空间大口径拼接反射镜磁通钉扎连接机构的力学特性

Mechanical performance of magnetic flux-pinging mechanism in space large segmented reflect mirror

应用于空间光学系统的机械拼接机构存在润滑、热膨胀系数匹配、结构复杂、拼接偏心距小等问题,本文提出了可应用于空间大口径拼接反射镜的磁通钉扎接口方案,采用永磁体的等效电流分布模型并融合磁场法,建立了超导-永磁体磁通钉扎接口的数学模型进行仿真分析,并通过实验验证了模型的有效性。结果表明,超导体-永磁体的间隔在5 mm时,垂直连接刚度ky可达7000 N/m;当磁体-超导体的间隔为10 mm,二者处于中心位置时侧向刚度kx可达3800 N/m;磁通钉扎接口在偏心距Δx=4 mm时的垂直刚度ky相比于Δx=0时下降约20%,刚度下降不显著。相比于传统机械接口,磁通钉扎接口在反射镜对接时具备足够的连接刚度,可以允许更大的偏心距Δx,同时接口的力特性使得拼接镜在重构过程中满足缓冲定位的要求。

Mechanical connection mechanisms used in space optical systems experience problems with lubrication,thermal expansion coefficient matching,problems related to its complex structure,and small docking eccentricities.In this study,a flux-pinning interface scheme,which can be applied to a large segmented reflect mirror in space,was proposed.The mathematical model that contained the current equivalent distribution model was built and calculated by the H-formulation method,then,verification experiments were designed to demonstrate the effectiveness of the model.The relationship between the levitation force,stiffness,and relative position of the flux pinning interface under three working condition was obtained using the finite element method.The results indicate that when the distance between the superconductor and permanent magnet is 5 mm,the stiffness of the vertical direction ky can reach 7000 N/m;when the distance between the superconductor and permanent magnet is 10 mm and it is in a central position,the stiffness of the lateral direction kx can reach 3800 N/m.The stiffness of the vertical direction ky whenΔx=4 mm drops by 20%as compared with the one withΔx=0 mm,therefore,the mechanism can provide greaterΔx values than traditional mechanisms and sufficient stiffness,which can also be used for buffering when docking.