失谐机构的振动局部化特性研究

Many mechanisms applied in spacecrafts, aerocrafts and robots possess obvious periodicity and symmetry in their configuration, such as the deployable mechanism of a spacecraft, the axisymmetric vectoring exhaust nozzle of an aeroengine, and the symmetrical parallel robot mechanism, etc. Because of many random factors in material and manufacture, there are differences between sub-mechanisms of the aforementioned mechanisms, namely mistuning. Vibration localization occurrs in mistuned mechanisms and small mistuning can lead to a remarkable change of the dynamic performance. The dynamics of the mistuned mechanism to consider the vibration localization will be studied in this project, including the researches on characteristics of vibration mode localization and dynamic response localization of mistuned mechanisms, and probabilistic characteristics of vibration mode localization and dynamic response localization of random mistuned mechanisms. The objective of this project is to reveal the vibration mode localization characteristics of the flexible mistuned mechanisms in motion, anlyze the influences of vibration localization to dynamic precision and stress, and present the methods of the probabilistic dynamic analysis and mistuning sensitivity analysis of the random mistuned mechanisms, considering on the couping of large range rigid motion and small range elastic vibration. This project have an important significance to develop the dynamics and reliability design theory of flexible mechanisms with periodicity and symmetry in their configurations.

航天、航空和机器人等领域应用的许多机构在构型上具有周期对称性质，如空间站和飞船展开机构、航空发动机轴对称矢量喷管机构、对称并联机器人机构等。由于材料和制造等方面存在诸多随机因素，使得周期机构各子机构之间必然存在一定差异，即失谐，而小量的失谐就可以导致周期机构动态特性的显著变化，即产生所谓的振动局部化现象。本项目研究失谐周期机构系统的振动局部化特性，主要研究内容为：失谐周期机构振动模态局部化特性研究；失谐周期机构动态响应局部化特性研究；随机失谐周期机构振动模态局部化特性研究；随机失谐周期机构动态响应局部化特性研究。研究目标是针对大范围刚体运动与小范围弹性振动耦合的特点，揭示柔性失谐周期机构在不同位形下的振动模态局部化特性，分析振动局部化对动态精度和动态应力的影响，建立随机失谐周期机构的动态分析方法和失谐灵敏度分析方法。研究成果对发展柔性周期机构动态设计和可靠性设计理论具有重要意义。

周期机构是一定数量的子机构通过串联或者并联形式连接在一起的机构系统。在航空、航天和机器人等高精度机械系统中得到了应用。由于各种随机因素导致各个子机构之间的差异，这种差异在通用机械中叫做随机量，而周期机构的各个子机构之间的差异叫失谐。失谐在周期机构的部分子机构中会产生动态响应的显著变化，即振动局部化现象。项目研究了谐调机构和失谐机构的失谐动态响应，随机失谐机构的动态响应可靠性，不同构型的机构失谐振动模态和振动局部化，刚体和柔体机构失谐振动动态响应局部化，并联多线程线锯机构局部化实验研究。研究成果对发展柔性周期机构动态设计和可靠性设计理论具有重要意义。