Self-tilting offshore floating photovoltaic platform and support method therefor

Abstract

A self-tilting offshore floating photovoltaic platform includes a membrane, photovoltaic panels, a barrier, a first mounting position and a second mounting position. The first mounting position is higher than the second mounting position, and the barrier is provided on the outer side of the second mounting position. The membrane is mounted between the first mounting position and the second mounting position, and a plurality of photovoltaic panels are mounted on the membrane; the first mounting position and / or the second mounting position are also provided with floating bodies and are connected to mooring cables. A multi-degree-of-freedom motion platform is disposed above the membrane and is provided with a multi-axis robotic arm. The self-tilting design with mounting positions at different heights achieves the capability of rapid drainage, and can reduce the impact of seawater accumulation on photovoltaic panels in cooperation with the barrier.

Description

CROSS REFERENCE TO THE RELATED APPLICATIONS

[0001] This application is based upon and claims priority to Chinese Patent Application No. 202411545989.4, filed on Nov. 1, 2024, the entire contents of which are incorporated herein by reference.TECHNICAL FIELD

[0002] The present invention belongs to the technical field of marine new energy, and particularly relates to a self-tilting offshore floating photovoltaic platform and a support method therefor.BACKGROUND

[0003] Offshore photovoltaic platforms are important facilities for developing and utilizing offshore solar energy resources. According to their supporting structure characteristics, offshore photovoltaic platforms can be divided into two categories: fixed and floating offshore photovoltaic platforms. Fixed offshore photovoltaic platforms are similar in structure to onshore photovoltaic platforms. Pile foundations are generally used in the fixed offshore photovoltaic platforms to support the upper photovoltaic modules, and this design is only suitable for shallow-water nearshore sea areas. Correspondingly, offshore floating photovoltaic platforms use floating structures to keep photovoltaic modules afloat on the water surface for power generation. This design not only saves mounting resources but also prevents water-borne structures from shading photovoltaic modules. Therefore, the offshore floating photovoltaic platforms can have better power generation efficiency and have gradually become one of the important facilities for marine new energy in the future.

[0004] On the basis of the above, floating offshore photovoltaic platforms can also be divided into two types: rigid multi-module interconnected platforms and flexible membrane platforms. Since the flexible membrane platforms are close to the sea surface, the temperature of photovoltaic modules can be reduced effectively by means of a heat exchange assembly or natural water vapor, thereby significantly improving energy conversion efficiency. However, existing floating offshore photovoltaic platforms are also prone to waves due to their close proximity to the sea surface. In addition, due to frequent precipitation at sea, this type of photovoltaic platform is prone to technical problems of easy water accumulation and difficult drainage. Furthermore, if a floating offshore photovoltaic platform needs to provide sufficient power generation, more photovoltaic panels need to be laid on the main structure. In order to meet the requirements of the floating design, the structural design strength is relatively low, and the structure is generally prone to damage. Therefore, large-scale construction equipment cannot be operated on the floating offshore photovoltaic platform, and photovoltaic modules or other components are generally handled, mounted and disassembled manually, which is labor-extensive and time-consuming and requires high mounting and post-operation and maintenance costs.

[0005] In order to solve the above problems, a lot of research has been carried out on the platform structure in the prior art. For example: Chinese invention patent application with publication number CN117326008A describes a membrane-type offshore photovoltaic power generation platform that integrates water storage and cleaning functions and prevents water accumulation. Its platform structure is mainly composed of a buoyant floating ring, a membrane-covered floating ring, stress ropes and a central floating cabin. The patent application provides an idea to solve the water accumulation and drainage problems of membrane-type offshore photovoltaic platforms, but does not specify the mounting and maintenance methods of photovoltaic panels and the corresponding equipment. And the provided cleaning method of collecting and storing rainwater and using rainwater to clean photovoltaic panels faces a practical issue that in real sea areas, rainfall will come with strong winds and large waves, and the collected water is a mixture of rainwater and seawater rather than rain water only and is not suitable for cleaning photovoltaic panels. Chinese patent publication Number CN116750144B discloses a novel membrane-type offshore photovoltaic power generation platform. Its main structure includes an air-floating pipe composed of three air-floating assemblies and a membrane for placing photovoltaic panels. The invention patent provides an idea of using a wiper blade to remove accumulated water from the platform, which is equivalent to a structure which uses a sponge wipe to clean the surfaces of photovoltaic panels and guides seawater to the sponge wipe to enhance the cleaning effect. However, inorganic salts in the seawater will remain on the surfaces of photovoltaic modules and corrode the photovoltaic modules. In addition, the sponge wipe has a limited service life and needs to be replaced regularly to ensure the cleaning effect. If the leakage of structures such as water suction pipes and solenoid valves is taken into consideration, seawater will also corrode the internal structure of the air-floating assemblies, which is detrimental to the safe operation of the photovoltaic platform.

[0006] In summary, there is also a need to design an offshore floating photovoltaic platform and a mated support method therefor, which can realize automated mounting and operation maintenance functions, and have good drainage performance to reduce the impact of seawater on photovoltaic panels or other components.SUMMARY

[0007] Aiming at the problems existing in the prior art, the present invention provides a self-tilting offshore floating photovoltaic platform and a guarantee method thereof, and solves the above problems by optimizing the overall structural design.

[0008] To achieve the above object, the technical solutions of the present invention are as follows:

[0009] In one aspect, the present invention provides a self-tilting offshore floating photovoltaic platform, which mainly includes a membrane, photovoltaic panels, a barrier, a first mounting position and a second mounting position. The first mounting position is higher than the second mounting position, and the barrier is provided on the outer side of the second mounting position.

[0010] The membrane is mounted between the first mounting position and the second mounting position, and a plurality of photovoltaic panels are mounted on the membrane.

[0011] The first mounting position and / or the second mounting position are also provided with floating bodies.

[0012] The first mounting position and / or the second mounting position are connected to mooring cables.

[0013] A multi-degree-of-freedom motion platform is disposed above the membrane and is provided with a multi-axis robotic arm.

[0014] Further, the first mounting position is designed into a cylindrical structure, and the second mounting position is designed into an annular structure.

[0015] The membrane is designed into a circular structure, with the center connected to the first mounting position and an edge connected to the second mounting position.

[0016] Further, a plurality of tension ropes are also connected between the first mounting position and the second mounting position.

[0017] The tension ropes are connected in a radial structure or a net-like structure.

[0018] Further, the floating bodies include a buoy and a buoyancy ring.

[0019] The buoy is disposed at a lower part of the first mounting position, and the second mounting position is provided with at least one buoyancy ring.

[0020] The second mounting position is also provided with an annular water collecting trough.

[0021] A drain port is provided at the lower part of the water collecting trough and is equipped with a one-way valve.

[0022] Further, the multi-degree-of-freedom motion platform includes beams, flatbed trolleys and a movable base. The beams bridge the first mounting position and the second mounting position.

[0023] One ends of the beams are connected to the movable base, and the movable base is rotatably connected to or slidingly connected to the first mounting position; the other ends of the beams are slidably connected to or lapped with the second mounting position.

[0024] The flatbed trolleys are slidably connected to the beams, and the multi-axis robotic arms are mounted on the flatbed trolleys.

[0025] Further, the movable base is higher than the second mounting position.

[0026] The movable base is provided with winch mechanisms which are connected to the flatbed trolleys by cables.

[0027] Further, stay cable structures are disposed between the movable base and the beams.

[0028] Further, a suction cup assembly or a cleaning assembly is provided at an end of the multi-axis robotic arm.

[0029] On the other hand, the present invention provides a support method based on the self-tilting offshore floating photovoltaic platform. The method includes the following steps:

[0030] according to preset instructions or system instructions, the multi-axis robotic arm is configured with working assemblies which are carried to designated positions by the multi-degree-of-freedom motion platform to carry out support operations; and

[0031] a motion trajectory of the multi-degree-of-freedom motion platform is obtained through computing by a path planning algorithm.

[0032] Further, the support operations includes photovoltaic panel mounting operation, photovoltaic panel replacement operation, and photovoltaic panel cleaning operation;

[0033] the self-tilting offshore floating photovoltaic platform is integrated with a vision recognition system which computes surface cleanliness of the photovoltaic panels; when the surface cleanliness is lower than a threshold value, the system sends a corresponding instruction for the photovoltaic panel cleaning operation;

[0034] the path planning algorithm is a savings algorithm or a genetic algorithm, and computation results of the path planning algorithm are weighted and corrected to obtain a motion trajectory of the multi-degree-of-freedom motion platform.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] The photovoltaic platform of the present invention has a simple structure and low cost. The self-tilting design with mounting positions at different heights achieves the capability of rapid drainage, and can reduce the impact of seawater accumulation on photovoltaic panels in cooperation with the barrier. In addition, by integrating the multi-degree-of-freedom motion platform additionally disposed above the membrane and the multi-axis robotic arm, the photovoltaic platform can perform complex support operations, thereby improving the overall level of automation, and reducing labor input.BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions of the embodiments of the invention, the following is a brief introduction to the drawings required in the embodiments. Obviously, the drawings described below are only some embodiments of the invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative labor.

[0038] FIG. 1 is a perspective view of a photovoltaic platform in a specific embodiment of the present invention;

[0039] FIG. 2 is a perspective view of a main body of the photovoltaic platform in a specific embodiment of the present invention;

[0040] FIG. 3 is a top view of the main body of the photovoltaic platform in a specific embodiment of the present invention;

[0041] FIG. 4 is a side view of the main body of the photovoltaic platform in a specific embodiment of the present invention;

[0042] FIG. 5 is a bottom view of the main body of the photovoltaic platform in a specific embodiment of the present invention;

[0043] FIG. 6 is a perspective view of a first mounting position in a specific embodiment of the present invention;

[0044] FIG. 7 is a partial view of a second mounting position in a specific embodiment of the present invention;

[0045] FIG. 8 is a front view of a beam in a specific embodiment of the present invention;

[0046] FIG. 9 is a top view of the beam in a specific embodiment of the present invention;

[0047] FIG. 10 is a perspective view of a multi-degree-of-freedom motion platform in a specific embodiment of the present invention;

[0048] FIG. 11 is a perspective view of a multi-axis robotic arm in a specific embodiment of the present invention;

[0049] FIG. 12 is a schematic flowchart of a savings algorithm in a specific embodiment of the present invention; and

[0050] FIG. 13 is a schematic flowchart of a genetic algorithm in a specific embodiment of the present invention.

[0051] In the figures: 1. photovoltaic panel, 2. buoyancy ring, 3. multi-functional trolley, 4. beam, 5. barrier, 6. drain port, 7. mooring cable, 8. membrane fixing ring, 9. first mounting position, 10. membrane, 11. water collecting trough, 12. multi-axis robotic arm, 13. tension rope, 14. stay cable, 15. buoy, 16. winch mechanism, 17. buoy mooring point, 18. buoyancy ring mooring point, 19. tension rope connection point, 20. buoyancy ring connector, 301. control box, 302. locking device, 401. stay cable connection buckle, 402. track, 901. cabin cover, 902. positioning bolt, 903. connecting slip ring, 1201, master arm, 1202, slave arm, 1203, first telescopic section, 1204, second telescopic section, 1205, electric joint, 1206, rotary arm, 1207, suction cup assembly.DETAILED DESCRIPTION OF THE EMBODIMENTS

[0052] In order to make the objective, technical solutions and advantages of the embodiments of the invention clearer, the technical solutions in the embodiments of the invention will be described clearly and completely in conjunction with the accompanying drawings in the embodiments of the invention. Obviously, the described embodiments are some, not all of the embodiments of the invention. Based on the embodiments of the invention, all other embodiments obtained by those of ordinary skill in the art without creative work are within the scope of the invention.

[0053] It should be noted that similar reference numerals and letters denote similar items in the accompanying drawings below; therefore, once an item is defined in a drawing, it does not need to be further defined and explained in subsequent drawings.

[0054] In the description of the invention, it should be understood that the relative relationships indicated by terms such as “outer” are based on the vertical positional relationship of the device corresponding to its mounting location in practical applications. These terms are for the convenience of describing the invention and simplifying the description, rather than indicating or implying that the referred device or component must have a specific position. Therefore, they shall not be construed as a limitation on the invention.

[0055] In the invention, unless otherwise clearly specified and limited, technical terms such as “mount” and “connect” should be understood in a broad sense. For instance, “connection” may refer to a fixed connection, a detachable connection, or an integrated connection; it may also be a direct connection or an indirect connection by means of an intermediate medium, and may further denote the internal communication between two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the invention can be understood according to specific circumstances.

[0056] It should be noted that the methods used in the invention are conventional methods, unless otherwise specified; the raw materials and devices used are conventional commercially available products, unless otherwise specified.

[0057] This embodiment provides a self-tilting offshore floating photovoltaic platform as shown in FIG. 1, which mainly includes a membrane 10, photovoltaic panels 1, a barrier 5, a first mounting position 9 and a second mounting position. The first mounting position 9 is higher than the second mounting position, and the barrier 5 is provided on the outer side of the second mounting position.

[0058] The first and second mounting positions represent the mounting structures of corresponding parts and accessories. In this embodiment, in order to maintain the stability of the main structure, the main body adopts a circular design. Referring to FIGS. 2-6, it is preferred that the first mounting position 9 is designed into a cylindrical structure and disposed at the center, and the second mounting position is designed into an annular structure and placed on the outer side. Correspondingly, the membrane 10 is designed into a circular structure, with the center connected to the first mounting position 9 and an edge connected to the second mounting position. Further, in order to enhance the stability of the main body, a corresponding connection structure needs to be designed. Therefore, in this embodiment, a plurality of tension ropes 13 are disposed between the first mounting position 9 and the second mounting position and adopt a radial design. One ends of the tension ropes 13 are connected to the first mounting position 9, and the other ends of the tension ropes 13 are connected to the second mounting position. Considering that the influence of wind and water flow during actual practice will cause torsion between the first mounting position 9 and the second mounting position, a concentric connecting slip ring 903 is disposed on a circumferential side of a central column of the first mounting position 9 and is rotatably connected to the column at the center, and a membrane fixing ring 8 is arranged on the connecting slip ring 903 to fix an edge of the membrane 10 at the center to the connecting slip ring 903 in a clamping manner, thereby completing the fixing of the membrane; the tension ropes 13 are directly connected to the connecting slip ring 903. Such a design not only ensures the cooperation between the tension ropes 13 and the membrane 10, but also allows the tension rope 13 and the membrane 10 to rotate relative to the central column. In this way, the membrane will not be damaged due to the relative rotation of the second mounting position and the first mounting position under certain working conditions, thereby facilitating the improvement of platform safety. Correspondingly, a limiting structure is also arranged between the connecting slip ring 903 and a central column buoy. Specifically, in this embodiment, the limiting structure includes a stopper and a positioning bolt 902 to complete temporary limiting, thereby limiting the torsion during support operations.

[0059] The membrane 10 functions to fix and carry the photovoltaic panels 1. In this embodiment, multiple circles of photovoltaic panels 1 arranged in an array in a circumferential direction are disposed radially on the membrane 10. This design not only transfers the weight of the photovoltaic panels 1 to the tension ropes 13 and other structures, but also prevents seawater waves from scouring the bottom of the photovoltaic panels 1. Further, the existence of the connecting slip ring 903 prevents the weight of the membrane 10 and the photovoltaic panels 1 from directly acting on the central column. The connecting slip ring 903 serves as an intermediate connection to play a buffering role, thereby improving the impact resistance and fatigue life of the central column buoy.

[0060] Further, since the first mounting position 9 and the second mounting position are flexibly connected in this embodiment, in order to make the first mounting position 9 higher than the second mounting position, a separate floating body is disposed at a lower part of the first mounting position 9, and by adjusting the buoyancy, the height of the first mounting position 9 above the sea surface is made greater than that of the second mounting position. Therefore, the floating body disposed at the lower part of the first mounting position 9 is a buoy 15. The buoy 15 adopts a small waterplane design similar to that of a semi-submersible offshore platform. The lower floating body with a large displacement volume provides the main buoyancy for the platform. Moreover, in order to reduce the wave force acting on the buoy 15, the portions of the column near and above the water surface are designed with a small diameter to reduce the waterplane area. The lower floating body part of the buoy 15 functions to provide the main buoyancy for the platform. Therefore, the lower floating body part of the buoy 15 has a large volume, specifically a considerable displacement volume, and thus a large space is provided therein. This space can be used to store batteries, emergency power supplies, power transformation equipment, platform control circuits, some spare parts, and other items.

[0061] As shown in FIGS. 1-5 and 7, a main body of the second mounting position is a floating body, which consists of a plurality of buoyancy rings 2 arranged in parallel and fixed by buoyancy ring connectors 20. An annular water collecting trough 11 is provided at the upper part of the buoyancy rings 2. The annular water collecting trough 11 not only functions for water collection, but also serves as a sidewalk during daily maintenance. The barrier 5 is disposed on a side of the water collecting trough 11 to prevent incoming waves from scouring the photovoltaic panels 1. Even if splashing seawater and rainwater fall on the photovoltaic panels 1, accumulated water will quickly gather into the water collecting trough 11 due to the inclined arrangement of the membrane. A drain port 6 is disposed at the lower part of the water collecting trough 11 and is equipped with a one-way valve, so as to quickly drain water and prevent seawater from flowing back. Further, since the buoyancy ring connectors 20 are rigid structures, tension rope connection points 19 and buoyancy ring mooring points 18 are arranged on some of the buoyancy ring connectors 20.

[0062] In order to ensure that the main body of the photovoltaic platform maintains a fixed position in the ocean, the platform is designed to be secured by a mooring system. Therefore, multiple sets of mooring cables 7 are provided, and each set is connected to the photovoltaic platform in a Y-shaped connection manner. That is, in each set, a main cable is fixed to an anchor point, while two auxiliary cables are connected to the buoy mooring point 17 and the buoyancy ring mooring point 18 respectively. This design not only ensures the stability of the platform in complex multi-field marine environments but also reduces the mooring cost.

[0063] Taking into account the need to improve the automation level of the photovoltaic platform without excessive increase in the load on the main body, in the design of this embodiment, a multi-degree-of-freedom motion platform is disposed above the membrane 10 and is provided with a multi-axis robotic arm. Further, as shown in FIGS. 1-5, 8 and 9, the multi-degree-of-freedom motion platform includes beams 4, flatbed trolleys and a movable base. The beams 4, as guiding mechanisms of the multi-degree-of-freedom motion platform, adopt a weight-reduction design with use of truss structures. And in order to maintain a balanced overall weight distribution, a symmetrical design is adopted in this embodiment, and same beams 4 are mounted on two sides of the central column, with the height near the center side being kept higher than that of outer ends. Further, considering the requirements of a working scenario, the movable base is mounted at the first mounting position 9. The movable base is configured as a turntable structure, the interior of which is driven by a rotating motor. An output shaft of the motor is engaged with an internal gear ring arranged under a tabletop via a gear set, so as to drive the movable base-beam to rotate. Preferably, a cabin cover 901 is also disposed on the tabletop of the movable base for maintenance personnel to enter and exit the movable base. One ends of the beams 4 are hinged to the movable base, and the beams 4 are then limited and fixed by a stay cable structure. To this end, a vertical support lug is also disposed in the middle of the tabletop of the movable base and is connected to stay cable connection buckles 401 correspondingly arranged on the beams 4 on the two sides by means of stay cables 14. The other ends of the beams 4 are lapped with the buoyancy rings 2 or the water collecting trough 11 by means of lockable rollers. This design allows the buoy 15 of the central column to bear the main weight of the beams 4 as well as the personnel and materials during construction. Meanwhile, this design can also reduce a bending moment on the beams 4, thereby being beneficial to improving the strength of the beams 4 and the safety of the photovoltaic platform. In this embodiment, the flatbed trolleys are configured as multi-functional trolleys 3, and the bottoms of the trolleys are in rolling contact with tracks 402 on the beams 4 by means of pulleys and are provided with clamp-type locking devices 302, as shown in FIG. 10. This design facilitates temporary fixing after the trolleys stop. A rack is provided on one side of each multi-functional trolley 3 and is configured to place the photovoltaic panels or other assemblies used for support operations. A control box 301 is mounted on the bottom of the trolley, and a trolley control system is integrated into the control box 301; the multi-axis robotic arm 12 is mounted on the other side of the trolley. In order to effectively simplify the motion mechanisms of the trolleys, in this embodiment, two winch mechanisms 16 are also provided on the movable base and are connected to the multi-functional trolleys 3 by means of cables. Due to the inclined arrangement of the beams 4 as stated above, when there is a need to move the multi-functional trolleys 3 towards the second mounting position, the cables are released by the winch mechanisms 16; and when there is a need to move the multi-functional trolleys 3 towards the first mounting position, the winch mechanisms 16 take the cables back. With this design, the weight of the trolleys can be reduced and the trolleys also can be fixed effectively, thereby avoiding the movement slippage problem of a self-propelled platform and preventing the trolleys from being blown off the photovoltaic platform by strong winds. To locate the relative positions of the multi-functional trolleys 3 on the beams 4, a positioning system is mounted between the beams 4 and each trolley to report the real-time positions of the multi-functional trolleys 3 on the beams 4.

[0064] The multi-axis robotic arms 12 serve as main work execution units. As shown in FIG. 11, this embodiment uses a robotic arm assembly different from the conventional design. The robotic arm assembly includes a master arm 1201, a slave arm 1202, an electric joint 1205, a rotary arm 1206 and a specific working assembly. A lower part of the master arm 1201 is rotatably connected to the multi-functional trolley 3, and the upper part of the master arm 1201 is connected to the slave arm 1202 by means of an electric joint. The slave arm 1202 is a three-section telescopic rod structure, including a first telescopic section 1203 and a second telescopic section 1204. An electric joint 1205 is mounted at an end of the second telescopic section 1204 to connect the second telescopic section 1204 to the rotary arm 1206. The rotary arm 1206 is connected to the specific working assembly by means of a slewing mechanism. The working assembly specifically is a suction cup assembly 1207 or a cleaning assembly (e.g., a high-pressure spray head). In this embodiment, the multi-axis robotic arm 12 can obtain a larger operation range, and when the multi-axis robotic arm 12 is stored, the center of gravity is closer to the inner side, reducing the working pressure of a mated support assembly. In addition, a camera terminal of a visual recognition system may also be mounted at an end to collect image information from more perspectives and complete information collection.

[0065] This embodiment also provides a mated support method on the basis of the self-tilting offshore floating photovoltaic platform described above. It should be noted that in the prior art, the corresponding content of the support covers mounting and maintenance. Therefore, the corresponding support operations in this embodiment include: photovoltaic panel mounting operation, photovoltaic panel replacement operation, and photovoltaic panel cleaning operation.

[0066] The specific steps are as follows:

[0067] According to preset instructions or system instructions, the multi-axis robotic arm is configured with working assemblies. The preset instructions include mounting of photovoltaic panels, dismounting of photovoltaic panels, inspection, etc. The system adopts a polar coordinate positioning method. The beams 4 rotate together with the movable base to sweep over the top of the membrane 10, and the winch mechanisms 16 control the multi-functional trolleys 3 to move to designated positions to carry out support operations.

[0068] For example, during the inspection process, a camera terminal of the multi-axis robotic arm 12 collects images of the surfaces of the photovoltaic panels 1, extracts surface features by means of an image recognition algorithm, and computes the surface cleanliness of the photovoltaic panels; when the surface cleanliness is lower than a threshold, the system sends a system instruction for cleaning the photovoltaic panels; thus, the end of the multi-axis robotic arm 12 is configured with a cleaning assembly, such as a high-pressure nozzle and a cleaning roller, to perform a corresponding operation.

[0069] Further, since the types of the above-mentioned support operations are different and all involve the motion problems of a multi-degree-of-freedom motion platform, it is required to carry out the motion trajectory planning of the multi-degree-of-freedom motion platform according to the types of the support operations, i.e., computing an optimal movement path for each operation by path planning algorithm, so as to increase work efficiency and reduce energy consumption. Therefore, the control system of each multi-functional trolley 3 has an operation path planning algorithm; when the multi-functional trolley 3 performs automated mounting of the photovoltaic panels 1, if the trolley adopts an operating method of returning to a buoyancy ring to load photovoltaic panels 1 every time a row of photovoltaic panels 1 is mounted, and then mounting the next row of photovoltaic panels 1, this will inevitably increase time costs and hinders the improvement of operating efficiency. The mounting operation path planning algorithm plans the operation path of the multi-functional trolley 3 based on the number of photovoltaic panels loaded on the multi-functional trolley and the loading positions of photovoltaic panels, and an operation path that minimizes the number of round trips the trolley makes to load photovoltaic panels is selected so that the trolley can efficiently complete the mounting operation task. The algorithm mainly realizes an optimal selection of the loading and maintenance path on the basis of the number of photovoltaic panels 1 on the multi-functional trolley 3 and the remaining mounting positions in conjunction with a savings algorithm or a genetic algorithm.

[0070] Regarding the above problems, the conditions are summarized as follows:

[0071] Objective: to plan an optimal operation path for the trolley, so that the trolley can complete the mounting of all photovoltaic panels with a limited loading capacity, while minimizing both the total travel distance and the number of round trips for loading photovoltaic panels.

[0072] Known conditions: Maximum loading capacity of a trolley: Maximum loading of photovoltaic panels at one time. Set of mounting positions of photovoltaic panels: There are Q pending mounting positions. The set of positions is denoted as P=p_1, p_2, . . . , p_N, and each position has coordinates (x_i, y_i). Storage position of photovoltaic panels (located in buoyancy rings): The storage position is denoted as D, with coordinates (x_D, y_D).

[0073] The above problem can be regarded as a Capacitated Vehicle Routing Problem (CVRP). The CVRP is a classic NP-hard problem, and the objective thereof is to plan an optimal path for a vehicle under the constraint of vehicle capacity, so as to minimize the total travel distance. Due to the exponentially increasing complexity of NP-hard problems, traditional precise algorithms cannot efficiently solve optimal solutions in large-scale problems. Therefore, heuristic algorithms (e.g., a savings algorithm) or metaheuristic algorithms (e.g., a genetic algorithm) are often used for solving such problems.

[0074] In a specific embodiment, the savings algorithm is taken as an example for illustration: As shown in FIG. 12, a mathematical model is first constructed:Decision Variables;

[0075] The formula for a path decision variable is:Xi⁢j={1,if⁢ the⁢ trolley⁢ travels⁢ from⁢ position⁢ i⁢ to⁢ position⁢ j0,otherwise;

[0076] In the formula, i, j∈{D, p_1, p_2, . . . , p_N}.

[0077] Load Variable: q_i=the number of remaining photovoltaic panels on the trolley when the trolley leaves position i.Parameter Definition;

[0078] A distance matrix is defined as:cij=(xi-xj)2+(yi-yj)2,∀i,j∈{D,p1,p2,… ,pN}

[0079] The distance Cij matrix represents an Euclidean distance between position i and position j.Objective Function;

[0080] A minimum path length is defined as:min⁢Z=∑i∑jcij·xij

[0081] In the formula, Z is a total path length.

[0082] Basic steps of trolley operation maintenance: the trolley starts from a buoyancy ring D and loads Q photovoltaic panels. Selecting an unmounted position, the trolley moves toward the unmounted position for mounting, and then the algorithm updates the load qi=q-1−1. When qi=0, the trolley returns to D for loading photovoltaic panels, then continues with the mounting operation. The above process is repeated until all photovoltaic panels are mounted.Constraints;

[0083] (1) Flow balance constraint (ensuring each mounting position is visited once) is expressed as:∑jxij=1,∀i∈P∑ixji=1,∀j∈P;

[0084] (2) Load update constraint (ensuring the number of photovoltaic panels loaded on the trolley is correct) is expressed as:Initial Condition:qD=Q;Load Update:qj=qi-dj·xij,∀i,j∈{D,P};In the formula, dj=1 indicates that one photovoltaic panel is mounted each time.

[0086] (3) Load capacity constraint (the trolley load does not exceed the maximum capacity) is expressed as:0≤qi≤Q,∀i,j∈{D,P};

[0087] (4) Return-to-load constraint (the trolley has to return to the buoyancy ring when the trolley runs out of photovoltaic panels): if qi=0, the trolley has to return to D for reloading; the return-to-load constraint is expressed as:xi⁢D=1,when⁢ qi=0;

[0088] (5) Subtour elimination constraint (preventing invalid subtours): A Miller-Tucker-Zemlin (MTZ) constraint can be adopted, expressed as:ui-uj+N·xij≤N-1,∀i≠j,i,j∈P;

[0089] In the formula, ui is an auxiliary variable representing the visiting order of node i.

[0090] Then, path computing is performed:

[0091] Initial solution construction: a separate trolley is assigned to each demand point (i.e., photovoltaic panel mounting position), with the path being from a buoyancy ring (where photovoltaic panels are stored) to the demand point and then back to the buoyancy ring. This initial scheme results in the longest total travel distance, with a path computing formula expressed as follows:Linitial=∑i=1N(ciD+cDi);

[0092] In the formula, ciD represents a distance from node i to the buoyancy ring, i.e., the photovoltaic storage position D.

[0093] Savings value computing: For any two demand points i and j(i, j∈P, i≠j)′ the formula for computing a savings value is expressed as:sij=ciD+cDj-cij;

[0094] In the formula, CiD and CDj represent distances from node i and node j to the buoyancy ring D, respectively; cij represents a distance from node i to node j. The savings value indicates a distance saved by merging the two demand points into a same path.

[0095] Sorting of savings values: All the savings values are sorted in ascending order to obtain a sorted list S.

[0096] Path merging: In the initialization, the path of each demand point is set as an independent path; after traversing the sorted savings value list S, the algorithm checks whether each sij can be merged.

[0097] Path connection: Whether two paths can be merged first requires that their end nodes (or start nodes) are adjacent. For example, end positions of path A and path B must satisfy: the last node of path A and the first node of path B can be directly connected, or the first node of path A and the last node of path B can be directly connected. This condition ensures that a merged path remains a complete continuous path rather than separate path segments.

[0098] Capacity constraint: The load capacity of a vehicle is limited. After two paths are merged, their total demand (the number of photovoltaic panels required) must not exceed the maximum load capacity Q of the vehicle. Total demand of the merged path satisfies qi+qj≤Q.

[0099] Path merging: If the conditions are met, the paths where demand points i and j are located are merged; the total demand and endpoint information of the merged path are updated.Termination Condition;

[0100] The algorithm terminates when all savings values have been processed or no more merges can be performed. The final path obtained is the optimal path derived from the savings algorithm.

[0101] In another specific embodiment, the genetic algorithm is taken as an example for illustration: As shown in FIG. 13, the algorithm gradually optimizes candidate solutions by simulating the biological evolution process to find an approximate optimal solution. The specific steps are as follows:

[0102] Encoding: The mounting sequence of photovoltaic panels and the round-trip paths of the multi-functional trolley can be represented by a permutation. Assuming there are 6 positions P1, P2, P3, P4, P5, P6 to be mounted with photovoltaic panels, a permutation (or “individual”), such as [P1, P4, P3, P6, P2, P5], can be used to represent the trolley's mounting sequence.

[0103] For each individual, the path needs to be segmented according to the trolley's load capacity Q. For example, if the trolley can only carry 2 photovoltaic panels at a time, the path represented by this individual can be divided into several segments: first mount P1, P4, then return to load and mount P3, P6, then return to load again and finally mount P2, P5.

[0104] Initial populations: Multiple randomly permuted paths are generated as initial populations, where each individual represents a different sequence of photovoltaic panel mounting by the trolley:

[0105] Fitness function: The fitness function is used to evaluate the quality of each individual (solution). The objective here is to minimize the total travel distance of the trolley. Therefore, the fitness function can be defined as the reciprocal of the total path length, with the formula expressed as:F⁡(individual)=1Total⁢ path⁢ lengh

[0106] The total path length is determined by the total travel distance required for the trolley to complete the mounting of all photovoltaic panels. For computing the path length of each individual, the trolley's load limit and the number of times the trolley returns to the buoyancy ring to load new photovoltaic panels should be taken into consideration.

[0107] Selection operation: The selection operation simulates natural selection, where individuals with higher fitness have a greater chance of being selected for the next generation. Common selection methods include roulette wheel selection or tournament selection. In roulette wheel selection, the probability of each individual being selected is proportional to its fitness.

[0108] Crossover operation: The crossover operation generates new offspring solutions from two parent solutions, and Partially Mapped Crossover (PMX) or Order Crossover (OX) is used commonly.

[0109] For example, crossover is performed using two individuals:

[0110] Parent 1: [P1, P4, P3, P6, P2, P5];

[0111] Parent 2: [P3, P1, P3, P6, P2, P4]; The offspring generated after crossover may be:

[0112] Offspring 1: [P1, P4, P5, P6, P2, P4],

[0113] Offspring 2: [P1, P4, P3, P6, P2, P3];

[0114] The offspring solutions inherit part of the path information from the parents while also forming new path combinations.

[0115] Mutation operation: The mutation operation prevents the algorithm from falling into a local optimal solution by randomly adjusting the genes of an individual. A common mutation method is swap mutation, which randomly swaps two genes in an individual.

[0116] For example, for Offspring 1 [P1, P4, P5, P6, P2, P3], we can randomly swap and obtain a new individual [P3, P4, P1, P6, P2, P3].

[0117] Iterative update: After selection, crossover, and mutation, the new generation of individuals replaces the previous generation. Through multiple iterations, individuals with higher fitness in each generation will gradually dominate, and the algorithm will eventually converge to an approximate optimal solution.

[0118] Although the approximate path solutions for the multi-functional trolley can be obtained under different embodiments, they still need to be corrected in this embodiment. The reason is that there may be a conflict between minimizing the number of round trips and minimizing the total path length. In other words, increasing the load capacity Q can reduce the number of round trips, but may lead to an excessively long path. Therefore, there is a need to find a balance between path length and the number of round trips, and the objective function can be modified as:

[0119] minZ=ΣiΣjcij·xij+λ. number of round trips;

[0120] In the formula, λ is a weight coefficient.

[0121] After further solving, computing results are obtained. Subsequently, by real-time monitoring the position of the multi-functional trolley, and based on the relative rotation angle between the buoyancy ring and the central column buoy, a displacement error compensation control algorithm is adopted to perform real-time compensation on the positions of the beams 4 and the multi-functional trolley 3 by means of controlling the operation of the driving motor of the movable base. In this way, the trolley and the photovoltaic panel mounting positions can remain relatively stationary, guaranteeing the smooth progress of mounting and operation maintenance operation.

[0122] Finally, it should be noted that the above content is only intended to illustrate the technical solutions of the invention, rather than limiting the scope of the invention. Any simple modifications or equivalent substitutions made to the technical solutions of the present invention by those skilled in the art do not depart from the essence and scope of the technical solutions of the invention.

Claims

1. A self-tilting offshore floating photovoltaic platform, comprising a membrane, photovoltaic panels, a barrier, a first mounting position and a second mounting position, wherein the first mounting position is higher than the second mounting position, and the barrier is provided on an outer side of the second mounting position;the membrane is mounted between the first mounting position and the second mounting position, and the photovoltaic panels are mounted on the membrane;the first mounting position and / or the second mounting position are provided with floating bodies;the first mounting position and / or the second mounting position are connected to mooring cables;a multi-degree-of-freedom motion platform is disposed above the membrane and is provided with a multi-axis robotic arm;the multi-degree-of-freedom motion platform comprises beams, flatbed trolleys and a movable base; the beams bridge the first mounting position and the second mounting position;one ends of the beams are connected to the movable base, and the movable base is rotatably connected to or slidingly connected to the first mounting position; the other ends of the beams are slidably connected to or lapped with the second mounting position;the flatbed trolleys are slidably connected to the beams, and the multi-axis robotic arms are mounted on the flatbed trolleys;the movable base is higher than the second mounting position;the movable base is provided with winch mechanisms which are connected to the flatbed trolleys by cables;stay cable structures are disposed between the movable base and the beams.

2. The self-tilting offshore floating photovoltaic platform according to claim 1, wherein the first mounting position is designed into a cylindrical structure, and the second mounting position is designed into an annular structure;the membrane is designed into a circular structure, with a center connected to the first mounting position and an edge connected to the second mounting position.

3. The self-tilting offshore floating photovoltaic platform according to claim 1, wherein a plurality of tension ropes are connected between the first mounting position and the second mounting position;the tension ropes are connected in a radial structure or a net-like structure.

4. The self-tilting offshore floating photovoltaic platform according to claim 2, wherein the floating bodies comprise a buoy and a buoyancy ring;the buoy is disposed at a lower part of the first mounting position, and the second mounting position is provided with at least one buoyancy ring;the second mounting position is provided with an annular water collecting trough;a drain port is provided at the lower part of the water collecting trough and is equipped with a one-way valve.

5. The self-tilting offshore floating photovoltaic platform according to claim 1, wherein a suction cup assembly or a cleaning assembly is provided at an end of the multi-axis robotic arm.

6. A support method for the self-tilting offshore floating photovoltaic platform according to claim 1, comprising the following steps:according to preset instructions or system instructions, the multi-axis robotic arm is configured with working assemblies carried to designated positions by the multi-degree-of-freedom motion platform to carry out support operations; anda motion trajectory of the multi-degree-of-freedom motion platform is obtained through computing by a path planning algorithm.

7. The support method for the self-tilting offshore floating photovoltaic platform according to claim 6, wherein the support operations comprise photovoltaic panel mounting operation, photovoltaic panel replacement operation, and photovoltaic panel cleaning operation;the self-tilting offshore floating photovoltaic platform is integrated with a vision recognition system computing surface cleanliness of the photovoltaic panels; when the surface cleanliness is lower than a threshold value, the system sends a corresponding instruction for the photovoltaic panel cleaning operation;the path planning algorithm is a savings algorithm or a genetic algorithm, and computation results of the path planning algorithm are weighted and corrected to obtain the motion trajectory of the multi-degree-of-freedom motion platform.

8. The self-tilting offshore floating photovoltaic platform according to claim 2, wherein a plurality of tension ropes are connected between the first mounting position and the second mounting position;the tension ropes are connected in a radial structure or a net-like structure.

9. The support method according to claim 6, wherein the first mounting position is designed into a cylindrical structure, and the second mounting position is designed into an annular structure;the membrane is designed into a circular structure, with a center connected to the first mounting position and an edge connected to the second mounting position.

10. The support method according to claim 6, wherein a plurality of tension ropes are connected between the first mounting position and the second mounting position;the tension ropes are connected in a radial structure or a net-like structure.

11. The support method according to claim 9, wherein the floating bodies comprise a buoy and a buoyancy ring;the buoy is disposed at a lower part of the first mounting position, and the second mounting position is provided with at least one buoyancy ring;the second mounting position is provided with an annular water collecting trough;a drain port is provided at the lower part of the water collecting trough and is equipped with a one-way valve.

12. The support method according to claim 6, wherein a suction cup assembly or a cleaning assembly is provided at an end of the multi-axis robotic arm.

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