多环耦合机构末端件的自由度研究

发布时间：2018-05-10 06:11

  本文选题：自由度 + 过约束　； 参考：《北京工业大学》2014年硕士论文

【摘要】：多环耦合机构是一类新型的复杂机构，已作为重要的组件应用于仿生机器人、航空、避难等多种领域，，但其理论研究还很缺乏。在机构学中，对一个新机构最基本的理论认识就是先知道它的自由度。但是目前而言，关于多环耦合机构的自由度方法研究很少，并且由于结构的复杂性和耦合性，导致传统的自由度方法不能正确计算此类机构的自由度。因此，探讨适合多环耦合机构的自由度方法，是一个新的研究方向，也是多环耦合机构构型设计和运动分析的基础。 本文针对多环耦合机构的自由度问题，从最关键的耦合特性和约束分析两个方面出发，提出了运动分流法、耦合机构解耦法以及机构等效分析法，形成了一种适合多环耦合机构末端件自由度分析的新方法，并通过实例分析来验证此方法的有效性和适用性。主要内容如下： 对多环耦合机构开展耦合特性分析。提出三种基础耦合模型，并根据其运动特性，提出对应的运动分流标记法及标记原则，并扩展应用于多环耦合机构，提出了耦合机构的结构解耦法，将耦合机构转化为含多个独立结构的运动链组合。 基于螺旋理论，对每一个独立运动链进行运动和约束分析。利用前述标记方法，从一级节点开始，对节点构件的运动和约束进行分析，利用“广义运动链”等效替换，迭代进行后一级节点的约束分析和等效替换，直至将每一个独立运动链结构最终等效为一个单链。至此，多环耦合机构等效为常规的并联机构。 分析等效并联机构末端件的连续自由度。计算等效并联机构的运动螺旋和约束螺旋，并利用约束的线性相关性确定机构的过约束，用修正的Grübler-Kutzbach公式计算等效并联机构末端件的自由度数，或对等效机构的约束螺旋系求二次反螺旋，就得到末端件的自由度性质，并根据连续有限位型进行自由度瞬时性判别。 应用提出的新方法分别对三类典型多环耦合机构进行了自由度分析，包括：具有独立分支局部耦合结构的混联机构、非对称耦合机构和对称耦合机构。通过Solidworks三维软件对这些机构进行实体建模和仿真模拟，以及与其它方法的对比分析，验证了此方法的有效性和适用性。 本文提出的新方法是对现有的基于螺旋理论的自由度原理的发展和创新，对多环耦合机构的进一步开发应用具有积极的促进作用。
[Abstract]:Multi-loop coupling mechanism is a new type of complex mechanism, which has been used as an important component in many fields such as bionic robot, aviation, shelter and so on, but its theoretical research is still lacking. In mechanism, the most basic theoretical understanding of a new mechanism is to know its degree of freedom. But at present, there are few researches on the degree of freedom method of multi-loop coupling mechanism, and because of the complexity and coupling of the structure, the traditional freedom of freedom method can not calculate the degree of freedom of this kind of mechanism correctly. Therefore, it is a new research direction to discuss the degree of freedom method suitable for multi-ring coupling mechanism, which is also the basis of configuration design and motion analysis of multi-ring coupling mechanism. In this paper, the motion shunt method, the decoupling method and the equivalent mechanism analysis method are proposed to solve the problem of the degree of freedom of the multi-ring coupling mechanism from the two aspects of the most critical coupling characteristics and constraint analysis, such as motion shunt method, coupling mechanism decoupling method and mechanism equivalent analysis. A new method for the analysis of the degrees of freedom of the end parts of a multi-loop coupling mechanism is proposed. The effectiveness and applicability of the method are verified by an example. The main contents are as follows: The coupling characteristics of multi-ring coupling mechanism are analyzed. In this paper, three kinds of basic coupling models are proposed, and according to their motion characteristics, the corresponding motion shunt marking method and marking principle are proposed, and extended to the multi-ring coupling mechanism, the structure decoupling method of the coupling mechanism is proposed. The coupling mechanism is transformed into a combination of motion chains with multiple independent structures. Based on the helical theory, the motion and constraint analysis of each independent kinematic chain is carried out. By using the above marking method, the motion and constraint of the node members are analyzed from the first level node, the equivalent substitution of "generalized motion chain" is used, and the constraint analysis and equivalent substitution of the post-primary node are carried out iteratively. Until each independent kinematic chain structure is finally equivalent to a single chain. So far, the multi-loop coupling mechanism is equivalent to the conventional parallel mechanism. The continuous degree of freedom of the end part of the equivalent parallel mechanism is analyzed. The kinematic spiral and constraint screw of the equivalent parallel mechanism are calculated, and the over-constraint of the mechanism is determined by the linear correlation of the constraints. The number of degrees of freedom of the end parts of the equivalent parallel mechanism is calculated by using the modified Gr 眉 bler-Kutzbach formula. The degree of freedom of the end part is obtained by solving the quadratic inverse helical system of the equivalent mechanism, and the instantaneous degree of freedom is judged according to the continuous finite position type. The new method is applied to analyze the degrees of freedom of three typical multi-loop coupling mechanisms, including: the hybrid mechanism with independent branch local coupling structure, the asymmetric coupling mechanism and the symmetric coupling mechanism. The effectiveness and applicability of this method are verified by Solidworks 3D modeling and simulation of these mechanisms, as well as comparison with other methods. The new method proposed in this paper is the development and innovation of the existing freedom of freedom principle based on the helical theory, and it has a positive effect on the further development and application of the multi-ring coupling mechanism.
【学位授予单位】：北京工业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TP242;TH112

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本文编号：1868136