Nonlinear Dynamics of Pneumatic Isolators in Ultra-Precision Manufacturing Machines

超精密制造(UPM)机器能够生产对电子、生物医学、通信和其他尖端行业的进步至关重要的微米和纳米器件。作为满足UPM机器严格精度要求的关键一步，它们必须与快速移动的机器和地面运动引起的不必要的振动隔离。为此，气动(被动)隔振器通常比主动系统更受欢迎，因为它们的成本和能效相对较低。最近的研究表明，使用更复杂的控制方法可以显著提高气动隔振器的性能。然而，过去的那些研究并没有考虑到气动隔振器中众所周知的固有的复杂性和非线性行为。该奖项的目的是支持基础研究，以了解被动隔离UPM机器的非线性动力学，并确定如何利用非线性动力学的好处来改善气动隔振器的性能。所获得的知识将使美国制造业能够制造更便宜、更好、更快的UPM机器，促进国家繁荣，并影响确保国防安全的努力。在更广泛的背景下，这些发现也可以应用于更广泛类别的非线性机械和机电系统。这项研究工作还将有助于拓宽代表不足的少数群体(URM)在工程领域的代表性和保留。该研究项目将首次对气动隔振器进行非线性振动分析，以科学地揭示线性系统中观察到的模式耦合的好处是否可以扩展到非线性系统。为此，将通过实验测量和理论建模的直接协调进行非线性系统辨识，以检测和量化气动隔振器的非线性刚度和非线性阻尼。然后进行深入的理论分析，以了解气动隔离UPM电机中非线性模式耦合、稳定性和分叉之间的相互作用。利用最优控制理论确定最优设计参数，为改进气动隔振器的设计提供指导。将进行严格的物理实验来指导和验证理论发现。研究结果将为如何利用非线性动力学现象来改善气动隔振器的性能提供新的见解。PI将通过与全国黑人工程师协会和其他STEM相关活动的联系，继续关注代表不足的群体的参与。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Ultra-precision manufacturing (UPM) machines enable the production of micro- and nano-devices that are critical for the advances in the electronics, biomedical, communications and other cutting-edge industries. As a critical step in meeting UPM machine’s stringent precision requirement, they must be isolated from unwanted vibrations stemming from fast moving machines and ground motions. For this purpose, pneumatic (passive) isolators are often preferred over active systems because of their relatively low cost and energy efficiency. Recent studies have demonstrated that the performance of pneumatic isolators can be significantly improved using more sophisticated control approaches. However, those past studies did not account for the well-known inherent complex, and nonlinear, behaviors in pneumatic isolators. The aim of this award is to support fundamental research to understand the nonlinear dynamics of passively-isolated UPM machines and determine how the benefits of nonlinear dynamics can be exploited to improve the performance of pneumatic isolators. The knowledge gained will enable U.S. manufacturing industry to build cheaper, better, and faster UPM machines, advancing national prosperity and impacting efforts to secure the national defense. In a broader context, the findings can also be applied to a broader class of nonlinear mechanical and electromechanical systems. The research work will also help broaden the representation and retention of underrepresented minority (URM) in engineering fields.The research project will be the first to conduct a nonlinear vibration analysis of pneumatic isolators to scientifically reveal whether the benefits of mode coupling observed in linear systems can be extended to nonlinear systems. To this end, a nonlinear system identification via a direct reconciliation of experimental measurements and theoretical modeling will be conducted to detect and quantify the nonlinear stiffness and nonlinear damping of pneumatic isolators. A thorough theoretical analysis will then be carried out to understand the interplay between nonlinear mode coupling, stability, and bifurcation in pneumatic isolated UPM machines. Optimal control theory will be used to determine the optimum design parameters, which will then serve as guidelines for improving the design of pneumatic isolators. Rigorous physical experimentation will be performed to guide and validate the theoretical findings. The outcome of the researched work will lead to new insights on how to exploit nonlinear dynamic phenomena for improving the performance of pneumatic isolators. The PI will continue to focus on the participation from underrepresented groups though connections to the National Society of Black Engineers and other STEM-related activities.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.