An Absolute Position Detection Method for PMLSM Based on Magnetoresistive Effect

Modern flexible production lines and intelligent logistics systems require position sensing solutions that support long travel ranges, high accuracy, cable-free operation, and minimal structural constraints. Conventional high-precision encoders, such as optical gratings, suffer from high cost and limited range, while magnetic encoders are typically restricted to short-travel applications and constrained by cable connections. This paper presents a long-range absolute position sensing method based on an anisotropic magnetoresistance (AMR) sensor array. A primary sensor index is first identified to locate the position within a specific magnetic period. Then, the actual position is reconstructed using an arctangent algorithm applied to the sinusoidal output signals. To address position discontinuities caused by magnetic field distortions near array edges, a compensation algorithm is proposed to ensure continuity and accuracy of the absolute position output. Experimental results validate the effectiveness of the method, demonstrating high accuracy over long travel distances, as well as suitability for cable-free and structurally flexible industrial applications.