Exploiting Noise for Response Control: From Simple Nonlinear Systems to Slender Structures

在许多系统中自然发生的随机波动称为噪声，在许多生物和化学系统中，噪声被用来引起系统响应的大变化。 然而，使用噪声来有益地影响工程系统的响应仅受到有限的关注。 随着工程系统的工作环境变得极端，无论是在小尺度还是大尺度上，非线性、不确定性和噪声增益的影响都变得越来越重要。 对这些通常被忽视的元素的研究和可能的利用可能会使系统设计和控制取得突破性进展，并有助于扩展工程和科学的前沿。 通过该奖项的支持，将进行基础研究，以开发一个知识库，用于使用组合确定性和噪声输入，以实现非线性系统中所需的响应变化。 一个显着的影响，预计将是我们的理解的进步，基于噪声的非线性系统的控制方案和扩展这些计划的应用领域从简单的系统到复杂的系统。 通过实验证明这些方案的可行性，预计可以构建用于使用细长旋转结构的实际应用的方案，例如钻井和采矿操作以及减材制造操作，例如铣削操作。 这项工作将迎来一个新一代的研究人员训练使用工具适合非线性系统的噪声。建立在以前的努力噪声影响的非线性振荡器的响应和调查旋转系统的旋转运动进行了在马里兰州大学，一个研究小组将追求的共同目标，了解如何机械和结构系统的响应可能会改变行使部分控制噪声。该小组将进行原始实验，以探索为Hénon映射和Duffing振荡器开发的部分控制方案对双稳态Duffing振荡器实验原型的适用性。 通知的实验结果，分析和数值研究将开始与修改Jeffcott转子系统，以构建适当的部分控制算法，这些研究结果将扩展到控制细长，旋转结构的动力学。 这些发现有望为噪声和确定性输入的组合使用打开大门，用于控制非线性机械系统，这些系统表现出逃逸动力学和旋转系统的转向响应，远离旋转运动等状态，这可能对系统有害。

Random fluctuations, which are called noise, occur naturally in many systems, and in many biological and chemical systems, noise is utilized to engender a large change in the system response. However, the use of noise to beneficially influence the response of an engineering system has received only limited attention. As the operating environments of engineering systems become extreme, both at the small scales as well as the large scales, the influence of nonlinearities, uncertainties, and noise gain increased importance. The study, and possible exploitation, of these usually ignored elements may allow for breakthrough advances in design and control of systems and help extend the frontiers of engineering and science. Through support of this award, fundamental studies will be pursued to develop a knowledge base for the use of combined deterministic and noise inputs to realize desired response changes in nonlinear systems. A salient impact is expected to be the advancement of our understanding of noise based schemes for control of nonlinear systems and extension of the application realm of these schemes from simple systems to complex systems. By experimentally demonstrating the feasibility of these schemes, it is expected that one can construct schemes for practical applications where slender, rotating structures are used, such as drilling and mining operations and subtractive manufacturing operations such as milling operations. This work will usher in a new generation of researchers trained to use tools suited for nonlinear systems with noise.Building on prior efforts on noise-influenced responses of nonlinear oscillators and investigations into whirling motions of rotary systems carried out at the University of Maryland, a research team will pursue the common goal of understanding how mechanical and structural system responses may be altered by exercising partial control with noise. The group will conduct original experiments to explore the applicability of partial control schemes developed for Hénon maps and Duffing oscillators to an experimental prototype of a bi-stable Duffing oscillator. Informed by the experimental findings, analytical and numerical studies will be initiated with modified Jeffcott rotor systems to construct appropriate partial control algorithms and these findings will be extended to control the dynamics of slender, rotating structures. The findings are expected to open the doors to the combined use of noise and deterministic inputs for control of nonlinear mechanical systems that exhibit escape dynamics and steer responses of rotary systems away from states such as whirling motions, which can be detrimental to a system.