偏馈式构架反射器的预滑动摩擦动态模型分析

Pre-sliding friction dynamical modeling of offset-fed truss reflector

针对偏馈式构架反射器指向机构的摩擦效应提出了预滑动摩擦动态模型分析方法,为预测反射器结构响应状态提供了理论依据。首先,采用低频正弦扫频方法进行发射器结构的模态测试,结果表明在指向机构解锁状态和锁紧状态时,反射器结构基频的固有频率随激励幅值的增大而降低,非线性特征显著;其次,通过摩擦模型分析,本文首次提出反射器指向机构存在预摩擦状态,并给出了预摩擦状态的模型表达式,建立了反射器结构的非线性动力学模型;最后,对反射器结构预滑动摩擦动力学特性进行了模拟和对比验证,结果表明模拟分析得到的反射器结构基频变化规律与实测结果一致。

In view of the friction effect of the pointing mechanism of the offset-fed truss reflector, this paper presents an analysis method based on pre-sliding friction dynamic model, which provides a theoretical basis to predict the responses of the reflector structure. Firstly, low frequency sine sweep method is used to accomplish the modal testing of the truss reflector. The results show that both in the unlocked state and locking state of the pointing mechanism, the fundamental natural frequency of the reflector structure decreases with the increment of excitation amplitude, exhibiting significant nonlinear characteristics. Secondly, through analysis of the friction model, it is proposed for the first time that the reflector pointing mechanism is pre-sliding friction state. The model expressions of the pre-sliding friction are given and the nonlinear dynamic model of the reflector structure is established. Finally, the simulation and verification of the pre-sliding friction dynamic characteristics of the reflector structure are carried out, and the simulation analysis of the change regularity of the reflector structure fundamental frequencies is consistent with the results obtained by measurement.