大型射电望远镜馈源定位3T索牵引并联机构分析与设计

ANALYSIS AND DESIGN OF 3T CABLE-DRIVEN PARALLEL MANIPULATOR FOR THE FEEDBACK'S ORIENTATION OF THE LARGE RADIO TELESCOPE

在新一代大型射电望远镜的机构设计中,由于馈源质量的大幅降低,在馈源定位的设计中,提出采用四绳索牵引并联机构,牵引馈源舱实现三个方向的平动运动,达到加大馈源工作空间的目的。为了研究非线性绳索控制机构中的尺度优化设计问题,在已知馈源舱位置的情况下,为解决由于绳索自重导致的悬链线问题,通过将悬链线简化成抛物线的方法,解决悬链线带来的高度非线性静力平衡方程组的求解问题,得到简化的静力学平衡方程。通过建立的简化静力学平衡方程,求解出四绳索牵引并联系统的工作空间与设计参数间的关系,并使用一种以力优化为目标的优化算法得到工作空间中四绳索静力平衡下的精确索拉力和伸长量。通过综合考虑满足条件的参数,最终给出满足设计要求的机构优化尺度参数。

In the large radio telescope mechanism design, due to the weight of the feedback cabin＇s decrease, a four cable-driven parallel manipulator to control the three directors＇ pure translations is proposed for expanding the workspace of the feedback cabin. For discussing the dimension design of the nonlinear cable-driven mechanism, due to the catenaries caused by cable＇s weight, a method is adopted to approximate the catenaries as parabolas at a known position to solve the nonlinear static equivalent equations of the four cable-driven parallel manipulator. The simplified static equivalent equations are given. The relation of the workspace and the preferences are explained through the simplified static equivalent equations. Meanwhile, the four cables＇ tensile forces and the elongate in the demanded workspace are given by using an optimized arithmetic. At last, the dimension parameter of the mechanism satisfying the demand is presented by comprehensive analysis.