Engineering framework for service-oriented automation systems

Tese de doutoramento. Engenharia Informática. Universidade do Porto. Faculdade de Engenharia. 201

Virtual Machine and Code Generator for PLC-Systems

In the programming of PLC-Systems (PLC = Programmable Logic Controller) in building automation there were no vital changes over the past few years. Most users of PLC-Systems in building automation do the programming in FBD (functional block diagram). The users always start their projects with the programming of the PLC software. After that the HMI (Human Machine Interface) or the SCADA-System (Supervisory Control And Data Acquisition) are added as subsequent Tasks. Programming tools like CoDeSys build on this bottom up approach. Most of the time the user has to cope with different tools for the different tasks and the programming tools are built for a specific hardware. Almost every PLC manufacturer has its own implementation of the IEC 61131 standard with various interpretations. So a change of hardware means that the programming tool, the way how to program the PLC-System, the HMI tool and the SCADA tool changes. The interfaces between the tools are sometimes pretty clumsy and software, generated with these tools, is often not easily transferred to the PLC-System of another PLC-System manufacturer. This investigation proposes a top down approach to a project. For the first time the starting point of a project will be the plant diagram. The programming will be intuitively done in the plant diagram. Template objects (e.g. for pumps) created with the object orientated paradigm will be used to accomplish this task. The created PLC software will run in a virtual machine on the PLC-System and thus will be reusable on PLC-Systems of different manufacturers, which will eliminate the dependency on certain hardware. The merging together of SCADA, HMI development and PLC programming will lead to a more natural way in programming PLC-Systems. In a first step the user draws his plant diagram with template objects (TO) and afterwards binds the template objects on the plant diagram together. With this approach the user only has to cope with a single software tool. The independency from the PLC hardware will be an additional alleviation for the user. The aim of the investigation is to determine the realisability of a generic SCADA-System FBD programming language, a virtual machine and a code generator for PLC-Systems

The DS-Pnet modeling formalism for cyber-physical system development

This work presents the DS-Pnet modeling formalism (Dataflow, Signals and Petri nets), designed for the development of cyber-physical systems, combining the characteristics of Petri nets and dataflows to support the modeling of mixed systems containing both reactive parts and data processing operations. Inheriting the features of the parent IOPT Petri net class, including an external interface composed of input and output signals and events, the addition of dataflow operations brings enhanced modeling capabilities to specify mathematical data transformations and graphically express the dependencies between signals. Data-centric systems, that do not require reactive controllers, are designed using pure dataflow models. Component based model composition enables reusing existing components, create libraries of previously tested components and hierarchically decompose complex systems into smaller sub-systems. A precise execution semantics was defined, considering the relationship between dataflow and Petri net nodes, providing an abstraction to define the interface between reactive controllers and input and output signals, including analog sensors and actuators. The new formalism is supported by the IOPT-Flow Web based tool framework, offering tools to design and edit models, simulate model execution on the Web browser, plus model-checking and software/hardware automatic code generation tools to implement controllers running on embedded devices (C,VHDL and JavaScript). A new communication protocol was created to permit the automatic implementation of distributed cyber-physical systems composed of networks of remote components communicating over the Internet. The editor tool connects directly to remote embedded devices running DS-Pnet models and may import remote components into new models, contributing to simplify the creation of distributed cyber-physical applications, where the communication between distributed components is specified just by drawing arcs. Several application examples were designed to validate the proposed formalism and the associated framework, ranging from hardware solutions, industrial applications to distributed software applications

Worker-robot cooperation and integration into the manufacturing workcell via the holonic control architecture

Cooperative manufacturing is a new field of research, which addresses new challenges beyond the physical safety of the worker. Those new challenges appear due to the need to connect the worker and the cobot from the informatics point of view in one cooperative workcell. This requires developing an appropriate manufacturing control system, which fits the nature of both the worker and the cobot. Furthermore, the manufacturing control system must be able to understand the production variations, to guide the cooperation between worker and the cobot and adapt with the production variations.Die kooperative Fertigung ist ein neues Forschungsgebiet, das sich neuen Herausforderungen stellt. Diese neuen Herausforderungen ergeben sich aus der Notwendigkeit, den Arbeiter und den Cobot aus der Sicht der Informatik in einem kooperativen Arbeitsplatz zu verbinden. Dies erfordert die Entwicklung eines geeigneten Produktionskontrollsystems, das sowohl der Natur des Arbeiters als auch der des Cobots entspricht. Darüber hinaus muss die Fertigungssteuerung in der Lage sein, die Produktionsschwankungen zu verstehen, um die Zusammenarbeit zwischen Arbeiter und Cobot zu steuern

A Model-based Approach for Designing Cyber-Physical Production Systems

The most recent development trend related to manufacturing is called "Industry 4.0". It proposes to transition from "blind" mechatronics systems to Cyber-Physical Production Systems (CPPSs). Such systems are capable of communicating with each other, acquiring and transmitting real-time production data. Their management and control require a structured software architecture, which is tipically referred to as the "Automation Pyramid". The design of both the software architecture and the components (i.e., the CPPSs) is a complex task, where the complexity is induced by the heterogeneity of the required functionalities. In such a context, the target of this thesis is to propose a model-based framework for the analysis and the design of production lines, compliant with the Industry 4.0 paradigm. In particular, this framework exploits the Systems Modeling Language (SysML) as a unified representation for the different viewpoints of a manufacturing system. At the components level, the structural and behavioral diagrams provided by SysML are used to produce a set of logical propositions about the system and components under design. Such an approach is specifically tailored towards constructing Assume-Guarantee contracts. By exploiting reactive synthesis techniques, contracts are used to prototype portions of components' behaviors and to verify whether implementations are consistent with the requirements. At the software level, the framework proposes a particular architecture based on the concept of "service". Such an architecture facilitates the reconfiguration of components and integrates an advanced scheduling technique, taking advantage of the production recipe SysML model. The proposed framework has been built coupled with the construction of the ICE Laboratory, a research facility consisting of a full-fledged production line. Such an approach has been adopted to construct models of the laboratory, to virtual prototype parts of the system and to manage the physical system through the proposed software architecture

Neuro-fuzzy software for intelligent control and education

Tese de mestrado integrado. Engenharia Electrotécnica e de Computadores (Major Automação). Faculdade de Engenharia. Universidade do Porto. 200

An industrial analytics methodology and fog computing cyber-physical system for Industry 4.0 embedded machine learning applications

Industrial cyber-physical systems are the primary enabling technology for Industry 4.0, which combine legacy industrial and control engineering, with emerging technology paradigms (e.g. big data, internet-of-things, artificial intelligence, and machine learning), to derive self-aware and self-configuring factories capable of delivering major production innovations. However, the technologies and architectures needed to connect and extend physical factory operations to the cyber world have not been fully resolved. Although cloud computing and service-oriented architectures demonstrate strong adoption, such implementations are commonly produced using information technology perspectives, which can overlook engineering, control and Industry 4.0 design concerns relating to real-time performance, reliability or resilience. Hence, this research compares the latency and reliability performance of cyber-physical interfaces implemented using traditional cloud computing (i.e. centralised), and emerging fog computing (i.e. decentralised) paradigms, to deliver real-time embedded machine learning engineering applications for Industry 4.0. The findings highlight that despite the cloud’s highly scalable processing capacity, the fog’s decentralised, localised and autonomous topology may provide greater consistency, reliability, privacy and security for Industry 4.0 engineering applications, with the difference in observed maximum latency ranging from 67.7% to 99.4%. In addition, communication failures rates highlighted differences in both consistency and reliability, with the fog interface successfully responding to 900,000 communication requests (i.e. 0% failure rate), and the cloud interface recording failure rates of 0.11%, 1.42%, and 6.6% under varying levels of stress

IT-palvelun tietotöiden automatisointi: Koneoppimismalli ohjelmistorobotille

Aging population, legacy systems and pressure on cost savings are all growing problems for modern-day companies. One relief for these problems is to automate business processes and IT-service desk tasks with software robots. The aim of the automation is to reduce employees' growing workload so that they have time to work with the more valuable tasks. One of the most limitating factors of using software robots are that the automated processes must be strictly rule-based and the input data must be highly structured. In business there has been a lot of talk about using machine learning and other AI-techniques for achieving more generic solutions, but the actual results have not yet been publicly recognised. In this thesis it is intended to examine the suitability of machine learning for software robotics by automating company's internal IT-services. The goal is to build a working solution and find a machine learning platform for the company that provides software robotic solutions as a service. The end result is a viable automation solution which uses machine learning model for probability-based decision making. Based on this research it is possible say that there exist synergy benefits between the two technologies, as long as there is a suitable application for them.Ikääntyvä väestö, vanhat järjestelmät ja paine kustannussäästöille ovat nykypäivän yritysten kasvavia ongelmia. Yksi helpotus näihin ongelmiin on liiketoimintaprosessien ja IT-palveluiden automatisointi ohjelmistorobottien avulla. Automatisoinnin pyrkimyksenä on vähentää työntekijöiden kasvavaa työtaakkaa, jotta heillä jää enemmän aikaa liiketoiminnalle tärkeämpien tehtävien hoitoon. Yksi suurimmista ohjelmistorobotiikan käyttöä rajoittavista tekijöistä on se, että automatisoitavien prosessien tulee olla tarkasti sääntöihin perustuvia, sekä hyödynnettävän tiedon tarkkaan jäsenneltyä. Alalla on ollut paljon puhetta koneoppimisen ja tekoälyn hyödyntämisestä geneerisempien ratkaisujen saavuttamiseen, mutta tuloksia näiden projektien onnistumisesta ei ole kantautunut suuren yleisön tietoisuuteen. Tässä työssä on tarkoitus tutkia koneoppimisen soveltuvuutta ohjelmistorobotiikkaan automatisoimalla yrityksen sisäisiä IT-palveluja. Päämääränä on rakentaa toimiva prototyyppi ja löytää koneoppimismalleja hyödyntävä alusta, jota prosessien automatisointia tarjoava yritys voisi alkaa käyttämään osana ratkaisukokonaisuuttaan. Lopputuloksena saatiin toimiva ratkaisu, joka höydyntää koneoppimista todennäköisyyksiin perustuvassa päätöksenteossa. Tutkimuksen avulla voidaan sanoa, että kahden tekniikan välillä on synergiahyötyjä, kunhan niille löydetään sopiva käyttökohde

Intuitive Instruction of Industrial Robots : A Knowledge-Based Approach

With more advanced manufacturing technologies, small and medium sized enterprises can compete with low-wage labor by providing customized and high quality products. For small production series, robotic systems can provide a cost-effective solution. However, for robots to be able to perform on par with human workers in manufacturing industries, they must become flexible and autonomous in their task execution and swift and easy to instruct. This will enable small businesses with short production series or highly customized products to use robot coworkers without consulting expert robot programmers. The objective of this thesis is to explore programming solutions that can reduce the programming effort of sensor-controlled robot tasks. The robot motions are expressed using constraints, and multiple of simple constrained motions can be combined into a robot skill. The skill can be stored in a knowledge base together with a semantic description, which enables reuse and reasoning. The main contributions of the thesis are 1) development of ontologies for knowledge about robot devices and skills, 2) a user interface that provides simple programming of dual-arm skills for non-experts and experts, 3) a programming interface for task descriptions in unstructured natural language in a user-specified vocabulary and 4) an implementation where low-level code is generated from the high-level descriptions. The resulting system greatly reduces the number of parameters exposed to the user, is simple to use for non-experts and reduces the programming time for experts by 80%. The representation is described on a semantic level, which means that the same skill can be used on different robot platforms. The research is presented in seven papers, the first describing the knowledge representation and the second the knowledge-based architecture that enables skill sharing between robots. The third paper presents the translation from high-level instructions to low-level code for force-controlled motions. The two following papers evaluate the simplified programming prototype for non-expert and expert users. The last two present how program statements are extracted from unstructured natural language descriptions