PECASE: Analysis and Design of Discontinuity-Driven Bifurcations

机构：弗吉尼亚理工学院和州立大学该奖项侧重于非光滑动力系统的分析和设计，其特征是系统特性的突然和不连续变化，通常在机械，生物和电子模型中遇到。特别重要的是，在与环境弱相互作用开始时，这种系统的特性和运动稳定性可能发生的巨大变化，这里称为不连续驱动的分岔。例如，在人类步态的情况下，摆动脚过早地低速接触地面可能导致持续步态的稳定性丧失和随后的跌倒，特别是在肌肉疾病患者或老年人中。该项目的目标是为周期性和瞬态运动的非连续性驱动分支开发一种全面的预测方法，并制定设计标准，以减少或消除机械子系统与其周围环境之间无意碰撞的有害影响——特别是，预防因步态中过早接触地面而导致的跌倒相关伤害。这项研究工作将与开发一门初级封闭式设计课程的努力密切结合，该课程强调机电系统的性能验证测试以及在光滑和不连续驱动的分岔存在时系统响应的评估。该项目最初是作为职业奖资助的，并于2004年9月转换为工程师和科学家的总统早期职业奖（PECASE）奖。

Proposal Title: PECASE: Analysis and Design of Discontinuity-Driven BifurcationsInstitution: Virginia Polytechnic Institute and State UniversityThis award focuses on the analysis and design of nonsmooth dynamical systems, characterized by abrupt and discontinuous changes in the systems' properties, and commonly encountered in mechanical, biological, and electronic models. Of particular significance are the potentially dramatic changes in character and stability of motions of such systems that occur at the onset of weak interactions with the environment, here referred to as discontinuity-driven bifurcations. For example, in the case of human gait, premature, low-velocity ground contact of the swing foot may result in loss of stability of the sustained gait and subsequent fall, particularly in individuals with muscular disorders or the elderly. The objectives of this project are to develop a comprehensive predictive methodology for discontinuity-driven bifurcations of recurrent and transient motions and to formulate design criteria for reducing or eliminating the detrimental effects of unintentional collisions between a mechanical subsystem and its surrounding environment -- in particular, the prevention of fall-related injury due to premature ground contact during gait. The research work will closely integrate with an effort to develop a closed-ended-design course at the junior level emphasizing performance verification tests for mechatronic systems and the evaluation of a system's response in the presence of smooth and discontinuity-driven bifurcations.This project was originally funded as a CAREER award, and was converted to a Presidential Early Career Award for Engineers and Scientists (PECASE) award in September 2004.