六自由度并联机构精度分析及其综合方法研究

发布时间：2018-05-04 16:31

本文选题：六自由度并联机构 + 位姿精度分析　；参考：《哈尔滨工业大学》2015年博士论文

【摘要】：随着工业技术的进步,并联机构的应用领域在逐步地拓展。然而,并联机构的生产制造仍然面临一系列难题,精度质量控制就是其中之一。在对国内外文献分析和研究基础上,本文以六自由度并联机构为研究对象,从制造和装配中出现的实际问题出发,围绕位姿精度分析和综合两方面内容展开研究。本文建立了六自由度并联机构误差模型,研究了动平台在给定工作区域内,位姿误差的分布形态。在并联机构精度分析中,国内外学者主要基于Monte Carlo方法对位姿误差统计参数进行估计,针对分析过程存在的计算精度和效率之间的矛盾,本文提出了基于Sobol序列的拟蒙特卡洛模拟的位姿精度分析方法。与传统的蒙特卡洛方法对比,该方法可显著地提高位姿误差统计参数的计算精度和效率。针对球域约束下,位姿误差概率难以直接求解的问题,本文推导并得出位姿误差概率积分方程的近似形式,得到位姿误差概率随球域半径的变化规律。结合并联机构实际装配阶段,动平台中心位置和姿态角偏差的控制要求,分析了铰链中心沿水平方向定位误差所具有各向同性特点,研究了位姿误差标准差之间的关系,推导并发现了在对称位姿状态下,动平台中心位置和姿态角偏差分别服从Rayleigh分布,并得到了中心位姿偏差概率随运动平台高度的变化规律。铰链间隙误差是导致并联机构位姿误差的一项重要的随机因素。在并联机构的工作区域内,为获得铰链间隙对位姿精度构成的影响,本文首先运用计算机仿真试验和均匀设计理论,对位姿精度敏感度进行显著性分析,找出影响显著的位姿参数。通过简化铰链结构,建立了并联机构冗余结构模型,应用正向运动学方法分析了传统概率分析方法在计算随机位姿误差方面存在问题。分析并提出了基于正向运动学的确定方法,研究了给定工作区间内位姿随机误差分布形态以及铰链间隙变化对位姿精度的影响,结论支持了精度敏感度的分析结果。围绕并联机构中心位姿随机偏差检测过程。应用基于正向运动学的确定方法和概率方法进行精度分析,得到了中心位姿随机偏差随动平台高度的变化曲线,同时指出了两种方法的联系和区别。结合生产现场中并联机构制造装配的实际情况,分析了精度综合方法存在的问题,认为精度综合应以现场的工艺能力为基础,形成以装配性能作为衡量指标的可行方案集合,提出了一种基于正交设计和均匀设计相结合的六自由度并联机构精度综合方法。首先以现场的工艺能力和经验参数为基础,进行正交设计,得到影响精度的诸多因素敏感度排序,以此为依据重新划分各项影响因素的水平,然后进行均匀设计,得到了具有全局意义的精度综合方案集合。该方法通过对结构参数公差的积极协调,能够避免单一优化方案存在的失效可能。对比分析结果表明:本方法得到的部分方案所对应的公差得到不同程度的放大。最后,结合本文部分研究内容,开发出六自由度并联机构精度分析及其综合系统,并进行了应用验证。
[Abstract]:With the progress of industrial technology, the application field of parallel mechanism is gradually expanding. However, the production and manufacture of parallel mechanism still faces a series of difficult problems, and the quality control of precision is one of them. On the basis of literature analysis and research at home and abroad, this paper takes six degrees of freedom parallel mechanism as the research object, and appears from the manufacturing and assembly. In this paper, the error model of the six degree of freedom parallel mechanism is established, and the distribution pattern of the position and posture error of the moving platform in a given working area is studied in this paper. In the accuracy analysis of the parallel mechanism, the scholars at home and abroad are mainly based on the Monte Carlo method for the pose error statistics. According to the contradiction between the calculation precision and the efficiency of the analysis process, this paper presents the position and posture accuracy analysis method based on the Quasi Monte Carlo simulation based on the Sobol sequence. Compared with the traditional Monte Carlo method, this method can significantly improve the calculation accuracy and efficiency of the statistical parameters of the pose error. In this paper, the probability of position error is difficult to be solved directly. In this paper, the approximate form of the probability integral equation of position error is derived and the variation law of the position error probability with the radius of the sphere is obtained. The control requirements of the central position and attitude angle deviation of the moving platform are combined with the actual assembly stage of the parallel mechanism, and the square of the hinge center along the water square is analyzed. The relationship between the position error standard deviation is studied and the relationship between the position error standard deviation is studied. It is found that the center position and the attitude angle deviation of the moving platform obey the Rayleigh distribution in the symmetrical position and pose state, and the variation of the probability of the central pose deviation with the height of the motion platform is obtained. The gap error of the hinge is caused by the hinge gap error. In the working area of the parallel mechanism, in order to obtain the influence of the position precision of the hinge clearance in the working area of the parallel mechanism, this paper first uses the computer simulation test and the uniform design theory to analyze the accuracy sensitivity of the position and position, and find out the prominent position and attitude parameters. By simplifying the hinges. The redundant structure model of the parallel mechanism is established, and the forward kinematics method is used to analyze the problems in the calculation of random position and pose errors by the traditional probability analysis method. The method of determining the random error distribution in the given working interval and the hinge gap change is studied. The results of precision sensitivity are supported, and the results of precision sensitivity are supported. The accuracy analysis is carried out based on the determination method and probability method based on forward kinematics based on the positive kinematics of parallel mechanism. The variation curve of the random deviation of the central pose with the height of the moving platform is obtained. At the same time, the combination of the two methods is pointed out. According to the actual situation of the manufacturing and assembly of parallel mechanism in the production site, the problems existing in the precision synthesis method are analyzed. It is considered that the precision synthesis should be based on the process capability of the field, and forms a feasible scheme set with assembly performance as a measure index, and puts forward a six self based on the combination of orthogonal design and uniform design. The precision synthesis method of the degree parallel mechanism is based on the process capability and the experience parameters of the field, and the orthogonal design is carried out, and many factors sensitivity order of the influence precision are obtained. On this basis, the level of the influence factors is redivided, then the uniform design is carried out, and the comprehensive set of precision comprehensive scheme with the global significance is obtained. Through the active coordination of the structural parameter tolerance, the method can avoid the failure possibility of the single optimization scheme. The results of comparison and analysis show that the corresponding tolerance of some schemes obtained by this method is magnified to varying degrees. Finally, the accuracy analysis and synthesis of the six degree of freedom parallel mechanism are developed with the content of this part of this paper. The system has been verified by application.

【学位授予单位】：哈尔滨工业大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TH112

【引证文献】