**6. Petri networks in computer integration manufacturing**

Computer integration manufacturing (CIM) involves the integration of technical systems of constructing a product, planning a manufacturing process, technical preparation of production, programming CNC equipment, manufacturing, assembly, ensuring quality control, monitoring [35] and testing a product with facility and organizational systems of planning and controlling production in a company. Such integration should be implemented based on a shared, coherent system of databases: structural ones, ones for manufacturing processes, resource of production and transport, tools, processing and measuring equipment. Possible scope of modeling using the Petri network technique with respect to issues related to computer integration of manufacturing is very broad nowadays. The use of graphic tools such as the Update Petri Nets (UPN) class [36] based on Color Petri Networks (CPN) might be used as an example. UPN applications are systems based on rules, integrating control of information flow between CAD, CAPP, resources management and production flow.

A data exchange system between individual modules is a prerequisite for integration. It is still the weakest link of the contemporary computer integration systems. Currently, the bottleneck of integration might be removed, after introducing and popularization of the Automation Markup Language (AML). IEC 62714 [37] project available since 2014 is a solution for data exchange concentrating on the area of industrial automation. The document defines AML data exchange format based on Extensible Markup Language (XML) scheme data format. It has been developed to support data exchange for heterogeneous engineering tools in the environment of automated production resource. The objective of AML is to combine engineering tools of various fields, that is, mechanical engineering, workshop design, electric engineering, production process design, controlling course of production, development of human machine interface (HMI), programmable logic controller (PLC) programming, programming CNC machine tools and industrial robots, and so on. AML might describe both physical and logical aspects of all components of a production system, their topology, geometry, kinematics, logics of control, and represent the links and hierarchy of all objects considered. It should be emphasized that XML format serving as a base for AML language has been developed since 1990, mostly as a spontaneous initiative of engineers dissatisfied with previously offered solutions, including standard for the exchange of product model data (STEP). The success of XML format is a result of flexibility of the language, ease of defining complex data structures, lack of barriers in other suggested solutions, its alphanumeric character, ease of control and direct analysis, open and intuitive character. Solutions have been put forward for several years, also in the form of standards, presenting data representation for the Petri network model in a format based on the Petri Net Markup Language (PNML) [38]. PNML has been introduced as a data exchange format for all Petri network classes. All of this is a fundamental premise for formulating a favorable forecast for acceptance and quick popularization of AML language as a data exchange language in industrial automation and its environment.

use fuzzy conjunction. Its CF is a product of premises of the rule and the CF of the very rule. If a conclusion is supported by two (**Figure 6b**) or more rules, fuzzy disjunction should be used. Its CF is a soft logical sum of indices generated by each of the rules separately. If the CF of transition is negative, what we have is a fuzzy negation (**Figure 6c**). All the three aggregation functions ensure maintaining CF between 0 and 1. Contrary to the previously presented PN1

The threshold value of certainty indices is defined as global for the entire network. **Table 2** presents a description and list of CF for the shown example. **Figure 7** puts forward a fragment of the manufacturing knowledge database related to the method of mounting parts on a lathe,

Computer integration manufacturing (CIM) involves the integration of technical systems of constructing a product, planning a manufacturing process, technical preparation of production, programming CNC equipment, manufacturing, assembly, ensuring quality control, monitoring [35] and testing a product with facility and organizational systems of planning and controlling production in a company. Such integration should be implemented based on a shared, coherent system of databases: structural ones, ones for manufacturing processes, resource of production and transport, tools, processing and measuring equipment. Possible scope of modeling using the Petri network technique with respect to issues related to computer integration of manufacturing is very broad nowadays. The use of graphic tools such as the Update Petri Nets (UPN) class [36] based on Color Petri Networks (CPN) might be used as an example. UPN applications are systems based on rules, integrating control of information

A data exchange system between individual modules is a prerequisite for integration. It is still the weakest link of the contemporary computer integration systems. Currently, the bottleneck of integration might be removed, after introducing and popularization of the Automation Markup Language (AML). IEC 62714 [37] project available since 2014 is a solution for data exchange concentrating on the area of industrial automation. The document defines AML data exchange format based on Extensible Markup Language (XML) scheme data format. It has been developed to support data exchange for heterogeneous engineering tools in the environment of automated production resource. The objective of AML is to combine engineering tools of various fields, that is, mechanical engineering, workshop design, electric engineering, production process design, controlling course of production, development of human machine interface (HMI), programmable logic controller (PLC) programming, programming CNC machine tools and industrial robots, and so on. AML might describe both physical and logical aspects of all components of a production system, their topology, geometry, kinematics, logics of control, and represent the links and hierarchy of all objects considered. It should be emphasized that XML format serving as a base for AML language has been developed since 1990, mostly as a spontaneous initiative of engineers dissatisfied with previously offered solutions, including standard for the exchange of product model data (STEP). The success of XML format is a result of flexibility of the language, ease of defining complex data structures, lack of barriers in other suggested solutions, its alphanumeric character, ease of control and direct

class cannot include a loop. It is also allowed that a graph is inconsistent.

and PN2

classes, PN3

50 Petri Nets in Science and Engineering

developed using the mechanism presented above.

**6. Petri networks in computer integration manufacturing**

flow between CAD, CAPP, resources management and production flow.

**Figure 8** shows a scheme of an integrated production unit design system, taking into account data exchange streams and main functions of individual modules. Attention should be drawn

**Figure 8.** Data exchange streams in integrated manufacturing cell planning system.

to the role of a spreadsheet with active macro application option, which allows to compile input data for computer aided design (CAD) and computer aided manufacturing (CAM) systems and control their correctness, completeness, consistency and adherence with the allowed range. Diagnostics of data is a significant element that influences comfort of using the design system. Full integration of a spreadsheet with popular CAD systems is possible nowadays, which significantly facilitates structural designing and drawing up documentation in the form of drawings. At the same time, a spreadsheet allows for drawing up a data file for a parametrized program of processing a selected class of produced machine parts by using related data sheets. An Excel Macro-Enable Workbook (XLSM) format file allows to use macros, that is, command sequences that might be used for the automation of completed functions in a spreadsheet. A 3D model is made by preparing a drawing in CAD program, which is integrally linked to the data included in the spreadsheet's data file. Then, 2D documentation is made based on such model, if it is necessary. The code generated in a spreadsheet has a simple structure in the form of a list of R-parameters plus the name of a processed part. These are input data for CAM system and/or the numerical control system of the machine tool, where parametric programs related to the aforementioned list of variable parameters are archived. Aside from formal verification of the controlling program's form, processing in CAM aims at providing a simulation of processing. Aside from confirming correctness of programmed trajectories of a machine's movement, the simulation made provides an exact completion time for individual processing operations. The results are exported to the Petri Nets Modeler (PNM) package, which allows for exact time simulation of a production unit's work. A list of Petri network model transitions in XML format are again transferred to the spreadsheet, thus closing the process chain. It includes a list of transitions with their completion times and a number of repetitions in a given period. A spreadsheet allows to easily obtain a clearly structured document presenting, for example, utilization rate on production resource (**Figure 5**).

detail, graphic user interface at the stage of acquisition, verification and processing a model, ease of modification and expansion of a model using its hierarchical and block character. The fact that each model contains production knowledge is the greatest advantage of applying modeling techniques in the planning of production processes. Hence, the premises for automation of the design process, at least in the area of implementing routine works. An engineer's intellectual efforts might therefore be aimed at introducing innovative solutions and improvements.

Petri Networks in the Planning of Discrete Manufacturing Processes

http://dx.doi.org/10.5772/intechopen.75135

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**Author details**

Roman Stryczek

**References**

University of Bielsko-Biala, Poland

10.1007/BF02601620

262. DOI: 10.1007/BF01186876

net/publication/268259692 [Accessed: 2015-01-19]

0965-9978(95)00086-0

9978(98)00126-4

387-34919-0\_14

Address all correspondence to: rstryczek@ath.bielsko.pl

the CIRP. 1988;**37**:1-11. DOI: 10.1016/S0007-8506(07)60756-2

PNM package is a key module of the presented design system. Its objective consists of computer simulation, modeling and optimizing of both individual and group processes of production, dedicated to autonomous flex-cells, multi-machine tool stations and robotized manufacturing systems.
