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.%With the high demand for pointing accuracy of the satellite antenna, the joint clearance is inevitable due to the existence of the kinematic pair in the two-axis-position mechanism. So it is particularly important to study the influence of the joint clearance to satellite antenna mechanism. The two-axis-position mechanism was taken as research object, the contact dynamics model of the clearance joint was established by applying the nonlinear spring-damp model, and the friction effect was considered by applying the Coulomb friction model. The law that the dynamic characteristic of two-axis-position mechanism affected by the factors was analyzed by the dynamic simulation of the virtual prototype, such as the size of the joint clearance and the driving torque in the clearance. The results show that large joint clearance and driving torque will reduce the positioning accuracy and make the system unstable. It is a good way to increase the positioning accuracy through optimizing the structure of the satellite antenna mechanism.
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