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为了提高空间望远镜次镜支撑结构的动力学性能,利用主动约束阻尼层对次镜支撑结构进行了设计,主动约束阻尼层在柔性结构表面覆盖阻尼材料和压电陶瓷材料,是对柔性结构进行振动抑制的有效手段。首先建立了主动约束阻尼层的有限元模型,采用比例微分控制算法对压电陶瓷进行闭环控制,分析了阻尼材料厚度和控制增益对支撑结构阻尼特性的影响,结果表明增大阻尼层厚度或增大控制增益能够提高结构阻尼特性,但增大阻尼层厚度同时也会降低压电陶瓷的驱动性能。对空间望远镜整体结构的分析结果显示,覆盖主动约束阻尼层后支撑结构的固有频率会略微降低,但是次镜位置的频率响应明显下降,次镜的面型精度也有提高。
In order to improve the dynamic performance of the secondary mirror support structure of space telescope, the secondary mirror support structure is designed by the active constraint damping layer. The active constraint damping layer covers the damping material and the piezoelectric ceramic material on the surface of the flexible structure, Inhibition of the effective means. First, the finite element model of the active constrained damping layer is established, and the closed-loop control of the piezoelectric ceramic is carried out by the proportional-derivative control algorithm. The influence of the damping material thickness and the control gain on the damping characteristics of the supporting structure is analyzed. Large control gain can improve the structural damping characteristics, but increasing the damping layer thickness will also reduce the driving performance of piezoelectric ceramics. The analysis of the overall structure of the space telescope shows that the natural frequency of the supporting structure decreases slightly after covering the active constraining layer, but the frequency response of the secondary mirror decreases obviously and the surface mirror accuracy of the secondary mirror increases.