弧面凸轮机构运动曲线的反求优化研究

发布时间：2018-10-17 22:31

【摘要】：空间弧面分度凸轮机构因具有结构紧凑、性能可靠等诸多优点，在自动化机械，如自动换刀系统、包装机械、自动生产线、自动交换系统等方面得到了广泛应用。以弧面凸轮为核心部件，目前已开发出了多种常用的驱动和控制装置。弧面凸轮分度机构是实现高速、高精度间歇分度运动的新型传动装置，应用广泛，受到越来越多的国内外学者的研究，并取得了显著的成果。目前其理论研究已趋于成熟。然而由于弧面分度凸轮的廓面为空间不可展开的螺旋面，这给弧面凸轮的设计、制造带来了诸多不便。在遇到弧面凸轮损坏，无法得知原有弧面凸轮的设计参数时，只能通过测量有限的数据去反求原有弧面凸轮轮廓。在原有参数化设计方法上，弧面凸轮廓面是由从动件的运动规律决定的，如果能够得到从动件的运动规律曲线，那么就能够反求出弧面凸轮的轮廓曲线。所以求解弧面凸轮廓面（线）的问题可以转化为求得符合要求的从动件运动规律曲线。为此，本文将重点放在弧面凸轮特征曲线反求优化上面，通过探索将遗传算法应用于弧面凸轮特征曲线优化反求，得出了将遗传算法用于弧面凸轮特征曲线优化设计可行，并能取得较为理想的结果。本文的工作可总结如下：（1）介绍了弧面凸轮的结构以及相关理论。列举了常用凸轮的运动规律曲线，着重介绍了通用简谐梯形运动规律。并对弧面凸轮运动规律曲线的选用原则进行了说明。从传统设计方法出发，采用坐标变换法推导出弧面凸轮工作廓面及理论廓面方程。（2）阐述了曲线的插值与拟合概念，应用几种常用的曲线插值及曲线拟合方法对弧面凸轮特征曲线进行反求，由实例结果分析了其各自的特征及优劣。（3）将遗传算法用于弧面凸轮特征曲线反求优化。介绍了遗传算法的特点及操作流程，利用罚函数对约束条件进行处理，通过具体实例验证了以实数编码的遗传算法用于弧面凸轮特征曲线优化的可行性；对不同优化目标下得到的方案进行了对比和评价，指出使用遗传算法用于此可行，并具有其独特的优点。论文主要工作是在Matlab中展开的，通过编制M文件，比较了不同曲线拟合及差值方法，最后给出了遗传算法思想下弧面凸轮特征曲线优化的解决方案，指出其应用的可行性及优势，，是一次很好的尝试，也为后续的研究奠定了一定的基础。
[Abstract]:Because of its compact structure and reliable performance, the spatial globoidal indexing cam mechanism has been widely used in automatic machinery, such as automatic tool changing system, packaging machine, automatic production line, automatic switching system, and so on. With the globoidal cam as the core component, a variety of commonly used drive and control devices have been developed. Globoidal cam indexing mechanism is a new type of transmission device which can realize high speed and high precision intermittent indexing movement. It is widely used and has been studied by more and more scholars at home and abroad. At present, its theoretical research has tended to mature. However, the profile of the globoidal indexing cam is a helical surface which can not be expanded in space, which brings many inconvenience to the design and manufacture of the globoidal cam. When the design parameters of the original globoidal cam can not be known when the globoidal cam is damaged, the contour of the original globoidal cam can only be obtained by measuring the limited data. In the original parameterized design method, the contour of the globoidal cam is determined by the motion law of the follower. If the curve of the motion law of the follower can be obtained, then the contour curve of the globoidal cam can be obtained. Therefore, the problem of solving the curve of curved cam profile can be transformed into the curve of the motion law of the follower that meets the requirements. Therefore, this paper focuses on the reverse optimization of the characteristic curve of the globoidal cam. By exploring the application of genetic algorithm to the optimization of the characteristic curve of the globoidal cam, it is concluded that it is feasible to apply the genetic algorithm to the optimization design of the characteristic curve of the globoidal cam. And can obtain more ideal result. The work of this paper can be summarized as follows: (1) the structure and related theory of globoidal cam are introduced. The kinematic curve of common cam is listed, and the general harmonic trapezoid motion law is introduced emphatically. The selection principle of the curve of globoidal cam motion law is explained. Starting from the traditional design method, the working profile and theoretical profile equations of globoidal cam are derived by using coordinate transformation method. (2) the concept of interpolation and fitting of curve is expounded. Several common curve interpolation and curve fitting methods are used to reverse the characteristic curve of globoidal cam. Their respective characteristics and advantages and disadvantages are analyzed by examples. (3) genetic algorithm is applied to reverse optimization of characteristic curve of globoidal cam. The characteristics and operation flow of genetic algorithm are introduced, and the constraint condition is treated by penalty function. The feasibility of using real coding genetic algorithm to optimize the characteristic curve of globoidal cam is verified by practical examples. The comparison and evaluation of the schemes obtained under different optimization objectives show that the use of genetic algorithm is feasible and has its unique advantages. The main work of this paper is carried out in Matlab. By compiling M file, the different curve fitting and difference method are compared. Finally, the solution of optimization of characteristic curve of globoidal cam under the idea of genetic algorithm is given. It is a good attempt to point out the feasibility and advantage of its application, and it also lays a certain foundation for further research.
【学位授予单位】：陕西科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TH112.2

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