Diskreettiaikainen liukuvan moodin säätö kiinteäoksidipolttokennon DC-tasonnostossa

Huoli ympäristön tilasta ja fossiilisten polttoaineiden hinnan nousu ovat vauhdittaneet tutkimusta uusien energialähteiden löytämiseksi. Polttokennot ovat yksi lupaavimmista tekniikoista etenkin hajautetun energiantuotannon, varavoimalaitosten sekä liikennevälineiden alueella. Polttokenno on tehonlähteenä kuitenkin hyvin epäideaalinen, ja se asettaa tehoelektroniikalle lukuisia erityisvaatimuksia. Polttokennon kytkeminen sähköverkkoon on tavallisesti toteutettu käyttämällä galvaanisesti erottavaa DC/DC hakkuria sekä vaihtosuuntaajaa sarjassa. Polttokennon kulumisen estämiseksi tehoelektroniikalta vaaditaan tarkkaa polttokennon lähtövirran hallintaa. Perinteisesti virran hallinta on toteutettu säätämällä hakkurin tulovirtaa PI (Proportional and Integral) tai PID (Proportional, Integral and Derivative) -säätimellä. Hakkurin epälineaarisuudesta johtuen tällainen ratkaisu ei välttämättä toimi kaukana linearisointipisteestä. Lisäksi perinteiset säätimet ovat herkkiä mallinnusvirheille. Tässä diplomityössä on esitetty polttokennon jännitettä nostavan hakkurin tilayhtälökeskiarvoistusmenetelmään perustuva malli, sekä malliin perustuva diskreettiaikainen integroiva liukuvan moodin säätö. Esitetty säätö on luonteeltaan epälineaarinen ja se soveltuu epälineaaristen ja heikosti tunnettujen järjestelmien säätämiseen.

A modified contour error controller for a high speed XY table

This article deals with a contour error controller (CEC) applied in a high speed biaxial table. It works simultaneously with the table axes controllers, helping them. In the early stages of the investigation, it was observed that its main problem is imprecision when tracking non-linear contours at high speeds. The objectives of this work are to show that this problem is caused by the lack of exactness of the contour error mathematical model and to propose modifications in it. An additional term is included, resulting in a more accurate value of the contour error, enabling the use of this type of motion controller at higher feedrate. The response results from simulated and experimental tests are compared with those of common PID and non-corrected CEC in order to analyse the effectiveness of this controller over the system. The main conclusions are that the proposed contour error mathematical model is simple, accurate, almost insensible to the feedrate and that a 20:1 reduction of the integral absolute contour error is possible.

Speed Control of an Autonomous Mobile Robot: Comparison between a PID Control and a Control Using Fuzzy Logic

An Autonomous Mobile Robot battery driven, with two traction wheels and a steering wheel is being developed. This Robot central control is regulated by an IPC, which controls every function of security, steering, positioning localization and driving. Each traction wheel is operated by a DC motor with independent control system. This system is made up of a chopper, an encoder and a microcomputer. The IPC transmits the velocity values and acceleration ramp references to the PIC microcontrollers. As each traction wheel control is independent, it's possible to obtain different speed values for each wheel. This process facilities the direction and drive changes. Two different strategies for speed velocity control were implemented; one works with PID, and the other with fuzzy logic. There were no changes in circuits and feedback control, except for the PIC microcontroller software. Comparing the two different speed control strategies the results were equivalent. However, in relation to the development and implementation of these strategies, the difficulties were bigger to implement the PID control.

Analysis of open CNC architecture for machine tools

The evolution of digital circuit technology, leadind to higher speeds and more reliability allowed the development of machine controllers adapted to new production systems (e.g., Flexible Manufacturing Systems - FMS). Most of the controllers are developed in agreement with the CNC technology of the correspondent machine tool manufacturer. Any alterations or adaptation of their components are not easy to be implemented. The machine designers face up hardware and software restrictions such as lack of interaction among system's elements and impossibility of adding new function. This is due to hardware incompatibility and to software not allowing alterations in the source program. The introduction of open architecture philosophy propitiated the evolution of a new generation of numeric controllers. This brought the conventional CNC technology to the standard IBM - PC microcomputer. As a consequence, the characteristics of the CNC (positioning) and the microcomputer (easy of programming, system configuration, network communication etc) are combined. Some researchers have addressed a flexible structure of software and hardware allowing changes in the hardware basic configuration and all control software levels. In this work, the development of open architecture controllers in the OSACA, OMAC, HOAM-CNC and OSEC architectures is described.

Professionalization of controllers in Finland

Professions are a special category of occupations that possesses exclusive rights over its domain of expertise. Professions apply expert knowledge in their work by using professional discretion and judgment to solve their clients’ problems. With control over their expert knowledge base, professions are able to control the supply of practitioners in their field and regulate the practice in their market. Professionalization is the process during which occupations attempt to gain the status of a profession. The benefits of becoming a profession are extensive – professional autonomy, social and financial rewards, prestige, status, and an exclusive community are only a few of the privileges that established professions possess. Many aspiring occupations have tried and failed to gain the status of a profession and one of these groups is the occupation of controllers in Finland. The objective of this study to uncover, why controllers have not professionalized, which properties of the occupation correspond with the elements generally regarded to pertain to professions, and which aspects of the occupational group may hinder the professionalization project. The professionalization project of controllers is analyzed using a multi-actor model of professionalization, in which practitioners, clients, the state, training institutions, and employing organizations are considered to affect the project. The properties of the occupation of controllers are compared to features generally associated with professions. The research methodology for this thesis is qualitative, and the study is conducted as an exploratory research. The data is primarily gathered using semi-structured interviews, which were conducted between March and May 2013 lasting from 40 minutes to an hour. In total, four controllers were interviewed, who worked for different companies operating in different industries, and whose experience of working as a controller varied between a few years to nearly 15 years. The data in this study indicates that although controllers possess qualities that distinguish professions from other occupational groups, the professionalization of controllers may not be plausible. Controllers enjoy considerable autonomy in organizations, and they possess a strong orientation towards serving their clients. The more profound problem with the occupation is its non-exclusive, indistinct knowledge base that does not rely solely on a single knowledge base. Controllers’ expertise is relatively organization-specific and built on several different fields of knowledge and not just management accounting, which could be considered as their primary knowledge base. In addition, controllers have not organized themselves, which is a quintessential, but by no means a sufficient prerequisite for professionalization.

Endogenous vasopressin and the central control of heart rate during dynamic exercise

The present article contains a brief review on the role of vasopressinergic projections to the nucleus tractus solitarii in the genesis of reflex bradycardia and in the modulation of heart rate control during exercise. The effects of vasopressin on exercise tachycardia are discussed on the basis of both the endogenous peptide content changes and the heart rate response changes observed during running in sedentary and trained rats. Dynamic exercise caused a specific vasopressin content increase in dorsal and ventral brainstem areas. In accordance, rats pretreated with the peptide or the V1 blocker into the nucleus tractus solitarii showed a significant potentiation or a marked blunting of the exercise tachycardia, respectively, without any change in the pressure response to exercise. It is proposed that the long-descending vasopressinergic pathway to the nucleus tractus solitarii serves as one link between the two main neural controllers of circulation, i.e., the central command and feedback control mechanisms driven by the peripheral receptors. Therefore, vasopressinergic input could contribute to the adjustment of heart rate response (and cardiac output) to the circulatory demand during exercise.

Ei kaikkea pidä sekoittaa ahdisteluun”. Tyttöjen internetissä saamat ja lähettämät seksiin liittyvät viestit

Tässä tutkimuksessa tarkastelen seksiin liittyviä viestejä, joita 11–18-vuotiaat tytöt ovat vastaanottaneet ja lähettäneet internetissä. Aineisto on kerätty kyselytutkimuksella, johon vastasi 1269 suomalaista, internetiä aktiivisesti käyttävää nuorta. Julkisessa keskustelussa lasten internetissä saamat seksiin liittyvät yhteydenotot tuomitaan haitallisiksi. Lähettäjien epäillään yleensä olevan aikuisia. Aineiston analyysi kuitenkin osoittaa, että haittojen lisäksi tyttöjen nettiseksikulttuuriin kuuluu paljon positiivisiksi koettuja asioita. Tytöt esimerkiksi pelaavat keskenään seksuaalissävytteisiä roolipelejä, harrastavat nettiseksiä omana itsenään, juttelevat toisten kanssa kokemuksista ja oppivat lisää seksiin liittyvistä asioista. 65 prosenttia tutkituista tytöistä on vastaanottanut seksiin liittyviä viestejä internetissä. Itse niitä on lähettänyt 20 prosenttia vastaajista. Tytöt ovat saaneet viestejä niin toisilta nuorilta kuin aikuisiltakin. Osa viesteistä koetaan epämiellyttävinä, osa mukavina ja osa vitseinä. Merkittävä osa vastaajista ei pohdi viestejä sen tarkemmin: Ne koetaan luonnolliseksi osaksi nettikulttuuria tai niiden ajatellaan olevan harmittomia. Aineiston analyysin lisäksi tutkimuksessa käsitellään lasten netinkäyttöön liitettyjä riskejä, jotka liittyvät jollakin tavalla seksiin. Näitä ovat esimerkiksi pedofilia ja lapsipornokuvat. Aiempaa tutkimusta keskustelutetaan aineiston kanssa. Erityisenä keskustelukumppanina käytetään EU Kids Online -projektin tutkimuksia niin Suomesta kuin muistakin Euroopan maista.

Indoor NO2 air pollution and lung function of professional cooks

Studies of cooking-generated NO2 effects are rare in occupational epidemiology. In the present study, we evaluated the lung function of professional cooks exposed to NO2 in hospital kitchens. We performed spirometry in 37 cooks working in four hospital kitchens and estimated the predicted FVC, FEV1 and FEF25-75, based on age, sex, race, weight, and height, according to Knudson standards. NO2 measurements were obtained for 4 consecutive days during 4 different periods at 20-day intervals in each kitchen. Measurements were performed inside and outside the kitchens, simultaneously using Palm diffusion tubes. A time/exposure indicator was defined as representative of the cumulative exposure of each cook. No statistically significant effect of NO2 exposure on FVC was found. Each year of work as a cook corresponded to a decrease in predicted FEV1 of 2.5% (P = 0.046) for the group as a whole. When smoking status and asthma were included in the analysis the effect of time/exposure decreased about 10% and lost statistical significance. On predicted FEF25-75, a decrease of 3.5% (P = 0.035) was observed for the same group and the inclusion of controllers for smoking status and asthma did not affect the effects of time/exposure on pulmonary function parameter. After a 10-year period of work as cooks the participants of the study may present decreases in both predicted FEV1 and FEF25-75 that can reach 20 and 30%, respectively. The present study showed small but statistically significant adverse effects of gas stove exposure on the lung function of professional cooks.

Avaliação de controles PID adaptativos para um sistema de aquecimento resistivo de água

O trabalho consiste na implementação de um controle convencional PID/SISO-feedback para obter um ajuste fino na temperatura de entrada da água de aquecimento em um processo de pasteurização. Para isto utilizou-se uma resistência de 2500 Watts instalada na linha do fluido secundário da seção de aquecimento do pasteurizador e um Pt100 para a medição de sua temperatura. Como o comportamento desta temperatura em função de uma mesma perturbação degrau de potência na resistência é dependente da vazão de trabalho, objetivou-se encontrar um controle único para que a mesma fosse mantida no set-point desejado na faixa de operação de vazão da água do processo (300 a 700L/h). Três sintonias para o controlador adaptativo PID foram testadas: a primeira consistiu na implementação de uma função adaptativa dos parâmetros PID, ajustada através dos valores individuais obtidos para cada vazão de trabalho conforme metodologia da curva de reação do processo; a segunda consistiu em configurar os parâmetros do PID com os valores médios destes calculados individualmente para cada vazão, e a terceira consistiu na sintonia através de uma função adaptativa ajustada pelos parâmetros de sintonia obtidos pela metodologia de Aström & Hägglund. A avaliação do desempenho das sintonias dos controladores adaptativos foi realizada por comparação dos valores dos índices de erro, obtidos por perturbações do sistema em malha fechada na vazão de água. Os resultados obtidos mostraram que dentre as sintonias testadas, a terceira sintonia, popularmente conhecida como "Bang-Bang", apresentou menores oscilações e os menores valores dos índices de erros.

Autosintonización de lazos de control PID en controladores programables por David Cavada Hernández

Tesis (Maestría en Ciencias de la Ingeniería Eléctrica con Especialidad en Electrónica) U.A.N.L.

Automatic Analysis and Synthesis of Controllers for Dynamical Systems Based On P

I present a novel design methodology for the synthesis of automatic controllers, together with a computational environment---the Control Engineer's Workbench---integrating a suite of programs that automatically analyze and design controllers for high-performance, global control of nonlinear systems. This work demonstrates that difficult control synthesis tasks can be automated, using programs that actively exploit and efficiently represent knowledge of nonlinear dynamics and phase space and effectively use the representation to guide and perform the control design. The Control Engineer's Workbench combines powerful numerical and symbolic computations with artificial intelligence reasoning techniques. As a demonstration, the Workbench automatically designed a high-quality maglev controller that outperforms a previous linear design by a factor of 20.

Plan Integral de Desarrollo PID 2004-2019. Actualización 2009. Desarrollo con calidad e identidad

Con el propósito de consolidar una cultura de planeación, gestión organizacional y evaluación permanente que le permita a la Universidad continuar en su proceso de modernización y direccionar sus esfuerzos hacia el cumplimiento de la misión institucional, y dando continuidad a los procesos de planeación emprendidos en la década de los 90, desde el año 2002 se inició el proceso de definición de un plan integral de desarrollo que respondiera a las necesidades del momento y que al mismo tiempo proyectara la Universidad en el futuro. Desde esta perspectiva, el Plan Integral de Desarrollo 2004-2015 (PID 2004-2015) permitió actualizar la visión de la Universidad proyectada al año 2015 e identificar los ejes estratégicos y de apoyo, así como los programas y subprogramas de acción orientados al cumplimiento de dicha visión. Esta dinámica, además de fomentar la participación de todos los actores de la comunidad rosarista, posibilitó la alineación estratégica frente al Plan.

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