【作者】 杨练根；

【导师】 李柱；

【作者基本信息】 华中科技大学 ， 机械制造及其自动化， 2004， 博士

【摘要】 表面形貌测量技术与评定理论一直是当今表面计量学的前沿课题。基于各种探测原理的表面形貌测量仪器存在着高精度和大量程的矛盾,研制一种高精度、大量程的表面形貌测量系统有着重大的意义和应用前景。针对表面形貌的测量和评定理论,本文的主要研究内容及创新如下:提出和研制了一种适合于工程表面形貌测量的大量程的微恒力位移传感器。该传感器由电感和音圈电机构成,传感器使用电感作标尺,而音圈电机作为控制测量力和扩大量程的机构。系统论述了传感器各个组成单元的设计和实现方法,通过理论分析建立了传感器测量力伺服控制机构的数学模型,分析了测量力控制的稳态误差和稳定性,设计了 PID 校正网络,并对传感器的动态特性进行了辨识、测试和数字仿真。提出了一种通过电感传感器提升扩大量程的算法。该算法已用于基于微恒力位移传感器的大量程表面形貌测量系统,使该测量系统具有 2mm 的测量范围和 0.02μm 的精度。为适应不同的测量速度和表面形貌变化的要求,系统有 5 个电感传感器提升的预设阈值。音圈电机的驱动采用 16 位 D/A 转换器,使音圈电机的控制精度提高。系统采用了新的光栅计数方法,利用光栅的多零位信号,使信号不致丢失,计数更准确可靠。分析了此测量系统存在的误差以及各项误差的影响,按照 ISO12179:2000 标准的要求,对测量系统的精度、测量范围、使用性能等进行了实验验证。提出了一种基于网格和有限差分的二维 Motif 合并算法。分析了二维和三维 Motif评定方法的发展现状,探讨了二维 Motif 合并试验解的唯一性和稳定性,将 Motif 合并表示为事件,对一组给定的事件集,所有可能合并的 Motif 的事件集都可以在一个网格中列举。采用基于有限差分的方法搜索 Motif 的峰和谷,进而编制了二维 Motif 评定软件,并将 Motif 评定软件和研制的大量程表面形貌测量系统融为一体,便于对测量 I<WP=4>结果进行Motif评定,并通过计算结果分析了Motif参数和传统粗糙度参数之间的异同。对目前公认的三维 Motif 的定义进行了比较,并引入数字高程模型和等高线的图论表示方法,对三维 Motif 的合并进行了探讨。更多还原

【Abstract】 In present-day surface metrology, surface morphology measuring techniques and assessmenttheories have always been the frontier research field. Owing to the discrepancy between thehigh precision and measuring range for surface measuring instruments based on variousmeasuring principles, it is of great significance to develop a high precision surfacemorphology measuring system with broad prospects for application. The main researchcontents and creative points about measurement techniques and assessment methods ofsurface topography in the dissertation are as follows:A displacement sensor with a wide measuring range and micro-constant measuring force hasbeen proposed and developed which is suitable for measurement of engineering surfacemorphology. The displacement sensor consists of an electric induction sensor and a voicecoil motor (VCM). The induction sensor is used as the measurement standard and the VCMis used to control measuring force and enlarge the measuring range of the displacement. Themethods of designing and implementing all the structural units of the displacement sensorare discussed at length. A mathematical model for the feedback control mechanism of thesensor’s measuring force is established based on theoretical analyses. The steady-state errorand stability of measuring force control are studied and a PID corrective controller isdesigned. The dynamic characteristics of the displacement sensor are discriminated, testedand digitally simulated.An algorithm for broadening the measuring range by lifting the inductance sensor isproposed, which has been used in a large-range surface morphology measuring system. Withthis algorithm, the precision of the measuring system has risen to above 0.02μm and itsmeasuring range to 2mm. In order to adapt to different measuring speeds and the variationof surface morphology, the system now has 5 predetermined measuring ranges of induction.The VCM is driven by a 16 bits D/A converter to improve the control precision. A new III<WP=6>count method for optical grating is adopted in the measuring system. In the counting methodof the measuring system, the multi-zero signal of the grating is utilized to prevent the signalfrom getting lost, making the count more accurate. The errors of the system and theirinfluence on the measuring system are analyzed. Experimental verification of the precision,measuring range and performance of the system are performed in accordance with therequirements of ISO12179:2000.A 2-D Motif combined algorithm is proposed based on finite difference and the latticetheory. The research progress of 2-D and 3-D Motif assessing method is studied.Following an analysis of the progress made in this method, the uniqueness and stability ofthe solution for 2-D Motif combined tests are discussed. With the Motif represented as anevent, all the given sets of events in which Motif can be combined may be enumerated in alattice. The 2-D Motif evaluating software has been developed by searching the peaks andvalleys of Motif method based on finite difference. The software is integrated with thelarge-range surface morphology measuring system, facilitating Motif assessment of theresults of measurement. The differences between 2-D Motif parameters and the roughnessof traditional 2-D standard are analyzed. The similarities and differences among the severalcurrently recognized 3-D Motif definitions are compared. Based on a digital elevationmodel and graph theory expression of contour, a 3-D Motif assessment algorithm isdiscussed.更多还原