中文摘要：

TMT（Thirty Meter Telescope）望远镜是一台R—C式的30m17径光学红外望远镜，其三镜为椭圆形平面镜，口径为3．5940mx2．568m，质量达到1．8t，三镜系统需要把来自次镜的光折转到望远镜两侧耐氏平台上的一系列科学仪器上，具有跟踪和快速定向功能。支撑系统包括底支撑系统和侧支撑系统，根据TMT对三镜的面形要求，提出了底支撑系统采用18点Whiffletree结构，通过优化分析，面形RMS值达到118．5nm。针对侧支撑系统，提出了基于kinematics原理的12点支撑方式，侧支撑作用下的面形RMS值为4．7nm，两者综合作用下的面形RMS值优于77nm。按照支撑系统方案，设计了一种满足一定质量和体积要求的支撑系统结构。

英文摘要：

TMT （Thirty Meter Telescope） was a Ritchey Chretien optical-infrared thirty meter telescope with 3.594 m×2.568 m ellipse flat one and 1 800 kg weight. The tertiary mirror system reflected the light coming from the secondary mirror （M2S） to the science instruments which mounted on the telescope Nasmyth platforms. It had tracking and slewing functions. Tertiary mirror support system included axial support system and lateral support system. Based on the mirror surface figure error requirements, the paper proposed axial support system used 18 point whiffletree structure with surface figure RMS of 118.5nm after optimum. The surface figure RMS can reach 4.7 nm by the lateral support, and the surface figure RMS was less than 77 nm by axial and lateral support. Based on this support program, the mirror support structure is designed to satisfy weighted and volume requirements.