Razvoj in model anizotropnega magnetnega senzorja s spremenljivo upornostjo

DOMAJNKO, DORA (author), Križaj, Dejan (mentor)

Cilj magistrskega dela je bil izdelava predloga za izvedbo anizotropnega senzorja s spremenljivo upornostjo. Naloga nas postopno vodi skozi proces načrtovanja in optimizacije izdelka, njen glavni del pa je izdelava treh matematičnih modelov za simulacijo delovanja, izdelanih glede na področje uporabe. Prvi splošni model je namenjen grobi simulaciji senzorja v vrtljivem magnetnem polju, optimizaciji s stališča višine in postavitve ter vplivov zunanjih motenj. Drugi model izvaja algoritem za optimizacijo oblike nanosa AMR materiala za dosego kar najbolj pravilnega odziva senzorja v polju, ki ga povzroča izmenično namagneten magnetni trak. Tretji model poskuša posnemati histerezno obnašanje samega materiala in posledično izhod senzorja pri prehajanju skozi vrtljivo magnetno polje poljubne jakosti. Nekatere uporabljene metode so metoda končnih elementov, interpolacija, metoda Monte Carlo (prilagojena za optimizacijo glede na izbrano uteženo kriterijsko funkcijo), aproksimacija z metodo najmanjših kvadratov ter Preisachov diskretni model histereze. Za posplošitev modela histereze za obnašanje v polju s spremenljivo smerjo sem razvila posplošen Preisachov model po komponentah, ki pa se je izkazal za neustreznega. Namesto tega sem razvila nov, na opazovanjih temelječ model s približkom premice oz. hiperbole. Na podlagi poznavanja delovanja AMR senzorjev, analize podobnih izdelkov na tržišču in izboljšav, preverjenih s pomočjo teh matematičnih modelov, predlagam končno podobo novega senzorja. V času pisanja tega besedila je ta še v procesu izdelave, zato še ni bilo mogoče ovrednotiti njegovega delovanja.

• Language: Slovenian
• Keywords: AMR senzor, računalniški model, optimizacijski algoritem, histereza
• Work type: Master's thesis/paper
• Organization: FE - Faculty of Electrical Engineering
• Year: 2016
• PID: 20.500.12556/RUL-84919
• Publication date in RUL: 08.09.2016

Secondary language

• Language: English
• Title: Development and modeling of an anisotropic magnetoresistive sensor with varying resistivity

Abstract

This thesis follows the process of design and optimization of anisotropic magneto resistive sensor. Its main focus is on the design of a computational model for simulation of a sensor. I have designed three different models, regarding the purpose. The first and most general model was designed to simulate the rough behaviour of a sensor in a rotating magnetic field, optimization of position and height and the influence of external magnetic disturbances. The second model carries out the algorithm for optimization of a shape of a deposit of AMR material to achieve the best response in a magnetic field of a magnetic scale. Third model simulates the hysteresial behaviour of a material and consequently the overall delay in sensor’s output while moving through the rotating magnetic field. Some of the used methods are the finite elements method, interpolation, Monte Carlo method (adapted for optimization according to the chosen weighted criterial function), approximation with the least-squares method and Preisach discrete hysteresis model. To generalize the model of hysteresis to simulate the behaviour in the magnetic field with a variable direction, a generalized Preisach model for each component was developed, but it turned out to be false. Therefore, I have proposed a new experience-based model. It approximates the hysteresis with the line or hyperbola. According to the knowledge about AMR effect, commercially available AMR products and improvements, tested by these models, I proposed a final design of a new sensor. Unfortunately at the time of writing this thesis, the product was not yet finished and therefore not evaluated.

• Keywords: AMR sensor, computational model, optimization algorithm, hysteresis