Browsing by Author "Casavola, Alessandro"

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    Distributed command governor strategies for multi-agent dynamical systems
    (2011-11-23) Francesco Tedesco, Francesco Tedesco; Palopoli, Luigi; Casavola, Alessandro
    This dissertation presents a class of novel distributed supervision strategies for multi-agent linear systems connected via data networks and subject to coordination constraints. Such a coordination-by-constraint paradigm is characterized by a set of spatially distributed dynamic systems, connected via communication channels, with possibly dynamical coupling amongst them which need to be supervised and coordinated in order to accomplish their overall objective. The basic design philosophy of the Command Governor (CG) set-point management is used here in order to maintain a pre-stabilized system within prescribed constraints. While in traditional CG schemes the set-point manipulation is undertaken on the basis of the actual measure of the state, in this dissertation it is shown that the CG design problem can be solved also in the case that such an explicit measure is not available by forcing the state evolutions to stay ”not too far” from the manifold of feasible steady-states. This approach, referred to as Feed-Forward CG (FF-CG), is a convenient solution to be used in distributed applications where the cost of measuring the overall state and distributing it amongst the agents may be a severe limitation. Several distributed strategies, based both on CG and FF-CG ideas, will be fully described and analyzed. First, we propose some “non-iterative” schemes in which the agents acting as supervisors communicate once during the decision process. In this respect, a “sequential” distributed strategy in which only one agent at the time is allowed to manipulate its own reference signal is proposed. Such a strategy, although interesting by itself in some applications, will be instrumental to introduce a more effective “parallel” distributed strategy, in which all agents are allowed, under certain conditions, to modify their own reference signals simultaneously. Then an “iterative” procedure, borrowed from the literature, has been here adapted in order to build more efficient distributed schemes which however require larger amount of data exchanges for their implementation. With the aim of evaluating the distributed methods here proposed, several cases of study involving the coordination autonomous vehicles, power networks and water networks management are illustrated.
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    Innovative Techniques to Support the Surveying and the Exploration of Underwater Sites by Scientific and Recreational Divers
    (Università della Calabria, 2021-05-14) Mangeruga, Marino; Crupi, Felice; Casavola, Alessandro; Bruno, Fabio; Pupo, Francesco
    In the submerged environment divers often suffer from low visibility conditions that make difficult the orientation within an underwater site. At present, there is a lack of technologies and tools supporting the divers to better orientate themselves in the underwater environment and to simplify their comprehension of the context. The research aims to design and develop innovative solutions to support divers, both recreative and technical/scientific ones, through a novel system for underwater navigation and exploration, providing them with underwater geo-localization, contextualized information, augmented reality (AR) contents and recommendation about the optimal path to follow during the dive. A first aspect on which the research work focused is the Underwater Image Enhancement. This study has led to the development of a software tool to enhance underwater images with well-known methods at the SoA. A benchmark of these well-known methods has been produced and some guidelines to evaluate the underwater image enhancement methods have been formulated. The effort of this part of the research has been to guide the community towards the definition of a more effective and objective methodology for the evaluation of underwater image enhancement methods. Another aspect of the research concerned the Underwater Navigation and Underwater AR (UWAR). A software for underwater tablets, namely Divy, has been designed and developed to support divers’ navigation and exploration. It enables the divers to access different features such as the visualization of a map of the underwater site that allows them to know their position within the submerged site, the possibility to acquire geo-localized data, the visualization of additional information about specific points of interest and the communication with the surface operators through an underwater messaging system. On this basis, the UWAR concept applied in Underwater Cultural Heritage sites has been designed and developed as well, consisting of an augmented visualization representing a hypothetical 3D reconstruction of the archaeological remains as they appeared in the past. The geo-localization is provided by an acoustic localization system, but this kind of technology suffers from a low update rate, and cannot be employed alone for the AR purpose. To improve the performance of the UWAR and provide the users with a smooth AR visualization, a hybrid technique that merges data from an acoustic localization system with data coming from a visual inertial-odometry framework has been conceived and developed to deliver positioning information with a higher update rate with respect to the acoustic system alone. In particular, given the low update rate of the acoustic system, a strategy has been implemented aimed to fill the gaps between two consecutive acoustic positioning data. User testing has been conducted to assess the effectiveness and potential of the developed UWAR technologies. Finally, an innovative approach to dive planning based on an original underwater pathfinding algorithm has been conceived. It computes the best 3D path to follow during the dive in order to maximise the number of Points of Interest (POIs) visited, while taking into account the safety limitations strictly related to scuba diving. This approach considers the morphology of the 3D space in which the dive takes place to compute the best path, taking into account the diving decompression limits and avoiding the obstacles through the analysis of a 3D map of the site.
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    Metodi di fusione dei dati per sistemi di assistenza alla guida
    (2012-10-24) Lupia, Marco; Palopoli, Luigi; Casavola, Alessandro
    Questo documento riporta tutta l'attivit a svolta durante il corso di dottora- to riguardo lo studio, l'applicazione e la sperimentazione di metodi di Data Fusion nell'ambito dei sistemi avanzati di assistenza alla guida per il miglio- ramento delle prestazioni e dell'a dabilit a. In linea di principio, sembra ra- gionevole a ermare che combinando in modo ottimale le informazioni proveni- enti da pi u sensori e possibile progettare e realizzare un sistema meno sensibile alle variazioni ambientali e a possibili errori di misura dovuti alla presenza di outliers. Tuttavia, dal punto di vista pratico i costi aggiuntivi che si devono sostenere, sia in termini di hardware necessario alla raccolta dei dati dai sen- sori addizionali che per la necessit a di disporre di sistemi di calcolo pi u potenti, potrebbero non essere giusti cati se i miglioramenti ottenuti nelle situazioni pi u probabili e pi u realistiche di utilizzo sono modesti. Il presente documento o re, innanzitutto, una panoramica su vari algoritmi di visione arti ciale utilizzati per il riconoscimento della segnaletica orizzon- tale e per la stima del tempo di invasione (tTLC). Quest'ultimo parametro gioca un ruolo determinante nell'avvertimento tempestivo del conducente in caso di superamento dei limiti della carreggiata. I vari algoritmi sono stati testati in varie condizioni di guida, valutandone le prestazioni conseguibili e il carico computazionale richiesto. Segue un'analisi dello stato dell'arte dei metodi e delle tecniche di Data Fu- sion pi u promettenti e che che meglio si prestano a migliorare l'accuratezza del calcolo della stima del tempo di invasione ttlc grazie alla disponibilit a di altri sensori oltre alla telecamera. Speci catamente, si sono confrontati i vari meto- di e algoritmi di Data Fusion, particolarizzati rispetto a vari modelli matem- atici della vettura e ai sensori disponibili, valutando le loro prestazioni in situ- azioni tipiche di guida e soprattutto rispetto all'errore percentuale di stima del tempo di invasione ttlc ottenuto, valutando anche il carico computazionale corrispondente. Gli algoritmi pi u promettenti sono stati implementati su piattaforma embedded.Questo documento riporta tutta l'attivit a svolta durante il corso di dottora- to riguardo lo studio, l'applicazione e la sperimentazione di metodi di Data Fusion nell'ambito dei sistemi avanzati di assistenza alla guida per il miglio- ramento delle prestazioni e dell'a dabilit a. In linea di principio, sembra ra- gionevole a ermare che combinando in modo ottimale le informazioni proveni- enti da pi u sensori e possibile progettare e realizzare un sistema meno sensibile alle variazioni ambientali e a possibili errori di misura dovuti alla presenza di outliers. Tuttavia, dal punto di vista pratico i costi aggiuntivi che si devono sostenere, sia in termini di hardware necessario alla raccolta dei dati dai sen- sori addizionali che per la necessit a di disporre di sistemi di calcolo pi u potenti, potrebbero non essere giusti cati se i miglioramenti ottenuti nelle situazioni pi u probabili e pi u realistiche di utilizzo sono modesti. Il presente documento o re, innanzitutto, una panoramica su vari algoritmi di visione arti ciale utilizzati per il riconoscimento della segnaletica orizzon- tale e per la stima del tempo di invasione (tTLC). Quest'ultimo parametro gioca un ruolo determinante nell'avvertimento tempestivo del conducente in caso di superamento dei limiti della carreggiata. I vari algoritmi sono stati testati in varie condizioni di guida, valutandone le prestazioni conseguibili e il carico computazionale richiesto. Segue un'analisi dello stato dell'arte dei metodi e delle tecniche di Data Fu- sion pi u promettenti e che che meglio si prestano a migliorare l'accuratezza del calcolo della stima del tempo di invasione ttlc grazie alla disponibilit a di altri sensori oltre alla telecamera. Speci catamente, si sono confrontati i vari meto- di e algoritmi di Data Fusion, particolarizzati rispetto a vari modelli matem- atici della vettura e ai sensori disponibili, valutando le loro prestazioni in situ- azioni tipiche di guida e soprattutto rispetto all'errore percentuale di stima del tempo di invasione ttlc ottenuto, valutando anche il carico computazionale corrispondente. Gli algoritmi pi u promettenti sono stati implementati su piattaforma embedded.
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    Metodi e algoritmi per il riconoscimento del livello di distrazione e affaticamento nella guida di autoveicoli
    (2012-10-24) Cario, Gianni; Palopoli, Luigi; Casavola, Alessandro
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    New Engine control functions for CO2 reduction and performance improvement
    (2011-11-23) Montalto, Iolanda; Palopoli, Luigi; Casavola, Alessandro
    Today’s automotive market is extremely competitive and quickly changing. The customers demand excellent driving performance, new legislations impose increasingly stricter constraints and competition imposes increasingly shorter development cycles because of reduced times-to-market. Environmental awareness and public concerns about CO2 emissions have been for a long time a substantial factor in promoting technological advancements in the automotive industry. In this scenario, the actual high penetration of electronic devices in cars is and will be a key factor for the fulfillment of all the above requirements. In fact, in a recent study it has been estimated that 90% of automotive innovation includes the electrical and electronics parts. On the other side, next generation of engines will increase in complexity, functionalities and self monitoring capabilities, with true shifts in technology, like e.g. intelligent alternators and variable valve actuation systems. In this respect, the contents of this thesis summarize my last four years of research activity which has been carried out in the field of engine control systems design and validation. Actually, the problem of the production of polluting substances during the combustion phases depends not only by the engine structure but also on the engine management system. Therefore, the control software plays an important role in the achievement of suitable engine and vehicle performance while maintaining low emission levels. To this end, the complexity of the software functions needs to be increased, both in terms of algorithmic complexity and for the need to handle the additional degrees of freedom available (i.e. model based torque management during take off, valve timing or valve actuation management, different values for battery voltage and so on). In turn, the larger control systems complexity imposes the use of more sophisticated tools and methods for the optimization of the engine control system parameters. Most of the work underlying this thesis has been carried out in the automotive company where I actually work for and reports the results of the many efforts accomplished in addressing such kind of problems. In particular, the research activities have been undertaken and experimented on a gasoline engine equipped with a Variable Valve Actuation (VVA) module. The potentialities of VVA systems represent the actual frontier of the engine technology and therefore such a kind of engine represents a relevant baseline for experimenting novel approaches. In particular, four main topics have been investigated: the first one regards the design of smart alternator management algorithms that allow the achievement of lower emission levels than standard alternators and improve the performance during certain manoeuvres. The second topic regards the development of a new method, named drive off algorithm, for handling the take off phases. This algorithm has been proved so effective in test benches that it has been implemented in all commercial vehicles since the beginning of this year. The third and fourth topics have regarded the way to manage the additional algorithmic complexity due to the availability of the further degrees offered by the new VVA technology. For this reason, a new spark advance algorithm has been developed, being the standard one not so good in adequately taking into account the specificities of the VVA technology. A second more complex aspect being addressed it has been the increased number of engine control parameters to be calibrated for this new kind of engines. The old tuning methodology based on a trial-and-error approach resulted not enough accurate for the novel control requirements and too much time-consuming. A novel tuning methodology has been developed which, on the contrary, is based on an optimization approach and allows one to achieve the desired accuracy in short times. For this reason, it has been adopted in my company since last year and it is actually used for steady state calibration of each motorization of MULTIAIR® engines. The thesis is organized in eight chapters The first and second ones describe the scenario in which my work has been developed, showing the restrictive emission levels required in the automobile world and some technological enhancements for fuel economy, emission legislation fulfillment and engine performance improvements. In the third chapter, the control algorithms developed to manage the smart alternator technology are described, showing the achieved benefits. The details of the control algorithms and the obtained results have been described in the paper (SAE2011) [12]. The fourth chapter describes the control functions used to improve the engine performance during the take off maneuver in MULTIAIR® engines. This work has been published in the paper (EAEC2011) [11]. In the fifth chapter a control function that optimizes the performance of a VVA engine has been detailed. This algorithm calculates the spark ignition timing (one of the necessary engine parameters) in order to obtain the optimal behavior in each engine working mode and in each variable valve mode. This work has been presented at the Fisita 2010 Conference (see [10]). The tools and the methodology developed for the optimization of the engine parameters have been described in another paper presented at the same conference (see [9]). In the sixth chapter, several tools for engine control systems design and calibration have been described. This chapter contains material published in the book’s chapter [16]) and in the conference papers [71], [78], [79], [80], [81]. The seventh chapter concludes the thesis, reporting some results and showing the benefits of the proposed methodologies on a real application