基于磁传感器阵列的目标跟踪定位技术

Dissertation for the Master Degree in Engineering
DESIGN OF THE MAGNETIC LOCALIZATION AND ORIENTATION SYSTEM BASED ON MAGNETIC SENSOR ARRAY
Candidate： Supervisor： Academic Degree Applied for： Speciality： Affiliation： Date of Defence： Degree-Conferring-Institution：
硕士学位论文
基于磁传感器阵列的目标 跟踪定位技术
DESIGN OF THE MAGNETIC LOCALIZATION AND ORIENTATION SYSTEM BASED ON MAGNETIC SENSOR ARRAY
杨琳
哈尔滨工业大学 2010 年 12 月
国内图书分类号：TN46 国际图书分类号：620.39
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பைடு நூலகம்
哈尔滨工业大学工学硕士学位论文
Abstract
With the development of science and technology in medical field, the patient's pain is constantly reduced. Gastroenterology doctors can use gastrointestinal tract micro-clinic robot to check the patient's gastrointestinal illness. Gastrointestinal tract micro-robot is a small clinic, wireless medical devices, such as the very popular wireless capsule endoscope, which the patient can take like taking ordinary capsule, and which can go into the human’s body to sample digestive liquid, release the pills at the suitable location and take pictures in the Gastrointestinal tract . It really release noninvasive and minimally invasive medical treatment concept. When the gastrointestinal tract micro-robot goes into the human body, it is a meaningful research to locate it outside the human body and get its trajectory. Nowadays, there are many localization methods, for instance, nuclear medicine image localization method, ultrasound localization method, the RF signal localization method, AC excitation localization method, magnetic marker localization method and electromagnetic localization method. The disadvantage of the nuclear medicine image localization method is high radiation; the ultrasound, the RF signal and the AC excitation localization method are low accuracy and high complex structure; the magnetic marker and the electromagnetic localization method is high cost. Since the disadvantages of the above localization methods, a magnetic localization method will be proposed in this article. Because the human body’s permeability is very close to that of the air, water or other non-ferromagnetic material, and non-ferromagnetic material has little effect on static magnetic field, so the magnetic localization accuracy will be high, no radiation to the human body, and low achievement cost. Magnetic localization method will fix the permanent magnet inside the micro-robot, and in order to locate the permanent magnet, the magnetic sensor array module will be developed outside the human body. 80 sensors will be evenly distributed in one cubic meter of space; the sensor array is to sample the magnetic data of the permanent magnet; according to the strength level of the magnetic signal, the magnetic signals will be converted to the corresponding electrical signals with different amplitude s by sensor array; the sampled electrical signals will be transmitted via multiple channels to data processing module, where they will be amplified and AD converted; then they will be transmitted to the computer through the serial port; the computer is to filter the data and calculate magnet’s position on the basis of the magnetic dipole model using L-M algorithm. In order to display the trajectory of permanent magnet and location information in real-time, a graphical user interface is developed with Visual C++ Software.
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哈尔滨工业大学工学硕士学位论文
In the localization process, the sensitivity of magnetic sensors has nonlinear characteristics, there is a deviation between the center position of the magnetic sensor and the prescriptive position, and there is noise mixed with the sampled data. To solve these problems, sensitivity nonlinear calibration algorithm, the center of the magnetic sensor position and orientation calibration algorithm will be applied on the magnetic localization and orientation system for data processing to provide high localization accuracy. Research and experimental results show that the design localization and orientation system based on magnetic sensor is correct and the laboratory equipment is possible. Through repeated accuracy measurement, the average localization accuracy is within 2 mm and the average orientation accuracy is within 2 degrees. Keywords: magnetic localization, magnetic dipole model, L-M algorithm, accuracy calibration
哈尔滨工业大学工学硕士学位论文
摘
要
随着科学技术在医疗领域的发展，病人的痛苦在不断地减轻。肠胃科医生可以 使用消化道微型诊疗机器人来检查病人的肠胃道病况。消化道微型诊疗机器人是一 种体积小、无线的医疗器械，例如目前很流行的无线胶囊内窥镜，病人可以像服用 普通胶囊一样服用无线胶囊内窥镜，内窥镜进入人体可以采集消化道液、定位释放 药丸以及拍摄消化道的图片。真正实现无创、微创的医疗理念。 当消化道微型诊疗机器人进入人体内，在人体外对它的位置进行定位，以及准 确掌握它的运动轨迹是一项很有意义的研究。目前常见的定位方法有核医学图像定 位法、超声定位法、射频信号定位法、交流激磁定位法、磁标记物定位法和电磁定 位法。核医学图像定位法的缺点是具有高辐射性；超声定位法、射频信号定位法和 交流激磁定位法的缺点是定位精度低并且实现模型复杂；磁标记物定位法和电磁定 位法的缺点是成本高。 基于以上定位方法的缺点， 本文中提出磁定位方法。 由于人体的磁导率与空气， 水或者其它非铁磁性物质的磁导率很接近，而非铁磁性物质对于静磁场几乎没有影 响，因此磁定位方法的定位精度会很高，而且对人体没有辐射性，实现成本低。磁 定位方法是将永磁铁固定在微型诊疗机器人内，为了定位永磁铁，在人体外研制了 磁传感器阵列模块。将 80 个传感器均匀分布在 1 m3 的空间中，由传感器采集永磁 铁的磁场数据，磁传感器根据磁场信号的强弱转化成幅值不同的电信号；采集来的 电信号经由多通道传送至数据处理模块进行放大、AD 转换；通过串口将处理后的 数据传送给计算机；计算机对数据进行滤波，并使用 Levenberg-Marquardt(L-M)算 法求解磁偶极子模型，以获得永磁铁位置信息。用 Visual C++软件开发用户图形界 面，实时显示永磁铁的运动轨迹和位置信息。 在定位过程中，由于磁传感器的灵敏度具有非线性特性、磁传感器的中心位置 和方向与所规定的位置和方向有偏差，而且传感器采集来的数据中混有噪声，针对 这些问题对定位系统采用灵敏度非线性校准算法、磁传感器的中心位置和方向的校 准算法进行数据处理，提高定位精度。 研究和实验结果表明，基于磁传感器阵列的目标跟踪定位技术方案正确，实验 装置可行， 重复测量定位精度， 位置平均定位精度是 2mm， 方向平均定位精度是 2 。 关键词：磁定位；磁偶极子模型；Levenberg-Marquardt算法；精度校准