基于三次Bezier曲线的大型薄壁结构随机偏差场分布表征方法  

Random Deviation Field Description Method for Large Thin-walled Structure Based on Cubic Bezier Curves

作　　者：郭磊[1] 余海东[1] 宋建岭 来新民[2] GUO Lei;YU Haidong;SONG Jianling;LAI Xinmin(Shanghai Key Laboratory of Digital Manufacture for Thin-walled Structures,Shanghai Jiao Tong University,Shanghai 200240 China;Key Laboratory of Mechanical System and Vibration,Shanghai Jiao Tong University,Shanghai 200240,China;Tianjin Changzheng Rocket Manufacturing Co.,Ltd,Tianjin 300462,China)

机构地区：[1]上海交通大学,上海市复杂薄板结构数字化制造重点实验室,上海200240 [2]上海交通大学机械系统与振动国家重点实验室,上海200240 [3]天津航天长征火箭制造有限公司,天津300462

出　　处：《机械设计与研究》2020年第4期92-98,共7页Machine Design And Research

基　　金：飞机后段自动精准对合技术与成套装备(2014ZX04001081)。

摘　　要：大型薄壁结构产品偏差由成形与加工回弹所致,结构的弱刚性造成每一点偏差对装配质量产生影响,目前仅采用装配区域局部关键测点很难精确描述其随机偏差场分布特征。本文提出一种基于整体结构离散关键点集的随机统计偏差来构建具有随机分布特征的大型薄壁结构空间偏差场的方法。首先给出大型薄壁结构偏差场的定义,研究薄壁结构偏差场的几何连续性和区域分布特点。基于曲面的离散点求解理想零件的曲面形状参数,采用三阶Bezier曲线拟合零件曲面的参数方程。根据Bezier曲线良好的控制性,将曲线控制点作为决定零件曲面形状的关键点,引入偏差的统计特征,利用曲面上关键点的偏差信息调整零件的表面形状,构造了具有不同初始偏差的零件整体偏差场。以贮箱的瓜瓣为例进行了零件偏差场表征的案例分析,并验证了该方法的合理性和可行性。The deviation of large thin-walled structure is the results of the spring-back deformation.The assembly quality will be influenced by the deviation of every point on parts because of the weakness stiffness of the structure.It is difficult to describe the random deviation field of parts with few nodes on the surface.Therefore,a method to construct the space deviation field which is randomly distributed of large thin-walled structure based on random statistical deviation of the discrete points on the surface is proposed.Firstly,the deviation field continuity and the regional distribution of the thin-wall structure are analyzed due to the definition of the deviation field.Secondly,the cubic Bezier curves are used to fit the part surface parametric equations by using the shape parameters of standard parts which are deduced with discrete points on the parts.According to the adjustability of Bezier curves,the control points on Bezier curves are regarded as the key points on parts to describe the surface shape.Then the part surface shape is adjusted and the deviation field of the large thin-wall structures is ultimately described with key points on parts while the statistical characteristics of the deviation are introduced.Finally,taking the deviation description of the tank melon petal as an example to verifythe rationality and feasibility of the method.

关 键 词：偏差表征 偏差场 统计特性 BEZIER曲线 关键点集 

分 类 号：TH161[机械工程—机械制造及自动化]