Architectures and design patterns for functional design of logic control and diagnostics in industrial automation

Recently in most of the industrial automation process an ever increasing degree of automation has been observed. This increasing is motivated by the higher requirement of systems with great performance in terms of quality of products/services generated, productivity, efficiency and low costs in the design, realization and maintenance. This trend in the growth of complex automation systems is rapidly spreading over automated manufacturing systems (AMS), where the integration of the mechanical and electronic technology, typical of the Mechatronics, is merging with other technologies such as Informatics and the communication networks. An AMS is a very complex system that can be thought constituted by a set of flexible working stations, one or more transportation systems. To understand how this machine are important in our society let considerate that every day most of us use bottles of water or soda, buy product in box like food or cigarets and so on. Another important consideration from its complexity derive from the fact that the the consortium of machine producers has estimated around 350 types of manufacturing machine. A large number of manufacturing machine industry are presented in Italy and notably packaging machine industry,in particular a great concentration of this kind of industry is located in Bologna area; for this reason the Bologna area is called “packaging valley”. Usually, the various parts of the AMS interact among them in a concurrent and asynchronous way, and coordinate the parts of the machine to obtain a desiderated overall behaviour is an hard task. Often, this is the case in large scale systems, organized in a modular and distributed manner. Even if the success of a modern AMS from a functional and behavioural point of view is still to attribute to the design choices operated in the definition of the mechanical structure and electrical electronic architecture, the system that governs the control of the plant is becoming crucial, because of the large number of duties associated to it. Apart from the activity inherent to the automation of themachine cycles, the supervisory system is called to perform other main functions such as: emulating the behaviour of traditional mechanical members thus allowing a drastic constructive simplification of the machine and a crucial functional flexibility; dynamically adapting the control strategies according to the different productive needs and to the different operational scenarios; obtaining a high quality of the final product through the verification of the correctness of the processing; addressing the operator devoted to themachine to promptly and carefully take the actions devoted to establish or restore the optimal operating conditions; managing in real time information on diagnostics, as a support of the maintenance operations of the machine. The kind of facilities that designers can directly find on themarket, in terms of software component libraries provides in fact an adequate support as regard the implementation of either top-level or bottom-level functionalities, typically pertaining to the domains of user-friendly HMIs, closed-loop regulation and motion control, fieldbus-based interconnection of remote smart devices. What is still lacking is a reference framework comprising a comprehensive set of highly reusable logic control components that, focussing on the cross-cutting functionalities characterizing the automation domain, may help the designers in the process of modelling and structuring their applications according to the specific needs. Historically, the design and verification process for complex automated industrial systems is performed in empirical way, without a clear distinction between functional and technological-implementation concepts and without a systematic method to organically deal with the complete system. Traditionally, in the field of analog and digital control design and verification through formal and simulation tools have been adopted since a long time ago, at least for multivariable and/or nonlinear controllers for complex time-driven dynamics as in the fields of vehicles, aircrafts, robots, electric drives and complex power electronics equipments. Moving to the field of logic control, typical for industrial manufacturing automation, the design and verification process is approached in a completely different way, usually very “unstructured”. No clear distinction between functions and implementations, between functional architectures and technological architectures and platforms is considered. Probably this difference is due to the different “dynamical framework”of logic control with respect to analog/digital control. As a matter of facts, in logic control discrete-events dynamics replace time-driven dynamics; hence most of the formal and mathematical tools of analog/digital control cannot be directly migrated to logic control to enlighten the distinction between functions and implementations. In addition, in the common view of application technicians, logic control design is strictly connected to the adopted implementation technology (relays in the past, software nowadays), leading again to a deep confusion among functional view and technological view. In Industrial automation software engineering, concepts as modularity, encapsulation, composability and reusability are strongly emphasized and profitably realized in the so-calledobject-oriented methodologies. Industrial automation is receiving lately this approach, as testified by some IEC standards IEC 611313, IEC 61499 which have been considered in commercial products only recently. On the other hand, in the scientific and technical literature many contributions have been already proposed to establish a suitable modelling framework for industrial automation. During last years it was possible to note a considerable growth in the exploitation of innovative concepts and technologies from ICT world in industrial automation systems. For what concerns the logic control design, Model Based Design (MBD) is being imported in industrial automation from software engineering field. Another key-point in industrial automated systems is the growth of requirements in terms of availability, reliability and safety for technological systems. In other words, the control system should not only deal with the nominal behaviour, but should also deal with other important duties, such as diagnosis and faults isolations, recovery and safety management. Indeed, together with high performance, in complex systems fault occurrences increase. This is a consequence of the fact that, as it typically occurs in reliable mechatronic systems, in complex systems such as AMS, together with reliable mechanical elements, an increasing number of electronic devices are also present, that are more vulnerable by their own nature. The diagnosis problem and the faults isolation in a generic dynamical system consists in the design of an elaboration unit that, appropriately processing the inputs and outputs of the dynamical system, is also capable of detecting incipient faults on the plant devices, reconfiguring the control system so as to guarantee satisfactory performance. The designer should be able to formally verify the product, certifying that, in its final implementation, it will perform itsrequired function guarantying the desired level of reliability and safety; the next step is that of preventing faults and eventually reconfiguring the control system so that faults are tolerated. On this topic an important improvement to formal verification of logic control, fault diagnosis and fault tolerant control results derive from Discrete Event Systems theory. The aimof this work is to define a design pattern and a control architecture to help the designer of control logic in industrial automated systems. The work starts with a brief discussion on main characteristics and description of industrial automated systems on Chapter 1. In Chapter 2 a survey on the state of the software engineering paradigm applied to industrial automation is discussed. Chapter 3 presentes a architecture for industrial automated systems based on the new concept of Generalized Actuator showing its benefits, while in Chapter 4 this architecture is refined using a novel entity, the Generalized Device in order to have a better reusability and modularity of the control logic. In Chapter 5 a new approach will be present based on Discrete Event Systems for the problemof software formal verification and an active fault tolerant control architecture using online diagnostic. Finally conclusive remarks and some ideas on new directions to explore are given. In Appendix A are briefly reported some concepts and results about Discrete Event Systems which should help the reader in understanding some crucial points in chapter 5; while in Appendix B an overview on the experimental testbed of the Laboratory of Automation of University of Bologna, is reported to validated the approach presented in chapter 3, chapter 4 and chapter 5. In Appendix C some components model used in chapter 5 for formal verification are reported.

Lo sviluppo dell'allevamento in Emilia-Romagna Aspetti economici e implicazioni sociali nella gestione della risorsa animale durante l’età del Bronzo

Il dibattito sullo sviluppo delle culture dell’età del Bronzo nel territorio dell’Emilia-Romagna sta portando una rinnovata attenzione sull’area romagnola. Le indagini si sono concentrate sull’area compresa tra il fiume Panaro e il Mare Adriatico, riconoscibile nell’odierna Romagna ed in parte della bassa pianura emiliana. Si trattava un territorio strategico, un vero e proprio crocevia socio-economico fra la cultura terramaricola e quelle centro italiche di Grotta Nuova. La presente ricerca di dottorato ha portato alla ricostruzione dei sistemi di gestione e di sfruttamento delle risorse animali in Emilia-Romagna durante l’Età del Bronzo, con particolare attenzione alla definizione della capacità portante ambientale dei diversi territori indagati e delle loro modalità di sfruttamento in relazione alla razionalizzazione della pratiche di allevamento. Sono state studiate in dettaglio le filiere di trasformazione dei prodotti animali primari e secondari definendo, quindi, i caratteri delle paleoeconomie locali nel processo di evoluzione della Romagna durante l’età del Bronzo. La ricerca si è basata sullo studio archeozoologico completo su 13 siti recentemente indagati, distribuiti nelle provincie di: Bologna, Ferrara, Ravenna, Forlì/Cesena e Rimini, e su una revisione completa delle evidenze archeozoologiche prodotte da studi pregressi. Le analisi non si sono limitate al riconoscimento delle specie, ma hanno teso all’individuazione ed alla valutazione di parametri complessi per ricostruire le strategie di abbattimento e le tecniche di sfruttamento e macellazione dei diversi gruppi animali. E’ stato possibile, quindi, valutare il peso ecologico di mandrie e greggi sul territorio e l’impatto economico ed ecologico di un allevamento sempre più sistematico e razionale, sia dal punto di vista dell’organizzazione territoriale degli insediamenti, sia per quanto riguarda le ripercussioni sulla gestione delle risorse agricole ed ambientali in generale.

Ricerche sull'allungamento di compenso in greco antico. Fonetica, fonologia, dialettologia.

La mia tesi offre uno studio sistematico di tutti i cambiamenti fonetici classificabili come 'Allungamento di Compenso' (AC) nella storia del greco antico. L'importanza di tali allungamenti vocalici nella fonologia storica e nella dialettologia del greco è, naturalmente, ben nota, ma diversi sviluppi individuali sono ancora discussi o poco chiari. Particolare attenzione è stata riservata all'odierno dibattito sull'AC nell'àmbito della fonologia teorica, e ad applicare correttamente i principi della linguistica generale ai fatti greci. Per ciascuna istanza di AC in greco, ho cercato di proporre una soluzione che sia coerente tanto con altri sviluppi noti del greco, sia con le tendenze attestate interlinguisticamente. Il greco risulta confermare la recente visione secondo cui non c'è un'unica regola o meccanismo responsabile dell'AC, ma esistono diverse tipologie, che in parte operano direttamente a livello della struttura fonologica astratta, in parte risultano dalla fonologizzazione di cambiamenti graduali e foneticamente condizionati. Entrambi i tipi risultano ben rappresentati in greco. Tuttavia, una tipologia di AC che è stata spesso postulata per il greco (l'AC da degeminazione) non è mai esistita in questa lingua. L'ultima parte di questo studio è dedicata a quattro casi separati di apparenti irregolarità nella distribuzione dell'AC o nel timbro della vocale lunga risultante. Dopo un'analisi filologica ed etimologica di tutto il materiale rilevante, si propongono delle spiegazioni per queste irregolarità.

Operating System Contribution to Composable Timing Behaviour in High-Integrity Real-Time Systems

The development of High-Integrity Real-Time Systems has a high footprint in terms of human, material and schedule costs. Factoring functional, reusable logic in the application favors incremental development and contains costs. Yet, achieving incrementality in the timing behavior is a much harder problem. Complex features at all levels of the execution stack, aimed to boost average-case performance, exhibit timing behavior highly dependent on execution history, which wrecks time composability and incrementaility with it. Our goal here is to restitute time composability to the execution stack, working bottom up across it. We first characterize time composability without making assumptions on the system architecture or the software deployment to it. Later, we focus on the role played by the real-time operating system in our pursuit. Initially we consider single-core processors and, becoming less permissive on the admissible hardware features, we devise solutions that restore a convincing degree of time composability. To show what can be done for real, we developed TiCOS, an ARINC-compliant kernel, and re-designed ORK+, a kernel for Ada Ravenscar runtimes. In that work, we added support for limited-preemption to ORK+, an absolute premiere in the landscape of real-word kernels. Our implementation allows resource sharing to co-exist with limited-preemptive scheduling, which extends state of the art. We then turn our attention to multicore architectures, first considering partitioned systems, for which we achieve results close to those obtained for single-core processors. Subsequently, we shy away from the over-provision of those systems and consider less restrictive uses of homogeneous multiprocessors, where the scheduling algorithm is key to high schedulable utilization. To that end we single out RUN, a promising baseline, and extend it to SPRINT, which supports sporadic task sets, hence matches real-world industrial needs better. To corroborate our results we present findings from real-world case studies from avionic industry.