固面天线可展开机构设计及动力学分析

Design and dynamic analysis of deployable mechanism for solid surface antenna

为解决抛物面式固体反射面天线收拢率及主反射面形面精度较低问题,根据天线面板的运动形式,设计一种固面天线可展开机构.基于机构位置矢量方程,利用向量封闭投影法,结合D-H坐标变换矩阵建立可展机构拉格朗日动力学模型,用MATLAB编程求解机构运动过程驱动力并分析运动学参数对驱动力的影响;利用Workbench软件分析天线收拢和展开状态下基频及阵型,采用Design Exploration优化模块中响应面法分析结构参数对可展机构基频的影响和参数灵敏度;研制天线原理样机并进行展开功能试验和模态测试,对天线展开功能和结构动力学分析进行验证.结果表明:可展机构翻转比展开过程驱动力大很多,减小输入速度、调整球铰位置和减小初始夹角能降低机构翻转过程驱动力;收拢和展开状态下天线基频满足设计要求,支撑杆尺寸参数对可展机构基频影响比切换连杆大,但可增加切换连杆尺寸参数适当提高机构基频;可展机构可重复实现天线展开功能,展开状态下天线基频和阵型与分析结果接近,具备很好的结构动力学性能.

To solve the problem of low folding rate and accuracy of the main reflective surface of paraboloid solid surface antenna, according to the motion form of antenna panel, a kind of deployable mechanism of solid surface antenna is designed. The Lagrange dynamic model is established by position vector equation, vector closed projection method and D-H coordinate transformation matrix, and the driving force of the mechanism is solved. The influence of kinematic parameters on the driving force and the antenna’s fundamental frequency and formation in the closed and deployed state are analyzed, and the response surface method is used to analyze the influence of the structural parameters on the fundamental frequency and the sensitivity. The principle prototype is developed, and the deployment function and modal test are carried out. The results show that the driving force in the process of turn is much larger than that of the deployment process, and it can be reduced by reducing input speed, adjusting the position of the spherical hinge and reducing the initial angle. The fundamental frequency of the antenna meets the design requirement, the influence of the support rod size parameters on the fundamental frequency is greater than that of switching link, the size parameter of switching link can be adjusted to increase appropriately the fundamental frequency. The deployable mechanism can realize the antenna's deployment repeatedly, and the measurement results of fundamental frequency are close to the analysis results, the antenna can realize deployment function and has good dynamic performance.