【作者】 徐晓梅；

【导师】 胡泓；

【作者基本信息】 哈尔滨工业大学 ， 机械电子工程， 2010， 博士

【摘要】 表面粗糙度是描述表面微观形貌最常用的参数之一,是表面质量的直接反映,它在很大程度上影响和决定着零部件的使用性能,这种影响作用在机械、电子、生物医学和光学等诸多领域都有重要体现。近几十年来表面粗糙度测量问题一直是学术界重要的研究课题之一,随着产业发展的推动和新技术的引入,各领域内发展出许多新的测量方法。本文对各类典型的表面粗糙度测量方法进行了综述分析,针对目前内表面粗糙度测量技术的研究现状和反射式强度调制型光纤传感器(Reflective Intensity Modulation Fiber Optical Sensor, RIM-FOS)测量表面粗糙度存在的主要问题,以Φ5mm、Φ8mm和Φ10mm的孔为研究对象,提出了一种基于新结构的RIM型光纤内表面粗糙度传感器的测量方法,能够实现较小尺寸的孔内表面粗糙度的非破坏性测量。本文对RIM-FOS的工作原理进行了深入的理论研究,推导了一定假设条件下单光纤对的光强调制函数,从理论上分析了RIM-FOS强度调制特性曲线的主要影响参数,并对强度调制特性曲线的主要特性参数进行了解释,指出了表面粗糙度测量应用对应的目标特性。根据RIM-FOS强度调制特性的计算机仿真分析结论,确定了RIM型光纤表面粗糙度传感器设计的基本参考原则,设计了一种“1入12出”的双层同轴结构的光纤表面粗糙度传感器(传感器I)。利用微反射棱镜对传感器I的传感头进行结构改进,研制出一种RIM型光纤内表面粗糙度传感器(传感器II)。在RIM-FOS强度调制特性的建模研究中,光纤出射光强的分布假设若与实际情况不符,会直接影响模型的正确性和准确性。本文推导了光纤出射光强符合高斯分布假设下的单光纤对光强调制函数,并在反射面为理想镜面条件下建立了传感器I的强度调制模型。深入研究粗糙表面的散射特性,基于Beckmann的散射几何模型,推导了粗糙表面的光强调制函数。立足本文设计的双路输出的光纤表面粗糙度传感器,给出了RIM-FOS测量表面粗糙度的理论模型,可以实际指导表面粗糙度测量。最后针对孔内侧表面的测量问题,讨论了工作距离控制和传感头偏心等问题对测量结果的影响,为孔内表面粗糙度的测量提供了技术指导。基于理论分析的结论,本文对传感器I和传感器II的强度调制特性进行了实验研究,分析了两个传感器与表面粗糙度测量应用相关的特性,验证了光纤表面粗糙度传感器设计原则的合理性。通过传感器I和传感器II强度调制特性曲线的对比分析,实验研究了微反射棱镜对传感器应用特性的影响,结果表明传感器II在表面粗糙度测量方面有良好的应用能力。通过大量的实验,重点研究了反射面的表面粗糙度大小、加工方式和表面形状对传感器II强度调制特性的影响。实验结果表明,以传感器双路输出之比定义的测量参数对表面粗糙度有很好的区分能力,并通过分析确定了表面粗糙度测量时工作距离的取值范围;而反射面的加工方式和表面形状对传感器的输出有不同程度的影响,因此在对不同加工方式和不同表面曲率样本进行测量时要区别对待,分别标定测量曲线。应用传感器II,本文搭建了一套孔内表面粗糙度的光纤传感测量系统,对不同直径的孔进行了非破坏性测量。测量结果与TimeSurf TR220型触针式粗糙度仪的测量结果作了对比分析,论证了测量模型的正确性和测量方法的有效性、测量精度及测量范围,分析了测量结果的主要影响因素,指出了今后研究的努力方向。本文研制的反射式强度调制型光纤内表面粗糙度传感器不仅体积小、操作简便和经济性好,而且具有测量精度高和测量范围大的特点。因此,本文提出的基于该传感器的新测量方法将在较小零件内表面粗糙度的非破坏性测量方面具有很好的应用前景。更多还原

【Abstract】 Surface roughness reflects surface quality directly, which is one of the most commonly used parameters that describe the surface topography. It determines the working performance of parts in many fields, such as mechanical, electronic, biomedical and optical industries. Surface roughness measurement has long been a hot issue for researchers in the last several decades. With the development of industries and adoption of new technologies, increasing numbers of measurement methods have been proposed in every field. Some classical surface roughness measurement methods have been reviewed in this dissertation. The development of the inner surface roughness measurement techniques is analyzed. And the problems about the applying of RIM-FOSs in the surface roughness measurement are discussed. A new measurement method based on a novel RIM fiber optical inner surface roughness sensor is proposed. The method can nondestructively measure the inner surface roughness of holes with small diameters such as 5mm, 8mm and 10mm.The working principle of RIM-FOS is fully studied in theory. A new intensity modulation function of a single fiber pair is derived under certain assumptions. The main influence factors of the RIM-FOS intensity modulation characteristics are analyzed theoretically. And the characteristic parameters closely related to surface roughness measurement are explained and introduced. According to simulation conclusions, basic design principles of the RIM fiber optical surface roughness sensor have been determined finally. Consequently, a sensor that is coaxial, two-double, and“1input 12 outputs”is primarily designed (named Sensor I).On the basis of Sensor I, a micro prism is utilized, and the novel inner surface roughness sensor is developed (namely Sensor II).The intensity modulation model will be affected directly by the distribution assumption of emission intensity. Then the intensity modulation function of a single fiber pair is derived as the emission intensity is Gaussian distribution. And the intensity modulation function of Sensor I is established assuming that reflective surface is an ideal mirror. Besides, scattering of a rough surface is studied deeply. The intensity modulation function of a rough surface is derived on certain conditions based on the Beckmann’s scattering geometry model. Then a theoretical model of RIM-FOS for surface roughness measurement is proposed, which can guide the surface roughness measurement effectively. Finally, as to the inner surface roughness measurement of holes, the controlling of working distance and bias of the sensor head are discussed and analyzed qualitatively.Based on the conclusions of theoretical analysis, the intensity modulation characteristics of SensorI and SensorII have been studied experimentally. Characteristics that are relevant to surface roughness measurement are analyzed. Comparative analysis on characteristic curves of two sensors shows the influence of the micro prism. And the results show that SensorII has good capability in surface roughness measurement. The influence of the reflective surface to the characteristics of SensorII has been analyzed by abundant experiments. The factors include roughness value, machining method and shape of the surface. The experiment results show the defined measurement parameter by two outputs of the sensor can distinguish surfaces effectively. Simultaneously, the proper range of the working distance is found. However, the machining method and shape of the reflective surfaces affect the sensor characteristics to varing degree. Hence, when surface roughness is measured by a RIM-FOS, surfaces with different machining methods and curvature radius must be measured respectively.A surface roughness measurement system based on the designed Sensor II is set up. The inner surfaces of holes with different diameters are measured non-destructively. The measurement results are compared with those obtained by a TimeSurf TR220 roughness instrument. The measurement validity, accuracy and range of the proposed measurement method are verified and discussed, some main influencing factors are analyzed, and some future tasks are figured out.In conclusion, the study shows that the designed RIM fiber optical inner surface roughness sensor is not only small, simple and economical, but also with a high accuracy and a large measurement range. Therefore, its wide applications for non-destructive inner surface roughness measurement of relative small parts can be expected.更多还原