JPH08187648A - Production line construction method and production line control system - Google Patents

Abstract

PURPOSE: To construct an optimum production line with no waste by determining combination of each production basic element of minimizing a cycle time, by using a virtual plant to simulate a process of goods production in a simulation means. CONSTITUTION: A virtual production plant means 2 has virtual operating system 22 of using a programmable cell unit model 21 of simulating an actual plant cell controlled by each plant cell unit controller part. In a cell unit model 21, a production plant is combined with a production basic element model, prepared from a specific viewpoint, and constructed so as to provide a structure and behavior equivalent to an actual plant. A control condition, obtained in a control condition indicating means 3 and a virtual plant means 2, is indicated in each plant cell unit controller part 1 through a communication bus BS. Of each production basic element of constituting the cell unit model 21, an equipment element, changing an internal condition, action mode and internal variables with the lapse of time, performs action in accordance with these changes.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is a method for constructing an optimum production line for efficiently producing a desired product while processing, transporting, and assembling raw material intake, and a method for constructing the optimal production line. Regarding the management system of the production line. More specifically, storage means for storing production basic elements simulating machines and equipment elements such as a transfer line, a processing line, an assembly line, and an inspection line that compose the production line, and a plurality of production basics read from this storage means. A virtual factory construction means for constructing a virtual production line (virtual factory) by combining elements and a simulation means for simulating product production using the constructed virtual factory are provided, and products can be efficiently produced. The present invention relates to a production line construction method capable of constructing an optimum production line. The present invention also relates to a production line management system capable of efficiently managing the production line constructed by this method.

[0002]

2. Description of the Related Art Conventionally, when constructing a new factory, machines and equipment are arranged according to the production process of the products produced there, but if the brand of the products produced is frequently changed, The production line also needs to be changed accordingly. At this time, what kind of machines and equipment should be used, in what order and combination they should be placed, and what value should be set for the management conditions of those machines and equipment should be determined from the conventional production line. I had to rely on the experience and knowledge of the operators and managers who knew well about it.

A distributed control system (DCS) is known as a control system for controlling and managing a product production line. An example of such a system is disclosed in, for example, Japanese Patent Laid-Open No. 59-16013. The DCS is composed of a plurality of control stations for distributed plant control, and a monitoring operation station that is connected to each control station via a communication bus and operates and monitors a process. Each control station performs control operation independently, and regular communication is performed between the control station and the monitoring operation station via the communication bus, and various data handled by the control station is sent to the monitoring operation station. It is configured so that the user can grasp it in real time.

As a result, a highly reliable production system is realized by distributing control functions, monitoring information and concentrating operations.

[0005]

The conventional method of constructing a production line based on the experience and knowledge of operators and managers or the can greatly depends on the experience and knowledge of individuals. Further, when the product brand is frequently changed, it is not possible to respond promptly, and there is no guarantee that an optimal production line will always be constructed.

On the other hand, in the conventional distributed system for controlling and managing the constructed production line or plant, when the scale of the plant to be controlled becomes large, a communication bus connecting each control station and the monitoring operation station. Since a large amount of data including process data is transmitted, a high-speed and highly reliable device is required, and the entire system becomes expensive. In addition, it is difficult to easily deal with a change in production brand and a rearrangement of lines in accordance with the change.

[0007] Here, an object of the present invention is to provide a production line construction method capable of constructing an optimum production line capable of efficiently producing a product quickly and economically. Further, it is another object of the present invention to provide a production line management system capable of flexibly responding to a change in production plan, a change in production brand, etc., and capable of efficiently managing production of products. .

[0008]

The present invention which achieves such an object stores the production basic elements simulating machines and equipment elements such as a transfer line, a processing line, an assembly line, and an inspection line which constitute the production line. And a virtual factory construction means for constructing a virtual production line (virtual factory) by combining a plurality of production basic elements read from this storage means, and a simulation of product production using the constructed virtual factory A first step of constructing a virtual factory by combining a plurality of production basic elements according to a flow of product production by the virtual factory construction means, and a simulation means using the virtual factory constructed by the first step. The second step of simulating the product production process and the cycle timer set for each production basic element. The first step and the second step are repeated so that the cycle time is minimized, and the third step for determining the combination of the respective production basic elements for which the cycle time is minimized and the steps determined by the third step are performed. And a fourth step of constructing an actual production line based on a combination of production basic elements.

Further, the present invention is provided with a plurality of independent distributed type plant cell unit controller sections, and a management device which is connected to each of these plant cell unit controller sections via a communication line to instruct a management condition. A storage unit for storing production basic elements simulating machines and equipment elements such as a transport line, a processing line, an assembly line, and an inspection line, which form a production line, in the management apparatus,
A virtual factory construction means for constructing a virtual production line (virtual factory) by combining a plurality of production basic elements read from this storage means, a simulation means for simulating product production using the constructed virtual factory, and a virtual The production line management system is provided with a management condition instruction means for downloading the management condition obtained at the factory to each plant cell unit controller section via the communication line.

[0010]

[Function] The virtual factory provided on the management device side has a large number of production basic elements (cell units), and these production basic elements are combined assuming a production line for producing a product intended. , Build a virtual factory that simulates a real plant. In this virtual factory, for example, a virtual panel for displaying a three-dimensional image and a simulation means can be provided, and the process in which a product is produced through each line can be verified on this panel. The production line is completed.

An actual production line is constructed in accordance with a combination of production basic elements that make up a virtual factory.
The management condition instructing means downloads the management condition obtained by the verification at the virtual factory to each plant cell unit controller section side which controls the actual production line through the communication line.

As a result, the plurality of plant cell unit controller sections individually control the production line such that the controller sections cooperate with each other.

[0013]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a diagram for explaining the production line construction method of the present invention, showing an example of a display screen of a computer. This screen includes a symbol display section W1 for displaying symbols that represent a production basic element 212 or the like that simulates a machine such as a transfer line, a processing line, an assembly line, an inspection line, or an equipment element that constitutes the production line, and the production of these. It has a line layout section W2 for designating a basic element and constructing it as a production line.

Each symbol indicating the production basic element 212 can define (set) data such as a cycle time and a manufacturing process number. Although not shown, software (program) and data relating to each of these symbols are stored in a storage means of a computer, and a specific production basic element is selected by using a keyboard, a mouse, or the like, thereby producing the production. Data about the basic elements are read out. The symbols of the selected production basic elements can be arranged at appropriate positions in the line layout section W2, and these are combined according to the flow of product production to construct a desired production line on the line layout section W2.

Here, the connection between the respective production basic elements is performed by a method well known in the art, such as a graphic editor, and the programs and data constituting the respective production basic elements are connected to each other, A cell unit model showing a virtual production line that simulates an actual production line is created. When a virtual factory is constructed in the line layout section W2 in this way, the simulation means simulates product production using the constructed virtual factory. In this simulation,
Information on the product brand to be produced is given to the virtual factory, and the process until the product is output from the virtual factory is verified. Then, if necessary, the layout of production basic elements can be changed or changed to another production basic element so that the cycle time set for each production basic element can be minimized. , Build an optimal production line.

When the optimum production line is determined on the line layout section W2, an actual production line is constructed in accordance with the determined combination of the production basic elements.
According to such a production line construction method, various situations for product production can be verified by simulation in the virtual factory constructed in the line layout section W2. Then, since the actual production line is constructed based on the result, it is possible to construct an optimal production line quickly and at low cost without waste.

FIG. 2 is a block diagram showing an example of a production line management system according to the present invention. In the figure, OF is a management device side, PLT is a plant or factory side, and these are connected by a generalized communication bus (communication line) BS. In addition, this communication bus BS
In addition to those configured by using a communication cable, those configured by a wireless line are included.
In each production line in the plant PLT, each production basic element is laid out by the method described with reference to FIG. 1, and in each production basic element, management parameters such as cycle time are set. And

On the factory side, 1 is a plurality of plant cell unit controller sections forming an independent distributed system. Based on the management conditions set therein, each of these controller units inputs various signals from the sensor SNR installed in the plant in its own range, and actuators such as valves, solenoid valves, and switches. It is configured to control the ACR. The controller units are connected to each other via a communication bus BS, and control information and the like required for production control are transmitted via the communication bus BS.

Here, the self-sustaining decentralized system does not have a centralized management function, and each element part constituting the system operates or acts autonomously, so that the entire system operates in a coordinated manner. It refers to the system that produces the target product, and a general-purpose computer can be used. As an article explaining the self-sustaining distributed system, for example,
"OHM" August 1994, pages 58-67.

On the management device side, 2 is a virtual manufacturing plant means, which is a virtual operating plant using a programmable cell unit model 21 simulating an actual plant cell controlled by each plant cell unit controller section. The system 22 includes a virtual panel 23, which is an output unit, and a memory unit 24 that stores various data. Here, the programmable cell unit model 21 is a virtual factory composed of a combination (collection) of the respective production basic elements constructed by the method described with reference to FIG.

Therefore, the programmable cell unit model 21 simulating an actual plant (production line) is
A production plant with a specific perspective, such as transport elements, processing elements,
Combining many production basic element models created from the viewpoint of assembly elements, verification elements, storage elements, manpower elements, etc.
It is constructed to have a structure and behavior equivalent to that of a real plant.

Reference numeral 3 is a management condition instruction means, which is a virtual factory means 2.
The management conditions obtained in (1) are instructed to each plant cell unit controller section 1 via the communication bus BS. FIG. 3 is a diagram showing an example of a screen displayed on the virtual panel 23 in the virtual factory means 2.
The images displayed here are automated warehouses, operators, automated guided vehicles (AGV), robots, conveyor units that combine straight lines and quarter arcs, and monorail guided vehicles (OH).
V), OHV rail that combines straight lines and quarter arcs,
Machining center, turntable, container box, cell controller, limit switch, pallet,
It consists of objects such as workpieces and communication networks. As described above, the virtual operating system 22 has a cell unit model (virtual factory) that is a combination of production basic elements according to the actual plant.

Among the production basic elements (objects) constituting the constructed cell unit model (virtual factory), the actively operating equipment elements are the internal states, operation modes, and internal variables of the active equipment elements over time. (The value of the internal register) changes, and the operation corresponding to these changes is performed. Also, A
For operations such as GV and OHV that involve spatial changes such as movement and rotation, the three-dimensional shape of the corresponding production basic element is updated accordingly. Although not displayed on the screen, each control device in the virtual operating system 22 that controls each production basic element executes a control sequence or a control program over time, and changes the internal state or internal variable of each production basic element. To do. And the behavior of each production basic element is the internal state and internal variables of each production basic element,
It can be known from the shape change of each production basic element displayed on the screen.

In the virtual panel 23, various messages, data of internal states and internal variables in each object, various data in windows, etc. can be displayed as required. FIG. 4 is a structural conceptual diagram showing an example of a minimum unit model for forming the cell unit model 21. This model includes an input element 211 for inputting various kinds of information regarding products manufactured by an actual plant.
And a production basic element 212 that is connected to this input element to simulate a product on a production line, an output element 213 that outputs various information output from the production basic element, a control command for the production basic element 212, The control management element 214 handles the control status.

Here, as the information of the input signal handled by the input element 211, the specification information IN of the product to be produced, information (type and quantity) MP of materials and parts, raw material and resource information (resources such as power and water) (Including information) RS, work, quantity, quality, timing, etc. The respective input information can be expressed by the following equations. IN ... f _IN (IN ₁ , IN ₂ , ... IN _n ) Product specification information MP ... f _MP (MP ₁ , MP ₂ , ... MP _n ) Material and parts information RS ... f _RS (RS ₁ , RS ₂ , .. RS _n ) Resource information Note that f is a function, IN ₁ , MP ₁ , RS _1, etc. are parameters, and n is a production line number.

The production basic element 212 is a transportation element 221, an assembly / processing element 222, and a verification element 2 necessary for producing a product.
23, storage element 224, man-made element 225, and the like, each element necessary for simulating a line is included, and these elements are combined to simulate an actual plant. Each of these elements uses the cycle time t as a management parameter and can be expressed by the following equation.

Transport elements Tt ₁ , Tt ₂ , ... Tt _n Machining elements Mt ₁ , Mt ₂ , ... Mt _n Assembly elements At ₁ , At ₂ , ... At _n Verification elements Vt ₁ , Vt ₂ , ... Vt _n storage elements St ₁ , St ₂ , ... St _n manual elements Pt ₁ , Pt ₂ , ... Pt _n Note that T, M, A, V, S, and P are constants.

The information handled by the output element 213 includes the output OP1 of the information processing system, the output OP2 of the manufacturing system such as the production quantity and the number of non-defective products, and the output OP3 of the support system such as exhaust gas, waste liquid, and remaining materials. The respective output information can be expressed by the following equations. Information processing system output _{OP1 ... f OP1 (OP 1,} OP 2, ...... OP n) production system output _{OP2 ... f OP2 (OP 1,} OP 2, ...... OP n) support system output _OP3 ... f OP3 (OP _1, OP ₂ , ... OP _n ) Further, as the information handled by the control management element 214, there are production command information OD, production status information ST and the like. Each of these control controls can be represented as follows and are communicated to the production primitives 212.

Production command OD ... f (OD ₁ , OD ₂ , ... OD _n ) Production status ST ... f (ST ₁ , ST ₂ , ... ST _n ) FIG. 5 is a standard general-purpose production plant in a discrete process. It is a conceptual diagram which shows an example of the unit model which simulated. Here, the production basic elements in the production plant include an information system 212a that focuses on the flow of information (signals), a manufacturing system 212b that focuses on the flow of products (objects), and a support system 212c that focuses on resources such as energy. It is divided into two parts, and each system has a transport element 221, an assembly element 22 and a processing element 22.
2, verification element 223, storage element 224, manual element 225
A model is constructed to simulate the actual production line by appropriately combining the above.

That is, in this production factory, first, materials or parts are transported by the transport element 221 and stored in the storage element 224 such as a store, and subsequently, the material taken out from the storage element is manually processed by the processing and assembly element 222. Element 22
Process by 5. After that, the verification is performed by the verification element 223, and again, in the processing and assembly element 222,
Assemble by 25. After that, the production line is such that it is verified by the verification element 223 and stored in the storage element 224. Here, each element has a constant (T, S, M, etc.) corresponding to each equipment condition (type, number of units, quality, etc.).
V, A, etc.), cycle time, store time, assembly time, handling time (t), etc. are set as parameters.

In the control management element 214, conditions for controlling and managing the production line (for example, waste time, PID constants for control calculation, optimization coefficient, etc.) are set, and each production basic is set. Elements 212a, 212b,
212c is a production command or control signal O output from the control management element 214 based on these control management conditions.
Operates according to D.

In the production basic element 212a of the information system which pays attention to the flow of information (signal), the information input IN such as the product specification is applied from the input element 211 and the output element 213 has a defect in which element of the line, for example. An information processing system output OP1 such as whether it has occurred is output. The production basic element 212b of the manufacturing system, which focuses on the flow of products, receives the information input MP such as the material part product specification from the input element 211, and outputs to the output element 213, for example, how many good products and defective products. The manufacturing system output OP2 is output.

The production basic element 212c of the support system focusing on resources such as energy receives the information input RS such as resources from the input element 211 and outputs the support system output OP3 relating to exhaust gas and waste liquid to the output element 213. . FIG.
It is a functional block diagram which shows an example of the virtual factory means 2. This virtual factory means is a simulation in which a programmable cell unit model 21 simulating an actual plant cell controlled by each plant cell unit controller and a production process of a product produced by an actual plant are simulated using the cell unit model 21. Means 24,
Output information of cell unit model 21 and actual plant PLT
Management parameter correction means 25 that corrects the management parameter of the cell unit model 21 based on the comparison with the output information output from the cell unit model 21.

In the system having such a configuration, it is necessary that the cell unit model 21 and the actual plant PLT have a 1: 1 correspondence. Therefore, first, after determining the respective capacity specifications of the system based on the combination of the devices, equipment, and machines that constitute the simulated plant displayed on the virtual panel 23, the cell unit model 2
The characteristic setting of 1 is performed.

This characteristic setting is performed by the cell unit model 21.
For each parameter to be set to, input conditions, output conditions, control management conditions, etc.
Determine the initial value. Then, while inputting the same information as the input conditions given to the actual plant PLT to the cell unit model 21 in which the initial value is set, artificial fluctuations or step changes are given to these input information, and their outputs are output. While observing the response and repeating the trial and error of the values of the respective management parameters set in the cell unit model 21,
The management parameters are corrected by the management parameter correction means 25, and these management parameters are optimized while learning.

That is, in the cell unit model 21, the difference between the output information from the cell unit model 21 and the output information from the actual plant PLT is eliminated so that various fluctuations and steps are given as input information. Each management parameter to be set is corrected, and finally the optimum cell unit model 21 that matches the actual plant is completed. Figure 7
FIG. 4 is a conceptual diagram showing an algorithm for determining a production pattern on an actual plant PLT production line using the completed cell unit model 21.

First, the item Pn of the product to be produced on the production line is determined (step 1). Here, for example, it is specified that B parts of A parts are to be produced.
The information input information IN, the manufacturing system information MP of materials, parts, etc., the resource information RS, etc., which are each information for producing B parts, are given from the input element 211 to each production basic element 212 as input conditions. To be

Each production basic element 212 receives these input information, and control parameters T.tn, S.tn of each transport element, storage element, etc. constituting the production basic element 212.
A minimization operation is performed that minimizes the cycle time (the shortest time) (step 2). That is, f (Ttn, M
tn, Vtn, Atn, Stn, Ptn) is minimized. The minimization operation here includes the combination of each element and the order of the elements, the rearrangement of the human element, and the exchange of another element, and the well-known fuzzy operation and the operation using the neuron are used as the operation method. It is possible to By such a minimization operation, a combination of the respective elements constituting the production basic element 212 for producing the designated item in the shortest time, and the management parameters set in these respective elements are determined. Also, each output information O based on this
P1, OP2 and OP3 are output respectively.

Here, the finally determined production basic element 2
In 12, when the combination and order of the internal elements are exchanged, the elements of the production line of the actual plant are also rearranged and exchanged accordingly. In addition, the cycle time etc. for each element on the actual production line will be reset. Then, when the respective elements of the production line of the actual plant are rearranged, the correction operation of the management parameter for optimizing the cell unit model 21 as described with reference to FIG. 5 is repeated again.

When the combination of each element constituting the production basic element 212 for producing the designated item in the shortest time and the management parameter set in each element are determined, the production status information from each element and the Output information OP1
The production pattern of the constructed production line is determined by OP3, etc. (step 3). In FIG. 2, the management condition instructing means 3 determines each management condition to be set on the actual plant PLT side on the basis of the determined production pattern and each management parameter set in the cell unit model 21 (step 4). Management conditions (for example, the transfer time of the transfer device, the processing time of the processing / assembling device, the cycle time of each device, the PID operation constant of the control operation device, etc.) via the communication line BS for each plant cell unit controller unit 1 (Step 5).

Each plant cell unit controller section 1 for which the management conditions are set in this way thereafter performs control operation in a self-sustaining distributed manner in accordance with the management conditions. Actual plant P
In the state where the production line is controlled by each plant cell unit controller unit 1 in the LT, it is not necessary to exchange data for control with the virtual factory 2 side.

It should be noted that, if the virtual factory side is configured to periodically receive production status information, control status information, etc. from the actual plant side while the production line is controlled, the transmitted information can be obtained. Based on this, the operation on the actual plant side can be monitored on the virtual panel 23.

[0043]

As described above in detail, according to the present invention, it is possible to construct an optimum production line for a target production brand based on a virtual factory constructed on a computer.
It can be done quickly and without waste. In addition, when the production plan is changed or the production brand is changed, optimal management conditions are required, and the required management conditions are transmitted from the management device side to each independent distributed controller unit. Therefore, it is possible to quickly and accurately respond to flexible production plans and brand changes at low cost.

[Brief description of drawings]

FIG. 1 is a diagram for explaining a production line construction method of the present invention.

FIG. 2 is a configuration block diagram showing an example of a production line management system according to the present invention.

FIG. 3 shows a virtual panel 2 in the virtual factory means 2.
It is a figure which shows an example of the screen displayed on No. 3.

FIG. 4 is a structural conceptual diagram showing an example of a minimum unit model for forming a cell unit model 21.

FIG. 5 is a conceptual diagram showing an example of a unit model simulating a standard general-purpose production factory in a discrete process.

FIG. 6 is a functional block diagram showing an example of virtual factory means 2.

FIG. 7 is a conceptual diagram showing an algorithm for determining a production pattern on a production line of an actual plant PLT using the completed cell unit model 21.

[Explanation of symbols]

OF management device PLT plant or factory BS communication bus 1 plant cell unit controller section 2 virtual manufacturing plant means 21 cell unit model 22 virtual operating system 23 virtual panel 3 management condition instruction means

Claims (6)

[Claims] 1. Storage means for storing production basic elements simulating machines and equipment elements such as a conveyor line, a processing line, an assembly line, an inspection line, etc. that compose a production line, and a plurality of productions read from this storage means. A virtual factory construction means for constructing a virtual production line (virtual factory) by combining basic elements, and a simulation means for simulating product production using the constructed virtual factory are provided. A first step of constructing a virtual factory by combining elements according to the flow of product production, a second step of simulating a product production process by a simulation means using the virtual factory constructed by the first step, and each production In order to minimize the cycle time set for the basic element, the first step and the second step Step 3 is repeated to determine a combination of production basic elements that minimizes the cycle time, and an actual production line is constructed based on the combination of production basic elements determined in the third step. A method for constructing a production line, including the steps of 4. 2. An apparatus comprising a plurality of self-sustaining distributed plant cell unit controller sections and a management apparatus which is connected to each of these plant cell unit controller sections via a communication line to instruct management conditions. In the management device, storage means for storing production basic elements simulating machines and equipment elements such as a conveyor line, a processing line, an assembly line, and an inspection line that compose a production line, and a plurality of storage devices read from the storage means. The virtual factory construction means for constructing a virtual production line (virtual factory) by combining production basic elements, the simulation means for simulating product production using the constructed virtual factory, and the management conditions obtained in the virtual factory are described above. The provision of management condition instruction means for downloading to each plant cell unit controller section via a communication line Production line management system for the butterflies. 3. A programmable cell unit model,
An input element for inputting at least information about product specifications and material information produced by an actual plant, and by combining these input elements with the transport, processing, assembly, and other processes required for product production.
It is composed of a production basic element that simulates a line for inspection, an output element that outputs various information output from the production basic element, and a control management element that handles control commands and control status for the production basic element. The production line management system according to claim 2. 4. A virtual factory simulates a programmable cell unit model simulating an actual plant cell controlled by each plant cell unit controller and a manufacturing process of a product produced by an actual plant using the cell unit model. 3. A simulation means, and a control parameter correction means for correcting the control parameter of the cell unit model based on a comparison between the output information of the cell unit model and the output information output from the actual plant. Production line management system. 5. A virtual factory receives information on a specified product brand to be produced, and minimizes the time required for each of the production line basic element production line, such as the transfer line, processing line, assembly line, and inspection line, which produces the product brand. The production line management system according to claim 2, wherein the production pattern is defined as follows, an actual production line is configured based on the determined production pattern, and a management condition of the configured actual production line is determined. 6. A production basic element in a virtual factory is a transportation element,
3. The production line management system according to claim 2, comprising a processing / assembly element, a storage element, a verification element, and a manual element, and these elements are combined to form a basic production element.