Vibration Assisted Nanopositioning: An Enabler of Low-cost, High-throughput Nanotech Processes

纳米技术是技术发展中最有前途的领域之一，也是最有可能在21世纪为美国带来巨大经济和社会效益的领域之一。纳米定位阶段是用于精确定位的机械装置，用于广泛的纳米技术工艺，从光谱学到微增材制造。因此，它们的定位速度和成本对许多纳米技术工艺的产量和规模至关重要。目前，在超高真空环境下进行的越来越多的大位移纳米定位应用中，使用滚子轴承的级段是唯一可行的商业选择。然而，由于所谓的预滚动摩擦的不利影响，滚子轴承阶段遭受非常低的定位速度。该奖项支持一项科学研究，该研究旨在通过对滚动轴承纳米定位阶段施加高频振动来减轻滚动前摩擦对滚动轴承纳米定位阶段的影响。本研究的结果将在不显著增加成本的情况下提高滚子轴承纳米定位阶段的定位速度，从而使各种纳米技术工艺的规模扩大和吞吐量增加。本研究的重点是振动辅助纳米定位：一种将高频振动与主动振动控制相结合，应用于纳米定位阶段的新方法。本研究的目的是了解高频振动、滚动前摩擦、控制器动力学和定位速度之间的相互作用。在没有主动振动控制的理想条件下，采用运动直接分配的方法确定振动参数（振动频率和振幅）对滚动前摩擦和舞台位置控制的影响。然后将进行摄动分析（例如，使用poincar<s:1> lindstedt方法），以了解主动振动控制与高频振动相结合对舞台振动的影响。将研究的控制技术包括滑模控制和谐波抵消控制。在所有的分析中，预滚动摩擦将以越来越复杂的水平建模，从简单的达尔模型开始，建立到广义麦克斯韦滑动模型，以便逐步深入了解每个模型及其参数对分析结果的影响。采用简单的滚子轴承纳米定位台，在不同的高频振动频率/幅值、摩擦条件和控制技术下进行点对点定位实验，验证理论分析。

Nanotechnology is one of the most promising areas of technological development, and among the most likely to deliver substantial economic and societal benefits to the U.S. in the 21st century. Nanopositioning stages are mechanical devices used for precise positioning in a wide range of nanotech processes, ranging from spectroscopy to micro additive manufacturing. Hence their positioning speed and cost are critical to the throughput and scale up of many nanotech processes. Stages that use roller bearings are currently the only commercially viable option for a growing number of large-displacement nanopositioning applications performed in ultrahigh vacuum environments. However, roller bearing stages suffer from very low positioning speeds due to the adverse effects of so-called pre-rolling friction. This award supports a scientific investigation into a novel approach for mitigating the effects of pre-rolling friction on roller bearing nanopositioning stages by applying high frequency vibration to the stage. Results from this research will increase the positioning speed of roller bearing nanopositioning stages without significantly increasing their costs, hence enabling the scale up and increased throughput of a wide range of nanotech processes. This research is focused on vibration-assisted nanopositioning: a novel approach for applying high frequency vibration, combined with active vibration control, to nanopositioning stages. The objective of this research is to understand the interactions between high frequency vibration, pre-rolling friction, controller dynamics, and positioning speed. The method of direct partition of motion will be used to determine the influence of vibration parameters (vibration frequency and amplitude) on pre-rolling friction and stage position control, under ideal conditions where there is no active vibration control. Perturbation analyses (e.g., using the Poincaré-Lindstedt method) will then be carried out to understand the effects of active vibration control combined with high frequency vibration on the vibration of the stage. Control techniques that will be investigated include sliding mode control and harmonic cancellation control. In all analyses, pre-rolling friction will be modeled with increasing levels of complexity, starting from the simple Dahl model and building up to the Generalized Maxwell Slip model, in order to gain progressive insights into the effects of each model and its parameters on the results of the analyses. A simple roller bearing nanopositioning stage will be used to conduct point-to-point positioning experiments, with various high frequency vibration frequencies/amplitudes, friction conditions, and control techniques, to validate the theoretical analyses.