A new frequency dependent approach to model validation for iterative identification and control schemes

Classical validation methods “accept” or “reject” a model as a valid representation of a plant for some intended use. However this binary result has several problems as firstly, models are neither good nor bad but have a certain valid frequency range and secondly the procedure gives no insight into why the model is not useful or how to improve the model. Moreover within the framework of iterative identification and control design the model validation issue arises the following requirements: i) Is it possible to improve an existing model?. ii) How can the model be improved?. iii) How authoritative can be the designed controller?. These facts question the suitability of traditional model validation schemes in general and their suitability for iterative control schemes in particular. We present a new validation procedure that overtakes these problems by performing the model validation frequency dependent. The validation procedure is then more informative due to its frequency information content. As a result the same model can be validated for some frequency band and invalidated for a distinct frequency rang

Noves estratègies per al control automàtic de processos industrials

El grup d'Automatització i Sistemes Avançats de Control (ASAC) ha desenvolupat una configuració automàtica, per gestionar, de manera simultània i automàtica, els problemes de seguiment i regulació que poden ocórrer en alguns processos industrials.El grupo de Control y Sistemas Avanzados de Control (ASAC) ha desarrollado una configuración automática, para gestionar de forma simultánea y automática los problemas de seguimiento y regulación que pueden ocurrir en algunos procesos industriales.Nowadays, the practical whole of industrial processes takes place in a fully automated way. As a matter of fact it would be quite complicated from finding some case in that the task is, still, carried out in a manual way. This high level of automation has associated the realization of a set of tasks of very different nature in a totally automatic way

Intelligent Control of a Distributed Energy Generation System Based on Renewable Sources

The control of low power systems, which include renewable energy sources, a local network, an electrochemical storage subsystem and a grid connection, is inherently hierarchical. The lower level consists of the wind energy sources (power limitation at rated value in full load regime and energy optimization in partial load regime) and photovoltaic (energy conversion optimization) control systems. The present paper deals with control problem at the higher level and aims at generating the control solution for the energetic transfer between the system components, given that the powers of the renewable energy sources and the power in the local network have random characteristics. For the higher level, the paper proposes a mixed performance criterion, which includes an energy sub-criterion concerning the costs of electricity supplied to local consumers, and a sub-criterion related to the lifetime of the battery. Three variants were defined for the control algorithm implemented by using fuzzy logic techniques, in order to control the energy transfer in the system. Particular attention was given to developing the models used for the simulation of the distributed energy system components and to the whole control system, given that the objective is not the real-time optimization of the criterion, but to establish by numerical simulation in the design stage the "proper" parameters of the control system. This is done by taking into account the multi-criteria performance objective when the power of renewable energy sources and the load have random characteristics

Joint Environmental and Economical Analysis of Wastewater Treatment Plants Control Strategies : a Benchmark Scenario Analysis

In this paper, a joint environmental and economic analysis of different Wastewater Treatment Plant (WWTP) control strategies is carried out. The assessment is based on the application of the Life Cycle Assessment (LCA) as a method to evaluate the environmental impact and the Benchmark Simulation Model No. 1 (BSM1). The BSM1 is taken as the benchmark scenario used to implement the control strategies. The Effluent Quality Index (EQI) and the Overall Cost Index (OCI) are two indicators provided by BSM1 and used to evaluate the plant's performance from the efluent quality and the economic points of view, respectively. This work conducts a combined analysis and assessment of ten different control strategies defined to operate a wastewater treatment plant. This analysis includes the usual economic and performance indexes provided by BSM1 joined with the LCA analysis that determines the environmental impact linked to each one of the considered control strategies. It is shown how to get an overall evaluation of the environmental effects by using a normalized graphical representation that can be easily used to compare control strategies from the environmental impact point of view. The use of only the BSM1 indexes provides an assessment that leads to a clustering of control strategies according to the cost/quality tradeoff they show. Therefore, regarding the cost/quality tradeoff, all strategies in the same group are almost equal and do not provide an indication on how to proceed in order to select the appropriate one. It is therefore shown how the fact of adding a new, complementary, evaluation (LCA based) allows either to reinforce a decision that could be taken solely on the basis of the EQI/OCI tradeoff or to select one control strategy among the others

PI and Fuzzy Control for P-removal in Wastewater Treatment Plant

Due to the complex and non linear character, wastewater treatment process is difficult to be controlled. The demand for removing the pollutant, especially for nitrogen (N) and phosphorus (P), as well as reducing the cost of wastewater treatment plant is an important research theme recently. Thus, in this paper, the benchmark proposed default control strategy and 10 additional control strategies are applied on the combined biological P and N removal Benchmark Simulation Model No.1 (BSM1-P). In addition, according to the results of applying PI controllers, as usual, we also chose the group with the better performance, as well as the default control strategy, to replace the PI controllers with fuzzy controllers. In this way, it can be seen that in all cases the quality of effluent of the controlled process could be improved in some degree; and the fuzzy controllers get a better phosphorus removal

Millora del desenvolupament de competencies transversals mitjançant la col·laboració interuniversitaria

Aquesta comunicació presenta una experiència col·laborativa entre l'Escola Tècnica superior d'Enginyeria (ETSE), el servei d'activitat Física (SAF) de la UAB conjuntament amb l'Escola Politècnica de Catalunya a Vilanova i la Geltrú (EPSVG). La idea que es presenta i que motiva l'experiència es el fet d'explorar una nova manera de desenvolupar el projecte fi de carrera per als estudiants d'Enginyeria. Aquests projectes han d'obeir a les mateixes característiques que un projecte industrial real en el sentit de desenvolupar un "producte" que ha de funcionar. El SAF proporciona el marc ideal per a desenvolupar treballs d'aquest tipus dintre de l'àrea temàtica de l'automatització de sistemes. En la realització del projecte o problema a resoldre s'identifiquen diferents rols o paper en similitud als que l'estudiant s'acabarà trobant a la vida real. D'aquesta manera es promou la interacció entre els diferents grups i es motiva a que l'estudiant assumeixi les tasques associades al seu paper dintre del projecte global. D'aquesta manera, hi ha, per una banda, el client final del producte (que en el nostre cas es el SAF mateix) per al qual uns desenvolupadors han de dur a terme la tasca encomanda per tal de solucionar el problema presentat (aquest problema es presentat i detallat directament per el client en base a reunions). A més, s'identifica una tasca d'assessoria que, de manera intencionada, associem a estudiants de l'altra universitat i que hauran d'avaluar les tasques desenvolupades, emetre un judici i suggerir possibles vies de millora. Això obliga a presentar tan al client com al desenvolupador les seves conclusions, argumentar les decisions, etc Creiem que l'experiència es prou interessant com per veure si es extensible a altres dominis que nos siguin els purament tecnològics.This communication presents a collaborative experience among the superior technical college of Engineering (ETSE), the service of Physical Activity (SAF) of the UAB together with the Polytechnic School of Catalonia located in Vilanova i la Geltrú (EPSVG). The idea that is being introduced and that motivates the experience is the fact of exploring a new way to develop the final year project for the students of Engineering. These projects have to be due to the same characteristics than a real industrial project in the sense of developing a "product" that has to work. The SAF provides the ideal frame to develop works of this type in the thematic area of systems automation. In the realization of the project or problem to be solved they identify different roles in similarity to those that the student will end up finding itself in the real life real. In this way the interaction is promoted among the different groups and is motivated to the student assuming the tasks associated with its role in the global project. In this way, there is the final customer of the product, on the one hand (that in our case is played by the SAF) for which some developers have to carry out the associated task in order to solve the presented problem (this problem is presented and detailled directly by the customer with regard to meetings). Moreover, a consultancy task is identified such that, in an intentional way, we associate with students of another university and that will have to evaluate the developed tasks, that will have to issue a judgement and that will have to suggest possible ways of improvement. This forces to presenting to the customer as well as to the developer its conclusions, to argue the decisions, etc We believe that the experience is interesting enough to see if it could be extended to other domains than the purely technological ones

Model role-playing aplicat a projectes d’enginyeria

La finalitat bàsica del projecte es possibilitar la col•laboració entre dues Universitats (UPC, UAB) dins l'ámbit de la millora de la qualitat de la docència per tal de contribuir a introduir model de role-playing en l'àrea de l'enginyeria. Es a dir, mitjançant una estructura que emula l'àmbit professional, els estudiants dels darrers anys d'enginyeria poden fer practiques professionalitzadores, de forma d'escurçar la transició entre estudiantat universitari i enginyer professional. Els objectius del projecte s'enmarquen en la millora de la qualitat docent de les matèries impartides per tal de: reduir la distància entre la Universitat i Indústria incorporant projectes reals; afavorir la realimentació positiva de l'aprenentatge mitjançant l'avaluació continuada i la generació de material multimedia de qualitat.Peer Reviewe

Towards integral human-machine system conception: from automation design to usability concerns

The purpose of this communication is to show an additional advantage of the well known guide for start and stop modes, GEMMA, that should motivate its use as well as to introduce the consideration of the human operator as an integral part of the automation procedure. The inclusion of the human operator as well as his interplay with the automation device needs some guidelines that can be drawn from joining the GEMMA structured approach and some concepts borrowed from cognitive ergonomic theory and human-computer interaction. Finally, this paper shows some examples of humanmachine interfaces (industrial panel, interface display screen).Postprint (published version