模拟退火遗传算法在自由曲面数控加工中的实验

在自由曲面的加工中,一直面临着加工时间长的问题,本研究以提高加工效率为目的,通过分析待加工自由曲面的面曲率、残余高度等参数,计算出合理的加工步长和行距,并以此为依据将待加工曲面离散成点云即为刀触点。将刀具路径规划问题转化为求解TSP问题的最优解,为避免遗传算法早熟陷入局部最优解,引入了模拟退火算法进行改进,使用改进后的混合算法进行刀具路径寻优。对优化方法进行了仿真加工、实验加工及测量,结果表明优化方法相比传统方法刀路长度最多减少303.4mm,相对缩短了12.3%,加工效率提升较为明显,并且加工表面也取得了较好的加工效果。     

遗传算法在求解函数优化问题中的应用研究

介绍了遗传算法是一种借鉴生物界自然选择和优化机制发展起来的高度并行、随机、自适应搜索算法,阐述了在遗传算法的诸多应用中,函数优化是最显而易见的应用,分析了遗传算法的运行机理,并在Matlab环境中实现了用遗传算法求解函数优化的问题.     

求点到空间参数曲线最小距离的几种算法

建立了点到空间参数曲线最小距离的数学模型,提出了计算点到空间参数曲线最小距离的三种算法,即基于几何特征的快速迭代法、基于最优化方法的黄金分割法与二次迭代法的组合法以及格点法,分析比较了这三种算法的特点和适用范围,编制了相应的计算机程序,实现了求点到复杂曲线的最小距离,并对三种算法的计算精度和运行时间作了比较。大量算例验证了算法的有效性,其计算精确度高,非常适用于曲面、曲线的匹配计算和三坐标测量机的点相关数据处理,在工程上具有一定的实用价值。     

基于Mathematica的异面曲线最短距离的优化计算

这里基于极值原理，建立了空间异面曲线最短距离分析数学模型，给出异面曲线公垂线确定的优化原理，直接应用数学工具软件Mathematica处理实际问题，这种新方法为求解实际工程问题提供良好的思想。     

基于CBR和遗传算法的模具智能CAD系统

在分析和总结当前智能设计方法的基础上，采用CBR与遗传算法这两种智能技术，用C Builder和SQL Server开发了一个模具智能CAD系统，集成人机智能进行模具结构方案优化设计。     

Precision modeling of form errors for cylindricity evaluation using genetic algorithms

A heuristic approach is proposed in this paper to model form errors for cylindricity evaluation using genetic algorithms (GAs). The proposed GAs method shows good flexibility and excellent performance in evaluating the engineering surfaces via measurement data involved with randomness and uncertainty. The numerical-oriented genetic operator is used as a basic representation for error modeling in the paper. The theoretical basis for the proposed Gas-based cylindricity evaluation algorithms is first presented. The performance of the method under various combinations of parameters and the precision improvement on the evaluation of cylindricity are carefully analyzed. One numerical example is presented to illustrate the effectiveness of the proposed method and to compare the Gas-based modeling results with those obtained by the least-squares method. Numerical results indicate that the proposed GAs method does provide better accuracy on cylindricity evaluation. The method can also be extended for solving difficult form error minimization and profile evaluation problems of various geometric parts in engineering metrology.     

曲面笔式加工刀位点曲线的实时拟合

针对曲面高速高精度加工问题,给出一种刀位点轨迹实时生成算法。该方法的实现包括曲面上离散刀触点的生成和基于三次非均匀B样条曲线的刀位点轨迹实时高精度拟合两部分。第一部分,由导动曲线和刀触点轨迹的运动学关系,通过计算导动曲线参数,间接得到投影在曲面上的离散刀触点;第二部分,通过合理参数化、构建模长因子等实现刀位点参数曲线的分段实时拟合。仿真实例表明该算法简单易于编程,曲线拟合精度高,适用于自由曲面笔式加工中刀具路径计算与生成,从而满足复杂曲面高性能数控加工需求。     

Using genetic algorithms for the optimization of mechanisms

This work examines the possibility of using genetic algorithms for the optimization of the loads transmitted in mechanisms. The variables of design are the relative positions of the various connections, considered in a comparative manner. The minimization of the loads transmitted in the connections is achieved by optimizing the respective positions of those lead to less expensive solutions for bearings and sections of beams. The examples show that using this stochastic method is an efficient way to minimize loads in mechanisms.     

A method for the selection of algorithms for form characterization of nominally spherical surfaces

This paper presents a method for the selection of algorithms for the form characterization of nominally spherical surfaces. The form characterization is applied to discrete data obtained from a three-dimensional (3-D) high-precision measurement system. In this paper, five sphere-fitting algorithms are outlined and compared. The fitting algorithms under investigation are: linear and nonlinear least-squares sphere fit, minimum zone sphere fit, four-point sphere fit, and sphere fit by error curve analysis. A method for selection of the best-fit algorithm, based on a spectral analysis of the surface irregularity is suggested and applied to the surface measurement of worn electrical switching contacts.     

Method for assessing the similarity and distance between curves/trials and its applications in gait analysis

In clinical assessment or sports exercise.it is common that a subject is required to repeat a specific per-formance so that a stable movement pattern is obtained and analysed.In practice,however,the trials done by a sub-ject vary more or less,depending on the psychological or physical conditions.Some of the trials can be used as rep-resentatives of the stable movement pattern,and some not.Therefore,there is a demand for a new method to identify which trials/curves are similar.The traditional methods used to assess curve similarity are not perfecfly suitable for the case where there are only a few of trials available.This study proposes a similarity-distance coefficient to assess the similarity of curves/trials.A group of designed curves are used to validate the coefficient.The results show that given joint kinematic data during gait as examples,tlle proposed coefficient call be used to quantitatively evaluate the similarity of trials,and thus find which trials would be representative(S)for the gait investigated.The proposed method could be applied in various situations where repeat movements have to be measured and analysed.     

基于遗传算法的燃气涡轮发动机循环优化

遗传算法（Genetic Algorithms简写GA）是用于优化问题的新的有用的工具,其运用了自然界中的法则并且在可能的解空间上形成多点逼近的评价工具。遗传算法的特性使他能够有效的运用在发动机的设计工作中。论文的工作就是得出了基于要遗传算法的燃气涡轮发动机循环的优化。论文分为几个不同的部分,首先是关于GA的概要描述和主要架构。（初始群体的建成、每个个体的适应值评价、发展新一带的标准：成员的选择、繁殖、变异等等）,其次是用GA的应用程序优化燃起涡轮发动机循环和相关问题,文章最后介绍了单目标和多目标发动机循环优化的例子。