Magnetic Tracking System with Capability of Automatic Magnetic Moment Measurement

doi:10.1007/s12204-024-2720-5

Abstract

Abstract: Magnetic tracking technologies have a promising application in detecting the real-time position and attitude of a capsule endoscope. However, most of them need to measure the magnetic moment of a permanent magnet (PM) embedded in the capsule accurately in advance, which can cause inconvenience to practical application. To solve this problem, this paper proposes a magnetic tracking system with the capability of measuring the magnetic moment of the PM automatically. The system is constructed based on a 4 × 4 magnetic sensor array, whose sensing data is analyzed to determine the magnetic moment by referring to a magnetic dipole model. With the determined magnetic moment, a method of fusing the linear calculation and Levenberg-Marquardt algorithms is proposed to determine the 3D position and 2D attitude of the PM. The experiments verified that the proposed system can achieve localization errors of 0.48mm, 0.42mm, and 0.83mm and orientation errors of 0.66 ◦ , 0.64 ◦ , and 0.87◦ for a PM (∅10mm × 10mm) at vertical heights of 5 cm, 10 cm, and 15 cm from the magnetic sensor array, respectively.

Key words: permanent magnet, magnetic moment measurement, optimized Levenberg-Marquardt algorithm, MAG3110 magnetic sensor, tracking system

摘要： 磁跟踪技术在检测胶囊内窥镜的实时位置和姿态方面有着广阔的应用前景。然而，它们大多需要提前精确测量嵌入胶囊中的永磁体的磁矩，这会给实际应用带来不便。为了解决这个问题，提出了一种能够自动测量永磁体磁矩的磁跟踪系统。该系统以4×4的磁传感器阵列为基础，参照磁偶极子模型分析其传感数据来确定磁矩。利用确定的磁矩，提出了一种融合线性计算和 Levenberg-Marquardt算法的方法，以确定永磁体的三维位置和二维姿态。实验证明，对于距离磁传感器阵列垂直高度分别为 5 cm、10 cm和 15 cm的永磁体（Ø10 mm × 10 mm），所提出的系统可实现的定位误差分别为0.48 mm、0.42 mm和 0.83 mm，定向误差分别为0.66°、0.64°和 0.87°。

关键词: 永磁体，磁矩测量，优化Levenberg-Marquardt算法，MAG3110磁传感器，跟踪系统

CLC Number:

R57
TM936

Tian Siyu, Gao Jinyang, Huang Peng, Ma Xinyu, Ma Ziyu. Magnetic Tracking System with Capability of Automatic Magnetic Moment Measurement[J]. J Shanghai Jiaotong Univ Sci, 2025, 30(4): 646-657.

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