Ship scheduling method considering tidal constraints

Abstract

The application discloses a kind of ship in and out port scheduling method considering tidal constraint, which comprises the following steps: 1) according to the real-time water depth of channel and the draft of ship, the tidal window of ship is obtained, to ensure that the bottom of ship keeps a safe gap from the bottom of channel;2) obtain the berthing time window and the departure time window of ship;3) establish scheduling optimization model;4) set constraint condition to model;5) model solution, and scheduling is carried out according to the solution result.This application considers tidal constraint and tidal current constraint simultaneously, proposes a mixed linear integer programming model, which considers the change of tidal level and the specific influence of tidal current on ship berthing and departure, and the proposed model and constraint can obtain scheduling scheme under the premise of meeting safety requirements, reduce the overall delay time of ship, and effectively improve the efficiency of port scheduling.

Description

Technical Field

[0001] This invention relates to ship scheduling technology, and more particularly to a method for scheduling ships entering and leaving ports that takes into account tidal constraints. Background Technology

[0002] Ports, as crucial nodes for cargo loading and unloading, play an irreplaceable role. Port core resources are characterized by high construction costs and long construction periods. How to develop efficient vessel scheduling plans under existing resource conditions has become a key issue in port operation and management. Currently, the main research area for improving port navigation efficiency focuses on vessel arrival and departure scheduling. Vessel arrival and departure scheduling is a comprehensive research problem involving multiple decision-making stages throughout the entire process of a vessel's arrival and departure. Among these, tides are a significant natural factor affecting vessel scheduling, especially at some open wharves, where the dynamic changes in tide levels and currents directly impact the timing of vessel arrivals and departures, as well as the safety of berthing and unberthing operations. Therefore, researching vessel scheduling strategies under tidal constraints has significant theoretical and practical value for improving port navigation efficiency and resource utilization. Existing research on vessel arrival and departure scheduling under the influence of tides mainly focuses on two aspects: berth allocation and optimization of vessel arrival and departure sequences.

[0003] In studies on berth allocation considering tidal constraints, scholars mainly focus on berth availability caused by tidal changes. Dadashi et al. considered channel depth variations and established a mathematical model for allocation and scheduling among multiple container terminals in the same port. The results showed that the model can effectively mitigate the impact of tides on the scheduling of berths at multiple shipping container terminals. Sheikholeslami et al. focused on the tidal effect, establishing a mixed-integer programming model to optimize the berth allocation problem at a port in Iran. They also conducted a sensitivity analysis of channel depth, finding that seabed dredging can significantly reduce ship delays. Wenjie et al. further considered berth depth variations, proposing a cuboid arrangement model under tidal influence, and verified its effectiveness using a two-stage greedy algorithm and a genetic algorithm.

[0004] In studies on optimizing the order of ship entry and exit under tidal constraints, the focus is on how to arrange the entry and exit sequences among ships with different drafts to reduce waiting time and channel conflicts. Existing research has yielded substantial results in modeling the impact of tide levels on ship navigation, but it still has certain limitations when considering the specific impact of tidal changes on berthing and unberthing operations. Therefore, a tidal window analysis method that combines tide level and tidal change is needed. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a method for scheduling ships entering and leaving ports that takes into account tidal constraints, in order to address the deficiencies in the prior art.

[0006] The technical solution adopted by this invention to solve its technical problem is: a method for scheduling ships entering and leaving ports considering tidal constraints, comprising the following steps: 1) Based on the real-time water depth of the channel and the ship's draft, obtain the tidal window for the ship to ensure that the bottom of the ship maintains a safe clearance from the bottom of the channel; 2) Obtain the berthing and departure time windows for vessels; 3) Establish a scheduling optimization model; 3.1) Objective Function The port vessel entry and exit scheduling model considering tidal constraints is set as follows: The objective function is to minimize the total delay time; Delay time refers to the total time loss caused by a vessel's failure to complete operations as planned during port entry and exit scheduling. It includes three aspects: berthing delay time, departure delay time, and delay time of vessels not included in the scheduling plan within the planned time.

[0007] in, The berthing delay time of a vessel refers to the difference between the actual berthing time and the estimated berthing time after the vessel arrives at the port; the departure delay time of a vessel refers to the difference between the actual departure time and the planned departure time. For the estimated berthing time of vessel i, For ships entering the port The berthing time; n1 is the number of vessels entering the port; n2 is the number of vessels departing the port; For departing vessels Departure time, The estimated departure time of the vessel, provided in advance by the terminal operator; For delays of individual vessels not included in the scheduling plan, For ships The scheduling parameters within the planned time period are set to 1 if they cannot be scheduled, otherwise they are set to 0. The planned time period refers to the continuous time range covered by the scheduling system, during which the scheduling of ships entering and leaving the port must be completed. 4) The following constraints are set for the model: 4.1) Channel constraints; including a maximum of one inbound vessel entering the channel at any given time; a maximum of one outbound vessel entering the channel at any given time; each successfully scheduled vessel may only enter the channel once; inbound vessels may not enter the channel before their arrival time; vessels may only enter the channel within their tide window. 4.2) Harbor anchorage constraints; including that each successfully dispatched vessel may only choose to use one harbor anchorage, or not use an anchorage at all; 4.3) Berthing and departure time constraints for vessels: including the berthing time for each vessel entering the port. Vessels entering the port that are included in the scheduling plan can only choose one window for berthing operations; 5) Solve the model and schedule the process based on the solution results.

[0008] According to the above scheme, the ship in step 1) Tide window The calculation is as follows: ; In the formula, Indicates the number of tide level windows. Indicates a ship The One tide level window; express The water level of the waterway at all times Indicates a ship Draft water, This refers to the safe clearance between the ship and the seabed.

[0009] According to the above scheme, in step 2), Ships Tide window The calculations are as follows, based on the berthing window and the departure window:

[0010]

[0011] In the formula, Indicates berth The direction, Indicates berth Frontier waters in The flow of time, Indicates berth Frontier waters in The flow rate of time, Indicates a ship At berth by The maximum longitudinal flow velocity for berthing and unberthing maneuvers using the berthing and unberthing method. The first ship i represents the first ship i. One berthing window, The first ship i represents the first ship i. One departure window.

[0012] According to the above scheme, the channel constraints are expressed as follows: ; ; ; ; ; in, Indicates a ship Planning time Parameters for determining entry into the waterway, if the vessel In time The value is 1 if entering the waterway, and 0 otherwise; T represents the planning time length. For ships The number of tide windows; For ships The One tide level window; According to the above scheme, the constraints of the anchorage within the port are as follows; ; ; ; ; ; ; ; ; ; Among them, a k Indicates the number of anchorages within the harbor; Indicates a ship Should the inland anchorage be used? The value is 1 if used, otherwise it is 0; Indicates a ship Planning time Parameters for determining entry into the waterway, if the vessel In time The value is 1 if the channel is entered, otherwise it is 0. The time it takes for a ship to pass through the waterway; For vessels to navigate from the channel entrance to the anchorage within the port Time; For the ship at the designated berth by The time required for berthing and unberthing maneuvers. This indicates the berthing and unberthing maneuvering mode of vessel i, with 0 for forward berthing / unberthing and 1 for turning around berthing / unberthing; For ships anchored in the port Drive to the designated parking space Time; For ships The point in time of departure from the inner anchorage; For ships The time point at which the vessel entered the inner anchorage; For departing vessels The departure time; M is a very large integer; Indicates a ship The parameter for determining whether to sail directly from the channel entrance to the designated berth without using any in-port anchorage is 1 if no in-port anchorage is used, otherwise it is 0. Indicates a ship At any moment Does it occupy the anchorage in the harbor? If occupied, the value is 1; otherwise, it is 0. According to the above scheme, the constraints on the berthing and departure times of ships are as follows; ; ; ; in, Indicates a ship Is it possible to be in the first A single berthing window can be used for berthing; if it can be set to 1, then it should be set to 0. The number of berthing windows; For ships The A berthing time window.

[0013] The beneficial effects of this invention are: The method of this invention considers both tidal level and tidal current constraints, and proposes a hybrid linear integer programming model. The model takes into account the changes in tidal level and the specific impact of tidal current on the berthing and departure of ships. The proposed model and constraints can obtain a scheduling scheme while meeting safety requirements, thereby reducing the overall delay time of ships and effectively improving port scheduling efficiency. Attached Figure Description

[0014] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings: Figure 1 This is a flowchart of a method according to an embodiment of the present invention; Figure 2 This is a schematic diagram of port layout and port entry / exit scheduling according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the berthing time window at the leading edge of a berth according to an embodiment of the present invention. Detailed Implementation

[0015] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0016] like Figure 1 As shown, a method for scheduling ships entering and leaving ports considering tidal constraints is presented. Figure 2 This is a schematic diagram of port layout and port entry / exit scheduling according to an embodiment of the present invention. The port entry / exit scheduling method includes the following steps: 1) Calculate the ship Tide window As shown in equation (1).

[0017] (1) In the formula, Indicates the number of tide level windows. Indicates a ship The One tide level window. express The water level of the waterway at all times Indicates a ship Draft water, This refers to the safe clearance between the vessel and the seabed. The range of the tide window is determined by the real-time water depth of the channel, ensuring that the safe clearance between the bottom of the vessel and the bottom of the channel is not less than [amount missing]. This can reduce the risk of grounding, which is especially important for deep-draft vessels.

[0018] 2) Trend window; The tidal current window primarily affects berthing and unberthing operations and must be completed under suitable current speed and direction. Specifically, when a vessel approaches the waters in front of the berth, to maintain sufficient rudder effectiveness, it must maneuver during periods of strong current to ensure stability. However, for safety reasons, berthing and unberthing operations should also be performed during periods of gentle current. The tidal current window includes both the berthing and unberthing time windows. Tide window The calculations are shown in equations (2) to (3).

[0019] (2) (3) In the formula, Indicates berth The direction, Indicates berth Frontier waters in The flow of time, Indicates berth Frontier waters in The flow rate of time, Indicates a ship At berth by The maximum longitudinal flow velocity at which berthing and unberthing operations can be performed. , They represent the first There are berthing and unberthing windows. The range of the tidal window is determined by the current speed and direction in the waters in front of the berth, ensuring that the vessel can maneuver against the current during berthing and unberthing maneuvers, and guaranteeing that maneuvers can be performed within the current. This can be completed within a certain range. This not only avoids the risk of the ship deviating from its course due to excessive current speed, but also improves the rudder stability of the ship during berthing and unberthing, which is especially crucial for large ships with deep draft and low maneuverability.

[0020] Figure 3 This displays the berthing time window for the waters in front of a certain berth. To better illustrate the ebb and flow trends, all tide data are based on an average level of 0.1m. (Wharf orientation) As shown in the figure, the lateral component of the tidal current relative to the quay is generally small, thus having a relatively minor impact on berthing and unberthing maneuvers. The longitudinal component varies periodically with flow direction and velocity. Taking berthing as an example, when the longitudinal velocity is less than... Furthermore, vessels can berth when the longitudinal current velocity is greater than 0. This time period is considered the vessel's berthing period. berth The berthing window (yellow area). In open quays, the time window for berthing maneuvering is usually short. When the actual berthing time exceeds this time window, the current situation becomes complicated, and the vessel needs to move to the anchorage to wait for the next berthing window.

[0021] 3) Establish an optimization model for ship arrival and departure scheduling; 3.1) Basic Assumptions of the Model For ease of modeling, the following assumptions are made: 3.1. 1) All time-related units in the model are safety intervals. Multiples of [a certain value]. By setting safety clearance parameters, ships can maintain a certain time interval during operations in the same channel or berth to avoid the risk of collisions due to insufficient maneuvering time. At the same time, all time-related units are set to [a certain value]. Multiples of this can unify the time scale in the scheduling cycle, thereby simplifying the calculation process.

[0022] 3.1.2) The berth layout is a discrete layout.

[0023] 3.1.3) The layout of the anchorages in the port is discrete, and each anchorage can only accommodate a maximum of one vessel.

[0024] 3.1.4) All ships in the channel have constant and identical speeds and the same travel time between any two points in the port waters.

[0025] 3.1.5) The arrival time, sailing time and departure time of the vessel are all known.

[0026] For ease of description, the inbound vessels will be numbered 1 to 1. Departing vessel number arrive Problem P can be modeled as a mixed linear integer programming (MILP) problem.

[0027] 3.2) Decision variables and input parameters The decision variables are as follows: Ships In time Entering the channel equals 1, otherwise it equals 0; Ships Use of anchorage within the harbor It is 1 if it is true, otherwise it is 0. Ships 1 indicates sailing directly from the channel entrance to the designated berth without using any in-port anchorage; otherwise, 0 indicates sailing. Ships At any moment Occupy anchorage in the harbor It is 1 if it is true, otherwise it is 0. Ships In the first A berthing window is 1 if it is berthed, otherwise it is 0; Ships The time point at which the vessel entered the inner anchorage; Ships The point in time of departure from the inner anchorage; Vessels entering the port berthing time; Departing vessels Departure time; Ships If a function cannot be scheduled within the planned time, it is set to 1; otherwise, it is set to 0.

[0028] 3.3) Objective Function 3.3.1) Objective Function The port vessel entry and exit scheduling model considering tidal constraints is set as follows: The objective function is shown in equation (4), which aims to minimize the total delay time. Delay time refers to the total time loss incurred by ships during port entry and exit scheduling due to various factors that prevent them from completing operations as planned. It includes three aspects: berthing delay time, departure delay time, and delay time of ships not included in the scheduling plan within the planned time.

[0029] (4) Berthing delay time: The terminal will determine the estimated berthing time for arriving vessels in advance. The berthing delay time of a vessel refers to the difference between the actual berthing time after the vessel arrives at the port and the estimated berthing time. It is the time difference that occurs when a vessel entering the port fails to berth as planned due to tidal windows, berth arrangements, or other reasons.

[0030] Departure delay time: Departure vessels Must be within the specified time Departure from anchorage. This refers to the estimated departure time of a vessel, which is usually given in advance by the terminal. The vessel's departure delay time is the difference between the actual departure time and the planned departure time.

[0031] Delay time of vessels not included in the scheduling plan: During the scheduling process, if a vessel is unable to berth or depart within the planned time, the terminal operator needs to reassess and revise the vessel's berth plan. In this case, the vessel will be included in the scheduling plan for the next planning cycle to ensure that subsequent scheduling tasks are not affected by its delay. To quantify this process, variables are introduced. Record relevant data. However, revising the scheduling plan for a single vessel may have a ripple effect on the scheduling arrangements of all vessels in the next planning cycle, potentially even requiring a readjustment of the entire cycle's scheduling plan. Therefore, by introducing a parameter... This indicates the delay time of a single ship that was not included in the scheduling plan within the planning period.

[0032] 4) Model constraints 4.1) Equations (5)-(9) are the channel constraints. Equation (5) indicates that at most one inbound vessel can enter the channel at any given time. Equation (6) indicates that at most one outbound vessel can enter the channel at any given time. Equation (7) indicates that each successfully scheduled vessel can only enter the channel once. Equation (8) stipulates that inbound vessels cannot enter the channel before their arrival time. Equation (9) indicates that vessels can only enter the channel within their tide window.

[0033] (5) (6) (7) (8) (9) 4.2) Equations (10)-(18) are constraints on anchorages within the port. Equation (10) indicates that each successfully scheduled vessel can only choose to use one anchorage within the port, or not use any anchorage. Equations (11) and (12) specify the time for inbound vessels to use anchorages within the port. Equations (13) and (14) specify the time for outbound vessels to use anchorages within the port. Equation (15) is related to the variable. , and This indicates that if a vessel uses an anchorage within the port, ;otherwise, When ships use anchorages within the port, by means of restraint and The value specifies the time for a vessel to enter and leave the anchorage within the port. Equation (16) is the capacity constraint for the anchorage within the port, ensuring that at most one vessel can use each anchorage within the port at any given time. Equations (17)-(18) specify the usage time of the anchorage within the port. Equation (17) ensures that vessels... exist hour, Set to 1, thus defining the ship. Should anchorage be used? The time frame ensures the rational allocation of anchorage resources. Equation (18) represents the ship's... Use of anchorage within the harbor Then it must be Use At any time, ensure variables The recorded anchorage usage time and , The time range is consistent, thus reflecting the actual time the ship spends at anchorage.

[0034] (10) (11) (12) (13) (14) (15) (16) (17) (18) 4.3) Equations (19)-(21) represent the berthing time and departure time of the vessel, respectively. Equation (19) specifies the berthing time for each vessel entering the port. The vessel must be within the designated berthing window. Equation (20) stipulates that an inbound vessel included in the scheduling plan can only choose one window for berthing. Equation (21) represents the departure time of a departing vessel, indicating that the vessel is allowed to depart earlier than the scheduled departure time. It also stipulates... , indicating ships Unable to be scheduled.

[0035] (19) (20) (twenty one) Equations (22)-(29) specify the binary nature and non-negativity of variables.

[0036] (twenty two) (twenty three) (twenty four) (25) (26) (27) (28) (29).

[0037] 5) Solve the model and perform scheduling based on the scheduling scheme derived from the solution; The Lagrange relaxation algorithm preserves most of the structure of the original problem, making it easier to generate a higher-quality feasible solution to the original problem by solving the relaxation problem. In the original problem... In this context, constraint (16) has strong coupling. By relaxing constraint (16) and multiplying by Lagrange multipliers, And placed in the problem From the objective function, we obtain the following relaxation problem: 5.1) Mathematical Model of Relaxation Problem (30) Constraints: (5)-(15), (17)-(29). In equation (30), express A matrix of values, Indicating relaxation issues To find the optimal objective function value, the dual problem is constructed as follows:

[0038] The goal of the Lagrange relaxation heuristic algorithm is to solve the dual problem. By solving the relaxation problem Find the original problem The lower bound of the optimal solution Then, find a maximum value from all the obtained lower bounds, generating a good lower bound during the process of finding a good lower bound. The optimal feasible solution.

[0039] 5.2) Solving the Lagrange relaxation problem To solve the relaxation problem, observe Remove the constant term from the objective function. It can be decomposed into two independent subproblems: (1) Subproblem 1: Mathematical model of ships entering the port (31) Constraints: (5), (7)-(12), (15), (17)-(20), (22)-(28).

[0040] (2) Subproblem 2: Mathematical model of departing vessels (32) Constraints: (6)-(7), (9)-(10), (13)-(15), (17)-(18), (21)-(26), (29). (3) Solving subproblems To facilitate the solution and This is transformed into a non-standard assignment problem by constructing a cost matrix. First, for... , time Expand to Used to represent the variables of ships entering the port. Define its cost matrix. , , indicating in the subproblem Inbound vessels exist The cost of entering the waterway at any time.

[0041]

[0042] in Indicates ships entering the port exist Always enter the channel and use the port anchorage Cost, definition for:

[0043] Obtain the cost matrix After that, subproblems This can be transformed into a problem. Assuming for The optimal objective function value is also The optimal objective function value.

[0044]

[0045] Constraints:

[0046]

[0047]

[0048] right Perform the same processing, and change the time. Expand to Define the cost matrix for departing vessels. .

[0049]

[0050] Indicates departing vessels exist Always enter the channel and use the port anchorage The cost.

[0051]

[0052] Similarly, subproblems Transform into Assuming for The optimal objective function is:

[0053] Constraints:

[0054]

[0055]

[0056] and Non-standard assignment problems of two scales can be solved using the Hungarian algorithm after the cost matrix is ​​completed into a square matrix. Therefore, for relaxation problems... The optimal solution is:

[0057] 5.3) Subgradient Optimization Algorithm and Upper Bound Calculation Strategy Since the lower bound solution obtained in the relaxation problem does not necessarily satisfy equation (16), Indicates the first The multiplier at the next iteration, according to Rizk, has been proven to be relevant to the solution of the relaxation problem in the subgradient optimization algorithm. Adding perturbations may generate better feasible solutions. Therefore, Obtained from the middle As input, a binary decision variable is introduced, and the problem is... Transformed into a resource-constrained project scheduling problem By solving Repairable The infeasible solution obtained from this. Define a set. , It includes all ships included in the scheduling plan. Define decision variables. (ships) Compared to ships Early arrival at the inner anchorage If it is 1, then it is 1; otherwise, it is 0. Then there is the resource-constrained project scheduling problem. for: (33) Constraints: (10)-(15), (19)-(21), (23), (25)-(29).

[0058] (34) (35) (36) Although in the problem While the entry time into the channel is known, the complexity of scheduling lies in effectively allocating anchorage resources to ensure that all vessels berth within the berthing window, thereby guaranteeing all vessels operate as planned and minimizing total delays. middle, Transform into input parameters, introduce Removed time Dimension. Equations (34) and (35) ensure that the time used by vessels anchored in the same port does not overlap by determining their order.

[0059] The multipliers are updated using a standard subgradient optimization algorithm, and the update method for the multipliers is as follows: (37) In equation (37), express A matrix of values, where .exist Building on the solution , Indicates the first The step size in the next iteration is: (38) Indicates in The optimal solution is obtained from the process. When the optimality gap... or number of iterations The algorithm terminates when the time is right.

[0060] It should be understood that those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A method for scheduling ship entry and exit from ports considering tidal constraints, characterized in that, Includes the following steps: 1) Based on the real-time water depth of the channel and the ship's draft, obtain the tidal window for the ship to ensure that the bottom of the ship maintains a safe clearance from the bottom of the channel; 2) Obtain the berthing and departure time windows for vessels; 3) Establish a scheduling optimization model; 3.1) Objective Function The port vessel entry and exit scheduling model considering tidal constraints is set as follows: The objective function is to minimize the total delay time; Delay time refers to the total time loss caused by a vessel's failure to complete operations as planned during port entry and exit scheduling. It includes three aspects: berthing delay time, departure delay time, and delay time of vessels not included in the scheduling plan within the planned time. in, The berthing delay time of a vessel refers to the difference between the actual berthing time and the estimated berthing time after the vessel arrives at the port; the departure delay time of a vessel refers to the difference between the actual departure time and the planned departure time. For the estimated berthing time of vessel i, For ships entering the port The berthing time; n1 is the number of vessels entering the port; n2 is the number of vessels departing the port; For departing vessels Departure time, The estimated departure time of the vessel, provided in advance by the terminal operator; For delays of individual vessels not included in the scheduling plan, For ships The scheduling parameter within the planned time period is set to 1 if it cannot be scheduled, and 0 otherwise. 4) The following constraints are set for the model: 4.1) Channel constraints; including a maximum of one inbound vessel entering the channel at any given time; a maximum of one outbound vessel entering the channel at any given time; each successfully scheduled vessel may only enter the channel once; inbound vessels may not enter the channel before their arrival time; vessels may only enter the channel within their tide window. 4.2) Harbor anchorage constraints; including that each successfully dispatched vessel may only choose to use one harbor anchorage, or not use an anchorage at all; 4.3) Berthing and departure time constraints for vessels: including the berthing time for each vessel entering the port. Vessels entering the port that are included in the scheduling plan can only choose one window for berthing operations; 5) Solve the model and schedule the process based on the solution results.

2. The method for scheduling ships entering and leaving ports considering tidal constraints according to claim 1, characterized in that, The ship in step 1) Tide window The calculation is as follows: ； In the formula, Indicates a ship The One tide level window; express The water level of the waterway at all times Indicates a ship Draft water, To ensure a safe clearance between the ship and the seabed, u 1i Indicates a ship The number of tide level windows.

3. The method for scheduling ships entering and leaving ports considering tidal constraints according to claim 1, characterized in that, In step 2), Ships Tide window The calculation is as follows: In the formula, Indicates berth The direction, Indicates berth Frontier waters in The flow of time, Indicates berth Frontier waters in The flow rate of time, Indicates a ship At berth by The maximum longitudinal flow velocity for berthing and unberthing maneuvers using the berthing and unberthing method. The first ship i represents the first ship i. One berthing window, The first ship i represents the first ship i. One departure window; u 2i Indicates a ship The number of berthing and departure windows.

4. The method for scheduling ships entering and leaving ports considering tidal constraints according to claim 1, characterized in that, In step 4), the channel constraints are expressed as follows: ； ； ； ； ； in, Indicates a ship Planning time Parameters for determining entry into the waterway, if the vessel In time The value is 1 if entering the waterway, and 0 otherwise; T represents the planning time length. For ships The number of tide windows; For ships The One tide level window.

5. The method for scheduling ships entering and leaving ports considering tidal constraints according to claim 1, characterized in that, In step 4), the anchorage constraints within the port are as follows; ； ； ； ； ； ； ； ； ； Among them, a k Indicates the number of anchorages within the harbor; Indicates a ship Should the inland anchorage be used? The value is 1 if used, otherwise it is 0; Indicates a ship Planning time Parameters for determining entry into the waterway, if the vessel In time The value is 1 if the channel is entered, otherwise it is 0. The time it takes for a ship to pass through the waterway; For vessels to navigate from the channel entrance to the anchorage within the port Time; For the ship at the designated berth by The time required for berthing and unberthing maneuvers. This indicates the berthing and unberthing maneuvering mode of vessel i, with 0 for forward berthing / unberthing and 1 for turning around berthing / unberthing; For ships anchored in the port Drive to the designated parking space Time; For ships The point in time of departure from the inner anchorage; For ships The time point at which the vessel entered the inner anchorage; For departing vessels The departure time; M is a very large integer; Indicates a ship The parameter for determining whether to sail directly from the channel entrance to the designated berth without using any in-port anchorage is 1 if no in-port anchorage is used, otherwise it is 0. Indicates a ship At any moment Does it occupy the anchorage in the harbor? If occupied, the value is 1; otherwise, it is 0.

6. The method for scheduling ships entering and leaving ports considering tidal constraints according to claim 1, characterized in that, In step 4), the constraints on the berthing and departure times of the vessel are as follows; ； ； ； in, Indicates a ship Is it possible to be in the first A single berthing window can be used for berthing; if it can be set to 1, then it should be set to 0. The number of berthing windows; For ships The A berthing time window; u 2i Indicates a ship The number of berthing and departure windows.

7. An electronic device, characterized in that, include: One or more processors; as well as Storage device for storing one or more programs. Wherein, when the one or more programs are executed by the one or more processors, the one or more processors perform the method according to any one of claims 1 to 6.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the method described in any one of claims 1 to 6.

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