Working capability analysis method for multi-dimensional active wave compensation crane

Abstract

The invention discloses a working capability analysis method for a multi-dimensional active wave compensation crane. The working capability analysis method comprises the following steps: S1, establishing a space rectangular coordinate system; s2, simulating six-degree-of-freedom wave frequency motion of the ship under the given sea condition, constructing a forward motion equation and a reverse solution equation of the position of the hoisted weight, and calculating a compensation instruction time sequence of each compensation mechanism on the ship under the given sea condition; s3, calculating a statistical value of the compensation instruction time sequence, establishing a judgment criterion, and judging whether the multi-dimensional active wave compensation crane can work or not; s4, determining a work capability rose diagram and a work capability look-up table diagram; and S5, calculating the annual workable probability of the multi-dimensional active wave compensation crane. According to the method, the annual workable probability of the multi-dimensional active wave compensation crane is rapidly calculated.

Description

Technical Field

[0001] The present invention relates to a heave compensation technology, and more particularly to a working capacity analysis method for a multi-dimensional active heave compensation crane. Background Art

[0002] As industries like offshore wind power installation, oil and gas development, and marine mining expand into the deep sea, offshore installation, loading and unloading, and deployment operations are subject to increasingly harsh marine environments. Offshore cranes are critical equipment for transferring cargo between the main vessel and the target offshore structure (offshore wind turbines, offshore platforms), but their operational safety and efficiency are affected by the motion of the main vessel. Main vessels are typically equipped with dynamic positioning systems (DPs) to control the low-frequency motions in the three degrees of freedom (surge, sway, and pitch) caused by second-order wave forces, thereby maintaining the basic stability of the vessel's center of gravity and bow. However, under the influence of waves, the vessel still experiences wave-frequency motions in the six degrees of freedom (surge, sway, heave, roll, pitch, and pitch) that are close to the wave period. These motions are the residual motions of the ship in dynamic positioning mode. To compensate for these motions, offshore cranes are typically equipped with multiple compensation mechanisms and a wave compensation control system, known as a multi-dimensional wave compensation crane. The heave compensation control system needs to precisely control multiple compensation mechanisms to reversely compensate for the movement of the vessel itself, thereby achieving relative stability in the position of the hoisted object and improving the efficiency and safety of the lifting operation.

[0003] During the design phase of a multi-dimensional active heave compensation crane, it's necessary to verify that the design of each compensation mechanism meets the design sea conditions. Furthermore, the crane's year-round operability in the target sea area must be analyzed. Furthermore, during actual offshore operations, it's necessary to determine whether the crane can safely operate under the current sea conditions. Therefore, operational capability analysis plays an irreplaceable role throughout the design and operational stages of a multi-dimensional active heave compensation crane.

[0004] However, there is currently no method for analyzing the working capacity of a multi-dimensional active wave compensation crane. Summary of the Invention

[0005] In response to the deficiencies in the prior art, the present invention aims to provide a method for analyzing the working capacity of a multi-dimensional active heave compensation crane. The method is capable of calculating the compensation mechanism instructions under various sea condition parameters, comparing the statistical values ​​of each compensation mechanism instruction with the design values, determining a working capacity rose diagram and a working capacity lookup table, and rapidly calculating the annual working probability of the multi-dimensional active heave compensation crane based on the hydrological statistical data and the working capacity lookup table of the target sea area.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A method for analyzing the working capacity of a multi-dimensional active heave compensation crane comprises the following steps:

[0008] S1, establish a spatial rectangular coordinate system;

[0009] S2, simulating the six-degree-of-freedom wave frequency motion of the ship under given sea conditions, constructing the forward motion equation and the inverse solution equation of the position of the suspended load, and calculating the compensation instruction time series of each compensation mechanism on the ship under the given sea conditions;

[0010] S3, calculating the statistical value of the compensation instruction time series, establishing a judgment criterion, and judging whether the multi-dimensional active wave compensation crane is operable;

[0011] S4, cyclically calculating a compensation instruction time sequence of the multi-dimensional active heave compensation crane under various sea condition parameters, judging whether the multi-dimensional active heave compensation crane is operable according to the evaluation criteria, and determining a rose diagram of the working capacity and a look-up table diagram of the working capacity;

[0012] S5, determining a method for calculating the probability that the multi-dimensional active heave compensation crane is operable throughout the year, and calculating the probability that the multi-dimensional active heave compensation crane is operable throughout the year based on the hydrological statistical data of the target sea area and the work capacity lookup table.

[0013] Preferably, in step S1, establishing the spatial rectangular coordinate system specifically includes:

[0014] Establishing an inertial coordinate system n based on the environment in which the ship is located;

[0015] Establishing a hull coordinate system b based on the appearance of the ship;

[0016] A serial coordinate system is established based on the multi-dimensional active heave compensation crane.

[0017] Preferably, in the hull coordinate system b, X b Pointing to the stern of the vessel, Y b Pointing to the starboard side of the vessel, Z b In accordance with the right-hand coordinate system rule, the origin is located at the center of gravity of the ship;

[0018] When the six degrees of freedom of motion of the ship are all zero, the inertial coordinate system n coincides with the hull coordinate system b.

[0019] Preferably, establishing a serial coordinate system based on the multi-dimensional active heave compensation crane specifically includes:

[0020] Establishing a coordinate system 0 at a base installation position of the multi-dimensional active heave compensation crane;

[0021] According to the DH law, a coordinate system i is established at the center of the i-th motion mechanism of the multi-dimensional active heave compensation crane;

[0022] If the number of motion mechanisms of the multi-dimensional active heave compensation crane is M, then the number of the serial coordinate systems is M+2;

[0023] A set Q is used to represent all compensation mechanisms on the ship.

[0024] Preferably, in step S2, simulating the six-degree-of-freedom wave frequency motion of the ship under given sea conditions specifically includes:

[0025] According to the significant wave height H S , peak period T P , determine the wave power spectrum density function S xx (ω), ω is the angular frequency;

[0026] The six-degree-of-freedom motion amplitude response operator of the ship is expressed by a transfer function:

[0027]

[0028] Among them, G l (jω, β) is the transfer function of the lth degree of freedom;

[0029] l=1,2,…,6, the first to sixth degrees of freedom are surge, sway, heave, roll, pitch and yaw respectively; A l (ω, β) is the modulus of the transfer function;

[0030] is the phase angle of the transfer function;

[0031] The power spectral density function of the six-degree-of-freedom motion response of the ship is:

[0032]

[0033] Among them, S xx (ω) is the power density of the input wave spectrum;

[0034] The time series of the six-degree-of-freedom motion response of the ship is generated according to the power spectral density function of the six-degree-of-freedom motion response of the ship using an inverse discrete Fourier transform:

[0035]

[0036] Among them, y l (n) is the motion response of the lth degree of freedom at the nth discrete time point;

[0037] N is the number of discrete time points;

[0038] dt is the time step;

[0039] is the angular frequency interval;

[0040] W[k] is the Fourier transform of a white noise time series with mean 0 and variance 1.

[0041] Preferably, in step S2, constructing the forward motion equation of the position of the hoisted object specifically includes:

[0042] Based on the series coordinate system and the DH law, a DH parameter table is established;

[0043] According to the DH rule, the DH parameter table from coordinate system i to coordinate system i-1 is determined, and the parameters include (a i-1 , α i-1 , d i ,θ i );

[0044] The coordinate transformation matrix from coordinate system M+1 to coordinate system 0 is determined according to the serial coordinate system:

[0045]

[0046] in, is the coordinate transformation matrix from coordinate system i-1 to coordinate system i;

[0047] q i is the motion stroke of the i-th motion mechanism;

[0048] When the motion range of each motion mechanism is given, the coordinate value of the compensation point in coordinate system 0 is calculated according to the following forward motion equation:

[0049]

[0050] in, is the coordinate value of the compensation point in coordinate system 0;

[0051] Coordinate transformation matrix from coordinate system 0 to the inertial coordinate system n for:

[0052]

[0053] When the six-freedom motion response of the ship and the motion range of each motion mechanism are known, the coordinate value of the compensation point in the inertial coordinate system n is determined, that is, This coordinate value can be used as the target position of the compensation point:

[0054]

[0055] Preferably, in step S2, calculating the compensation instruction time series of each compensation mechanism on the ship under given sea conditions specifically includes:

[0056] When the six-degree-of-freedom motion response of the ship is known, the expected coordinate value of the compensation point in coordinate system 0 is determined, that is,

[0057]

[0058] According to the expected coordinate value of the compensation point in coordinate system 0, combined with the forward motion equation, the motion stroke q of each compensation mechanism is solved inversely i (n):

[0059]

[0060] The corresponding motion stroke time series of each compensation mechanism is q i (n), the velocity time series and acceleration time series are:

[0061]

[0062] Preferably, in step S3, determining whether the multi-dimensional active heave compensation crane is operable specifically includes:

[0063]

[0064] Among them, h(H s ,T p ,β) is the evaluation function, when its value is 1, it means it can work, and when its value is 0, it means it cannot work;

[0065] std(·) is the standard deviation of the time series;

[0066] are the design values ​​of stroke, speed and acceleration of the i-th compensation mechanism respectively;

[0067] γ is the proportional coefficient, which is 3.7.

[0068] Preferably, in step S4, determining the work capacity rose diagram and the work capacity lookup table diagram specifically includes:

[0069] The significant wave height H S , the spectrum peak period T P and the wave direction angle β form a three-dimensional space and divide the grid evenly;

[0070] The significant wave height H at the center of the grid S , the spectrum peak period T P and the wave direction angle β as input, cyclically calculating the evaluation function value of each grid;

[0071] For a given spectrum peak period T p , determine the maximum significant wave height H at which the multi-dimensional active wave compensation crane can operate under each wave direction angle β S , the maximum significant wave height H S and the wave direction angle β are plotted in polar coordinate form into the workability rose diagram;

[0072] The significant wave height H S and the spectrum peak period T P Similarly, the evaluation function of the wave direction angle β is displayed in the significant wave height H S and the spectrum peak period T P The grid, and the significant wave height H S , the spectrum peak period T P The evaluation function of the three-dimensional space grid composed of the wave direction angle β is based on the significant wave height H S and the spectrum peak period T P The two-dimensional graphic display is drawn into the work capacity lookup table.

[0073] Preferably, in step S5, calculating the annual operability probability of the multi-dimensional active heave compensation crane specifically includes:

[0074]

[0075] Among them, P annual The probability of the multi-dimensional active heave compensation crane being operational throughout the year;

[0076] H S , peak period T P The probability that the wave direction angle β falls within the grid numbered (i1, i2, i3);

[0077] is the evaluation function of the grid center numbered (i1, i2, i3);

[0078] N Hs , N Tp , N β Significant wave height H S , peak period T P and the number of intervals of wave direction angle β.

[0079] The working capacity analysis method for a multi-dimensional active heave compensation crane provided by the present invention has the following beneficial effects:

[0080] (1) The present invention can quickly simulate the compensation mechanism instructions of a multi-dimensional active wave compensation crane under given sea conditions and determine the evaluation criteria for whether compensation is possible, allowing designers to quickly verify the feasibility of the design scheme;

[0081] (2) The present invention determines the working capacity rose diagram and working capacity lookup diagram of the multi-dimensional active heave compensation crane, so as to visualize the working capacity and determine whether the multi-dimensional active heave compensation crane is operational based on real-time sea condition parameters when in use;

[0082] (3) The present invention proposes a method for calculating the year-round operability probability of a multi-dimensional active heave compensation crane, which can quickly calculate the year-round operability probability of a multi-dimensional active heave compensation crane on a target ship and in a target sea area, and quantitatively describe its operating capability. BRIEF DESCRIPTION OF THE DRAWINGS

[0083] Figure 1 It is a schematic flow chart of the working ability analysis method of the present invention;

[0084] Figure 2 Schematic diagram of the inertial coordinate system n, the hull coordinate system b and the serial coordinate system in the working capacity analysis method of the present invention;

[0085] Figure 3 Schematic diagram of the process of step S1 in the work capability analysis method of the present invention;

[0086] Figure 4 Schematic diagram of the rose diagram of working ability in the working ability analysis method of the present invention (T P =8s);

[0087] Figure 5 It is a schematic diagram of a work capacity lookup table in an embodiment of the work capacity analysis method of the present invention. DETAILED DESCRIPTION

[0088] In order to better understand the above technical solutions of the present invention, the technical solutions of the present invention are further described below with reference to the accompanying drawings and embodiments.

[0089] Combine Figure 1 As shown, the present invention provides a method for analyzing the working capacity of a multi-dimensional active wave compensation crane, comprising the following steps:

[0090] S1, establish a spatial rectangular coordinate system;

[0091] S2, based on the spatial rectangular coordinate system established in step S1, establish an operation simulation system for the multi-dimensional active wave compensation crane, use a time-frequency conversion method to simulate the six-degree-of-freedom wave frequency motion of the ship under given sea conditions, construct a forward motion equation and an inverse solution equation for the position of the hoisted load, and calculate the compensation instruction time series of each compensation mechanism on the ship under the given sea conditions;

[0092] S3, based on the compensation instruction time series of each compensation mechanism, calculating the statistical value of the compensation instruction time series, establishing a judgment criterion, and judging whether the multi-dimensional active wave compensation crane is operable;

[0093] S4, cyclically calculating the compensation instruction time series of the multi-dimensional active wave compensation crane under various sea state parameters, judging whether the multi-dimensional active wave compensation crane is operable according to the evaluation criteria, determining a working capacity rose diagram and a working capacity lookup table diagram, and visualizing the working capacity of the multi-dimensional active wave compensation crane;

[0094] S5. Determine a calculation method for the probability that the multi-dimensional active heave compensation crane can operate throughout the year. Calculate the probability that the multi-dimensional active heave compensation crane can operate throughout the year based on the hydrological statistical data and the work capacity lookup table of the target sea area.

[0095] Combine Figure 2 and Figure 3 As shown, in the above step S1, establishing a spatial rectangular coordinate system specifically includes:

[0096] Establish an inertial coordinate system n based on the environment where the ship is located;

[0097] Establish the hull coordinate system b based on the ship's appearance;

[0098] A serial coordinate system is established based on the multi-dimensional active heave compensation crane.

[0099] In the hull coordinate system b, X b Pointing to the stern of the ship, Y b Pointing to the starboard side of the ship, Z b In accordance with the right-hand coordinate system rule, the origin is located at the center of gravity of the ship;

[0100] When the six degrees of freedom of the ship are all zero, the inertial coordinate system n coincides with the hull coordinate system b.

[0101] The establishment of a serial coordinate system based on a multi-dimensional active heave compensation crane specifically includes:

[0102] At the base installation position of the multi-dimensional active heave compensation crane, a coordinate system 0 is established. The coordinate system 0 is equivalent to translating the hull coordinate system b from the center of gravity of the ship to the base installation position.

[0103] According to the DH law, a coordinate system i is established at the center of the i-th motion mechanism of the multi-dimensional active wave compensation crane (the starting point of the rotation joint or translation joint);

[0104] If the number of kinematic mechanisms of a multi-dimensional active wave compensation crane is M, then the number of serial coordinate systems is M+2, including coordinate system 0 to coordinate system M+1. Coordinate system M+1 is generally in the same direction as coordinate system M, but the coordinate origin is located at the position where compensation is required (such as the end of the rod).

[0105] Only some of the motion mechanisms may participate in the compensation operation, and the set Q is used to represent all the compensation mechanisms on the ship.

[0106] In the above step S2, the time-frequency conversion method is used to simulate the six-degree-of-freedom wave frequency motion of the ship under a given sea condition. S , peak period T P The wave power spectrum density function is determined by using the same sea state parameters. The power spectrum density function of the ship's six-degree-of-freedom motion response is determined by combining the ship's six-degree-of-freedom motion amplitude response operator (RAO) and the wave direction angle. The inverse Fourier transform method is used to generate the time series of the ship's six-degree-of-freedom motion. Specifically, it includes:

[0107] According to the significant wave height H S , peak period T P , determine the wave power spectrum density function S xx (ω), ω is the angular frequency;

[0108] The six-degree-of-freedom motion amplitude response operator of the ship is expressed by the transfer function:

[0109]

[0110] Among them, G l (jω, β) is the transfer function of the lth degree of freedom;

[0111] l=1,2,…,6, the first to sixth degrees of freedom are surge, sway, heave, roll, pitch and yaw respectively; A l (ω, β) is the modulus of the transfer function;

[0112] is the phase angle of the transfer function;

[0113] The power spectral density function of the ship's six-degree-of-freedom motion response is:

[0114]

[0115] Among them, S xx (ω) is the power density of the input wave spectrum;

[0116] The inverse discrete Fourier transform is used to generate the time series of the ship's six-degree-of-freedom motion response according to the power spectral density function of the ship's six-degree-of-freedom motion response:

[0117]

[0118] Among them, y l (n) is the motion response of the lth degree of freedom at the nth discrete time point;

[0119] N is the number of discrete time points;

[0120] dt is the time step;

[0121] is the angular frequency interval;

[0122] W[k] is the Fourier transform of a white noise time series with mean 0 and variance 1.

[0123] In the above step S2, constructing the forward motion equation of the position of the hoisted object specifically includes:

[0124] Based on the serial coordinate system and DH law, a DH parameter table is established to determine the forward motion equation of the multi-dimensional active wave compensation crane and calculate the real-time position and target position of the compensation point;

[0125] According to the DH rule, determine the DH parameter table from coordinate system i to coordinate system i-1, the parameters include (a i-1 , α i-2 , d i ,θ i );

[0126] Determine the coordinate transformation matrix from coordinate system M+1 to coordinate system 0 based on the serial coordinate system:

[0127]

[0128] in, is the coordinate transformation matrix from coordinate system i-1 to coordinate system i;

[0129] q i is the motion stroke of the i-th motion mechanism;

[0130] When the motion range of each motion mechanism is given, the coordinate value of the compensation point in coordinate system 0 is calculated according to the following forward motion equation:

[0131]

[0132] in, is the coordinate value of the compensation point in coordinate system 0;

[0133] Coordinate transformation matrix from coordinate system 0 to hull coordinate system b Installation position IX of the crane with multi-dimensional active heave compensation b , IY b , IZ b Related, the coordinate transformation matrix from the hull coordinate system b to the inertial coordinate system n Related to the six degrees of freedom motion of the ship. Therefore, the coordinate transformation matrix from coordinate system 0 to inertial coordinate system n is for:

[0134]

[0135] When the six-freedom motion response of the ship and the motion range of each motion mechanism are known, the coordinate value of the compensation point in the inertial coordinate system n is determined, that is, This coordinate value can be used as the target position of the compensation point:

[0136]

[0137] In step S2 above, based on the forward motion equation of the multi-dimensional active heave compensation crane, an inverse solution equation is established. Based on the target position of the compensation point and the six-degree-of-freedom motion response of the ship, the travel time series of each compensation mechanism is calculated. Based on the travel time series of each compensation mechanism, the differential method is used to determine the (angular) velocity and (angular) acceleration time series of each compensation mechanism. Specifically, the following steps are involved:

[0138] The target position of the compensation point in the inertial coordinate system n can be determined according to the above steps, and its coordinate value is When the six-degree-of-freedom motion response of the ship is known, the expected coordinate value of the compensation point in coordinate system 0 is determined, that is,

[0139]

[0140] According to the expected coordinate value of the compensation point in coordinate system 0, combined with the forward motion equation, the motion stroke q of each compensation mechanism is solved inversely i (n):

[0141]

[0142] The corresponding motion stroke time series of each compensation mechanism is q i (n), the velocity time series and acceleration time series are:

[0143]

[0144] In the above step S3, based on the time series of the stroke, (angular) velocity and (angular) acceleration of each compensation mechanism, the standard deviation of each time series is calculated. The evaluation function of whether it is operable is determined to judge whether the multi-dimensional active heave compensation crane is operable. Specifically, it includes:

[0145]

[0146] Among them, h(H s , T p , β) is the evaluation function, when its value is 1, it means it can work, and when its value is 0, it means it cannot work;

[0147] std(·) is the standard deviation of the time series;

[0148] are the design values ​​of stroke, speed and acceleration of the i-th compensation mechanism respectively;

[0149] γ is the proportional coefficient, which is 3.7.

[0150] In the above step S4, determining the work capacity rose diagram and the work capacity lookup table diagram specifically includes:

[0151] There will be a significant wave height H S , peak period T P and wave direction angle β form a three-dimensional space and divide the grid evenly. The significant wave height H S The interval is 0.25m, and the spectrum peak period is T P The interval of is 1s, and the interval of wave direction angle β is 10°;

[0152] The center of the grid has a significant wave height H S , peak period T P and wave direction angle β as input, and calculate the evaluation function value of each grid cyclically;

[0153] For a given peak period T P , determine the maximum significant wave height H at which the multi-dimensional active wave compensation crane can operate under each wave direction angle β S , the maximum significant wave height H S and wave direction angle β are plotted in polar coordinate form into a workability rose diagram;

[0154] For the convenience of query, the significant wave height H S and spectrum peak period T P The evaluation function of the same wave direction angle β is concentrated on the significant wave height H S and spectrum peak period T P The grid, and the significant wave height H S , peak period T P The evaluation function of the three-dimensional space grid composed of the wave direction angle β is based on the significant wave height HS and spectrum peak period T P The two-dimensional graphic display is drawn into a work capacity lookup table.

[0155] In the above step S5, based on the hydrological statistical data of the target sea area, the probability of occurrence of each sea condition with a combination of significant wave height, spectral peak period and wave direction angle is determined, and whether each sea condition is operable is determined according to the work capability lookup table, and the annual operability probability of the multi-dimensional active heave compensation crane is calculated. Specifically, it includes:

[0156]

[0157] Among them, P annual The probability of the multi-dimensional active heave compensation crane being operational throughout the year;

[0158] H S , peak period T P The probability that the wave direction angle β falls within the grid numbered (i1, i2, i3);

[0159] is the evaluation function of the grid center numbered (i1, i2, i3);

[0160] N Hs , N Tp , N β Significant wave height H S , peak period T P and the number of intervals of wave direction angle β.

[0161] Example

[0162] Refer again Figure 2 As shown, in this embodiment, the multi-dimensional active heave compensation crane includes six motion mechanisms, of which the first, fifth, and sixth are compensation mechanisms. The crane's base was installed at a designated location on a wind turbine operation and maintenance mothership. The crane's operating capacity was analyzed, and a rose diagram and a lookup table were determined for the capacity. Finally, the wind turbine operation and maintenance mothership was placed in the target sea area for operation, and the crane's year-round operability probability was calculated.

[0163] In this embodiment, the multi-dimensional active heave compensation crane includes six motion mechanisms: the first is the main slewing mechanism, the second is the main luffing mechanism, the third is the main boom telescopic mechanism, the fourth is the upper boom luffing mechanism, the fifth is the upper boom gear sliding mechanism, and the sixth is the hook wire rope lifting mechanism. The total number of motion mechanisms is M = 6. The second, third, and fourth motion mechanisms are used for manual adjustment of the hook position to accommodate lifting operations at varying heights. The first, fifth, and sixth motion mechanisms are controlled by a heave compensation control system, which automatically adjusts their travel to ensure the three-dimensional coordinates of the load remain unchanged. The set of compensation mechanisms is Q = {1, 5, 6}. Therefore, in step S1 of the work capacity analysis method of this embodiment, the number of serial coordinate systems is 8, of which coordinate system 7 is aligned with the inertial coordinate system n in the same direction, but with its origin located at the compensation point. In this embodiment, it is necessary to establish a serial coordinate system of the 1st to 5th motion mechanisms to control the horizontal position of the compensation point, while the vertical position of the compensation point is directly controlled by the 6th motion mechanism (the wire rope is always in the vertical direction).

[0164] In this embodiment, the PM wave spectrum is selected to describe the power spectrum density of waves in the target sea area, as follows:

[0165]

[0166] In step S2 of the work capacity analysis method of this embodiment, the time step dt=0.1s, the total simulation time is 3h, the number of discrete time points N=108001, and the angular frequency interval dω=5.8E-4.

[0167] Then, the installation position of the base of the multi-dimensional active heave compensation crane is as follows:

[0168] IX b =-10.73

[0169] IY b =0

[0170] IZ b =9.60

[0171] In the work capacity analysis, the target position is generally selected as the coordinate position of the compensation point in the inertial coordinate system n when the stroke of each motion mechanism is in the middle position and the six degrees of freedom motion of the ship are all zero. Specifically:

[0172]

[0173] q1=0°, q2=45°, q3=23, q4=45°, q5=6.95, q6=0

[0174] According to the DH parameter table shown in Table 1 below, the coordinate transformation matrix between coordinate system 6 and coordinate system 0 is:

[0175]

[0176] Among them, h1 is the height of the main rotary mechanism from the base;

[0177] L2 is the distance between the luffing center of the main luffing mechanism and the slewing center of the main slewing mechanism;

[0178] L4 is the distance between the luffing center of the upper boom luffing mechanism and the end of the main boom;

[0179] h5 is the distance between the upper boom gear sliding mechanism and the luffing center of the upper boom luffing mechanism.

[0180] Table 1 DH coordinate system parameters

[0181]

[0182] In step S2 of the working capacity analysis method of this embodiment, at the discrete point n, the motion strokes of the three compensation mechanisms are:

[0183]

[0184] in, is the z-axis coordinate value of the compensation point in the inertial coordinate system n after the horizontal position of the compensation point is controlled by q1(n) and q5(n) at discrete point n;

[0185] Target value With actual value The difference is equal to the motion stroke q6(n) of the 6th compensation mechanism, thereby ensuring that the three coordinate values ​​of the hoisted object are stable at the target position.

[0186] In step S3 of the working capacity analysis method of this embodiment, the design values ​​of the three compensation mechanisms of the multi-dimensional active heave compensation crane are shown in Table 2 below:

[0187] Table 2 Compensation mechanism design parameters

[0188] Main rotary mechanism Gear sliding mechanism Wire rope lifting mechanism Stroke design value 12° 3.3m NA Speed ​​design value 10° / s 2.0m / s 2.0m / s Acceleration design value <![CDATA[10° / s 2 ]]> <![CDATA[2.0m / s 2 ]]> <![CDATA[2.0m / s 2 ]]>

[0189] In step S4 of the work capacity analysis method of this embodiment, the significant wave height H S , peak period T P The three-dimensional grid of wave direction angle β is divided into:

[0190]

[0191] Combine Figure 4 As shown, when the spectrum peak period TP When the time is 8 seconds, the capacity rose diagram shows the maximum significant wave height that the multi-dimensional wave compensation crane can withstand at different wave angles during compensation operations. The area enclosed by the blue curve represents the operable area, while the rest of the area is inoperable. Users can determine whether compensation operations are feasible based on real-time sea conditions. Thus, a capacity rose diagram is generated for each peak period, for a total of 12 diagrams.

[0192] For the convenience of query, the working capacity rose diagram under different spectral peak periods can be displayed as a two-dimensional graph of significant wave height and spectral peak period, forming a Figure 5 The work capacity lookup chart is shown. Each grid contains 12 points, representing 12 wave angles. Green indicates that the multi-dimensional wave compensation crane can operate under the sea conditions with the significant wave height and spectral peak period at the center of the grid and the corresponding wave angle. Conversely, red indicates that it cannot operate.

[0193] In step S5 of the working capacity analysis method of this embodiment, the hydrological statistical data shown in Table 3 below are used, assuming that the wave direction angle is uniformly distributed. Figure 5 According to the working capacity lookup chart, it can be calculated that the probability of the multi-dimensional wave compensation crane being able to work in the target sea area throughout the year is 95.16%.

[0194] Table 3 Hydrological statistical data of target sea area

[0195]

[0196] In summary, based on the time-frequency simulation method of a ship's six-degree-of-freedom motion and the operating principle of a multidimensional heave-compensating crane, this present invention proposes a method for analyzing the operating capacity of a multidimensional active heave-compensating crane. This method can determine the operating capacity rose diagram, operating capacity lookup diagram, and the probability that the multidimensional active heave-compensating crane can perform compensation operations year-round in a given sea area after being installed on a given ship. Specifically, based on the operating principle of the multidimensional heave-compensating crane and the DH law, this present invention establishes a serial coordinate system to determine the forward motion equations of the compensation point and the inverse equations for the motion stroke of the compensation mechanism. Furthermore, based on the inverse Fourier transform method, this present invention simulates the six-degree-of-freedom motion response of a ship under given sea conditions. Based on the inverse equations, the motion strokes of each compensation mechanism of the multidimensional active heave-compensating crane are determined. Finally, this present invention proposes a criterion for determining whether a heave-compensating crane is operational, determines the operating capacity rose diagram and lookup diagram, and establishes a method for calculating the year-round operating probability. This present invention has important guiding significance for the design of compensation mechanisms, operating capacity calculation, and online identification of operational capacity of multidimensional active heave-compensating cranes.

[0197] Those skilled in the art should recognize that the above embodiments are merely intended to illustrate the present invention and are not intended to limit the present invention. As long as they are within the spirit of the present invention, any changes or modifications to the above embodiments will fall within the scope of the claims of the present invention.

Claims

1. A method for analyzing the working capacity of a multi-dimensional active heave compensation crane, characterized by: The following steps are involved: S1, establish a spatial rectangular coordinate system; S2, simulating the six-degree-of-freedom wave frequency motion of the ship under given sea conditions, constructing the forward motion equation and the inverse solution equation of the position of the suspended load, and calculating the compensation instruction time series of each compensation mechanism on the ship under the given sea conditions; S3, calculating the statistical value of the compensation instruction time series, establishing a judgment criterion, and judging whether the multi-dimensional active wave compensation crane is operable; S4, cyclically calculating a compensation instruction time sequence of the multi-dimensional active heave compensation crane under various sea condition parameters, judging whether the multi-dimensional active heave compensation crane is operable according to the evaluation criteria, and determining a rose diagram of the working capacity and a look-up table diagram of the working capacity; S5, determining a method for calculating the probability that the multi-dimensional active heave compensation crane is operable throughout the year, and calculating the probability that the multi-dimensional active heave compensation crane is operable throughout the year based on the hydrological statistical data of the target sea area and the work capacity lookup table.

2. The working capacity analysis method for a multi-dimensional active heave compensation crane according to claim 1, characterized in that: In step S1, establishing the spatial rectangular coordinate system specifically includes: Establishing an inertial coordinate system n based on the environment in which the ship is located; Establishing a hull coordinate system b based on the appearance of the ship; A serial coordinate system is established based on the multi-dimensional active heave compensation crane.

3. The working capacity analysis method for a multi-dimensional active heave compensation crane according to claim 2, characterized in that: In the hull coordinate system b, X b Pointing to the stern of the vessel, Y b Pointing to the starboard side of the vessel, Z b In accordance with the right-hand coordinate system rule, the origin is located at the center of gravity of the ship; When the six degrees of freedom of the ship are all zero, the inertial coordinate system n coincides with the hull coordinate system.

4. The working capacity analysis method for a multi-dimensional active heave compensation crane according to claim 2, characterized in that: Establishing a serial coordinate system based on the multi-dimensional active heave compensation crane specifically includes: Establishing a coordinate system 0 at a base installation position of the multi-dimensional active heave compensation crane; According to the DH law, a coordinate system i is established at the center of the i-th motion mechanism of the multi-dimensional active heave compensation crane; If the number of motion mechanisms of the multi-dimensional active heave compensation crane is M, then the number of the serial coordinate systems is M+2; A set Q is used to represent all compensation mechanisms on the ship.

5. The working capacity analysis method for a multi-dimensional active heave compensation crane according to claim 4, characterized in that: In step S2, simulating the six-degree-of-freedom wave frequency motion of the ship under given sea conditions specifically includes: According to the significant wave height H S , peak period T P , determine the wave power spectrum density function S xx (ω), ω is the angular frequency; The six-degree-of-freedom motion amplitude response operator of the ship is expressed by a transfer function: Among them, G l (jω,β) is the transfer function of the lth degree of freedom; l=1,2,…,6, where the first to sixth degrees of freedom are surge, sway, heave, roll, pitch and yaw respectively; A l (w, β) is the modulus of the transfer function; is the phase angle of the transfer function; The power spectral density function of the six-degree-of-freedom motion response of the ship is: Among them, S xx (ω) is the power density of the input wave spectrum; The inverse discrete Fourier transform is used to generate a time series of the six-degree-of-freedom motion response of the ship according to the power spectral density function of the six-degree-of-freedom motion response of the ship: Among them, y l (n) is the motion response of the lth degree of freedom at the nth discrete time point; N is the number of discrete time points; dt is the time step; is the angular frequency interval; W[k] is the Fourier transform of a white noise time series with mean 0 and variance 1.

6. The working capacity analysis method for a multi-dimensional active heave compensation crane according to claim 5, characterized in that: In step S2, constructing the forward motion equation of the position of the suspended object specifically includes: Based on the series coordinate system and the DH law, a DH parameter table is established; According to the DH rule, the DH parameter table from coordinate system i to coordinate system i-1 is determined, and the parameters include (α i-1 , α i-1 , d i ,θ i ); The coordinate transformation matrix from coordinate system M+1 to coordinate system 0 is determined according to the serial coordinate system: in, is the coordinate transformation matrix from coordinate system i-1 to coordinate system i; q i is the motion stroke of the i-th motion mechanism; When the motion range of each motion mechanism is given, the coordinate value of the compensation point in coordinate system 0 is calculated according to the following forward motion equation: in, is the coordinate value of the compensation point in coordinate system 0; Coordinate transformation matrix from coordinate system 0 to the inertial coordinate system n for: When the six-freedom motion response of the ship and the motion range of each motion mechanism are known, the coordinate value of the compensation point in the inertial coordinate system n is determined, that is, This coordinate value can be used as the target position of the compensation point:

7. The working capacity analysis method for a multi-dimensional active heave compensation crane according to claim 6, characterized in that: In step S2, calculating the compensation instruction time series of each compensation mechanism on the ship under a given sea condition specifically includes: When the six-degree-of-freedom motion response of the ship is known, the expected coordinate value of the compensation point in coordinate system 0 is determined, that is, According to the expected coordinate value of the compensation point in coordinate system 0, combined with the forward motion equation, the motion stroke q of each compensation mechanism is solved inversely i (n): The corresponding motion stroke time series of each compensation mechanism is q i (n), the velocity time series and acceleration time series are:

8. The working capacity analysis method for a multi-dimensional active heave compensation crane according to claim 7, characterized in that: In step S3, determining whether the multi-dimensional active heave compensation crane is operable specifically includes: Among them, h(H s , T p , β) is the evaluation function, when its value is 1, it means it can work, and when its value is 0, it means it cannot work; std(·) is the standard deviation of the time series; are the design values ​​of stroke, speed and acceleration of the i-th compensation mechanism respectively; γ is the proportional coefficient, which is 3.

7.

9. The working capacity analysis method for a multi-dimensional active heave compensation crane according to claim 8, characterized in that: In step S4, determining the work capacity rose diagram and the work capacity lookup table diagram specifically includes: The significant wave height H S , the spectrum peak period T P and the wave direction angle β form a three-dimensional space and divide the grid evenly; The significant wave height H at the center of the grid S , the spectrum peak period T P and the wave direction angle β as input, cyclically calculating the evaluation function value of each grid; For a given spectrum peak period T P , determine the maximum significant wave height H at which the multi-dimensional active wave compensation crane can operate under each wave direction angle β S , the maximum significant wave height H S and the wave direction angle β are plotted in polar coordinate form into the workability rose diagram; The significant wave height H S and the spectrum peak period T P Similarly, the evaluation function of the wave direction angle β is displayed in the significant wave height H S and the spectrum peak period T P The grid, and the significant wave height H S , the spectrum peak period T P The evaluation function of the three-dimensional space grid composed of the wave direction angle β is based on the significant wave height H S and the spectrum peak period T P The two-dimensional graphic display is drawn into the work capacity lookup table.

10. The working capacity analysis method for a multi-dimensional active heave compensation crane according to claim 9, characterized in that: In step S5, calculating the annual operability probability of the multi-dimensional active heave compensation crane specifically includes: Among them, P annual The probability of the multi-dimensional active heave compensation crane being operational throughout the year; H S , peak period T P The probability that the wave direction angle β falls within the grid numbered (i1, i2, i3); is the evaluation function of the grid center numbered (i1, i2, i3); N Hs , N Tp , N β Significant wave height H S , peak period T P and the number of intervals of wave direction angle β.

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