设计了一种基于Stewart构型的隔振系统用于空间光学载荷的在轨隔振并研究了Stewart构型的特点。首先, 使用牛顿-欧拉公式建立了隔振系统的理论模型, 根据该模型计算得到了隔振系统刚度、阻尼矩阵及各阶固有频率与主模态的数学解析式。然后, 以缩小隔振系统前六阶固有频率的分布范围为目标, 利用寻优方法优化了隔振系统的几何结构参数, 得到了用于六维被动隔振的最佳构型。最后, 分别使用有限元单元法及解析方法对隔振系统进行了模态分析, 得到隔振系统前六阶固有频率, 其理论分析值与有限单元法计算结果的最大误差为1.51%。为了论证所设计的隔振系统的有效性, 对隔振系统及光学载荷的耦合模型进行了复频响应分析, 得到3个平动及3个转动方向的复频响应曲线, 结果表明隔振系统能够将各个方向上高于10 Hz的振动衰减90%以上, 满足隔振要求。

A novel vibration isolation system based on Stewart platform was designed to attenuate the vibration of space optical payloads, and the general configuration characteristics of the Stewart platform were analyzed. Firstly, the theoretical model of the vibration isolation system was developed through Newton-Euler dynamic approach.On the basis of the model, the closed form formulation was derived to calculate the stiffness matrix, damping matrix, natural frequencies and principal mode shapes of the vibration isolation system. According to the research above, an optimization method was used to optimize the structure parameters and to narrow the distribution range of the first six natural frequencies of the isolation system, then to obtain an optimal configuration of this vibration isolation system. Finally, the finite element method and the analytic method were utilized to analyze the modes of this vibration isolation system and to obtain the first six natural frequencies of the system. The analysis indicates that the maximum error is 1.51% between the two methods. In order to demonstrate the isolation effect of the vibration isolation system, the complex frequency response was analyzed, and the translation frequency response curves and the rotation frequency response curves were obtained. It is shown that the vibration attenuation rate is more than 90% when the vibration frequency is higher than 10 Hz,which verifies that the vibration isolation system meets all the isolation requirements.