ERI: System Tautochronic Pendulum Vibration Absorbers for Next-Generation Propulsion Systems and Other Machinery

该工程研究启动（ERI）奖支持研究，使独特的振动和噪声控制技术的发展，以减少旋转系统的振动，包括直升机转子和内燃机曲轴广泛用于燃油效率的传统和混合动力电动汽车动力系统，从而促进科学的进步，促进繁荣和福利，并确保国防。该研究将产生与下一代电气化机械的离心摆减振器（CPVA）设计相关的新基础知识，该机械有可能提高混合动力电动汽车和电动汽车的推进效率和驾驶员体验。CPVA由安装在转子上的转子组成，由系统旋转驱动，并且在适当调整时，可以有效地平滑操作期间引起振动的扭转喘振问题。当前CPVA和转子系统的最先进的过调谐方法将导致对于给定的吸振器质量的振动校正性能降低。该项目将通过一种新的互时调谐方法来解决这一挑战，该方法有可能实现更直接的调谐而无需考虑稳定性，从而减少实现性能目标所需的额外传动系惯性。该奖项还将支持涉及行业合作的社区外展和学生研究项目，以及电气化推进工程新课程的开发和多元化STEM劳动力的培训。本研究的目的是作出根本性的贡献，系统的tautochrone调谐方法，其中包括一个路径的吸收质量遵循的帐户的惯性耦合的吸收器的基础（转子），并导致在一个恒定的周期自由振动的系统是独立的振幅。这种调谐方法及其对减振器设计的增强作用已在重力场中得到确认，但离心场仍存在许多重要的科学问题和挑战。类似于重力场，在离心场中的互时调谐的条件将从该振荡器的一般周期函数获得，该周期函数通过将微分方程变换为标准形式，然后要求极角速度与极径向坐标无关而导出。互时调谐条件通常由一个关于吸收体路径曲率半径的非线性微分方程组成，其解就是系统的互时运动路径。离心场的一个根本区别是振子系数取决于系统的动量常数。由吸收器和转子运动组成，这种对系统动量的概括可能会彻底改变阶次调谐的概念，其中系统互时路径预计将在所有动量水平上保持调谐，而不仅仅是转子速度，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进行评估来支持审查标准。

This Engineering Research Initiation (ERI) award supports research that enables the development of unique vibration and noise control technologies to reduce vibrations in rotating systems, including helicopter rotors and crankshafts of internal combustion engines widely used in fuel-efficient conventional and hybrid electric vehicles powertrains, thereby promoting the progress of science, advancing prosperity and welfare, and securing the national defense. The research will generate new fundamental knowledge related to the design of centrifugal pendulum vibration absorbers (CPVAs) for the next-generation of electrified machinery that has the potential to improve both propulsion efficiency and driver experience for hybrid electric and electric vehicles. CPVAs consist of pendulums mounted on a rotor, driven by system rotation, and when properly tuned, can efficiently smooth problematic vibration-inducing torsional surging during operation. Current state-of-the-art overtuning approaches of a CPVA and rotor system will result in reduced vibration correction performance for a given absorber mass. This project will solve this challenge via a novel tautochronic tuning approach, which has the potential to enable more direct tuning without stability concerns, thereby reducing added driveline inertia required to achieve performance objectives. This award will also support community outreach and student research projects involving industry collaborations and the development of new curriculum in electrified propulsion engineering and training of a diverse STEM workforce. This research aims to make fundamental contributions to a system tautochrone tuning methodology, which consists of a path for the absorber mass to follow that accounts for the inertial coupling of the absorber to the base (rotor), and results in a constant period free vibration of the system that is independent of amplitude. This tuning methodology and its enhancements to vibration absorber design has been identified in a gravity field, but a number of important scientific questions and challenges remain for the centrifugal field. Similar to the gravity field, conditions for the tautochronic tuning in a centrifugal field will be obtained from a general period function for this oscillator that is derived by transforming the differential equation to a standard form, and then requiring that the polar angular speed is independent of the polar radial coordinate. The tautochronic tuning conditions will generally consist of a nonlinear differential equation for the radius of curvature of the absorber path, whose solution is the system tautochronic motion path. A fundamental difference in the centrifugal field is that the oscillator coefficients depend on the system momentum constant. Consisting of both absorber and rotor motion, this generalization to system momentum could revolutionize the concept of order-tuning, where a system tautochronic path is expected to remain tuned across all momentum levels, instead of just rotor speeds, as has been understood for many decades.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.