TMT三镜系统Rotator组件结构技术研究

	TMT三镜系统Rotator组件结构技术研究
	苏燕芹
学位类型	博士
导师	张景旭
	2014-07
学位授予单位	中国科学院大学
学位专业	机械制造及其自动化
摘要	TMT三镜系统不同于其他望远镜，其奈氏平台上有多个科学仪器，有的仪器不在望远镜的俯仰轴上。当不在望远镜俯仰轴上的仪器工作时，三镜系统需要转动一定的角度将光线反射到该仪器中。这个角度随望远镜观测方位的变化而变化，所以三镜系统需要具备跟踪和瞄准功能，随着望远镜俯仰的变化而转动，从而导致复杂的运动状态和载荷工况。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，同时对Rotator组件和三镜系统的性能进行了初步分析。论文包括以下主要内容： (1) 总结了现有的大口径望远镜方位轴系技术方案。 (2) 结合三镜系统的具体特点，从轴系支撑方式、驱动方式和测角方案三个方面展开研究。通过建立大型回转支承的数学模型，计算得到不同形式轴承在不同天顶角下的承载性能；根据设计需要，采用双电机驱动的方式，对双电机驱动的原理进行了研究，设计了双电机驱动的结构形式，并对双电机消隙的控制效果进行了仿真，利用蒙特卡洛方法估计了齿轮传动误差；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，并对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开展了试验验证。 (3) 对Rotator组件中的关键部件进行了优化设计，在保证刚度的前提下，使其质量分布更合理。由于三镜系统和塔台的接口精度和刚度直接关系到三镜系统的工作性能，提出了运动学接口和非运动学接口两种形式，通过评估不同形式的接口对Rotator组件轴承安装平面的影响，最终确定了非运动学接口形式,并分析Rotator组件的回转精度。 (4) 分析了Rotator组件自身的静态和动态特性。由于需要关注Rotator组件在三镜系统中的性能，所以对三镜系统整体也进行了有限元分析，对三镜系统在不同天顶角下的系统刚度和应力进行了校核，分析了三镜系统的静、动态特性。根据环境适应的要求，本文重点关注了三镜系统抵抗一定强度地震载荷的能力，得到了其在不同强度和方向的地震载荷下的响应，并提出了相应的地震防护措施。最后，对三镜系统抵抗风载荷的能力进行了研究。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，较好的满足了三镜系统的需要。为了估计Rotator组件在三镜系统的性能，对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。文中的一些结论可适用于一般的大口径望远镜设计。
其他摘要	TMT Tertiary Mirror System (M3S) is different from other telescopes. There are many instruments on Nasmyth platforms both sides, some are not located on elevation axis. When the instrument that does not locate on elevation axis is working, M3S should rotate in angles to reflect light ray to the instrument. The rotating angle varies following the telescope position. M3S should be capable of pointing and tracking, rotating with the observing position, which results in complicated load cases. In this article, Rotator assembly is designed according to M3S design requirement, and key techniques involved in Rotator are studied. At last, performance of Rotator and M3S are analyzed. The mains points are as following: (1) The azimuth axes schemes of present large aperture telescopes are summed up after looking up plenty of documents. (2) Researches are developed on supporting scheme, driving scheme and position measurement on the basis of M3S characters. The mathematical models of different types of bearings are built, and the performance under different zenith angles is obtained. Dual-motor driving scheme are adopted to satisfy the requirements of structure. Dual-motor driving principle is studied, and the driving structure is designed, the control results are simulated. Gear transmission error is evaluated by Monte-Carlo method. Because of the large diameter, a tape encoder is adopted, the accuracy and usage of the encoder are explored. A test were carried out to check the effect of four readheads and Fourier harmonic analysis to improving angle measurement accuracy. (3) Key components of Rotator are optimized, the mass distribution is more reasonable. As the interface between M3S and tower would affect the M3S performance, kinematic interface and non-kinematic interface are put forward. After evaluation, the non-kinematic interface affects less to the bearing mounting surface than non-kinematic, so the former is confirmed. The axes accuracy are discussed. (4) The static and dynamic performance of Rotator are analyzed by Finite Element Analysis (FEA). As the performance of Rotator when it is assembled to M3S is more important, the FEA is also done to M3S when the system is under different zenith angles. The deformation and stress response are acquired. As TMT observatory is a seismic zone, the ability of M3S to resist certain intensity earthquakes are analyzed. The protection means are discussed too. At last, the structure response to wind is simulated. In this article, some key techniques involved in azimuth axes are studied on the basic of TMT M3S design. Performance of the system under different zenith angles are evaluated sufficiently, that would be very helpful guidance to M3S design. Some conclusions can be applied to general large telescope design.
语种	中文
文献类型	学位论文
条目标识符	http://ir.ciomp.ac.cn/handle/181722/41466
专题	中科院长春光机所知识产出
推荐引用方式 GB/T 7714	苏燕芹. TMT三镜系统Rotator组件结构技术研究[D]. 中国科学院大学,2014.

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