Nanometer Positioning of a Dual-Drive Gantry Table with Precise Yaw Motion Control

具精密偏轉角控制的龍門雙驅平台奈米精度定位控制

楊岡錦(Kang-Chin Yang) ； 謝成(Chen Hsieh)

《中國機械工程學刊》 36卷2期 (2015/04) Pp. 107-117

摘要

本研究針對雙驅式龍門平台發展奈米精度定位控制技術。此龍門平台同時搭載一滑台，可在垂直平台運動方向滑動及轉動。平台搭配線性光學尺，經過訊號分割後，解析度為4nm/count。控制要求除了定位誤差需為0 count外，此龍門平台的偏轉角必需保持在1弧秒之內，即使所搭載的滑台正在同時移動及轉動。不同於一般的主從式控制或交叉藕合控制，本研究根據龍門系統的動力學，將龍門平台的控制分解為位移及旋轉兩獨立控制迴路。同時為了達到奈米級的最後定位精度，系統模型加入了靜摩擦動態模型，以供最後精密微調控制。實驗結果顯示出在運動期間偏轉角小於0.6弧秒，且在穏態時小於0.01弧秒。當移動滑台靜止時，平台到位擺動量在± 1 count以內，已達此系統在氣浮軸承雜訊干擾下的定位極限。

並列摘要

This article proposes a control strategy to position the stage of a dual-drive gantry table with nanometer precision. Furthermore, the yaw angle of the stage on which a platform is mounted is confined to an order of a micro-radian, even if the platform is rotating and/or sliding at the same time. Rather than adopting the traditional master-slave or cross-couple strategy, this research decoupled the control into translational and rotational control loops according to the system dynamics. In order to overcome the friction effect and achieve nanometer precision, a simplified pre-sliding dynamic model is included in the table's dynamic model for the fine tuning phase. Experimental results show the yaw angle of the proposed gantry stage is less than 0.6 arc-second during motion and less than 0.01 arc-second at steady state. The in-position vibration is bounded within ± 4 nm when the platform is still, which is at the same level of the background noise produced by the air bearing of the platform.

並列關鍵字

dual-drive gantry system ； precision positioning ； friction ； yaw control