JP2855836B2 - Petri net diagram making device - Google Patents

Description

The present invention relates to an apparatus for creating a Petri net diagram used for simulation and evaluation of a production system, etc.
In particular, the present invention relates to an apparatus for creating a Petri net diagram on a display by interactively operating a workstation or a personal computer.

[Conventional technology]

A Petri net is known as a model of a system composed of simultaneous elements such as a production system.

The Petri net is a directed graph composed of two types of nodes, place and transition, and an arc connecting these nodes. A place corresponds to a condition for an operation to occur in the system, and a transition corresponds to the operation. Then, the processing of the system proceeds in the direction indicated by the arc.

It is conventionally known to execute a simulation of a system modeled by this Petri net on a computer (for example, the Operations Research Society of Japan, Abstracts of 1988 Fall Meeting,
218-219, JP-A-63-317805, etc.).

At the time of this simulation, it is necessary to create a Petri net diagram on a computer in advance, but it is necessary that a user can easily make this change or change after creation.

An interactive system that enhances the operability for the user is an interactive system. This interactive system advances data processing through a dialog between the user and the system. , And the system repeats the process of reflecting the result in accordance with the instruction on the display screen. In this case, it is important how much the system can display in a form that is easy for the user to understand.

[Problems to be solved by the invention]

In the conventional Petri net diagram creation device, since a relatively small Petri net diagram is targeted, it is possible to simultaneously display the entire Petri net diagram on a display screen. However, as the scale of the system to be modeled increases, the Petri net diagram also becomes more complicated and larger, but the size of the display screen is limited, so the entire graph must be displayed simultaneously. However, it is necessary to perform scroll display or split display, and editing work is difficult. Further, if the Petri net graph is reduced, the entire Petri net graph can be displayed. However, the graph becomes difficult to see and the editing operation is also difficult.

Also, since the data of all nodes is centrally managed, every time the user performs some processing, information such as nodes that are not displayed on the screen is also processed. there were.

The present invention facilitates the creation of a large-scale Petri net diagram by dividing the entire Petri net hierarchically and uniformly managing the divided Petri nets, in order to improve the disadvantages of the prior art. The purpose is to make it possible.

[Means for solving the problem]

According to the present invention, in order to achieve the above object, in a Petri net diagram creating apparatus comprising means for generating a Petri net diagram and means for displaying the generated Petri net diagram, means for designating an area in the Petri net diagram Means for abstracting the Petri net diagram in the designated area to generate a higher Petri net diagram, means for generating the substance of the Petri net diagram in the designated region as a lower Petri net diagram, Means for generating a connection node that defines a connection relationship between an upper Petri net diagram and a lower Petri net diagram;
Means for unifying and managing Petri net diagrams hierarchized based on the connection nodes.

[Action]

 The operation of the present invention will be specifically described with reference to examples.

FIG. 1 is a block diagram showing a schematic configuration of the present invention. In this figure, a control unit 101 performs a process according to a command from a command input unit 102 such as a keyboard and a mouse, for example, generates a Petri net diagram, displays the result on a Petri net diagram display unit 104, and displays the result on the Petri net diagram. Write to the net diagram storage unit 103. Further, the control unit 101 receives a request such as a change to the Petri net diagram already displayed on the Petri net diagram display unit 104 from the command input unit 102, and after processing the request, the screen is displayed by the Petri net diagram display unit 104. Displayed above, and the changes are stored in the Petri net diagram storage unit 104.

When a request for layering Petri net diagrams is issued from the command input unit 102, the control unit 101 performs processing such as preparation for creating a new Petri net diagram according to the request, and performs processing between the layered Petri nets. An abstracted node representing a connection relationship and an abstracted node representing a hierarchical Petri net are added to each hierarchical Petri net, and the display image and the Petri net on the Petri net diagram display unit 104 are added. The content stored in the net diagram storage unit 103 is updated.

〔Example〕

 Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 2 shows the overall configuration of a workstation for implementing the present invention. Workstation 20
1, main storage device 202, display device 203 such as a bitmap display, data input device 204 such as a keyboard,
It comprises a pointing device 205 such as a mouse, an auxiliary storage device 206 such as a magnetic disk, and the like.

Here, the correspondence between the configuration shown in FIG. 1 and the embodiment of the present invention is shown. The control unit 101 is a control device 201, and the command input unit 102 is a data input device 204 and a pointing device 205.
In addition, the Petri net diagram storage unit 103 is in the main storage device 202 and the auxiliary storage device 206, and the Petri net diagram display unit 104 is in the display device 20.
3 respectively.

FIG. 3 shows a control flow in this embodiment. In this figure, a request from a user is transmitted to a control device 201 via a data input device 204 or a pointing device 205, and after performing a process according to the request, for example, creating a Petri net diagram, the result is displayed. Display device
The control unit 201 performs a process corresponding to the operation of the pointing device 205 by providing feedback to the display device 203 by displaying it on the 203 or notifying the user, and the user issues a new request while watching this. The data representing the Petri net diagram is stored in the main storage device 202 and, if necessary, the auxiliary storage device 206.
Is accumulated in The processing in the control device 201 includes new creation and editing of a Petri net diagram, saving to a file (writing to the auxiliary storage device 206), reading from a file (reading from the auxiliary storage device 206), and the like. As will be described later, when the data input device 204 or the pointing device 205 instructs the layering of the Petri net diagram, the management of the Petri net diagram is performed according to this.

Now, a procedure in which a user creates a Petri net diagram as a source of layering as shown in FIG. 4, for example, will be described with reference to the flowchart of FIG.

First, the user opens a Petri net diagram creation window 702 on the display screen 701 of the display device 203 as shown in FIG. At the start of the Petri net diagram creation work, only the Petri net management window 703 is displayed on the display screen 701 (step S101). For example, the menu “New” in the Petri net management window 703 is selected. (Step S102) opens a Petri net diagram creation window 702 (Step S103). Further, when a pointing device 205, for example, a menu button of a mouse is pressed in a state where nothing is displayed on the window 702, “place”, “transition”,
A Petri net menu 705 having items such as "layering", "load", and "save" is displayed (step S10).
Four). “Place” and “transition” are for creating nodes of the Petri net diagram, and “layering” is for instructing the layering of the Petri net diagram as described later. “Load” is an instruction to read an existing Petri net from a file, and “Save” is an instruction to save a Petri net to a file.

In the example of FIG. 6, a Petri net diagram is already drawn in the window 702, and this diagram is created by selecting a necessary function from the Petri net menu 705.

For example, when it is desired to newly create places 401, 402, 403, 404 as shown in the Petri net diagram of FIG. (Step S10
6). The generated place moves on the window 702 in accordance with the movement of the pointing device 205, that is, the cursor that moves in accordance with the instruction of the mouse, and is fixed at the position where the mouse button is pressed (step S107). Data representing attributes such as the position and shape of the place is generated as place data (step S108) and stored in the main storage device 202 (step S109). The tokens 415 and 416 placed in the place can be set by the data input device 204.

Similarly, the transitions 405 and 406 are generated by mouse operation, the position is specified, and transition data indicating the attribute of the transition is stored in the main storage device 202.

In addition, between places and transitions,
Arcs 407 to 414 between the nodes are also generated by mouse operation. That is, when an arc is to be formed from a certain place to a certain transition, the cursor is first moved to the place, and here, the mouse button is kept pressed. Then, the cursor changes from an arrow to a cross, and a straight line connecting the center of the place and the center of the cursor is displayed. Next, when the cursor is moved over the transition and the mouse button is released, the arc is determined, and the regular arc is displayed on the screen. At this time, if the mouse button is pressed other than during the transition, the mouse button is invalidated, the state is returned to the original state, and the mode is changed to an input acceptance mode. Attributes such as the position and shape of the arc are defined by arc data described later. Once the arc is drawn, the locus of the arc can be freely edited by operating the mouse and operating a menu having “edit” and “delete” items displayed by pressing a menu button on the arc line. The above operation is repeated until the creation of the desired Petri net is completed (step S110). These processes can be realized using a window system widely used in a workstation or the like.

Here, the structure of Petri net data for representing a Petri net diagram will be described. As shown in Table 1, the Petri net data is given in each Petri net diagram by a variable name indicating the name of the Petri net and an array for holding transitions, places, connection nodes, representative nodes, and arcs. Each variable transitions, plac
It consists of es, connectNodes, repNodes and arcs. The meaning of the connection node and its variable connectNodes and the meaning of the representative node and its variable repNodes will be described later.

Also, the transition data and place data are
As shown in Tables 2 and 3, variables inputArcs and outputArcs given in a one-dimensional array, respective variables position and icon for representing a position and a shape, and identifiers different from each other are provided. Arcs that have an input relationship when viewed from the node are inputArcs, and arcs that have an output relationship are o
A pointer to each arc is stored in utputArcs. The information on where to display the node in the window has a variable position, and the icon to be displayed has an icon.
The place data has a variable tokenCount indicating the number of tokens placed in the place.

Also, as shown in Table 4, the arc data has pointers to the start node and the end node in variables called startNode and endNode, respectively. Also,
In order to display the arc as a curve, the intermediate coordinate values are put in a variable given by an array called collectionOfPoints, and when displaying the arc, these are sequentially connected with a straight line.

In the present embodiment, as will be described later, a designated portion of a Petri net diagram is abstracted by a symbol called a representative node, and the substance of the abstracted portion is created as another hierarchical Petri net diagram. . The connection relationship between the hierarchical Petri net diagrams is defined by a newly introduced node called a connection node.

The representative node data defines an abstracted symbol when the Petri net diagram is hierarchized, that is, the attribute of the representative node. As shown in Table 5, the representative node data includes the hierarchized upper and lower layers. The variable connectP representing the connection node for defining the connection state of the lower Petri net diagram
oints, variables position and icon to represent the position and picture of the abstracted symbol, and a variable petriNet to hold the name of the lower-level Petri net that is the entity of that node.
There are variables such as id. The variable connectPoints is given as a one-dimensional array, in which connection nodes having the same ids as the connection nodes of the Petri net they represent are placed.

Further, as shown in Table 6, the connection node data has the same data as the transition data.

In the present embodiment, the connection relationship between the representative node and the Petri net that is to be the entity is realized by the equivalence of the id of this connection node.

Next, the process of hierarchizing the Petri net diagram shown in FIG. 4 will be described with reference to the flowchart in FIG.

As shown in FIG. 6, when the Petri net diagram creation window 702 and the Petri net menu 705 are displayed, the menu 7 is moved by the menu selection cursor 704.
When "hierarchy" in 05 is instructed, the system first generates a new representative node (step S201),
Area for new Petri net data in main storage 20
2 (step S202). Then, the shape of the cursor is changed to a hook-shaped frame designation start cursor 80 as shown in FIG.
Change to 1 to set the mode to specify the upper left corner of the area to be specified. When the start point is determined, press the mouse button, this time the cursor shape changes to the frame specification end cursor
The mode changes like 802, and the mode is for specifying the lower right corner of the area. Next, when the mouse button is pressed, the area (indicated by the dotted rectangle) is determined, and the area designation is completed (step S203).

The system checks which nodes are included in this area from the coordinate information included in the position data position of each node data, and deletes the ones in the area from the Petri net data and newly generated Petri nets. Move to net data (step S204). At the same time, the arcs connected to those nodes are
And outputArcs, and among those arcs, arcs that do not extend outside the region are also transferred to new Petri net data (step S205). That is, in the example of the Petri net shown in FIG. 4, the four nodes of the places 402 and 404 and the transitions 405 and 406 are identified by the designation frame 417 indicating the outer periphery of the designated area. Six arcs 408, 409, 411, 412, 413 and 414 are taken out as arcs inside the area, and these arcs are deleted from the original Petri net and substituted into the corresponding variables of newly generated Petri net data.

Next, the arcs extending over the inside and outside of the designated frame 417 are examined, and arcs 407 and 410 are found in FIG. The arcs found here are temporarily erased from the display screen, and the nodes inside the designated box 417 of those arcs, that is, the nodes moved to the newly generated Petri net, arc 407 and 410, respectively. Arcs 603 and 604 of the copy (see FIG. 9) are added (step S20).
6). These copies all have the same information as the original except for the id. At this time, connection nodes 601 and 602 as shown in FIG. 9 are generated and connected to one end of the arc (step S207). The data of the connection nodes 502 and 503 (see FIG. 10) of the copy of the connection nodes 601 and 602 generated here are added to the variable connectNodes of the representative node data generated on the original Petri net (step S209). ).

In the representative node 501, the variable connetP of the variable node data
The connection node in the oints is represented by the connection nodes 502 and 503 in FIG.
And 603. That is, in the case of the present embodiment, the connection node 50 of the representative node in the upper Petri net diagram
Squares are used as 2 and 503, and triangles are used as connection nodes 601 and 603 in the lower Petri net diagram, so that identification can be easily performed. Note that even if the cursor is on the representative node 501 on the display screen 701, if the cursor is on the connection node 502 or 503, the connection node is recognized so that an arc can be individually set. Becomes possible.

By the above-described series of processes, the Petri net data (see Table 1) of the newly generated Petri net diagram is determined. However, if the variable name is not specified by the user,
The system sets it automatically.

On the other hand, in the original Petri net, the icon of the representative node is automatically created from the information of the connection nodes 502 and 503 of the newly generated representative node 501 (step S210), and based on this information, as shown in FIG. Then, the hierarchical Petri net diagram is displayed (step S211). The variable petriNet of the representative node contains the variable of the newly created Petri net.
The name is stored, so that it is possible to know which Petri net the representative node represents.

By selecting “open” from the representative node menu 902 with the menu selection cursor 901 as shown in FIG.
It is displayed as a window 1001 in FIG. 2 (step S21
2 to S214). The representative node menu 902 can be displayed by pressing a menu button on the figure. In addition to “open”, the representative node menu 902 includes “move”, “copy”, and “delete”. There is.

The above-described processing is performed by the control device 201, and how the entire Petri net is hierarchized is independent of the Petri net diagram, and the Petri net management as shown in FIG. The user is notified by the Petri net control chart displayed in the window 703. As described above, the first Petri net diagram is created by a new creation menu in this control chart. From this control chart, only one Petri net diagram can be created, and the Petri net diagram is the top level of the Petri net diagram that is expressed hierarchically. FIG. 14 shows a Petri net hierarchized into three layers 3 shows an example of the control chart. In the first layer there is a Petri net named "1", in the second layer there are two Petri nets named "2" and "3", and further in the Petri net. Below the net “2”, there is a third-layer Petri net named “4”. These names are the variables in each Petri net
The name itself. The hierarchical relationship is represented by a tree structure, and the leftmost one indicates that the topmost Petri net is.

The operation in which the Petri net control chart displays this hierarchical structure is as follows. The Petri net control chart has the Petri net generated there as a variable, and examines the variable repNodes of this Petri net to determine whether or not the Petri net has a hierarchical Petri net. If not, the Petri net is unhierarchical, but if present, the variable of the representative node in repNodes
Look at petriNet and find the entity of the Petri net. If the entity is not on the main storage device 202, the contents of the auxiliary storage device 206 are checked, and the variable repNodes of the Petri net is further checked there. Once all the representative nodes in all repNodes have been examined, work on the display starts. That is, the number of layers in the whole is checked, a tree is formed based on the hierarchical dependency, and the tree is automatically named and displayed on the display device 203.

In this Petri net control chart, the user moves the cursor to a node marked "4" in FIG. 14, and performs an operation of opening a window, such as quickly pressing a mouse button twice. The Petri net diagram can be displayed. Then, using the cursor 1002 on this lower Petri net diagram, operations such as creation and editing can be performed in the same manner as the original Petri net diagram.

Thus, by looking at the control chart of the entire Petri net, the overall configuration becomes extremely clear.

As a modified example of the embodiment, application to a colored petri net, an extended petri net considering the concept of time, and the like, an arc flow graph, and the like can be considered. Each of these is composed of a plurality of nodes and links connecting them.

Further, in the above embodiment, a function for managing the entire Petri net diagram is provided. However, this is decomposed for each Petri net diagram, and a Petri net diagram connected to the Petri net diagram is connected. If only the figures can be called, the same operation as in the above embodiment can be performed.

〔The invention's effect〕

As described above, according to the present invention, the Petri net diagram is displayed in a hierarchical manner. Therefore, even when the Petri net diagram becomes large and complicated, the user can glance at the display device. The whole can be displayed in a recognizable state, and creation and editing of Petri net diagrams can be easily performed. Further, since the number of elements to be displayed in the Petri net diagram divided into parts can be reduced, there is an effect that the possibility of overlooking the display content is reduced and the time for display can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of the present invention, FIG. 2 is a configuration diagram of a workstation for implementing the present invention, FIG. 3 is an explanatory diagram showing a control flow in the present embodiment, and FIG. FIG. 5 is an explanatory view showing an example of an unconverted Petri net diagram, and FIG.
FIG. 6 is a flowchart showing basic processing for creating a Petri net diagram, FIG. 6 is an explanatory diagram showing an example of a display screen when a basic Petri net diagram is created in this embodiment, and FIG. FIG. 8 is a flow chart showing the processing when the figure is hierarchized, FIG. 8 is an explanatory view showing an example of a display screen when an area is specified when the Petri net figure is hierarchized, and FIG. FIG. 10 is an explanatory diagram showing a lower Petri net diagram in the case of hierarchization, FIG. 10 is an explanatory diagram showing an upper Petri net diagram in a case where the Petri net diagram shown in FIG. 4 is hierarchized, and FIG. FIG. 12 is an explanatory view showing an example of a display screen on which a Petri net diagram is displayed, FIG. 12 is an explanatory view showing an example of a display screen on which an entity of a lower Petri net is displayed, and FIG.
FIG. 14 and FIG. 14 are explanatory diagrams of different examples showing a management diagram of a hierarchical Petri net. 101: control unit, 102: command input unit 103: Petri net diagram storage unit 104: Petri net diagram display unit 201: control device, 202: main storage device 203: display device, 204: data input device 205: pointing device 206: Auxiliary storage device, 401 to 404: Place 405, 406: Transition 407 to 414: Arc, 415, 416: Token 417: Designated frame, 510: Representative node 502, 503, 601, 602: Connection node 603, 604: Arc, 701: Display screen 702: Window for creating Petri net diagram 703: Petri net management window 704: Menu selection cursor 705: Petri net menu 801: Frame specification start cursor 802: Frame specification end cursor 901: Menu selection cursor 902: Representative node menu

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-120980 (JP, A) JP-A-1-109475 (JP, A) JP-A-62-256171 (JP, A) JP-A-62-256 239273 (JP, A) Yoshihiro Okada et al. "Visual Simulation System" Transactions of the IPSJ 40th National Convention (III) (March 14, 1990), 1357, 1358. "Tools for Network Analysis and Design Software Development" Proceedings of the 33rd Annual Conference of the Society of System Control and Information Engineers (May 17, 1989), pp. 349, 350 Kensuke Hasegawa "Application of Petri Nets to Production Systems" "Measurement and Control, Vol. 28, No. 9 (September 1989) pp. 775-783 Hisao Shiizuka, "Application of Petri Net to Simulation (IV), Operations. Research, Vol. 35, No. 2, February 1990, pp. 120-125.

Claims (1)

(57) [Claims] An apparatus for creating a Petri net diagram, comprising: means for generating a Petri net diagram; and means for displaying the generated Petri net diagram. Means for abstracting the Petri net diagram in the above as a higher Petri net diagram, means for generating the substance of the Petri net diagram in the designated area as the lower Petri net diagram, and Means for generating a connection node that defines a connection relationship with a lower-level Petri net diagram; and means for unifying and managing a hierarchical Petri net diagram based on the connection nodes are provided. Petri net diagram creation device.