Collaborative Research: Towards a Fundamental Understanding of a Simple, Effective and Robust Approach for Mitigating Friction in Nanopositioning Stages

纳米定位平台是用于从光谱学到微增材制造的各种纳米技术工艺中精确定位的机械设备。因此，它们的精度、速度和成本对于汽车、航空航天和国防工业中的精密工程应用至关重要，因此直接影响经济福利和国家安全。使用机械的阶段（即，滑动或滚动）轴承目前是用于越来越多的大位移纳米定位应用的唯一商业上可行的选择。然而，由于摩擦的不利影响，机械轴承台的精度差且定位速度低。该奖项支持对一种简单但有效的方法进行科学调查，通过使用柔性接头将轴承连接到平台，从而减轻机械轴承平台上的预运动摩擦的影响。通过这项调查所创造的知识将提高机械轴承阶段的定位速度和精度，而不会显着增加其成本，从而有助于纳米技术工艺的商业可行性。其更广泛的影响计划包括：（i）与Aerotech，Inc.合作，a美国-该项目包括：（i）与一家基于纳米定位平台的制造商合作，以促进知识和技术转让;（ii）在两所大学编制教育课程，并通过美国精密工程学会提供的辅导培训专业工程师;（iii）与代表性不足的少数民族中学生开展外联活动，旨在激励和培养下一代高技能制造工程师。本研究的目的是获得一个基本的了解的动力学和补偿的非线性预运动摩擦作用在伺服控制质量通过摩擦隔离器。经验研究已经证明，当伺服控制质量（例如，纳米定位平台）通过摩擦隔离器与非线性预运动摩擦相互作用（即，柔顺接头）。然而，很少有人知道的摩擦隔振器的动力学。这项研究的前提是，在某些情况下，有害的动态现象（例如，极限环）可能在预运动摩擦通过摩擦隔离器作用在伺服控制质量上时发生。这一前提将得到科学的检验，以发现产生这些问题的有害现象和情况，从而得出如何避免这些问题的见解。为了实现这一目标，摩擦、摩擦隔离器和伺服参数（例如，质量、刚度和阻尼）将使用各种工具，如多尺度方法，从非线性动力学分析中得到。这将通过对机械轴承纳米定位平台进行严格的数值和物理实验来补充，以指导，验证或完善数学表征。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的知识价值和更广泛的影响审查标准进行评估来支持。

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 precision, speed and cost are critical to precision engineering applications in the automotive, aerospace and defense industries, and therefore directly impact economic welfare and national security. Stages that use mechanical (i.e., sliding or rolling) bearings are currently the only commercially viable option for a growing number of large-displacement nanopositioning applications. However, mechanical bearing stages suffer from poor precision and low positioning speeds due to the adverse effects of friction. This award supports a scientific investigation into a simple but effective approach for mitigating the effects of pre-motion friction on mechanical bearing stages by connecting the bearing to the stage using a compliant joint. Knowledge created through this investigation will increase the positioning speed and precision of mechanical bearing stages without significantly increasing their cost, hence contributing to the commercial viability of nanotech processes. Its broader impact plan includes: (i) collaborations with Aerotech, Inc., a U.S.-based nanopositioning stage manufacturer, to facilitate knowledge and technology transfer; (ii) educational curriculum development at two universities and training of professional engineers through tutorials offered by the American Society for Precision Engineering; and (iii) outreach to underrepresented minority middle school students, aimed at inspiring and equipping the next generation of highly-skilled manufacturing engineers. The objective of this research is to gain a fundamental understanding of the dynamics and compensation of nonlinear pre-motion friction acting on a servo-controlled mass through a friction isolator. Empirical studies have demonstrated significant improvements in positioning precision and speed when a servo-controlled mass (e.g., a nanopositioning stage) interacts with nonlinear pre-motion friction through a friction isolator (i.e., a compliant joint). However, very little is known about the dynamics of the friction isolator. The premise of this research is that, under certain circumstances, harmful dynamic phenomena (e.g., limit cycles) could occur when pre-motion friction acts on a servo-controlled mass through a friction isolator. This premise will be tested scientifically, to discover the harmful phenomena and circumstances that give rise to them, leading to insights on how to avoid them. To achieve this goal, mathematical characterizations of interactions between friction, friction isolator and servo parameters (e.g., mass, stiffness and damping) will be made using various tools, like the method of multiple scales, from nonlinear dynamic analysis. This will be complemented by rigorous numerical and physical experimentation on mechanical bearing nanopositioning stages, to guide, validate or refine the mathematical characterizations.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.