反作用轮扰动特性测量及研究

Measurement and Study of Disturbance Characteristics of Reaction Wheel Assembly

反作用轮微振动是影响卫星姿态控制精度的重要因素。测量反作用轮扰动的目的是掌握其扰动规律,进而采取相应的控制方法和隔离技术。考虑到反作用轮的扰动与安装条件有关,使用"刚性六分量测试平台"和"柔性六分量测试平台"两种方法进行反作用轮扰动特性测量,并从三个方面对两种方法得到的结果进行比较。比较结果表明,不同测试条件下得到的谐波数是相同的;安装结构刚度降低会降低反作用轮的固有频率;柔性安装条件的减振作用会降低扰动峰值。试验结果可以为探讨卫星结构动态特性对扰动力的影响提供经验和指导。

Micro-disturbance of reaction wheel assembly （RWA） is a key factor affecting the accuracy of spacecraft attitude control. The purpose of measuring the RWA disturbance is to obtain its disturbance characteristics, then to adopt corresponding control methods and isolation systems to restrain them. Considering the disturbance of reaction wheel assembly is related with the fixing condition, two methods named ＇rigid six-axis test bed＇ and ＇flexible six-axis test bed＇ were adopted respectively to measure the disturbance. Measurement results of two methods were compared through three aspects. Comparison results show that the same harmonic numbers are obtained in different measuring conditions, but lower stiffness of fixing condition reduces the nature frequency of RWA. Disturbance peaks reduce as a result of the damping effect of flexible fixing condition. This experimental result may provide experience and guidance for the effect of RWA disturbance for analysis of satellite dynamic characteristic.