【作者】 苏燕芹；

【导师】 张景旭；

【作者基本信息】 中国科学院研究生院(长春光学精密机械与物理研究所) ， 机械制造及其自动化， 2014， 博士

【摘要】 TMT(Thirty Meter Telescope)三镜系统不同于其他望远镜，要求具有跟踪和瞄准功能。三镜系统与地平式望远镜不同，其工况复杂且载荷变化为非线性，保证复杂工况下轴系的高精度是本文面临的主要难点。本文从TMT三镜系统的要求出发，对其中的Rotator组件进行了设计，并对涉及的关键技术进行了研究，同时，通过大量的仿真分析保证系统性能符合设计要求。为了满足轴系的高精度要求，本文从方案选择、静态性能、动态性能和接口精度四个方面保证系统满足精度要求，主要包括以下内容：(1)分别对轴系的支承方式、驱动方案和测角方案进行了研究。采用数学建模的方法，建立了不同类型大型回转轴承在复杂载荷下的承载数学模型，计算得到轴承的轴向变形、径向变形和角变形量，对轴承的承载性能进行了评价。通过对不同类型望远镜驱动方式的比较，选择了齿轮驱动的方案，研究了双电机驱动的原理，并仿真分析了系统的快速性和稳态跟踪性能，结果表明可满足系统的跟踪精度要求。由于钢环编码器不能满足系统要求，本文采用钢带编码器，对其精度、使用方法进行了研究，并验证了多读数头结合傅里叶谐波分析方法提高转台测角精度的有效性。通过对每部分方案的合理选择，轴系的性能得到了极大了优化。(2)为了对Rotator组件自身的性能进行评估，建立了系统的有限元模型，对关键部件的建模方法进行了研究，仿真分析了该组件的静、动态性能。同时，为了对三镜系统进行性能评估，建立了整个系统的有限元模型，并对其在重力作用下的性能进行了分析计算，保证系统在工作时的可靠性。整个系统的一阶固有频率为15.93Hz,满足了系统的模态特性要求。(3)支撑塔台的变形会影响三镜系统的工作性能,所以需要对三镜系统与塔台之间的连接方式进行研究。本文提出了两种方法,一种基于运动学原理,提出了六点支撑结合球形垫片调整的方法；另一种为非运动学连接。为了对两种方案进行评价,分别计算了对轴承安装平面的面形精度的影响,结果表明后者的精度较高,且能够满足轴承安装面的平面度为0.02mm的要求。另外,三镜系统的环境适应性是设计的又一重要指标。针对地震分析,本文采用谱分析的方法,分析了三镜系统在不同等级地震载荷下的响应；针对风载荷,分别采用流固耦合和随机振动的方法对静态和动态风载下结构的响应进行了仿真分析。本文基于TMT三镜系统的研制,对Rotator组件中涉及的一些关键技术进行研究。对Rotator组件和三镜系统整体开展了大量的分析仿真,预测了系统在不同状态、不同载荷下的性能,有效指导了三镜系统的设计工作。文中的一些方法和结论对大口径望远镜设计有一定的参考价值。更多还原

【Abstract】 Thirty Meter Telescope (TMT) Tertiary Mirror System (M3S) is different fromother telescopes in requiring tracking and pointing capability. The M3S featurescomplex and nonlinear load conditions compared to the alt-azimuth telescope. Themajor challenge is to ensure the high-precision of the axes. According to therequirements of TMT, this article majors on investigating the Rotator Assemblydesign and the key technologies involved in the system. Furthermore, large numbersof simulation analysis are applied to predict and ensure the system performances.In order to meet the requirements of high-precision, the investigation in thispaper is developed from four aspects, namely scheme selection, static performance,dynamic performance and interface accuracy. The work can be described as follows:(1) Supporting way, driving scheme and angle measurement method of the axesare studied, respectively. Different kinds of slewing bearings are evaluated byestablishing the bearing mathematical models under complex load conditions, whichmakes an evaluation of bearing performance. The gear driving scheme is applied inRotator and the dual-motor driving principle is analyzed. Moreover, the fast andsteady tracking performance is simulated, which shows the system can meet therequirements of tracking accuracy. Since the round encoder cannot meet thedemands, the tape encoder is selected. The precision and using method areresearched. The result verifies the effectiveness of improving the angle measurement accuracy of the turntable by applying the multiple reading heads combing withFourier harmonic analysis. With reasonable choices of the schemes, the axesperformance has been optimized greatly.(2) In order to evaluate the performance of Rotator, the finite element model(FEM) of the system is established, some static and dynamic performance isanalyzed by simulation. Meanwhile, in order to evaluate the performance of M3S,the FEM of the whole system is established as well, and the performance undergravity is analyzed to ensure the system’s safety. The finite element analysis resultshows that the first order natural frequency of the system is15.93Hz, which canmeet the requirements of the system modal characteristics.(3) As the supporting tower’s deformation would affect the M3S performance,it is necessary to investigate the connection methods between M3S and the tower.Two methods are proposed, one is kinematic connection method, and the other isnon-kinematic. The impacts on the accuracy of the bearing mounting surface arecalculated, respectively. The results indicate that the latter can get a higher precision,and meet the requirement of0.02mm of the bearing mounting surface flatness.In addition, environmental adaptability of the M3S is another important index.For seismic analysis, the spectral analysis method is applied to analyze the systemresponse under different levels of seismic loads. For wind loads analysis, thefluid-structure interaction and random vibration methods are used for structureresponse under static and dynamic wind loads, respectively.This paper has researched some key technologies of Rotator. A mount ofsimulation analysis of Rotator and M3S are carried out to predict the performance ofthe system in different working states, which effectively guides the design of M3S.Some of the methods and conclusions involved in this paper have a certain referencevalue on the large telescope design.更多还原