中文摘要：

提出了一种新型多自由度可展机构9RR-12URU,可作为大口径构架式可展天线支撑机构的最小组合单元.该 机构包含3个3RR-3URU四面体可展单元,基于螺旋理论分析了单个四面体可展单元的自由度,进而采用拆分杆组法得到了 9RR-12URU组合单元机构的自由度.基于节点的空间几何位置和坐标变换矩阵推导了可展组合单元机构在收拢/展开过程中 各节点位置和速度的解析表达式,并采用RPY角描述了各节点相对于定节点的姿态变化.基于Adams软件对9RR-12URU组 合单元机构的自由度和运动学理论分析进行了仿真验证,结果表明该机构具有收拢和调姿两种自由度,使机构达到最大折 叠比.该新型多自由度可展组合单元机构结构简单、折叠比大,可用于曲面构架式可展开反射器中.

英文摘要：

A novel deployable mechanism9RR-12URU with multiple degrees of freedom （DoFs） is proposed. which can be used as the minimum composite element of the supporting mechanism of large-diameter truss antennas. This deployable mechanism consists of three 3RR-3URU tetrahedral units. The DoF of a tetrahedral unit is analyzed based on the screw theory, and then the DoF of the 9RR-12URU mechanism is obtained by using the method of splitting rod groups. According to the geometric positions and coordinate transformation matrices of the nodes, the analytic expressions of the position and velocity of each node in the folding/dq5loying process of the mechanism are derived. Furthermore, the RPY angle is adopted to describe the orientation of each node with respect to the fixed node. The theoretical analyses on the DoF and kinematics of the9RR-12URU mechanism are verified by Adams software. The results show that the mechanism has two kinds of DoFs： translational and ro tational D oF s , which contribute to achieving the maximum folding ratio of the mechanism. The9RR-12URU deployable mechanism has a simple structure and a large folding ratio,that can be applied to truss deployable reflectors with a bent surface.