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Emerging Technologies and Factory Automation, 1994. ETFA '94., IEEE Symposium on

Date 6-10 Nov. 1994

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  • ETFA '94. 1994 IEEE Symposium on Emerging Technologies and Factory Automation. (SEIKEN) Symposium) - Novel Disciplines for the Next Century - Proceedings

    Publication Year: 1994
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    Freely Available from IEEE
  • Genetic algorithm with age structure and its application to self-organizing manufacturing system

    Publication Year: 1994 , Page(s): 472 - 477
    Cited by:  Papers (15)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (381 KB)  

    The genetic algorithm has recently been demonstrated its effectiveness in optimization issues, but it has two major problems: a premature local convergence and a bias by the genetic drift. In order to solve these problems, we propose a new genetic algorithm with an age structure of a continuous generation model. The new genetic algorithm is applied to a self-organizing manufacturing system-a process which self-organizes to other processes in a flexible manufacturing system environment. The effectiveness of the genetic algorithm with age structure is demonstrated through numerical simulations of the reorganization of a press machining line as an example of the self-organizing manufacturing system.<> View full abstract»

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  • Motion planning for a redundant manipulator by genetic algorithm

    Publication Year: 1994 , Page(s): 466 - 471
    Cited by:  Papers (4)
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    A motion planning method is proposed for cutting a three dimensional workpiece by a redundant manipulator with six degrees of freedom. The method applies a genetic algorithm to optimize the rotational angles of the end-effector on a path. For a fitness function, an evaluation function is defined based on references from skilled operators. Using the proposed method the operator only has to determine a path without considering the redundant parameters. Simulations show the effectiveness of the proposed method.<> View full abstract»

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  • A new approach to genetic based machine learning for efficient improvement of local portions of chromosomes

    Publication Year: 1994 , Page(s): 458 - 465
    Cited by:  Papers (1)
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    This paper presents a new approach to genetic based machine learning (GBML). The new approach is based on an imaginary mechanism of evolution. The authors call this new approach the Nagoya approach. The Nagoya approach is efficient in improving local portions of chromosomes. A simulation of simple computer graphics using the new approach is done. An obstacle avoidance of mobile robot is also simulated using the Nagoya approach and complex fuzzy rules are found.<> View full abstract»

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  • Co-evolving genetic algorithm with filtered evaluation function

    Publication Year: 1994 , Page(s): 454 - 457
    Cited by:  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (349 KB)  

    As a function optimizer or a search procedure, genetic algorithms (GAs) are very powerful and have many advantages. Fundamental research concerning the internal behavior of GAs has highlighted their limitations as regards the search performances, called GA-hard problems. The reason for these difficulties seems to be that GAs generate insufficient strategies for the convergence of populations. To overcome this problem an extended GA, which we name the filtering-GA, that adopts the concept of co-evolution, is proposed. It has two GAs, and they influence each other through their evaluation process.<> View full abstract»

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  • The immune mechanism, adaptation, learning for the multi agent system

    Publication Year: 1994 , Page(s): 446 - 453
    Cited by:  Papers (7)
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    In this research, we present an adaptation mechanism for the multi-agent system. We applied the biological "immune system" to our new algorithms. The immune system works for the "host defense mechanism" and the "homcostasis maintenance mechanism" against foreign enemy or the internal abnormality.<> View full abstract»

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  • Learning of decision regions based on the genetic algorithm

    Publication Year: 1994 , Page(s): 438 - 445
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (551 KB)  

    A method for nonparametric (distribution-free) learning of complex decision regions in n-dimensional pattern space is introduced. Arbitrary n-dimensional decision regions are approximated by the union of a finite number of basic shapes. The primary examples introduced in this paper are parallelepipeds. By explicitly parameterizing these shapes, the decision region can be determined by estimating the parameters associated with each shape. A structural random search type algorithm called the genetic algorithm is modified to estimate these parameters. Modifications include the parent selection scheme and a new operator called "extinction and immigration". Two complex decision regions are examined in detail: one is a linearly inseparable, nonconvex and disconnected type; and the other is linearly inseparable, nonconvex and connected type. The scheme is highly resilient to misclassification errors. The number of the parameters to be estimated only grows linearly with the dimension of the pattern space for simple version of the scheme.<> View full abstract»

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  • Evaluating the complexity of Petri nets and ladder logic diagrams for sequence controllers design in flexible automation

    Publication Year: 1994 , Page(s): 428 - 435
    Cited by:  Papers (3)
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    This paper presents a methodology to evaluate the complexity of Petri nets (PNs) and ladder logic diagrams (LLDs) for sequence controllers design. Complexity of a design is characterized by the number of basic elements used to model the given control logic. More specifically, this paper presents analytical formulas to estimate the number of basic elements to model certain building blocks of logic modeling when PN and LLD are used. Also, by presenting a methodology to use these analytical formulas, this paper precludes the need for physically building the controllers by either PN or LLD for the comparison of their graphical complexity. The results are demonstrated by considering two examples of sequence controllers. Finally, the limitations of the present work are presented along with possible extensions for future research.<> View full abstract»

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  • Compositional Petri net environment

    Publication Year: 1994 , Page(s): 420 - 427
    Cited by:  Papers (2)
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    This paper addresses the problem of application Petri nets to real-world parallel and distributed systems of industrial size. It is pointed out that in many cases a well-known hierarchy/refinement technique does not work perfectly. We suggest another solution based on an algebraic approach to Petri net representation. Two levels of compositionality are introduced. The first one, an algebraic level offers a designer a set of net operations which allow the user to to build complex Petri nets from simpler ones; these include the operations of sequential and parallel composition, choice, iteration, and disruption defined on the top of two auxiliary operations of synchronization. The second architectural level allows the user to manipulate with Petri net entities, where each entity is defined as a Petri net equipped with access points. Operations of entity composition through the access points are introduced. The suggested technique is demonstrated on three-level Petri net editor comprising basic, algebraic and architectural editors.<> View full abstract»

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  • Self-checking implementation of Boolean interpreted Petri nets

    Publication Year: 1994 , Page(s): 414 - 419
    Cited by:  Papers (2)
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    This paper presents a technique of constructing a self-checking synchronous implementation of a Boolean interpreted Petri net. The validated Petri net specification is modeled with a circuit that automatically detects faults visible at Petri net level. The so called direct approach is used in modeling Petri nets by hardware. The faults that can be checked at hardware level manifest themselves at Petri net level through entering markings that do not belong to the set of allowable ones. These markings violate certain P-invariant assertions. A hardware framework based on self-checking checkers that allows detecting the violation of the P-invariant assertion is proposed.<> View full abstract»

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  • Verification of asynchronous circuits by Petri net unfoldings

    Publication Year: 1994 , Page(s): 404 - 413
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (924 KB)  

    In this paper we use the interpreted Petri nets (signal transition graph (STG) model) for a verification of asynchronous circuits. The main property in the analysis is the speed-independence of a circuit, i.e. the independence of circuit functioning from the delays of gates. The idea of analysis is based on the PN unfolding into an occurrence net. The improved method of unfolding is suggested, in which the size of the obtained description is always not larger than the size of a corresponding state graph. In terms of unfolding, the necessary and sufficient conditions for speed-independence are formulated. The algorithms of these conditions analysis are polynomial from the size of STG unfolding. The efficiency of the suggested algorithms is considered on the set of benchmarks.<> View full abstract»

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  • Proposal for a generic prototyping approach

    Publication Year: 1994 , Page(s): 396 - 403
    Cited by:  Papers (1)
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    The procedure we define is parametrized by: the input description formalism which can be any structured and/or hierarchical representation; and the programming language used to describe the prototype of a system. Our prototyping procedure involves three description levels: 1) the input formalism is a semi-formal description that only allows syntactic checks (completeness and coherence of the specification); 2) a formal description of the system obtained by translation of the semi-formal description and is useful for validation of the system (Petri nets is used to express this specification level); and 3) an executable description, expressed by means of a programming language and obtained by code generation from either the Petri net level or the semi-formal description. The prototyping procedure we present in this paper is partially implemented.<> View full abstract»

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  • New results in systematic construction of functional abstractions of Petri net models of flexible manufacturing systems

    Publication Year: 1994 , Page(s): 388 - 394
    Cited by:  Papers (1)
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    The use of generic models in the synthesis of FMS systems, which allows for rapid modelling and analysis, does not ease the verification task difficulty. Even though generic modules can be verified separately, the verification of the interconnections between modules requires the whole model to be considered. A potential solution is to replace the generic modules with their functional abstractions which realise the external functional behaviour of these modules. The number of places and transitions involved in realizing the required functionality is, typically, a fraction of that used to represent complete components. This reduces the complexity of the components of the modelled system, and thus the complexity of the verification model. The verification task can then focus on the correctness of the interfaces, rather then on the internal nature of the components. In this paper, for a class of Petri net models, which can be used to represent the primary components of the AGV based FMS systems, a method that allows one to systematically construct functional abstractions is presented.<> View full abstract»

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  • On the application of coloured Petri nets to computer aided assembly planning

    Publication Year: 1994 , Page(s): 381 - 387
    Cited by:  Papers (1)
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    The problem of assembly process planning is particularly critical for the automation and integration of production, due to the combinatorial complexity and the requirement of both flexibility and productivity. Several planning methodologies and techniques have been proposed in the literature, using an approach limited to specific product typologies and structures. Some of them are more suitable for dedicated automated assembly and assembly lines than for flexible automated assembly and flexible assembly systems (FAS) and assembly job shops. Due to the time-based competition, both cycle time reduction and task parallelism increase require a technique suitable to the generation of assembly plans with flexibility, efficiency and parallelism. The paper presents and discusses the application of coloured Petri nets (CPN) and timed coloured Petri nets (TCPN) to the computer aided assembly planning (CAAP) problem, both to online and off-line planning, and presents a prototype CAAP architecture, that is implemented and validated by means of the assembly planning of an industrial product.<> View full abstract»

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  • A Petri net approach to modeling and performance analysis of Fiber Data Distributed Interface (FDDI) network

    Publication Year: 1994 , Page(s): 373 - 380
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    This paper presents a Petri net approach to modeling and performance analysis of the Fiber Distributed Data Interface (FDDI) network. The service type described in the "Timed Token Rotation" protocol, supporting both synchronous and asynchronous traffic, is modeled using stochastic Petri nets, and its performance is conducted for both symmetric/asymmetric cases. In order to deal with large networks without creating very long Markov chains, a modified N station network is introduced. The correlation between the voice and data throughput rate, and the parameters of the system, such as the network load and the network speed are investigated.<> View full abstract»

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  • Analysis of function charts for control systems using Petri nets

    Publication Year: 1994 , Page(s): 365 - 372
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (677 KB)  

    As opposed to the widely investigated continuous control, this paper concentrates on event-related control modelling and validation. In this case, the process and related process control can be described by steps and transitions, which can be represented very concisely by function charts for control systems model (Grafcet). As it is difficult to validate the Grafcet model, we propose to transform a Grafcet in Petri net model that is a rigid mathematical tool, and which can be used for a very general approach to event-related process control in specification, checking, debugging, and evaluating performance of any given process control system.<> View full abstract»

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  • From the Petri net model to real time control: bases of a development package

    Publication Year: 1994 , Page(s): 360 - 364
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    Any discrete system with a behavior which lends itself to a graphical representation can be a candidate for a Petri net modelization. In this way the Petri net model can be adopted more and more in process control, especially within the framework of factory automation and flexible manufacturing systems, for low level control as well as for coordination and monitoring levels. Based on a high level description of such applications, and based on an extended timed Petri net formalization, this paper presents a generic token-player algorithm and the associated processor architecture. Then the functional specifications of a development package are described. This package can easily fit to IBM-PC and compatibles.<> View full abstract»

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  • Net-based cooperative control for autonomous distributed systems

    Publication Year: 1994 , Page(s): 350 - 357
    Cited by:  Papers (4)  |  Patents (1)
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    This paper discusses an autonomous distributed control system to overcome the deficiencies in robustness against failures, flexibility, and set-up speed of conventional centralized control systems. In order to realize the autonomous distributed control for intelligent manufacturing systems, we propose a model and a method to realize this model. The model consists of numerous autonomous agents and a field where these agents can exchange information for cooperation. Also, we discuss the importance of the protocol needed for cooperation of the individual agents. The autonomous distributed control system model was used in the study of an automated guided vehicle (AGV) system. Here, numerical simulations using Petri net model were conducted to evaluate the effectiveness of our model.<> View full abstract»

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  • Automated digitization and geometric modelling of refurbished components for deburring

    Publication Year: 1994 , Page(s): 345 - 349
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    A scheme is proposed for the automated edge deburring of refurbished components with intricate geometries. An adaptive routine is presented that gathers a small number of digitized positional data points to construct a differential geometric model with a prescribed accuracy. The affine surface connections, from whence one calculates the Gaussian curvature, are computed and used to determine an edge-profile for the deformed component. The edge-profile defines a tool-path for deburring.<> View full abstract»

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  • Fieldbus and CNC architecture: towards a CNC software factory

    Publication Year: 1994 , Page(s): 338 - 344
    Cited by:  Papers (1)
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    The paper explains the needs for introducing fieldbuses in machine-tools, a design choice whose economic benefits may not be apparent. We first explain the general trends of the factory of the future and its impact on the machine-tools characteristics and hence on computerised numerical controllers (CNC). We then show how the requirements can be fulfilled and the resulting architecture that opens the road to CNC software factory. One distinctive aspect of this architecture is the concept services, or vertical reusable components. Distributed interpolation that we briefly describe play an important role in designing good components. We describe the different architectural levels inside the CNC and we explain the reasons why a fieldbus should be introduced to link field devices to the CNC and at which level. Finally, we present an example of fieldbus use in a milling machine and the resulting performances.<> View full abstract»

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  • Planning-based visual programming for sequence control

    Publication Year: 1994 , Page(s): 330 - 337
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    This paper describes the planning-based visual programming for sequence control in the prototype system: VIPS/S-SFCD (Visual Programming System for Sequence control program Specification Design). VIPS/S-SFCD features: 1) a rehearsal-based visual programming technique in which designers specify the goal states of machines using graphical representations, and 2) a planning method that infers machine actions and generates the control program specifications. This planning is based on the state space model and the concept of scope for efficient searches. The advantages of using VIPS/S-SFCD include: 1) the designers can reduce errors in writing the specifications because they can easily understand the actions and the states of the machines; 2) they can improve the reliability of the specifications because VIPS/S-SFCD generates the appropriate parts of the specifications by planning; and 3) they also can reduce the design time of the specifications because high level instructions are used that closely reflect their thought process.<> View full abstract»

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  • Tele-existence robotic system with autonomous mobility

    Publication Year: 1994 , Page(s): 319 - 329
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    The semi-autonomous, human-cooperative system is complemented by operator's maneuvering to compensate for the level of autonomy missing in the robot. Because the robot is human-cooperative, the human interface must be designed to optimize interaction. It is emphasized that a human interface in the broad definition, tele-existence in narrow definition, is essential to complement the semi-autonomous robotics. The spread of such robotic systems is dependent on tele-existence technology, allowing remote operation by untrained operators, and offering excellent "live" feel. This paper clarifies the development concept of tele-existence robotic system as a pioneer for robots in nonmanufacturing application fields under quasi- and unstructured environment, and outlines the application sectors. The key technologies for tele-existence systems are described.<> View full abstract»

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  • Multi sensory system for the recovery of 3D structure; industrial applications

    Publication Year: 1994 , Page(s): 314 - 318
    Cited by:  Papers (1)
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    The importance of 3D data acquisition is widely recognized in robotics field. One approach is to measure the distance on the basis of triangulation principle from the disparity of two images. This stereo method has a difficult problem of finding the correspondence of features between two images. This correspondence problem can be solved geometrically by adding one more camera (trinocular vision). This paper presents the application of this method. The two industrial examples presented here need a good precision in 3D representation, so epipolar constraints and camera calibration are studied in details.<> View full abstract»

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  • MicroMMS: a compact abstract syntax for MMS

    Publication Year: 1994 , Page(s): 304 - 311
    Cited by:  Patents (1)
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    MMS (Manufacturing Message Specification) was initially designed for interconnection of industrial devices in manufacturing and process control applications. MMS can also be applied to new areas such as building automation, field buses and remote meter reading. Such applications have much stronger constraints concerning the available processing power and memory. The use of an MMS specified in ASN.1 and its associated Basic Encoding Rules (BER) can be questioned for such applications. ASN.1 and BER very often lead to long messages (PDUs) that require a time consuming encoding or decoding process. The purpose of this study is to define a new abstract syntax for MMS that offers the same functionality as the standard MMS abstract syntax but that leads to shorter PDUs. The principle adopted is that the essence of MMS is not in its abstract syntax but in its service definition, namely the set of MMS objects, services and parameters defined in ISO/IEC 9506-1.<> View full abstract»

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  • Fault tolerance techniques integrating MMS and ISIS

    Publication Year: 1994 , Page(s): 297 - 303
    Cited by:  Papers (1)
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    Fault tolerance and interoperability in a heterogeneous environment are two important concerns in distributed industrial applications. The manufacturing message specification (MMS) was designed to standardize and facilitate the remote control and monitoring of industrial devices made by different vendors. Software such as the ISIS Distributed Toolkit makes the task of providing fault tolerance easier for the application programmer. In this paper, we study a realistic, industrial scenario that has been supplied to us by an actual car manufacturing company. We make use of MMS to implement the scenario. Then, we analyze some methods of adding fault tolerance into the scenario by using the ISIS toolkit, as well as other fault-tolerant algorithms on top of MMS. We discuss the results of an actual implementation of these methods and show how the scenario requirements have been satisfied.<> View full abstract»

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