Developing AGVS Petri net control models from flowpath nets

Hsieh, Sun-Yuan; Kang, Ming-Yuan

doi:10.1016/s0278-6125(98)80072-1

Cited by 14 publications

(8 citation statements)

References 16 publications

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“…Zeng et al (1991) use Petri nets to detect conflicts in AGV systems. A Petri-net approach seems to be a promising direction to detect and prevent conflicts in AGV systems (Zeng et al, 1991;Hsieh and Kang, 1998).…”

Section: Forward Sensingmentioning

confidence: 99%

A review of design and control of automated guided vehicle systems

LeAnh

Koster

2006

European Journal of Operational Research

370

120

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This paper presents a review on design and control of automated guided vehicle systems. We address most key related issues including guide-path design, estimating the number of vehicles, vehicle scheduling, idle-vehicle positioning, battery management, vehicle routing, and conflict resolution. We discuss and classify important models and results from key publications in literature on automated guided vehicle systems, including often-neglected areas, such as idlevehicle positioning and battery management. In addition, we propose a decision framework for design and implementation of automated guided vehicle systems, and suggest some fruitful research directions. 5001-6182 Business AbstractThis paper presents a review on design and control of automated guided vehicle systems. We address most key related issues including guide-path design, estimating the number of vehicles, vehicle scheduling, idle-vehicle positioning, battery management, vehicle routing, and conflict resolution. We discuss and classify important models and results from key publications in literature on automated guided vehicle systems, including often-neglected areas, such as idle-vehicle positioning and battery management. In addition, we propose a decision framework for design and implementation of automated guided vehicle systems, and suggest some fruitful research directions.

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Section: Forward Sensingmentioning

confidence: 99%

A review of design and control of automated guided vehicle systems

LeAnh

Koster

2006

European Journal of Operational Research

370

120

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“…Literature can be broadly classified following the same hierarchical schema used for the control system. Supervisory control problems largely focus on discrete event modeling tools such as PNs [1], [10], [11], or discrete event simulation [17], [20], [31]. Operational issues have also been extensively considered.…”

Section: A Literature Surveymentioning

confidence: 99%

“…Similarly, we can define the area input vector (9) the area output vector (10) and the area logical vector (11) Vectors , , and , as well as many other variables introduced in the model, have a dynamic size depending on the number of currently active MOs. In particular, at each time a new SKU enters (or exits) the area, the vectors are resized accordingly, introducing new elements with appropriate values (e.g., each time a new SKU enters the area and issues a MO, the vector is updated adding a new element set to "1").…”

Section: A Discrete Event Model Of a Single Areamentioning

confidence: 99%

“…As a consequence, issues pertaining to these levels are often tackled separately with different modeling and decision tools. In general, low level control issues are dealt with discrete event methods such as Petri nets (PNs) (e.g., [10], [11], [38]). These works generally focus on sequential issues (deadlock, blocking or collision avoidance) and often disregard the decisional aspects that influence performances on an operational level.…”

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confidence: 99%

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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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“…Raju and Chetty and Yim and Linn developed PN based models to simulate AGV systems in FMSs. Hsieh and Kang presented a control‐based PN modeling method that translates a high‐level AGV system flowpath net into a low‐level on/off control model systematically. The relation between a high‐level AGV system flowpath net and its corresponding low‐level control net was defined uniquely by introducing certain I/O control functions and station control macros.…”

Section: Introductionmentioning

confidence: 99%

Programmable‐logical‐controllers Synthesis for Automated‐guided‐vehicle Systems Using Ordinary Petri Nets

Luo¹,

Ni²

2014

Asian Journal of Control

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An ordinary Petri‐net (PN) based approach is proposed to design the programmable logical controller (PLC) for preventing collisions between vehicles in an automated guided vehicles (AGV) system. First, method is proposed to model an AGV system as an ordinary PN, called the plant PN. Second, for collision prevention in an AGV system, module control methods are proposed to design the PN supervisor (the closed‐loop PN) by augmenting the plant PN. In detail, three modules are defined the line, divide, and merge modules, in the plant PN, and the control module methods are presented for each of these three modules. As a result, the closed‐loop PN of an AGV system is obtained and can be analyzed using the PN theory. Finally, method is proposed to translate a closed‐loop PN into a ladder diagram. Consequently, the PN supervisor is implemented by a PLC using these proposed methods. A laboratory AGV system is used to illustrate this approach.

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Developing AGVS Petri net control models from flowpath nets

Cited by 14 publications

References 16 publications

A review of design and control of automated guided vehicle systems

A review of design and control of automated guided vehicle systems

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

Programmable‐logical‐controllers Synthesis for Automated‐guided‐vehicle Systems Using Ordinary Petri Nets

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