| 1. |
- Alexandre, Seuret, et al.
(author)
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Consensus of Double Integrator Multi-agents under Communication Delay
- 2009
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In: IFAC Proceedings Volumes (IFAC-PapersOnline). - : Elsevier BV. - 1474-6670. ; , s. 376-381
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Conference paper (peer-reviewed)abstract
- This paper deals with the consensus problem under network induced communication delays. It is well-known that introducing a delay generally leads to a reduce of the performance or to instability. Thus, investigating the impact of time-delays in the consensus problem is an important issue. Another important issue is to obtain an estimate of the convergence rate, which is not straightforward when delays appear in the network. In this paper, the agents are modelled as double integrator systems. It is assumed that each agent receives instantaneously its own output information but receives the information from its neighbors after a constant delay. A stability criterion is provided based on Lyapunov-Krasovskii techniques and is expressed in terms of LMI. An expression of the consensus equilibrium which depends on the delay and on the initial conditions taken in an interval is derived. The results are supported through several simulations for different network symmetric communication schemes.
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| 2. |
- Andreasson, Sven Arne, 1949
(author)
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A Recursive Framework for Manufacturing Control
- 2009
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In: 13th IFAC Symposium on Information Control Problems in Manufacturing, INCOM'09; Moscow; Russian Federation; 3 June 2009 through 5 June 2009. - 1474-6670. - 9783902661432 ; 13:1, s. 600-605
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Conference paper (peer-reviewed)abstract
- The CHAMP (Chalmers Architecture and Methodology for Flexible Production) system is a general control system for manufacturing that can be configured for arbitrary production. The same system can be used recursive at different levels of the production. The system consists of producers that can perform operations on products and movers that can move products between producers. Each product is described by a number of operations that are mapped to global operations in the database. Thus a flexible production can be designed only by defining the product recipes and the factory layout.
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| 3. |
- Barata, José, et al.
(author)
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Evolvable Assembly Systems : A Development Roadmap
- 2006
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In: IFAC Proceedings Volumes. - : Elsevier BV. - 1474-6670. - 9783902661043
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Conference paper (peer-reviewed)abstract
- A new paradigm, the Evolvable Assembly Systems (EAS), was recently proposed. This paradigm provides a complete new view on how assembly systems should be designed and developed. Because the control system is one of the key aspects for a successful implementation of EAS this paper proposes a development roadmap to pinpoint directions of research on how control systems should be developed. It is expected that with this information the industry can envision the potential benefits in terms of competitiveness of this approach; still, this paper is especially targeted to motivate researchers from self-organisation and distributed assembly systems to engage in this endeavour together. In particular, topics on self-organisation, emergence, dynamical systems, and distributed artificial intelligence can be the backbone of truly self-adapting assembly systems. In fact EAS seems to be a really demanding and grounded case-study for the referred research communities.
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| 4. |
- Bengtsson, Kristofer, 1979, et al.
(author)
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Aspect-Oriented Programming for Manufacturing Automation Control Systems
- 2009
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In: 13th IFAC Symposium on Information Control Problems in Manufacturing Technology, INCOM’09, Moscow, Russia. - 1474-6670. - 9783902661432 ; 13:PART 1, s. 668-673
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Conference paper (peer-reviewed)abstract
- The languages defined by the standard IEC 6-1131 for Programm\-able Logic Controllers (PLCs), have both benefits and drawbacks compared to object-oriented programming languages. For example, the current programming approach is good for maintaining the system, since it is easy to program and comprehend for a plant floor personal with limited programming experience. The main drawbacks are reusability, code dependability and flexibility. This paper proposes an aspect-oriented programming (AOP) approach as an alternative solution, which can keep the benefits and eliminate the drawbacks. AOP is an emerging programming methodology in computer science, which helps the programmer by separating different crosscutting concerns in the program. These crosscutting concerns and tangled behavior are especially important issues in PLC programming, which makes AOP a suitable approach. The paper describes how to adapt the AOP methodology into PLC program development and how it can benefit the control design process.
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| 5. |
- Binotto, Alécio Pedro Delazari, et al.
(author)
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Towards Dynamic Task Scheduling and Reconfiguration using an Aspect Oriented Approach applied on Real-time concerns of Industrial Systems
- 2009
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In: Elsevier IFAC Publications / IFAC Proceedings series. - Frankfurt : Elsevier. - 1474-6670. ; 13:PART 1, s. 1423-1428
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Journal article (peer-reviewed)abstract
- High performance computational platforms are required by industries that make use of automatic methods to manage modern machines, which are mostly controlled by high-performance specific hardware with processing capabilities. It usually works together with CPUs, forming a powerful execution platform. On an industrial production line, distinct tasks can be assigned to be processed by different machines depending on certain conditions and production parameters. However, these conditions can change at run-time influenced mainly by machine failure and maintenance, priorities changes, and possible new better task distribution. Therefore, self-adaptive computing is a potential paradigm as it can provide flexibility to explore the machine resources and improve performance on different execution scenarios of the production line. One approach is to explore scheduling and run-time task migration among machines’ hardware towards a balancing of tasks, aiming performance and production gain. This way, the monitoring of time requirements and its crosscutting behaviour play an important role for task (re)allocation decisions. This paper introduces the use of software aspect-oriented paradigms to perform machines’ monitoring and a self-rescheduling strategy of tasks to address nonfunctional timing constraints. As case study, tasks for a production line of aluminium ingots are designed. © 2009 IFAC.
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| 6. |
- Boström, Mathias, et al.
(author)
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Ion specific forces between charged self-assembled monolayersexplained by modified DLVO theory
- 2009
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In: Elsevier IFAC Publications / IFAC Proceedings series. - : Elsevier BV. - 1474-6670. ; 346:1-3, s. 11-15
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Journal article (peer-reviewed)abstract
- We recently investigated specific ion effects near a single charged self-assembled monolayer (SAM) in asalt solution by exploiting a modified Poisson–Boltzmann equation that accounts for both water profileand ion-surface potential profiles inferred from molecular dynamics simulations. In the present contributionwe extend this work to consider two charged SAMs interacting across different salt solution. Ourresults demonstrate one important reason why the double layer force between charged colloidal surfacesin electrolytes could be highly ion specific.
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| 7. |
- Dubinin, Victor N., et al.
(author)
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Refactoring of execution control charts in basic function blocks of the IEC 61499 standard
- 2009
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In: Elsevier IFAC Publications / IFAC Proceedings series. - 1474-6670. ; 13:1, s. 193-198
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Journal article (peer-reviewed)abstract
- This paper deals with refactoring of execution control charts of IEC 61499 basic function blocks as a means to improve the engineering support potential of the standard in development of industrial control applications. The main purpose of the refactoring is removal of arcs without event inputs and getting rid of potential deadlock states. The ECC refactoring is implemented as a set of graph transformation rules. A prototype has been implemented using the AGG software tool
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| 8. |
- Harlin, Ulrika, et al.
(author)
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Towards efficient automation implementation
- 2006
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In: IFAC Proc. Vol. (IFAC-PapersOnline). - : IFAC Secretariat. - 9783902661050 ; , s. 71-76
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Conference paper (peer-reviewed)abstract
- New technology may contribute to several advantages, but shop-floor requirements need to be considered to achieve expected benefits. Results are based on an industrial study, where new machinery was implemented. Identified critical aspects include transfer of new knowledge related to the modified production system, scenario building, and situation awareness both within and outside the company. These critical aspects may also be relevant during planned changeovers between different levels of automation. An initial model is proposed, describing effects of varying the levels of automation and the potential of automation if critical aspects are sufficiently regarded.
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| 9. |
- Herreros, Alberto, et al.
(author)
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Analysis of Changes in the Beat-to-Beat P-Wave Morphology Using Clustering Techniques
- 2008
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In: Proceedings of the 17th World Congress Proceedings of the 17th World Congress of The International Federation of Automatic Control. - 1474-6670. - 9783902661005 ; 41:1, s. 5215-5220
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Conference paper (peer-reviewed)abstract
- Several pathologies related to the atrial electrical activity can be detected in the electrocardiogram P-wave. A study on the beat-to-beat P-wave morphology changes of 89 ECG signals is performed in this article. An algorithm based on the embedding space techniques has been used to extract the P-wave information of the ECG. The P-waves obtained in several of these ECGs exhibit intermittent morphology changes. The morphologies have been classified by using the K-means clustering algorithm. The mechanism behind different P-wave morphologies and its possible pathophysiological importance remains to be clarified.
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| 10. |
- Jansson, Magnus
(author)
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A New Subspace Identification Method for Open and Closed Loop Data
- 2005
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In: IFAC Proceedings Volumes (IFAC-PapersOnline). - : Elsevier BV. - 1474-6670. - 008045108X - 9780080451084 ; , s. 500-505
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Conference paper (peer-reviewed)abstract
- Abstract: Subspace methods have emerged as useful tools for the identification of lineartime invariant discrete time systems. Most of the methods have been developed for theopen loop case to avoid difficulties with data correlations due to the feedback. This paperextends some recent ideas for developing subspace methods that can perform well on datacollected both in open and closed loop conditions. Here, a method that aims at minimizingthe prediction errors in several approximate steps is proposed. The steps involve usingconstrained least squares estimation on models with different degrees of structure such asblock-toeplitz, and reduced rank matrices. The statistical estimation performance of themethod is shown to be competitive to existing subspace methods in a simulation example.
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