多接触约束系统的动力学仿真计算稳定性研究

发布时间：2018-05-29 13:23

本文选题：多接触约束 + 计算稳定性　；参考：《电子科技大学》2011年硕士论文

【摘要】：在对包含多接触约束的系统进行虚拟样机仿真时候,由于接触数目的繁多,系统的计算效率和求解成功率通常不高,存在明显的计算稳定性的问题,其中接触的强非线性是导致计算困难的主要原因之一。这些问题在一定程度上阻碍了虚拟样机系统在机械动力学系统中的应用和发展。在对多接触约束系统计算方法的研究和总结前人求解此类问题的方法的基础上,本文采用实时激活消隐接触约束的方法,提高了求解包含多约束接触的系统的求解效率,并且能够保证计算结果的精确性;在研究拓扑变化稳定性的理论的基础上,对系统计算过程中出现的稳定性方面的问题进行了分析和讨论,总结出保证系统拓扑稳定变化的范围。研究的内容主要包括以下几个部分: (1)在对机械动力学和接触力学理论进行学习的基础上,总结前人关于求解多接触约束系统的方法,对手动激活消隐接触约束的方法进行改进得到实时激活消隐约束的方法,在保证求解精度和正确性的前提下,提高了系统的计算效率。 (2)对系统输出的雅克比矩阵进行分析,找到了系统求解计算雅克比矩阵的相关信息,揭示了提高系统求解效率提出的实时激活消隐的方法的数学本质。 (3)以系统稳定性理论为指导,分析了多接触约束系统在计算过程中由于消隐激活约束带来系统拓扑的变化,从而导致可能出现的不稳定状况;用一个实际的包含多接触的链传动模型为例子,验证了由于改变初始条件带来的系统不稳定状况,并在这个过程中观察到了混沌现象;通过这个实验找出保证系统能够稳定求解的一个影响因子和范围。本文在总结前人的基础上采用实时激活消隐接触约束,从本质上降低了求解雅克比矩阵的维度,保证了计算精度,提高了计算的效率;研究了变拓扑机构在激活消隐过程中导致的拓扑变化对系统的稳定性的影响,并对系统由于初始条件变换可能引起的混沌现象的产生进行了分析,推动了虚拟样机技术在机械动力学中的应用。
[Abstract]:In the virtual prototype simulation of the system with multiple contact constraints, the computational efficiency and the success rate of the system are usually not high because of the large number of contacts, so there is an obvious problem of computational stability. The strong nonlinearity of contact is one of the main reasons for the difficulty of calculation. To some extent, these problems hinder the application and development of virtual prototype system in mechanical dynamics system. Based on the research on the calculation methods of multi-contact constraint systems and the previous methods to solve such problems, the method of real-time activation of hidden contact constraints is used in this paper to improve the efficiency of solving the systems with multi-constraint contact. On the basis of studying the theory of topological stability, the problems of stability in the calculation process of the system are analyzed and discussed. The range of the system topology stability is summarized. The contents of the study mainly include the following parts: 1) on the basis of studying the theory of mechanical dynamics and contact mechanics, the methods of solving multi-contact constraint system are summarized, and the method of manual activation of hidden contact constraint is improved to obtain the method of real-time activation of blanking constraint. The calculation efficiency of the system is improved under the premise of ensuring the accuracy and correctness of the solution. 2) by analyzing the Jacobian matrix output from the system, the relevant information of solving the Jacobian matrix is found, and the mathematical essence of the real-time activation blanking method proposed to improve the efficiency of the system solution is revealed. 3) under the guidance of system stability theory, this paper analyzes the potential instability of multi-contact constrained system due to the change of system topology due to the hidden activation constraint in the calculation process. Taking a practical chain transmission model with multiple contacts as an example, the instability of the system caused by changing the initial conditions is verified, and chaotic phenomena are observed in the process. Through this experiment, we find out an influence factor and range to ensure the system can be solved stably. In this paper, based on the conclusion of predecessors, real-time activation of hidden contact constraints is used to reduce the dimension of solving Jacobian matrix, ensure the accuracy of calculation and improve the efficiency of calculation. In this paper, the influence of topology change on the stability of the system caused by the active blanking of the variable topology mechanism is studied, and the chaotic phenomena caused by the change of the initial conditions of the system are analyzed. The application of virtual prototyping technology in mechanical dynamics is promoted.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TH113

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