CN111176230B

CN111176230B - Mixed scheduling system and method under uncertain fault condition

Info

Publication number: CN111176230B
Application number: CN201911328908.4A
Authority: CN
Inventors: 姚敏; 廖春泉; 王治泉; 冯毅萍; 张劲松; 彭泽栋; 方明; 金炫智; 武东升; 应天裕
Original assignee: Zhejiang University ZJU; National Energy Group Ningxia Coal Industry Co Ltd
Current assignee: Zhejiang University ZJU; National Energy Group Ningxia Coal Industry Co Ltd
Priority date: 2019-12-20
Filing date: 2019-12-20
Publication date: 2022-12-06
Anticipated expiration: 2039-12-20
Also published as: CN111176230A

Abstract

The embodiment of the invention provides a mixed scheduling system and a method under the condition of uncertain faults, belonging to the technical field of production scheduling, wherein the system comprises a coordination control module, a correction type scheduling module and a rescheduling module, and the coordination control module comprises: the inventory monitoring unit is configured to acquire the current actual production quantity of each material in real time; the inventory analysis unit is configured to acquire and determine a fault unit according to the current actual production capacity of each material and the current predicted production capacity of each material; the rule selection unit is configured to call the rescheduling module when the number of the fault units is larger than a first threshold value; and when the number of the fault units is smaller than a first threshold value, judging whether the predicted execution time of the modified scheduling is larger than the production scheduling period, if so, calling a rescheduling module, otherwise, calling the modified scheduling module. The method organically combines modified scheduling and rescheduling, and has the advantages of good uncertainty resistance effect and low calculation capability requirement.

Description

Mixed scheduling system and method under uncertain fault condition

Technical Field

The invention relates to the technical field of production scheduling, in particular to a hybrid scheduling system under a fault uncertain condition and a hybrid scheduling method under the fault uncertain condition.

Background

The production scheduling control system is a basic and core module of the manufacturing system, and the excellent scheduling control system can improve the enterprise efficiency, reduce the enterprise cost and improve the product delivery date satisfaction rate. In an actual production process, the addition of fault uncertainty can affect the performance of the production system.

The scheduling control system under the uncertain environment proposed at present can be divided into two categories: prediction is made in advance and reaction is made afterwards. Before a dispatching plan is made, influence of uncertain factors or emergencies is considered in advance to enhance the anti-interference capability of the dispatching plan, namely a proactive dispatching strategy; in the process of executing the scheduling plan, the scheduling plan is corrected or adjusted to deal with uncertain factors or emergencies, and then the scheduling plan is a reactive scheduling strategy. Common specific production scheduling schemes include four types: and correcting scheduling and rolling rescheduling in optimized analysis and robust scheduling and reactive scheduling in proactive scheduling.

The analysis after optimization is to carry out optimization solution according to the existing model, select a scheme with a better target value and carry out various performance analyses on the scheme. The conclusion of such methods requires either a detailed mathematical description of the optimal solution or knowledge of the detailed trajectory of the solution during the optimization process, on the basis of which a mathematical analysis is performed. But also assumes that an optimal solution can be found. However, most scheduling problems cannot satisfy such conditions, and only a sub-optimal solution of the problem can be obtained.

The robust scheduling is to consider various uncertainties generated in the production process, the influence on the objective function of the scheduling problem is different, and when the scheduling scheme is formulated, the contradiction between the optimization of the objective function and the robustness of the scheduling scheme is comprehensively considered according to the uncertainties generated in the production process, so that the scheduling scheme with robustness is formulated. Sufficient knowledge of the uncertainty is required to achieve better results.

The modified scheduling is to dynamically modify the initial scheduling according to actual conditions after an uncertain event occurs. Its scheduling capability is limited and in some cases it is not possible to cope with the occurring uncertainty.

The rolling rescheduling is to divide the dynamic scheduling process into a plurality of continuous and static scheduling intervals, and then optimize each scheduling interval to achieve the optimal scheduling interval. The interval is divided, so that the scheduling scheme can adapt to complex and changeable dynamic environments. The rescheduling driving rule has complete dependence on the relation between production workshops and uncertain rules, and the universality is poor. And when the system runs, a scheduling result is obtained according to the optimal solution in each interval, and the rolling scheduling scheme has poor global property. In addition, frequent rescheduling also reduces system stability and increases computational resource consumption.

Disclosure of Invention

The embodiment of the invention aims to provide a hybrid scheduling system under a fault uncertain condition and a hybrid scheduling method under the fault uncertain condition, so as to solve the problems that the scheduling capability of the existing modified scheduling is limited, the requirement on computing resources for rescheduling is high, and the scheduling system is easy to be unstable.

In order to achieve the above object, in a first aspect of the present invention, a hybrid scheduling system under a fault uncertainty condition is provided, including a coordination control module, a modified scheduling module, and a rescheduling module, where the coordination control module includes:

an inventory monitoring unit configured to obtain a current actual production amount of each material in real time;

the inventory analysis unit is configured to obtain the current predicted production capacity of each material, and determine a fault unit according to the current actual production capacity of each material and the current predicted production capacity of each material;

a rule selection unit configured to invoke the rescheduling module when the number of the faulty units is greater than a first threshold; when the number of the fault units is smaller than the first threshold value, judging whether the predicted execution time of the modified scheduling is larger than or equal to the production scheduling period: if so, calling the rescheduling module, otherwise, calling the modified scheduling module;

the modified scheduling module is used for executing the modified scheduling when being called; and predicting the execution time, wherein the rescheduling module is used for executing rescheduling when being called.

Optionally, the system further comprises:

and the static scheduling module is used for generating the reference production rate of each material and calculating the predicted production capacity of each material according to the reference production rate of each material.

Optionally, the determining a faulty unit according to the current actual production amount of each material and the current predicted production amount of each material includes:

and if the difference value between the current actual production capacity of a certain material and the current predicted production capacity of the material is larger than a second threshold value, judging that the production unit of the material is in fault, and determining the production unit of the material as a fault unit.

Optionally, the production scheduling period is determined by:

obtaining upstream buffer stock ST of faulty unit _up And downstream buffer stock ST _down ；

Establishing a production scheduling period calculation model so as to obtain a production scheduling period T calculated by the production scheduling period calculation model _G Satisfies the following conditions:

in the production scheduling period T _G Consumable material ST of internal, fault unit _nP (T _G ) Not greater than the predicted production material ST of the upstream unit _P (T _G ) And the stock ST of the materials in the upstream buffer zone _up Sum, and, production material ST of faulty unit _nD (T _G ) With downstream buffer material inventory ST _down The sum of which is not less than the predicted consumed material ST of the downstream unit _D (T _G )。

Optionally, the step of determining the production scheduling period further includes:

calculating the production scheduling period T obtained by the production scheduling period calculation model _G And a preset production scheduling period threshold value T _max By comparison, if T _G Greater than T _max Then determine T _max For the final production scheduling period, if T _G Less than T _max Determining T _G Scheduling the cycle for the final production.

In a second aspect of the present invention, a hybrid scheduling method under a fault uncertainty condition is provided, including:

acquiring the current actual production quantity of each material in real time;

acquiring the current predicted production of each material, and determining a fault unit according to the current actual production of each material and the current predicted production of each material;

determining the execution of the scheduling by comparing the number of faulty units with a first threshold:

when the number of the fault units is larger than a first threshold value, performing rescheduling;

when the number of the fault units is smaller than the first threshold value, judging whether the predicted execution time of the modified scheduling is larger than or equal to the production scheduling period: if yes, executing the rescheduling; otherwise, executing the modified scheduling.

Optionally, the method further comprises:

a base production rate for each material is generated and a predicted production volume for each material is calculated based on the base production rate for each material.

Optionally, the method for determining the production scheduling period includes:

obtaining upstream buffer stock ST of faulty unit _up And the material stock ST of the downstream buffer area _down ；

in a production scheduling period T _G Consumption materials ST of internal, fault units _nP (T _G ) Not greater than the upstream unit's expected production material ST _P (T _G ) And the stock of materials in the upstream buffer area ST _up Sum, and, production material ST of faulty unit _nD (T _G ) With downstream buffer material inventory ST _down The sum of which is not less than the predicted consumed material ST of the downstream unit _D (T _G )。

calculating the production scheduling period T obtained by the production scheduling period calculation model _G And presetProduction scheduling period threshold T _max By comparison, if T _G Greater than T _max Determining T _max For the final production scheduling period, if T _G Less than T _max Then determine T _G Scheduling the cycle for the final production.

The technical scheme of the invention judges whether the production is delayed or the fault unit is determined in advance by monitoring the actual production quantity of the material in real time, selects the modified scheduling or the rescheduling according to whether the quantity of the fault units reaches the set threshold value and the comparison judgment of the predicted execution time of the modified scheduling and the production scheduling period, adopts the modified scheduling when the fault range is smaller, adopts the rescheduling when the fault range is larger or the predicted execution time of the modified scheduling is larger than the time of the production scheduling period, organically combines the modified scheduling and the rescheduling, and has the advantages of good uncertainty resistance effect, low calculation capability requirement and certain stability.

Additional features and advantages of embodiments of the invention will be set forth in the detailed description which follows.

Drawings

The accompanying drawings, which are included to provide a further understanding of the embodiments of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the embodiments of the invention without limiting the embodiments of the invention. In the drawings:

FIG. 1 is a schematic block diagram of a system of a hybrid scheduling system under uncertain fault conditions according to an embodiment of the present invention;

fig. 2 is a schematic diagram of a scheduling flow of a hybrid scheduling system under a fault uncertainty condition according to an embodiment of the present invention;

fig. 3 is a flowchart of a scheduling method of a hybrid scheduling system under a fault uncertainty condition according to an embodiment of the present invention.

Detailed Description

The following detailed description of embodiments of the invention refers to the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.

In the embodiments of the present invention, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising a … …" does not exclude the presence of another identical element in a process, method, article, or apparatus that comprises the element.

As shown in fig. 1, fig. 2 and fig. 3, in a first aspect of the present invention, a hybrid scheduling system under uncertain fault conditions is provided, including a coordination control module, a modified scheduling module and a rescheduling module, where the coordination control module includes:

the inventory monitoring unit is configured to acquire the current actual production quantity of each material in real time;

the rule selection unit is configured to call the rescheduling module when the number of the fault units is larger than a first threshold value; when the number of the fault units is smaller than a first threshold value, judging whether the predicted execution time of the modified scheduling is larger than or equal to the production scheduling period: if so, calling a rescheduling module, otherwise, calling a correction type scheduling module;

the modified scheduling module is used for executing modified scheduling when being called and predicting the execution time; the rescheduling module is used for executing rescheduling when being called.

Therefore, the embodiment monitors the actual production quantity of the materials in real time through the coordination control module to judge whether the production is delayed or whether the fault units are determined in advance, whether the quantity of the fault units reaches the set threshold value or not is judged, and the comparison between the predicted execution time of the modified scheduling and the production scheduling period judges whether the modified scheduling or the rescheduling is selected, when the fault range is small, the modified scheduling is adopted, when the fault range is large, or the predicted execution time of the modified scheduling is larger than the time of the production scheduling period, the rescheduling is adopted, the modified scheduling and the rescheduling are organically combined, and the method has the advantages of being good in uncertainty resisting effect, low in computing capacity requirement and having certain stability.

Specifically, a Manufacturing Execution System (MES) based on real-time production data acquisition and analysis provides a real-time information environment for workshop scheduling, which is a core module of the MES System and directly relates to peculiar production, operation and management efficiency. The scheduling system provided by the embodiment comprises a coordination control module, a modified scheduling module and a rescheduling module, wherein a flow industrial scheduling model is established based on STN (state task network), and the scheduling model can solve the MILP (hybrid linear programming) problem through a solver CPLEX to obtain a result quickly and effectively, wherein the modified scheduling module is used for executing a modified scheduling strategy prestored in a strategy library when being called, and the modified scheduling strategy is used for adjusting the material benchmark production rate of a fault unit so as to balance the material production of the fault unit within the predicted execution time of the modified scheduling; the rescheduling module is used for executing a rescheduling strategy stored in a strategy library in advance when being called, and rescheduling comprises the step of generating a new production rate of each material as a reference production rate so as to enable the production of all the materials to reach balance. The modified scheduling strategy can repair the original scheduling strategy according to the change of the system state in the execution of the scheduling scheme, and a feasible scheme is quickly found by using a local search algorithm with a heuristic function, so that the performance of the scheduling scheme is not greatly different from that of the original scheduling scheme. The rescheduling strategy requires that the scheduling scheme be recompiled after a disturbance occurs in the production process. The rescheduling target comprises the minimum adjustment amount of a scheduling scheme or the maximum production efficiency and the like. Rescheduling can avoid modified scheduling from not considering the characteristics of global optimization. Currently common rescheduling schemes include: right shift rescheduling: shifting the part which is not started in the original scheduling scheme to the right along a time axis so as to deal with the emergency; heuristic rescheduling: applying heuristic rules to generate a new feasible scheduling scheme; and (3) complete rescheduling: and re-distributing the tasks which are not started. The right-shift rescheduling method is small in application range and only suitable for the situation with small influence of unexpected interference, such as short-time fault of a machine, and if the machine fault is serious and the downtime is unpredictable, the right-shift rescheduling method cannot be applied. What heuristic rules approach obtains is usually a feasible solution, not an optimized solution: the full rescheduling method can avoid the disadvantages of the above methods, but has a certain reaction time. The modified scheduling strategy and the rescheduling strategy can be determined according to the actual production scheduling requirement, and the specific algorithm of the modified scheduling and the rescheduling belongs to the prior art and is not described herein again. In the embodiment, the inventory monitoring unit acquires the current actual production amount of each material in the production process in real time through the MES, namely the actual production amount of each production unit, and sends the acquired data to the inventory analysis unit, the inventory analysis unit acquires the current predicted production amount of each material, judges whether the production unit of each material fails or not by comparing whether the difference value between the current actual production amount of each material and the current predicted production amount is within a reasonable range or not, and determines the equipment as a failure unit if the equipment fails. After the inventory analysis unit judges that the fault units exist, the rule selection unit judges whether the number of the current fault units is larger than or equal to a preset first threshold value or not, if so, the current disturbance is considered to be large, and the scheduling requirement cannot be met through repair, and the rule selection unit calls a rescheduling module to perform complete rescheduling on the current production task; if the number of the current fault units is smaller than a preset first threshold and is larger than or equal to 1, a rule selection unit judges whether the predicted execution time of the modified scheduling is larger than a production scheduling period, wherein the predicted execution time refers to the minimum time required for completing the modified scheduling, namely the fault units are overproduced, the production rate is reduced, the production is insufficient, the production rate is increased, so that the time required by production stability is ensured, the time can be obtained through a modified scheduling strategy, the production scheduling period refers to the period that the modified scheduling performed in the production scheduling period does not influence the upstream and downstream production, if the predicted execution time of the modified scheduling is larger than the production scheduling period, the modified scheduling is considered to be incapable of ensuring that the production can reach the scheduling requirement through repair in the production scheduling period which does not influence the upstream and downstream production, a rescheduling module is called, and if the predicted execution time of the modified scheduling is smaller than the production scheduling period, the modified scheduling module is considered to be capable of ensuring that the production can reach the scheduling requirement through repair in the production scheduling period which does not influence the upstream and downstream production, and the modified scheduling module is called.

The coordination control module comprises an inventory monitoring unit, an inventory analysis unit and a rule selection unit, wherein the inventory monitoring unit is used for monitoring the inventory of core materials to obtain the inventory of a monitored material set SS, and the inventory st of the actually monitored materials is _ss Monitoring material stock st with reference _norm,ss Comparing to obtain the material difference dif between the actual production and the predicted production of the monitored material set _ss So as to analyze the fluctuation state of the material according to the obtained material difference, when the fluctuation is abnormal, namely the production monitoring alarm parameter e is more than 0, a rescheduling strategy is started, and z is used ₁ Indicating the status of the rescheduling strategy if z ₁ =1, then represent that the re-scheduling strategy is started, production monitoring is required in each production time unit, and the monitoring result is expressed as dif _ss ＝st _ss -st _normss

Production monitoring alarm parameters are denoted as e _ss ＝abs(dif _ss )-θst _normss

Wherein theta is a fluctuation alarm threshold value, and the state of the rescheduling strategy is expressed as

Meanwhile, the hysteresis quantity d of each production unit and the number d of abnormal production units can be obtained by observing characteristic materials and material relations among the production units _a ：d _j ＝N(dif _ss )

Wherein N is a speculative model.

The rule selection unit is used for controlling the conversion between the modified scheduling module and the rescheduling module, and the modified scheduling module has small instruction adjustment range, low cost and high speed, so that the production rate v is adjusted to be within a small range under the condition of abnormal production _j Adjusting, namely calling a rescheduling module to update the production reference ST to ensure that production is finished when the fluctuation is not suppressed after a period of local instruction adjustment _norm And V _norm . The selection rule of the embodiment selects whether to call the modified scheduling module or the rescheduling module according to the scheduling time period and the production fluctuation range. Scheduling time t when modified scheduling _p Less than the scheduling period T, i.e. when T _p <When T is reached, a correction type scheduling module is called; scheduling time t when modified scheduling _p Not less than the scheduling period T, i.e. when T _p And when the T is more than or equal to T, calling a rescheduling module. If the number of production abnormal units is too large (d) _a And if the value is larger than the set upper limit a), calling a rescheduling module. By z ₂ Indicates the selection status of the scheduling policy if z ₂ If =1, the rescheduling module is selected; if z is ₂ =0, the scheduling policy selected is modified scheduling, scheduling modified scheduling module, and the scheduling policy status is expressed as

In the embodiment, the system further comprises a strategy library F, a rule library R and a database D, wherein the strategy library refers to a common scheduling strategy adopted by the production scheduling plan and integrates a modified scheduling strategy and a rescheduling scheduling strategy; the rule base is a rule adopted in the process of forming the production scheduling plan and comprises an actual production connection and constraint rule, the database comprises a management module base of the database, and the database comprises three types of data which are respectively plan type data, scheduling process type data and scheduling result type data of the unit production plan. F = { F ₁ ,F ₂ …F _M ,f ₁ ,f ₂ …f _N In which F ₁ ,F ₂ …F _M For rescheduling strategy, f ₁ ,f ₂ …f _N For a modified scheduling policy, R = { R ₁ ,R ₂ …R _N }，D＝{ST _norm ,V _norm ；V _m ,ST _m ,V _nj ；t _p T }, wherein ST _norm ,V _norm Rescheduling update rate matrix and inventory matrix V for planning class data _m ,ST _m And a modified scheduling rate adjustment matrix V _nj All belong to scheduling process class data, scheduling time of modified scheduling and corresponding period t _p And T is scheduling result class data.

When the modified scheduling module is called, the modified scheduling module calculates and obtains a production rate adjustment matrix V in a scheduling time period by calling a strategy library F _nj Correcting the current production rate, V _nj ＝f _n (Dif,T,R ₁ ,R ₂ …R _N ) Dif is a set of differences of materials, v _j ＝v _normj +z ₁ (1-z ₂ )v _nj +ξ

And the rescheduling module is used for calculating and optimizing the current production condition of the whole factory and updating the production standard. When a rescheduling module is called, after current stock ST of all materials is obtained, a residual order is obtained after the comparison with the initial order, a proper rescheduling strategy is called from a strategy library F, current stock ST of all materials, residual order Dem' and a constraint rule are input, and a new reference stock matrix ST is obtained through calculation _m And a reference rate matrix V _m ：(V _m ,ST _m )＝F _m (ST,Dem',R ₁ ,R ₂ …R _N ) If z is ₁ ^ts =1 and z ₂ ^ts =1 or z ₁ ^ts z ₂ ^ts If =1, updating the reference production material and the reference production rate: ST (ST) _norm ^ts ＝z ₁ ^ts z ₂ ^ts ST _m ^ts +(1-z ₁ ^ts z ₂ ^ts )ST _norm ^ts-1 ，V _norm ^ts ＝z ₁ ^ts z ₂ ^ts V _m ^ts +(1-z ₁ ^ts z ₂ ^ts )V _norm ^ts-1 。

Meanwhile, in order to cope with an emergency, a temporary scheduling policy can be embedded in the rescheduling module, when algorithm optimization calculation is carried out, if no solution exists, the capacity of equipment and the stock of materials need to be adjusted, and the solution can be written into a rule base in advance, so that R = { R = (R) } can be written into a rule base ₁ ,R ₂ …R _N ,R _em In which R is _em And adjusting rules of the temporary scheduling strategy.

In the actual production process, because of the influence of uncertain conditions, there is a certain error in the actual production quantity and the predicted production quantity of each material, if the error is too large, the production will be influenced, therefore, the fault unit is determined according to the current actual production quantity of each material and the current predicted production quantity of each material, and the fault unit comprises:

and if the difference value between the current actual production capacity of a certain material and the current predicted production capacity of the material is larger than a second threshold value, judging that the production unit of the material is in fault, and determining the production unit of the material as a fault unit. When the error between the actual production quantity and the predicted production quantity of each material is larger than the acceptable range of the production system, the production unit is considered to be in fault, and whether a correction type scheduling module or a rescheduling module is called to eliminate the influence of the fault unit on the production system needs to be further judged.

In this embodiment, the basic scheduling business process is to perform real-time data collection and analysis on uncertain factors, i.e., dynamic disturbances, in production through the MES environment on the basis of static scheduling, and adopt a dynamic scheduling policy to solve the scheduling problem, so the system further includes:

and the static scheduling module is used for generating the reference production rate of each material and calculating the predicted production of each material according to the reference production rate of each material. The static scheduling module comprises a scheduling calculation unit and a result analysis unit, the scheduling calculation unit is used for carrying out modeling optimization calculation on a production order input by an MES (manufacturing execution system), so that a scheduling scheme corresponding to the completed production order is obtained, the obtained scheduling scheme comprises an initial production rate matrix and a material inventory matrix of each material with a mapping relation, the initial production rate matrix and the material inventory matrix are set as production references, namely a reference rate matrix and a reference material inventory matrix, the reference rate matrix is used as an initial instruction set for equipment production in the production process, the reference material inventory matrix is input into the inventory monitoring module as a scheduling reference, rows and columns of the reference rate matrix are respectively equipment numbers and time, rows and columns of the reference material inventory matrix are respectively material names and time, and the reference rate matrix and the reference material inventory matrix are used for describing changes of the production rate and the material production capacity of each equipment in the production process. And the result analysis unit is used for calculating the predicted production capacity of each material at the current moment according to the reference speed matrix and the reference material inventory matrix. Specifically, according to the production relation and material resources, a production model M taking a production order Dem as input is established, the target function is the lowest total cost, and therefore the optimal production scheduling scheme is obtained through calculation. Wherein the total cost comprises: material cost, running cost, and penalty cost. The operating costs are divided into fixed operating costs, which are the fixed overhead of the plant in the operating state, and variable costs related to the production rate.

The objective function of this embodiment is as follows:

wherein s is material, j is equipment unit, ts is production time, price is raw material, ST _P Fixcost is the amount of material consumed _j Is a fixed cost unit price of unit j, varcost _j Is a variable cost unit price of unit j, u _s For the penalty cost unit price, U, of incomplete material s _s Is the short-cut amount of the material s,

for the production state of unit j at time ts,

for the throughput of unit j at time ts,

then, an initial model and results are obtained according to the above method: rt = M (Dem), where M is the production model and Rt is the scheduling calculation result.

The result analysis unit is used for analyzing the result of the optimization calculation to obtain the production instruction of the minimum time granularity and the material inventory change, and the analysis result is represented by two parameters: production rate matrix V ₀ And a production materials matrix ST representing the inventory of materials ₀ . In the workshop production process, the obtained decomposition scheduling scheme is used as the standard working condition of equipment production, namely an initial production rate matrix V ₀ And producing a material matrix ST ₀ As a reference rate matrix V _norm And a reference material inventory matrix ST _norm I.e. stock of reference materials ST _norm ＝ST ₀ Base production rate V _norm ＝V ₀ The initial production rate executes the production command according to the reference production rate, but because of the fault uncertainty, there is a disturbance xi in the actual production process, then the actual production speed v _j ＝v _normj +ξ

The modified scheduling policy may be determined according to actual production, and may repair production scheduling under the condition that the production has small disturbance, so as to stabilize the production, but if the local repair time is too long, the production of other units may be affected, and the entire production system is affected, and therefore, a production scheduling period needs to be determined to determine whether to invoke the modified scheduling module or the rescheduling module, so as to ensure the stability of the production system, in this embodiment, the production scheduling period is determined through the following steps:

in the production scheduling period T _G Consumption materials ST of internal, fault units _nP (T _G ) Not greater than the predicted production material ST of the upstream unit _P (T _G ) And the stock ST of the materials in the upstream buffer zone _up Sum, and, production material ST of faulty unit _nD (T _G ) With downstream buffer material inventory ST _down The sum of which is not less than the predicted consumed material ST of the downstream unit _D (T _G ) I.e. production scheduling period T _G It can be calculated as follows:

ST _nP (T)≤ST _P (T)+ST _up ；

ST _nD (T)+ST _down ≥ST _D (T)；

T _G ＝G(ST _norm ,V _norm ,ST _up ,ST _down ) Where G is a periodic calculation model, ST _norm For a base material inventory matrix, V _norm When calculating the production scheduling period, taking the upstream unit material and the downstream unit material as constraint conditions, and gradually increasing from small to large, such as:

setting the initial production scheduling period as 1, obtaining the scheduling speed of the fault unit according to the modified scheduling strategy, and judging whether the production scheduling period meets the following requirements:

ST _nP (T)≤ST _P (T)+ST _up ；

ST _nD (T)+ST _down ≥ST _D (T)；

and if the production scheduling period is not satisfied, ending the calculation, and taking the result obtained in the previous time as the production scheduling period.

Since the modified scheduling for a long time may affect the production of some devices in the actual production process, the method for determining the production scheduling period further includes:

will pass the production scheduling period calculation moduleProduction scheduling period T obtained by type calculation _G And a preset production scheduling period threshold value T _max By comparison, if T _G Greater than T _max Then determine T _max For the final production scheduling period, if T _G Less than T _max Determining T _G For the final production scheduling period, the production scheduling period threshold T _max Determining according to actual production situation, representing upper limit of time period, and determining threshold value T of production scheduling period _max The influence that long-time correction formula dispatch probably caused to production system can effectually be avoided, the stability of production system has effectually been guaranteed.

The scheduling control process of the present embodiment is as follows:

firstly, a standard working condition is obtained through a static scheduling module, and an initial production rate matrix V is obtained after Dem modeling optimization calculation is carried out on an input order according to a production relation and material resources ₀ And material inventory matrix ST ₀ And set it as a production benchmark, i.e., the benchmark rate matrix V _norm And a reference material inventory matrix ST _norm . In the production process, V is added _norm As an initial instruction set for the production of the device, ST _norm And the data is input into a production monitoring module as a scheduling reference.

In the production process, due to the existence of fault uncertainty, the fault cannot be completely executed according to the instruction of the standard working condition, so the actual production material inventory is different from the standard working condition. In each time unit, the inventory monitoring unit monitors the inventory state of a specific material set SS and compares the actual monitored material inventory st _ss And the expected material inventory st _norm,ss To obtain a material difference dif of the monitored material set _ss And then analyzing and judging whether a fault occurs or not, and positioning the fault unit according to the production relation to obtain the fault unit and the corresponding delay production.

If the fault occurs, the scheduling control module is required to be called to ensure that the production is finished. In the embodiment, the rule selection unit is used for controlling the selection of the modified scheduling module and the rescheduling module, the fault range is judged firstly, and if the number of the fault units is excessive, namely the number d of the fault units _a Greater than or equal toCalling a rescheduling module at a set upper limit a; secondly, judging the time period of production scheduling, and when the predicted execution time t of the modified scheduling _p Less than the production scheduling period T _G When, i.e. when t _p <T _G Then, calling a correction type scheduling module; predicted execution time t when modified scheduling _p Greater than or equal to the production scheduling period T _G When, i.e. when t _p ≥T _G Then, the rescheduling module is called, and the initial value is set as t _p <T。

After receiving the instruction, the modified scheduling module acquires a material stock ST of a downstream buffer area of the fault unit _down And upstream buffer stock ST _up Calling the predicted production rate of upstream and downstream production units, synthesizing the production relation to obtain the minimum scheduling time without influencing the production of other units, calling a modified scheduling strategy in a strategy library, and obtaining a production rate adjustment matrix V through the modified scheduling strategy _nj The production rate matrix is modified to adjust the production rate of the faulty unit to resist the uncertainty.

After receiving the instruction, the rescheduling module collects the inventory data of all the current materials, compares the inventory data with the initial order to obtain the quantity of the to-be-generated materials of the current remaining order, calls a rescheduling strategy in the strategy library, and calculates a new production rate matrix V through the rescheduling strategy according to the inventory of the current materials, the remaining order and the constraint rule _m And material inventory matrix ST _m Instead of updating the reference rate matrix V _norm And a reference material inventory matrix ST _norm 。

And (5) circulating the process until the production is finished.

In conclusion, the scheduling system of the embodiment has good robustness, and can solve local faults with low influence, high speed and high efficiency; the method has a good coping effect on the complex range fault, and can ensure that order production is completed as far as possible. The scheduling strategy of the scheduling system is set up by the strategy base, the scheduling rule is defined by the rule base, the scheduling control precision is controlled by variables such as a fluctuation threshold value and a modified scheduling period, the universality of the scheduling model is effectively improved, meanwhile, the scheduling system improved by the embodiment has low requirements on computing resources and facility reaction speed, and the scheduling cost is low.

acquiring the current actual production quantity of each material in real time;

when the number of the fault units is smaller than a first threshold value, judging whether the predicted execution time of the modified scheduling is larger than or equal to the production scheduling period: if yes, executing rescheduling; otherwise, modified scheduling is performed.

Optionally, the method further comprises:

Optionally, determining the faulty unit according to the current actual production capacity of each material and the current predicted production capacity of each material, includes:

in the production scheduling period T _G Consumable material ST of internal, fault unit _nP (T _G ) Not greater than the upstream unit's expected production material ST _P (T _G ) And the stock of materials in the upstream buffer area ST _up Sum, and, production material ST of faulty unit _nD (T _G ) With downstream buffer material inventory ST _down The sum of which is not less than the predicted consumed material ST of the downstream unit _D (T _G )。

calculating the production scheduling period T obtained by the production scheduling period calculation model _G And a preset production scheduling period threshold value T _max By comparison, if T _G Greater than T _max Determining T _max For the final production scheduling period, if T _G Less than T _max Then determine T _G Scheduling the cycle for the final production.

The following is illustrated by a specific simulation example:

a certain production workshop comprises nine units, namely an ethylene cracking unit, a waste alkali oxidation unit, an aromatic hydrocarbon extraction unit, a butadiene extraction unit, a gasoline hydrogenation unit, a synthetic ammonia unit, an OCU unit, a polypropylene unit and a polyethylene unit, and the scheduling control problem of the unit is ignored because the waste alkali oxidation unit is a wastewater treatment unit and has no coupling relation with other units and does not influence the production of products. The specific production yield relationship is obtained by converting the production design index, and is shown in tables 1 and 2 after simplified arrangement. The product produced comprises: the fuel oil, the mixed benzene, the butadiene, the hydrogenated carbon nine, the liquid ammonia, the polyethylene and the polypropylene are converted according to the annual output of the products in the workshop, the production order of one week in the workshop is taken as a production target, and as shown in table 3, the simulated minimum time granularity is taken to be half an hour.

TABLE 1

TABLE 2

Product name	Fuel oil	Mixed benzene	Butadiene	Hydrogenated carbon nine	Liquid ammonia	Polyethylene	Polypropylene
								Order form (ton)	408	1344	1333	136.5	3150	9030	12180

TABLE 3

According to the above, four modules of the scheduling control system are built in sequence: the system comprises a static scheduling module, a coordination control module, a correction type scheduling module and a rescheduling module.

A static scheduling module:

an STN modeling method is adopted, a mathematical model is established according to production relation and materials, production scheduling problems are converted into typical MIP problems, a CPLEX built-in solver is adopted to carry out optimization calculation on a GAMS platform, and the minimum total cost objective function is as follows:

the constraints of the model are summarized as follows:

the variables involved in the model are summarized as follows:

t is a planning period;

inventory of material s at the end of planning period t;

production target of material s in a planned cycle t;

the delivery quantity of the material s in the planning period t;

incomplete amount of material s at the end of the planning period t;

production demand of material s in a planned cycle t;

u _s punishment cost unit price of incomplete material s;

i, production tasks;

I _j production tasks that can be produced in production unit j;

I _s production tasks related to the material s;

j, a production unit;

J _i a production unit capable of completing the production task i;

n is the event point within the time period;

s, collecting all materials;

S _P producing a target material set;

unit j produces the minimum production rate for task i;

the unit j produces the maximum production rate of the task i;

respectively representing the proportion of consumption and production when the production task i is finished;

α _ij unit j produces a fixed value in the production time of task i;

β _ij unit j produces a variable value in the production time of task i;

h, time period;

wv _i,j,n the flag unit j produces a binary variable of the task i at the event point n;

st _s,n inventory of material s at event point n;

maximum stock value of material s;

initial value of material s in time period t;

b _i,j,n unit j produces the material throughput for task i at event point n;

Ts _i,j,n unit j produces the start time of task i at event point n;

Tf _i,j,n unit j produces the end time of task i at event point n.

The optimized calculation on GAMS can obtain the production rate of each unit corresponding to the order and the start time and the end time of the production in each stage: (B, ts, tf) = M (Dem), and then analyzing the obtained data instruction file by python to obtain each half-smallSpecific production rate matrix and material inventory matrix (V) of time ₀ ,ST ₀ ) Set it as production basis, i.e. the standard rate matrix V _norm And a standard material inventory matrix ST _norm In the workshop production process, V _norm As an initial instruction set for equipment production, ST _norm And the data is input into a production monitoring module as a scheduling control reference.

A coordination control module:

monitoring the stock of core materials such as fuel oil, mixed benzene, butadiene, hydrogenated carbon nine, liquid ammonia, polyethylene and polypropylene at each time granularity, and comparing the stock with the yield of dispatching standard materials to obtain a material difference dif _ss Then, calculating production monitoring alarm parameters, wherein the threshold value is 0.5 per mill:

e _ss ＝abs(dif _ss )-0.0005st _norm,ss

to material difference dif _ss Further analysis shows that the production states of the units one, three, four, five, seven, eight and nine respectively correspond to the stock states of the materials of fuel oil, mixed benzene, butadiene, hydrogenated carbon nine, liquid ammonia, polyethylene and polypropylene one by one, so that the production states of the seven units can be expressed by the stock states of the seven materials, the production state of the unit six can be calculated by the production states of the unit one and the unit eight and the stock of the material of butylene, and finally, the material difference value and the number of fault units of all fault units can be obtained.

Database D = { ST = _norm ,V _norm ；V _m ,ST _m ,V _n ；t _p T, policy base F = { F }, policy base F = ₁ ,f ₁ },F ₁ Is a rescheduling strategy, calling a CPLEX solver to solve, f ₁ Is a modified scheduling strategy, the materials of which the units lag due to uncertainty are cumulatively supplemented in a scheduling period, and a rule base R = { R = ₁ }，R ₁ The modified scheduling period is less than 30.

The rule selection unit controls the modified scheduling module and the rescheduling moduleAnd (4) switching between. Scheduling time t when modified scheduling _p When the scheduling period is less than the scheduling period T, calling a modified scheduling module; when scheduling time t of modified scheduling _p And when the scheduling period is not less than the scheduling period T, calling a rescheduling module. And if the number of the abnormal production units is excessive, calling a rescheduling module. Since the number of cells is small, the upper limit a =1 is taken here, i.e. if the number of faulty cells d _a If the number is more than 1, the rescheduling module is directly called.

The modified scheduling module:

after receiving the instruction, the modified scheduling module acquires a material stock ST of a downstream buffer zone of the fault unit _down And upstream buffer inventory ST _up Obtaining an upstream predicted production material ST in the scheduling period T according to the predicted production rate of the upper unit _P (T) obtaining a predicted consumed material ST downstream in the period T from the predicted production rate of the lower layer unit _D (T) obtaining a scheduled time period T without affecting the production of other units through the production relation _G . Finally it is related to the upper limit T of the time period _max And taking a smaller value as a modified scheduling period after comparison:

T＝min(G(ST _norm ,V _norm ,ST _up ,ST _down ),T _max ) Invoking modified scheduling policy f ₁ Calculating to obtain a production rate adjustment matrix in a scheduling time period: v _1i ＝f ₁ (Dif,T,R ₁ ) And correcting the production rate: v. of _j ＝v _normj +z ₁ (1-z ₂ )v _nj +ξ

A rescheduling module:

after receiving the instruction, the rescheduling module acquires the current material, converts the current material to obtain the current residual order, and calls a strategy F ₁ Calculating to obtain a new scheduling standard material matrix and a standard rate matrix: (V) ₁ ,ST ₁ )＝F ₁ (ST, dem') if z ₁ ^ts =1 and z ₂ ^ts =1 or z ₁ ^ts z ₂ ^ts When =1, for standard productsMaterial and standard production rates were updated:

ST _norm ^ts ＝z ₁ ^ts z ₂ ^ts ST ₁ ^ts +(1-z ₁ ^ts z ₂ ^ts )ST _norm ^ts-1 ；

V _norm ^ts ＝z ₁ ^ts z ₂ ^ts V ₁ ^ts +(1-z ₁ ^ts z ₂ ^ts )V _norm ^ts-1 ；

in order to compare the scheduling effect, the simulation establishes a modified scheduling strategy and an event-driven rolling rescheduling strategy. The scheduling method of the modified scheduling strategy in the production process is that after static scheduling is adopted, after the uncertain disturbance causes production abnormity, the subsequent production instructions of each fault unit are adjusted quantitatively. The scheduling method of the event-driven rolling rescheduling strategy in the production process is to perform rescheduling after static scheduling when a fault is monitored, so as to overcome uncertain interference.

In simulation, three disturbance scenes are designed by combining production practice, comprehensively considering three important factors of local faults and range faults, slight faults and serious faults and upstream and downstream equipment: the method comprises the following steps of local fault, range fault and combination of the local fault and the range fault, wherein the correspondence is as follows:

A. a plurality of local faults in short time respectively apply interference to the first unit, the fourth unit and the eighth unit in different time periods, so that the production capacity of the units is reduced to one tenth;

B. long-time range failure, namely simultaneously applying interference to a plurality of units, namely one, five or nine units in a certain time period, so that the production capacity of the units is reduced to one tenth;

C. the method has the advantages that the local fault in a short time and the serious fault in a long time range are caused, the interference is firstly exerted on one unit, and then the interference is exerted on a plurality of units, namely one, five and nine units, so that the production capacity is reduced to one tenth.

The cost statistics is divided into material cost, operation cost and punishment cost, and the specific settings are shown in tables 4 and 5:

material(s)	TK_Naphtha	TK_LPG1	TK_LPG2	TK_LPG3	Gas_H_CTL	Gas_N
							Monovalent (yuan/ton)	2770	2600	2600	2600	800	34

TABLE 4

TABLE 5

The simulation cost result is as follows (unit: ten thousand yuan):

normal production cost:

8668.95+863.12+0＝9532.07；

modified scheduling policy cost:

(8670.87+8670.96+8671.75)/3+(866.04+870.11+870.90)/3+(0+2.8+2.7)/3＝9542.04；

event-driven-based rolling rescheduling policy cost:

(8669.01+8670.95+8670.98)/3+(869.21+866.40+868.66)/3+(0+0+0)/3＝9538.40；

hybrid scheduling policy cost:

(8670.97+8670.95+8670.97)/3+(868.19+866.82+868.42)/3+(0+0+0)/3＝9538.77。

according to simulation results, materials produced by the three strategies are basically consistent, so consumed raw materials are basically consistent, the operation cost and the total cost of the hybrid scheduling strategy adopting the embodiment are basically equal to those of the rolling rescheduling strategy, but the calculation resource requirement of the embodiment is lower than that of the rolling rescheduling strategy, and in addition, for scenes B and C, the modified scheduling strategy cannot completely complete orders, and a part of punishment cost can be generated.

To further analyze the cost loss, taking the core unit as an example to perform the production rate analysis, it can be obtained through simulation that in the scenario C, since the production materials of a certain production unit are consistent, the variable cost of the modified scheduling and the normal production is the same, but the running time of the equipment in the modified scheduling production is longer, and therefore, the fixed cost thereof is increased, which is the source of the excess cost of the scheduling.

In summary, the total cost of the modified scheduling policy is the highest, and the order is not completed; the mixed scheduling strategy and the event-driven rolling rescheduling have the same cost basically, and can complete orders, but the rolling rescheduling has more complete rescheduling times, so that the stability of the system is reduced to a certain extent, and in addition, the mixed scheduling strategy consumes less computing resources. Therefore, the hybrid scheduling strategy combines the advantages of the modified scheduling and the event-driven rolling rescheduling, and has good scheduling effect and less consumed computing resources.

The scheduling strategy of the embodiment is built by a strategy base, the scheduling rule is defined by the rule base, the scheduling control precision is controlled by variables such as a fluctuation threshold value, a modified scheduling period and the like, so that the universality of a scheduling model is greatly improved, and various actual scenes can be dealt with only by partially adjusting the definition parameters of the scheduling model; the optimization calculation is carried out through static scheduling, the production cost is controlled, real-time feedback can be achieved aiming at the production uncertainty through small-range instruction adjustment, the fault influence is reduced, the rescheduling strategy ensures stable operation, the order completion is ensured, and a three-in-one low-cost and quick-response scheduling model is formed.

The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

While the embodiments of the present invention have been described in detail with reference to the accompanying drawings, the embodiments of the present invention are not limited to the details of the above embodiments, and various simple modifications can be made to the technical solution of the embodiments of the present invention within the technical idea of the embodiments of the present invention, and the simple modifications are within the scope of the embodiments of the present invention.

It should be noted that the various features described in the above embodiments may be combined in any suitable manner without departing from the scope of the invention. In order to avoid unnecessary repetition, the embodiments of the present invention will not be described separately for the various possible combinations.

Those skilled in the art will appreciate that all or part of the steps in the method for implementing the above embodiments may be implemented by a program, which is stored in a storage medium and includes several instructions to enable a single chip, a chip, or a processor (processor) to execute all or part of the steps in the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.

Claims

1. A hybrid dispatch system under uncertain fault conditions, the system comprising: the system comprises a coordination control module, a correction type scheduling module and a rescheduling module;

the coordination control module comprises:

the rule selection unit is configured to call the rescheduling module when the number of the fault units is larger than or equal to a first threshold value; when the number of the fault units is smaller than the first threshold value, judging whether the predicted execution time of the modified scheduling is larger than or equal to the production scheduling period: if so, calling the rescheduling module; otherwise, calling the modified scheduling module;

the modified scheduling module is used for executing a modified scheduling strategy pre-stored in a strategy library when being called, and the modified scheduling strategy is used for adjusting the material benchmark production rate of the fault unit so as to enable the material production of the fault unit to reach balance within the predicted execution time of the modified scheduling;

the rescheduling module is used for executing a rescheduling strategy stored in a strategy library in advance when being called, wherein the rescheduling strategy comprises the step of generating a new production rate of each material as a reference production rate so as to enable the production of all the materials to reach balance.

2. The system of claim 1, further comprising:

3. The system of claim 1, wherein the determining the faulty unit according to the current actual production capacity of each material and the current predicted production capacity of each material comprises:

4. The system of claim 1, wherein the production scheduling period is determined by:

acquiring faultsUpstream buffer stock ST of unit _up And the material stock ST of the downstream buffer area _down ；

in the production scheduling period T _G Consumption materials ST of internal, fault units _nP (T _G ) Not greater than the upstream unit's expected production material ST _P (T _G ) And the stock of materials in the upstream buffer area ST _up Summing; and, production material ST of faulty unit _nD (T _G ) With downstream buffer material inventory ST _down The sum of which is not less than the predicted consumed material ST of the downstream unit _D (T _G )。

5. The system of claim 4, wherein the step of determining the production scheduling period further comprises:

calculating the production scheduling period T obtained by the production scheduling period calculation model _G And a preset production scheduling period threshold value T _max By comparison, if T _G Greater than T _max Then determine T _max For the final production scheduling period, if T _G Less than T _max Then determine T _G Scheduling the cycle for the final production.

6. A hybrid scheduling method under the condition of uncertain faults is characterized by comprising the following steps:

acquiring the current actual production of each material in real time;

executing a rescheduling strategy when the number of the fault units is greater than or equal to a first threshold value;

when the number of the fault units is smaller than the first threshold value, judging whether the predicted execution time of the modified scheduling strategy is larger than or equal to the production scheduling period: if yes, executing the rescheduling strategy; otherwise, executing a modified scheduling strategy;

the modified scheduling strategy is used for adjusting the material benchmark production rate of the fault unit so that the material production of the fault unit can reach balance within the predicted execution time of the modified scheduling;

the rescheduling strategy includes generating a new production rate for each material as a baseline production rate to balance production of all materials.

7. The method of claim 6, further comprising:

8. The method of claim 6, wherein the determining the faulty unit according to the current actual production capacity of each material and the current predicted production capacity of each material comprises:

and if the difference value between the current actual production capacity of a certain material and the current predicted production capacity of the material is larger than a second threshold value, judging that the production unit of the material is in failure, and determining the production unit of the material as a failure unit.

9. The method of claim 6, wherein the production scheduling period is determined by:

in a production scheduling period T _G Consumption materials ST of internal, fault units _nP (T _G ) Not greater than the upstream unit's expected production material ST _P (T _G ) And the stock of materials in the upstream buffer area ST _up Summing; and, production material ST of faulty unit _nD (T _G ) With downstream buffer material inventory ST _down The sum of which is not less than the predicted consumed material ST of the downstream unit _D (T _G )。

10. The method of claim 9, wherein the step of determining the production scheduling period further comprises: