Gong Junqiang, Liu Dameng, Luo Jianbin
State Key Laboratory of Tribology in Advanced Equipment, Tsinghua University, Beijing 100084, China.
Union Optech Co., Ltd., Zhongshan 528463, China.
Sensors (Basel). 2025 Mar 14;25(6):1820. doi: 10.3390/s25061820.
In response to the accurate positioning issue for high-speed moving lens groups in rapid zoom optical lenses with voice coil motors (VCMs), we demonstrate a positioning system design based on tunnel magnetoresistance sensors. The equivalent magnetic charge method and finite element method (FEM) simulations were utilized to compute the magnetic field distribution of the magnetic grating encoder. Based on analytical computation, the optimal air gap between the sensor and magnetic grating is determined to be = 0.15 mm, which balances magnetic flux density amplitude and total harmonic distortion. In addition, a simplified fitting model is proposed to reduce computational complexity. We quantify the magnetic interference of VCM through three-dimensional flux leakage mapping by FEM analysis, deriving an optimal sensor position , with a 24 mm -offset and 20 mm -offset relative to the VCM's origin . The position error caused by interference remains below 5 μm with maximum deviations at trajectory endpoints of the moving group. The original signal output is processed and corrected, and eventually, the measured displacement exhibits a linear relationship with actual displacement. Our study provides a comprehensive framework for the design and optimization of magnetic positioning systems in optical applications with electromagnetic motors.
针对采用音圈电机（VCM）的快速变焦光学镜头中高速移动镜头组的精确定位问题，我们展示了一种基于隧道磁阻传感器的定位系统设计。利用等效磁荷法和有限元方法（FEM）模拟来计算磁光栅编码器的磁场分布。基于解析计算，确定传感器与磁光栅之间的最佳气隙为 = 0.15 mm，这平衡了磁通密度幅度和总谐波失真。此外，提出了一种简化的拟合模型以降低计算复杂度。我们通过有限元分析的三维磁通泄漏映射来量化VCM的磁干扰，得出相对于VCM原点 具有24 mm偏移和20 mm偏移的最佳传感器位置 。由干扰引起的位置误差在移动组轨迹端点处的最大偏差情况下仍保持在5μm以下。对原始信号输出进行处理和校正，最终，测量位移与实际位移呈现线性关系。我们的研究为电磁电机光学应用中的磁定位系统设计和优化提供了一个全面的框架。
