六自由度电磁定位跟踪系统

发布时间：2017-12-30 19:06

本文关键词：六自由度电磁定位跟踪系统　出处：《天津大学》2012年硕士论文　论文类型：学位论文

【摘要】：六自由度电磁跟踪系统作为定位装置被广泛应用于增强现实、便携式激光扫描仪、计算机辅助医疗系统、微创手术、医学教学、医学图像等领域。随着定位技术的发展，人们与计算机之间的沟通也变得更加灵活。电磁跟踪系统因为无遮挡、灵活等优点较之其他定位系统使用更加广泛。本文设计一个电磁跟踪系统，提出交变方波驱动信号，实时的除去涡流。文中进一步改进了定位算法。本文对比圆形线圈模型与正方形线圈模型磁场，进一步证明方形线圈可近似为磁偶极子，并分析了方形线圈随距离变化的误差变化。用Ansoft Maxwell有限元分析软件对线圈进行仿真，得出线圈的电流、磁场分布和矢量图、关键点处的磁场情况，为跟踪系统提供理论基础。对比欧拉角法和四元数法，并分析了基于各向异性参数的欧拉角法和四元数法。基于各向异性参数模型，采用了同时求解位置和姿态参数的四元数法，简化求解步骤，减小求解时间。对电磁跟踪系统硬件进行设计，包括发射线圈及信号的产生、驱动电路、微控制器、接收传感器、放大电路、A/D转换电路。其中在发射线圈的设计中，对比了有磁芯线圈与空心线圈的异同，，确定空心线圈发射方案。结合接收传感器和发射信号的特点，计算最终接收值。最后给出实验数据和示波器其所接收到的波形图，并给出三种方法的算法流程图，并对比分析几种算法的计算结果。本文提出的交变方波驱动信号，使系统能实时减去外界干扰磁场与地磁场的干扰，更能有效地除去外界变化磁场的干扰。对线圈模型分析，并对其进行建模仿真，为电磁跟踪系统提供理论支撑。
[Abstract]:Six degree of freedom electromagnetic tracking system as the positioning device is widely used in augmented reality, portable laser scanner, computer aided medical system, minimally invasive surgery, medical teaching, the field of medical image. With the development of location technology, the communication between people and computer has become more flexible. The electromagnetic tracking system because of the advantages of flexible with no shelter, the other positioning system is more widely used. The design of an electromagnetic tracking system in this paper, the square wave drive signal in real time. The removal of eddy current to further improve the positioning algorithm.
This paper compared the circular coil model and square coil model for the magnetic field, further proof of square coil can be approximated as magnetic dipole, and analyzes the error of distance change with square coil change. The simulation of coil with Ansoft finite element analysis software Maxwell, the coil current, magnetic field and magnetic field vector diagram, the key points, provide the theoretical foundation for the tracking system.
The Euler angle method and the four element number method are compared. The Euler angle method and the four element number method based on the anisotropic parameter are analyzed. Based on the anisotropic parameter model, the four element method is used to solve the position and attitude parameters simultaneously, which simplifies the solving steps and reduces the solving time.
The electromagnetic tracking system hardware design, including the transmitting coil and signal generation, drive circuit, micro controller, sensor, amplifier circuit, A/D conversion circuit. In the design of the transmitting coil, compared with a magnetic core coil and the hollow coil, determine the hollow coil launch scheme. According to the characteristics of sensor and signal receiving the calculation of the final value received.
Finally, the experimental data and the oscillograph received by the oscilloscope are given, and the algorithm flow chart of the three methods is given, and the calculation results of several algorithms are compared and analyzed.
The alternating square wave driving signal proposed in this paper can make the system subtract the interference from external interference magnetic field and geomagnetic field in real time, and effectively remove the interference of external magnetic field. Analyze and model the coil model, and provide theoretical support for electromagnetic tracking system.

【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：R312

【引证文献】