Maintenance resource dynamic preemptive maintenance scheduling method

Abstract

The invention discloses a dynamic preemptive maintenance scheduling method for maintenance resources, relates to the technical field of health management, and aims to sort and schedule tasks through final evaluation indexes, reasonably utilize existing maintenance resources to allocate maintenance tasks, properly consider resource preemption and maximize maintenance strength. The task success rate is improved, and high-efficiency maintenance scheduling is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of health management, and in particular to a dynamic preemptive maintenance scheduling method for maintenance resources. Background Art

[0002] While the development of science and technology drives industrial development, it also affects the form of modern warfare. Modern warfare is gradually moving towards unmanned and information-based warfare. In information-based warfare, time is a key factor affecting the direction of war. The battlefield situation changes rapidly, and having a time advantage can take the lead and take the initiative. Due to the uncertainty of the battlefield situation, as the war progresses, various problems will inevitably arise in the equipment. How to restore the combat effectiveness of the equipment as much as possible within limited resources and limited time has become a key issue affecting the success rate of wartime missions.

[0003] So far, most scholars have studied static scheduling problems, and there are few studies on preemptive scheduling problems, and the research is not in-depth. Since wartime maintenance tasks are uncertain, it is inevitable that more important tasks will appear later. In order to improve the success rate of tasks, preemptive scheduling is undoubtedly more suitable for wartime maintenance needs. As the war continues to advance, due to different mission locations, different equipment or even the same type of equipment may perform tasks at different locations. Therefore, when a failure occurs, the equipment may be scattered all over the battlefield, so the location of the maintenance task is uncertain. Depending on the task, the maintenance parts required for wartime faulty equipment will also be different. Some parts do not need to be repaired during wartime and can be repaired after the war. In addition, according to the equipment failure situation, combined with the current maintenance resources, the maintenance resources and maintenance time required to repair to normal combat and emergency combat will also be different, and the corresponding equipment importance will also be different. The maintenance resources required for maintenance tasks are limited resources, and reasonable planning of maintenance resources should be made according to actual conditions. During the maintenance process, as the physical strength of maintenance personnel will continue to decline, the corresponding maintenance efficiency will also decline, and the maintenance efficiency will also affect the maintenance time of maintenance tasks. In addition, maintenance time will also be affected by the distance between the maintenance task location and the maintenance force.

[0004] From the above analysis, it can be seen that there are many conditions that affect the scheduling of maintenance tasks, and the corresponding scheduling model is relatively complex. In addition, during the maintenance process, due to limited maintenance resources, it is difficult to avoid the phenomenon of maintenance resource preemption. Not considering resource preemption may delay the maintenance process of important equipment, thereby affecting the success rate of the task; excessive consideration of resource preemption will cause a large amount of waste of maintenance resources, which will also affect the success rate of the task. How to reasonably use existing maintenance resources to allocate maintenance tasks, appropriately consider resource preemption, maximize the role of maintenance forces, and thus improve the success rate of tasks is a key issue in the study of wartime maintenance scheduling, and is also the research content of this invention. Summary of the invention

[0005] In view of this, the present invention proposes a dynamic preemptive maintenance scheduling method for maintenance resources, which sorts and schedules tasks through final evaluation indicators to achieve efficient maintenance scheduling.

[0006] A maintenance resource dynamic preemptive maintenance scheduling method comprises the following steps:

[0007] Step 1: Set up a maintenance task library and add the tasks to be maintained to the maintenance task library;

[0008] Step 2: Based on the entropy weight topsis method, all maintenance tasks in the maintenance task library are evaluated to obtain the final evaluation index of each maintenance task, and maintenance is started in order from high to low according to the final evaluation index;

[0009] Step 3, determine whether the duration of all maintenance tasks is greater than the set total duration or is 0. If it is greater than or the duration of all maintenance tasks is 0, then end all current maintenance tasks, otherwise execute step 4;

[0010] Step 4, determine whether there is resource competition in the current maintenance task scheduling, if yes, execute step 5, otherwise, execute step 2 again;

[0011] Step 5, determine whether the resources occupied by the current maintenance task meet the resource requirements of the task to be maintained, if not, execute step 2, otherwise execute step 6;

[0012] Step 6, compare the objective function values ​​of the task under maintenance and the task to be maintained. If the priority difference between the two is less than 10% and the remaining maintenance time is not less than 60%, execute step 7, otherwise execute step 2;

[0013] Step 7: Stop the tasks under maintenance whose final evaluation index is lower than the tasks to be maintained and return the maintenance resources according to the progress, and then carry out the tasks to be maintained.

[0014] Furthermore, the objective function value is calculated as follows:

[0015] If there are m tasks in the scheduling task library at the same time, a matrix is ​​constructed based on the number of tasks and evaluation indicators.

[0016]

[0017] Among them, x io is the oth evaluation indicator of the i-th task, where i=1,2,...,m,o=1,2.

[0018] The elements of the probability matrix can be calculated as follows:

[0019]

[0020] The entropy value of the oth evaluation index is obtained by the following formula:

[0021]

[0022] Information utility value d o and entropy weight w o Calculate according to the following formula

[0023]

[0024] Find the corresponding maximum and minimum values ​​in each index as the positive and negative ideal values ​​R respectively. + and R - , as shown below

[0025]

[0026] According to the positive and negative ideal values, the distance between each indicator and it is calculated and recorded as D i + and D i - , which is expressed as follows

[0027]

[0028] The final evaluation index C is calculated as follows:

[0029]

[0030] Furthermore, the duration of the maintenance task is calculated as follows:

[0031]

[0032] Where, T fi represents the duration of the ith maintenance task, T ri represents the travel time to the destination of the i-th maintenance task, t i represents the estimated maintenance time of the ith maintenance task, E i represents the maintenance efficiency of the i-th maintenance task.

[0033] Furthermore, the returning of maintenance resources includes: returning all occupied maintenance equipment, and returning the remaining number of maintenance spare parts in proportion to the maintenance progress, wherein the remaining number of maintenance spare parts is rounded up if it is a decimal.

[0034] Furthermore, the T ri The calculation is as follows:

[0035] (x1, y1) and (x2, y2) represent the coordinates of the departure and destination of the maintenance task respectively, and v is the driving speed in km / h.

[0036] Beneficial effects:

[0037] First, this method is a dynamic preemptive maintenance scheduling method for maintenance resources, which comprehensively considers the maintenance location, importance of maintenance equipment, maintenance resources, maintenance efficiency and maintenance time, and after multiple judgments, based on the duration, resource competition and whether the resources meet the subsequent tasks, ensures the effectiveness and scientificity of the judgment, and can be effective.

[0038] Second, by evaluating all maintenance tasks in the maintenance task library based on the entropy weight topsis method to obtain the final evaluation index of each maintenance task, and sorting the maintenance tasks, it can ensure the accuracy and scientificity of maintenance task scheduling and provide a more scientific reference for actual scheduling tasks.

[0039] Third, this method provides a template for solving practical problems in the form of a mathematical model, which is easy to implement, highly reproducible, and has high practical value. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 This is an overall flow chart of the dynamic preemptive scheduling model according to an embodiment of the present invention. DETAILED DESCRIPTION

[0041] The present invention is described in detail below with reference to the accompanying drawings and embodiments.

[0042] The present invention proposes a maintenance resource dynamic preemptive maintenance scheduling method. Through the scheduling method, the maintenance location, maintenance equipment importance, maintenance resources, maintenance efficiency and maintenance time are comprehensively considered, and reasonable scheduling of dynamic preemptive maintenance resources can be achieved.

[0043] For the convenience of explanation, the scheduling model is transformed into a dynamic preemptive scheduling method for multiple maintenance vehicles for wartime maintenance tasks. The model establishment process can be described as follows:

[0044] 1. Scheduling Model Assumptions

[0045] To facilitate subsequent model construction and solution, some assumptions need to be made on the scheduling model, as follows:

[0046] (1) It is assumed that all maintenance teams have the same maintenance capabilities, regardless of maintenance tasks or personal experience;

[0047] (2) Assume that all maintenance processes are carried out smoothly and there is no problem of extended maintenance time due to maintenance errors;

[0048] (3) Assume that the maintenance team travels at a constant speed and in a straight line between two points when going to each maintenance location;

[0049] (4) It is assumed that the maintenance team will stay on standby after completing the current maintenance task, or will go directly to the next maintenance task;

[0050] (5) Assume that a maintenance task allows at most one maintenance team to carry out maintenance.

[0051] 2. Scheduling model construction

[0052] From the above analysis, it can be seen that the factors affecting the scheduling plan mainly include the maintenance location, importance of maintenance equipment, maintenance resources, maintenance efficiency and maintenance time, so the present invention mainly studies the above-mentioned influencing factors respectively.

[0053] 2.1 Repair location

[0054] The two maintenance tasks are located at different locations, so the vehicle travel time will also be different. Assuming that the location coordinates of maintenance task 1 are A(x1,y1) and the location coordinates of maintenance task 2 are B(x2,y2), the time taken by the maintenance team to travel from point A to point B can be expressed as

[0055]

[0056] Where v is the driving speed of the maintenance team vehicle, in km / h.

[0057] 2.2 Importance of maintenance equipment

[0058] The same faulty equipment can have two maintenance plans according to the actual situation, namely, maintenance to normal operation and emergency operation. The equipment importance corresponding to the two plans is different, and the required maintenance resources are also different. The equipment importance corresponding to the maintenance to normal operation is high, and the required maintenance resources are also more, while the opposite is true for the maintenance to emergency operation. The equipment importance corresponding to the two maintenance plans can be expressed as S Ni and S Ei , where i represents the i-th maintenance equipment.

[0059] 2.3 Maintenance resources

[0060] Maintenance resources can generally be divided into maintenance personnel (in this invention, the maintenance team is used as the unit), maintenance equipment and maintenance spare parts. The first two items are non-consumable resources, which can be released after the current task is completed and can be used to participate in subsequent maintenance tasks; the latter item is a consumable resource, which will be consumed after the current task is completed and cannot be used to participate in subsequent maintenance tasks. The maintenance resources must meet the following conditions: the number of maintenance teams participating in maintenance at the same time cannot exceed the total number of maintenance teams; each type of maintenance equipment participating in maintenance at the same time cannot exceed the total number of corresponding maintenance equipment; each type of maintenance spare parts participating in maintenance cannot exceed the total number of corresponding maintenance spare parts. It can be expressed specifically as follows:

[0061] L Max ≤L

[0062] N ij ≤N j

[0063] M kt ≤M kT

[0064] Where, L Max represents the number of maintenance teams participating in maintenance at the same time, L represents the total number of maintenance teams at the same time; N ij N represents the number of the jth type of maintenance equipment required for the i-th maintenance task. j represents the total number of the jth type of maintenance equipment; M kt represents the total number of spare parts of the kth category involved in maintenance, M kT Represents the total number of the kth type of maintenance spare parts owned by the maintenance resources.

[0065] 2.4 Maintenance efficiency

[0066] The maintenance efficiency depends on the physical strength of the maintenance team members. As the maintenance tasks are carried out continuously, the physical strength of the maintenance team members will inevitably decline, and the corresponding maintenance efficiency of the team will also decline accordingly; when the maintenance team drives to the location of the maintenance task, since there is no physical consumption and they can rest properly, the corresponding maintenance efficiency of the team will increase accordingly. In order to quantify the rise and fall of the maintenance efficiency of the maintenance team, half an hour is taken as the minimum unit that causes the maintenance efficiency of the maintenance team to change (less than half an hour is ignored), that is, every half an hour of maintenance task, the maintenance efficiency decreases by 5%, and every half an hour of driving, the maintenance efficiency increases by 5%. Since the calculation of maintenance efficiency during the maintenance task is relatively complicated, in order to simplify the calculation, it is assumed that the maintenance efficiency remains unchanged in a single maintenance task, and the maintenance efficiency is only calculated before and after the maintenance task is completed. Considering the actual situation, the maintenance efficiency should vary between 0 and 100%, and cannot exceed this range. The maintenance efficiency before the first maintenance task is 100%. If the current task is preempted, the maintenance efficiency of the maintenance team can be calculated according to the consumption time corresponding to the maintenance progress.

[0067] 2.5 Maintenance time

[0068] The actual maintenance time of a maintenance task is affected by many factors, including the travel time of the maintenance team to the maintenance task destination, the change in maintenance efficiency, and the estimated maintenance time of the maintenance task. The actual maintenance time can be expressed as

[0069]

[0070] Where, T fi represents the actual maintenance time of the ith maintenance task, T ri represents the driving time of the vehicle to the destination of the i-th maintenance task, t i represents the estimated maintenance time of the ith maintenance task, E i represents the maintenance efficiency of the i-th maintenance task.

[0071] 2.6 Objective Function

[0072] The goal of the wartime maintenance mission is mainly to use limited resources to quickly repair faulty equipment and return it to the battlefield quickly. Therefore, the three main factors that affect the wartime maintenance mission objective function are the total number of repaired equipment, the total importance of repaired equipment, and the secondary combat time of repaired equipment. The more the total number of repaired equipment, the more equipment can return to the battlefield, and the mission success rate will increase; the higher the total importance of repaired equipment, it means that more important equipment for the mission can be repaired, and the mission success rate will also increase; the longer the secondary combat of repaired equipment, it means that the equipment will play a role on the battlefield for a longer time, and the mission success rate will also increase. Therefore, from the above analysis, it can be seen that the final wartime maintenance objective function can be expressed as

[0073] F=w1F1+w2F2+w3F3

[0074] In the formula, F is the wartime objective function, F1 is the total number of repaired equipment, F2 is the total importance of repaired equipment, F3 is the secondary combat time of repaired equipment, w1, w2, and w3 are the weights of the three variables, and their sum is 1. The secondary combat time of repaired equipment needs to be normalized because the direct calculation time value is large, as shown below

[0075]

[0076] In the formula, t Li represents the secondary combat time of the ith maintenance equipment, T L Indicates the total maintenance time allowed during wartime.

[0077] The secondary combat time of the i-th maintenance equipment is calculated as follows:

[0078] t Li =T L -Tfi

[0079] In order to meet the wartime maintenance needs, the maintenance time should also meet the following conditions:

[0080] T F ≤T L

[0081] Where, T F Indicates the actual total time taken for the maintenance task.

[0082] 2.7 Evaluation of dynamic task scheduling model based on entropy weight TOPSIS method

[0083] The entropy weight TOPSIS method combines the objectivity of the entropy weight method and the ranking characteristics of TOPSIS. It can obtain the objective weights of each part of the objective function, and can reasonably evaluate and sort the multi-task objective functions to obtain the optimal scheduling plan. The specific process can be shown as follows.

[0084] For a single scheduling task, F1 is a fixed value, so it can be temporarily ignored in the evaluation. The weighting and evaluation are mainly focused on F2 and F3.

[0085] Assuming that there are m tasks involved in a single scheduling task, the matrix can be constructed based on the number of tasks and evaluation indicators

[0086]

[0087] In the formula, x io is the oth evaluation index of the i-th task, that is, the objective function, where i=1,2,...,m,o=1,2.

[0088] The elements of the probability matrix can be calculated as follows:

[0089]

[0090] Then the entropy value of the oth evaluation index can be obtained as follows:

[0091]

[0092] Information utility value d o and entropy weight w o Can be calculated as follows

[0093]

[0094] Find the corresponding maximum and minimum values ​​in each index as the positive and negative ideal values ​​R respectively. + and R - , as shown below

[0095]

[0096] According to the positive and negative ideal values, the distance between each indicator and it is calculated and recorded as and It can be expressed as follows

[0097]

[0098] Then the final evaluation index C can be calculated as follows

[0099]

[0100] Finally, according to C i The values ​​are sorted by size. A large value means that the objective function corresponding to the task is large, so the task will be repaired first.

[0101] 2.8 Maintenance Task Preemption Strategy

[0102] As the war progresses, maintenance resources become increasingly scarce. When a high-importance equipment failure occurs, in order to maximize the use of wartime maintenance resources, it is necessary to appropriately preempt maintenance tasks. Too much or too little preemption of maintenance tasks will affect the ultimate mission success rate, so it is necessary to conduct corresponding research on preemption strategies. The specific preemption strategies are as follows:

[0103] (1) Under the premise of sufficient maintenance resources, if there are multiple maintenance tasks at the same time, the objective functions of all maintenance tasks are calculated, and maintenance tasks with high objective function values ​​are prioritized;

[0104] (2) After the maintenance task is preempted, all maintenance equipment occupied by the current maintenance task will be returned, and maintenance spare parts will be returned in proportion to the maintenance progress (if the quantity is a decimal, it will be rounded up);

[0105] (3) If there is a resource competition phenomenon during maintenance, the first thing to do is to determine whether the sum of the returned maintenance resources and the remaining maintenance resources can meet the resources required by the maintenance task if the maintenance task is terminated;

[0106] (4) If (2) is satisfied, the maintenance objective function of the task to be maintained is calculated by formula (6). If the maintenance objective function of the task to be maintained exceeds the objective function of the task under maintenance by 10% (including 10%), and the remaining maintenance time of the task under maintenance is not less than 60%, the maintenance resources occupied by the task under maintenance shall be stopped immediately, and the maintenance resources required by the task to be maintained shall be transported to the area of ​​the equipment to be maintained, and the maintenance task shall be carried out immediately on the equipment to be maintained; if not, the original scheduling plan shall not be changed, and the task to be maintained shall be placed in the maintenance queue;

[0107] (5) If there are multiple maintenance tasks that satisfy the preemption strategy at the same time, the maintenance task with the smallest objective function value is limited to preemption;

[0108] (6) All maintenance tasks can be preempted, but each maintenance task can only be preempted once at most, and the preempted tasks will be given priority when maintenance resources are idle;

[0109] Specifically, the operation logic is as follows Figure 1 As shown, the specific steps are as follows:

[0110] Step 1: Set up a maintenance task library and add the tasks to be maintained to the maintenance task library;

[0111] Step 2: Based on the entropy weight topsis method, all maintenance tasks in the maintenance task library are evaluated to obtain the final evaluation index of each maintenance task, and maintenance is started in order from high to low according to the objective function value;

[0112] Step 3, determine whether the duration of all maintenance tasks is greater than the set total duration, if so, terminate all current maintenance tasks, otherwise execute step 4;

[0113] Step 4, determine whether there is resource competition in the current maintenance task scheduling, if yes, execute step 5, otherwise, execute step 2 again;

[0114] Step 5, determine whether the resources occupied by the task currently under maintenance meet the resource requirements of the task to be maintained, if not, execute step 2, otherwise execute step 6;

[0115] Step 6, compare the objective function values ​​of the task under maintenance and the task to be maintained. If the priority difference between the two is less than 10% and the remaining maintenance time is not less than 60%, execute step 7, otherwise execute step 2;

[0116] Step 7: Stop the tasks in maintenance whose objective function values ​​are lower than the tasks to be maintained and return the maintenance resources according to the progress, and then carry out the tasks to be maintained.

[0117] In summary, the above are only preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A maintenance resource dynamic preemptive maintenance scheduling method, characterized in that: The steps include: Step 1: Set up a maintenance task library and add the tasks to be maintained to the maintenance task library; Step 2: Based on the entropy weight topsis method, all maintenance tasks in the maintenance task library are evaluated to obtain the final evaluation index of each maintenance task, and maintenance is started in order from high to low according to the objective function value; Step 3, determine whether the duration of all maintenance tasks is greater than the set total duration or is 0. If it is greater than or the duration of all maintenance tasks is 0, then end all current maintenance tasks, otherwise execute step 4; Step 4, determine whether there is resource competition in the current maintenance task scheduling, if yes, execute step 5, otherwise, execute step 2 again; Step 5, determine whether the resources occupied by the current maintenance task meet the resource requirements of the task to be maintained, if not, execute step 2, otherwise execute step 6; Step 6, compare the objective function values ​​of the task under maintenance and the task to be maintained. If the priority difference between the two is less than 10% and the remaining maintenance time is not less than 60%, execute step 7, otherwise execute step 2; Step 7: Stop the tasks in maintenance whose objective function values ​​are lower than the tasks to be maintained and return the maintenance resources according to the progress, and then carry out the tasks to be maintained.

2. The method according to claim 1, characterized in that The objective function value is calculated as follows: If there are m tasks in the scheduling task library at the same time, a matrix is ​​constructed based on the number of tasks and evaluation indicators. Among them, x io is the oth evaluation indicator of the i-th task, where i=1,2,...,m,o=1,2. The elements of the probability matrix can be calculated as follows: The entropy value of the oth evaluation index is obtained by the following formula: Information utility value d o and entropy weight w o Calculate according to the following formula Find the corresponding maximum and minimum values ​​in each index as the positive and negative ideal values ​​R respectively. + and R - , as shown below According to the positive and negative ideal values, the distance between each indicator and it is calculated and recorded as and It is expressed as follows The final evaluation index C is calculated as follows:

3. The method according to claim 1, characterized in that The duration of the maintenance task is calculated as follows: Where, T fi represents the duration of the ith maintenance task, T ri represents the travel time to the destination of the i-th maintenance task, t i represents the estimated maintenance time of the ith maintenance task, E i represents the maintenance efficiency of the i-th maintenance task.

4. The method according to any one of claims 1 to 3, characterized in that: The returning of maintenance resources includes: returning all occupied maintenance equipment, and returning the remaining number of maintenance spare parts in proportion to the maintenance progress, wherein if the remaining number of maintenance spare parts is a decimal, it is rounded up according to the rounding up method.

5. The method according to claim 2, characterized in that The T ri The calculation is as follows: (x1, y1) and (x2, y2) represent the coordinates of the departure and destination of the maintenance task respectively, and v is the driving speed in km / h.

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