculates the continuous change amplitude of the synchronous reliability coefficient and determines whether it is always less than or equal to the preset fluctuation amplitude threshold within a preset number of continuous cycles to confirm the stability of the synchronous reliability coefficient. At the same time, the control unit checks whether the values in the safety margin chart are always positive within the same number of continuous cycles to verify the safety status of the operation. Only when the fluctuation amplitude of the synchronous reliability coefficient meets the stability condition and the values in the safety margin chart remain positive, the control unit confirms that the propeller turning-over process is in a safe and stable state, otherwise it continues to monitor or returns to the previous step to adjust.

[0109] Through real-time monitoring of the synchronous reliability coefficient and the safety margin chart, the control unit can fully grasp the dynamic performance of the propeller turning-over process and ensure that the synchronization and safety meet the expected requirements under complex environments.

[0110] S5-2, determine the turning-over completion condition:

[0111] The control unit evaluates the stability of the synchronous reliability coefficient and the positive value state of the values in the safety margin chart in each cycle period to determine whether the propeller turning-over process meets the completion requirements. The judgment process first checks the change amplitude of the synchronous reliability coefficient within a preset number of continuous cycles by calculating the difference between the maximum value and the minimum value and comparing it with the preset fluctuation amplitude threshold. If the difference is less than or equal to the threshold, the synchronous reliability coefficient is considered stable. Secondly, it checks whether the values in the safety margin chart are all positive within the same number of continuous cycles by comparing each cycle value with zero to ensure that all values are greater than zero. Only when the stability condition of the synchronous reliability coefficient and the positive value condition of the safety margin chart are met simultaneously within a continuous preset number of cycles, the control unit determines that the propeller turning-over process has reached a safe and stable state and enters the subsequent process. If either condition is not met, it returns to step S3 to adjust the synchronization of the turning angle sequence and the sling tension sequence, or returns to step S4 to correct the matching degree of the flow rate monitoring data and the vibration spectrum, until the conditions are met.

[0112] The control unit can accurately determine the completion time of the propeller turning-over process by using the dual condition verification of the stability of the synchronous reliability coefficient and the positive value of the safety margin chart, ensuring that the operation is performed when both synchronization and safety meet the requirements. This judgment mechanism reduces the risk of misjudgment and improves the accuracy and safety of the propeller turning-over hoisting operation through multi-dimensional data confirmation.

[0113] S5-3, issue a synchronous lifting instruction:

[0114] When the stability of the synchronization reliability coefficient and the positive value state of the safety margin diagram simultaneously meet the preset continuous cycle number, the control unit generates and issues a synchronous lifting instruction to coordinate the action of the winch to complete the turning over and lifting operation of the propeller. The synchronous lifting instruction is based on the next turning angle increment and the target tension value predicted in step S2, and determines the specific instruction content by calculating the tension adjustment amount required by each sling in the next cycle and the winding and unwinding speed of the winch. The instruction includes a winch speed instruction calculated by the relationship between the turning angle increment and time, and a tension distribution parameter determined according to the distribution ratio of the target tension value among the slings. The control unit sends these instructions to the winch to guide it to adjust the winding and unwinding speed of each sling, so that the propeller smoothly lifts to the target position after the turning over is completed, ensuring the coordination and stability of the whole process.

[0115] By generating and issuing the synchronous lifting instruction, the control unit realizes accurate control of the winch, ensuring that the propeller smoothly lifts to the target position after the turning over is completed. This instruction generation and execution mechanism ensures the synchronization and stability of the action through pre-calculation and real-time coordination, improving the execution efficiency and safety of the propeller turning over and hoisting operation.

[0116] S5-4, data archiving:

[0117] After the propeller turning over process is completed, the control unit stores the relevant data into the storage unit to support subsequent analysis and optimization. The stored data includes the turning angle sequence, the sling tension sequence and the iteration step table. The turning angle sequence records the angle change of the propeller at each time point during the turning over process, in radians, and is generated by the calculation results of steps S2 and S3; the sling tension sequence records the tension change of the front and rear slings at each time point, and is formed by the monitoring data of step S3; the iteration step table records the iteration step of each time section, which comes from the adjustment process of steps S3 and S4. The control unit organizes these data in time stamp alignment, ensuring that the correspondence of each group of data is clear and traceable, and forms a high-resolution working condition archive after being stored in the storage unit, which is used for reference and performance evaluation of subsequent hoisting operations.

[0118] Step S5 directly uses the synchronization reliability coefficient provided by step S3 and the safety margin value provided by step S4 to determine the turning over completion time through stability and positive value judgment, ensuring that the synchronization and safety requirements are met. At the same time, the synchronous lifting instruction generated by step S5 relies on the turning angle increment and the target tension value predicted by step S2, and the archived data provides a reference for the optimization of the initial conditions of step S1. This front and back linked technical process ensures the stability, safety and continuity of the propeller turning over and hoisting operation through data transfer and verification, meeting the high standard requirements of the operation in complex environments.

[0119] The above formulas are all de-dimensioned to calculate the numerical values, the formulas are obtained by collecting a large amount of data to simulate a formula of the most recent real situation, and the preset parameters in the formulas are set by the person skilled in the art according to the actual situation.

[0120] It should be noted that the system of the present application can be deployed in the device itself to realize embedded application, or can be run on PC or other terminal with user interface, so as to meet various hardware environments and use requirements.

[0121] The above only describes some exemplary embodiments of the present application by way of illustration, and it is needless to say that the described embodiments can be modified in various ways without departing from the spirit and scope of the present application for those skilled in the art. Therefore, the above figures and descriptions are illustrative in nature and should not be understood as limiting the scope of protection of the claims of the present application.

[0122] It should be noted that in this document, relational terms such as first and second and the like can merely be used to distinguish one entity or action from another, without necessarily requiring or implying any actual such relationship or order between or among the entities or actions. Also, the terms "comprises", "comprising", or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by "comprises... a" does not, without more constraints, exclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the element.

[0123] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto, any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A multi-parameter cooperative control method for the turning and lifting of an underwater thruster, characterized in that, The method comprises the steps of: S1: Collecting the sequence of turning angle and the sequence of sling tension, performing second-order difference calculation of instantaneous curvature, and refining the time interval of high curvature section according to the bisection principle to generate an iteration step table and write it into the control unit; Step S1 includes the following contents: Collecting the turning angle and tension data with a fixed initial time interval by using the sensor, calculating the instantaneous curvature by the second-order difference method, identifying the high curvature section according to the curvature threshold, halving the time interval of the high curvature section to increase the data collection frequency, generating an iteration step table recording the time interval of each section, and transmitting the iteration step table, the sequence of turning angle and the sequence of tension to the control unit; S2: The control unit reads the iteration step table and the real-time tension value, calculates the next turning angle increment and target tension value by using the least square prediction method, and sends the winch speed instruction; Step S2 includes the following contents: The control unit extracts the step length value of the current time section from the iteration step table as the current time step, calculates the turning angle increment and target tension value of the thruster at the next time based on the historical turning angle sequence and the historical tension sequence by using the least square prediction method, calculates the winch speed according to the turning angle increment and the target tension value by using the mechanical model, and sends the winch speed as an instruction to the winch to adjust the speed of the sling; S3: During the execution of the winch speed instruction by the winch, first, the curvature acceleration difference value is obtained according to the angular velocity curve and the time derivative of the angular velocity curve, then the phase drift amount of the tension of the front and rear slings is calculated by using the cross spectrum analysis, and the two are input into a preset segmented mapping table to output a synchronous reliability coefficient, if the synchronous reliability coefficient is lower than a preset threshold, the current iteration step is shortened and the winch speed instruction is refreshed in step S2; Step S3 includes the following contents: During the execution of the winch speed instruction by the winch, the control unit monitors the turning angle and tension data in real time, calculates the angular velocity and angular acceleration by differentiating the turning angle sequence, and compares them with the reference angular acceleration to obtain the curvature acceleration difference value; the phase drift amount of the tension signals of the front and rear slings is calculated by using the cross spectrum analysis method; the curvature acceleration difference value and the tension phase drift amount are input into a preset segmented mapping table to generate a synchronous reliability coefficient; S4: The control unit continuously compares the flow rate monitoring data and the thruster vibration spectrum to construct a safety margin diagram, if the safety margin diagram enters a warning area, the iteration step is also shortened and the prediction correction is performed in step S2; S5: When the synchronous reliability coefficient is stable and the safety margin diagram remains positive in the continuous loop, the control unit issues a synchronous lifting instruction to complete the turning.

2. The multi-parameter coordinated control method for the turning and lifting of the underwater thruster of claim 1, wherein, Step S4 includes the following contents: The control unit collects the flow rate monitoring data in the hoisting area in real time through the flow sensor, and generates a vibration spectrum by performing frequency domain analysis on the vibration signals collected by the vibration sensor on the thruster, and constructs a safety margin diagram using the flow rate monitoring data and the vibration spectrum, when the safety margin value is lower than the preset warning threshold, the current iteration step is shortened and step S2 is triggered to generate a new winch speed instruction.

3. The multi-parameter coordinated control method for the turning and hoisting of the underwater thruster of claim 2, characterized in that, Step S4 further includes the following contents: The safety margin diagram takes time as the horizontal axis and safety margin value as the vertical axis, and is determined by calculating the product of the flow rate term ratio and the vibration term.

4. The multi-parameter coordinated control method for the turning and hoisting of the underwater thruster of claim 3, characterized in that, Step S5 includes the following contents: The control unit continuously monitors the generated synchronization reliability coefficient and the safety margin graph, and judges that the synchronization reliability coefficient remains stable in a predetermined continuous period and the safety margin graph maintains a positive value in a predetermined continuous period.

5. The multi-parameter coordinated control method for the turning and hoisting of the underwater thruster of claim 4, characterized in that, Step S5 further includes the following contents: When the conditions that the synchronization reliability coefficient remains stable and the safety margin graph maintains a positive value are both met, the control unit issues a synchronization promotion command to complete the flipping operation, and then archives the data storage.

Images