【作者】 胡盛勇；

【导师】 郑津津；

【作者基本信息】 中国科学技术大学 ， 精密仪器及机械， 2011， 博士

【摘要】 本论文对一种悬线带5°夹角的三维悬线式蓝光光学头力矩器进行了磁场分析、模态和谐响应分析,通过与实验对比建立三维悬线式蓝光光学头力矩器的磁场、低频特性参数的仿真计算模型,同时对力矩器等效刚度模型和灵敏度方面等参数进行理论探讨和优化。首先介绍光学头系统组成以及力矩器实现聚焦运动和循迹运动的控制原理。力矩器作为光存储读取系统光学头中最重要的部件之一,其性能的好坏决定着整个读取头的好坏。随着光存储的发展,特别是蓝光存储的出现传统的二维悬线式力矩器已经不能满足需要,三维悬线式力矩器则成为新的发展方向。在国内对于力矩器的研究还停留着二维力矩器上,而新的三维悬线式力矩器则国内还处于空白。三维悬线式力矩器相对于二维力矩器具有更复杂的结构和更高的灵敏度,其结构尺寸也越来越小,因此具有很高的研究价值。力矩器的两个主要运动:聚焦运动和循迹运动是力矩器最主要的方向上的参数,两个方向上的特性参数和实验测试方法以及光学光学头实现聚焦运动和循迹运动的原理都进行了测量和介绍。利用有限元软件ANSYS的磁场分析模块,建立了三维悬线式蓝光光学头力矩器的磁场分析模型。三维悬线式力矩器实现聚焦运动、聚焦运动和倾斜补偿运动是通过磁场中的通电线圈受力来实现的。对力矩器的磁场分布建立理论模型,永磁铁磁场模型采用磁极化理论来建立,而毕奥-萨伐尔定律来建立通电线圈的磁场模型。利用有限元软件ANSYS中的电磁场模块,对线圈实体建模,并把电流源以电流密度的方式输入,用矢量单元SOLID97代替标量单元,用MVP的方法求解得到力矩器线圈上的磁场分布和有效受力。建立了三维悬线式蓝光光学头力矩器的低频特性仿真分析模型。三维悬线式力矩器主要由可动部件和不可动部件组成,其中不可动部件主要包括磁铁和轭铁为磁场的主要组成部分,可动部件包括物镜架、物镜、五组线圈和六根悬线。三维悬线式力矩器在工作的时候是始终处于一种振动状态。三维悬线式力矩器的力学特性参数如一阶共振频率、一阶共振峰值、5Hz灵敏度和200Hz灵敏度等是体现力矩器性能的主要参数。利用ANSYS中的模态分析模块提取力矩器可动部件的模态。可动部件的低频区域主要为聚焦方向、循迹方向和倾斜方向上的固有频率分别50.5Hz,54.8Hz,205.2Hz,三种模态模拟结果与实验对比误差小于1%;可动部件的高频区域模态主要是物镜架组件的弹性共振,且二阶共振频率均大于20kHz。采用ANSYS软件中的谐响应模块对力矩器的特性参数进行模拟,而力矩器中的阻尼胶效应则使用等效阻尼系统来模拟,通过与实验对比仿真结果误差在5%以内。利用材料力学建立了三维悬线式蓝光光学头力矩器的等效刚度模型。根据振动原理知道六根悬线都作为理想的悬臂梁结构处理且这六根悬线为并联的方式。对每根悬线进行受力分析,采用材料力学中梁的挠度原理求解得到力矩三个方向的等效刚度模型,通过与实验结果对比误差在5%以内。并对悬线的长度、半径、夹角、不同截面以及六根悬线截面的进行不同设计为力矩器的频率优化提供设计方案。采用正交试验设计做为分析方法,提取力矩器磁场的七个磁场因子对力矩器的灵敏度进行优化。对力矩器磁场因子提取七个因子,利用三水平七因子的正交表分析,发现永磁铁的位置和其磁极方向对力矩器的灵敏度有较大的影响可以提高接近40%,为力矩器的灵敏度设计提供了设计基础。更多还原

【Abstract】 In this dissertation, a 3-axis 5°wire-angle optical head actuator has been simulated by using magnetic analysis, model analysis and harmonic analysis, and the 3-axis BD actuator simulating model is built after comparing the emulated results with the experiments, and also the effective stiffness model and the sensitivity of the actuator has been carried out for theory investigation and optimization.Firstly, the rules of focusing and tracking of optical actuator and the components of optical head are introduced. The actuator is one of the most components of the optical head in optical storage, and the characteristics of actuator determine the capability of the optical head. Along with the development of optical storage, the conventional 2-axis optical wire actuator can’t meet with the needs after the invention of BD storage, and the 3-axie optical wire actuator is for the new challenge. The civil research on actuator is only on 2-axis actuator, the study on 3-axis actuator is a big blank. The 3-axis actuator has more complex structure and higher sensitivity relative to 2-axis actuator, and the size of actuator is smaller, therefore, the 3-axis actuator has super research value. The main characterics of actuator are characterics of focusing direction and tracking direction, the characterics of the directions and its experiment methods as well as the principle of focusing and tracking are measured and introduced.The magnetic field analytic model of 3-axis BD optical head actuator is built. The 3-axis actuator is to achieve focus move, track move and tilt move because of the force on the coils in the magnetic fields. The theories models of the magnetic fields of actuator is built, and magnetic poralized theory is for magnet analysis, and Biot - Savart Law is for coils analysis. By using finite element method software ANSYS, structure model for coils model and the current density for current source is set up, and the magnetic fields distribution on coils and the force distribution on coils are gotten with MVP method after the vector element SOLID97 for dispersing.The low frequency characteristic analysis model of 3-axis BD actuator is achieved. The main parts of 3-axis actuator are movable part and unmovable part, among them, the unmovable part is mainly consist of magnets and the iron, and also the movable part is made up of lens, frame of lens, five groups of coils and six hanging wires. The actuator always lies to state of vibration when it works. The main characteristics of actuator are the first resonance frequency, the first resonance peak, 5Hz sensitivity, and 200Hz sensitivity and so on. so the model analysis of the software ANSYS is used to get the modes of movable part. The main modes of movable part in low frequency region are the focus mode, track mode and tilt mode, and they are 50.5Hz, 54.8Hz and 205.2Hz respectively, and the error in the three direction is less than 1% after compard with the experiment results. The modes of actuator in high region are the flexibility resonance, and the second resonance frequency of movable part is above 20 kHz. The harmonic analysis of ANSYS software is used to simulate the characteristics of actuator, and the effective damp matrix is calculated for the damping effect of actuator, and the results error of simulation is less than 5% after compared with experiment results.The effective stiffness model of 3-axis BD actuator is set up with mechanics of materials in three directions. According to vibration theory, the six hanging wires of movable part can be regarded as ideal cantilever and they are parallel joint. Through the force analysis for wires, deflection method in materials mechanics is used for solving the effective stiffness model in three directions, and the effective stiffness model is only 5% less error comparing with experiment. The length of wire, the radius of wire, the wire-angle of wire, the different sections of wire and the different sections for six wires are simulated for the first resonance frequency of actuator.The sensitivity of 3-axis BD acutaotr is optimized after selecting the seven magnetic parameters by using taguchi method. Seven parameters of magnetic fields are refined for sensitivity optimization, and the L₁₈（ 3⁷） table is set up, and the results show the distance of magnets and the polared direction are main parameter, and the sensitivity of optimization can be increased nearly 40%.更多还原