【作者】 罗维；

【导师】 李瑞琴；

【作者基本信息】 中北大学 ， 机械设计及理论， 2012， 硕士

【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。更多还原

【Abstract】 Compliant mechanisms as an important branch of modern mechanisms, have become theresearch focus for many scholars. Compliant mechanism have no friction, no clearance, littlenoise and many other advantages, it can meet the requirements of modern mechanical.Compliant mechanisms have been widely used in micro-electromechanical systems (MEMS),aerospace, biomedical and many other high-tech fields. Compliant mechanisms design theoryand methods are not mature enough yet to be perfected. At present, many scholars haveresearched on the design methods, dynamic, optimal design for the four-bar flexible hingemechanisms. But relatively few research on the two degrees of freedom of the flexiblehinge-bar mechanisms. Two degrees of freedom of the flexible hinge-bar mechanisms is thebasis of the three degrees of freedom of flexible hinge mechanisms and other flexible spacemechanisms. The result of this paper provides some theoretical support for the further studyon other more complex compliant mechanisms.This paper have chosen the bar linkage as a structural unit of the two degrees of freedomcompliant mechanism as the main object of study, focus on the design method, dynamics,reliability and optimal design of the two degrees of freedom of the flexible hinge-barmechanisms.Firstly, flexible hinge is one of the four basic elements of compliant mechanisms, and isthe most important part of compliant mechanisms, and determines the special behavior ofwhole compliant mechanisms. Therefore, this paper studies on flexibility, precisioncharacteristics and the maximum stress near the notch of three kinds of flexible hinge.Simulation experiment is also processed on precision characteristics and the maximum stressnear the notch, precision characteristics and the maximum stress near the notch with variation between the structural parameters of flexible hinge is gained, and theoretical analysis of valueand simulation data is compared, and it proves the accuracy of the theoretical derivation.Secondly, this paper research on design method of three kinds of flexible hinge-barmechanisms, first proposed the two degrees of freedom of the flexible hinge six-barmechanisms. The research methods used by the three kinds of flexible hinge-bar mechanismsis basically the same: firstly, pseudo-rigid body model of the compliant mechanisms is created,according to the principle of virtual work. And draw the design of the universal formula; thenthe imitate-compliant-body model is created, which is on the basis of pseudo-rigid bodymodel. Finally, simulation experiment of the two degrees of freedom flexible hinge six-barmechanisms is also processed. And the simulation result and the theoretical computationresults are contrasted.Again, this paper researches the synthetic characteristics of the flexible hinge-barmechanisms the integrated nature of the flexible bar linkage. It researches on the dynamicscharacteristics of three mechanisms. It focuses on the two degrees of freedom of the flexiblehinge five-bar mechanisms, the method of calculation of natural frequency is gained. Andsimulation research is also processed on the mechanisms, natural frequency andfrequency-amplitude characteristic under multiple vibration modeis is also gained. It firstlyresearches the conclusion and summary of basic theory when involves reliability.Then itresearches on the example and simulation of two degrees of freedom of the flexible hingefive-bar mechanisms. It researches the number of simulation, average load and average widthwhich impact on reliability, and simulation data is plotted as a curve, variation law is obtainedbetween the four.Finally, optimal design research is also processed. The mathematical model of theoptimal design, which pursuit the performance optimization and pursuit the least value ofmass, is established. The solution of mathematical models of optimal design is obtained.更多还原