磁性編碼器充磁座之磁路模擬與分析

The magnetic-circuit simulation and analysis for a fixture of the magnetic encoder

簡志榮(Zing-Rong Jian)

指導教授 ： 劉宗平

元智大學/工程學院/電機工程學系/碩士(2001年)

摘要

目前，編碼器已經被廣泛地應用在各類精密微小型馬達中，可作為位置與速度的高精密量測元件。磁性編碼器，因其構造簡單、耐震性強且不受灰塵、濕氣等的影響，現在已逐漸地取代光學式編碼器。然而，磁性編碼器的解析度尚不及光學式編碼器，為了磁性編碼器可滿足伺服馬達機構中所要求的解析度，因而當將磁性編碼器內的磁環充磁時，其極間距必須儘可能地縮小,以使得可充磁的極數增加。因此，本研究採用一種旋轉式多極充磁機來進行充磁，以達到上述的要求。
一般而言，磁環充磁的技術會嚴重影響磁性編碼器的性能，因此其充磁條件如充磁電流、充磁頭之形狀、以及氣隙等項，都必須要仔細地考慮與掌握。為此，本研究採用有限元素法構建整個磁路模擬所需之網格模型，以差分計算的方法模擬實際充磁的情形。經由磁路分析的技巧，探討充磁過程中可茲調整的參數。
藉由參數的變化，找出主導磁路的參數，以及它們對充磁頭與磁環充磁時所造成的影響。同時，本研究也實際地利用旋轉式充磁機對磁環進行充磁量測，並檢測磁環充磁完畢後之表現。經充磁量測分析後，發現多極充磁之效果大體上符合初步的預期。

關鍵字

磁性編碼器 ； 磁路模擬 ； 充磁座

並列摘要

Up to date, encoders have widely used in various micro-motors to detect their position or rotational speed accurately. Since the structure of a magnetic rotary encoder is very simple and that is not affected in dust, mist, and oil. Then it is gradually used to replace the optical encoder of a servomotor. However, the resolution of a magnetic encoder is not so good as that of an optical encoder. When the magnetic drum was magnetized the required pole pitch is needed very small in size, in order to satisfy the requirements of the resolution in a servomotor. Therefore, we use a type of rotary multi-pole magnetization method to magnetizing the drum in the study.
Generally speaking, the techniques of magnetization affect the quality of magnetic encoder seriously. Therefore, the magnetizing conditions, for example magnetizing currents, the shape of the magnetizing head, and the gap must be thought and controlled in detail. In the study, we use finite element method to establish the mesh of the model needed for the magnetic-circuit. And we use differential calculus method to simulate the performance of the magnetization. Through the skill of the magnetic—circuit analysis, we discuss the variable parameters in the magnetizing process.
According to the changes of the parameters, we find parameters of leading the magnetic-circuit, and how do the parameters affect the magnetic head and drum during the magnetization. At the same time, we actually use the rotary magnetizing machine to magnetize measure and detect the display of the drum. After analysis, we find that the results of the multi-pole magnetization fit in with our expected.

並列關鍵字

magnetic encoder ； magnetic-circuit simulation ； fixture

參考文獻

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