CN109767118A

CN109767118A - A Dynamic Capacity Reservation Method for Limited Buffers in a Passenger Car Paint Shop with Reentrant Processes

Info

Publication number: CN109767118A
Application number: CN201910026384.7A
Authority: CN
Inventors: 韩忠华; 田旭天; 刘约翰; 林硕
Original assignee: Shenyang Jianzhu University
Current assignee: Shenyang Jianzhu University
Priority date: 2019-01-11
Filing date: 2019-01-11
Publication date: 2019-05-17

Abstract

一种在具有可重入工序的客车涂装车间中有限缓冲区动态容量预留方法，属于客车生产工艺技术领域。通过预测客车将折返执行可重入工序的工位上加工的客车发生变化情况，即折返执行可重入工序所对应缓冲区资源释放概率，在排产过程中为执行可重入工序的客车将折返要进入的缓冲区动态预留容量，使得将执行可重入工序的客车能够顺利折返进入到有限缓冲区中，不会滞留在其当前工位中，从而使得该工位出现阻塞的概率下降，降低因客车争夺缓冲区资源而导致严重连续阻塞现象对生产进程的影响，降低生产过程中死锁现象发生的概率，从而保证了客车涂装车间生产进程能够顺利的进行。The invention relates to a method for reserving dynamic capacity of a limited buffer zone in a bus painting workshop with re-entrant processes, belonging to the technical field of bus production technology. By predicting the change of the bus to be processed at the station where the reentrant process is performed, that is, the release probability of the buffer resources corresponding to the reentrant process, during the production scheduling process, the reentrant process for the bus will be The dynamic reserved capacity of the buffer zone to be reentrant allows the passenger car that performs the reentrant process to be smoothly reentrant into the limited buffer zone and will not stay in its current station, thereby reducing the probability of blockage at the station. , reducing the impact of the serious continuous blocking phenomenon on the production process caused by the competition for buffer resources by the passenger cars, and reducing the probability of deadlock in the production process, thus ensuring the smooth production process of the passenger car painting workshop.

Description

A kind of limited buffer dynamic appearance in there is the bus body painting workshop that can reentry process Measure method for obligating

Technical field

The present invention relates to a kind of in having the bus body painting workshop that can reentry process, and limited buffer dynamic capacity is reserved Method belongs to bus coating technology field.

Technical background

The production method of customization brings the difference of car process flow, and the bus coating period is longer, needs a large amount of Buffer area parking stall carry out the car to be processed such as temporary storage.In the actual production process, it is being made since car belongs to large volume Product can only be arranged a limited number of buffer areas in parking stall on bus coating line, lead to the offer production capacity in workshop and the need of production task Ask production capacity that cannot be well matched with, when the matching relationship of the two fluctuates, the car quantity stored in buffer area is easy Reach capacity the upper limit, car a upper procedure after processing is completed, not can enter buffer area, car can only be in current station The release of pending buffer area, this will lead to production process and choking phenomenon occurs, and then increase uncertain in production process.Work as production In the presence of when can reentry process in the process flow of task, the produce load that will lead to workshop is multiplied, and improves railway car manufacture The complexity of Workshop Production control, further increases the uncertainty of production process.During railway car manufacture, passenger car body The different colour bar patterns of upper air brushing are enterprise technology personnel in advance according to colour bar template complexity, and colour bar is resolved into a variety of face Color, it is every to be gone over " patch colour bar ", " spray painting ", a kind of color of " baking finish " process air brushing, global pattern is formed by multipass air brushing, So bus body painting workshop multipass colour bar process section is that one kind can typically reentry the production phase.There is the visitor that can reentry process In vehicle Painting Shop, the car that process can be reentried by executing has the characteristics that be reinserted into queue to be processed, if executed It is complete in a upper procedure for the buffer area when can reentry the car of process the buffer pool size for entrance of turning back being had reached the upper limit Work car can not enter the buffer area, so that there is choking phenomenon in the production link before the buffer area, meanwhile, it to hold Row can reentry the car of process because detecting without residual capacity in the buffer area to be entered, then the car, which remains in, works as In preceding station, cause station where it that can not discharge in time, so that should enter the car of the station can not carry out normally Production and processing is led so that choking phenomenon occurs in the production link after the buffer area, and then forms chain production obstruction It causes entire production process that deadlock situation occurs, seriously affects normal production process, the presence of limited buffer and process can be reentried Presence will lead to and generate higher misfortune between the car of Continuous maching and close property, if having the car quantity for reentrying process to increase Add, then can further increase the probability of deadlock situation appearance, will lead to production process under serious situation and stagnate completely, manufactured Cheng Wufa is carried out, and significantly increases the difficulty of the production management tissue of enterprise.If the car that execution can reentry process will be rolled over Returning the buffer area to be entered then can reentry process for execution for that need to execute the car advance reservation capacity that can reentry process Car will not turn back to execute because of car and can reentry the buffer area of process and reach its maximum size and be trapped in its current station, Car will turn back execute reentry process buffer area can receive the car so that the station of car processing tasks is completed There is the probability blocked decline, and then the probability of deadlock situation appearance can be reduced.

In order to solve this problem, China's patent of invention, Patent No. CN103927689A's " one kind can reentry type manufacture System batch processor dispatch control method ", disclose a kind of dispatch control method based on pull-type rule.This method is directed to because can Reentry process with it is non-reentry between process lack manufacture cooperate with the problem of studied, pass through the scheduling based on pull-type rule Control method realization can reentry process and it is non-reentry good Collaborative Manufacturing between process, reducing can reentry in type manufacture system The probability that choking phenomenon occurs.But this method is studied only for the workshop with unlimited buffer area, is not considered The limited situation in buffer area in workshop.

For occurring production blocking even deadlock situation in the production process of manufacturing shop, adjusted in academic article frequently with dynamic Whole buffer pool size or the method for adding common buffer solve, but for actual railway car manufacture workshop, bus coating line Once being completed by construction, the buffer pool size between process just is substantially fixed, while setting on car disengaging production line The common buffer set will increase the transhipment time of car, and then influence total complete time, so dynamic adjustment buffer pool size Or the method limitation by all many conditions in practical engineering applications of common buffer is added, therefore can weigh currently for having Enter the production obstruction and deadlock situation occurred during the limited bus coating of process and buffer pool size, there is no effective solution Method.

Summary of the invention

It is reserved that the present invention provides a kind of limited buffer dynamic capacity in having the bus body painting workshop that can reentry process Method is turned back and is held by predicting that the car execution that will turn back can reentry the car processed on the station of process and change situation Row can reentry the release probability of buffer resource corresponding to process, and the car that can reentry process during scheduled production for execution will turn back The buffer area dynamic reserved capacity to be entered, enable will execute the car that can reentry process smoothly turn back enter it is limited slow It rushes in area, is not detained in its current station, so that the probability blocked decline occurs in the station, reduce because of car contention Buffer resource and lead to serious continuous influence of the choking phenomenon to production process, reduce what deadlock situation in production process occurred Probability, to ensure that bus body painting Workshop Production process can be carried out smoothly.

To achieve the above object, the present invention, which solves the technical solution of technical problem, is:

Step 1: the Markov state transfer matrix based on bus body painting workshop historical production data is established, for predicting Process Oper can be reentried_rmUCorresponding buffer area bu resource discharges probability, is ready for buffer pool size is reserved.Pass through analysis The production history data in bus body painting workshop, process Oper can be reentried in the execution that will turn back of the interior car of unit time t ' by establishing_j(j =rmU) each station transition probability matrix P_y(y=1...M_U).Wherein

Indicate station WS at the beginning of unit time t '_{U, ku}The car of upper processing does not change, but passes through Cross unit time t ' later, the unchanged probability of the car processed on station.

Indicate station WS at the beginning of unit time t '_{U, ku}The car of upper processing does not change, but passes through Cross unit time t ' later, the probability that the car processed on station changes.

Indicate station WS at the beginning of unit time t '_{U, ku}The car of upper processing changes, but passes through Unit time t ' later, the unchanged probability of the car processed on station.

Indicate station WS at the beginning of unit time t '_{U, ku}The car of upper processing changes, but passes through Unit time t ' later, the probability that the car processed on station changes.

M_UIndicate that car turned back execution reentries process Oper_j(j=rmU) the parallel number of stations of maximum；WithTable In the case where showing that station processing car does not occur or changes at the beginning of unit time t ', when by unit Between t ' later, the car processed on station changes, i.e., the station free time must occurs and to be stored in and can weigh unit time t ' is interior Enter process Oper_rmUCar in corresponding buffer area bu is able to enter the station and is processed, meanwhile, buffer resource is released It discharges therewith.Therefore, it is considered as in varied situations, unit time t ' internal buffer resource discharges probability.

Step 2: judging whether that starting executes limited buffer dynamic capacity method for obligating, having for process can be reentried when having Limit buffer area bus body painting manufacture process proceeds to t moment, and production run state is as shown in Figure 1.If meeting following item Part thens follow the steps 3, calculates buffer resource and discharges probability.

1. in t moment, from the non-completion car J for reentrying process section_nrmTo enter process Oper_rmUBuffer area bu；

2. in t moment, process Oper_rmUBuffer area bu store car numberLess than buffer area bu maximum size BZS_U, AndI.e. in t moment, process Oper_rmUBuffer area residual capacity can only store a workpiece；

3. car execution of turning back can reentry production process Oper in t moment_rmUStation be in occupied state；

4. process Oper can be reentried in t moment_rmDStation on exist need to traverse the car that can reentry process section again；

5. on the basis of meeting above-mentioned 4 conditions, if process Oper can be reentried_rmUStation on the visitor that completes at first Vehicle J_UCompletion dateLess than production process Oper can be reentried_rmDIn the car J that completes at first_DCompletion time t₂, then Execute the subsequent operation of Network with Finite Buffers method for obligating.

Wherein, process Oper can be reentried_rmUIn the car that completes at first to enter the time of buffer area bd be t₁(t₁>=t), because To be likely to occur choking phenomenon under conditions of buffer pool size is limited, so will appear car J_UIt is still trapped in after completion to add Situation on work station can reentry process Oper_rmUIn the car J that completes at first_UInto the time t of buffer area bd₁It is more than or equal toProcess Oper can be reentried_rmDIn the car J that completes at first_DCompletion time be t₂。

If being unsatisfactory for above-mentioned condition, without executing the subsequent operation of Network with Finite Buffers method for obligating.Such as Fig. 1 institute Show.

Step 3: it will be turned back by prediction car and execute the situation of change for processing car on the station that can reentry process, i.e., it is slow Area resource release probability is rushed, to judge whether its corresponding buffering area residual capacity is that the car reentried is reserved.

In t moment, t is predicted by Prediction of Markov method₂Moment can reentry process Oper_rmUParallel station on most The car J first to complete_UPlace station WS_{U, ku}The changed probability P of the car of upper processing₂(i.e. prediction t₂Moment station WS_{U, ku}Add The probability of work difference car) and station WS_{U, ku}Upper processing car does not change, is constantly in by same car occupied state Probability P₁.Assuming that t₂Moment station WS_{U, ku}Process different cars, it is known that in t₂Before moment, process can be reentried by being stored in Oper_rmUCorresponding buffering area bu microbus entrance can reentry process Oper_rmUStation WS_{U, ku}In, then buffer resource is also therewith Release, in t₂Moment can reentry process Oper_rmDIn the car J that completes at first_DWhen being prepared to enter into buffer area bu, buffer area bu exists Residual capacity.Therefore, WS_{U, ku}Process the probability P of different cars₂It is equivalent to the probability of buffer area bu resource release.It is pre- by acquiring Survey t₂Moment station WS_{U, ku}Process the probability P of different cars₂And then obtain probability (the i.e. t of buffer area bu resource release₂Moment, Station WS_{U, ku}Process different car probability Ps₂), and then dynamic judges whether buffer area bu residual capacity is car J_DIt is reserved, it reduces Because of car J_nrmWith J_DBetween fight for buffer resource and generate the probability of deadlock situation.

Step 3.1: the car for executing and can reentrying and processing on the station of process of being turned back by calculating car is changed general Rate is obtained in the following t₂Moment buffer area bu resource discharges probability.

The probability of car variation of the t moment in the interior station processing of unit time t ' is calculated by the method for probability statistics a₂。

S₀=(a₁, a₂), (a₁+a₂=1) (2)

A in formula (2)₁Indicate that the production process data by analysis since production until t moment, statistics obtain 0 to t In the period at moment, station WS_{U, ku}The quantity of the upper processing unchanged unit time t ' of car was arrived with 0 in the time of t moment Ratio comprising unit time t ' sum, i.e., the probability occupied in t moment, the interior station of unit time t ' by same car.

A in formula (2)₂Indicate that the production process data by analysis since production until t moment, statistics obtain 0 to t In the period at moment, station WS_{U, ku}The quantity of unit time t ' that upper processing car changes and packet in 0 to t moment time The ratio of the sum of the t ' containing unit time, i.e., the probability occupied in t moment, the interior station of unit time t ' by different cars.

S₀Indicate the probability vector of the car processed in t moment, the interior station of unit time t ' variation.

Pass through current t moment station WS_{U, ku}The probability vector S of the car variation of upper processing₀It will calculate according to formula (3) in future t₂Moment station WS_{U, ku}The probability vector S of the car variation of upper processing_v, according to required result (i.e. in t₂Moment station WS_{U, ku}On The probability vector S of the car variation of processing_v) obtain process Oper_rmUIn the car J that completes at first_UThe station WS at place_{U, ku}It is upper to add The car of work does not change, is constantly in the probability P of occupied state₁(i.e. prediction t₂Moment, station WS_{U, ku}The probability of occupancy) With station WS_{U, ku}The changed probability P of the car of upper processing₂(i.e. prediction t₂Moment, process Oper_rmUBuffer resource release Put probability).

V indicates the sum in the time at t to t2 moment comprising unit time t ' in formula (3).

Step 3.2: showing that buffer resource discharges probability and determines that the car execution that will turn back can reentry work by step 3.1 Whether buffer area corresponding to sequence will reserve residual capacity for the car, and detailed process is as follows:

Process Oper can be reentried according to car execution of turning back has been found out_rmUThe car J to complete at first_UThe station at place WS_{U, ku}The changed probability of processing car (buffer resource release probability) judge buffer area bu residual capacity whether be Process Oper can be reentried_rmDIn the car J that completes at first_DIt is reserved.

If P₂≤P₁, t₂Moment station WS_{U, ku}The probability for processing different cars is lower, in t₂Buffer area bu is deposited before moment Process Oper can be reentried by putting car entrance_rmUStation WS_{U, ku}Probability it is lower, buffer resource is difficult to discharge, if buffer area bu Allow car J_nrmInto, seize buffer area bu unique resource, cause reentry car J_DCar with from the non-process section of reentrying Car J_nrmCompetition buffer resource fails and rests on its current station, causes the generation of choking phenomenon.If J_DPlace can weigh Enter process Oper_rmDThe car execution that all needs to turn back of other stations processing can reentry process Oper_rmU, then can cause continuously to hinder The generation of phenomenon is filled in, and then causes deadlock situation (as indicated with 2).With J_DBetween fight for buffer resource and cause deadlock situation, such as Shown in Fig. 2, therefore, process Oper can be reentried_rmUThe residual capacity of place buffer area bu is car J_DIt is reserved, meanwhile, from it is non-can Reentry the car J of process_nrmProcess section can be reentried by being prohibited from entering.

If P₂> P₁, indicate predicted, t₂Moment station WS_{U, ku}The probability for processing different cars is higher, in t₂Moment it Preceding buffer area bu storage car entrance can reentry process Oper_rmUStation WS_{U, ku}Probability it is higher, buffer resource is easy to get to releasing It puts.Work as t₂Moment can reentry process Oper_rmDIn the car J that completes at first_DWhen being prepared to enter into buffer area bu, buffer area bu has higher There may be residual capacities.Therefore in t moment, process Oper can be reentried_rmUBuffer area need not reserved capacity, therefore allow come From the non-car J for reentrying process_nrmInto process section can be reentried.

Step 4: if deviation occurs in prediction, (i.e. prediction buffer area bu resource release probable deviation, leads to J_nrmInto buffering Area bu, seizes unique resource, causes still generate deadlock situation in production process), to avoid going out for prediction deviation It is existing, process Oper can be reentried according to t moment_rmDThe execution that need to be turned back of whole stations can reentry process Oper_rmUReentry car account for Threshold alpha is set with rate, deviation compensation measure is added in the result of step 3.2.If step 3.2 show that prediction result allows to come From the non-car for reentrying process into process section can be reentried, then t moment is calculated, process Oper can be being reentried_rmDIn, occupying should (execution that needs to turn back again can reentry process Oper to the car of the station of process_rmUCar) quantity and process can be reentried Oper_rmDThe parallel number of stations M of the maximum for including_DRatio cc, meanwhile, generate range be (0,1) a random number r₁。

If P₂> P₁And r₁> α indicates the method by generating random number and threshold value comparison size, it is not necessary to step 3.2 Result carry out deviation compensation, then can reentry process Oper_rmUBuffer area bu residual capacity be not car J_DIt is reserved.

If P₂> P₁And r₁≤ α, indicates the method by generating random number and threshold value comparison size, and determination needs step 3.2 result carries out deviation compensation and (as makes up prediction and deviation, J occur_nrmDo not enter buffer area bu, process Oper can be reentried_rmU Buffer area bu residual capacity be car J_DIt is reserved).

If (car execution of turning back can reentry process Oper when α=1_rmDCar on station is needed all to traverse again and can be weighed Enter process), when opening, buffer area dynamic is reserved, it is possible that bus body painting workshop only has car to turn back execution at current time Process Oper can be reentried_rmUThere are residual capacity, other buffer pool sizes to be saturated for place buffer area.Meanwhile on each station There is car.If prediction result there is deviation, the execution that causes to turn back can reentry process Oper_rmUBuffer area existing for residue Parking stall is occupied from the non-car for reentrying process section, so that the buffer pool size that execution of turning back can reentry process section is equal Reach saturation, then will appear, which can reentry the car of process section, all rests on its current location, and then deadlock situation occurs, such as schemes Shown in 2.Random number r is judged if be added after the prediction result obtained at this time₁With the relationship of α, r₁Because of the shadow of its value range It rings and it is caused centainly to be less than α, so even if deviation occurs in the prediction result at current time, r₁< α also can make car that will turn back The buffer area residual capacity corresponding to process of reentrying executed is bound to as car J_DIt is reserved, and then avoid the prediction because of appearance Deadlock situation caused by result error.

Wherein correlation model parameters and variable are provided that

M_DIndicate that car execution of turning back can reentry process Oper_j(j=rmD) the parallel number of stations of maximum；

N indicates online processing car sum；

Indicate t moment, car J_iProcess is executed in process flow FL_qThe serial number of middle processing sequence, l ∈ 1 ... .., om_i}；

FL_qThe process flow for indicating processing car is production process microbus according to processing flow sequence process processing work The set of sequence；

om_iIndicate car J_iIn processing flow FL_qSum of the microbus Jing Guo manufacturing procedure, counterweight be added with the process of work into Row stored count, om_i≥m；

M indicates the total process number of Painting Shop；

Indicate t moment car J_i, in its process flow FL_qIt is middle to execute theA process, the process are that can reentry work Sequence Oper_rmU, in the station WS of the process_{U, ku}On end process time.

Step 5: according to the judging result of step 3.2 and step 4, it is determined whether executive buffer is that the car reentried is reserved Volume operation.

If showing that the car execution that will turn back can reentry process Oper by step 3.2 and step 4_rmUFor the car of reentry Reserved capacity, then from the non-car J for reentrying process section_nrmProcess section can be reentried by not entering, will not occupy limited buffer Residual capacity, remain in current station, therefore process Oper can be reentried_rmUCorresponding buffering area bu is to receive execution of turning back The car J of process can be reentried_DIt is ready.When production process proceeds to t₂When the moment, from process Oper can be reentried_rmDCar J_DCan enter can reentry process Oper_rmUIn corresponding buffer area bu, as shown in Figure 3.

If showing that the car execution that will turn back can reentry process Oper by step 3.2 and step 4_rmUIt is not necessarily reentry Car reserved capacity, then from the non-car J for reentrying process section_nrmInto process Oper can be reentried_rmUCorresponding buffering area bu, such as Shown in Fig. 4.

A kind of limited buffer dynamic capacity in having the bus body painting workshop that can reentry process proposed by the present invention is pre- Stay method flow as shown in Figure 5.

Advantages of the present invention and effect: the car processed on the station of process can be reentried by predicting that car will turn back to execute Change situation, that is, execution of turning back can reentry the release probability of buffer resource corresponding to process, executes during scheduled production The car of process can be reentried by the buffer area dynamic reserved capacity to be entered of turning back, the car that can reentry process will be executed by enabling Enough smoothly turn back enters in limited buffer, is not detained in its current station, so that blocking occurred in the station Probability decline, reducing leads to serious continuous influence of the choking phenomenon to production process because car fights for buffer resource, reduces The probability that deadlock situation occurs in production process, to ensure that bus body painting Workshop Production process can be carried out smoothly.

Detailed description of the invention

Fig. 1 is t moment bus body painting Workshop Production status diagram

Fig. 2 is bus body painting workshop deadlock situation schematic diagram

Fig. 3 is to turn back to execute to reentry the car of process and enter reserved buffer schematic diagram

Fig. 4 is can to reentry process section schematic diagram from the non-car entrance for reentrying process section

Fig. 5 is a kind of limited buffer dynamic capacity method for obligating in having the bus body painting workshop that can reentry process Flow diagram.

Fig. 6 is to meet bus body painting Workshop Production operating status when executing Network with Finite Buffers reservation operations condition to illustrate Figure

Fig. 7 is to turn back to execute the car that can reentry process into the buffer area schematic diagram for executing reservation operations for it

Specific embodiment

Step 1: the Markov state transfer matrix based on bus body painting workshop historical production data is established, for predicting Process corresponding buffering area resource release probability can be reentried, is ready for buffer pool size is reserved.By analyzing bus body painting vehicle Between production history data, process Oper can be reentried by establishing the car execution that will turn back in unit time t '=10_j(j=rmU) Each station transition probability matrix P_y(y=1...3).

Step 2: judging whether that starting executes limited buffer dynamic capacity method for obligating, having for process can be reentried when having Limit buffer area bus body painting manufacture process proceeds to the t=70 moment, and production run state is as shown in Figure 6.If meet with Lower condition, then execute Network with Finite Buffers reservation operations, and buffer area bu is allowed to be to execute the car reserved capacity that can reentry process.

1. from the non-completion car J for reentrying process section_nrmTo enter process Oper_rmUBuffer area bu；

2. t moment process Oper_rmUBuffer area bu store car numberLess than buffer area bu maximum size BZS_U= 2, and

3. car is turned back, execution can reentry production process Oper_rmUStation be in by car occupied state；

4. production process Oper can be reentried_rmDStation on exist need to traverse the car that can reentry process section again；

5. car execution of turning back can reentry process Oper on the basis of meeting above-mentioned 4 conditions_rmUIn at first complete Car J_UCompletion dateLess than process Oper can be reentried_rmDIn the car J that completes at first_DCompletion time t₂= 95Then start and executes limited buffer dynamic capacity reservation operations.Such as Fig. 6.

At the t=70 moment, t is predicted by Prediction of Markov method₂=95 moment, process Oper_rmUThe visitor to complete at first Station WS where vehicle JU_{U, ku}=WS_{U, 1}Process the changed probability P of car₂(i.e. prediction t₂=95 moment buffer area bu resources Discharge probability) and station WS_{U, 1}Processing car does not change, is constantly in the probability P of occupied state₁(i.e. prediction t₂When=95 Carve the probability that station occupies).

Step 3.1: the car for executing and can reentrying and processing on the station of process of being turned back by calculating car is changed general Rate is obtained in t₂=95 moment buffer area bu resources discharge probability.

The probability a of car variation of the t moment in the interior station processing of unit time t ' is calculated by the method for probability statistics₂ =0.48.

S₀=(0.52,0.48)

a_l=0.52 indicates that the production process data by analysis since production until t moment, statistics obtain 0 to t In the period at moment, station WS_{U, ku}The quantity of the upper processing unchanged unit time t ' of car was arrived with 0 in the time of t moment Ratio comprising unit time t ' sum, i.e., in t moment, the interior station of unit time t ' is by the probability that same car occupies 0.52。

a₂=0.48 indicates that the production process data by analysis since production until t moment, statistics obtain 0 to t In the period at moment, station WS_{U, ku}The quantity of unit time t ' that upper processing car changes and packet in 0 to t moment time The ratio of the sum of the t ' containing unit time, i.e., in t moment, the probability that the interior station of unit time t ' is occupied by different cars is 0.48.

S₀=(0.58,0.42) indicates in t moment, the probability of the car variation of the interior station processing of unit time t ' to Amount.

Pass through current t=70 moment station WS_{U, 1}The probability vector S of the car variation of upper processing₀=(0.52,0.48) according to It calculates according to formula (3) in the following t₂=95 moment station WS_{U, 1}The probability vector S of the car variation of upper processing_v=(0.54,0.46), According to required result (i.e. t₂Moment station WS_{U, ku}The probability vector S of the car variation of upper processing_v=(0.54,0.46)), it obtains Process Oper_rmUIn the car J to complete at first_UThe station WS at place_{U, 1}The car of upper processing does not change, is constantly in and accounts for With the probability P of state₁=0.54 (i.e. prediction t₂=95 moment station WS_{U, 1}The probability of occupancy) and station WS_{U, 1}The car of upper processing Changed probability P₂=0.46 (i.e. prediction t₂=95 moment buffer area bu resource release rates).Calculate probability vector S_vProcess It is as follows:

Find out (P₁, P₂)=(0.54,0.46).

V=3 indicates t moment to t₂It include the sum of unit time t ' to round up in period at moment, wherein t= 70, t₂=95, t '=10.

Process Oper can be reentried according to car execution of turning back has been found out_rmUThe car J to complete at first_UThe station at place WS_{U, 1}The changed probability P of the car of upper processing₂=0.46 (buffer resource release probability) judges the residue of buffer area bu Whether capacity is that can reentry process Oper_rmDIn the car J that completes at first_DIt is reserved.

If P₂≤P₁, indicate predicted, work as t₂=95 moment, which came from, can reentry process Oper_rmUAll stations at first The car J of completion_UThe station WS at place_{U, 1}The car of upper processing does not change, and buffer resource is difficult to discharge, then can reentry Process Oper_rnUThe residual capacity of place buffer area bu is car J_DIt is reserved, from the non-car J for reentrying process_nrmDo not enter Process section can be reentried, its current station is rested on.

If P₂> P₁, indicate predicted, work as t₂=95 moment, which came from, can reentry process Oper_rmUAll stations at first The car J of completion_UThe station WS at place_{U, 1}The car of upper processing changes, and buffer resource is easily released.Work as t₂When=95 Quarter can reentry process Oper_rmDIn the car J that completes at first_DWhen being prepared to enter into buffer area bu, buffer area bu has and higher may deposit In residual capacity.Therefore at the t=70 moment, process Oper can be reentried_rmUBuffer area need not reserved capacity, therefore allow from non- The car J of process can be reentried_nrmInto process section can be reentried.

Step 4: if deviation occurs in prediction, deadlock situation still may be generated in production process, it is pre- to avoid Deviation compensation measure is added in the appearance for surveying deviation in the result of step 3.2.If step 3.2 show that prediction result allows to come From the non-car for reentrying process into process section can be reentried, then the t=70 moment is calculated, process Oper can be being reentried_rmDIn, it accounts for With the car of the station of the process, (execution that needs to turn back again can reentry process Oper_rmUCar) quantity be 2, work can be reentried Sequence Oper_rmDThe parallel number of stations M of the maximum for including_D=3, the ratio of the twoMeanwhile generate range be one of (0,1) with Machine number r₁=0.4.

If P₂> P₁And r₁≤ α can then reentry process Oper_rmUBuffer area bu residual capacity be car J_DIt is reserved.

If P₂> P₁And r₁> α can then reentry process Oper_rmUBuffer area bu residual capacity will not be car J_DIn advance It stays.

Step 5: step 5: according to the judging result of step 3.2 and step 4, it is determined whether executive buffer is the visitor reentried The operation of vehicle reserved capacity.

Work Oper can be reentried based on the execution that will turn back of car calculated by step 3.2_rmUCorresponding buffering area residual capacity is attached most importance to Reserved result (the P of the car entered₂=0.46 < P₁=0.54).From the non-car J for reentrying process section_nrmBeing prohibited from entering can It reentries process section and rests in its current station.Process Oper can be reentried_rmUResidual capacity can reentry process for the execution that will turn back Oper_rmUCar J_DIt is reserved.Production process proceeds to t₂=95 moment completed process Oper_rmDThe car J of processing_DIt turns back entrance Process Oper can be reentried_rmUIn corresponding buffer area bu, as shown in Figure 7.

Claims

1. a method for reserving dynamic capacity of limited buffer zone in the paint shop for passenger cars with re-entry operation, it is characterized in that: described method contains the following steps successively:

Step 1: Establish a Markov state transition matrix based on the historical production data of the bus painting workshop, which is used to predict the release probability of the buffer bu resource corresponding to the re-entrant process Oper _rmU , and prepare for the buffer capacity reservation;

Step 2: Determine whether to start and execute the limited buffer dynamic capacity reservation method. When the production process of the limited buffer bus painting workshop with re-entrant processes reaches time t, if the conditions are met, step 3.1 is executed to calculate the buffer resources. Release probability; if the above conditions are not met, there is no need to perform subsequent operations of the limited buffer capacity reservation method;

Step 3: Determine whether the remaining capacity of the corresponding buffer zone is reserved for the re-entrant passenger car by predicting the change of the passenger car processing at the station where the passenger car will return to the re-entry process, that is, the buffer resource release probability;

Step 3.1: By calculating the probability of the change of the bus processed at the station where the bus returns to the re-entrant process, the release probability of the buffer bu resource at time t ₂ in the future is obtained;

Step 3.2: Through step 3.1, the buffer resource release probability is obtained to determine whether the passenger car will return to the buffer corresponding to the re-entrant process to reserve the remaining capacity for the passenger car,

Step 4: Determine whether it is necessary to add deviation compensation measures to the results of Step 3.2;

Step 5: According to the judgment results of Step 3.2 and Step 4, determine whether to perform the operation of reserving the buffer capacity for the re-entrant passenger car.

2. a kind of limited buffer dynamic capacity reservation method in the passenger car paint shop with re-entry process according to claim 1, is characterized in that: by analyzing the production history data of the passenger car paint shop, based on the unit time In t', the passenger car will return to each station transition probability matrix P _y (y=1...M _U ) to execute the re-entrant process Oper _j (j=rmU). in

Represents the probability that at the beginning of the unit time t', the passenger cars processed on the stations WS _{U and ku} have not changed, but after the unit time t', the passenger cars processed on the stations have not changed;

Indicates that at the beginning of the unit time t', the bus processed on the stations WS _{U, ku} does not change, but after the unit time t', the probability that the bus processed on the station changes;

Represents the probability that at the beginning of the unit time t', the buses processed at the stations WS _{U, ku} change, but after the unit time t', the buses processed at the stations remain unchanged;

Indicates that at the beginning of unit time t', the bus processed on the station WS _{U, ku} changes, but after the unit time t', the probability of the bus processed on the station changes;

M _U represents the maximum number of parallel stations of the re-entrant process Oper _j (j=rmU) performed by the passenger car turn-back;

and Indicates that at the beginning of the unit time t', if the processing of the passenger car at the station does not occur or changes, after the unit time t', the passenger car processed at the station changes, that is, the station must appear within the unit time t'. Idle allows the bus stored in the buffer bu corresponding to the reentrant process Oper _rmU to enter the station for processing, and at the same time, the buffer resources are also released. Therefore, it can be regarded as the release probability of buffer resources within unit time t' under different circumstances.

3. a kind of limited buffer dynamic capacity reservation method in the passenger car paint shop with re-entry procedure according to claim 1, is characterized in that: when the limited buffer zone passenger car paint shop with re-entry procedure is produced When the process reaches time t, the production operation status is shown in Figure 1. If the following conditions are met, step 3 is performed to calculate the buffer resource release probability;

At time t, the completed passenger car J _nrm from the non-reentrant process section will enter the buffer bu of the process Oper _rmU ;

At time t, the buffer bu of the process Oper _rmU stores the number of passenger cars is less than the upper limit of buffer bu capacity BZS _U , and That is, at time t, the remaining capacity of the buffer of the process Oper _rmU can only store one workpiece;

At time t, the stations where the bus returns to perform the re-entrant production process Oper _rmU are all occupied;

At time t, there is a bus that needs to traverse the re-entrant process section again on the station of the re-entrant process Oper _rmD ;

On the basis of satisfying the above 4 conditions, if the re-entry process Oper _rmU station is the first completed bus _JU , the completion time If it is less than the completion time t ₂ of the first completed passenger car J _D in the reentrant production process Oper _rmD , the subsequent operations of the limited buffer capacity reservation method are performed.

4. a kind of limited buffer dynamic capacity reservation method in a passenger car paint shop with re-entry procedure according to claim 1, is characterized in that: at time t, time t ₂ is predicted by Markov prediction method, The probability P 2 that the bus J _U that is first completed on the parallel station of the re-entrant process Oper _rmU is located at the station WS _{U, and} the probability P ₂ of the bus processed on ku changes (that is, it is predicted that the processing of stations WS _{U and ku} will be different at time t ₂ ) The probability of the passenger car) and the station WS _{U, ku} processing the passenger car have not changed, the probability P ₁ has been in the state of being occupied by the same passenger car. Assuming that the stations WS _{U and ku} process different passenger cars at time t ₂ , it can be known that before time t ₂ , the passenger cars stored in the buffer bu corresponding to the re-entrant process Oper _rmU enter the stations WS _{U, ku} of the re-entrant process Oper _rmU . , the buffer resources are also released accordingly. When the first completed passenger car _JD in the re-entry process Oper _rmD is ready to enter the buffer bu at time _t2 , the buffer bu has remaining capacity. Therefore, the probability P ₂ of WS _{U, ku} processing different passenger cars is equivalent to the probability of the release of the buffer bu resources. By obtaining and predicting the probability P ₂ of processing different passenger cars at the stations WS _{U and ku} at the time of t ₂ , the probability of releasing the buffer bu resources is obtained (that is, at t ₂ , the probability P ₂ of processing different passenger cars at the stations WS _{U and ku} ), and then Dynamically determine whether the remaining capacity of the buffer bu is reserved for the passenger car J _D , reducing the probability of deadlock caused by the competition between the passenger car J _nrm and J _D for buffer resources,

Calculate the probability a ₂ of the bus processed by the station within the unit time t' at time t by means of probability statistics,

S ₀ =(a ₁ , a ₂ ), (a ₁ +a ₂ =1) (2)

In formula (2), a ₁ indicates that by analyzing the production process data from the start of production to time t, statistics can be obtained from 0 to time t, the unit time t' that the passenger car is processed on the station WS _{U, ku} does not change. The ratio of the number of t to the total number of times t' including unit time t', that is, at time t, the probability that the station is occupied by the same bus in unit time t'.

In formula (2), a ₂ indicates that by analyzing the production process data from the start of production to time t, it is statistically obtained that in the time period from 0 to time t, the unit time t' for the processing of passenger cars on stations WS _{U, ku} changes. The ratio of the number to the total number of unit time t' included in the time from 0 to time t, that is, at time t, the probability that the station is occupied by different passenger cars within the unit time t'.

S ₀ represents the probability vector of the change of the passenger cars processed at the station in unit time t' at time t,

Through the probability vector S ₀ of the change of the passenger car processed on the station WS _{U, ku} at the current time t, according to formula (3), the probability vector S _v of the change of the passenger car processed on the station WS _{U, ku} at time t ₂ in the future is calculated. Obtain the result (that is, the probability vector S _v of the change of the passenger car processed on the station WS _{U, ku} at time t ₂ ) to obtain the station WS _U of the first completed passenger car JU in the process Oper _rmU , and the passenger car processed on the _ku is not yet. The probability P ₁ that has been in the occupied state (that is, the probability that the station WS _{U, ku} is occupied at time t ₂ ) and the probability P ₂ of the passenger car processed on the station WS _{U, ku} are changed (that is, the probability of predicting t ₂ time, the buffer resource release probability of the process Oper _rmU ),

In formula (3), v represents the total number of unit time t' included in the time from t to t2,

According to the obtained buffer resource release probability, it is determined whether the buffer corresponding to the reentrant process of the bus will be turned back to reserve the remaining capacity for the bus. The specific process is as follows:

The remaining capacity of the buffer bu is determined according to the probability that the processing passenger car WS _U _{and ku} of the first completed passenger car JU that has been turned back to perform the re-entrant process Oper _rmU are located. Whether it is reserved for the first completed passenger car _JD in the re-entrant process Oper _rmD .

If P ₂ ≤ P ₁ , the probability of processing different passenger cars at the stations WS _{U, ku} at time t ₂ is relatively low, and the probability that the passenger cars are stored in the buffer bu before the time t ₂ enters the re-entrant process Oper _rmU station WS _{U, ku} is relatively high. If the buffer is low, it is difficult to release the buffer resources. If the buffer bu allows the passenger car J _nrm to enter, it will preempt the only resource of the buffer bu, resulting in the reentrant passenger car J _D and the passenger car J _nrm from the non-reentrant process segment competing for buffer resources and failing. stay in its current position, causing the occurrence of blocking phenomenon. If all the passenger cars processed by the re-entrant process Oper _rmD where J _D is located need to be turned back to perform the re-entrant process Oper _rmU , it will cause continuous blocking and lead to deadlock phenomenon (as shown in 2). As shown in Figure 2, the deadlock is caused by competing for buffer resources with J _D. Therefore, the remaining capacity of the buffer bu where the reentrant process Oper _rmU is located is reserved for the passenger car J _D. At the same time, it comes from the non-reentrant process. The passenger car J _nrm is prohibited from entering the re-entrant process section.

If P ₂ >P ₁ , it means that it is predicted that the probability of processing different passenger cars at the stations WSU _{and ku} at time _t2 is relatively high. Before time _t2 , the buffer bu stores the passenger cars and enters the re-entry process Oper _rmU station WSU _, The probability of _ku is high, and the buffer resources are easily released. When the first completed passenger car J _D in the re-entrant process Oper _rmD is ready to enter the buffer bu at time t ₂ , the buffer bu has a high possibility of remaining capacity. Therefore, at time t, the buffer of the re-entrant process Oper _rmU does not need to reserve capacity, so the passenger car J _nrm from the non-re-entrant process is allowed to enter the re-entrant process section.

5. a kind of limited buffer dynamic capacity reservation method in the passenger car paint shop with re-entrant operation according to claim 1 is characterized in that: if the prediction occurs deviation (i.e. prediction buffer bu resource release probability deviation, Causes J _nrm to enter the buffer bu, preempting the only resource, which may lead to deadlock phenomenon in the production process), in order to avoid the occurrence of prediction deviation, according to the time t, the re-entry process Oper _rmD all stations are required to return to the execution and can be repeated. The threshold α is set for the occupancy rate of the re-entry bus in the entry process Oper _rmU , and the deviation compensation measures are added to the results of step 3.2. If the prediction result obtained in step 3.2 allows the passenger car from the non-reentrant process to enter the re-entrant process section, then calculate the time t, in the re-entrant process Oper _rmD , the passenger car occupying the station of the process (need to be re-entered to execute The ratio α of the number of passenger cars of the reentrant process Oper _rmU ₎ to the maximum number of parallel stations MD contained in the reentrant process Oper _rmD , and at the same time, a random number r ₁ in the range of (0, 1) is generated.

If P ₂ >P ₁ and r ₁ >α, it means that by generating a random number and comparing the size of the threshold, it is not necessary to perform deviation compensation on the result of step 3.2, and the remaining capacity of the buffer bu of the re-entry process Oper _rmU is not a passenger car J _D reserved.

If P ₂ >P ₁ and r ₁ ≤α, it means that by generating a random number and comparing the size of the threshold, it is determined that the result of step 3.2 needs to be compensated for deviation (that is, in order to compensate for the deviation of the prediction, J _nrm does not enter the buffer bu, it can be The remaining capacity of the buffer bu of the re-entry process Oper _rmU is reserved for the passenger car J _D ).

If α=1 (that is, when the bus is turned back to execute the re-entrant process, all the buses at the Oper _rmD station need to traverse the re-entrant process again), when the buffer dynamic reservation is enabled, it may happen that the bus paint shop has only There is remaining capacity in the buffer where the reentrant process Oper _rmU is located, and the capacity of other buffers is saturated. At the same time, there are buses at each station. If there is a deviation in the predicted result, the remaining parking spaces in the buffer of the reentrant operation Oper _rmU will be occupied by the passenger cars from the non-reentrant operation section, so that the buffer capacity of the reentrant operation section will reach If it is saturated, the passenger cars that can re-enter the process section will all stay at their current positions, and then a deadlock phenomenon will occur, as shown in Figure 2. At this time, if the relationship between the random number r ₁ and α is added after the obtained prediction result, r ₁ must be smaller than α due to the influence of its value range, so even if the prediction result at the current moment is deviated, r ₁ < α will also make the remaining capacity of the buffer corresponding to the re-entrant process that the passenger car will perform by turning back to be reserved for the passenger car _JD , thereby avoiding the deadlock phenomenon caused by the deviation of the predicted results.

The relevant model parameters and variables are set as follows:

MD represents the maximum number of parallel stations for the reentrant process Oper _j (j= _rmD ) performed by the passenger car turning back;

n represents the total number of on-line processing buses;

l _i ^t represents the sequence number of the processing sequence in the process flow FL _q of the passenger car J _i at time t, l∈{1,.....,om _i };

FL _q represents the technological process of processing passenger cars, which is a collection of processing procedures that passenger cars go through in the order of the technological process during the production process;

om _i represents the total number of processing steps of the passenger car J _i in the processing flow FL _q , and counts the repeated processing steps cumulatively, om _i ≥ m;

m represents the total number of processes in the painting workshop;

Indicates that the passenger car J _i at time t performs the first step in its technological process FL _q A process, this process is a re-entrant process Oper _rmU , the end processing time on the work station WS _{U, ku} of this process.