The Experts below are selected from a list of 17109 Experts worldwide ranked by ideXlab platform
Mengchu Zhou - One of the best experts on this subject based on the ideXlab platform.
-
a petri net based heuristic algorithm for realizability of target refining schedule for oil refinery
IEEE Transactions on Automation Science and Engineering, 2008Co-Authors: Mengchu Zhou, Feng ChuAbstract:In Discrete Manufacturing, a just-in-time schedule is pursued so as to respond better to the market. It is also required in oil refinery. However, the existing techniques for short-term scheduling in oil refinery are based on the push production mode. This paper addresses the short-term scheduling problem for crude oil operations in a pull production way. A target refining schedule resulting from production planning is given as a constraint to make an executable schedule. The system is modeled by a timed hybrid Petri net. This model is structurally simple and can describe the dynamic behavior and all the constraints of the system without any difficulty. Based on the model, an efficient heuristic algorithm is proposed to test the realizability of a target refining schedule. If it is realizable, a feasible short-term schedule realizing it is created. A real-life industrial case study is presented to show the industrial application of the proposed method.
-
deadlock control policy for a class of petri nets without complete siphon enumeration
Iet Control Theory and Applications, 2007Co-Authors: Mengchu Zhou, Murat UzamAbstract:Siphons are special structures of a Petri net. Their number grows exponentially with the net size. Hence, the traditional siphon-based deadlock control policies have two problems, that is, generating very structurally complex supervisory controllers and requiring intractable computation efforts. This paper intends to use the newly proposed concept, elementary siphons, and a mixed integer programming (MIP) method to design structurally simple supervisory controllers and reduce the computational burden. This method is applicable to a class of Petri nets, System of Simple Sequential Processes with Resources that can well model a wide class of Discrete Manufacturing systems. Siphons are divided into elementary and dependent ones. The proposed policy consists of three stages: siphon control, control-induced siphon control, and the elimination of control-redundant monitors. First, a monitor (control place) is added for each elementary siphon such that it is invariant-controlled. Because of the addition of monitors to the plant model, control-induced siphons are possibly generated in the augmented net. Next, monitors are added to make control-induced siphons in the augmented net always marked sufficiently without generating new problematic siphons. A MIP technique is used to guarantee that no siphon is insufficiently marked. Finally, we systematically remove control-redundant monitors. Compared with previous work in the literature, the deadlock prevention policy developed in this paper can lead to a structurally simple liveness-enforcing Petri net supervisor with more permissive behaviour by adding only a small number of monitors and arcs. Moreover, complete siphon enumeration is avoided. A Manufacturing system example is utilised to illustrate the proposed methods.
-
deadlock control methods in automated Manufacturing systems
Systems Man and Cybernetics, 2004Co-Authors: Maria Pia Fanti, Mengchu ZhouAbstract:As more and more producers move to use flexible and agile Manufacturing as a way to keep them with a competitive edge, the investigations on deadlock resolution in automated Manufacturing have received significant attention for a decade. Deadlock and related blocking phenomena often lead to catastrophic results in automated Manufacturing systems. Their efficient handling becomes a necessary condition for a system to gain high productivity. This paper intends to present a tutorial survey of state-of-the art modeling and deadlock control methods for Discrete Manufacturing systems. It presents the updated results in the areas of deadlock prevention, detection and recovery, and avoidance. It focuses on three modeling methods: digraphs, automata, and Petri nets. Moreover, for each approach, the main and relevant contributions are selected enlightening pros and cons. The paper concludes with the future research needs in this important area in order to bridge the gap between the academic research and industrial needs.
-
comparing ladder logic diagrams and petri nets for sequence controller design through a Discrete Manufacturing system
IEEE Transactions on Industrial Electronics, 1994Co-Authors: Kurapati Venkatesh, Mengchu Zhou, R J CaudillAbstract:Design methods for sequence controllers play a very important role in advancing industrial automation. The increasing complexity and varying needs of modern Discrete Manufacturing systems have challenged the traditional design methods such as the use of ladder logic diagrams (LLDs) for programmable logic controllers. The methodologies based on research results in computer science have recently received growing attention by academic researchers and industrial engineers in order to design flexible, reusable, and maintainable control software. Particularly, Petri nets are emerging as a very important tool to provide an integrated solution for modeling, analysis, simulation, and control of industrial automated systems. This paper identifies certain criteria to compare LLDs and Petri nets in designing sequence controllers and responding to the changing control requirements. The comparison is performed through a practical system after introducing "real-time Petri nets" for Discrete-event control purposes. The results reported in this paper will help: (a) further establish Petri net based techniques for Discrete-event control of industrial automated systems; and (b) effectively convince industrial practitioners and researchers that it is worthy and timely to consider and promote the applications of Petri nets to their particular Discrete-event control problems. >
Murat Uzam - One of the best experts on this subject based on the ideXlab platform.
-
deadlock control policy for a class of petri nets without complete siphon enumeration
Iet Control Theory and Applications, 2007Co-Authors: Mengchu Zhou, Murat UzamAbstract:Siphons are special structures of a Petri net. Their number grows exponentially with the net size. Hence, the traditional siphon-based deadlock control policies have two problems, that is, generating very structurally complex supervisory controllers and requiring intractable computation efforts. This paper intends to use the newly proposed concept, elementary siphons, and a mixed integer programming (MIP) method to design structurally simple supervisory controllers and reduce the computational burden. This method is applicable to a class of Petri nets, System of Simple Sequential Processes with Resources that can well model a wide class of Discrete Manufacturing systems. Siphons are divided into elementary and dependent ones. The proposed policy consists of three stages: siphon control, control-induced siphon control, and the elimination of control-redundant monitors. First, a monitor (control place) is added for each elementary siphon such that it is invariant-controlled. Because of the addition of monitors to the plant model, control-induced siphons are possibly generated in the augmented net. Next, monitors are added to make control-induced siphons in the augmented net always marked sufficiently without generating new problematic siphons. A MIP technique is used to guarantee that no siphon is insufficiently marked. Finally, we systematically remove control-redundant monitors. Compared with previous work in the literature, the deadlock prevention policy developed in this paper can lead to a structurally simple liveness-enforcing Petri net supervisor with more permissive behaviour by adding only a small number of monitors and arcs. Moreover, complete siphon enumeration is avoided. A Manufacturing system example is utilised to illustrate the proposed methods.
-
Discrete event control system design using automation Petri nets and their ladder diagram implementation
The International Journal of Advanced Manufacturing Technology, 1998Co-Authors: Murat Uzam, A.h. JonesAbstract:As automated Manufacturing systems become more complex, the need for an effective design tool to produce both high-level Discrete event control systems (DECS) and low-level implementations becomes more important. Petri nets represent the most effective method for both the design and implementation of DECSs. In this paper, automation Petri nets (APN) are introduced to provide a new method for the design and implementation of DECSs. The APN is particularly well suited to multiproduct systems and provides a more effective solution than Grafcet in this context. Since ordinary Petri nets do not deal with sensors and actuators of DECSs, the Petri net concepts are extended, by including actions and sensor readings as formal structures within the APN. Moreover, enabling and inhibitor arcs, which can enable or disable transitions through the use of leading-edge, falling-edge and level of markings, are also introduced. In this paper, the methodology is explained by considering a fundamental APN structure. The conversion of APNs into the IEC1131-3 ladder diagrams (LD) for implementation on a PLC is also explained by using the token passing logic (TPL) concept. Finally, an illustrative example of how APNs can be applied to a Discrete Manufacturing problem is described in detail.
-
petri net based supervisory control of Discrete event systems and their ladder logic diagram implementations
1998Co-Authors: Murat UzamAbstract:The last decade has witnessed rapid developments in computer technology, which in return, has found widespread applications in Manufacturing systems, communication networks, robots etc. Such systems are called Discrete Event Systems (DESs), in which properties such as non-determinism, conflict and parallelism are exhibited. As DESs become more complex, the need for an effective design tool and its implementation becomes more important. Supervisory control theory, based on finite state machines (FSM) and formal languages, is a well established framework for the study of DESs. In supervisory control, given a model of the system and the desired system behaviour specifications, the objective is to find a supervisor (controller) such that the controlled behaviour of the system does not contradict the specifications given and does not unnecessarily constrain the behaviour of the system. In general, the classes of specifications that have been considered within the supervisory control fall into two categories: the forbidden state problem, in which the control specifications are expressed as forbidden conditions that must be avoided, and the desired string problem, in which the control specifications are expressed as sequence of activities that must be provided. In supervisory control, there are some problems when using FSMs as an underlying modelling tool. Firstly, the number of states grows exponentially as the system becomes bigger. Secondly, FMSs lack from graphical visivalisation. To overcome these problems Petri nets have been considered as an alternative modelling tool for the analysis, design and implementation of such DESs, because of their easily understood graphical representation in addition to their well formed mathematical formalism. The thesis investigates the use of Petri nets in supervisory control. Both the forbidden state problem and the desired string problem are solved. In other words, this work presents systematic approaches to the synthesis of Petri-nets-based supervisors (controllers) for both the forbidden state problem and the desired string problem and introduces the details of supervisory design procedures. The supervisors obtained are the form of a net structure as oppose to supervisors given as a feedback fiinction. This means that a controlled model of the system can be constructed and analysed using the techniques regarding to Petri net models. In particular the thesis considers Discrete Manufacturing systems. The results obtained can be applied to high level control of Manufacturing systems, where the role of the supervisor is to coordinate the control of machines, robots, etc. and to low-level control of Manufacturing systems, where the role of the supervisor is to arrange low-level interactions between the control devices, such as motors, actuators, etc. An approach to the conversion from the supervisors to ladder logic diagrams (LLDs) for implementation on a programmable logic controller (PLC) is proposed. A Discrete Manufacturing system example is then considered. The aim of this is to illustrate the applicability, strengths and drawbacks of the design techniques proposed.
R J Caudill - One of the best experts on this subject based on the ideXlab platform.
-
comparing ladder logic diagrams and petri nets for sequence controller design through a Discrete Manufacturing system
IEEE Transactions on Industrial Electronics, 1994Co-Authors: Kurapati Venkatesh, Mengchu Zhou, R J CaudillAbstract:Design methods for sequence controllers play a very important role in advancing industrial automation. The increasing complexity and varying needs of modern Discrete Manufacturing systems have challenged the traditional design methods such as the use of ladder logic diagrams (LLDs) for programmable logic controllers. The methodologies based on research results in computer science have recently received growing attention by academic researchers and industrial engineers in order to design flexible, reusable, and maintainable control software. Particularly, Petri nets are emerging as a very important tool to provide an integrated solution for modeling, analysis, simulation, and control of industrial automated systems. This paper identifies certain criteria to compare LLDs and Petri nets in designing sequence controllers and responding to the changing control requirements. The comparison is performed through a practical system after introducing "real-time Petri nets" for Discrete-event control purposes. The results reported in this paper will help: (a) further establish Petri net based techniques for Discrete-event control of industrial automated systems; and (b) effectively convince industrial practitioners and researchers that it is worthy and timely to consider and promote the applications of Petri nets to their particular Discrete-event control problems. >
Kurapati Venkatesh - One of the best experts on this subject based on the ideXlab platform.
-
comparing ladder logic diagrams and petri nets for sequence controller design through a Discrete Manufacturing system
IEEE Transactions on Industrial Electronics, 1994Co-Authors: Kurapati Venkatesh, Mengchu Zhou, R J CaudillAbstract:Design methods for sequence controllers play a very important role in advancing industrial automation. The increasing complexity and varying needs of modern Discrete Manufacturing systems have challenged the traditional design methods such as the use of ladder logic diagrams (LLDs) for programmable logic controllers. The methodologies based on research results in computer science have recently received growing attention by academic researchers and industrial engineers in order to design flexible, reusable, and maintainable control software. Particularly, Petri nets are emerging as a very important tool to provide an integrated solution for modeling, analysis, simulation, and control of industrial automated systems. This paper identifies certain criteria to compare LLDs and Petri nets in designing sequence controllers and responding to the changing control requirements. The comparison is performed through a practical system after introducing "real-time Petri nets" for Discrete-event control purposes. The results reported in this paper will help: (a) further establish Petri net based techniques for Discrete-event control of industrial automated systems; and (b) effectively convince industrial practitioners and researchers that it is worthy and timely to consider and promote the applications of Petri nets to their particular Discrete-event control problems. >
Grzegorz Klosowski - One of the best experts on this subject based on the ideXlab platform.
-
development of computer controlled material handling model by means of fuzzy logic and genetic algorithms
Neurocomputing, 2019Co-Authors: Arkadiusz Gola, Grzegorz KlosowskiAbstract:Abstract The aim of the study is to develop a unique approach to the problem of material handling control by means of artificial intelligence (computer intelligence) with respect to automated guided vehicle (AGV) path routing. In the analysed case the material handling system is fully integrated with IT tools and is considered under the constraint that the path cannot be changed during travel along a given loop, therefore, the path is predicted prior to every successive loop. The vector (ordered set) of stations requesting transportation service was determined by means of fuzzy logic, while the sequence of stations in a loop was optimised with genetic algorithms. The dispatch station can play the role of a switching station between the zones, where every AGV path loop begins and ends. This paper presents a system for both AGVs and semi-autonomous transportation vehicles where the human driver is informed of the route to follow. The subsequent verification of the developed model, by means of computer simulation, confirms that the proposed solution is effective. While the presented solution can be applied in a Discrete Manufacturing system, it can be considered as a part of the general Manufacturing concept.
-
application of fuzzy logic in assigning workers to production tasks
Distributed Computing and Artificial Intelligence, 2016Co-Authors: Grzegorz Klosowski, Arkadiusz Gola, Antoni świcAbstract:The paper demonstrates the concept of selecting workers for production tasks with the use of fuzzy logic. Mamdani-type fuzzy inference method was used to design a controller whose task was to aid the decision-making process. Fuzzy interference system converted a number of qualitative features into quantitative variables, which enabled calculating deviations and their comparison. Moreover, a simulation model of a Discrete Manufacturing system with an implemented fuzzy controller was developed. conducted simulation provided detailed data regarding the investigated selection process.
-
application of fuzzy logic controller for machine load balancing in Discrete Manufacturing system
Intelligent Data Engineering and Automated Learning, 2015Co-Authors: Grzegorz Klosowski, Arkadiusz Gola, Antoni świcAbstract:The paper presents a concept of control of Discrete Manufacturing system with the use of fuzzy logic. A controller based on the concept of Mamdani was developed. The primary function realized by the controller was the balancing of machine tool loads taking into account the criteria of minimisation of machining times and costs. Two models of analogous Manufacturing systems were developed, differing in the manner of assignment of production tasks to machine tools. Simulation experiments were conducted on both models and the results obtained were compared. In effect of the comparison of the results of both experiments it was demonstrated that better results were obtained in the system utilising the fuzzy inference system.