Razvoj inkrementalnega magnetnega rotacijskega dajalnika pozicije

ŽBOGAR, DOMINIK (author), Jankovec, Marko (mentor)

V tem diplomskem delu je predstavljen razvoj magnetnega inkrementalnega sistema za merjenje pozicije na gredi CNC stroja. Sistem je sestavljen iz dajalnika pozicije oziroma enkoderja in nosilca informacije, namagnetenega obroča. Magnetni obroč je radialno namagneten z določenim številom magnetnih period ter z eno referenčno značko na obrat. Nasajen je neposredno na gred, nad njim pa je nameščen dajalnik pozicije, ki s pomočjo senzorja AMR in Hallovih senzorjev bere magnetni zapis. Poleg senzorjev dajalnik pozicije vsebuje še interpolator in mikrokrmilnik, ki obdelata in pretvorita podatke v želeni tip informacije. Dajalnik pozicije je del zaprto-zančnega sistema oziroma hitrostne in pozicijske zanke, ki v realnem času spremlja premike gredi in jih pretvarja v podatke prilagojene krmilniku. Tako lahko krmilnik ustrezno krmili motor na gredi. Pojem magnetni dajalnik pozicije je precej obsežen, zato je diplomsko delo razdeljeno na več delov. Prvi del je namenjen informiranju bralca o principih in fizikalnih ozadjih magnetnih rotacijskih dajalnikov pozicije. Razjasnili si bomo osnovne pojme, ki spremljajo vsak dajalnik pozicije, kot so ločljivost, interpolacija in točnost. Spoznali bomo materiale, ki se uporabljajo pri trajnih magnetih, kako delujeta senzor AMR in Hallov senzor, ter na realnem primeru predstavili, kako deluje interpolator, in kakšno vlogo ima v dajalniku pozicije. V drugem delu je predstavljena zasnova dajalnika pozicije, ki je bil razvit na podlagi specifikacij kupca. Predstavljeno je, kako je bil zasnovan magnetni obroč, način magnetenja, in kako smo reševali težavo z visokimi vrtljaji. Predstavljena je blokovna shema elektronike ter delovanje programske kode. Tretji del predstavi uporabljeno programsko in strojno opremo, kako smo simulirali realen krmilnik za test dajalnika ter predstavitev testne naprave. V zadnjem delu diplomskega dela opišemo končno izvedbo dajalnika, nekaj glavnih testiranj, problemov, s katerimi smo se soočali, ter kako smo jih reševali.

• Language: Slovenian
• Keywords: rotacijski magnetni dajalnik pozicije, Hallov senzor, senzor AMR, interpolator, magnetni princip
• Work type: Undergraduate thesis
• Organization: FE - Faculty of Electrical Engineering
• Year: 2016
• PID: 20.500.12556/RUL-83105
• Publication date in RUL: 27.05.2016

Secondary language

• Language: English
• Title: Development of an incremental magnetic position encoder

Abstract

This thesis will present the development of magnetic incremental system for measuring the position on the shaft of CNC machine. The system consists of a position encoder and information carrier – magnetized ring. Magnetic ring is radially magnetized with a certain number of magnetic periods and contains one reference mark per revolution. It is mounted directly onto the shaft along with position encoder which reads the magnetic imprint utilizing Hall sensor and the AMR sensor. In addition to these sensors the position encoder contains an interpolator and a microcontroller which processe and convert data to a desired type of information. The position encoder is part of a closed-loop control system or the speed and position loop which monitors the movements of the shaft real-time and converts these movements into data adapted for the controller. This way the controller can appropriately control the motor on the shaft. The term magnetic position encoder is quite extensive so this thesis is divided into several parts. The first part is meant to inform the reader about the principles and physical background of magnetic rotary position sensors. We clarify the basic concepts that accompany each position encoder such as resolution, interpolation and accuracy. We learn about materials that are used for permanent magnets, how AMR sensor and Hall sensor work, as well as on a real case present how an interpolator works and what role it has inside the position encoder. The second part presents the design of the position encoder developed based on customer specifications. We present how magnetic ring was designed, type of magnetization used and how we solved the problem with high speed. A block diagram of the electronics and the function of software code is also explained. The third part presents hardware and software used for this project, how to simulate a real controller for encoder testing and a presentation of the testing device. In the last part of the thesis we describe the final implementation of the encoder, some of the main tests performed, the problems we faced and how they were resolved.

• Keywords: rotary magnetic position encoder, Hall sensor, AMR sensor, interpolator, magnetic principle