面向复杂环形结构产品的装备偏差建模方法研究

发布时间：2018-09-07 08:33

【摘要】：复杂环形结构产品的应用相当广泛,具有回转对称、几何形状耦合、整体尺寸较大、局部结构复杂的特点。由于产品的普遍特性以及对功能的特殊要求,环形零件的质量评价方式不同于一般的薄板零件或者其他形状的零件,圆度、平行度、支板的角向分布均匀度等形位误差是质量评价必须控制的对象。形位误差的考虑导致环形零件的质量评价体系中测点与功能尺寸的数量十分惊人,测量效率低下。同时由于传统的偏差分析算法较少考虑形位误差的因素,现阶段还缺乏一个针对环形零件的可行的偏差分析体系,在实际的生产过程中,缺乏对环形零件质量评价的理论模型,导致难以实现生产前对批次产品质量的预测以及故障的诊断。针对复杂环形结构产品这一特殊对象所带来的偏差分析的诸多问题,本文首先对环形零件定位稳定性以及定位的自由度限制程度进行了推导,为环形零件定位优化提供了理论支持;然后基于优化的定位方式提出了一种极坐标系下针对复杂环形结构产品偏差分析的确定性定位偏差分析算法,统一了环形零件的坐标系与定位方式的表征方式;最后将该模型的装配偏差计算结果与零件的形位误差联系起来,建立了针对环形零件的关键形位误差求解模型并将提出的理论模型并在某大型复杂薄壁铸件上进行实践应用。本文的主要研究工作如下: 1)提出了针对复杂环形结构产品的生产组装过程的定位方式量化表征方法,为定位方式的优化选择提供了理论依据。基于确定性定位夹具偏差模型,推导了定位方式稳定性参数表达式。将机器人学中自由度限制度引入定位方式分析中,推导出定位雅可比矩阵病态指数表达式。通过这两个定位方式量化表征参数,对环形零件定位方式优化选取进行了实例分析。 2)根据复杂环形结构产品的功能特点,建立了针对于复杂环形结构产品的基于极坐标系下的确定性定位偏差分析模型以极坐标系作为工具,改进传统的确定性定位偏差分析模型,避免了在线性偏差与角向偏差转换过程中,由于坐标系与定位方式之间的耦合关系以及坐标变换的数学计算所带来的偏差。简化了模型的输入操作,提高了偏差分析的计算效率。 3)提出了新的形位误差表达方法建立了基于极坐标系下的圆度计算模型与面角向偏差计算模型,该模型可根据极坐标系下复杂环形结构产品偏差分析模型计算出来的测点径向与角向偏差,直接对复杂环形结构产品的圆度、平行度、支板角度均匀度等形位误差进行评价,将偏差分析模型与形位误差评价联系起来。 4)大型薄壁环形铸件上进行了偏差分析实例应用对某大型薄壁环形铸件蜡模组装过程进行了全过程的偏差分析,对蜡模定位方式进行优化,设计与优化了蜡模的测点与功能尺寸;求解关键测点的径向偏差与角向偏差,对大型薄壁环形铸件蜡模组装过程的法兰圆度与支板角度均匀度进行评定。分析结果表明,本文模型能够很好的进行偏差区域预测以及快速故障诊断,使得工程上环形件的质量评价效率得到了提高。
[Abstract]:Complex annular structure products are widely used, which have the characteristics of rotational symmetry, geometric coupling, large overall size and complex local structure. The angular distribution uniformity isomorphic error of support plate is the object that must be controlled in quality evaluation. The number of measuring points and functional dimensions in the quality evaluation system of annular parts is astonishing and the measuring efficiency is low due to the consideration of the geometric error. A feasible deviation analysis system for annular parts lacks a theoretical model for evaluating the quality of annular parts in the actual production process, which makes it difficult to predict the quality of batch products and diagnose faults before production.
Aiming at the deviation analysis problems caused by the special object of complex annular structure products, this paper firstly deduces the stability and degree of freedom restriction of annular parts positioning, which provides theoretical support for the optimization of annular parts positioning, and then proposes a pin in polar coordinate system based on the optimized positioning method. For the deterministic positioning deviation analysis algorithm of the product deviation analysis of complex ring structure, the coordinate system and the representation of the positioning mode of the ring parts are unified; finally, the assembly deviation calculation results of the model are linked with the shape and position errors of the parts, and a key shape and position error solution model for the ring parts is established and put forward. The theoretical model is applied to a large complex thin-walled castings. The main research work of this paper is as follows:
1) A quantitative characterization method of positioning mode for manufacturing and assembling process of complex ring structure products is proposed, which provides a theoretical basis for the optimization of positioning mode.
Based on the deviation model of deterministic positioning fixture, the stability parameter expression of positioning mode is deduced, and the ill-conditioned exponential expression of positioning Jacobian matrix is deduced by introducing the degree of freedom in robotics into positioning mode analysis. Example analysis.
2) According to the functional characteristics of complex ring structure products, a deterministic positioning deviation analysis model based on polar coordinates for complex ring structure products is established.
The traditional deterministic positioning deviation analysis model is improved by using polar coordinate system as a tool to avoid the deviation caused by the coupling relationship between coordinate system and positioning mode and the mathematical calculation of coordinate transformation in the process of linear deviation and angular deviation transformation. Rate.
3) put forward a new expression method of form and position error.
A model for calculating roundness and plane angular deviation based on polar coordinate system is established. The model can directly evaluate the roundness, parallelism and support angle uniformity of complex annular structure products according to the radial and angular deviation calculated from the product deviation analysis model of complex annular structure under polar coordinate system. The deviation analysis model is combined with the geometric error evaluation.
4) example analysis of deviation analysis for large thin-walled ring castings.
The whole process deviation analysis of wax mold assembly for a large thin-walled ring casting was carried out. The wax mold positioning method was optimized, the measuring points and functional dimensions of wax mold were designed and optimized; the radial deviation and angular deviation of the key measuring points were solved, and the flange roundness and the angle uniformity of support plate in the wax mold assembly process for a large thin-walled ring casting were studied. The analysis results show that the model can predict the deviation region and diagnose the fault quickly, which improves the efficiency of quality evaluation of ring parts.
【学位授予单位】：上海交通大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TH165.3

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