Browsing by Author "Silva, A. Ferreira da"
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- An IEC 61499 Replication for Distributed Control ApplicationsPublication . Santos, Adriano A; Silva, A. Ferreira da; Sousa, Mário de; Magalhaes, PessoaModern industrial environment control programs are distributed among several devices. The IEC 61499 standard defines function blocks with which distributed control applications may be developed, and how these are interpreted and executed. Its functionality and the inherent support for dynamic reconfiguration provide the required infrastructure for Industry 4.0 and industrial IoT applications. However, by their distributed nature new challenges are posed, especially about how modes of failure are handled. To avoid system malfunctions and breakdowns due to partial failures, the authors propose a new framework were the concept of replication can be applied maintaining internal state synchronised. This paper presents an example of how the replication framework on the FORTE IEC 6499 execution platform can be developed and voting strategies, along with the results obtained in the implementation with the standard communication SIFBs available on the Eclipse 4diacTM.
- Determinism of Replicated Distributed Systems–A Timing Analysis of the Data Passing ProcessPublication . Santos, Adriano A; Silva, A. Ferreira da; Magalhães, António; Sousa, Mário deFault-tolerant applications are created by replicating the software or hardware component in a distributed system. Communications are normally carried out over an Ethernet network to interact with the distributed/replicated system, ensuring atomic multicast properties. However, there are situations in which it is not possible to guarantee that the replicas process the same data set in the same order. This occurrence will lead to inconsistency in the data set produced by the replicas, that is, the determinism of the applications is not guaranteed. To avoid these inconsistencies, a set of Function Blocks has been proposed which, taking advantage of the inherent properties of Ethernet, can guarantee the synchronism and determinism of the real-time application. This paper presents this set of Function Blocks, focusing our action on the development of reliable distributed systems in real-time. This demonstrates that the developed Function Blocks can guarantee the determinism of the replicas and, as such, that the messages sent are processed, in the same order and according to the time in which they were made available.
- Reducing Volume to Increase Capacity—Measures to Reduce Transport Energy for Recyclable Waste CollectionPublication . Santos, Adriano A; Silva, A. Ferreira da; Gouveia, António; Felgueiras, Carlos; Caetano, NídiaThe production of municipal waste is increasing all over the world. Although a significant part of the waste is collected as commingled waste, much of it is recyclable if disposed of properly. Thus, separate deposition and collection plays an extremely important role today, more than ever, not only in terms of preventing pollution but also from the point of view of recycling as a driver of circular economy and of efficient use of resources. This work is focused on the development of compaction equipment to be applied to containers, which allows a more efficient approach to the process of collecting waste for recycling. As a management option, recycling depends on collective behavior which is based on individual acts. Therefore, individual use of plastic/metal compaction systems can help meet recycling targets, even as a complement to conventional bins. Thus, herein a proposal is presented for a plastic/metal collection station with a built-in compaction element that allows for the compacting of the separated waste, individually, in an easily accessible drawer. Sorting and compacting waste before collection will result in a reduction of the number of collection/transport stops, which will also translate into higher energy efficiency, cost savings, optimization of the transported tons/km ratio, and profitability.
- Reliability of Replicated Distributed Control Systems Applications Based on IEC 61499Publication . Santos, Adriano A; Silva, A. Ferreira da; Magalhães, António; de Sousa, MárioThe use of industrial and domestic equipment is increasingly dependent on computerized control systems. This evolution awakens in the users the feeling of reliability of the equipment, which is not always achieved. However, system designers implement fault-tolerance methodologies and attributes to eliminate faults or any error in the system. Industrially, the increase in system reliability is achieved by the redundancy of control systems based on the replication of conventional and centralized programmable logic controllers. In distributed systems, reliability is achieved by replicating and distributing the most critical elements, leaving a single copy of the remaining components. On the other hand, given the nature of the distributed systems, it will also be necessary to ensure that the data set received by each of the replicas has the same order. Thus, any change in the order and data set received will result in different results, in each of the replicas, which may manifest in erroneous behavior. In this paper, the interactions and the erroneous behavior of the replicas are explained, depending on the data set received, in a fault tolerant distributed system. Its tendency, behavior and possible influences on reliability are presented, considering the failure rate and availability based on the mean time to failure.
- Simulation and Control of a Cyber-Physical System under IEC 61499 StandardPublication . Santos, Adriano A; Silva, A. Ferreira daIEC 61499 standard provides an architecture for control systems using function blocks (FB), languages, and semantics. These devices can be interconnected and communicate with each other. Each device contains several resources and algorithms with a communication FB at the end, which can be created, configured, and deleted without affecting other resources. Physical element can be represented by a FB that encapsulates the functionality (data/events, process, return data/events) in a single module that can be reused and combined. This work presents a simplified implementation of a modular control system using a low-cost device. In the prototyping of the application, we use 4diac to control, model and validate the implementation of the system on a programmable logic controller. It is proved that this approach can be used to model and simulate a cyber-physical system as a single element or in a networked combination. The control models provide a reusable FB design.
- Simulation of Cyber-Physical Intelligent Mechatronic Component Behavior Using Timed Automata ApproachPublication . Santos, Adriano A; Silva, A. Ferreira da; Pereira, FilipeThis article presents a new approach for the simulation of Cyber-Physical Intelligent Mechatronics Components using process evolution based on the timed approach. The purpose of this article is to address the issue of implementing the Intelligent Mechatronics Components control from the bench point of view and its simulation considering a virtual system composed of a single programmable logic controller and a touchscreen. For this, we intend to develop a systematic approach that allows modeling physical cybernetic systems based on timed automata. The proposed methodology makes it possible to define, in a systematic way, the formalisms and tools to model the controller and the respective plant. These global models can be used to simulate and validate systems based on development tools like UPPAAL software, so the proposed approach intends to systematically define their development. To present and explain the proposed methodology, a Modular Production System was used to distribute objects as a physical element. A virtual platform based on the Simatic TIA Portal was developed to monitor and validate the methodology.
- Sustainable Development Action Plan at ISEP - From Concept to Engineering PracticePublication . Cardoso, M.; Castanheira, Luís; Meira Castro, Ana C.; Caetano, Nídia Sá; Silva, A. Ferreira daSome of the main challenges in Incorporating Sustainable Development practices into Engineering Education reside in establishing the bridge between concept and application. In particular the relation between value creation and the knowledge economy, innovation and entrepreneurship, as the main vehicles to a relevant application of the sustainable development concept, is not yet part of the majority of the engineering curricula in schools. Porto Polytechnical Engineering School (ISEP), a Global Reporting Initiative training partner in Portugal, as just presented its Sustainable Development Action Plan, with the main objective of creating a new kind of engineers, with Sustainable Development at the core of their degrees. The plan has several issues like publish an annual sustainability report, sustainable buildings, minimization of energy consumption and water policy, waste management, sustainable mobility, green procurement, EMAS certification, research and postgraduate activity and promotion of lectures and seminars in Sustainable Development.
- Symbolic Manipulation for Optimization of Boolean Functions for Control of Pneumatic and Electropneumatic CircuitsPublication . Silva, A. Ferreira da; Santos, Adriano ANeste artigo é descrito um programa desenvolvido em PROLOG, que realiza uma manipulação simbólica computacional dos Mapas de Karnaugh (MK), para obter o conjunto de equações lógicas otimizadas que possibilite o controlo de circuitos pneumáticos ou electropneumáticos. A manipulação simbólica de um MK é governada por um conjunto de regras genéricas que permitem obter a minimização/otimização de equações lógicas para controlo do circuito. Essa complexidade advém da explosão combinatória que resulta do aumento do número de cilindros que constituem o ciclo a automatizar. As abordagens de aprendizagem simbólica foram implementadas realizando uma busca no espaço de padrões simbólicos do MK. Esta busca permite com o uso de regras, reduzir o universo de procura no espaço de padrões simbólicos e, obter a solução ideal para controlar o circuito pneumático ou electropneumático desejado