针对直纹面表面结构检测的探头六自由度定位方法研究

发布时间：2018-07-16 12:10

【摘要】：随着先进制造领域的不断发展,对零件的加工质量也相应的提出了更高的要求,表面结构作为表征零件加工质量的重要指标,对其进行准确有效的检测已经成为发展先进制造装备的重要前提。现有的表面结构测量技术虽可满足大多数零件的检测需求,但对于复杂直纹面类零件,如叶片、机翼、叶轮等制造领域中的重要零部件,在测量其表面结构时仍存在测量区域有限、无法定点测量、运动误差影响测量精度等局限性。针对上述问题,本文提出一种可定点检测直纹面表面结构的六自由度定位系统,并围绕其测量过程中探头的六自由度定位问题开展了一系列研究,本文主要内容包括:1.根据表面结构标准检测方法,结合直纹曲面的型面特征及侧铣加工机理,明确直纹曲面的表面结构检测方式;分析常用检测设备在测量直纹曲面过程中存在的探头空间干涉与定位问题,提出一种采用横向扫描探头检测直纹面表面结构的六自由度定位系统;针对探头实际定位姿态在绕X、Y、Z方向上存在角度偏差问题,采用数值求解方法分析各角度偏差对测量结果准确性的影响。2.根据探头六自由度定位需求,依据由直纹曲面参数方程定位待测点的处理方式,通过采用OpenGL三维建模技术并建立参数方程(u,v)坐标与UV纹理坐标的对应关系,提出一种基于模型交互的屏幕光标定位待测点方式,实现直纹面上待测点的直观定位及六项位姿信息的获取;针对其无法定点测量问题,进一步提出一种基于模型交互的数值输入定位待测点方式,通过采用人工输入待测点坐标的形式解决该问题。根据两种待测点定位方法的实现原理,分别对其中的模型文件读取、模型交互显示、三角面片拾取以及射线求交拾取点等算法做出设计。3.针对探头定点测量的实现问题,根据系统的运动控制模式,设计探头定位的运行流程;采用多体系统理论构建系统运动学模型,完成系统逆运动学分析,明确探头定位至待测点所需位移量;分别采用标尺和3D寻边器,完成系统机床坐标系原点与工件原点的设定,构建探头定位基准。4.基于VS2010、OpenGL接口及运动控制卡动态链接库,对控制软件进行开发,实现直纹曲面待测点定位及探头自动定位测量功能;并采用黑盒测试方法,完成软件各项功能的正确性测试。借助控制软件,分别开展定位系统的定点重复测量试验和回原点定点重复测量实验,以检验系统的定点测量精度。
[Abstract]:With the continuous development of the advanced manufacturing field, the machining quality of the parts is also put forward higher requirements, surface structure as an important indicator of the quality of parts processing, Accurate and effective detection has become an important prerequisite for the development of advanced manufacturing equipment. Although the existing surface structure measurement technology can meet the inspection requirements of most parts, but for complex straight surface parts, such as blades, wings, impellers and other important parts in the manufacturing field, There are still some limitations in measuring its surface structure, such as the limited measuring area, the impossibility of fixed-point measurement and the effect of motion error on measuring accuracy. In order to solve the above problems, this paper presents a six-degree-of-freedom positioning system which can be used to detect the surface structure of a straight surface. A series of researches have been carried out around the six degrees of freedom positioning of the probe in the measurement process. The main contents of this paper include: 1. According to the standard inspection method of surface structure, combined with the profile characteristics of straight surface and the machining mechanism of side milling, the inspection method of surface structure of straight grain surface is determined. This paper analyzes the spatial interference and positioning problem of the probe in the process of measuring the straight surface of the common detecting equipment, and puts forward a six degree of freedom positioning system which uses the transverse scanning probe to detect the surface structure of the straight surface. Aiming at the problem of angle deviation in the direction of the probe's actual positioning attitude, the influence of each angle deviation on the accuracy of measurement results is analyzed by numerical method. According to the requirement of probe positioning with six degrees of freedom, according to the processing method of locating the points to be measured by the parameter equation of straight line surface, the corresponding relationship between the parameter equation (UV) coordinate and UV texture coordinate is established by using OpenGL 3D modeling technology. In this paper, a method of screen cursor positioning to be measured based on model interaction is proposed, which can directly locate the points to be measured on the straight grain surface and obtain the information of six positions and postures, aiming at the problem that it can not be measured at a fixed point. Furthermore, a new method of numerical input location based on model interaction is proposed, which can solve the problem by manually inputting the coordinates of the points to be measured. According to the realization principle of the two methods, the algorithms of model file reading, model interactive display, triangulation and ray-intersection pick-up are designed respectively. According to the motion control mode of the system, the running flow of the probe positioning is designed, the kinematics model of the system is constructed by using the theory of multi-body system, and the inverse kinematics analysis of the system is completed. The displacement required for the probe to locate to the point to be measured is determined, and the system machine coordinate system origin and workpiece origin are set up by using the ruler and 3D edge-finder respectively, and the probe positioning datum .4is constructed. Based on the OpenGL interface of VS2010 and the dynamic link library of motion control card, the control software is developed to realize the function of locating the point to be measured on the straight surface and the automatic position measurement of the probe, and the correctness test of each function of the software is completed by using the black box test method. With the help of the control software, the fixed point repeated measurement experiment and the return point repeated measurement experiment of the positioning system were carried out to verify the accuracy of the system.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG80

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