Analysis of Deadlock and Circular Waits Using a Matrix Model for Flexible Manufacturing Systems

Lewis, Frank L.; Gürel, A.; Bogdan, Stjepan; Doganalp, Alper; Păstrăvanu, Octavian

doi:10.1016/s0005-1098(98)00048-x

Cited by 93 publications

(38 citation statements)

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“…Una espera circular simple (ECs) se denota como (r i →r j →r k →r p →r i ), donde los recursos necesarios para la espera deben ser al menos dos (ver Lewis, Gurel, Bogdan, Doganalp y Pastravanu, 1998). Para construir una política que utiliza las esperas circulares, se hace referencia a los teoremas propuestos por Huang et al (1996), Huang, Lewis y Tacconi (1996) y Lewis et al (1998), en donde se establece el concepto de sifones críti-cos (Sc) y se indica que limitando las tareas del sifón, se evita el bloqueo. A continuación los teoremas:…”

Section: Controlador Basado En Matricesunclassified

Diseño del programa de control para una celda de manufactura flexible didáctica

Murillo-Soto¹

2014

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Una forma alternativa de programar el controlador de una Celda de Manufactura Flexible (CMF) es utilizar el enfoque propuesto en Huang, Pastravanu y Gurel (1995), con la teoría de Aproximación Basada en Matrices (ABM) para sistemas de eventos discretos (DE). Esta teoría se diseñó para su implementación en computadores industriales en las cuales la ejecución de operaciones matriciales binarias en tiempo real no representa problema alguno, sin embargo, la implementación de dichas operaciones en controladores programables (PLC) comerciales no se puede realizar en forma directa ya que la mayoría de PLC se programan mediante lenguajes gráficos, como el llamado Lógica en Escalera (Ladder Logic Diagram, LLD). Dicha restricción provoca que este poderoso enfoque de programación de DE excluya la mayoría de autómatas programables de uso comercial. El presente trabajo describe la interpretación de la teoría ABM con la finalidad de implementarla en un PLC comercial. El programa de control diseñado se probó con tres políticas de producción, en una celda de manufactura flexible multireentrante (MRF) ubicada en el Instituto Tecnológico de Costa Rica; el objeto de las pruebas fue observar el rendimiento de la celda de manufactura ante distintas políticas de despacho en la producción.

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Section: Controlador Basado En Matricesunclassified

Diseño del programa de control para una celda de manufactura flexible didáctica

Murillo-Soto¹

2014

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“…It also provides a complete mathematical description of discrete event systems that can be used for the purpose of computer simulations. The matrix formulation suits well to implement deadlock avoidance policies [22], high-level planners, such as HTN planners [9], and dynamic resource assignment algorithms [8].…”

Section: A Literature Surveymentioning

confidence: 99%

“…Consequently, all the vectors and matrices related to variables associated to MOs can be obtained by simply stacking or concatenating the vectors or matrices defined for the individual areas. For instance, we can define the warehouse task vector (22) the warehouse input vector (23) the warehouse output vector (24) the warehouse logical vector (25) etc.…”

Section: Warehouse Global Modelmentioning

confidence: 99%

Integrated Supervisory and Operational Control of a Warehouse With a Matrix-Based Approach

Giordano

Zhang

Naso

et al. 2008

IEEE Trans. Automat. Sci. Eng.

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Abstract-This paper considers a matrix-based discrete event control approach for a warehouse. The control system is organized in two modules: a dynamic model and a controller. The model provides a complete description of the discrete event dynamics of the warehouse, and is used as a means to track the stock-keeping units, and identify and inhibit control actions that violate system's constraints. The controller has several functions. At the supervisory level, it is in charge of inhibiting operations that may lead to deadlocks, commanding the actual start of the task, and the release of the resources once a task is completed. At the operational level, it is in charge of performing decisions regarding the order in which allowable tasks waiting for service should be performed. All the modules are implemented using the same matrix-based formalism, and thus integrated with each other. The main advantages of the approach are the inherent modularity (the matrix-based control is obtained by assembling individual atomic components), and the integration between the various modules, which permits a better overall resource utilization. Simulation examples describing an actual industrial warehouse are finally provided to emphasize the main advantages of the proposed approach.Note to Practitioners-This paper illustrates the application of a discrete-event modeling and control framework based on a matrix notation to an automated warehouse. The material handling equipment must continuously transfer stock-keeping units between various buffers using a network of interconnected rail guided vehicles. Since transfer requests are issued at random times, the role of the control system is extremely challenging, as it must handle low level tasks (synchronizing hardware, avoiding conflicts) and high level ones (allocating the rail guided vehicles efficiently to avoid congestions and long service times). Giving a complete mathematical characterization of such a system is challenging, due to its inherently turbulent and discrete-event nature. The proposed original approach allows one to attack the problem from a modular, divide-and-conquer perspective. In fact, the complete model of the system is achieved by a sequence of simple modeling steps, starting from the description of the atomic components of the system, and progressively specifying constraints, objectives and control rules to obtain a complete characterization of the entire system within a unified formalism based on binary matrices. Since the final model integrates supervisory and operational functions, it permits to perform the allocation of rail guided vehicles more effectively, using in- formation that is generally unavailable to the dispatching modules. Examples and numerical results based on the equipment actually operating in the warehouse are also provided to illustrate the potential of the approach.

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“…This makes the formal analysis of the model possible, thereby verifying the behavior of the underlying system, e.g., precedence relations among events, concurrent operations, appropriate synchronization, freedom from deadlock, repetitive activities, and mutual exclusion of shared resources. [3][4][5] The ability of PNs to verify formally the model is especially important for the real-time safety-critical automated systems.…”

Section: Petri Netmentioning

confidence: 99%

Generalized state equation of Petri Nets with priority

Lee

Han

Lee

2003

Int. J. Intell. Syst.

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This article presents a new way of generating a generalized state equation that is useful for analyzing the token flow of the Petri Net (PN) with priority. The transition values in the firing vector as used in the conventional state equation are replaced with transition variables, which are generated by multiplying a series of firing condition functions taking the weighted inhibitor arc into account. The actual value of a transition variable is determined by taking priority and the present marking into account. The proposed state equation generalizes the conventional one by using the transition variable form and by containing the formulation of priority. Given the initial marking, the subsequent marking evolution can be determined successively from the generalized state equation as the simultaneous firings occur. A PN with deadlock is analyzed as an example to establish the validity of the generalized state equation.

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Analysis of Deadlock and Circular Waits Using a Matrix Model for Flexible Manufacturing Systems

Cited by 93 publications

References 0 publications

Diseño del programa de control para una celda de manufactura flexible didáctica

Diseño del programa de control para una celda de manufactura flexible didáctica

Integrated Supervisory and Operational Control of a Warehouse With a Matrix-Based Approach

Generalized state equation of Petri Nets with priority

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