JPH07160773A - Production planning device - Google Patents

Abstract

PURPOSE:To provide a production planning device capable of effectively plan ning a schedule and easily allowing an actual production system and a constructed modem to correspond to each other. CONSTITUTION:The device consists of transition (N-TR) capable of optimally setting a fire continuing time and transistion (0-TR) having nonfirable attributes and uses operation units corresponding to operation executed in each facility. Then, the device is provided with a model input device (101) inputting the symbol (icon expression) of a production process, a model generation device (103) connecting the units of Petri net expression in accordance with the inputted symbol, a result correction device (212) collecting a result from an actual production process, an initial condition setting system (211) setting an initial condition to the Petri net expression of the production process based on information from the result collection system and a competition eliminating device (202) eliminating competition when competition is generated while executing simulation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a production planning apparatus using a Petri net model, and in particular, makes it easy to create and modify a Petri net model, and supports rescheduling and dynamic scheduling due to diving or equipment stoppage. The present invention relates to a production planning device.

[0002]

2. Description of the Related Art Modeling by Petri nets is known as one of powerful methods for performing analysis of information flow and state analysis in a discrete event system such as a production system. (Reference: “Introduction to Petri Net” author J. L. Pitasun, Kyoritsu Shuppan Co., Ltd.) However, the one disclosed in the above-mentioned reference is that the model of the entire production system is modeled as a whole, so that the model construction The problem was that it was very complicated.

Therefore, the inventors can solve the above-mentioned problems and can promptly and efficiently respond to changes in products to be produced, accidents such as machine failure, and addition or reduction of buffers. A production system simulator device using a Petri net capable of simulating in the opposite direction of production progress from the arrangement and time of a certain token (Japanese Patent Laid-Open No. 5-2
No. 33590) is proposed.

[0004]

However, the above-mentioned Japanese Unexamined Patent Application Publication No.
The one disclosed in No. 233590 has the following problems.

1) Since the production system is divided into each element and modeled, it is difficult to make correspondence between the actual production system and the constructed model.

2) In an actual production system, re-scheduling or dynamic scheduling is required due to a jump or the like, but actual data from the manufacturing process cannot be collected and set in real time. Can't do.

3) Since the working time is fixed, it is impossible to perform scheduling considering variable time such as setup time.

4) Since the elapsed time is realized by the transition of the fixed ignition duration, when the model is created in the memory of the computer system, the required memory point is estimated unless all the working times are determined. If it is not possible and there are many processes that require a long working time, a huge memory capacity is required.

5) Since a transition is configured to follow a complete self-ignition rule that tokens exist in all the places on the input side of a transition, this transition is inevitable to be checked for duplication. , Simulation takes time. Further, actually, even when a schedule with a better evaluation can be created as a result of waiting for the start of processing, the schedules are sequentially created, and effective scheduling cannot be performed.

Therefore, in the present invention, it is easy to make correspondence between the actual production system and the constructed model,
Providing a production planning device that can support rescheduling and dynamic scheduling, can perform scheduling considering variable time such as setup time, can significantly reduce memory capacity, and can perform effective scheduling The purpose is to do.

[0011]

In order to achieve the above-mentioned object, the present invention is a production planning apparatus for producing a production plan by executing a simulation using a Petri net model. When there are transitions in which the ignition conflicts in the model, a conflict resolution means for eliminating the conflict based on previously stored conflict resolution knowledge is provided.

Further, the present invention, in a production planning apparatus for creating a production plan by executing a simulation using a Petri net model, actual performance information for collecting actual performance information from the production equipment which is the target of the Petri net model. It is characterized by comprising: a collecting means; and an initial condition setting means for setting an initial condition of the simulation of the Petri net model corresponding to the performance information collected by the performance information collecting means.

Further, the present invention is a production planning apparatus for creating a production plan by executing a simulation using a Petri net model, comprising: a simulation apparatus for executing the simulation. Is a means for extracting a transition that can be ignited from the Petri net model, a competition determination means for checking whether there is a transition that cannot be ignited by the ignition of the ignitable transition extracted by the extraction means, and When it is determined by the conflict determination means that there is a transition that cannot be fired, it is determined that a conflict has occurred and the conflict resolution requesting means for requesting the conflict resolution device to resolve the conflict and the conflict resolution information from the conflict resolution device are received. And means for eliminating the conflict.

Further, the present invention is a production planning apparatus for creating a production plan by executing a simulation using a Petri net model, comprising: a simulation apparatus for executing the simulation. Is extraction means for extracting a transition that can be ignited from the Petri net model, and ignites the transition that can be ignited extracted by the extraction means,
If the ignited transition is a transition that corresponds to the start of a work unit, an ignitable attribute adding means that gives an ignitability attribute for one unit time and an ignitable transition extracted by the extraction means are a transition that corresponds to the end of the work unit. If there is any, the non-ignition attribute cancellation means for canceling the non-ignition attribute and the ignition time recording means for recording the ignition time of the ignitionable transition extracted by the extraction means are provided.

Further, the present invention is a production planning apparatus for creating a production plan by executing a simulation using a Petri net model, comprising a simulation apparatus for executing the simulation, and the Petri net. The model comprises a variable time transition whose ignition duration can be set to an arbitrary value, and the simulation device extracts the variable time transition from the Petri net model and the extraction means. An ignition duration setting means for setting the ignition duration of the variable time transition to ignite, and an ignition time recording means for recording the ignition time of the transition ignited by the ignition duration setting means. To do.

Further, according to the present invention, in a production planning apparatus for creating a production plan by executing a simulation using a Petri net model, after the completion of the above-mentioned simulation, the production plan is set to a time base of the firing time of each transition. Plan output means for outputting as a Gantt chart arranged according to the above.

Further, according to the present invention, in a production planning apparatus for producing a production plan by executing a simulation using a Petri net model, a display means and a model producing means for producing the Petri net model are provided. The model generation means arranges the storage means for storing the generated model, the input means for inputting the manufacturing process symbol, and the manufacturing process symbol input by the input means on the screen of the display means. Means and a symbol for each manufacturing process arranged on the screen are sequentially selected to create a storage area for storing a data structure corresponding to each unit of the Petri net model represented by the selected manufacturing process symbol. Means for securing in the storage means, and means for inputting data of each manufacturing process in the storage area secured in the storage means Characterized by comprising means for generating the Petri net model by connecting each unit corresponding to each symbol that is selected on the screen.

[0018]

According to the present invention, when there is a transition in which the firings in the Petri net model conflict due to the simulation, the conflict resolution means resolves the conflict based on the conflict resolution knowledge stored in advance.

Here, the conflict resolution knowledge can be configured to give priority to the ignition of a transition corresponding to a manufacturing process having a short working time when the production deadline is short, and the conflict resolution knowledge can be produced by the production. If the delivery time is long, it is possible to prioritize the ignition of the transition corresponding to the manufacturing process that arrives earlier.

Further, according to the present invention, the performance information collecting means collects performance information from the production equipment which is the target of the Petri net model, and the initial condition setting means corresponds to the collected performance information of the Petri net model. Set the initial conditions for simulation. Here, the above performance information is
Work-in-process information indicating the type of work-in-process and remaining work time in the production facility, or work-in-process information indicating the type and number of work-in-process in the buffer in the preceding stage of the production facility. You can

The initial condition setting means removes the talk from the place of the work unit corresponding to the work of the Petri net model, sets the transition firing duration of the work unit to the remaining work time, and , If the token is reduced from the place of the buffer unit corresponding to the buffer of the Petri net model, the token is added to the place of the connection unit corresponding to the buffer, and the production facility is stopped,
When the token is deleted from the place of the equipment unit corresponding to the production equipment of the Petri net model, the simulation of the production equipment is prohibited, and when the manufacturing order is added, the input product unit of the Petri net model is added. Add a token corresponding to the added order to the place.

Further, in the present invention, a simulation device for performing simulation is provided, and the simulation device extracts an ignitable transition from the Petri net model by the extraction means, and the competition determination means, It is checked whether there is a transition that cannot be fired due to the firing of the extracted ignitable transition. Then, if there is a transition that cannot be fired, it is determined that a conflict has occurred, and the conflict resolution requesting unit requests the conflict resolution device to resolve the conflict, and receives the conflict resolution information from the conflict resolution device. Resolve conflicts.

Further, the present invention comprises a simulation device for performing simulation, and the simulation device extracts ignitable transitions from the Petri net model by the extraction means and adds an ignitable attribute. By means of igniting the extracted ignitable transition, if the ignited transition is a transition that corresponds to the start of the work unit, an ignitable attribute of 1 unit time is attached, and the ignitable attribute releasing means,
If the extracted ignitable transition is a transition that is the end of the work unit, the ignitable attribute is canceled. And, by the ignition time recording means,
The ignition time of the ignitable transition extracted by the extraction means is recorded.

Further, in the present invention, a simulation device for executing simulation is provided, and
The Petri net model has a variable time transition that can set the firing duration to an arbitrary value, and the simulation device extracts the variable time transition from the Petri net model by the extraction means and uses the firing duration setting means. The ignition duration of the extracted variable time transition is set and fired. Then, the firing time recording means records the firing time of the fired transition.

Further, in the present invention, after the completion of the simulation, the plan output means outputs the production plan as a Gun chart in which the ignition times of the respective transitions are arranged on the time axis.

Further, in the present invention, display means,
A model generating means for generating a Petri net model, wherein the model generating means inputs the symbol of the manufacturing process by the input means and arranges the input symbol of the manufacturing process on the screen of the display means, By sequentially selecting symbols of each manufacturing process arranged on the screen, a storage area for storing a data structure corresponding to each unit of the Petri net model represented by the selected manufacturing process symbol is stored on the storage means. A Petri net model is generated by securing and inputting data of each manufacturing process into the secured storage area on the storage means, and connecting each unit corresponding to each symbol selected on the screen.

Here, the symbol can be composed of symbols indicating, for example, 1) input product, 2) output product, 3) equipment, 4) buffer.

The arrangement on the screen is such that the symbol indicating the input product is the starting point, the symbol indicating the output product is the end point, and the symbol indicating the input product and the symbol indicating the output product are the above. A symbol indicating equipment and a symbol indicating the above buffer are arranged.

Corresponding to the selection of a symbol on the screen, the symbol indicating the input product is used as a starting point,
A line leading to the symbol indicating the output product at the end point through the symbol indicating the facility and the symbol indicating the buffer is displayed on the screen.

Each of the above units is constructed by combining the basic elements of Petri nets.

Each unit can be composed of 1) an input product unit, 2) an output product unit, 3) a working unit, 4) a buffer unit, and 5) a connection unit.

Here, the Petri net model is generated with the input product unit as a starting point and the output product unit as an end point, and the working unit and the output product unit are provided between the input product unit and the output product unit. A buffer unit and the above connection unit are combined and connected.

As described above, according to the present invention, the elements of the production system (equipment, buffer, input and output of products) can be arranged on the screen of the computer system in the same manner as the physical arrangement of the production system. By doing so, the model and the production process can be associated with each other.

Further, when the arranged production system is clicked with the input device (mouse) in the order of passage of the products manufactured by using the production system, the processing time at the target equipment can be inputted.

Further, when the Petri net model is created, it is necessary to introduce the concept of a work unit using a variable time transition in which the firing duration can be freely set for the work executed on each facility. The memory capacity can be reduced, the required memory capacity can be roughly estimated from the total number of operations, and variable time factors such as setup change can also be supported.

Further, by providing a non-ignition attribute to the transition, it is possible to shorten the simulation time and delay the start of the work for a specific time by preventing duplicate checks of non-ignition transitions according to the spontaneous firing rules.

Further, by using a POP (Point Of Production) system from the equipment and buffer of the actual manufacturing process, the product information during processing, the remaining processing time, the product type and the number of products in the buffer are obtained, and the Petri net is obtained. By giving initial conditions to the model, it is possible to deal with rescheduling and dynamic scheduling due to jumping in or facility stoppage.

[0038]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of a production planning apparatus according to the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows a schematic system configuration of a production planning apparatus according to the present invention. In FIG. 1, the production planning apparatus includes a model creating unit 100 that creates a Petri net model corresponding to a production process, and a simulation unit 200 that executes a simulation based on the Petri net model created by the model creating unit 100. It has.

Here, the model creating section 100 includes a model input device 101, a display device 102, and a model creating device 103.
The simulation unit 200 includes a simulation device 201, a plan display device 202, and a conflict resolution device 203.

This production planning apparatus also includes a setup change information storage device 111 for storing equipment setup change information, a model information storage device 112 for storing model information input from the model input device 101, and a conflict resolution device 203. It has a conflict resolution knowledge database 214 for storing conflict resolution knowledge for the conflict resolution process.

Further, this production planning system is provided with an initial condition setting system 211 for executing simulation in the simulation system 201 and a performance collection system 212 for collecting performance information from the production facility 213.

In FIG. 1, the model input device 101 is
A device for inputting a model of the manufacturing process, which corresponds to a keyboard or mouse of a computer system. In the apparatus of this embodiment, the model of the manufacturing process is input using the model input device 101, and the model input by the model input device 101 is displayed on the display device 102.

The input items input by the model input device 101 are as follows: 1) facility arrangement and capacity of the manufacturing process, setup table, 2) buffer configuration and capacity of the manufacturing process, 3) products passing through the process, product number, etc. Is.

The display device 102 is the model input device 101.
This is a device for displaying the model input in step S1, and corresponds to a CRT, a printer, etc. of a computer system. The display device 102 displays the state of the model input from the model input device 101.

The model generation device 103 builds a manufacturing process model (Petri net model) on the memory based on the information input from the model input device 101.

Of the information input from the model input device 101, the equipment setup change information is stored in the setup setup information storage device 111.

Information on the model constructed by the model generation device 103 is stored in the model information storage device 112.

By the way, in this embodiment, the model generating device 103 generates a Petri net model from each unit in which the basic elements of the Petri net are combined.

The following are examples of each unit in which the basic elements of this Petri net are combined. 1) Input product unit 2) Output product unit 3) Working unit 4) Equipment unit 5) Buffer unit 6) Connection unit

FIG. 2 shows the basic elements of the Petri net used in this embodiment, where 301 is a place (PL), and 302 is a transition (TR or 0-TR) whose firing duration is 0. ), 303 is a variable time transition (N-
TR), 304 indicates an arc, and 305 indicates a token.

FIG. 3 shows a concrete configuration of each unit of this embodiment constructed by combining the basic elements of the Petri net shown in FIG.

In FIG. 3, an equipment unit is shown in FIG. 3A, and this equipment unit 410 is a place 41.
1 and a token 412 placed in this place 411.

Further, FIG. 3B shows the buffer unit 4
20, the buffer unit 420 is composed of a place 421 and two tokens 422 and 423 placed in the place 421.

Further, FIG. 3C shows a connection unit 430, which is composed of a place 431, an arc 432 directed to the place 431, and an arc 433 directed outward from the place 431.

FIG. 3D shows the input product unit 44.
0, this input product unit 440 is placed in place 4
41 and transition (0-TR) 442 and place 4
It is composed of an arc 443 traveling from 41 to the transition (0-TR) 442. Further, FIG. 3E shows a work unit 450, and this work unit 450 has a place (451-452, 453) and a transition (0-T).
R) 454, 457, transition (N-TR) 45
5, 456 and a plurality of arcs connecting between each place and each transition. Here, the transition (0-TR) 454 can have a non-firing attribute, the transition (N-TR) 455 represents a setup change time, and the transition (N-TR) 456 represents an actual work time. In addition, transition (N-TR)
The firing duration of each of 455 and transition (N-TR) 456 can be arbitrarily changed.

FIG. 3 (f) shows the output product unit 46.
0, this output product unit 460 comprises a transition (0-TR) 461, a place 462, and an arc 463 from the transition (0-TR) 461 to the place 462. 4 to 6 show transition firing conditions used in this embodiment.

In the state shown in FIG. 4, the transition (0-TR) cannot be fired because it has no token in one place on its input side (transition firing condition 1).

In the state of FIG. 5, the transition (0-TR) is fired because it has tokens in both places on its input side (transition firing condition 2). However, in this embodiment, the transition (0-TR) can have a unit time ignitable attribute, and in this case, even if the transition (0-TR) becomes an ignitable state as shown in FIG. Does not catch fire.
This transition (0-TR) fires only when the non-firing attribute is released.

FIG. 6 shows a variable time transition (N-T
The operation of R) is shown. Variable time transition (N-T
R) fires when it has a token in both places on its input side, as shown in FIG. 6, but the firing continues for a set time, and the firing ends when the set time elapses. Here, the ignition duration time can be arbitrarily changed.

Returning to FIG. 1, the simulation device 201.
Performs simulation using the Petri net model created by the model creating unit 100. Specifically, the simulation device 201 refers to the stored information in the setup change information storage device 111 and the model information storage device 112 based on the output of the model creation unit 100 and the output of the initial condition setting device 211 described later, and performs the simulation. To execute. The result of the simulation performed by the simulation device 201 becomes the plan of the manufacturing process by the device.

If a conflict occurs during execution of the simulation, the simulation device 201 requests the conflict resolution device 203 to prioritize the conflict. Then, the conflict is resolved based on the priority ranking of the conflict determined by the conflict resolution device 203, and the simulation is continued.

The conflict resolving device 203 is a device for resolving the conflict that has occurred in the simulation device 201. Based on the conflict resolving knowledge stored in the conflict resolving knowledge database 214, the conflict resolving device 203 performs simulation with the simulation device 201. Prioritize the competition according to the process status. The conflict resolution device 203 can be configured by using a simple dispatching rule or the like.

The plan display device 202 displays the result of simulation performed by the simulation device 201. Here, as the display method on the plan display device 202,
A Gantt chart or a loading order format can be used.

The initial condition setting device 211 sets the initial state of the manufacturing process model (Petri net model) created by the model creating unit 100 according to the actual manufacturing process status. Items that can be set as the initial state by the initial condition setting device 211 are as follows. 1) Manufacturing order (product to be made in the future) 2) Unprocessed work-in-progress (work-in-process that has not yet been started) 3) Buffer work-in-process (work-in-process remaining in the buffer) 4) In-machine work-in-process ( Work in progress being processed in the facility)

The performance collecting device 212 is a device for collecting the performance of work-in-process products in the manufacturing process. Here, the performance collection device 212 is a PLC attached to the production facility 213.
The FA-LAN is used to collect the results of work-in-progress from a POP (Point Of Production) system using a (programmable logic controller) or PLC.
Next, a specific production system configured by using the production planning apparatus according to the present invention will be described.

FIG. 7 shows an example of a concrete production system constructed by using the production planning apparatus according to the present invention.

This production system has three production equipments (equipment 1) PR1, (equipment 2) PR2, (equipment 3) PR3, and each production equipment PR1, PR2, PR3 has a buffer (buffer). 1) BU1, (buffer 2)
BU2, (buffer 3) BU3 and facility management programmable logic controller (facility management PLC) PLC
1, PLC2, PLC3 are provided.

In FIG. 7, the production planning apparatus according to the present invention is realized by a computer PC, and equipment management programmable logic controllers PLC1, P1 for the computer PC and each production equipment PR1, PR2, PR3.
The factory automation local area network FA-LAN is connected to LC2 and PLC3.

Further, in this computer PC, setup change information storage file F1 for storing setup change information of each production facility, model information storage file F2 for storing production process model information, conflict resolution for conflict resolution processing. A conflict resolution knowledge file F3 for storing knowledge is provided.

This production system includes three production facilities PR.
A plurality of products are manufactured by using 1, PR2 and PR3.
Here, it is assumed that the orders for the three production facilities PR1, PR2, and PR3 come irregularly, the production plan needs to be rebuilt each time, and the production facilities are frequently changed.

FIG. 8 functionally shows the internal structure of the computer PC shown in FIG.
C is composed of a main body PCB and a display CRT, and the main body PCB includes a model input device 10 and a model generation device 2
0, simulation device 30, conflict resolution device 40, simulation result sending device 50, initial condition setting device 60,
The performance collection device 70 is provided, and the display unit CRT is provided with the display device W1 and the plan display device W2. In addition, the model input device 10, the model generation device 20,
The basic operation of the simulation device 30, the conflict resolution device 40, the initial condition setting device 60, and the performance collection device 70 is shown in FIG.
The model input device 101 and the model generation device 10 shown in FIG.
3, simulation device 201, conflict resolution device 203,
It is the same as the initial condition setting device 211 and the performance collection device 212. The manufacturing order file F4 stores the manufacturing order. In addition, the simulation result sending device 50 outputs the simulation result of the simulation device 30 to the plan display device W2 of the display unit CRT.

Next, the process of model generation in this embodiment will be described with reference to FIGS. 9 to 11. 9 to 11 show the relationship between the screen actually displayed on the plan display device W2 of the display unit CRT and the model image on the memory.

When this system is activated, first, the parts box 501 shown in FIG. 9 is displayed on the display CRT. The user uses the mouse of the model input device 10 to select “equipment” or “buffer” from the component box 501.
Or select “Product”. Then, the selected component is placed on the display device W1 of the display unit CRT.

Here, when the selected part is "equipment", the equipment registration window 503 is opened, and the equipment number, equipment capacity, and setup change table number are input using this equipment registration window 503.

When the selected component is the "buffer", the buffer registration window 504 is opened and the buffer number and the buffer capacity are input using this buffer registration window 504.

When the selected part is "product", the product registration window 502 is opened, and the product number and the product name are input using the product registration window 504. Here, the arrangement of the display unit CRT on the display device W1 is not limited, and the display unit CRT can be arranged so as to correspond to the physical arrangement of the actual process.

Then, in accordance with the "equipment", "buffer", and "product" arranged on the display device W1 of the display unit CRT, a storage area having a data structure corresponding to each unit is secured in the memory.

This operation is repeated until the necessary equipment is defined on the display device W of the display unit CRT.

Next, as shown in FIG. 10, for each product,
Click the "equipment" and "buffer" that pass through with the mouse. As a result, a line connecting the “input product”, the “equipment”, the “buffer”, and the “output product” is displayed on the display device W of the display unit CRT in the order of clicking. However, the starting point is always set to "input product" and the ending point is set to "output product".

When the user clicks on "equipment", the work time setting window 505 is opened, and the work number and work time are input using this work time setting window 505. Here, the used equipment is automatically displayed corresponding to the click “equipment”, and the setting “equipment” can be confirmed by this.

Further, a storage area of a data structure corresponding to the work unit is secured on the memory.

Then, the data structure corresponding to the connection unit is secured in the memory, and the previous work unit and the work unit are connected. Here, when there is no previous work unit, it is connected to the input product unit.

When the user clicks on the "buffer", the data structure of the work performed by the "equipment" before and after the corresponding "buffer" and the data structure of the buffer are connected.

When the user clicks on the "output product", as shown in FIG. 11, the data structure of the work unit before the "output product" and the data structure of the output product are connected by the connection unit. .

The above operation is repeated from the "input product" to the "output product". Then, this operation is performed for all products.

The model thus created is stored in the model information storage file F2 in a format corresponding to the data structure. In this way, by storing the created model in the model information storage file F2 in a format corresponding to the data structure, by reading this model information storage file F2, it is possible to create a plan without inputting the model again. .

When modifying the created model,
Click the target equipment and correct each value in each registration window. When the number of facilities is increased or decreased, the facility icon is added or deleted.

With such a configuration, it is possible to create a model corresponding to the physical arrangement of the equipment on the display CRT, so that 1) the model can be easily created. 2) Correspondence between the model and the actual process. It is easy to correct the model by changing the equipment. 3) It is possible to expect effects such as no need for knowledge about Petri nets when creating the model, and the ignition duration can be any transition (N- 4) Transition with a fixed ignition duration (1-TR) because a unit with TR) is used.
It is possible to greatly reduce the required memory capacity compared to the case where 5) is used. 5) It is expected to have the effect that arbitrary setup change time and work time can be set.

Next, the performance collecting operation and the initial condition setting operation in this embodiment will be described.

As shown in FIG. 12, in this embodiment, each programmable logic controller PLC1, PLC2, PLC of each production facility PR1, PR2, PR3 is
3 manages and controls each production facility PR1, PR2, PR3, and the remaining time of the in-process work in process and each buffer BU
It is possible to obtain the number of work-in-process items in 1, BU2, and BU3, respectively.

Therefore, first, each production facility PR1, PR
2, PR3 programmable logic controllers P
LC1, PLC2, PLC3 or a programmable logic controller PLC1, PLC2, PLC3 (not shown) attached to the POP (Point Of Production) terminal, from each production equipment PR1, PR2, PR3, the type of work in process, remaining work time and each Buffer BU1, B
Acquire the type and number of work-in-progress items in U2 and BU3.

Each programmable logic controller PLC1, PLC2, PLC3 or each programmable logic controller PLC1, PLC2, PL
The POP terminal attached to C3 collects the in-process product information collected via the network FA-LAN to the computer PC.
Send to.

Initial condition setting device 6 in computer PC
0 receives this work-in-progress information and sets the initial conditions of the model based on this work-in-progress information.

This initial setting is performed as follows when there are work-in-process products in the buffer. That is, when there is a work-in-process in the buffer, first, the number of tokens in the data structure of the corresponding buffer capacity is reduced by the number of work-in-process in the buffer. Specifically, as shown in the “image on memory” in FIG. 12, the token of the place PL17 is decremented by 1 corresponding to the capacity of the buffer BU1.

Next, the number of tokens in the data structure of the place (PL) of the connection unit corresponding to the buffer of the relevant product is increased. Specifically, as shown in the "image on the memory" of FIG. 12, the tokens of the place PL6 are added by the number of in-process ones corresponding to the capacity of the buffer BU1.

When there is a work-in-progress (unstarted work) in the equipment buffer, the number of tokens in the data structure of the input unit of the corresponding product is increased by the number of work-in-process.

If there is a work-in-progress in the equipment, the token of the corresponding "equipment" is pulled out, and the variable time transition (N-TR) of the work unit of the "work" performed in the corresponding equipment is fired. Set duration to remaining work. Specifically, as shown in the "image on the memory" of FIG. 12, the token is removed from the place PL18 and the firing duration of the variable time transition TR8 is set to 5.

If there is a facility that is stopped due to a failure or the like, the token is deleted from the data structure of the "facility", and this "facility" cannot be used for simulation.

When the manufacturing order file F4 has a manufacturing order, the token of the product number corresponding to this manufacturing order is added to the token number of the place (PL) of the input unit of each product.

With this structure, the following can be achieved. That is, 1) The initial condition of the simulator in any state can be realized. 2) It is possible to set initial conditions that reflect the state of the manufacturing process. 3) Immediate rescheduling is possible in response to the addition of manufacturing orders such as diving. 4) The state of equipment can be reflected in the model.

Next, the simulation operation, conflict resolution operation, and planned output operation in this embodiment will be described.

The simulation device 30 shown in FIG.
The simulation is executed under the initial condition set by the initial condition setting device 60. In addition, the conflict resolution apparatus 40 shown in FIG. 8 determines the priority order of the competition when the competition occurs during the simulation by the simulation apparatus 30.

First, the time of the simulation device 30 is set to 0.
Set to.

Next, a transition (0-T
List R).

Then, a transition (0-
This transition (0-
If TR) fires, check if there is another transition (0-TR) that cannot be fired.

If there is no transition (0-TR) that cannot be fired, the transition (0-TR) is fired. Then, if this transition (0-TR) that has fired is the transition (0-TR) that is the start of the work of the work unit, the non-ignition attribute is attached to this transition (0-TR). Also, if the transition (0-TR) that fired is the transition (0-TR) of the input work unit,
This transition (0-TR) is given a non-ignition attribute of 1 unit time. In addition, the transition (0-TR) that fired is the transition (0-T) at the end of work.
If R), transition of work start (0-TR)
Remove the non-ignitable attribute of. Then, the firing time of each fired transition (0-TR) is recorded.

If there is a transition (0-TR) that makes it impossible to ignite, it is recognized that a conflict has occurred, and the product number, work number, and conflict of the transition (0-TR) that makes it impossible to ignite. The existing equipment name or buffer name is sent to the conflict resolution device 40 shown in FIG.

The conflict resolution device 40 refers to the conflict resolution knowledge in the conflict resolution knowledge file F3 to prioritize this conflict. Then, the simulation device 30 includes the transition (0-T) including the "work" having the highest priority.
R) is ignited, and the transition (0-T
If R) is the transition (0-TR) that is the start of the work of the work unit, this transition (0-T)
R) is given the non-ignitable attribute. If the fired transition (0-TR) is the transition (0-TR) of the input work unit, a non-ignition attribute of 1 unit time is added to the transition (0-TR).
If the fired transition (0-TR) is the work end transition (0-TR), the non-fireable attribute of the work start transition (0-TR) is released. And each fired transition (0-
(TR) record the time of ignition.

In addition, in the conflict resolution device 40, when the conflict resolution knowledge of the conflict resolution knowledge file F3 is referred to and it is determined that the current state is not suitable for firing, the transition (0-TR) cannot fire for only one unit time. Add attributes.

The above operation is repeated until there are no transitions (0-TR) that can be fired. Then, when there are no transitions (0-TR) that can be ignited, transitions (0-TR) where the firing duration is 0
The ignition continues.

Next, a transition (N-T) that can be fired among transitions (N-TR) whose firing duration is N.
List R).

Here, a transition (0-
Transition that can be ignited without (TR) (N-T
If there is no R), the simulation ends.

A transition (N-T
R), and this transition (N-T
If (R) is a transition (N-TR) indicating a setup change, the product number is obtained by performing the previous work from the data of the "equipment" being used, and the setup change information storage file F1 is based on this product number. The stored setup change information is searched to obtain the setup change time, and this transition (N
-TR) set the ignition duration time to the above setup change time and ignite. Then, the ignition time is recorded.

In addition, a transition (N-T
If R) is a transition (N-TR) indicating an actual work, the ignition duration time of the transition (N-TR) is set to the working time of the actual work to ignite. And
Record the firing time.

The above operation is repeated until there are no transitions (N-TR) that can be fired.

Next, the transition (N-
(TR) Ignition duration is reduced by 1 and simulation device 3
Advance a clock of 0 by 1.

Then, the non-ignition attribute having only one unit time transition (0-TR) is released.

The above operation is repeated until all the simulations are completed.

The simulation result sending device 50 shown in FIG. 8 arranges the firing times of transition (0-TR) and transition (N-TR) on the time axis after the completion of the simulation by the simulation device 30. Output as a Gantt chart.

The conflict resolution processing in the conflict resolution device 40 is executed based on the following conflict resolution knowledge. IF total delivery time margin = small THEN in order of smallest work time IF total delivery time margin = large THEN first-come-first-served basis IF total delivery time margin = small THEN minimum changeover time priority

Also, by giving the transition (0-TR) the non-firing attribute, the following can be achieved. 1) It is possible to prevent duplication check of ignitable transitions (0-TR) that are ignited according to the self-ignition rule and improve the simulation speed. 2) By suppressing ignition under certain conditions, a more optimal plan can be output in some cases.

The effect of giving the transition (0-TR) the non-ignition attribute will be further described with reference to FIG. In the case shown in FIG. 13, the transition (0-T
R) TR2 cannot reignite until the setup change time + actual work time elapses. However, if the transition (0-TR) TR2 is subject to the spontaneous firing condition, an ignition check of the transition (0-TR) TR2, that is, the transition (0-TR) is performed.
It will be repeatedly checked whether or not there is a token in the place (PL) before TR2. Therefore, by giving the transition (0-TR) TR2 the non-firing attribute, it is possible to move to the check of other transitions without checking all the input places (PL), thereby reducing the simulation time. It can be shortened.

By providing the conflict resolution device 40, the following can be achieved. 1) The simulation result can be used as a plan. 2) Ignition can be stopped under certain conditions.

[0125]

As described above, according to the present invention, 1) The symbol (icon expression) of the manufacturing process is input by the input means. 2) Work corresponding to the work carried out at each facility, consisting of a transition (N-TR) that can set the ignition duration arbitrarily and a transition (0-TR) that has the attribute of being unable to fire. Use a unit. 3) A model generation means is provided for connecting the units of the Petri net representation according to the input symbols. 4) A performance collecting means for collecting performances from the actual manufacturing process is provided. 5) An initial condition setting means for setting initial conditions in the Petri net representation of the manufacturing process based on the information from the performance collection system is provided. 6) If conflict occurs during the execution of the simulation, a conflict resolving means for eliminating the conflict is provided. Since it is configured as described above, the following effects are achieved.

1) A petri net model of a manufacturing process can be obtained without programming simply by inputting a symbol of the manufacturing process with an input device (mouse) and designating which facility each product passes through with the input device (mouse). Can be created, and the model seen on the display device can be easily associated with the actual process, so that the model can be created and modified easily, and no knowledge of the Petri net is required.

2) The work unit using the transition (N-TR), in which the ignition time can be arbitrarily set, can: a) make a plan considering the setup change time. b) Any work-in-progress state can be realized. c) The required memory can be reduced and the required memory capacity can be easily estimated.

3) The work unit using the transition (0-TR) having the non-ignition impossible attribute causes the non-ignition transition (0-T) caused by the spontaneous firing rule.
R) duplication check can be avoided and the simulation can be speeded up. Also, the start of arbitrary work can be delayed.

4) The status of each buffer and the remaining work time in the equipment can be obtained from the performance collection device (POP), and can be automatically input to the Petri net model without performing complicated work. Initial settings can be made in real time, and dynamic scheduling and rescheduling can be supported.

5) By setting the unusable equipment in the Petri net based on the equipment failure information from the performance collection device, it is possible to carry out the scheduling reflecting the performance.

6) It can be used as a simulation result by providing a conflict resolution means when a conflict occurs.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic system configuration of a production planning apparatus according to the present invention.

FIG. 2 is a diagram showing the basic elements of a Petri net used in this embodiment.

FIG. 3 is a diagram showing a specific configuration of each unit of this embodiment configured by combining the basic elements of the Petri net shown in FIG.

FIG. 4 is a diagram showing a transition ignition condition part 1 used in this embodiment.

FIG. 5 is a diagram showing a second ignition condition of a transition used in this example.

FIG. 6 is a diagram showing an operation of variable time transition (N-TR).

FIG. 7 is a system configuration diagram showing an embodiment of a specific production system configured by using the production planning apparatus according to the present invention.

8 is a block diagram functionally showing an internal configuration of the computer PC shown in FIG.

FIG. 9 is a diagram illustrating a process of model generation in this embodiment.

FIG. 10 is a diagram for explaining the process of model generation in this embodiment.

FIG. 11 is a diagram illustrating a process of model generation in this embodiment.

FIG. 12 is a system configuration diagram for explaining a performance collection operation and an initial condition setting operation in this embodiment.

FIG. 13 is a diagram for explaining an effect obtained by giving a transition (0-TR) a non-firing attribute.

[Explanation of symbols]

 100 model creation unit 101 model input device 102 display device 103 model generation device 200 simulation unit 201 simulation device 202 plan display device 203 conflict resolution device 111 setup change information storage device 112 model information storage device 214 conflict resolution knowledge database

Claims (21)

[Claims] 1. In a production planning apparatus for creating a production plan by executing a simulation using a Petri net model, if there is a transition in which the firings in the Petri net model conflict due to the simulation, A production planning apparatus comprising: a conflict resolution means for eliminating the conflict based on the stored conflict resolution knowledge. 2. The production planning apparatus according to claim 1, wherein the conflict resolution knowledge gives priority to firing a transition corresponding to a manufacturing process having a short working time when the production delivery date is short. 3. The production planning apparatus according to claim 1, wherein the conflict resolution knowledge prioritizes firing of a transition corresponding to a manufacturing process that arrives earlier when a production delivery date is long. 4. A production planning apparatus for creating a production plan by executing a simulation using a Petri net model, and actual result information collecting means for collecting actual result information from a production facility targeted by the Petri net model, A production planning apparatus comprising: initial condition setting means for setting an initial condition of the simulation of the Petri net model in correspondence with the performance information collected by the performance information collecting means. 5. The work-in-progress information indicating the type of work-in-progress in the production facility and the remaining work time in the production facility.
The production planning device described. 6. The production planning apparatus according to claim 4, wherein the record information is work-in-progress information indicating a type and the number of work-in-progress in a buffer at a preceding stage of the production facility. 7. The initial condition setting means removes the talk from the place of the work unit corresponding to the work of the Petri net model, and sets the transition firing duration of the work unit to the remaining work time. The production planning apparatus according to claim 5, which is characterized in that. 8. The initial condition setting means reduces tokens from a place of a buffer unit corresponding to the buffer of the Petri net model, and adds the token to a place of a connection unit corresponding to the buffer. The production planning apparatus according to claim 6. 9. The initial condition setting means deletes a token from a place of an equipment unit corresponding to the production equipment of the Petri net model when there is a production equipment that is stopped, and simulates the production equipment. The production planning apparatus according to claim 4, wherein the production planning apparatus is prohibited. 10. The initial condition setting means, when a manufacturing order is added, adds a token corresponding to the added order to the place of the input product unit of the Petri net model. The production planning device described. 11. A production planning apparatus for creating a production plan by executing a simulation using a Petri net model, comprising: a simulation apparatus for executing the simulation, wherein the simulation apparatus comprises the Petri net. Extraction means for extracting ignitable transitions from the net model, competition determination means for checking whether there is a transition that cannot be ignited due to ignition of the ignitable transitions extracted by the extraction means, and the competition determination means When it is determined that there is a transition that makes it impossible to fire, it is determined that a conflict has occurred, and a conflict resolution requesting unit that requests the conflict resolution device to resolve the conflict, and receives the conflict resolution information from the conflict resolution device to resolve the conflict. And a means for canceling the production plan. 12. A production planning apparatus for creating a production plan by executing a simulation using a Petri net model, comprising: a simulation apparatus for executing the simulation, wherein the simulation apparatus comprises the Petri net. Extraction means for extracting ignitable transitions from the net model, and ignite the ignitable transitions extracted by the extraction means. If the ignited transition is a transition that is the start of a work unit, one unit time is ignited. A non-firing attribute adding means for giving a non-firing attribute, a non-firing attribute releasing means for releasing the non-firing attribute if the transition that can be fired extracted by the extracting means corresponds to the end of the work unit, and the extracting means Ignitable transitions extracted in Production planning apparatus characterized by comprising a firing time recording means for recording the ignition time of the emission, the. 13. A production planning apparatus for creating a production plan by executing a simulation using a Petri net model, comprising: a simulation apparatus for executing the simulation, and the Petri net model: The simulation device comprises a variable time transition whose duration can be set to an arbitrary value, and the simulation device extracts the variable time transition from the Petri net model, and the variable time transition extracted by the extracting means. A production planning apparatus, comprising: an ignition duration setting means for setting an ignition duration and igniting; and an ignition time recording means for recording the ignition time of the transition fired by the ignition duration setting means. . 14. In a production planning apparatus for creating a production plan by executing a simulation using a Petri net model, after the completion of the simulation, the production plan is arranged with a firing time of each transition on a time axis. A production planning apparatus, comprising: a plan output unit for outputting as a chart. 15. A production planning apparatus for producing a production plan by executing a simulation using a Petri net model, comprising: display means; and model generation means for producing the Petri net model. The generation means includes storage means for storing the generated model, input means for inputting manufacturing process symbols, means for arranging the manufacturing process symbols input by the input means on the screen of the display means, and By sequentially selecting symbols for each manufacturing process arranged on the screen, a storage area for storing a data structure corresponding to each unit of the Petri net model represented by the selected manufacturing process symbol is provided on the storage means. And a means for inputting data of each manufacturing process in the storage area secured on the storage means, Production planning apparatus characterized by comprising a means for generating the Petri net model by connecting each unit corresponding to each symbol that is selected on the surface. 16. The production planning apparatus according to claim 14, wherein the symbol is composed of a symbol indicating input product, output product, facility, and buffer. 17. The means arranged on the screen has a symbol indicating the input product as a starting point and a symbol indicating the output product as an end point, and between the symbol indicating the input product and the symbol indicating the output product. 17. The production planning apparatus according to claim 16, wherein a symbol indicating the facility and a symbol indicating the buffer are arranged in the. 18. Corresponding to the selection of a symbol on the screen, starting from the symbol indicating the input product, passing through the symbol indicating the facility and the symbol indicating the buffer to the symbol indicating the output product at the end point. 18. The production planning apparatus according to claim 17, wherein the line connecting the lines is displayed on the screen. 19. The production planning system according to claim 14, wherein each unit is configured by combining basic elements of a Petri net. 20. The production planning apparatus according to claim 14, wherein each of the units includes an input product unit, an output product unit, a work unit, a buffer unit, and a connection unit. 21. The means for generating the Petri net model has the input product unit as a starting point and the output product unit as an end point, and the working unit between the input product unit and the output product unit, 23. The production planning apparatus according to claim 22, wherein the buffer unit and the connection unit are connected in combination.