【作者】 王伟丽；

【导师】 范光照；

【作者基本信息】 合肥工业大学 ， 精密仪器及机械， 2008， 博士

【摘要】 超精密加工技术的高速发展,引发器件微型化革命,对相应三维检测设备的测量精度提出更高要求,三坐标测量机为传统通用性高精度测量仪器,发展尺寸小型化、精度纳米级,是微小型三坐标测量机研究中的关键技术。本文根据作者近年所参与的课题,针对小型三坐标测量机主体机台、精密二维定位工作平台、接触式测头系统等重要组成系统加以设计与研究,以确实掌握从设计、制造到测试各阶段的自主性关键技术。提出新型的拱形桥架结构取代传统直梁式桥架,结构具有高度的对称性,刚性好,具有更好的稳定性,桥架中心载重变形仅为传统结构的1/3;动态谐响应下,位移幅值变化小,在测量过程中具有高可靠性。基于优化设计理论,进一步提出塔形桥架结构,具有更好的空间立体对称性,为微纳米测量提供良好的测量参考面。针对精密二维定位平台的研究提出共平面概念,使得运动导轨面、一维光栅测量面和被测件所在平台面在同一高度,减小Z向阿贝误差和累积误差,兼顾对称设计和低膨胀系数材料的选择,减小载物平台的力变形、热变形。整合高分辨率一维激光衍射光栅测量系统和纳米电机驱动系统,二维平台可实现25mm×25mm的行程,定位重复精度优于30nm,驱动分辨率可达1nm。实现真正三维形貌测量有赖于接触式测头技术的发展,本论文研究中提出一种结合光学测量方法和机械传动与接触为一体的测头机构。测头系统包括光学传感器、位移传动机械悬架机构和测杆测球。基于DVD激光读取头,根据其光学聚焦原理开发非接触式聚焦探头系统,用以构成接触式测头系统中的位移传感器,测量范围为2μm,分辨率可以达到0.8nm/mV;通过理论计算与软件仿真提出新型悬挂机构,将测球的水平位移转为垂直位移,由DVD感测。四路DVD的应用放大信号改变量、有效消除信号噪声与漂移;测杆测球的研究提出以光纤为材料研制一体化测球的加工手段,基于熔接机电极尖端火花放电原理使玻璃光纤末端短时间熔化,由于表面张力而收缩的物理现象,使光纤末端自然形成微小圆球。采用“田口”科学实验计划法优化光纤熔烧过程的参数,进而控制光纤球的几何形状特性,得到直径310μm,真球度和偏心距离小于1μm的光纤球头,并且封装后用于接触式测头系统。此接触触发式测头系统通过实验证明:单方向测量重复精度小于10nm,XOY平面内预行程改变量小于15nm,XOY平面内测力平均值为110μN,Z方向测力平均值为59μN。可适应一定条件下微小工件的尺度测量。本文已经研究开发的上述机械结构与测头系统已分别应用于“非接触式纳米三坐标测量机”和“接触式纳米三坐标测量机”中,是纳米级三坐标测量机研究中的重要组成部分。更多还原

【Abstract】 With the development of ultra-precision machining technology, 3D measuring machines with high resolution are needed to meet the miniature components. Coordinate Measuring Machines (CMMs) with small size and micro/nano meter resolution are developed via breaking through the bottleneck. Based on the projects of developing micro/nano CMM, the author focused on the research of mechanical bridge, the precision 2D positioning stage, and the touch trigger probe system. Independent experiences from designing, processing and testing of every system constitute the important part during the research.Innovative arch-bridge structure was proposed to replace the conventional rectangular-bridge structure. The arch-bridge structure has much better stability; the deformation because of pressure coming from Z-spindle was decreased more than 1/3. Harmonic analysis results proved its superior dynamic performance. Finite Element Analysis (FEA) and optimization method were extended employed in this research, a pagoda-bridge was developed to strength its rigidity and stability because of the symmetry in space. Both the bridges supply metrology referring base for the precision measurements. Coplanar concept was developed during the research of the 2D precision positioning stage. It means the guide planes in X- and Y- are in the same height, as well as the measuring plane and the plane of workpiece carrier. As a result, the Abbe’s error and the cumulative error can be reduced. The symmetric structure is another highlight in this design to eliminate the structure deformation by force and temperature change. The stage was driven by nano motor with nanometer resolution and its displacement was detected by precision Linear Diffraction Grating Interferometer (LDGI). Experimental results show that XY stage can travel 25 mm with 1nm resolution and the positioning repeatability is less than 30nm.Conventional CMMs restrict the possibilities for measuring micro mechanical products and noncontact optical measuring methods are not suitable for true three-dimensional measurements. The integrated combination of optical sensors and mechanical transducers employed in this research makes an ideal low cost and high precision touch trigger probe possible to measure miniature components. This touch probe is composed of a stylus with a fiber sphere and a sensor integrated floating plate. The ball tip is fabricated using optical fiber with melting and solidification processes. Based on Taguchi method, the fusing process parameters are optimized. Fine fiber sphere with 310μm diameter and less than 1μm roundness and center offset can be fabricated. The stylus is attached to a floating plate, which is connected to the probe housing via four micro wires. The shape and dimension of the floating plate, as well as the length and diameter of the micro wire, are determined according to the selected contact forces. When the probe tip is displaced the wires will perform elastic deformation and four mirrors mounted onto the four-legged plate will amplify the up/down displacement at each mirror position. These displacements can be detected by four corresponding laser focus probes based no DVD pickup heads. Experiments were carried out to test the characteristics of the touch trigger probe. The standard deviation of unidirectional touch trigger repeatability is less than 10nm. The pre-travel variation along 360°in XOY plane is less than 15nm. The average trigger force is 110μN in XOY plane and 59μN in Z-direction when the threshold voltage is 10mV.The mechanism systems and touch trigger probe system developed in this thesis have been integrated in the projects of Non-contact Nano-CMM and the Nano-CMM with touch trigger probe.更多还原