A Study on Ultra-precise Positioning over A One-millimeter Stroke Using Differential Ball Screw

本研究的目的是实现一个简单的定位机制，纳米级的分辨率超过一毫米的行程使用差动滚珠丝杠。使用滑动型螺杆的差动螺杆机构已用于以精细分辨率定位。但目前还没有人尝试利用滚珠丝杠实现差动机构的超精密定位，因此其在纳米级的定位性能还没有得到讨论。丝杠轴有两部分滚珠丝杠，即A部分和B部分，它们位于同一轴线上，其公称导程分别为P_A=2.00 mm和P_B=1.95 mm，因此差动导程（d=P_A-P_B）为0.05 mm。阐明了滚珠丝杠A和B之间导程误差的相位不相同。然而，据估计， ...更多信息 通过调整两螺母之间的相位可以减小差动超前误差。为探讨滚珠丝杠副的定位性能，设计并制作了定位机构样机，并对其进给特性和定位特性进行了详细的测量。在实验的基础上，阐明了丝杠跳动误差和直线导轨摩擦力是影响差动机构性能的关键干扰因素，并针对上述干扰因素对定位机构进行了改进，构建了行程超过1 mm的超精密定位系统。设计了柔性元件，消除了丝杆跳动误差的影响。采用V型槽的滚动导轨，减少了导轨元件的摩擦。修正后的工件台行程误差完全消除了跳动误差的影响。经验证，该系统的典型行程误差为0.9 μm，波动小于0.5 μm。在微观范围内，工作台位移与转角成线性关系，比例系数与设计值一致。在上述实验结果的基础上，建立了一种定位机构的结构，以发挥差动滚珠丝杠的能力。少

This study aims at realizing a simple positioning mechanism with nanometer level resolution over a one-millimeter stroke using a differential ball screw. Differential screw mechanism using a sliding type screw has been used for positioning with fine resolution. However, there has never been any trial to realize ultra-precise positioning by differential mechanism using ball screw, so that its positioning performance in nanometer range has not been discussed.A differential ball screw with outer diameter of 12 mm was manufactured on trial. The screw shaft has two part of ball screw, part A and B, in the same axis, whose nominal leads are P_A=2.00 mm and P_B=1.95 mm, so that the differential lead (d=P_A-P_B) is 0.05 mm. The lead error of the manufactured ball screw was measured precisely, and the positioning performance of the differential ball screw was estimated. It is clarified that the phase of lead error is not identical between the ball screw A and B. However, it is estimated that th … More e differential lead error can be decreased by adjusting the phase between the two nuts. To discuss the positioning performance of the ball screw, a prototype of positioning mechanism was designed and constructed, and the feed or positioning characteristics were measured in detail. On the basis of the experimental results, it is clarified that the run out error of the screw shaft and the friction of the linear guide ways become critical disturbances for the differential performance.The positioning mechanism was revised to improve the performance avoiding the above disturbances, and an ultra-precise positioning system over a one-millimeter stroke was constructed. Flexible elements are devised to eliminate the effect of run out error of the screw shaft. Rolling guide ways using V-flat shaped groove are designed to decrease the friction of the guide way elements. After the revisal, the effect of run out error is completely eliminated from the travel error of the stage. It is confirmed that the representative travel error is 0.9 μm with the fluctuation less than 0.5 μm. Linear characteristics are obtained in microscopic range that the table displacement is proportional to the rotational angle, and the proportional coefficient agrees with the designed value. On the basis of the above experimental results, a construction of positioning mechanism is established to exhibit the ability of the differential ball screw. Less