Inspection plan optimization method, system and device

Abstract

The present invention provides an inspection plan optimization method, comprising: determining a target expression based on the decision variables of the original plan and the adjusted decision variables; determining a target function based on the target expression, wherein the target function is a plan change minimum target function; and determining an inspection plan according to the plan change minimum target function. The present invention can scientifically reduce the negative impact of plan changes on the overall plan execution and generate an optimized inspection plan.

Description

Technical Field

[0001] The present invention belongs to the field of rail transit, and in particular relates to an inspection plan optimization method, system and device. Background Art

[0002] With the development of high-density and high-speed rail transit, the safe and uninterrupted operation of trains and the comfortable travel of passengers have put forward higher requirements for the reliability and stability of rail transit infrastructure. In order to ensure that managers can timely perceive the quality status of rail transit linear assets, effectively arrange maintenance and repair operations, and maintain railway facilities in accordance with relevant regulations, rail transit linear assets should be inspected in a planned and periodic manner using various inspection methods. In the actual implementation process, due to the interference of various random factors, the rail transit linear asset inspection plan may be adjusted many times. How to minimize the changes in the inspection plan to ensure the guidance of the rail transit linear asset inspection plan is an important problem faced by managers.

[0003] In rail transit production practice, rail transit linear asset inspection plans are generally manually compiled and adjusted by managers based on experience, which makes it difficult to ensure the optimization of inspection plans and minimize plan changes. Traditional network planning methods or Gantt chart methods are not applicable to linear asset inspection activities. At present, there are few direct studies on the optimization and adjustment of transportation infrastructure inspection plans. Research on inspection plans focuses on the optimal selection of transportation infrastructure inspection methods based on safety, cost and other goals, or focuses on the optimization of the number of inspections of the same inspection method and the time interval between two adjacent inspections within a certain planning cycle. These studies have ignored the need for adjustment of inspection plans during execution. If the inspection plan is recompiled directly based on the remaining inspection workload, it is easy to disrupt the original inspection plan's arrangement of labor, materials, machinery and other resources. Existing research results on the preparation of transportation infrastructure inspection plans cannot be directly applied to the adjustment of inspection plans.

[0004] When the inspection plan is actually executed, due to the interference of various random factors, the actual progress of the inspection plan will deviate from the plan. Therefore, in order to ensure the guidance of the inspection plan, how to reasonably adjust the inspection plan and reduce the impact of the changes on the maintenance work has become a technical problem that needs to be solved in the field of rail transit. Summary of the invention

[0005] In view of the above problems, the present invention provides an inspection plan optimization method, comprising:

[0006] Determine the target expression based on the original planned decision variables and the adjusted decision variables;

[0007] Determining an objective function based on the objective expression, wherein the objective function is a plan change minimum objective function;

[0008] The inspection plan is determined based on the objective function of minimizing plan changes.

[0009] Furthermore, determining the objective function includes:

[0010] Determine decision variables based on the rail transit space-time grid, and determine the objective function based on the rail transit space-time grid and the decision variables;

[0011] The decision variables are used to represent the execution status of the specified inspection activities in the space-time grid.

[0012] Further,

[0013] The objective function is to minimize the sum of the absolute values ​​of the decision variable differences of the rail transit space-time grid from the start unit time of the inspection plan adjustment to the end time of the inspection plan;

[0014] The method for determining the sum of the absolute values ​​of the decision variable differences is: for each inspection method of each rail transit space-time grid, determine the difference between the decision variable after the plan adjustment and the original plan value; and sum the multiple differences obtained.

[0015] Further,

[0016] The objective function is to minimize the value of the objective expression A.

[0017]

[0018] in, is the decision variable of the original plan, The adjusted decision variable, h, indicates that the inspection plan needs to be re-compiled starting from the hth unit of time;

[0019] Among them, the decision variables It indicates whether the i-th rail transit linear asset grid performs the inspection activity of the j-th inspection method in the e-th unit time. N represents the total number of grids divided by the rail transit linear asset line. M represents the total number of categories of rail transit linear asset inspection methods. E represents the total number of unit times in a planning cycle. e represents the e-th unit time.

[0020] The present invention also provides an inspection plan optimization system, comprising:

[0021] A target determination unit, used for determining a target expression based on the original planned decision variables and the adjusted decision variables;

[0022] An objective function determination unit, configured to determine an objective function based on the objective expression, wherein the objective function is a plan change minimum objective function;

[0023] The inspection plan determination unit determines the inspection plan based on the objective function of minimizing plan changes.

[0024] Further, the objective function determining unit determines the objective function including:

[0025] Determine decision variables based on the rail transit space-time grid, and determine the objective function based on the rail transit space-time grid and the decision variables;

[0026] The decision variables are used to represent the execution status of the specified inspection activities in the space-time grid.

[0027] Further,

[0028] The objective function is to minimize the sum of the absolute values ​​of the decision variable differences of the rail transit space-time grid from the start unit time of the inspection plan adjustment to the end time of the inspection plan;

[0029] The method for determining the sum of the absolute values ​​of the decision variable differences is: for each inspection method of each rail transit space-time grid, determine the difference between the decision variable after the plan adjustment and the original plan value; and sum the multiple differences obtained.

[0030] Furthermore, the objective function is to minimize the value of the objective expression A.

[0031]

[0032] in, is the decision variable of the original plan, The adjusted decision variable, h, indicates that the inspection plan needs to be re-compiled starting from the hth unit of time;

[0033] Among them, the decision variables It indicates whether the i-th rail transit linear asset grid performs the inspection activity of the j-th inspection method in the e-th unit time. N represents the total number of grids divided by the rail transit linear asset line. M represents the total number of categories of rail transit linear asset inspection methods. E represents the total number of unit times in a planning cycle. e represents the e-th unit time.

[0034] The present invention also provides an inspection plan optimization device, the device comprising at least one processor and at least one memory;

[0035] The memory stores a computer program for executing the above method, and the processor calls the computer program in the memory to execute the above method.

[0036] The inspection plan optimization method, system and device of the present invention are of great significance for ensuring the guidance of the inspection plan during its execution, reducing the various negative impacts on other related work arrangements when the inspection plan is adjusted, and ensuring the smooth completion of the scheduled rail transit linear asset inspection work. The technical solution of the present invention subdivides the rail transit linear asset inspection activities in time and space dimensions according to units of equal length, and defines in more detail the various time and space constraints and objective functions of different inspection activities of rail transit linear assets. The objective function takes into account the minimum change of the rail transit linear asset inspection plan compared with the original plan, thereby scientifically reducing the negative impact of plan changes on the overall plan execution, and ensuring the smooth completion of maintenance activities, and can use the model to generate an optimized inspection plan.

[0037] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0039] Figure 1 A schematic diagram showing adjacent inspection time intervals of inspection activities in different inspection modes according to an embodiment of the present invention is shown;

[0040] Figure 2 A schematic diagram of a flow chart of an inspection plan optimization method according to an embodiment of the present invention is shown;

[0041] Figure 3 A schematic diagram of a railway space-time grid according to an embodiment of the present invention is shown;

[0042] FIG4( a ) shows a schematic diagram of a rail transit linear asset inspection activity based on a time-space grid according to an embodiment of the present invention;

[0043] FIG4( b ) shows a schematic diagram of space-time constraints of two adjacent activities of a rail transit linear asset based on a space-time grid according to an embodiment of the present invention;

[0044] Figure 5 The decision variables in the model OAMIS-TG according to an embodiment of the present invention are shown. Schematic diagram;

[0045] Figure 6 A schematic diagram of time constraints based on a rail transit space-time grid according to an embodiment of the present invention is shown;

[0046] Figure 7 A schematic diagram of construction period constraints based on rail transit time-space grid according to an embodiment of the present invention is shown;

[0047] Figure 8 A schematic diagram of spatial constraints based on a rail transit space-time grid according to an embodiment of the present invention is shown;

[0048] Fig. 9 A schematic diagram of rate constraints based on a rail transit space-time grid according to an embodiment of the present invention is shown;

[0049] Fig.10 A schematic diagram of resource constraints based on a rail transit space-time grid according to an embodiment of the present invention is shown;

[0050] Fig.11 A schematic diagram of continuity constraint based on rail transit space-time grid according to an embodiment of the present invention is shown;

[0051] Fig.12 The figure shows the down track inspection plan diagram of the Lanzhou-Xinjiang Line compiled by the Jiayuguan Line Workshop of the Lanzhou Railway Bureau in December 2016 according to the model OAMIS-TG of an embodiment of the present invention;

[0052] Fig.13 A comparison diagram before and after the adjustment of the down track inspection plan of the Lanzhou-Xinjiang Line of the Jiayuguan Line Workshop of the Lanzhou Railway Bureau in December 2016 is shown according to an embodiment of the present invention;

[0053] Fig.14 A schematic diagram of the structure of an inspection plan optimization system according to an embodiment of the present invention is shown;

[0054] Fig.15 A schematic structural diagram of another inspection plan optimization device according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0055] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0056] Linear assets refer to assets that have a measured starting point and end point and can be maintained in sections. IBM defines linear assets as assets that are maintained in sections, and measurements can be taken along the linear assets to specify work, monitoring, metering, marking locations, etc. For linear assets, their length plays a key role in maintenance. For example, the tracks, roadbeds, contact lines, tunnels, bridges and other equipment in rail transit infrastructure are all linear assets, which have the characteristics of linear, continuous, and strip layout in spatial distribution. Their inspection activities are organized in relatively small, strip-shaped spaces and are easily affected by various time and space factors.

[0057] During the implementation of the rail transit linear asset inspection plan, it is inevitable that it will be affected by various random disturbances (such as bad weather conditions), making the actual inspection progress inconsistent with the plan. At this time, it is necessary to adjust the unimplemented part of the inspection plan to minimize the change compared with the original plan while completing the remaining inspection tasks, so as to avoid delays in inspection activities or disrupt the inspection plan's arrangement of maintenance resources such as labor, materials, and machinery. Figure 1 As shown, the check activity j can be at its minimum rate minv j With the maximum rate maxv j Adjust within the constraints and check the area ΔS between the original plan of activity j and the changed plan j′ j The smaller it is, the smaller the change in the adjusted plan is compared with the original plan. In the figure, the horizontal axis represents mileage, the vertical axis represents time, the dotted line j and the double-line broken line j′ represent the inspection activities before and after the adjustment, the oblique line shaded area represents the variable range of the activity rate, the horizontal dotted line represents the current date, the part below the horizontal dotted line is the inspection plan that has been executed, and the part above the horizontal dotted line is the inspection plan that has not been executed.

[0058] There are many types of rail transit linear asset inspection methods, and the inspection principles of different inspection methods are different, but in general, rail transit linear asset inspection activities have the following characteristics:

[0059] (1) Rail transit linear asset inspection activities are continuous in the horizontal direction; rail transit linear asset inspection activities generally extend from one end of the line section to the other end; rail transit linear asset inspection activities are mainly composed of activities with repetitive characteristics. For example, dynamic vehicle inspection activities are generally carried out continuously and repeatedly in multiple line sections, consuming time while continuously moving forward in mileage position.

[0060] (2) There are overlaps in the inspection items of different inspection methods. For example, the inspection items of rail inspection vehicles and rail inspection instruments include height, track direction, track gauge, level, and triangular pits; rail flaw detection vehicles, rail flaw detectors, and manual inspections all check the damage condition of rails.

[0061] (3) In order to ensure the safety of on-track personnel, some inspection activities need to be arranged during the window time, such as track inspection and rail flaw detector inspection. There are also some inspection activities that do not need to be arranged during the window time, such as track vehicle inspection, dynamic inspection vehicle inspection, and rail flaw detector vehicle inspection.

[0062] (4) There is no logical constraint on the order of inspection activities of different inspection methods in the time dimension, that is, the order of inspection activities of different inspection methods in time does not affect the perception of the track status.

[0063] (5) There are no multiple inspection activities at the same time and space mileage position. For example, when implementing rail flaw detector inspection activities, track inspection instrument inspection activities cannot be arranged at the same location at the same time.

[0064] (6) Inspection activities are affected by a variety of temporal and spatial factors. For example, in line sections where there are high-risk hidden dangers in equipment quality, the frequency of inspection activities should be increased. The inspection rate is affected by a variety of temporal and spatial factors and is uncertain.

[0065] In the embodiment of the present invention, rail transit linear asset inspection refers to the sum of a series of actions performed by applying technical means to investigate the status of rail transit linear assets. Rail transit linear asset inspection has clear time span and mileage range information, and consumes a certain amount of time and resources during its execution. An inspection activity refers to an inspection task that a working group is assigned to perform within a certain time span and mileage range.

[0066] The present invention provides an inspection plan optimization method, such as Figure 2 As shown, it includes: determining a target expression based on the decision variables of the original plan and the adjusted decision variables; determining a target function based on the target expression, wherein the target function is a target function for minimizing plan changes; and determining an inspection plan based on the target function for minimizing plan changes.

[0067] Furthermore, determining the objective function includes: determining decision variables based on the rail transit space-time grid, and determining the objective function based on the rail transit space-time grid and the decision variables; the decision variables are used to represent the execution status of the specified inspection activity in the space-time grid.

[0068] Among them, the objective function is to minimize the sum of the absolute values ​​of the decision variable differences of the rail transit space-time grid from the starting unit time of the inspection plan adjustment to the end time of the inspection plan; the sum of the absolute values ​​of the decision variable differences is determined as follows: for each inspection method of each rail transit space-time grid, determine the difference between the decision variable after the plan adjustment and the original plan value; and sum up the multiple differences obtained.

[0069] Specifically, the embodiment of the present invention uses the spatiotemporal grid of rail transit linear asset inspection as the basic unit, discretizes the rail transit linear asset inspection activities in the spatial and temporal dimensions, and proposes an optimization and adjustment model of inspection schedule for rail transit linear asset grids (OAMIS-TG), which establishes a rail transit spatiotemporal grid based on the spatial dimension of rail transit lines and the temporal dimension of rail transit linear asset inspection. The various time and space constraints and objective functions of different inspection activities of rail transit linear assets are defined in more detail, the balance and adjustability of the compiled rail transit linear asset inspection plan are optimized, and the practicality of the rail transit linear asset inspection plan is enhanced.

[0070] The following is a detailed description of the construction of the optimization and adjustment model for the grid-based inspection plan of rail transit linear assets. The subdivision of rail transit linear asset inspection activities based on space-time grids.

[0071] In the embodiment of the present invention, the rail transit lines with linear, continuous and strip layouts are divided into several small sections according to certain rules to form a rail transit grid. Without loss of generality, the line is divided into several adjacent small sections of equal length. The rail transit time-space grid refers to a number of small units formed by dividing the entire life cycle of the rail transit line facilities according to certain rules based on the two dimensions of time and space. In the embodiment of the present invention, the declaration cycle process is a complete maintenance process. Figure 3 As shown, the horizontal axis represents mileage, the vertical axis represents time, and each space-time grid is represented by G ij Indicates, i represents the i-th rail transit grid, and j represents the time period of the grid. The rail transit time-space grid is a basic unit based on time-space. Exemplarily, the rail transit time-space grid division method is as follows.

[0072] (1) Time grid division: According to the actual work requirements of rail transit infrastructure management, the entire life cycle of rail transit infrastructure can be divided into minutes, hours, days, weeks, months, and years in the time dimension. In different application scenarios, managers can choose the size of the time grid unit according to the actual scenario requirements.

[0073] (2) Spatial grid division: As the smallest unit for segmenting linear and continuous rail transit lines in the spatial dimension, the division of spatial grids should fully consider the business characteristics of the inspection activities and the management requirements of the site. In the embodiment of the present invention, the length of the rail transit grid is set to 200 meters, and the railway 100-meter mark is selected as the dividing point between adjacent grids.

[0074] Rail transit linear asset inspection activities have clear time span and mileage range information, and consume a certain amount of time and resources during their execution. Based on the space-time grid, rail transit linear asset inspection activities are divided into smaller time units and space units, which can more finely define the various time and space constraints of inspection activities, and more accurately describe the impact of various time factors and space factors on inspection activities, so that managers can manage rail transit infrastructure inspection activities at a higher time and space resolution, such as Figure 4(a) , 4(b) As shown in the figure, the horizontal axis represents the line mileage, the vertical axis represents the time of activity execution, and the broken line represents the inspection activity of rail transit infrastructure. In Figure 4(b), the angle between the broken line and the horizontal axis represents the speed of activity execution. The smaller the angle, the faster the execution rate of the corresponding activity. The shaded part in Figure 4(b) represents the spatiotemporal constraints between any time and any mileage point in the entire process of the execution of two adjacent activities.

[0075] Rail transit linear asset inspection activities may be delayed or temporarily cancelled due to various time and space factors (such as bad weather), and the rail transit linear asset inspection plan may be adjusted multiple times during actual implementation. Therefore, the embodiment of the present invention summarizes the concept of "rail transit linear asset inspection plan basic diagram", which is a graphical representation of the time and space relationship of the inspection activities using the coordinate principle, and is used to describe the start time, end time, starting mileage, and end mileage of each inspection activity of the rail transit linear asset, the order of the intervals occupied by different inspection activities, and the length of time each inspection activity occupies the interval.

[0076] During the actual implementation of the rail transit linear asset inspection plan, when the actual progress deviates from the plan, in order to prevent the entire inspection plan from being chaotic, the basic diagram of the rail transit linear asset inspection plan is adjusted with the minimum plan change as the optimal goal to ensure the orderly implementation of the inspection plan.

[0077] In order to consider the influence of various factors, the embodiment of the present invention subdivides the rail transit linear asset inspection activities in the spatial and temporal dimensions, and proposes OAMIS-TG in combination with the characteristics of rail transit linear asset inspection activities. OAMIS-TG at least includes an objective function and may also include constraints. Among them, the objective function is to minimize the plan change; the constraint system includes time constraints, construction period constraints, space constraints, rate constraints, resource constraints, inspection continuity constraints, etc.

[0078] The construction of the OAMIS-TG model is described in detail below.

[0079] The constants involved in the OAMIS-TG model are as follows:

[0080] SD represents the starting mileage of the inspection plan;

[0081] ED represents the end mileage of the inspection plan;

[0082] DR represents the mileage length of the inspection activity, and its calculation is shown in formula (1);

[0083] DR=ED-SD (1)

[0084] LE represents the length of the linear asset grid of rail transit, which is generally 200 meters;

[0085] The rail transit time-space grid and inspection activities are represented by the following method (the embodiment of the present invention does not limit the symbols represented, and other variables or symbols can be replaced):

[0086] N represents the total number of grids divided by the rail transit linear asset line, and its calculation is shown in formula (2);

[0087]

[0088] G i (i∈[1, 2, ..., N]) represents the i-th rail transit linear asset grid; i represents the sequence number of the rail transit linear asset grid;

[0089] M represents the total number of categories of rail transit linear asset inspection methods;

[0090] C j (j∈[1, 2, ..., M]) represents the jth type of inspection method; j represents the sequence number of the rail transit linear asset inspection method;

[0091] C ij (i∈[1,2,...,N],j∈[1,2,...,M]) represents the rail transit linear asset grid G i The jth type of inspection method;

[0092] E represents the total number of unit time in a planning cycle, and e represents the e-th unit time, that is, e represents the sequence number of the unit time in the planning cycle;

[0093] S ij Indicates that within a planning cycle, the linear asset grid G ​​of rail transit i Inspection method C j The inspection frequency threshold of different rail transit linear asset grids may be different due to the influence of various time and space factors.

[0094] S i Indicates that within a planning cycle, the linear asset grid G ​​of rail transit iThe total number of inspection passes for all inspection methods is calculated as follows:

[0095]

[0096] min T ij Indicates that within a planning cycle, the linear asset grid G ​​of rail transit i Inspection method C j The minimum check interval threshold;

[0097] max T ij Indicates that within a planning cycle, the linear asset grid G ​​of rail transit i Inspection method C j The maximum check interval threshold;

[0098] max L j Indicates the inspection mode C per unit time j The maximum check grid number threshold;

[0099] min L j Indicates the inspection mode C per unit time j The minimum check grid number threshold;

[0100] RC j Indicates that the execution check mode is C j Number of working groups for inspection activities;

[0101] RC represents the total number of working groups performing inspection activities.

[0102] The model OAMIS-TG involves decision variables. In the embodiment of the present invention, the decision variables are variables that determine whether to perform inspection activities of a specified inspection method in a specified unit time for a specified rail transit linear asset grid based on the rail transit space-time grid.

[0103] The decision variables of the OAMIS-TG model are This variable represents the rail transit linear asset grid G i Whether to execute the check method C at the e-th unit time j inspection activities, See formula (4). Represents the linear asset grid G ​​of rail transit i The check method executed at the e-th unit time is C j inspection activities, Represents the linear asset grid G ​​of rail transit i The check method C is not executed at the e-th unit time j inspection activities.

[0104]

[0105] For inspection method C j , the corresponding optimization problem has N×E Boolean decision variables to consider, such as Figure 5 As shown. There are M types of inspection methods for the entire model, so the model OAMIS-TG has a total of M×N×E Boolean decision variables that need to be considered. The embodiment of the present invention uses Boolean values ​​as decision variable values, which has fast calculation speed and is not prone to errors. However, the embodiment of the present invention does not limit the value-taking method of the decision variable. In other embodiments, integers and other types can also be used, so that the value is not limited to 0 and 1, as long as it can be used to calculate the changes in the inspection plan.

[0106] Determine the decision expression. The decision expression involved in the OAMIS-TG model is as follows.

[0107] Z ij Indicates that in one inspection plan preparation cycle, grid G i Inspection method C j The set of execution times of all inspection activities. Set Z ij The number of elements in is equal to the grid G i Inspection method C j The inspection pass threshold S ij . Set Z ij The elements in Represents, n∈[1, 2, ..., S ij ], Represents the grid G i In the Unit time to perform the check method C j inspection activities. and The functional relationship is shown in formula (5). Indicates the grid G i The check method C is executed at the e-th unit time j Inspection activities, at this time,

[0108] Inf means selecting elements that meet the conditions.

[0109] U i Indicates that in one inspection plan preparation cycle, grid G i The set consisting of the execution time of all inspection activities of all inspection methods. Set U i The number of elements in is equal to the grid G i The total number of inspection passes for all inspection methods is S i . Set U i The elements in Represents, n∈[1, 2, ..., S i ], Represents the grid G i In the Inspection activities were performed per unit of time. and The functional relationship is shown in formula (6). Indicates the grid G i The check method C is executed at the e-th unit time j Inspection activities, at this time,

[0110]

[0111] Q ij Represents the grid G i The execution check mode is C j The number of inspection activities is calculated as shown in formula (7).

[0112]

[0113] Indicates that the inspection method is C j The number of grids inspected in the e-th unit time of the inspection activity is calculated as shown in formula (8).

[0114]

[0115] Indicates that the execution check method for the e-th unit time is C j The demand for work groups for inspection activities is calculated as shown in formula (9). The model OAMIS-TG assumes that the inspection method is C j There is only one working group for the inspection activity. If the actual problem is for the inspection method C j If there are multiple working groups, they will be divided into multiple sub-problems of a single working group according to the inspection tasks for processing.

[0116]

[0117] Determine the objective function based on the space-time grid. The objective function of the OAMIS-TG model in the embodiment of the present invention is the objective function of minimizing planned changes.

[0118] The minimum plan change of the basic diagram of the rail transit linear asset inspection plan means that during the implementation of the rail transit linear asset inspection activities, due to the disturbance of various random factors, the inspection plan after adjustment cannot be carried out according to the original plan, and the deviation between the original plan and the adjusted inspection plan is the smallest. The model OAMIS-TG uses the change in the number of space-time grids occupied by the inspection plan before and after the adjustment as an indicator to measure the degree of change in the inspection plan. The closer the adjusted inspection plan is to the original plan and the smaller the deviation is, the smaller the impact on other work will be, and the more orderly the work on site will be.

[0119] The model OAMIS-TG adopts the adjusted plan and the original plan and The sum of the absolute values ​​of the differences defines the size of the plan change, which is calculated as shown in formula (10), i.e., the target expression. In the formula, h means that the inspection plan needs to be recompiled starting from the hth unit time.

[0120]

[0121] The objective function is to minimize the value of this expression.

[0122] Furthermore, combined with the analysis of the characteristics of rail transit linear asset inspection activities, the embodiments of the present invention also consider dividing the constraints between rail transit linear asset inspection activities into time constraints, construction period constraints, space constraints, rate constraints, resource constraints, inspection continuity constraints, etc.

[0123] If the above constraints are violated, inspection activities will be discontinuous or intermittent, which will cause waste of resources, loss of inspection efficiency and increase management costs.

[0124] In the embodiment of the present invention, the following six types of inspection activity constraints are defined more finely based on the spatiotemporal grid of rail transit linear assets: time constraints, construction period constraints, space constraints, rate constraints, resource constraints and inspection continuity constraints.

[0125] Time Constraints

[0126] like Figure 6 As shown in the figure, the time constraints of rail transit linear asset inspection activities are as follows: ① In a planning cycle, grid G i Inspection method C j The time interval between two consecutive inspections should be greater than or equal to the minimum inspection interval threshold min T ij , see formula (28); ② In a planning cycle, the grid G i Inspection method C j The time interval between two consecutive inspections should be less than or equal to the maximum inspection interval threshold max T ij, see formula (29). In an inspection plan preparation cycle, if the number of inspections specified by a certain inspection method is 1, the time constraint of the inspection activity corresponding to the inspection method is not considered. Figure 6 The horizontal axis represents the line mileage, the vertical axis represents time, and the polylines of different shapes represent inspection activities of different inspection methods. The horizontal axis is divided by grid length, and the vertical axis is divided by the time granularity required for management, forming a time-space grid for rail transit linear assets.

[0127]

[0128]

[0129] Represents the grid G i In the Unit time to perform the check method C j inspection activities, Represents the grid G i In the Unit time to perform the check method C j Inspection activities, m and m+1 are two adjacent inspections, and Represents the grid G i Inspection method C j The time between two adjacent inspections.

[0130] Violation of the maximum time constraint will result in managers being unable to promptly discover quality problems of rail transit linear assets, and violation of the minimum time constraint will result in a waste of inspection resources.

[0131] Duration Constraints

[0132] The construction period constraints of rail transit linear asset inspection activities include two aspects: ① Within a planning cycle, each type of inspection method needs to complete the specified number of inspections; ② Each type of inspection method needs to inspect all rail transit linear asset grids during each inspection to avoid missed inspections. Therefore, within a planning cycle, the grid G i The execution check mode is C j Number of inspection activities Q ij Should be equal to the threshold S of the number of inspection passes ij , see formula (30) and Figure 7 . Figure 7 The horizontal axis represents the line mileage, and the vertical axis represents the time. The horizontal axis is divided by the grid length, and the vertical axis is divided by the time granularity required for management, forming a rail transit linear asset space-time grid. The dotted line represents the deadline of the inspection plan. i＞0 , resulting in the dotted box area Q ij <Sij , the construction period constraint is not met.

[0133]

[0134] Violation of construction period constraints may cause originally risk-free rail transit linear assets to evolve into risk hazards, and the original low risk may evolve into high risk.

[0135] Space constraints

[0136] The spatial constraint of rail transit linear asset inspection activities means that at most one inspection activity can occur in any rail transit linear asset space-time grid. i At most one inspection activity can occur in a unit of time, see formula (31) and Figure 8 . Figure 8 The horizontal axis represents the line mileage, the vertical axis represents time, and lines of different shapes represent inspection activities of different inspection methods. The horizontal axis is divided into scales according to the grid length, and the vertical axis is divided according to the time granularity required for management, forming a time-space grid for rail transit linear assets.

[0137]

[0138] If the above constraints are violated, there will be temporal and spatial conflicts between inspection activities, which will affect the efficiency and safety of the inspection activities.

[0139] Rate Constraint

[0140] The OAMIS-TG model defines the inspection rate by the number of rail transit linear asset grids inspected per unit time for each type of inspection activity. Fig. 9 As shown in the figure, the rate constraints of rail transit linear asset inspection activities are as follows: ① The inspection method is C j The number of grids inspected per unit time Should be less than or equal to the maximum rate threshold max L j , see formula (32); ② The inspection method is C j The number of grids inspected per unit time Should be greater than or equal to the minimum rate threshold min L j , see formula (33). Fig. 9 The horizontal axis represents the line mileage, and the vertical axis represents time. The horizontal axis is divided according to the grid length, and the vertical axis is divided according to the time granularity required for management, forming a space-time grid for rail transit linear assets.

[0141]

[0142]

[0143] Meeting the maximum rate constraint is used to ensure inspection quality and prevent false detection and missed detection; meeting the minimum rate constraint is used to ensure the efficiency of inspection activities.

[0144] Resource Constraints

[0145] The resource constraint of rail transit linear asset inspection activity refers to the number of inspection methods C per unit time. j Number of inspection activities Less than or equal to the corresponding working group number RC j , see formula (34) and Fig.10 . Fig.10 The horizontal axis represents time, and the vertical axis represents the number of work groups. The dotted line represents the resource usage threshold RC j .

[0146]

[0147] Meeting resource constraints is the basic guarantee for the feasibility of the inspection plan. If the amount of resources used by the inspection activity exceeds the available resources, it will directly lead to the inability to organize and arrange the inspection activity.

[0148] Check continuity constraints

[0149] The continuity constraint of rail transit linear asset inspection means that each working group performs the inspection in the following way: j The inspection activities should be continuous and uninterrupted within a unit of time, see formula (35) and Fig.11 . Fig.11 The horizontal axis represents the line mileage, and the vertical axis represents time. The horizontal axis is divided by the grid length, and the vertical axis is divided by the time granularity required for management, forming a rail transit linear asset space-time grid. The dotted line represents the start and end time of the e-th unit time. i >0, the check continuity constraint is not satisfied.

[0150]

[0151] Where p represents the mileage position starting from the e-th unit time, then Indicates the mileage position where the execution of the e-th unit time ends.

[0152] If the above constraints are violated, the inspection activities will be discontinuous or intermittent, which will cause waste of resources and loss of inspection efficiency, and increase management costs. For example, for the same type of inspection activities, if it is necessary to inspect a two-kilometer line on a certain day, then according to the inspection continuity constraint, these two kilometers must be continuous and one kilometer cannot be skipped in the middle. Otherwise, the skipped mileage needs to be inspected again separately, which increases the cost of manpower and mechanical transportation and wastes resources.

[0153] This model can be used to generate adjustment optimization plans, as well as to screen or evaluate existing inspection adjustment plans. The above-mentioned spatiotemporal grid, decision variables and corresponding constraint functions can also be used to construct an inspection plan evaluation model for rail transit linear assets, which is used to scientifically evaluate the inspection plan.

[0154] When used to generate an adjustment optimization scheme, the objective function and constraints of this model can be applied to the solution software, and the adjustment optimization scheme can be automatically calculated by the solution software. Exemplarily, the solution software has a global optimal algorithm, and the embodiment of the present invention does not limit the selection of the solution software. When the inspection plan changes, the inspection plan is readjusted to generate a new inspection plan. When there are multiple inspection plan adjustment schemes, such as inspection plans compiled by engineers based on experience or generated by other planning software, the minimum objective function of the OAMIS-TG model in the embodiment of the present invention can be used for screening and testing, and the inspection plan with the smallest change relative to the original plan can be selected, and it is required to meet the constraints required by the model. Preferably, the plan with the smallest change that satisfies all the above constraints is selected. In another embodiment, a plan that satisfies some constraints can also be selected as needed. The embodiment of the present invention is based on the subdivided spatiotemporal grid and the variables executed by the inspection activities, and the inspection activities within the entire inspection cycle are carefully and comprehensively managed. The use of the minimum change objective function can reduce the negative impact caused by the plan changes and reduce the waste of inspection resources. In the embodiment of the present invention, based on fine grid division and combined with the variable definition of time, space, and inspection method, a scientific basis is provided for judging the feasibility and reliability of the plan, that is, a mathematical representation of multiple constraints. However, the embodiment of the present invention does not limit the usage of the constraint content, and constraint judgment conditions can be added or reduced as needed. At the same time, the embodiment of the present invention aims to provide an optimization scheme for adjusting the plan, and does not limit how to obtain one or more new inspection plans after the plan changes, for example, obtaining a new adjustment plan through manual planning or using a computer to automatically calculate a new adjustment plan, or a combination of the two.

[0155] The inspection plan optimization method of the embodiment of the present invention has achieved good technical effects in practical applications. The following takes the track inspection plan of the Lanxin Line down K721+000~K765+000 in December 2016 as an example to verify the effectiveness of the model OAMIS-TG proposed in the embodiment of the present invention.

[0156] Railway track is a typical linear asset of rail transit. The proposed method of preparing a linear asset inspection plan for rail transit is explained by using the preparation of a track inspection plan. The line section length DR of the Lanxin Line from K721+000 to K765+000 is 44km. The daily inspection and maintenance tasks of the engineering equipment are undertaken by the Jiayuguan Line Workshop of China Railway Lanzhou Bureau Group Co., Ltd. (hereinafter referred to as "Lanzhou Bureau"). The track grid length LE is 200 meters, so the number of track grids N involved in the Lanxin Line Downstream in this example is 220.

[0157] The total number of days in the planning cycle of this example is E=31, involving 4 types of inspection methods, namely, track inspection instrument inspection, rail flaw detection inspection, manual inspection, and track inspection vehicle inspection. Table 1 shows the inspection task volume of the Lanxin Line Downward Track of the Jiayuguan Line Workshop of Lanzhou Bureau in December 2016. Among them, the track quality status of the Lanxin Line Downward Track from K731+000 to K736+000 is poor, so the manual inspection frequency of the track grid within this mileage range is one more than that of other track grids. The track inspection vehicle inspection has been pre-arranged on the 8th and 21st, respectively, to conduct the first and second inspections of the Lanxin Line Downward Track.

[0158] Table 1 Inspection workload of the Lanzhou-Xinjiang Line Downward Track by the Jiayuguan Line Workshop of Lanzhou Bureau in December 2016

[0159]

[0160] This example involves four working groups, namely the Jiayuguan inspection and monitoring area, the Jiayuguan line maintenance area, the Jiayuguan rail flaw detection area, and the track inspection vehicle working group. In order to observe the overall distribution of the data set and identify possible outliers in the data set, 581 historical inspection rate data of these working groups in the three years from January 2015 to December 2017 were analyzed, and the first and third quartiles of the historical inspection rate data were selected as the upper and lower thresholds of the inspection rate, where the inspection rate is defined by the line length inspected within the unit skylight time. Table 2 shows the inspection rate constraints of different inspection methods on the Lanxin Line.

[0161] Table 2 Inspection rate constraints of different inspection methods on Lanxin Line

[0162]

[0163] Fig.12 The railway track inspection plan is optimized and compiled based on the above data. The horizontal axis in the figure represents the line mileage, the vertical axis represents the date, and different solid line segments are marked to represent inspection activities of different inspection methods, such as rail flaw detection inspection activities, track inspection vehicle inspection activities, track inspection instrument inspection activities, and manual inspection activities.

[0164] In order to verify the minimum plan change target of the model OAMIS-TG, with the optimized inspection plan as the background, it is assumed that the on-site engineer organized the inspection activities according to the inspection plan, and counted the execution of the track inspection activities in the mileage range of the Lanxin Line on December 14, 2016. The remaining tasks of the inspection activities are shown in Table 3. Compared with the original plan, there are the following deviations in the actual implementation: ① The rail flaw detection inspection activities in the range of K751+000~K758+000 of the Lanxin Line were not carried out as planned; ② The manual inspection activities in the range of K735+000~K736+000 of the Lanxin Line were not carried out as planned; ③ The track inspection instrument inspection activities in the range of K750+000~K751+000 of the Lanxin Line were not carried out as planned. A total of 9 kilometers of track lines were not carried out according to the original inspection plan. The readjusted track inspection plan will cause at least 45 track space-time grid occupancy changes. Therefore, the ideal maximum value of the objective function corresponding to this practical problem is 45.

[0165] Table 3 The remaining tasks of the Lanzhou-Xinjiang Line down track inspection by the Jiayuguan Line Workshop of Lanzhou Railway Bureau in December 2016

[0166]

[0167] The model OAMIS-TG is used to adjust the unexecuted inspection tasks in the basic diagram of the railway track inspection plan to ensure the minimum change in the plan. After calculation, the minimum target of the plan change A = 45, and the corresponding objective function value is -45, which has reached the ideal maximum value.

[0168] Fig.13 (a) is the basic diagram of the track grid inspection plan initially compiled by the OAMIS-TG model. Fig.13 (b) is the basic diagram of the adjusted track inspection plan. In the diagram, the horizontal axis represents the line mileage, the vertical axis represents the date, and different solid line segments are marked to represent inspection activities of different inspection methods, such as rail flaw detection inspection activities, track inspection vehicle inspection activities, track inspection instrument activities, and manual inspection activities. The virtual box marks the changed part of the inspection plan. By comparison Fig.13 As can be seen from (a) and (b) in the figure, the adjusted inspection plan basic diagram has little change compared to the initial basic diagram.

[0169] Therefore, the OAMIS-TG model proposed in the embodiment of the present invention can minimize the change compared with the original plan when the inspection plan needs to be adjusted, thereby ensuring the guidance of the inspection plan.

[0170] Based on the same inventive concept, an embodiment of the present invention further provides a method for evaluating an inspection plan for rail transit linear assets, comprising:

[0171] Establish a rail transit space-time grid based on the spatial dimension of rail transit lines and the temporal dimension of rail transit linear asset inspection;

[0172] The grid inspection plan evaluation model for rail transit linear assets is determined based on the rail transit space-time grid, including:

[0173] Determining a decision variable based on the rail transit space-time grid, wherein the decision variable is used to represent the execution status of the specified inspection activity in the space-time grid;

[0174] Determine constraints based on rail transit space-time grid and decision variables;

[0175] The inspection plan is determined based on the grid inspection plan evaluation model for rail transit linear assets.

[0176] The inspection plan evaluation method for rail transit linear assets of the embodiment of the present invention can screen and evaluate the rationality of the inspection plan through an evaluation model with constraints when formulating or optimizing the inspection plan, thereby improving the scientificity and efficiency of the plan evaluation.

[0177] Furthermore, the constraint condition includes at least one of the following constraint conditions: time constraint, duration constraint, space constraint, rate constraint, resource constraint, and inspection continuity constraint. Some or all of the constraints can be selected as needed to construct the evaluation model.

[0178] The specific expression of the model construction process and constraints based on space-time grids and decision variables can be obtained from the above-mentioned embodiments related to the optimization and adjustment model of the rail transit linear asset grid inspection plan, and will not be repeated here.

[0179] Based on the same inventive concept, the embodiment of the present invention also provides an inspection plan optimization system, such as Fig.14 As shown, the system includes: a target determination unit, used to determine the target expression based on the decision variables of the original plan and the adjusted decision variables; an objective function determination unit, used to determine the objective function based on the target expression, wherein the objective function is a plan change minimum objective function; and an inspection plan determination unit, which determines the inspection plan according to the plan change minimum objective function.

[0180] The specific implementation of the inspection plan optimization system of the embodiment of the present invention can be obtained according to any embodiment method of the present invention and will not be described in detail.

[0181] The method of the present invention can be implemented by a system controlled by a computer or an embedded program. Therefore, correspondingly, an inspection plan optimization device is also provided in an embodiment of the present invention, such as Fig.15As shown, the device includes at least one processor and at least one memory; the memory stores a computer program for executing the method of any embodiment of the present invention, and the processor calls the computer program in the memory to execute the method of any embodiment of the present invention.

[0182] Furthermore, the memory may be communicatively connected to one or more processors, and the memory may store instructions that may be executed by one or more processors. The instructions are executed by one or more processors so that the one or more processors can implement the method of the present invention.

[0183] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent substitutions for some of the technical features therein; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for optimizing an inspection plan, characterized in that: include: The target expression is determined based on the decision variables of the original plan and the adjusted decision variables; wherein the decision variable is a variable that determines whether to perform an inspection activity of a specified inspection method in a specified unit time for a specified rail transit linear asset grid based on the rail transit time-space grid; the decision expression is: ； ； ； ； ； in, Representation Grid In the The inspection method is performed in units of time. Inf means selecting elements that meet the conditions; Representation Grid In the Units of time were used to perform inspection activities; Representation Grid The execution check method is Number of inspection activities; Indicates the inspection method is The number of grids inspected in the e-th unit time by the inspection activity; Indicates that the check method for the e-th unit time is The number of working groups required for inspection activities; (i∈[1, 2, ..., N]) represents the i-th rail transit linear asset grid; i represents the sequence number of the rail transit linear asset grid; (j∈[1, 2, ..., M]) represents the jth type of inspection method; j represents the sequence number of the rail transit linear asset inspection method; The objective function is determined based on the objective expression, wherein the objective function is the objective function of minimizing planned changes; the objective function is the objective expression A with the minimum value, in, is the decision variable of the original plan, The adjusted decision variable, h, indicates that the inspection plan needs to be re-compiled starting from the hth unit of time; Among them, the decision variables Indicates whether the i-th rail transit linear asset grid performs the inspection activity of the j-th inspection method in the e-th unit time, N represents the total number of grids divided by the rail transit linear asset line, M represents the total number of categories of rail transit linear asset inspection methods, E represents the total number of unit times in a planning cycle, and e represents the e-th unit time; The inspection plan is determined based on the objective function of minimizing plan changes.

2. The inspection plan optimization method according to claim 1, characterized in that: Determining the objective function includes: Determine decision variables based on the rail transit space-time grid, and determine the objective function based on the rail transit space-time grid and the decision variables; The decision variables are used to represent the execution status of the specified inspection activities in the space-time grid.

3. The inspection plan optimization method according to claim 2, characterized in that: The objective function is to minimize the sum of the absolute values ​​of the decision variable differences of the rail transit space-time grid from the start unit time of the inspection plan adjustment to the end time of the inspection plan; The method for determining the sum of the absolute values ​​of the decision variable differences is: for each inspection method of each rail transit space-time grid, determine the difference between the decision variable after the plan adjustment and the original plan value; and sum the multiple differences obtained.

4. An inspection plan optimization system, characterized in that: include: The target determination unit is used to determine the target expression based on the original decision variables and the adjusted decision variables; wherein the decision variable is a variable that determines whether to perform an inspection activity of a specified inspection method in a specified unit time for a specified rail transit linear asset grid based on the rail transit time-space grid; the decision expression is: ； ； ； ； ； in, Representation Grid In the The inspection method is performed in units of time. Inf means selecting elements that meet the conditions; Representation Grid In the Units of time were used to perform inspection activities; Representation Grid The execution check method is Number of inspection activities; Indicates the inspection method is The number of grids inspected in the e-th unit time by the inspection activity; Indicates that the check method for the e-th unit time is The number of working groups required for inspection activities; (i∈[1, 2, ..., N]) represents the i-th rail transit linear asset grid; i represents the sequence number of the rail transit linear asset grid; (j∈[1, 2, ..., M]) represents the jth type of inspection method; j represents the sequence number of the rail transit linear asset inspection method; An objective function determination unit is used to determine an objective function based on the objective expression, wherein the objective function is an objective function that minimizes planned changes; the objective function is an objective expression A that takes a minimum value, in, is the decision variable of the original plan, The adjusted decision variable, h, indicates that the inspection plan needs to be re-compiled starting from the hth unit of time; Among them, the decision variables Indicates whether the i-th rail transit linear asset grid performs the inspection activity of the j-th inspection method in the e-th unit time, N represents the total number of grids divided by the rail transit linear asset line, M represents the total number of categories of rail transit linear asset inspection methods, E represents the total number of unit times in a planning cycle, and e represents the e-th unit time; The inspection plan determination unit determines the inspection plan based on the objective function of minimizing plan changes.

5. The inspection plan optimization system according to claim 4, characterized in that: The objective function determination unit determines the objective function including: Determine decision variables based on the rail transit space-time grid, and determine the objective function based on the rail transit space-time grid and the decision variables; The decision variables are used to represent the execution status of the specified inspection activities in the space-time grid.

6. The inspection plan optimization system according to claim 5, characterized in that: The objective function is to minimize the sum of the absolute values ​​of the decision variable differences of the rail transit space-time grid from the start unit time of the inspection plan adjustment to the end time of the inspection plan; The method for determining the sum of the absolute values ​​of the decision variable differences is: for each inspection method of each rail transit space-time grid, determine the difference between the decision variable after the plan adjustment and the original plan value; and sum the multiple differences obtained.

7. An inspection plan optimization device, characterized in that: The apparatus comprises at least one processor and at least one memory; The memory stores a computer program for executing any one of the methods of claims 1 to 3, and the processor calls the computer program in the memory to execute any one of the methods of claims 1 to 3.

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