【作者】 史庆伟；

【导师】 张国雄；

【作者基本信息】 天津大学 ， 测试计量技术及仪器， 2007， 博士

【摘要】 本文设计并研制一台多轴联动的用于脆性回转体零件内外表面测量的三坐标测量机。测量机除能满足脆性回转体零件研究和生产对测量的要求,同时适应今后该类零件的形状变化的需要,兼有普通三坐标测量机的功能。本测量机能够实现的功能有:对内、外表面母线为各种复杂曲线的回转体零件的内外表面尺寸和形状进行自动测量;零件安放后,仪器能对被测件自动找正定心;整个测量过程自动进行,仪器能给出零件形状、被测参数与误差;存储测量数据,进行各种数据分析;测量机具有安全保护系统,防止意外事故发生。经过分析认为本测量机需要解决的关键技术有:工件内表面的同时测量问题,回转测量工件的定心问题,防碰撞保护问题,精度保证,内测、外测部件和转台三个坐标系的统一和标定技术等。为此设计了内测架倒置的移动桥式内表面测量机构、工件自动调偏定心机构、测头碰撞保护机构等多个有创新性的测量机构,研究了一系列标定技术。为了保证测量机在使用过程中的安全性,从多方面对安全可靠性进行了周密细致的考虑。设计了测量机安全监测系统,采用视觉识别技术监控测量的全过程;采用虚拟现实技术有效地避免测量机碰撞事故的发生;设计了多重限位保护机构,确保任一安全环节出故障后都有其它安全措施进行补救;采用非接触测量,防止和被测工件发生接触。本论文还详细研究了测量机的调整和校验方法,精度测试方法,误差补偿方法。进行了大量的实验,验证了测量机的性能。分析了误差产生的原因,对测量机进行误差补偿,使测量机的精度达到了设计要求。本论文的创新点主要体现在以下三点:1.针对零件的特殊性,提出了一种新的高可靠性,高安全性的测量机方案。包括:在无需翻转零件的情况下,实现工件内、外表面同时测量,在回转过程中连续测量,采用非接触测量等方案。研究了基于虚拟现实防止碰撞技术和视觉监测技术,研发了一系列碰撞保护技术等。2.研究了自动定心技术、自动平衡技术、卸荷式驱动技术、非接触测头抗干扰技术等一系列关键性的实用技术,提高了测量机的精度。3.研究了内、外测量部件和回转工作台坐标系的统一问题,研究了一系列标定技术,建立了统一的数学模型。更多还原

【Abstract】 A multi-axis CMM for measuring inner and outer surfaces of brittle rotational parts simultaneously is designed and developed in this thesis. The CMM meets the requirement for measuring specified rotational parts made of brittle materials and can be adapted to measuring parts with different forms, in addition, it also can function as a common CMM.The CMM can measure the inner and outer dimensions and forms of the rotational parts automatically; the generics of inner and outer surfaces might be all kinds of complex curves. After the part is mounted, the part can be centered automatically. The whole measuring process is automatic. The machine measures the forms, parameters and their deviations. The measured data are stored and analyzed. A safety protection system is built in the CMM and can prevent accidents effectively.The key technologies needed to be solved include measurement of the inner surface of the parts, centering problem of the parts; collision avoidance issues etc. In order to solve the above mentioned problems, an inverse moving bridge structure for measuring inner surfaces, a mechanism for centering the parts automatically, a set of collision avoidance measures and calibration techniques are creatively developed.Safety is of the most important problems in the design of the machine. Safety and reliability measures are taken from all possible aspects. A vision system is built to monitor the whole process including part loading, centering and measurement. Virtual reality technology is introduced to effectively avoid CMM collision accident occurrence. Multiple limiting and protecting mechanisms are developed. Supplemental measures come into action once any of the protection measures fails. Non-contact probes are used to avoid physical touches of the probes with the workpiece.The calibration, adjustment and performance testing approaches of the measuring machine are studied in detail. A large number of experiments have been carried out to verify the performance of the measuring machine. Errors sources are analyzed and error compensation is introduced to make the measuring machine meet the design requirements.The main creative ideals and innovations of the thesis include the follows.1. A special structure of CMM enabling simultaneous measurement of the inner and outer surfaces for the parts without access from the top for measuring the inner surface and not allowing being mounted horizontally is developed.2. The workpiece is measured by non-contact optical probes in the process of continuous rotation. Key technologies including the unification of three coordinate systems, establishment of unified mathematical model, system parameter calibration have been developed.3. A safety system, including vision system for monitoring the work process, collision avoidance and protection system, has been developed. The CMM is able to detect the foreign bodies during the loading and measuring processes, to check the correctness of the mounting discs, to recognize the types of the workpieces, to avoid the drop of the workpiece, to prevent and protect the part and mechanisms from collision. All these measures ensure high safety and reliability of the machine.更多还原