空间望远镜次镜六自由度调整机构精密控制

Six degree of freedom precision control for space camera secondary mirror adjusting mechanism

为满足空间望远镜在轨主动光学控制需求,需要精密调整次镜相对于主镜的六自由度位姿,为此,针对6-PSS Stewart平台构型的次镜精密调整机构,设计完成了基于并联机器人关节空间方法的运动控制系统。以DSP和FPGA为核心处理器,编码器为反馈元件,集成电机三相桥为驱动元件,设计完成了次镜六自由度调整机构的运动控制电路。基于次镜调整机构的顶层逆运动学模型和底层连杆控制系统,设计完成了次镜六自由度调整机构的运动控制算法,该方法参数易于调整,利于工程实现,满足空间运动机构高可靠性调整需求。试验结果表明,该运动控制系统能够满足全行程内0.7μm(位移)和3"(角度)运动调整精度需求,能够满足空间望远镜主动光学调整任务。

For the space camera on orbit active optics requirement, the position and orientation of secondary mirror relative to the primary mirror need to be adjusted. Based on the parallel robot joint space method, the motion control system of 6-PSS Stewart platform secondary mirror adjusting mechanism was designed. By use of DSP and FPGA as the core processor, linear encoder as the feedback element and the integrated three-phase bridge as driving element, the motion control circuit was completed. Based on the top level inverse kinematics model and the bottom level link control system, the motion control algorithm of the secondary six DOF adjusting mechanism was accomplished, the control parameters were easy to be adjusted and the algorithm was easy to be used in the engineering, the requirement of high reliability adjustment for space motion mechanism was satisfied. Experimental results indicate that the 0.7 μm and 3＂ motion accuracy can be achieved, the demand of space camera active optics can be satisfied.