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。纳米定位平台是一种机械装置，用于在从光谱到微添加剂制造等广泛的纳米技术过程中进行精确定位。因此，它们的定位速度和成本对许多纳米技术工艺的生产能力和规模至关重要。对于在超高真空环境中执行的越来越多的大位移纳米定位应用，使用滚子轴承的工作台目前是唯一在商业上可行的选择。然而，由于所谓的预滚动摩擦的不利影响，滚子轴承工作台的定位速度非常低。该奖项支持对一种新方法的科学研究，该方法通过在滚子轴承纳米定位工作台上应用高频振动来减轻滚子轴承纳米定位工作台上预滚动摩擦的影响。这项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工作台的定位速度，从而使各种纳米技术工艺的规模扩大和产量增加。本文的研究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的新方法应用于纳米定位阶段。这项研究的目的是了解高频振动、预轧摩擦、控制器动力学和定位速度之间的相互作用。在无主动振动控制的理想条件下，采用直接运动分割法确定振动参数(振动频率和振幅)对预滚摩擦和台位控制的影响。然后将进行摄动分析(例如，使用Poincaré-Lindstedt方法)，以了解主动振动控制与高频振动相结合对工作台振动的影响。将研究的控制技术包括滑模控制和谐波消除控制。在所有分析中，滚动前摩擦的建模将随着复杂程度的增加而增加，从简单的Dahl模型到广义Maxwell滑移模型，以便逐步深入了解每个模型及其参数对分析结果的影响。利用简单的滚子轴承纳米定位工作台进行点对点定位实验，在不同的高频振动频率/振幅、摩擦条件和控制技术下，对理论分析进行验证。

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.