高精度大口径光栅拼接装置的控制算法

Design method of controlling device for tiling high pecision and large aperture grating

采用宏/微结合双驱动的少自由度并联进给结构,给出了一种光栅拼接装置设计算法。宏动部分是5PTS-1PPS型并联机构,采用步进电机驱动滚珠丝杠形式的进给机构;微动部分是5TSP-1PPS型并联机构,采用压电陶瓷驱动柔性铰链形式的进给机构;二者串联构成光栅拼接机构。计算了宏动部分和微动部分的并联机构自由度,利用并联机构运动学的逆解推导出该装置的控制算法,并根据控制算法进行了宏动、微动机构点位控制的运动学仿真。为了提高机构的定位精度,分析了机构的系统误差并提出了误差修正方法。最后,将以上算法应用到光栅拼接装置中。实验结果表明:宏动部分最大移动定位误差为3.6μm,最大转动定位误差为4.4μrad;微动部分最大移动定位误差为0.06μm,最大转动定位误差为1.2μrad;基本满足光栅拼接系统的精度要求。

A mechanical grating tiling device is designed by a macro-micro dual-drive nism with a few Degrees of Freedom（DOF）. The raster matching device is composed P of arallel mecha a macro-moving part using a step-motor controlled ballscrew unit（a 5PTS-1PPS parallel mechanism）and a micromoving part using a piezoelectric ceramics controlled flexure hinge（a 5TSP-1PPS parallel mechanism） in series. The DOFs for the macro-moving part and the micro-moving part have been calculated and the control algorithms are deduced through inversing dynamics of parallel mechanism. Then, the point-point controls of the macro-moving part and the micro-moving part are simulated subsequently In order to improve positioning precision of this mechanism, system errors have been analyzed and modified. Finally, above control algorithms are applied to the grating tiling device and experimental results indicate that the maximum linear location error is 3.6 ptm and the maximum rotation error is 4.4urad for the macro-moving part; the 0.06um and 1.2urad for the micro-moving part,obtained data can meet the precision requirement of grating tiling system.