COMPENSATION OF HYSTERESIS OF AN ANISOTROPIC MAGNETORESISTIVE SENSOR FOR POSITIONING OR ROTATIONAL APPLICATIONS USING THE LAGGING-DOMAIN MODEL

Pri avtomatizaciji pozicionirnih sistemov ključno vlogo igrajo dajalniki položaja, to so naprave, ki merijo linearni pomik oziroma kotni zasuk premičnih delov. Zahteve za točnost, robustnost in ponovljivost se z napredkom tehnologije stalno zaostrujejo. Pogosta rešitev je uporaba dajalnikov z vgrajenimi tipali na anizotropni magnetouporovni princip, ki se odlično obnesejo v zahtevnem industrijskem okolju. Pri slednjih eno pomembnejših omejitev predstavlja magnetna histereza. Namen pričujočega dela je analiza pojava histereze in njenih posledic na meritev, izdelava matematičnega modela za simulacijo histerezne napake na nivoju dajalnika, nazadnje pa še integracija modela v obliki algoritma, ki omogoča kompenzacijo merilne napake v realnem času. Sledi izpeljava kalibracije modelskih parametrov in eksperimentalna verifikacija predlaganega kompenzacijskega postopka.Doktorska disertacija obravnava pojav histereze na izbranem tipu tipala na anizotropni magnetouporovni princip (AMR) za merjenje linearnega pomika vzdolž izmenično namagnetenega traku. Pojasnjeno je delovanje tovrstnega tipala ter uporaba proizvedenih signalov na višjem nivoju, nivoju dajalnika. AMR pojav je razložen s pomočjo spinsko-orbitalne sklopitve valenčnih elektronov v niklju in železu, ki sestavljata senzorski material permaloj. Slednji najpogosteje nastopa v obliki tankega filma, nanešenega na silicijevo rezino s fotolitografskimi postopki, kar nam omogoča, da njegove magnetne lastnosti aproksimiramo z dogajanjem v eni sami magnetni domeni. V doktorskem delu smo uporabili Stoner-Wohlfarthov model, ki opisuje odvisnost usmerjenosti magnetizacije magnetne domene od zunanje magnetne poljske jakosti in anizotropije – izraženosti lahke osi magnetizacije, ter z njim opisali posamezne odseke tipala. Model smo nato razširili na celotno tipalo ter izvedli simulacijo celostnega odziva sestava območij, ki so glede na prostorsko razporeditev izpostavljena različnemu zunanjemu polju. S tem smo pokazali, da lahko histerezni odziv AMR tipala razložimo s pomočjo energijskega ravnovesja posameznih magnetnih domen. V nadaljevanju je predstavljeno širše področje matematičnega modeliranja histereze. Ugotovitve nam skupaj z razumevanjem fizikalnega dogajanja v materialu pomagajo pri konstrukciji lastnega modela na podlagi operatorja »domena« iz družine operatorjev play Vpliv histereze računamo s pomočjo utežene vsote stanj posameznih domen in z ustreznimi prilagoditvami za dane vhodne parametre in periodičnost računane veličine – kota znotraj magnetnega pola. Model je preizkušen s kvalitativno primerjavo z meritvami pri izbranih parametrih. Predlagan je postopek za meritev, s pomočjo katere pridobimo histerezne parametre danega tipala ob danih okoliščinah meritve (tipalni razdalji, temperaturi, jakosti magnetnega aktuatorja…). Izpeljana je matematična pretvorba teh parametrov v vhodne parametre modela. S tem je mogoče model zaostajajočih domen (MZD) na stabilen in robusten način umeriti za izbrani sistem. Za namen kvantitativne analize uspešnosti modela in kasneje kompenzacijskega algoritma je razvita kriterijska funkcija za izračun ustreznega kazalnika NMH (napaka meritve dajalnika zaradi histereze). Model MZD smo implementirali v programsko opremo dajalnika in ga uporabili za kompenzacijo histereze. Algoritem smo preizkusili na skupini testnih vzorcev raznovrstnih magnetouporovnih tipal. Ugotovljeno je bilo do 90% zmanjšanje napake zaradi histereze ob ustrezni uporabi kompenzacijskega postopka. Pri tem se delovni cikel dajalnika ni bistveno podaljšal. S tem smo potrdili uporabnost predlaganega algoritma za kompenzacijo histereze s pomočjo modela zaostajajočih domen, ki smo ga širši javnosti predstavili v [1].The key element of an automatized positioning system is an encodera device which measures the linear movement or angular rotation of the moving parts. The demands for accuracy, repeatability and robustness increase rapidly as the technology is progressing. Encoders with embedded anisotropic magnetoresistive sensors are a well-established solution for harsh industrial environments. However, magnetic hysteresis remains one of their main drawbacks. The purpose of this work is to analyze the hysteresis phenomena and its effects on the measurement, the construction of a mathematical model for simulations of the error due to hysteresis on the encoder level, and the integration of presented model in an algorithm for real-time compensation of the measurement error. Then we propose a calibration routine for model parameters and experimentally verify the overall algorithm. The hysteresis phenomenon is observed on a chosen type of an anisotropic magnetoresistive sensor (AMR) for linear measurement of a displacement along an interchangeably magnetized scale. The measuring principle is explained, firstly on a sensor level and secondly how the produced signals are used on the higher level, level of the encoder. AMR effect is explained through the spin-orbit interaction of the valence electrons in nickel and iron, main two ingredients in sensing material permalloy. The latter is usually deposited on a silicon wafer thorough photolithographic technique. Its thin-film structure allows us to approximate its magnetic properties with a single magnetic domain. The Stoner-Wohlfarth model was used to describe the orientation of magnetization of the material in dependence of external magnetic field strength and the anisotropy along the easy axis of the domain. After modeling a small piece of permalloy, the model was extended to a whole sensor area where parts of the material are exposed to different external fields according to their spatial position. Thus, we have shown that hysteresis behavior of AMR can be explained through the energy equilibrium of each magnetic domain. Furthermore, we present the field of mathematical hysteresis modeling. Along with the physical understanding of the phenomena we were able to construct a new model, based on »domain« operator from the family of mathematical operators play. Hysteresis effect is calculated as a weighted sum of states of domains. Some adaptations must be introduced due to the periodic nature of the input and output quantity as we are measuring the position within a magnetic period. The results of the simulation were qualitatively compared to the measurements. The model was thus verified for the chosen set of parameters. We have proposed a routine, through which one is able to measure the parameters of the hysteresis of a sensor under given circumstances (ride height, temperature, the strength of the actuator…). The measured parameters are then transformed into input parameters for the model. Thus, one can adjust the lagging domain model (MZD) to their system in a stable and robust way. In order to quantitatively describe the effectiveness of the model and later the compensating algorithm, a criterion function was proposed which calculates the value of an indicator NMH (ang. HME, the error of encoder due to hysteresis). The MZD model was finally implemented into firmware of an encoder and used for hysteresis error compensation. The algorithm was tested on a group of magnetoresistive sensor samples of various types. The error due to hysteresis has decreased for up to 90% when the compensation was properly applied. The duty-cycle of the encoder was not significantly prolonged. Thus, we have proven the usability of the proposed algorithm for compensation of the hysteresis error, based on the lagging-domain model. The algorithm was presented to the scientific community in [1]

Designing of symbolic and photorealistic 3D cartographic presentation

In the last few decades cartography experienced essential changes, due to the development of science and new technology. Computer tec hnology enabled new possibilities for the use of maps and designing of new formats for the cartographic presentations, which enable the user to more efficient acquisition of space data. One of these state -of-the-art cartographical presentations is the 3D map, which improves the understanding and comprehension of the height presentation. This thesis deals with the process of designing and forming of 3D maps and hereby focuses on the characteristics and differences between the symbolic and the photorealistic 3D cartographic presentation. It discusses graphical variables used for designing the cartographical content on the 3D map, and the generalization in the 3D cartographical model, which is the essential key for a quality 3D map. The design and formation of the 3D map is tested on a practical case: the 3D cartographical presentation of the town of Ljutomer, namely as the symbolic and as the photorealistic 3D presentation. The area of the presentation is carefully selected and includes the urban environment as well as the majority of natural elements. Individual views in the symbolic and photorealistic 3D cartographical model represent the same geographical area which enables an efficient comparison of both 3D cartographical presentations

Creating maps for Slovenian adventure races

Slovenska avantura je šport, ki se dogaja v naravi in ima velik poudarek na orientaciji. Nepogrešljivi pripomočki za izvajanje disciplin in gibanje po terenu so različne vrste kart. Cilj diplomske naloge je opisati postopek priprave karte za Slovensko avanturo ter analizirati in opisati spremembe pri pripravi in izdelavi kart v zadnjem desetletju. V analizo smo vključili predvsem vrste uporabljenih virov, njihove glavne značilnosti in izboljšave, spremembe pri postopkih izdelave kart ter izboljšave na izdelanih kartah do sedaj. Opisana so redakcijska dela pri izdelavi kart, tehnologija izdelave ter predstavljeni tiskani primerki kart Slovenske avanture 2016.Adventure race Slovenia is a sport competition that takes place in nature and has a strong emphasis on orienteering skills. Different types of maps are indispensable tools for the implementation of disciplines and movements on the ground. The aim of the thesis is to describe the process of preparing maps for Adventure race Slovenia, to analyse and describe the changes in the preparation and creation of maps in the last decade. The analysis includes the types of sources used, their main features and improvements, changes in procedures of map making and improvements on maps created so far. It presents the drafting of map making, manufacturing technology and printed copies of maps of Adventure races Slovenia 2016

Dejavniki stresa med študenti

Neljubi sopotnik današnjega načina življenja je nedvomno stres, ki je neizogiben pojav uveljavitveno usmerjene družbe, kamor lahko uvrstimo tudi populacijo študentov. Študenti morajo izpolnjevati zahteve iz okolja, hkrati pa se soočajo z lastnimi sposobnostmi in interesi. Znaki stresa se lahko izražajo na različne načine in lahko vodijo do resnih zdravstvenih zapletov. Z namenom, da bi ugotovili dejavnike stresa med študenti, smo na Visoki šoli za zdravstvo v Ljubljani izvedli študijo, s katero smo dobili preliminarni vpogled v obravnavano problematiko. V kvantitativnem delu raziskave je sodeloval 101 študent. Po razdelitvi izjav v štiri kategorije, predstavijo dejavnike stresa naslednje vrednosti: 24,2 % intrapersonalne, 18,7 % interpersonalne, 40,9 % šola/služba, 16,2 % širše okolje. Najpogosteje zabeleženi dejavniki stresa ne glede na kategorijo so: šola (21,8 %), izpiti (7,4 %), preobremenjenost v šoli ali na delovnem mestu (7,0 %), družinske težave (6,7 %), hiter tempo življenja (5,3 %), finance (5,1 %), prepiri z bližnjimi (4,6 %), zgodnje vstajanje in težave s partnerjem (3,9 %). Tekstovno gradivo za kvalitativno analizo smo pridobili iz petih delno strukturiranih intervjujev. Prepoznane so bile tri kategorije: stresorji, znaki in način reagiranja. Znotraj kategorij so bile prepoznane še posamezne dimenzije. Kot ključno ugotovitev bi lahko navedli, da stresa v kateri koli njegovi teoretični komponenti ni mogoče raziskovati ločeno od konteksta pojavitve in doživljanja. Rezultati so večplastni in poglabljajo problematiko stresa med študenti z doživljajskega zornega kota. Prispevek želi opozoriti na prisotnost različnih dejavnikov stresa med populacijo študentov in vodi k razmišljanju o rešitvah za zmanjšanje in obvladovanje težav, s katerimi se srečuje obravnavana populacija

Preservation and access to records with geodata (Full Scale Pilot 5)

This report contains information gathered during the execution of E-ARK Pilot 5: Preservation and access to records with geodata

Records export, transfer and ingest recommendations and SIP Creation Tools

This report describes a software deliverable as it delivers a number of E-ARK tools: • ERMS Export Module (a tool for exporting records and their metadata from ERMS in a controlled manner); • Database Preservation Toolkit (a tool for exporting relational databases as SIARD 2.0 or other formats); • ESSArch Tools for Producer (a tool for SIP creation); • ESSArch Tools for Archive (a tool for SIP ingestion); • RODA-in (a tool for SIP creation); • Universal Archiving Module (a tool for SIP creation). In addition, an overview of Pre-Ingest and Ingest processes will be provided by this report which will help to understand the tools and their use

Documentation, Common Information and Short Overview of the E-ARK pilots

This report contains the common information and short overview of the pilots, along with references to the final version of the Pilot Definition Excel files and Pilot Documentation Packages

How do midwives in Slovenia view their professional status?

Objective: the aim of the study was to explore Slovenian midwives' views of their professional status. The influence of participants' educational background on their views was also examined, since higher education is related to professionalism. Design: this was a quantitative descriptive survey, using postal data collection. The questionnaire comprised of six elements crucial for professionalism - three elements distinctive of 'old' professionalism (power, ethics, specific knowledge) and three characteristics of 'new' professionalism (reflective practice, inter-professional collaboration and partnership with users). Participants: a total of 300 midwives who were registered in a national register of nurses and midwives at the time of the study. The response rate was 50.7% (152 returned the questionnaire). Participants that were on a probationary period were excluded, leaving 128 questionnaires for analysis (43%). Some 40.9% participants had secondary midwifery education, 56.7% had higher midwifery education and only few (2.4%) finished postgraduate education. Findings: the majority of participants did not consider midwifery to be a specific profession. Midwives with secondary education were more likely to consider practical skills to be important than theoretical midwifery knowledge. In general midwives did not feel enabled to practice autonomously; and this caused them to face ethical dilemmas when aiming to fulfil women's wishes. All participants with midwifery secondary school education thought that obstetrics jeopardises midwifery scope of practice, but only half of the BSc participants thought this. One-fifth of all participants estimated that midwifery is also threatened by nursing. The respondents reported feeling a lack of control over their professional activity and policy making; however the majority of midwives claimed that they were willing to take on more responsibility for independent practice. Key conclusions: Slovenian midwifery cannot be considered to be a profession yet. It faces several hindrances, due to its historical development. Implications for practice: in order to develop a specific professional identity for midwives, the content and structure of education should be analysed and changed in order to improve socialisation and professionalism. In clinical settings, the scope of midwifery practice and responsibilities, as defined by EU directives, should be agreed by all professional groups