应用于空间大型光机结构中的黏滞液体阻尼器

Viscous damper for use in large optomechanical structures

针对大型光机结构的结构特性,为抑制宽频噪声对结构指向稳定度及精度的影响,设计了一种可以在全频段提供高阻尼低轴向刚度的液体阻尼器。首先,对液体阻尼器的参数设计理论进行了分析;其次,通过微振动一体化集成仿真分析了引入液体阻尼器对整机的影响,由分析结果可知,在内外框架之间安装阻尼器,可以达到抑制宽频噪声的目的,一般情况下光轴指向精度(Line of Sight)可以改善50%以上,同时对结构特性改变较小;最后,设计了测试系统,对阻尼器参数的特性进行了实验研究,可知该液体阻尼器的阻尼系数随频率升高降低,在低频时可以达到18 574 N·s/m, 300 Hz时阻尼系数在300 N·s/m以上,轴向刚度约为28 659 N/m,随频率变化基本保持不变。结果表明:试验测试结果与仿真结果相符,液体阻尼器的刚度及阻尼参数的设计都达到了技术要求,根据仿真与试验的分析验证了阻尼器对大型光机结构振动抑制的有效性。

Considering large optomechanical structures,a fluid damper was designed with high damping and low axial stiffness in the full frequency range to reduce the width of frequency noise.Firstly,the theory of parameter design for a liquid damper was reviewed.Secondly,the characteristics of the fluid damper were verified using the finite element method,in addition to its influence on the entire structure.The simulation results indicated that the use of a liquid damper could effectively increase the structural damping of a spacecraft without affecting its mechanical characteristics.Moreover,it was shown that the line of sight of an optomechanical structure can be improved by more than 50%generally.The test system used to study the characteristics of the design parameters of the dampers was designed as part of this investigation.It was determined that the damping of the liquid damper decreased with an increase in frequency.A coefficient of more than 300 N·s/m was obtained at 300 Hz,while the change of the stiffness with frequency remained approximately the same.These results indicate that the experimental data are consistent with the simulation results,and the design of the stiffness and damping properties of liquid dampers satisfied the requirements.In summary,the effectiveness of liquid dampers on vibration suppression of large optomechanical structures was verified based on simulation and test results.