多环闭链空间可展开机构力-热耦合协同优化

Collaborative optimization based on thermo-mechanical coupling of the multi-closed-loop space deployable mechanism

针对一种多环闭链空间可展开机构的力-热耦合设计问题,首先列写了展开单元机构的静力学平衡方程,完成了展开单元的静力学分析,进而根据虚功原理,求得机构在展开态下的转动刚度;然后综合考虑机构的力热性能,以杆件横截面尺寸为设计变量,以机构在太空环境下整个展开过程中的热变形小、重量轻、展开态下的基频高和转动刚度大作为优化目标,采用协同优化方法建立了多环闭链空间可展开机构协同优化的数学模型;通过数值求解,得到该机构所有杆件的横截面尺寸参数最优值.分析结果表明,优化后的机构热变形降低了约56%,展开态基频提高了约39%,展开单元的重量与转动刚度均满足设计指标.

In order to address the thermo-mechanical coupling design of a multi-closed-loop space deployable mechanism, the static equilibrium equation is derived and a static analysis is made. The rotational stiffness of the mechanism in the deployed phase is obtained according to the principle of virtual work. Then, for improving the mechanical and thermal properties, the mathematical model of collaborative optimization considering thermo-mechanical coupling is established, of which the design variables are the size of bar cross section, and the objective functions include the minimal thermal deformation of the structure during the entire deployment in the space environment, the minimum weight, the maximum basic frequency and rotational stiffness in the deployed phase. By the numerical solution of the collaborative optimization model of the multi-closed-loop space deployable mechanism, the optimum rod section parameters of the deployable mechanism can be obtained. Simulation results show that the thermal deformation reduces by 56~, that the basic frequency increases by 39%, and that the mass and rotational stiffness also meet their design goals.