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卫星天线指向精度要求高,天线驱动机构中有运动副的存在就不可避免地含有间隙,研究间隙等非线性因素对卫星天线驱动机构动态特性影响尤为重要。以某型卫星天线双轴驱动机构为研究对象,基于虚拟样机技术,采用非线性弹簧阻尼模型建立了间隙处的接触碰撞模型,同时采用库伦摩擦模型考虑运动副间隙处的摩擦作用。通过对虚拟样机进行动力学仿真,分析研究了运动副间隙及其大小、不同驱动力矩等因素对双轴驱动机构动态特性的影响规律。结果表明:间隙及过大的驱动力矩将使天线定位精度降低、稳定性变差。综合考虑各因素影响,对卫星天线系统进行结构优化,是提高天线定位精度的有效途径。
Satellite antenna pointing accuracy is high, the presence of a moving pair in the antenna driving mechanism inevitably contains a gap, the study of the gap and other nonlinear factors on the dynamic characteristics of the satellite antenna driving mechanism is particularly important. Taking the biaxial drive mechanism of a certain type of satellite antenna as the research object, the contact collision model at the gap was established based on the virtual prototype technology and the nonlinear spring damping model was established. At the same time, the Coulomb friction model was used to consider the friction effect at the secondary clearance. Through the dynamic simulation of the virtual prototype, the influence law of the secondary clearance of the movement, its size and different driving torque on the dynamic characteristics of the biaxial drive mechanism is analyzed. The results show that the gap and the excessive driving torque will reduce the antenna positioning accuracy and the stability will be worse. Taking all the factors into consideration, optimizing the structure of the satellite antenna system is an effective way to improve the positioning accuracy of the antenna.