提出了利用一种可实现一个移动和两个转动的小型3自由度(3-DOF)并联机构来支撑并控制次镜, 以达到激光精确聚焦目的的方案。通过对小型3-PRS机构的运动模式分析, 采用欧拉角描述动平台的运动方式, 对其运动学特性做了简要分析。引入该机构连接杆的质量分布因子, 利用虚功原理建立了逆动力学模型。基于建立的动力学模型, 提出了两种控制策略方案。利用ADAMS/Control模块和MATLAB/Simulink模块联合仿真了该机构的控制精度。最后将该机构应用于实际光路系统中, 测量了两种控制方案下该机构控制的调焦次镜对聚焦光斑性能的影响。仿真结果充分证明了该机构完全满足支撑激光聚焦次镜结构的设计要求。

A 3-DOF parallel 3-PRS mechanism, which could realize one translational and two rotational motions as well as support secondary mirror used in laser beam focusing, was proposed. According to the analysis of motion mode, traditional Euler angle for describing the motion of moving platform was adopted, and based on that, kinematic model of a 3-DOF mini mechanism was built to analyze its inverse kinematics performance. The inverse dynamics modeling with principle of virtual work was derived by introducing a mass distribution factor of link legs. Based upon the established model, two control systems were implemented on the mini 3-PRS parallel manipulator. Then, control accuracy of the robot was obtained by combining ADAMS/Control with MATLAB/Simulink. Moreover, the quality of laser speckle was evaluated by applying the mini 3-PRS robots into an actual optical system. The derived results prove that a mini 3-DOF mechanism can fulfill the design requirements of the structure for supporting secondary mirror.