针对空间光学镜指向机构高精度、轻量化的特殊要求, 提出一种基于球面5R机构的新型空间二维并联指向机构。传统球面5R并联机构存在负载不便安装的问题, 通过设计非对称支链形式和特殊连杆结构, 有效解决了这一问题。基于机构的运动学分析, 以工作空间、灵巧性和承载能力作为优化指标, 采用图谱法对机构的结构参数进行了优化设计。采用有限元方法对优化后机构的不同负载布置形式进行模态分析。优化结果表明非对称支链形式机构具有更好的灵巧性指标。设计光学镜负载质心位于球面机构球心处, 结构更加紧凑, 可以提高机构固有频率, 并且能够降低负载运动转动惯量。提出的新型空间光学镜并联指向机构具有良好的综合性能, 研究为高精度并联光学指向机构的应用提供了理论基础。

To meet the high-precision and lightweight requirements of a space optical mirror pointing mechanism, a type of space parallel mechanism based on a spherical 5R mechanism was proposed. Load mounting with traditional 5R parallel mechanisms was difficult. To solve this problem, asymmetrical branches and specific linkages were designed. Workspace, dexterity and carrying capacity were used as optimal indices, and structural parameter optimization design was conducted based on performance atlases. Model analysis of the optimized mechanism was conducted by using the finite element method. Optimization results show that the asymmetrical branched-chain mechanism has a better index of dexterity. The barycenter of the pointing mirror load was designed at the center of the spherical mechanism, which makes the mechanism more compact and increases its natural frequency. The proposed parallel pointing mechanism was shown to have good integrated performance. This study provides a basis for high-precision space optical pointing applications.