【作者】 何扬振；

【导师】 叶声华；

【作者基本信息】 天津大学 ， 测试计量技术及仪器， 2010， 硕士

【摘要】 曲轴与凸轮轴是汽车发动机中的重要零件,它们的质量直接影响发动机的性能。为了实现对它们的精确制造,需要有精密的测量设备来支持。传统的测量方法存在精度不高、伤害零件表面以及不能自动化检测等问题,已经不能满足测量需要。为了提高曲轴凸轮轴测量的精度与效率,本文研究设计了一种非接触测量头。其采用旋转平晶的方法实现激光对被测物的扫描,而采用PIN型光电二极管进行光电转换,通过测量时间间隔的方法间接测量物体的尺寸。这种方法能够在较大的范围内达到较高的测量精度。系统由光源、平晶、精密轴系、电机、光电探测器、信号处理等部分组成。本文的主要研究内容包括:1.分析常用的测量方法,根据测量要求提出一种合适的测量方法以适用于曲轴以及凸轮轴的测量。2.对系统进行分析,建立数学模型,给出具体的参数、设计要求以及硬件选型。3.设计接收器部分的反向偏压、跨阻放大以及时点判别等电路,保证信号沿的准确测量。4.使用FPGA设计系统的数字处理单元。5.对系统进行了误差分析,研究光束倾斜、平晶两端面不平行以及计时单元产生的误差,并根据测量要求提出了对这几个部分的要求。根据数学模型仿真得出测量出的时间与光束位移的关系曲线。6.对PIN管的信号处理电路板进行实验,以验证电路的功能。更多还原

【Abstract】 Crankshaft and camshaft are the important parts of the automobile engine, and their quality directly affects the performance of the engine. In order to achieve their precise manufacturing, precision measurement equipment is needed to support.Traditional measurement methods have some shortcomings such as accuracy is not high, damage part surface, can not be automated test and so on. So they can not meet the measurement needs. In order to improve the accuracy and efficiency of the crankshaft and camshaft measurement, this article study and design a non-contact measuring head. The method of rotating flat crystal is used to make laser beam scanning the measured object. PIN-type photodiode is used for photoelectric conversion. By measuring the time interval, the size of the object is measured indirectly. This method can achieve high accuracy in a large range. The system consists of light, flat crystal, precision shafting, electromotor, photoelectric detectors, signal processing components and so on.The main contents of this article are summarized as follows:1. The common measurement methods are analyzed, and an appropriate measurement method is introduced for the measurement of crankshaft and camshaft according to the measurement requirements.2. The system is analyzed; mathematical model is constructed, and the specific parameters, design requirements and hardware are given.3. The reverse bias voltage circuit, trans-impedance amplification circuit and time point discrimination circuit are designed to ensure accurate measurement of the signal along.4. The system error analysis is made. The effect generated by beam tilt, not paralleled flat crystal surface and time measurement on the measuring system is studied. According to the requirements of precision, demands is made on these components. According to the mathematical model, simulation is made to obtain the relationship between the time and the exit beam position.5. Experiment about the circuit board to process the signal of the PIN tube is made to verify the circuit functionality. ]更多还原