Broadband excitation in the system identification of active magnetic bearing rotor systems

One of the targets of the climate and energy package of the European Union is to increase the energy efficiency in order to achieve a 20 percent reduction in primary energy use compared with the projected level by 2020. The energy efficiency can be improved for example by increasing the rotational speed of large electrical drives, because this enables the elimination of gearboxes leading to a compact design with lower losses. The rotational speeds of traditional bearings, such as roller bearings, are limited by mechanical friction. Active magnetic bearings (AMBs), on the other hand, allow very high rotational speeds. Consequently, their use in large medium- and high-speed machines has rapidly increased. An active magnetic bearing rotor system is an inherently unstable, nonlinear multiple-input, multiple-output system. Model-based controller design of AMBs requires an accurate system model. Finite element modeling (FEM) together with the experimental modal analysis provides a very accurate model for the rotor, and a linearized model of the magneticactuators has proven to work well in normal conditions. However, the overall system may suffer from unmodeled dynamics, such as dynamics of foundation or shrink fits. This dynamics can be modeled by system identification. System identification can also be used for on-line diagnostics. In this study, broadband excitation signals are adopted to the identification of an active magnetic bearing rotor system. The broadband excitation enables faster frequency response function measurements when compared with the widely used stepped sine and swept sine excitations. Different broadband excitations are reviewed, and the random phase multisine excitation is chosen for further study. The measurement times using the multisine excitation and the stepped sine excitation are compared. An excitation signal design with an analysis of the harmonics produced by the nonlinear system is presented. The suitability of different frequency response function estimators for an AMB rotor system are also compared. Additionally, analytical modeling of an AMB rotor system, obtaining a parametric model from the nonparametric frequency response functions, and model updating are discussed in brief, as they are key elements in the modeling for a control design. Theoretical methods are tested with a laboratory test rig. The results conclude that an appropriately designed random phase multisine excitation is suitable for the identification of AMB rotor systems.

Generalizing sample tree information with semiparametric and parametric models

Summary

Description of three new arctic bramble cultivars and proposal for cultivar identification

Selostus: Kolmen uuden mesimarjalajikkeen kuvaukset ja lajikekuvausohjeet mesimarjalle ja jalomaaraimelle

Identification of Research Portfolio for the Development of Filtration Equipment

This piece of work which is Identification of Research Portfolio for Development of Filtration Equipment aims at presenting a novel approach to identify promising research topics in the field of design and development of filtration equipment and processes. The projected approach consists of identifying technological problems often encountered in filtration processes. The sources of information for the problem retrieval were patent documents and scientific papers that discussed filtration equipments and processes. The problem identification method adopted in this work focussed on the semantic nature of a sentence in order to generate series of subject-action-object structures. This was achieved with software called Knowledgist. List of problems often encountered in filtration processes that have been mentioned in patent documents and scientific papers were generated. These problems were carefully studied and categorized. Suggestions were made on the various classes of these problems that need further investigation in order to propose a research portfolio. The uses and importance of other methods of information retrieval were also highlighted in this work.

On Modelling, System Identification and Control of Servo-Systems with a Flexible Load

The present study was done with two different servo-systems. In the first system, a servo-hydraulic system was identified and then controlled by a fuzzy gainscheduling controller. The second servo-system, an electro-magnetic linear motor in suppressing the mechanical vibration and position tracking of a reference model are studied by using a neural network and an adaptive backstepping controller respectively. Followings are some descriptions of research methods. Electro Hydraulic Servo Systems (EHSS) are commonly used in industry. These kinds of systems are nonlinearin nature and their dynamic equations have several unknown parameters.System identification is a prerequisite to analysis of a dynamic system. One of the most promising novel evolutionary algorithms is the Differential Evolution (DE) for solving global optimization problems. In the study, the DE algorithm is proposed for handling nonlinear constraint functionswith boundary limits of variables to find the best parameters of a servo-hydraulic system with flexible load. The DE guarantees fast speed convergence and accurate solutions regardless the initial conditions of parameters. The control of hydraulic servo-systems has been the focus ofintense research over the past decades. These kinds of systems are nonlinear in nature and generally difficult to control. Since changing system parameters using the same gains will cause overshoot or even loss of system stability. The highly non-linear behaviour of these devices makes them ideal subjects for applying different types of sophisticated controllers. The study is concerned with a second order model reference to positioning control of a flexible load servo-hydraulic system using fuzzy gainscheduling. In the present research, to compensate the lack of dampingin a hydraulic system, an acceleration feedback was used. To compare the results, a pcontroller with feed-forward acceleration and different gains in extension and retraction is used. The design procedure for the controller and experimental results are discussed. The results suggest that using the fuzzy gain-scheduling controller decrease the error of position reference tracking. The second part of research was done on a PermanentMagnet Linear Synchronous Motor (PMLSM). In this study, a recurrent neural network compensator for suppressing mechanical vibration in PMLSM with a flexible load is studied. The linear motor is controlled by a conventional PI velocity controller, and the vibration of the flexible mechanism is suppressed by using a hybrid recurrent neural network. The differential evolution strategy and Kalman filter method are used to avoid the local minimum problem, and estimate the states of system respectively. The proposed control method is firstly designed by using non-linear simulation model built in Matlab Simulink and then implemented in practical test rig. The proposed method works satisfactorily and suppresses the vibration successfully. In the last part of research, a nonlinear load control method is developed and implemented for a PMLSM with a flexible load. The purpose of the controller is to track a flexible load to the desired position reference as fast as possible and without awkward oscillation. The control method is based on an adaptive backstepping algorithm whose stability is ensured by the Lyapunov stability theorem. The states of the system needed in the controller are estimated by using the Kalman filter. The proposed controller is implemented and tested in a linear motor test drive and responses are presented.

Strategy Implementation Bottlenecks: Identification, Analysis and Removal

This thesis investigates the strategy implementation process of enterprices; a process whichhas lacked the academic attentioon compared with a rich strategy formation research trdition. Strategy implementation is viewed as a process ensuring tha the strtegies of an organisation are realised fully and quickly, yet with constant consideration of changing circumstances. The aim of this sudy is to provide a framework for identifying, analysing and removing the strategy implementation bottleneck af an organization and thus for intesifying its strategy process.The study is opened by specifying the concept, tasks and key actors of strategy implementation process; especially arguments for the critical implementation role of the top management are provided. In order to facilitate the analysis nad synthetisation of the core findings of scattered doctrine, six characteristic approaches to strategy implementation phenomenon are identified and compared. The Bottleneck Framework is introduced as an instrument for arranging potential strategy realisation problems, prioritising an organisation's implementation obstacles and focusing the improvement measures accordingly. The SUCCESS Framework is introduced as a mnemonic of the seven critical factors to be taken into account when promoting sttrategy implementation. Both frameworks are empirically tested by applying them to real strategy implementation intesification process in an international, industrial, group-structured case enterprise.

Key Account Management in Paper and Board Industry- Identification of Key Accounts for Stora Enso Graphical Boards

Tutkimuksen tarkoituksena oli tunnistaa nykyiset sek�� potentiaaliset avainasiakkaat case yritykselle. Avainasiakkaat tunnistettiin Chevertonin tunnistamis- ja valintamatriisin avulla, jossa asiakkaan sijoittumista matriisiin arvioidaan asiakkaan houkuttelevuuden sek�� toimittajan suhteellisten vahvuuksien avulla. Kriteereiksi avainasiakkaiden tunnistamiseen valittiin asiakkaan vuotuinen ostovolyymi, asiakkaan business-potentiaali sek�� case-yrityksen toimittajaosuus. Asiakkaat luokiteltiin avainasiakkaisiin, kehitett��viin avainasiakkaisiin, yll��pidett��viin asiakkaisiin sek�� satunnaisiin asiakkaisiin. Tutkimus tarjosi l��ht��kohdan case-yrityksen uusille avainasiakasp����llik��ille sek�� osoitti suunnan tulevaisuuden tutkimustarpeille. Aktiivisen tiedonvaihdannan kautta eri myyntikonttoreiden johtohenkil��st��n sek�� my��s yrityksen eri funktionaalisten divisioonien v��lill�� voidaan saavuttaa kilpailuetua kun l��hestyt����n asiakasta toimintojaan j��rkiper��isesti koordinoineena toimittajana samalla kun asiakkaat keskitt��v��t ostojaan. Jotta yrityksen tavoitteet, markkinamahdollisuudet sek�� resurssit olisivat hyvin tasapainossa, tulisi my��s asiakaskannattavuutta sek�� asiakkaiden strategista merkitt��vyytt�� arvioida ja mitata s����nn��llisesti t��ss�� tutkimuksessa k��ytettyjen tunnistuskriteereiden lis��ksi.

Identification and Management of Operational Risks in IT Organization of Financial Service Provider

Ty��n tavoitteena on tunnistaa toiminnallisia riskitekij��it�� rahoituspalveluita tarjoavan yrityksen IT-organisaatiossa sek�� l��yt���� arkip��iv��isi�� keinoja hallita n��it�� riskej��. Ty��ss�� riskej�� on my��s tarkasteltu mahdollisen ulkoistuksen yhteydess��. Fuusiot ovat yleisi�� rahoitusalan yrityksiss��. Yhteenliittymien tuloksena yritysten IT-arkkitehtuuri voi olla monimutkainen ja kulttuurierot yrityksess�� suuria. Synergia- ja mittakaavaetuja saadakseen yritys keskitt���� toimintojaan ja IT-ratkaisujaan. Riskien tunnistaminen on riskienhallintaprosessin t��rkein vaihe. T��ss�� tutkimuksessa riskit ja riskitekij��t tunnistettiin itsearvioinnin avulla kysymyssarjoja hyv��ksik��ytt��en. Monet riskitekij��t liittyiv��t sis��isen valvonnan ja seurannan puutteisiin. My��hemmin n��ille riskeille pohdittiin ty��ryhm��ss�� k��yt��nn��nl��heisi�� hallintakeinoja. Yritys voi siirt���� tai jakaa IT -riskej�� ulkoistamalla. Ulkoistaminen voi kuitenkin tuoda mukaan my��s uusia riskitekij��it��. Ennen ulkoistamisp����t��st�� yrityksen sis��isten prosessien ja organisaation on oltava j��rjestyksess��, jotta sopimuksen kannattavuutta voidaan verrata luotettavasti saman palvelun tuottamiseen sis��isesti.

Market Opportunities for Paper Industry in Radio Frequency Identification

The paper industry has been experiencing remarkable structural changes since paper demand growth has ceased and some markets are declining. One reason behind the declined demand is the Internet, which has partially substituted the newspaper as a source of information. Paper products alone can no longer provide livelihood, and the paper industry has to find new business areas. In this research, we studied radio frequency identification (RFID), and the market opportunities it could provide for paper industry. The research combined a quantitative industry analysis and qualitative interviews. RFID is a growing industry in the beginning of its life cycle, in which value chains and technologies still evolve significantly. The industry is going to concentrate on the future, and in the long term RFID-identifiers will probably be printed on paper substrate or directly onto products. Paper industry has the chance to enter the RFID industry, but it has to obtain the required competences, for example through acquisitions. The business potential RFID offers to paper industry is inadequate, and while reviewing new strategic options, the paper industry must consider more options, for example the entire printed intelligence.

Improving the Potentials of Logistics Processes: Identification and Solutions

The importance of logistics for companies is a well known and justified issue. Today, enterprises are developing their logistics processes in order to match their products and services to the requirements of the most important customers. Therefore there is a need for developing analysing tools for logistics and especially for analysing the significance of various customer service elements. The aim of this paper is to propose analytic tools for supporting strategic level logistics decision making by emphasizing service level elements on two levels: (1) to introduce and propose approaches to categorize the developing efforts of logistics and (2) to introduce and/or propose approaches for solving some customer service related strategic level logistics problems. This study consists of two parts. In the first part an overview of the work is presented, and the second part comprises eight research papers on the topic of the study. The overview includes an introduction, where strategic and tactical level logistics problems are discussed and the relation of logistics to marketing and customer service issues is presented. In the first part of the study the objectives, the structure, the research strategy and the contribution of the research are described, and the challenges for future research are discussed. In the second part the three first papers deal with the identification of objectives for logistics while the remaining five papaers concentrate on solving customer service related strategic level logistics problems.

Identification of Turning Points in the Research on Titanium Dioxide Production and Application

This dissertation "Identification of turning points in the research on titanium dioxide production and application" aims at detecting in scientific literatures emerging trends and sudden changes in titanium dioxide production and application. These key changes are then studied to determine its transient patterns and its effect on the research on titanium dioxide production and application The source of information is from bibliographic data which discussed titanium dioxide production and application. These bibliographic data where obtained from ISI Web of Knowledge and then formed into a network of clusters by applying software called Citespace.

Identification of the Emerging Issues in Recycled Fiber Processing

The objectives of this research work ���Identification of the Emerging Issues in Recycled Fiber processing��� are discovering of emerging research issues and presenting of new approaches to identify promising research themes in recovered paper application and production. The projected approach consists of identifying technological problems often encountered in wastepaper preparation processes and also improving the quality of recovered paper and increasing its proportion in the composition of paper and board. The source of information for the problem retrieval is scientific publications in which waste paper application and production were discussed. The study has exploited several research methods to understand the changes related to utilization of recovered paper. The all assembled data was carefully studied and categorized by applying software called RefViz and CiteSpace. Suggestions were made on the various classes of these problems that need further investigation in order to propose an emerging research trends in recovered paper.

Boundary identification in the domain of a parabolic partial differential equation

Bakgrunden och inspirationen till f��religgande studie ��r tidigare forskning i till��mpningar p�� randidentifiering i metallindustrin. Effektiv randidentifiering m��jligg��r mindre s��kerhetsmarginaler och l��ngre serviceintervall f��r apparaturen i industriella h��gtemperaturprocesser, utan ��kad risk f��r materielhaverier. I idealfallet vore en metod f��r randidentifiering baserad p�� uppf��ljning av n��gon indirekt variabel som kan m��tas rutinm��ssigt eller till en ringa kostnad. En dylik variabel f��r sm��ltugnar ��r temperaturen i olika positioner i v��ggen. Denna kan utnyttjas som insignal till en randidentifieringsmetod f��r att ��vervaka ugnens v��ggtjocklek. Vi ger en bakgrund och motivering till valet av den geometriskt endimensionella dynamiska modellen f��r randidentifiering, som diskuteras i arbetets senare del, framom en flerdimensionell geometrisk beskrivning. I de aktuella industriella till��mpningarna ��r dynamiken samt f��rdelarna med en enkel modellstruktur viktigare ��n exakt geometrisk beskrivning. L��sningsmetoder f��r den s.k. sidledes v��rmeledningsekvationen har m��nga saker gemensamt med randidentifiering. D��rf��r studerar vi egenskaper hos l��sningarna till denna ekvation, inverkan av m��tfel och n��got som brukar kallas f��rorening av m��tbrus, regularisering och allm��nnare f��ljder av icke-v��lst��lldheten hos sidledes v��rmeledningsekvationen. Vi studerar en upps��ttning av tre olika metoder f��r randidentifiering, av vilka de tv�� f��rsta ��r utvecklade fr��n en strikt matematisk och den tredje fr��n en mera till��mpad utg��ngspunkt. Metoderna har olika egenskaper med specifika f��rdelar och nackdelar. De rent matematiskt baserade metoderna karakteriseras av god noggrannhet och l��g numerisk kostnad, dock till priset av l��g flexibilitet i formuleringen av den modellbeskrivande partiella differentialekvationen. Den tredje, mera till��mpade, metoden k��nnetecknas av en s��mre noggrannhet f��rorsakad av en h��gre grad av icke-v��lst��lldhet hos den mera flexibla modellen. F��r denna gjordes ��ven en ansats till feluppskattning, som senare kunde observeras ��verensst��mma med praktiska ber��kningar med metoden. Studien kan anses vara en god startpunkt och matematisk bas f��r utveckling av industriella till��mpningar av randidentifiering, speciellt mot hantering av olinj��ra och diskontinuerliga materialegenskaper och pl��tsliga f��r��ndringar orsakade av ���nedfallande��� v��ggmaterial. Med de behandlade metoderna f��refaller det m��jligt att uppn�� en robust, snabb och tillr��ckligt noggrann metod av begr��nsad komplexitet f��r randidentifiering.