Minimum bending radius multi-point turning action control method and system

Abstract

The invention relates to a minimum bending radius multi-point turning action control method and system, and relates to the technical field of submarine cable laying, and the method comprises the steps: obtaining cable parameters of a cable, cable laying ship parameters of a cable laying ship, and marine environment parameters; analyzing the cable parameters, the cable laying ship parameters and the marine environment parameters to generate a predicted bending radius; analyzing the cable parameters to determine the minimum bending radius; judging whether the predicted bending radius meets the requirement of the minimum bending radius or not; if yes, the cable parameters of the cable, the cable laying ship parameters of the cable laying ship and the marine environment parameters are continuously obtained for cyclic judgment; if not, analyzing the predicted bending radius and the minimum bending radius to generate a bending radius error; analyzing the bending radius error to generate a speed adjustment amount; and the cable laying ship is adjusted according to the speed adjustment amount so that the predicted bending radius can meet the requirement of the minimum bending radius. The method has the effect of improving the timeliness of adjusting the bending radius.

Description

Technical Field

[0001] This application relates to the technical field of submarine cable laying, and in particular to a method and system for controlling the multi-point turning motion with the minimum bending radius. Background Art

[0002] A submarine cable is a cable laid on the seabed for telecommunication transmission. It can transmit telephone, Internet data, and other forms of data. The minimum bending radius of a submarine cable is a key parameter, which ensures that the cable will not be damaged due to excessive bending during laying and operation.

[0003] In the related art, during the laying of submarine cables, bending sensors or fiber optic strain sensors are arranged along the cable to monitor the bending radius of the cable in real time. Once it is determined that the bending radius of the cable is lower than the minimum bending radius of the cable, the system calculates the speed of the cable laying ship in real time according to the PID algorithm, and adjusts the cable laying ship according to the calculated speed to make the bending radius of the cable.

[0004] In view of the above related art, when it is determined that the bending radius of the cable is lower than the minimum bending radius of the cable, the speed of the cable laying ship is adjusted to improve the bending radius of the cable. During this period, the bending radius of the cable has reached a level that is harmful to the cable, resulting in low timeliness of the bending radius adjustment and room for improvement. Summary of the Invention

[0005] In order to improve the timeliness of the bending radius adjustment, this application provides a method and system for controlling the multi-point turning motion with the minimum bending radius.

[0006] In a first aspect, this application provides a method for controlling the multi-point turning motion with the minimum bending radius, adopting the following technical solutions:

[0007] The method for controlling the multi-point turning motion with the minimum bending radius includes:

[0008] Obtain the cable parameters of the preset cable, the cable laying ship parameters of the preset cable laying ship, and the marine environment parameters;

[0009] Analyze the cable parameters, the cable laying ship parameters, and the marine environment parameters to generate a predicted bending radius;

[0010] Analyze the cable parameters to determine the minimum bending radius;

[0011] Judge whether the predicted bending radius meets the requirement of the minimum bending radius;

[0012] If it meets the requirement, continue to obtain the cable parameters of the cable, the cable laying ship parameters of the cable laying ship, and the marine environment parameters for cyclic judgment;

[0013] If not, analyze the predicted bending radius and the minimum bending radius to generate a bending radius error;

[0014] Analyze the bending radius error to generate a speed adjustment amount;

[0015] Adjust the cable laying vessel according to the speed adjustment amount so that the predicted bending radius meets the requirements of the minimum bending radius.

[0016] By adopting the above technical solution, detect and call the cable parameters, cable laying vessel parameters and marine environment parameters, so as to determine the predicted bending radius after analyzing the cable parameters, cable laying vessel parameters and marine environment parameters. When it is determined that the predicted bending radius is less than the minimum bending radius, analyze the bending radius error to determine the speed adjustment amount, and control the cable laying vessel to make adjustments in advance with the speed adjustment amount, so as to prevent the bending radius of the cable from being damaged, and further improve the timeliness of adjusting the bending radius.

[0017] Optionally, the steps of analyzing the cable parameters, cable laying vessel parameters and marine environment parameters to generate a predicted bending radius include:

[0018] Analyze the cable parameters to generate a static cable tension;

[0019] Analyze the static cable tension, cable parameters, cable laying vessel parameters and marine environment parameters to generate a dynamic cable tension;

[0020] Analyze the dynamic cable tension and cable parameters to generate a predicted bending radius.

[0021] By adopting the above technical solution, after analyzing the static cable tension, cable parameters, cable laying vessel parameters and marine environment parameters, determine the dynamic cable tension, and determine the predicted bending radius according to the dynamic cable tension and cable parameters, so as to take into account the influence of the marine environment on the bending radius of the cable, and further improve the accuracy of the predicted bending radius.

[0022] Optionally, the steps of analyzing the cable parameters to generate a static cable tension include:

[0023] Analyze the cable parameters to determine the unit cable weight;

[0024] Analyze the unit cable weight and the minimum bending radius to generate a basic static tension;

[0025] Analyze the basic static tension and a preset tension margin to generate a static cable tension.

[0026] By adopting the above technical solution, after analyzing the weight per unit length of the cable and the minimum bending radius, the basic static tension is determined, so as to ensure that the bending radius of the cable is not less than the minimum bending radius under the state of the basic static tension, and a tension margin is added to the basic static tension, thereby improving the accuracy of the cable static tension.

[0027] Optionally, the steps of analyzing the cable static tension, cable parameters, cable laying ship parameters and marine environment parameters to generate the cable dynamic tension include:

[0028] Analyze the cable parameters, cable laying ship parameters and marine environment parameters to generate a cable tension adjustment amount;

[0029] Analyze the cable static tension and the cable tension adjustment amount to generate the cable dynamic tension.

[0030] By adopting the above technical solution, after analyzing the cable parameters, cable laying ship parameters and marine environment parameters, the cable tension adjustment amount caused by the marine environment and the cable laying ship on the cable is determined, so that the cable tension adjustment amount is added to the basis of the cable static tension to determine the cable dynamic tension, thereby improving the accuracy of the cable dynamic tension.

[0031] Optionally, the steps of analyzing the cable parameters, cable laying ship parameters and marine environment parameters to generate a cable tension adjustment amount include:

[0032] Analyze the cable parameters to determine the cable cross-sectional area and the real-time length of the cable;

[0033] Analyze the cable laying ship parameters to determine the cable laying ship speed;

[0034] Analyze the marine environment parameters and the cable laying ship parameters to determine the seawater density, seawater resistance coefficient and real-time sea current speed;

[0035] Analyze the marine environment parameters to generate the sea current speed field gradient;

[0036] Analyze the seawater density, seawater resistance coefficient, cable cross-sectional area, real-time sea current speed, cable laying ship speed, sea current speed field gradient and real-time length of the cable to generate a cable tension adjustment amount.

[0037] By adopting the above technical solution, according to the influence of the cable laying ship speed and the real-time sea current speed on the cable tension, and simulating the tension influence of the sea current and the cable laying ship on the entire cable according to the sea current speed field gradient, the cable tension adjustment amount is calculated, thereby improving the accuracy of the cable tension adjustment amount.

[0038] Optionally, the steps of analyzing the cable dynamic tension and cable parameters to generate a predicted bending radius include:

[0039] Analyze the unit cable weight and the cable dynamic tension to generate catenary constants;

[0040] Obtain the calculated radius arc length;

[0041] Analyze the cable dynamic tension, the unit cable weight, the calculated radius arc length, and the catenary constants to generate a basic predicted radius;

[0042] Analyze the catenary constants, the calculated radius arc length, and the cable parameters to generate a corrected bending radius;

[0043] Analyze the basic predicted radius and the corrected bending radius to generate a predicted bending radius.

[0044] By adopting the above technical solution, the cable is regarded as a catenary shape, thereby calculating the basic predicted radius, and calculating the corrected bending radius according to the mutual influence between cables. After summing the basic predicted radius and the corrected bending radius, the predicted bending radius is obtained, thereby improving the accuracy of the predicted bending radius.

[0045] Optionally, the step of analyzing the catenary constants, the calculated radius arc length, and the cable parameters to generate a corrected bending radius includes:

[0046] Analyze the cable parameters to generate a contact force density function;

[0047] Analyze the calculated radius arc length and the contact force density function to generate a unit contact force density;

[0048] Analyze the unit cable weight, the unit contact force density, the calculated radius arc length, and the catenary constants to generate a corrected bending radius.

[0049] By adopting the above technical solution, calculate the calculated radius arc length according to the contact force density function to determine the unit contact force density, thereby determining the influence of the contact force between different strands of the cable itself, and calculating the corrected bending radius after calculating the unit cable weight, the unit contact force density, the calculated radius arc length, and the catenary constants, thereby improving the accuracy and efficiency of determining the corrected bending radius.

[0050] Optionally, the step of analyzing the cable parameters to generate a contact force density function includes:

[0051] Analyze the cable parameters to generate a normal stiffness coefficient, a tangential stiffness coefficient, a normal damping coefficient, and a tangential damping coefficient;

[0052] Establish a discrete particle model according to the cable parameters;

[0053] Contact detection is performed according to the discrete particle model to determine the contact pair particles and the corresponding normal overlap, tangential relative displacement, normal relative velocity, and tangential relative velocity;

[0054] The normal stiffness coefficient and the normal overlap are analyzed to generate the normal contact force;

[0055] The tangential stiffness coefficient and the tangential relative displacement are analyzed to generate the tangential contact force;

[0056] The normal damping coefficient, the normal relative velocity, the tangential damping coefficient, and the tangential relative velocity are analyzed to generate the damping contact force;

[0057] The normal contact force, the tangential contact force, and the damping contact force are analyzed to generate the total particle contact force;

[0058] The total particle contact force and the preset arc length step are analyzed to generate the contact force density function.

[0059] By adopting the above technical solution, the contact between different strands of the cable is simulated according to the discrete particle model, so as to determine the normal overlap, tangential relative displacement, normal relative velocity, and tangential relative velocity, and successively calculate the normal contact force, tangential contact force, and damping contact force. After synthesis, the total particle contact force is obtained, and then the total particle contact force is mapped along the arc length step, so as to obtain the contact force density function, thereby improving the accuracy of the contact force density function.

[0060] In a second aspect, the present application provides a minimum bending radius multi-point turning motion control system, adopting the following technical solution:

[0061] A minimum bending radius multi-point turning motion control system, comprising:

[0062] An acquisition module, configured to acquire cable parameters, cable laying ship parameters, and ocean environment parameters;

[0063] A memory, configured to store a program of the minimum bending radius multi-point turning motion control method as described in any one of the above;

[0064] A processor, the program in the memory can be loaded and executed by the processor and implement the minimum bending radius multi-point turning motion control method as described in any one of the above.

[0065] By adopting the above technical solution, the processor loads and executes the program of the minimum bending radius multi-point turning motion control method stored in the memory, controls the acquisition module to acquire a series of data related to the minimum bending radius multi-point turning motion control, so as to detect and call the cable parameters, cable laying ship parameters and marine environment parameters, and then analyze the cable parameters, cable laying ship parameters and marine environment parameters to determine the predicted bending radius. When it is determined that the predicted bending radius is less than the minimum bending radius, the bending radius error is analyzed to determine the speed adjustment amount, and the cable laying ship is controlled to make adjustments in advance with the speed adjustment amount, so as to prevent the bending radius of the cable from being damaged, and further improve the timeliness of the bending radius adjustment.

[0066] In summary, the present application includes at least one of the following beneficial technical effects:

[0067] 1. By detecting and calling the cable parameters, cable laying ship parameters and marine environment parameters, analyzing the cable parameters, cable laying ship parameters and marine environment parameters to determine the predicted bending radius, and when it is determined that the predicted bending radius is less than the minimum bending radius, analyzing the bending radius error to determine the speed adjustment amount, and controlling the cable laying ship to make adjustments in advance with the speed adjustment amount, so as to prevent the bending radius of the cable from being damaged, and further improve the timeliness of the bending radius adjustment;

[0068] 2. By analyzing the cable static tension, cable parameters, cable laying ship parameters and marine environment parameters, determining the cable dynamic tension, and determining the predicted bending radius according to the cable dynamic tension and cable parameters, so as to take into account the influence of the marine environment on the cable bending radius, and further improve the accuracy of the predicted bending radius;

[0069] 3. By regarding the cable as a catenary shape, calculating the basic predicted radius, calculating the corrected bending radius according to the mutual influence between the cables, and summing the basic predicted radius and the corrected bending radius to obtain the predicted bending radius, thereby improving the accuracy of the predicted bending radius. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] Figure 1 is a flowchart of the minimum bending radius multi-point turning motion control method in an embodiment of the present application.

[0071] Figure 2 is a flowchart of the steps of analyzing the cable parameters, cable laying ship parameters and marine environment parameters to generate a predicted bending radius in an embodiment of the present application.

[0072] Figure 3 is a flowchart of the steps of analyzing the cable parameters to generate the cable static tension in an embodiment of the present application.

[0073] Figure 4It is a flowchart of the steps in the embodiment of the present application for analyzing the static tension of the cable, cable parameters, cable laying ship parameters, and marine environment parameters to generate the dynamic tension of the cable.

[0074] Figure 5 It is a flowchart of the steps in the embodiment of the present application for analyzing the cable parameters, cable laying ship parameters, and marine environment parameters to generate the cable tension adjustment amount.

[0075] Figure 6 It is a flowchart of the steps in the embodiment of the present application for analyzing the dynamic tension of the cable and cable parameters to generate the predicted bending radius.

[0076] Figure 7 It is a flowchart of the steps in the embodiment of the present application for analyzing the catenary constant, calculated radius arc length, and cable parameters to generate the corrected bending radius.

[0077] Figure 8 It is a flowchart of the steps in the embodiment of the present application for analyzing the cable parameters to generate the contact force density function. Detailed implementation manners

[0078] In order to make the objectives, technical solutions, and advantages of the present application clearer, the following further describes the present application in detail with reference to the appended Figures 1 to 8 drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0079] The embodiment of the present application discloses a control method for multi-point turning actions with a minimum bending radius, specifically discloses a processing terminal and related sensors. The processing terminal is communicatively connected to the related sensors to achieve data interaction and control. After the related sensors detect the cable parameters, cable laying ship parameters, and marine environment parameters and send them to the processing terminal, the processing terminal analyzes the cable parameters, cable laying ship parameters, and marine environment parameters to determine the predicted bending radius, and compares the predicted bending radius with the minimum bending radius. When it is determined that the predicted bending radius is less than the minimum bending radius, the bending radius error is determined after analyzing the predicted bending radius and the minimum bending radius, and then the speed adjustment amount is determined after analyzing the bending radius error. Thus, the speed of the cable laying ship is adjusted according to the speed adjustment amount to ensure that the bending radius of the cable is always greater than the minimum bending radius, thereby improving the timeliness of the bending radius adjustment.

[0080] Referring to Figure 1 , the embodiment of the present application discloses a control method for multi-point turning actions with a minimum bending radius, including the following steps:

[0081] Step S100: Obtain the cable parameters of the preset cable, the cable laying ship parameters of the preset cable laying ship, and the marine environment parameters.

[0082] Among them, the cable refers to the cable laid under the sea, and the specific model and parameters are determined by the operator according to the actual situation. The cable-laying ship refers to the ship used to carry the cable and bury the cable under the sea.

[0083] Cable parameters refer to the parameters related to the cable, including the structure of the cable, such as a multi-layer twisted structure, and also include diameter, mass, elastic modulus, Poisson's ratio, weight per unit length, minimum bending radius, cable cross-sectional area, and real-time cable length, etc. Some of these parameters are input by the operator and stored in the processing terminal, and some are detected by sensors and sent to the processing terminal.

[0084] Cable-laying ship parameters refer to the relevant parameters of the cable-laying ship, including the speed of the cable-laying ship, etc., which are detected by a speed sensor and sent to the processing terminal.

[0085] Marine environment parameters refer to the relevant parameters of the marine environment for cable laying, including parameters such as sea current speed, seawater density, and seawater drag coefficient, which are detected by a flow velocity sensor and sent to the processing terminal.

[0086] Step S101: Analyze the cable parameters, cable-laying ship parameters, and marine environment parameters to generate a predicted bending radius.

[0087] Among them, the predicted bending radius refers to the bending radius of the cable speculated and calculated based on the ship speed of the cable-laying ship and subsequent marine environment parameters, which is determined by the processing terminal after analyzing the cable parameters, cable-laying ship parameters, and marine environment parameters. The specific method refers to Figure 2 the steps.

[0088] Step S102: Analyze the cable parameters to determine the minimum bending radius.

[0089] Among them, the minimum bending radius refers to the minimum bending radius when the cable is in a safe state. The specific value is determined according to different cables and is identified and called by the processing terminal in the cable parameters.

[0090] Step S103: Judge whether the predicted bending radius meets the requirements of the minimum bending radius.

[0091] Among them, the requirement of the minimum bending radius means not less than the minimum bending radius. The processing terminal judges whether the predicted bending radius is not less than the minimum bending radius, so as to determine whether the bending radius of the cable may be in a damaged state during the subsequent cable laying process.

[0092] Step S1031: If it meets the requirements, continue to obtain the cable parameters of the cable, the cable-laying ship parameters of the cable-laying ship, and the marine environment parameters for cyclic judgment.

[0093] Among them, if the processing terminal determines that the predicted bending radius is not less than the minimum bending radius, it indicates that during the subsequent cable laying process, the bending radius of the cable will not be in a damaged state. Therefore, the cable parameters of the cable, the cable laying ship parameters of the cable laying ship, and the marine environment parameters are continuously detected and called, so as to continuously monitor the influence and change of the cable laying ship and the marine environment on the cable bending radius.

[0094] Step S1032: If not, analyze the predicted bending radius and the minimum bending radius to generate a bending radius error.

[0095] Among them, if the processing terminal determines that the predicted bending radius is less than the minimum bending radius, it indicates that during the subsequent cable laying process, the bending radius of the cable will be in a damaged state. Therefore, after analyzing the predicted bending radius and the minimum bending radius, a bending radius error is determined to provide data support for subsequent speed adjustment.

[0096] The bending radius error refers to the gap between the cable bending radius and the minimum bending radius, which is obtained by the processing terminal calculating the difference between the minimum bending radius and the predicted bending radius.

[0097] Step S104: Analyze the bending radius error to generate a speed adjustment amount.

[0098] Among them, the speed adjustment amount refers to the adjustment amount for adjusting the speed of the cable laying ship. The processing terminal calculates the bending radius error according to the PID algorithm, and after obtaining the proportional term, integral term, and differential term, they are added together to obtain the speed adjustment amount.

[0099] Step S105: Adjust the cable laying ship according to the speed adjustment amount so that the predicted bending radius meets the requirements of the minimum bending radius.

[0100] Among them, after the processing terminal determines the speed adjustment amount, the processing terminal controls the cable laying ship to adjust the ship speed corresponding to the speed adjustment amount. Thus, after the cable is laid to the corresponding marine environment, the cable laying ship has made adjustments in advance to ensure that the bending radius of the cable is always greater than the minimum bending radius and the cable will not be in a damaged state.

[0101] Refer to Figure 2 , the steps of analyzing the cable parameters, the cable laying ship parameters, and the marine environment parameters to generate the predicted bending radius include:

[0102] Step S200: Analyze the cable parameters to generate the static cable tension.

[0103] Among them, the static cable tension refers to the tension of the cable in a safe state when it is not affected by the external environment, which is determined by the processing terminal analyzing and calculating the cable parameters. The specific method refers to Figure 3 the steps.

[0104] Step S201: Analyze the static cable tension, cable parameters, cable laying vessel parameters, and marine environment parameters to generate the dynamic cable tension.

[0105] Among them, the dynamic cable tension refers to the actual tension of the cable, which is determined by the processing terminal after analyzing the static cable tension, cable parameters, cable laying vessel parameters, and marine environment parameters. The specific method refers to Figure 4 the steps of

[0106] Step S202: Analyze the dynamic cable tension and cable parameters to generate the predicted bending radius.

[0107] Among them, the predicted bending radius in this step is the same as the predicted bending radius in step S101. The processing terminal regards the cable as a catenary model, thereby simulating the hanging shape of the cable from the ship to the seabed, and calculating the bending radius under the dynamic cable tension to obtain the predicted bending radius. The specific method refers to Figure 6 the steps of

[0108] Referring to Figure 3 , the steps of analyzing the cable parameters to generate the static cable tension include:

[0109] Step S300: Analyze the cable parameters to determine the unit cable weight.

[0110] Among them, the unit cable weight refers to the weight of the cable per unit length, which is identified and called by the processing terminal from the cable parameters.

[0111] Step S301: Analyze the unit cable weight and the minimum bending radius to generate the basic static tension.

[0112] Among them, the basic static tension refers to the ultimate static tension of the cable, which depends on the minimum bending radius of the cable. The processing terminal calculates the product of the unit cable weight and the minimum bending radius to obtain it.

[0113] Step S302: Analyze the basic static tension and the preset tension margin to generate the static cable tension.

[0114] Among them, the tension margin refers to the tension margin value that ensures that the bending radius of the cable without external influence will not be lower than the minimum bending radius. The specific value is determined by the operator according to the actual situation.

[0115] The static cable tension in this step is the same as the static cable tension in step S200, and is obtained by the processing terminal calculating the sum of the basic static tension and the tension margin.

[0116] Referring to Figure 4, the steps of analyzing the static cable tension, cable parameters, cable laying vessel parameters, and marine environment parameters to generate the dynamic cable tension include:

[0117] Step S400: Analyze the cable parameters, cable laying vessel parameters, and marine environment parameters to generate a cable tension adjustment amount.

[0118] Among them, the cable tension adjustment amount refers to the comprehensive influence amount of the cable laying vessel and the marine environment on the cable tension, which is determined by the processing terminal after analyzing the cable parameters, cable laying vessel parameters, and marine environment parameters. For the specific method, refer to Figure 5 the steps.

[0119] Step S401: Analyze the static cable tension and the cable tension adjustment amount to generate the dynamic cable tension.

[0120] Among them, the dynamic cable tension in this step is the same as the dynamic cable tension in Step S201, and is obtained by the processing terminal calculating the sum between the static cable tension and the cable tension adjustment amount.

[0121] Refer to Figure 5 , the steps of analyzing the cable parameters, cable laying vessel parameters, and marine environment parameters to generate a cable tension adjustment amount include:

[0122] Step S500: Analyze the cable parameters to determine the cable cross-sectional area and the real-time cable length.

[0123] Among them, the cable cross-sectional area refers to the cross-sectional area of the cable, and the real-time cable length refers to the length of the cable in seawater, which are identified and called by the processing terminal from the cable parameters.

[0124] Step S501: Analyze the cable laying vessel parameters to determine the cable laying vessel speed.

[0125] Among them, the cable laying vessel speed refers to the traveling speed of the cable laying vessel, which is identified and called by the processing terminal from the cable laying vessel parameters.

[0126] Step S502: Analyze the marine environment parameters and the cable laying vessel parameters to determine the seawater density, the seawater resistance coefficient, and the real-time sea current speed.

[0127] Among them, the seawater density refers to the density value of seawater, with a typical value of 1025 kg / m 3 , the seawater resistance coefficient refers to the resistance coefficient of seawater to the cable, which depends on the roughness of the cable surface and the Reynolds number, with a typical value of 0.8 to 1.2. The real-time sea current speed refers to the speed of the sea current, which is obtained by the processing terminal calculating the sea current speed in the direction opposite to the cable laying vessel speed from the total sea current speed. All three are identified and called by the processing terminal from the marine environment parameters.

[0128] Step S503: Analyze the marine environmental parameters to generate the gradient of the sea current velocity field.

[0129] Among them, the gradient of the sea current velocity field refers to the local velocity change rate reflecting the sea current velocity. First, the processing terminal obtains the components of the sea current in three-dimensional directions by solving the Navier-Stokes equation, and then on the discretized grid, the finite difference method or the finite volume method is used to approximately calculate the gradient of the velocity field.

[0130] Step S504: Analyze the seawater density, seawater resistance coefficient, cable cross-sectional area, real-time sea current velocity, cable laying ship velocity, gradient of the sea current velocity field, and real-time cable length to generate the cable tension adjustment amount.

[0131] Among them, the cable tension adjustment amount in this step is the same as the cable adjustment amount in Step S400, and is calculated by the processing terminal according to the seawater density, seawater resistance coefficient, cable cross-sectional area, real-time sea current velocity, cable laying ship velocity, gradient of the sea current velocity field, and real-time cable length. The specific calculation formula is:

[0132] ,

[0133] Among them, is the cable tension adjustment amount, is the seawater density, is the seawater resistance coefficient, is the cable cross-sectional area, is the real-time sea current velocity, is the cable laying ship velocity, is the gradient of the sea current velocity field, is the real-time cable length, is the infinitesimal along the cable length.

[0134] In an embodiment, the seawater density is 1025 kg / m 3 , the resistance coefficient is 1, the cable cross-sectional area is 0.00785 m 2 , the sea current velocity is 1.5 m / s, the ship speed is 1 m / s, the cable length is 100 m, and the distribution of the velocity field gradient along the cable length is as follows: from 0 to 20 meters, is 0.011 / m, from 20 to 80 meters, is 0.11 / m, and from 80 to 100 meters, is 0.051 / m. The cable tension adjustment amount It is 143.99 N.

[0135] Referring to Figure 6 , the steps for analyzing the dynamic cable tension and cable parameters to generate a predicted bending radius include:

[0136] Step S600: Analyze the unit cable weight and the dynamic cable tension to generate a catenary constant.

[0137] The catenary constant is a constant representing the geometric characteristics of the cable shape, obtained by the processing terminal calculating the quotient of the dynamic cable tension and the unit cable weight.

[0138] Step S601: Obtain the calculated radius arc length.

[0139] The calculated radius arc length is the arc length from the cable touchdown point to the calculation point, detected by the arc length sensor and sent to the processing terminal.

[0140] Step S602: Analyze the dynamic cable tension, the unit cable weight, the calculated radius arc length, and the catenary constant to generate a basic predicted radius.

[0141] The basic predicted radius is the bending radius calculated according to the catenary model, obtained by the processing terminal calculating based on the dynamic cable tension, the unit cable weight, the calculated radius arc length, and the catenary constant. The specific calculation formula is:

[0142] ,

[0143] Where is the basic predicted radius, is the dynamic cable tension, is the unit cable weight, is the calculated radius arc length, is the catenary constant.

[0144] Step S603: Analyze the catenary constant, the calculated radius arc length, and the cable parameters to generate a corrected bending radius.

[0145] The corrected bending radius is the bending radius affected by the contact force between the cable strands themselves, calculated by the processing terminal according to the catenary constant, the calculated radius arc length, and the cable parameters. The specific method refers to the steps in Figure 7 .

[0146] Step S604: Analyze the basic predicted radius and the corrected bending radius to generate a predicted bending radius.

[0147] Among them, the predicted bending radius in this step is the same as the predicted bending radius in step S202, and is obtained by the processing terminal calculating the sum of the basic predicted radius and the corrected bending radius.

[0148] Referring to Figure 7 , the steps of analyzing the catenary constant, the calculated radius arc length, and the cable parameters to generate the corrected bending radius include:

[0149] Step S700: Analyze the cable parameters to generate the contact force density function.

[0150] Among them, the contact force density function refers to the contact force mapped in the arc length direction, which is determined by the processing terminal according to the cable parameters after calculation. The specific method refers to Figure 8 the steps of.

[0151] Step S701: Analyze the calculated radius arc length and the contact force density function to generate the unit contact force density.

[0152] Among them, the unit contact force density refers to the contact force density at the calculated radius arc length, which is calculated by the processing terminal inputting the calculated radius arc length into the contact force density function. For example, if the calculated radius arc length is 10m and the total contact force of the contact force density function at the calculated radius arc length of 10m is 1000N, then the unit contact force density can be obtained by dividing the total contact force by the arc length step.

[0153] Step S702: Analyze the unit cable weight, the unit contact force density, the calculated radius arc length, and the catenary constant to generate the corrected bending radius.

[0154] Among them, the corrected bending radius in this step is the same as the corrected bending radius in step S603. The processing terminal first calculates the gradient in the arc length direction according to the unit contact force density and the calculated radius arc length, then calculates the quotient of the unit cable weight and the catenary constant, and takes the hyperbolic cosine function of the quotient. After calculating the quotient of the unit contact force density and the hyperbolic cosine function, multiply it by the reciprocal of the unit cable weight and the gradient to calculate the corrected bending radius.

[0155] In an embodiment, the unit cable weight is 10 kg / m, the calculated radius arc length is 10 m, the unit contact force density is 1000 N / m, the gradient in the arc length direction of the calculated radius arc length is 0.1, and the catenary constant is 50 m. Therefore, the finally calculated corrected bending radius is 81.9 m.

[0156] Referring to Figure 8 , the steps of analyzing the cable parameters to generate the contact force density function include:

[0157] Step S800: Analyze the cable parameters to generate the normal stiffness coefficient, tangential stiffness coefficient, normal damping coefficient, and tangential damping coefficient.

[0158] Among them, the normal stiffness coefficient refers to the stiffness coefficient in the normal direction of the cable, and the tangential stiffness coefficient refers to the stiffness coefficient in the tangential direction of the cable. According to Hertz contact theory, the equivalent elastic modulus is calculated based on the elastic modulus and Poisson's ratio in the cable parameters, and then the normal stiffness coefficient is calculated based on the equivalent elastic modulus, Poisson's ratio, and strand radius in the cable parameters. The tangential stiffness coefficient is obtained by multiplying the determined empirical constant by the normal stiffness coefficient.

[0159] The normal damping coefficient refers to the damping coefficient in the normal direction of the cable, and the tangential damping coefficient refers to the damping coefficient in the tangential direction of the cable. They are calculated by the processing terminal according to the Rayleigh damping model based on the cable weight, normal stiffness coefficient, and tangential stiffness coefficient.

[0160] Step S801: Establish a discrete particle model according to the cable parameters.

[0161] Among them, the discrete particle model is a particle model established according to the cable parameters. First, geometric modeling is carried out, and the cable structure in the cable parameters is decomposed into discrete particles, such as single-strand or multi-strand wires. Each particle has a diameter, mass, elastic modulus, and Poisson's ratio, and the spatial position and initial velocity of the particles are determined according to the specific velocity and structure in the cable parameters, such as a multi-layer twisted structure. Then, the parameter initialization is carried out, and the geometric model is given material parameters according to the calculated normal stiffness coefficient, tangential stiffness coefficient, normal damping coefficient, and tangential damping coefficient, so that the discrete particle model simulates a real cable.

[0162] Step S802: Perform contact detection according to the discrete particle model to determine the contact pair particles and the corresponding normal overlap, tangential relative displacement, normal relative velocity, and tangential relative velocity.

[0163] Among them, the contact pair particles refer to the particle pairs that come into contact during the simulation of the cable contact process. The cable contact is simulated by the discrete particle model, and through a spatial partitioning algorithm, such as an octree, it is quickly determined which particles come into contact, that is, the distance between the centers of the two particles is less than the sum of the radii.

[0164] The normal overlap refers to the overlap of the contact pair particles in the normal direction, which is obtained by identifying the center distance between the contact particles in the discrete model and then calculating the difference between the sum of the radii and the center distance.

[0165] The normal relative velocity refers to the velocity difference in the normal direction between particles, and the tangential relative velocity refers to the velocity difference in the tangential direction between particles. First, by identifying the change in the position of particles in the discrete particle model, then calculating the quotient of the position change and time to obtain the normal velocity, and then calculating the tangential component of the normal velocity to obtain the tangential velocity.

[0166] The tangential relative displacement refers to the tangential sliding distance between particles and is obtained by integrating the tangential relative velocity over time.

[0167] Step S803: Analyze the normal stiffness coefficient and the normal overlap amount to generate the normal contact force.

[0168] Among them, the normal contact force refers to the contact force between particles in the normal direction and is calculated by the processing terminal by calculating the 1.5th power of the normal overlap amount and then multiplying it by the normal stiffness coefficient.

[0169] Step S804: Analyze the tangential stiffness coefficient and the tangential relative displacement to generate the tangential contact force.

[0170] Among them, the tangential contact force refers to the contact force between particles in the tangential direction and is obtained by the processing terminal by calculating the product of the tangential stiffness coefficient and the tangential relative displacement.

[0171] Step S805: Analyze the normal damping coefficient, the normal relative velocity, the tangential damping coefficient, and the tangential relative velocity to generate the damping contact force.

[0172] Among them, the damping contact force refers to the damping force between particles and is obtained by the processing terminal by calculating the product of the normal damping coefficient and the direction relative velocity, calculating the product of the tangential damping coefficient and the tangential relative velocity, and then summing the products.

[0173] Step S806: Analyze the normal contact force, the tangential contact force, and the damping contact force to generate the total particle contact force.

[0174] Among them, the total particle contact force refers to the total contact force between particles and is obtained by the processing terminal by decomposing the normal contact force, the tangential contact force, and the damping contact force into the same coordinate system and performing vector addition.

[0175] Step S807: Analyze the total particle contact force and the preset arc length step size to generate the contact force density function.

[0176] Among them, the contact force density function in this step is the same as the contact force density function in step S700. The processing terminal calculates the resultant force of all the total particle contact forces, and then calculates the quotient of the contact force resultant force and the arc length step size, thereby mapping the contact force in the cable arc length direction according to the arc length step size, and thus defining the contact force density function.

[0177] The arc length step refers to the length of dividing the cable into several segments. In the embodiment of the present application, 0.1 m is taken as an example.

[0178] Based on the same inventive concept, the embodiment of the present application provides a minimum bending radius multi-point turning motion control system, including:

[0179] An acquisition module, configured to acquire cable parameters, cable laying ship parameters, marine environment parameters, and calculate the radius arc length;

[0180] A memory, configured to store a program of the minimum bending radius multi-point turning motion control method;

[0181] A processor, and the program in the memory can be loaded and executed by the processor and implement the minimum bending radius multi-point turning motion control method.

[0182] Those skilled in the art can clearly understand that, for the convenience and simplicity of description, only the above division of each functional module is used as an example. In practical applications, the above functions can be allocated to different functional modules according to needs, that is, the internal structure of the device is divided into different functional modules to complete all or part of the functions described above. The specific working processes of the above-described system, device, and unit can refer to the corresponding processes in the foregoing method embodiments and will not be elaborated herein.

[0183] The embodiment of the present application provides a computer-readable storage medium, storing a computer program that can be loaded and executed by a processor to implement the minimum bending radius multi-point turning motion control method.

[0184] Computer storage media include, for example: various media such as USB flash drives, mobile hard disks, read-only memories (ROM), random access memories (RAM), magnetic disks, or optical discs that can store program codes.

[0185] Based on the same inventive concept, the embodiment of the present application provides an intelligent terminal, including a memory and a processor, and a computer program that can be loaded and executed by the processor is stored on the memory to implement the minimum bending radius multi-point turning motion control method.

[0186] Those skilled in the art can clearly understand that, for the convenience and simplicity of description, only the above division of each functional module is used as an example. In practical applications, the above functions can be allocated to different functional modules according to needs, that is, the internal structure of the device is divided into different functional modules to complete all or part of the functions described above. The specific working processes of the above-described system, device, and unit can refer to the corresponding processes in the foregoing method embodiments and will not be elaborated herein.

[0187] The above are all preferred embodiments of the present application, and do not limit the protection scope of the present application accordingly. Any feature disclosed in this specification (including the abstract and drawings), unless specifically described, can be replaced by other equivalent or similar-purpose alternative features. That is, unless specifically described, each feature is only an example in a series of equivalent or similar features.

Claims

1. Method for controlling multi-point turning motion with minimum bending radius, characterized in that, Including: Obtain cable parameters of a preset cable, cable laying ship parameters of a preset cable laying ship, and ocean environment parameters; Analyze the cable parameters, cable laying ship parameters, and ocean environment parameters to generate a predicted bending radius; Analyze the cable parameters to determine the minimum bending radius; Judge whether the predicted bending radius meets the requirements of the minimum bending radius; If it meets the requirements, continue to obtain the cable parameters of the cable, the cable laying ship parameters of the cable laying ship, and the ocean environment parameters for cyclic judgment; If it does not meet the requirements, analyze the predicted bending radius and the minimum bending radius to generate a bending radius error; Analyze the bending radius error to generate a speed adjustment amount; Adjust the cable laying ship according to the speed adjustment amount so that the predicted bending radius meets the requirements of the minimum bending radius.

2. The minimum bending radius multi-point turning motion control method according to claim 1, characterized in that The steps of analyzing the cable parameters, cable laying ship parameters, and ocean environment parameters to generate a predicted bending radius include: Analyze the cable parameters to generate a static cable tension; Analyze the static cable tension, cable parameters, cable laying ship parameters, and ocean environment parameters to generate a dynamic cable tension; Analyze the dynamic cable tension and cable parameters to generate a predicted bending radius.

3. The minimum bending radius multi-point turning motion control method according to claim 2, wherein The steps of analyzing the cable parameters to generate a static cable tension include: Analyze the cable parameters to determine the unit cable weight; Analyze the unit cable weight and the minimum bending radius to generate a basic static tension; Analyze the basic static tension and a preset tension margin to generate a static cable tension.

4. The minimum bending radius multi-point turning motion control method according to claim 2, characterized in that The steps of analyzing the static cable tension, cable parameters, cable laying ship parameters, and ocean environment parameters to generate a dynamic cable tension include: Analyze the cable parameters, cable laying ship parameters, and ocean environment parameters to generate a cable tension adjustment amount; Analyze the static cable tension and the cable tension adjustment amount to generate a dynamic cable tension.

5. The minimum bending radius multi-point turning motion control method according to claim 4, characterized in that The steps of analyzing the cable parameters, cable laying ship parameters, and ocean environment parameters to generate a cable tension adjustment amount include: Analyze the cable parameters to determine the cable cross-sectional area and the real-time cable length; Analyze the cable laying ship parameters to determine the cable laying ship speed; Analyze the ocean environment parameters and the cable laying ship parameters to determine the seawater density, seawater resistance coefficient, and real-time sea current speed; Analyze the ocean environment parameters to generate a sea current speed field gradient; Analyze the seawater density, seawater resistance coefficient, cable cross-sectional area, real-time sea current speed, cable laying ship speed, sea current speed field gradient, and real-time cable length to generate a cable tension adjustment amount.

6. The method for controlling multi-point turning actions with a minimum bending radius according to claim 3, characterized in that The steps of analyzing the dynamic cable tension and cable parameters to generate a predicted bending radius include: Analyze the unit cable weight and the dynamic cable tension to generate a catenary constant; Obtain the calculated radius arc length; Analyze the dynamic cable tension, unit cable weight, calculated radius arc length, and catenary constant to generate a basic predicted radius; Analyze the catenary constant, calculated radius arc length, and cable parameters to generate a corrected bending radius; Analyze the basic predicted radius and the corrected bending radius to generate a predicted bending radius.

7. The minimum bending radius multi-point turning motion control method according to claim 6, wherein Steps for analyzing the catenary constant, calculated radius arc length, and cable parameters to generate a corrected bending radius include: Analyzing the cable parameters to generate a contact force density function; Analyzing the calculated radius arc length and the contact force density function to generate a unit contact force density; Analyzing the unit cable weight, unit contact force density, calculated radius arc length, and catenary constant to generate a corrected bending radius.

8. The minimum bending radius multi-point turning motion control method according to claim 7, characterized in that Steps for analyzing the cable parameters to generate a contact force density function include: Analyzing the cable parameters to generate a normal stiffness coefficient, tangential stiffness coefficient, normal damping coefficient, and tangential damping coefficient; Establishing a discrete particle model based on the cable parameters; Performing contact detection based on the discrete particle model to determine the contact pair particles and the corresponding normal overlap, tangential relative displacement, normal relative velocity, and tangential relative velocity; Analyzing the normal stiffness coefficient and the normal overlap to generate a normal contact force; Analyzing the tangential stiffness coefficient and the tangential relative displacement to generate a tangential contact force; Analyzing the normal damping coefficient, normal relative velocity, tangential damping coefficient, and tangential relative velocity to generate a damping contact force; Analyzing the normal contact force, tangential contact force, and damping contact force to generate a total particle contact force; Analyzing the total particle contact force and a preset arc length step to generate a contact force density function.

9. A minimum bending radius multi-point turning motion control system, characterized in that, Including: An acquisition module for acquiring cable parameters, laying vessel parameters, and ocean environment parameters; A memory for storing a program of the minimum bending radius multi-point turning motion control method according to any one of claims 1 to 8; A processor, and the program in the memory can be loaded and executed by the processor to implement the minimum bending radius multi-point turning motion control method according to any one of claims 1 to 8.

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