增量式磁性編碼器類比訊號為正弦與餘弦訊號，其誤差包含直流偏移、振幅不等、相位偏移、諧波誤差。現今對於前三種誤差已有許多處理方式，但大多數方法僅針對固定量值進行修正。在訊號誤差隨使用情況而改變的情境下，需要一套能夠即時修正訊號的方法。除這三種誤差之外，磁性編碼器訊號中常有諧波的成份出現，此特徵主要來自於磁性尺提供的磁場與異向性磁阻感測器的形狀異向性。
本研究提出新的自適應演算法對前三項誤差進行即時的量值估計與消除。此方法在演算法中加入虛擬的量測數據，以避免系統在停止運動時出現估計錯誤的現象。對於訊號中諧波成份，選用訊號交錯時的量值以估計誤差，在特定範圍內使用同樣的數值進行修正。藉本文所提之訊號修正方案，編碼器位置諧波誤差平均振幅可降低至0.5 μm以下。

The incremental magnetic encoder outputs quadrature signals with error components, these errors include DC offset, unequal gain, phase shift, and harmonic error. Nowadays, there are many ways to correct the first three types of errors by assuming that each error is constant. However, the signal errors vary with the environmental change. Hence, an algorithm that can track the signal errors in real-time is required. Besides the first three errors, the signals contain the harmonic error, which results from the harmonic magnetic field and the shape anisotropic of the anisotropic magnetoresistance (AMR) sensor.
This study proposes a new adaptive algorithm to estimate and then eliminate the magnitude of the first three errors. Virtual points are added to measurement data to prevent estimation errors when the motion of the system stops. The harmonic error is estimated with the magnitudes of the signals at crossingpoints, and is corrected with the same value at a certain range. With the proposed correction method, the average magnitude of harmonic component of position error reduces to below 0.5 μm.

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