二自由度柔性铰链连杆机构的设计方法与综合特性研究

发布时间：2018-05-07 00:17

本文选题：柔性机构 + 柔性铰链　；参考：《中北大学》2012年硕士论文

【摘要】：柔性机构作为现代机构学的一个重要分支，已成为很多学者研究的热点。柔性机构具有无摩擦、无间隙、噪声小等诸多优点，能够满足现代机械的要求，这也使得柔性机构在微机电系统（MEMS）、航空航天、生物医学等众多高科技领域得到广泛的应用。但柔性机构的设计理论和方法不够成熟，还有待完善。目前，很多学者对柔性铰链四杆机构的设计方法、动力学特性、优化设计等方面进行了较为深入的研究，但针对二自由度柔性铰链连杆机构的研究相对较少。而二自由度柔性铰链连杆机构是研究三自由度柔性连杆机构和其它空间柔性机构的基础。本文的研究成果将为进一步研究其它更为复杂的柔性机构提供理论支持。本文选择以连杆作为结构单元的二自由度柔性铰链机构作为主要的研究对象，重点研究该机构的设计方法、动力学特性、可靠性和优化设计。首先，柔性铰链作为柔性机构的四种基本组成元素之一，是柔性机构最重要的组成部分，决定了整个柔性机构的特殊性能。因此，本文分别对三种柔性铰链的柔度、精度特性、切口附近的最大应力进行了理论分析，得出了计算公式，并将对不同结构参数代入到计算公式进行求解。对精度特性和切口附近的最大应力进行了仿真实验，，得出了精度特性和切口附近的最大应力随柔性铰链的结构参数之间的变化规律，并将切口附近的最大应力的理论分析值与仿真数据进行了对比分析，证明了理论推导的准确性。其次，本文对三种柔性连杆机构的设计方法进行了研究，首次提出了二自由度柔性铰链六杆机构。三种连杆机构的研究方法基本相同：先根据虚功原理建立柔性机构的伪刚体模型，得出设计的普遍公式；然后在伪刚体模型的基础上建立拟柔性模型；最后对二自由度柔性铰链六杆机构进行仿真实验，并将实验结果和理论计算结果进行对比。再次，对柔性连杆机构的综合特性进行了研究。进行动力学特性分析时，研究了三种机构的动力学特性，重点研究了二自由度柔性铰链五杆机构，得出了固有频率的计算方法。同时对该机构进行了仿真研究，得出了多阶振型的固有频率和幅频特性。研究可靠性时，先对基础理论进行了归纳和总结，接着对二自由度柔性铰链五杆机构进行了实例和仿真研究。仿真研究主要分析了仿真次数、载荷均值和宽度均值对可靠度的影响，并将仿真数据绘制成曲线，得出了四者之间的变化规律。最后，开展了优化设计方面的研究工作。建立以追求柔性铰链的性能最优为目标和以追求整个机构的质量最小为目标的优化设计的数学模型，并对优化设计的数学模型进行了求解。
[Abstract]:As an important branch of modern mechanism, flexible mechanism has become a hot spot of many scholars. Flexible mechanism has many advantages, such as no friction, no clearance, low noise and so on, which can meet the requirements of modern machinery. It also makes flexible mechanism widely used in many high-tech fields such as MEMS, aerospace, biomedicine and so on. However, the design theory and method of flexible mechanism are not mature enough and need to be perfected. At present, many scholars have carried on the thorough research on the design method, the dynamics characteristic, the optimization design and so on of the flexure hinge four-bar mechanism, but the research for the two-degree-of-freedom flexure hinge linkage mechanism is relatively few. The two-degree-of-freedom flexure hinge linkage mechanism is the basis for the study of three-degree-of-freedom flexible linkage mechanism and other spatial flexible mechanisms. The results of this paper will provide theoretical support for the further study of other more complex flexible mechanisms. In this paper, a two-degree-of-freedom flexure hinge mechanism with connecting rod as the structural element is chosen as the main research object, and the design method, dynamic characteristics, reliability and optimization design of the mechanism are emphatically studied. Firstly, as one of the four basic components of flexible mechanism, flexure hinge is the most important component of flexible mechanism, which determines the special performance of the whole flexible mechanism. Therefore, in this paper, the flexibility, precision characteristics and maximum stress near the notch of three kinds of flexure hinges are theoretically analyzed, and the calculation formulas are obtained, and the different structural parameters are added to the calculation formula to solve the problem. The accuracy characteristics and the maximum stress near the notch are simulated, and the variation law between the precision characteristic and the maximum stress near the notch with the structural parameters of the flexure hinge is obtained. The theoretical analysis value of the maximum stress near the notch is compared with the simulation data, and the accuracy of the theoretical derivation is proved. Secondly, the design methods of three kinds of flexible linkage mechanisms are studied in this paper, and the two degree of freedom flexure hinge six-bar mechanism is proposed for the first time. The research methods of the three linkage mechanisms are basically the same: firstly, the pseudo-rigid body model of the flexible mechanism is established according to the principle of virtual work, and the universal formula of the design is obtained, and then the quasi-flexible model is established on the basis of the pseudo-rigid body model. At last, the simulation experiment of two degree of freedom flexure hinge six-bar mechanism is carried out, and the experimental results are compared with the theoretical calculation results. Thirdly, the comprehensive characteristics of flexible linkage mechanism are studied. The dynamic characteristics of three kinds of mechanisms are studied, especially the two-degree-of-freedom flexure hinge five-bar mechanism, and the calculation method of natural frequency is obtained. At the same time, the simulation of the mechanism is carried out, and the characteristics of the natural frequency and amplitude frequency of the multi-order mode are obtained. In the study of reliability, the basic theory is summarized firstly, and then the two-degree-of-freedom flexure hinge five-bar mechanism is studied by example and simulation. The simulation research mainly analyzes the influence of the times of simulation, the average load and the average width on the reliability, and draws the curve of the simulation data, and obtains the law of variation between the four. Finally, the research work of optimization design is carried out. A mathematical model of optimal design with the aim of pursuing the optimal performance of the flexure hinge and the minimum mass of the whole mechanism is established, and the mathematical model of the optimal design is solved.
【学位授予单位】：中北大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TH112

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