Object-oriented Petri Net Model Research Articles

Research and development of monitoring system and data monitoring system and data acquisition of CNC machine tool in intelligent manufacturing

Intelligent manufacturing as the development direction of the new generation manufacturing system has become a hot research topic. Computer numerical control (CNC) machine tools are the core manufacturing equipment in discrete manufacturing enterprises, collecting and monitoring the data is an important part of intelligent manufacturing workshops. It has a great significance to improve the production efficiency of enterprises and eliminate information islands. The purpose of this article is to solve the problems of data acquisition and monitoring of CNC machine tools in the manufacturing workshop of enterprises. This article uses FOCAS data acquisition method to research and develop the data acquisition and monitoring system of CNC machine tools in intelligent manufacturing workshop. The research results show that the equipment information model based on MTConnect protocol and FOCAS can solve the data acquisition and storage functions of CNC machine tools well. Using the object-oriented Petri net model, it can solve various uncertain factors in numerical control (NC) machining tasks and realize the monitoring function of CNC machining tasks in the workshop. Based on the NC program analysis, the calculation method of machining time in the NC program can determine the preventive maintenance cycle of the machine based on the machine fault information. Based on VS2013 development environment, Qt application framework and SQL Server 2012 database, the numerical control machine tool data acquisition and monitoring prototype system was developed, and the system was verified in the workshop to prove the effectiveness of the system.

An extended object-oriented petri net model for mission reliability evaluation of phased-mission system with time redundancy

Phased-mission system (PMS) has been widely used as mission reliability model of many engineering mission-critical systems. In practical, PMS can have time redundancy both inner phase and between phases, i.e. the success of one phase may only require the system to keep operational for a given time interval instead of working throughout the phase. Besides, mission task failed in one phase can be re-executed in a later phase with change of its configurations.Based on the extended object-oriented Petri net (EOOPN), this paper proposes a general modeling procedure for mission reliability evaluation of PMS, which is capable of considering the time redundancy both inner phase and between phases in relatively intuitive way. The proposed approach is performed in system, phase and component levels. The system level depicts all possible executable paths of PMS via the token transition between different EOOPN subnets, including the re-execution arrangement of failed mission tasks. The phase level details the model structure of each EOOPN subnet, which addresses the system state change process and the minimal operational time requirement of a phase. The component level describes components state change during the mission. A discrete-event simulation is applied to the constructed EOOPNs for system mission reliability evaluation, and an example system under different time redundancy assumptions is analyzed to illustrate the effectiveness of this approach.

Computer Network Simulation Modeling Based on Object Oriented Petri Net

This paper first briefly introduces the Petri net, and then studied in detail according to the selected object-oriented Petri net modeling method. This paper improve the object-oriented Petri net modeling method, and study the modeling and operation steps in details. Finally this paper build a computer network TCP/IP protocol model based on the object oriented Petri net. The model prove to be a good simulation to the computer network and the improved modeling method is also a valid method for further object oriented Petri net modeling.

Extended object-oriented Petri net model for mission reliability simulation of repairable PMS with common cause failures

Phased Mission Systems (PMS) have several phases with different success criteria. Generally, traditional analytical methods need to make some assumptions when they are applied for reliability evaluation and analysis of complex PMS, for example, the components are non-repairable or components are not subjected to common cause failures (CCF). However, the evaluation and analysis results may be inapplicable when the assumptions do not agree with practical situation. In this article, we propose an extended object-oriented Petri net (EOOPN) model for mission reliability simulation of repairable PMS with CCFs. Based on object-oriented Petri net (OOPN), EOOPN defines four reusable sub-models to depict PMS at system, phase, or component levels respectively, logic transitions to depict complex components reliability logics in a more readable form, and broadcast place to transmit shared information among components synchronously. After extension, EOOPN could deal with repairable PMS with both external and internal CCFs conveniently. The mission reliability modelling, simulation and analysis using EOOPN are illustrated by a PMS example. The results demonstrate that the proposed EOOPN model is effective.

Automated generation of mission reliability simulation model for space tracking, telemetry and control system by extensible markup language and extended object-oriented Petri net

To evaluate and optimize the space tracking, telemetry and command system design, it is important to perform mission reliability analysis of tracking, telemetry and command system. Considering the complexity of tracking, telemetry and command system configuration and mission process, it is nearly infeasible to model and analyze the system by manual work. For accuracy and efficiency reasons, system designers need to have an integrated set of methods and tools for modeling specifications and performing reliability analysis. This article presents an XML-based (extensible markup language–based) schema named reliability modeling language to formally represent data and information, which are necessary for building the mission reliability model of tracking, telemetry and command system. To facilitate the evaluation of mission reliability measures, we propose the improved extended object–oriented Petri net formalism, which is an extension of object-oriented Petri net to perform mission reliability simulation and analysis. The standard descriptive model in reliability modeling language can be automatically and directly transformed into an extended object–oriented Petri net model by applying model transformation rules and algorithm. The proposed approach is illustrated and validated by examples, which consider the complex situation such as component phase dependence, non-exponential failure rate, instantaneous repair as well as different work start and end time. The simulation results show a good approximation compared with the results of analytical models.

Hybrid Simulation Based Approach for Embedded Systems Reliability Analysis

This paper describes a reliability approach based on a coupling of discrete and continuous dynamics simulation of embedded systems. This hybrid simulation is a combination in the same formalism of the discrete simulation of an algorithm allowing the extraction of feared scenarios that lead an embedded system to a critical situation without generating the associated reachability graph in order to avoid the eternal combinative explosion problem, and, the continuous dynamics of the embedded system represented by a Java code. The simulation of discrete and continuous dynamics is coupled in object-oriented stopwatch Petri net models that allow the representation of the suspension and resumption of task execution.

Study of Re-Entrant Lines Modeling Based on Object-Oriented Petri Net

This article puts forward object-oriented Petri net modeling method, which possesses good encapsulation and modularity compared with current ordinary modeling method. On the macro level, it divides the re-entrant lines into different object modules according to the technology, so that the complexity of models is largely reduced through message delivery between objects. In the micro level, it explains objects' internal operational mechanism, in another word, each object's internal operation cannot be affected by other objects and environment. At last, it makes modeling and dynamic analysis by taking LED chips' processing flow for example, showing that re-entrant lines model based on object-oriented Petri net possesses good modeling ability.

A Survey on the Object-Oriented Petri Net Modeling

With the larger and more complex of the size and function of software products，choosing an efficient modeling technique for analyzing complicated and ever-changing system plays a vital role．Object-Oriented Petri nets for its unique characteristics which are simple and laconic modeling method and strong mathematical analysis capacity becomes a hot research．In this paper，it explain that the object-oriented technology how to combine with Petri nets．The typical Object-Oriented Petri net modeling steps and analysis methods are expounded. Up-to-date research about OOPN and its main improved models OOCPN, OOAPN and OOTPN are summarized, the pros and cons of each modeling are analyzed．The interrelated topics and the future development about OOPN are also mentioned．

Research on Manufacture Processes of Resin Dry Transformers Based on Object-Oriented Petri Net

The models of resources and manufacturing processes, which aim at the production system of the resin dry transformers, are constructed by Object-oriented Petri Net (OPN) in this paper. SCB9 1000/10 400(Cu) transformer is taken as case study, the flow chart of manufacturing transformers are described at first, and then researched by static analysis, dynamic analysis and integrated application in details. The conflicts of the OPN models, which may happen in all manufacturing system of resin dry transfers, have been resolved. The whole manufacturing system are improved and optimized in the manufacture processes at last.

Object-Oriented Petri Net Modeling and Analysis of China Railway Container Freight Yard Logistic System

The railway container freight yard logistic system is a typical discrete event dynamic system (DEDS) and has the feature of high randomness, low flexibility, uncertainty of operation time and high coordination demand of facilities. Object-oriented petri net (OPN) inherits the petri net (PN) advantages for efficiently describing the asynchronism, concurrency, distributivity, parallel DEDS and overcomes the disadvantages when faces complex discrete element dynamic system. We choose object-oriented petri net to model and analyze China railway container freight yard logistic system and get the object OPN model and communication relation net.

Dynamic Simulation of the Equipment Repair Support System based on the OPN Model

It is more difficult that mathematical method analyzes the Object-oriented Petri Net (OPN) model of equipment repair support system which is enormous and complicated, the thread and concrete operation method to apply CPN- Tools simulation software in simulating and analyzing its OPN model was put forward. According to the thread of simulating and concrete operation method, it was successful to construct the Colored Petri Net (CPN) model of the example OPN model of equipment repair support system and verify its dynamic performance with CPN-Tools. Then, it concludes that the method of simulation analysis for the OPN model is rational and effective.

Modeling Method of Automotive Body CAN/LIN Nets Application Protocol Based on Object-oriented Colored Petri Net

Recently automotive nets are adopted to solve increasing problems in automotive electronic systems.Technologies of automotive local area network from CAN and LIN can solve the problems of the increasing of wire bunch weight and lack in module installation space.However,the multilayer automotive nets software becomes more and more complex,and the development expense is difficult to predict and to keep in check.In this paper,the modeling method of hierarchical automotive nets and the substitution operation based on object-oriented colored Petri net(OOCPN) are proposed.The OOCPN model which analyzes the software structure and validates the collision mechanism of CAN/LIN bus can speed the automobile system development.First,the subsystems are divided and modeled by object-oriented Petri net(OOPN).According to the sets of message sharing relations,the message ports among them are set and the communication gate transitions are defined.Second,the OOPN model is substituted step by step until the inner objects in the automotive body control modules(BCM) are indivisible and colored by colored Petri net(CPN).And the color subsets mark the node messages for the collision mechanism.Third,the OOCPN model of the automotive body CAN/LIN nets is assembled,which keeps the message sets and the system can be expanded.The proposed model is used to analyze features of information sharing among the objects,and it is also used to describe each subsystem real-time behavior of processing messages and implemental device controllers operating,and puts forward a reasonable software framework for the automotive body control subsystem.The research can help to design the communication model in the automotive body system effectively and provide a convenient and rapid way for developing the logical hierarchy software.

Simulation and Optimization of Job Shop Scheduling for Dry Transformers Based on eM-Plant

The model of job shop scheduling to fabricate dry transformers is constructed by Object-oriented Petri Net (OPN) in this paper, the essential attributes and ways of all object classes are defined to judge if there is a deadlock in the system. The overall OPN model of job shop scheduling is built according to relations of event actions in the manufacturing system. Product processes in the job shop is simulated by eM-Plant software to reconstruct and optimize the manufacturing system at last.

An integrated object-oriented approach for design and analysis of an agile manufacturing control system

The agile manufacturing paradigm has emerged as an important concept in the development of manufacturing systems. The control software, developed based on the object-oriented technology, leads to reusability, reconfigurability, and scalability; and the agility of a manufacturing control system can be achieved. In this research, an efficient and systematic methodology for developing an object-oriented agile manufacturing control system is proposed. The proposed development process is divided into four stages: functional analysis, static structural analysis, behavior analysis and verification, and system implementation. The Integration Definition for Function Modeling (IDEF0), Object-Oriented Petri Net (OPN), and Unified Modeling Language (UML) are integrated into the corresponding stages based on their characteristics. In order to develop the system rapidly and efficiently, the transformation rules between the IDEF0 and OPN, and between the OPN and sequence diagram are conducted. In addition, the attributes and operations for each object are also defined directly from the OPN model. The result of the integrated IDEF0/OPN/UML systematically leads to object-oriented control software design for manufacturing systems. Finally, an assembly and packaging system is given to illustrate how the integrated object-oriented approach is implemented for developing the manufacturing control system.

The research on modeling of coal supply chain based on objectoriented Petri net and optimization

Object-oriented Petri Net modeling of coal supply chain system can be established from the perspective of workflow by applying the technology of object-orientation and Petri net. On the basis of the modeling, profit maximization optimization for the selection of resources and the environment in a certain condition to meet customer demand is taken as the coal supply chain optimization objective. And under the quantitative description and analysis of the internal nodes, logistics, capital flow and information flow in coal supply chain system, the optimal method is used for objective optimization. Through this research, we have learned that the use of the method in coal supply chain modeling and objective optimization can accurately reflect the operation of the coal supply chain and its resource constraints, which will finally improve decision-making performance. The complex systems can be highly abstracted by using this OPN model which is also easy for expansion and optimization model has a strong versatility.

Implementation of a SCADA System for Flexible Manufacturing Systems using object-oriented Petri nets model

This work proposes the implementation of a Supervisory, Control and Data Acquisition (SCADA) System for a Flexible Manufacturing System (FMS) based on an object-oriented Petri Net model of the plant. Considering the complexity of a FMS (different types of parts and raw materials, different schedules, processes and programs to deal with, ways of handling parts, etc.), the implementation of a SCADA System to manage and control the plant is complex and susceptible to errors, even deadlocks. The creation of a program based on a formal model capable of dealing with such complexity and problems minimizes mistakes and allows such a model to be simulated, anticipating error situations and its possible solutions. The editing and debugging processes are also facilitated, as well as the inclusion of new types of parts or processes that can be easily performed by the definition of new attributes and methods according to the model. The analysis of the program performance is carried out using a formal methodology based on the model. A case-study implementation is shown for demonstration and validation purposes.

Internet-enabled modelling of extended manufacturing enterprises using process-based techniques

This article presents the preliminary results of an ongoing research project on Internet-enabled process-based modelling of extended manufacturing enterprises. We propose applying the open system architecture for CIM (CIMOSA) modelling framework alongside object-oriented Petri net models of enterprise processes and object-oriented techniques for extended enterprises modelling. We describe the main features of the proposed approach and discuss some components. We present elementary examples of object-oriented Petri net implementation and real-time visualisation.

Object-oriented development of the embedded system based on Petri-nets

Embedded systems are an emerging field that has commanded attention and support from the industrial community. They have been a part of daily life today. However, complex behaviors and a lack of reusability and modularization have been obstacles to the development of successful embedded systems. A typical issue or challenge of embedded system design lies on the synthesis of software and hardware. Currently, a paradigm shift towards object-oriented (OO) techniques has been advocated in hope of increasing the reusability and modularization. In this paper, an object-oriented development method of the embedded system based on Petri-nets is proposed. The concurrent ability of Petri-nets assists the concurrent co-design of embedded systems synchronously. In addition, the paper applies the reachability tree and the generalized label-correcting (GLC) algorithm to analyze and to validate the designed processes in object-oriented Petri-net models. This solution approach is novel in a sense that by combining various operators and comparators, different types of developing problems in embedded systems can be solved with one algorithm for different values of the initial node.

An Object-Oriented Model for Rapid Prototyping of Data Path/Control Systems – A Case Study

The aim of this article is to present how to use shobi-PN, an Object Oriented Petri Net model to specify data path/control systems. In a case study, a transputer link adaptor is specified for rapid-prototyping by applying the shobi-PN model and the generation of VHDL code for simulation is presented. The case study demonstrates the applicability and the capability of a development process, supported by the use of object-oriented principles to model both the control unit and the data path of complex systems, with a developed CAD tool

Object-oriented Petri nets for modelling and analysis of automated manufacturing systems

This paper presents an Object-oriented Petri Net (OPN) approach to model and analyse the dynamic behaviours of an Automated Manufacturing System (AMS). Both the basic and the complete OPN models are introduced to represent the generic and specific dynamic behaviours of an AMS, respectively. Based on the basic OPN model, we need to construct the Object Communication Net (OCNet) for each physical object, and then employ the theory of invariants to perform the deadlock analysis. For an analysed non-deadlock basic OPN model, the complete OPN model for a specific AMS may be effectively derived from it by only including those related system constraints (e.g. part routing, resource capacity), since the basic OPN class library is reusable. A conflict analysis approach is then introduced to identify all the conflicting events involved in the complete OPN model, so that the most suitable control/decision strategy for resolving each conflict event may be suggested. Consequently, a rule-based control software may be implemented directly from the specification of the validated complete OPN model by following a number of transformation rules.