【作者】 朱卫民；

【导师】 王大勇；

【作者基本信息】 北京工业大学 ， 光学工程， 2013， 博士

【摘要】 测量是人类获取信息的最重要来源之一，有效的测量必须是可靠的，是有溯源性的。溯源性是指任何一个测量结果或计量标准的量值，都能通过一条具有规定不确定度的连续比较链与计量基准联系起来，实现单位统一和量值统一。进入新世纪以来，随着和谐社会的建设，计量科学更加关注环保、医疗安全等民生计量，而光电测试技术以其高精度、高速度、远距离、大量程、非接触测量、便于信息的控制和存储、易于实现自动化等优势，成为计量溯源的重要手段。本论文应用光电测试技术对汽车排气污染物检测用底盘测功机（本文简称排气底盘测功机）的溯源进行了系统研究。首先，提出了校准方法，研制了校准标准设备--基于光电技术的滑行时间测试仪，研究了滑行时间测试仪的计量性能表征参数和校准方法，建立了汽车排气污染物检测用底盘测功机的溯源体系。其次，针对目前我国医用超声设备的输出安全检测的现状和问题，提出采取三维数字光学成像技术研究超声输出的瞬时峰值强度、峰值负声压、输出波束声强等声场参数。设计了三维数字光学成像技术测量声场的装置并作了理论分析，通过实验数据证明了方法的可行性。论文的主要工作包括以下几个方面：1、通过对汽车排气污染物检测检测用底盘测功机的常用结构及相关技术指标的分析，提出了在用汽车排气污染物检测用底盘测功机周期校准的项目、方法和校准条件。提出了排气底盘测功机基本惯量DIW的恒扭力两次加载法校准滑行时间。为防止在用汽车排气污染物检测用底盘测功机软件作弊，在恒加载滑行时间校准中，提出了预加载法校准加载滑行时间，并通过理论推导给出了表达式。最后，通过实验数据和测量结果不确定度的分析证明了本论文所提出的校准方法的合理性和正确性，且能够满足汽车排气污染物检测用底盘测功机校准和溯源的要求。2、根据本论文提出的汽车排气污染物检测用底盘测功机的校准方法，特别考虑到方法的溯源性，研制了基于光电技术的滑行时间测试仪作为标准设备。研制了一套在线实时数据采样处理系统，可对底盘测功机的速度、时间、力值等进行实时检测。采用两个高速光隔，对光电编码系统产生的信号进行有效的隔离，提高了抗干扰能力和工作稳定性，采用四倍频电路，提出了三次交叉平均值方法提高了滑行时间测量精度，既满足了速度判定准确性的要求，又消除了速度判定所用时间给滑行时间计时带来的误差。之后，通过试验和数据分析，证明了采取接触式采样器可使滑行时间测量仪和被校准汽车排气污染物检测用底盘测功机的速度同步性优于0.02%，滑行时间的测量误差优于±3ms。滑行时间的校准的测量结果不确定度小于底盘测功机规定的滑行时间的最大允许误差的三分之一，完全满足汽车排气污染物检测用底盘测功机的校准要求。3、为了完善汽车排气污染物检测的溯源体系，保证滑行时间测试仪的准确性，提出了表征滑行时间测量仪计量性能的校准溯源参数、研究了校准方法和校准条件。通过实验和数据测量不确定度分析，证明了本论文所提出的方法的合理性和正确性，满足校准和溯源的要求。4、为解决医用超声设备的输出安全的检测溯源问题，提出采取三维数字光学成像技术研究超声声场的方法。研究设计了测量系统，系统首先采取迭代算法由CCD得到的光强度图计算出超声脉冲刚通过声场后的相位图，当超声换能器沿着与入射光脉冲传播方向垂直的轴旋转180度时，通过层析算法重建光相位的三维图，并由相位、折射率和声压分布的关系，获得脉冲超声场的三维声压，通过计算可得到表征医用超声设备的输出安全的参数值。研究了GS迭代算法及其改进理论。研究相位图像的三维重建算法，提出了用Radon滤波反投影算法来进行三维图像重建处理，同时研究了在三维重建算法的数字实现过程中采样频率和滤波器的选择问题。推导计算了折射率和声压的关系式。最后，搭建了三维数字光学成像技术研究超声声场的实验装置，得出了初步实验结果，并和水听器扫描方法得到的结果进行了比较，数据分析表明结果的一致性好，表明三维数字光学成像技术测量超声场从理论和实际都是可行的，为进一步实现医用超声设备输出安全的光学检测打下了基础。更多还原

【Abstract】 Measurement is one of the most important sources for us to acquire information,and thus it must be reliable and traceable. A core concept in measurement ismetrological traceability, defined as the property of the result of a measurement or thevalue of a standard whereby it can be related to stated references, usually national orinternational standards, through an unbroken chain of comparisons, all having stateduncertainties. And this will unite unit and value. At present, livelihood measurement,such as those applied in environmental protection and medical care, is being paidgreat attention. Since photo-electronic hybrid technology has advantages in highprecision, long distance, wide range, non-contact measurement, easy for controllingand storing information and realizing automatic operation, it becomes an importantmeans of metrological traceability.This paper is a systematic study of the traceability of chassis dynamometers forautomobile emissions testing with photo-electronic hybrid technology. First of all, thispaper proposed a way to calibrate chassis dynamometers for automobile emissionstesting. Based on photoelectric technology, a standard instrument called coast-downtime tester is devised for calibration. Besides, the paper studies characteristicparameters of coast-down time tester and a way to calibrate coast-down time tester,and traceability system for chassis dynamometers for automobile emissions testing isestablished. Secondly, according to current situation of safety inspection to the outputof medical ultrasound equipment, a three-dimensional digital schlieren–technique isproposed to measure parameters of ultrasonic field, such as the maximum value of theultrasound instantaneous peak intensity, negative acoustic peak pressure, acousticintensity of beam. A device is designed and analyzed theoretically to measureultrasonic field using three-dimensional digital optical technology. The feasibility ofthis method is confirmed by experimental data. The main work in this paper isreported as the following:By analyzing structure and technical specifications of chassis dynamometers forautomobile emissions testing, the paper gives the characteristic parameters, calibrationmethods, standard set-ups and environmental conditions of ‘chassis dynamometers forautomobile emissions testing’ for the periodic calibration. Coast-down testing withtwice constant-force loading method, a new way to get the DIW (DynamometerInertia Weight) of chassis dynamometers, is proposed. To prevent cheating whenusing software of ‘chassis dynamometers for automobile emissions testing’ during thecalibration of coast-down time with constant-force loading, a preloading method isused and its theoretical formula is derived. Finally, the calibration method is proved tobe reasonable and accurate by experimental data and analysis of uncertainty of measurement results. The method can satisfy calibration and traceability requirementsof chassis dynamometers for automobile emissions testing.In this paper, according to the methods that we have proposed for calibration ofchassis dynamometers for automobile emissions testing, especially taking intoaccount its traceability, a coast-down time tester based on photoelectric technology isdeveloped as calibration standard equipment, and an on-line real-time data samplingprocessing system which can get speed, time interval, force value and otherparameters of chassis dynamometer in real-time is developed. Two high-speed opticalisolations that can isolate signals produced by optical encoder system effectively areused to increase the anti-interference ability and work stability of the coast-down timetester. Quadruple frequency circuit is devised to improve the measurement accuracy. Amethod that uses cross mean value three times to measure coast-down time is firstproposed in this paper. This method can not only satisfy accuracy requirements ofspeed determination, but also reduce the timing error caused by speed determinationtime. Making a study of the experimental data, the paper confirms that the coast-downtime tester with contact-type sampler can synchronize with ‘chassis dynamometers forautomobile emissions testing’ and their speed difference is less than0.02%, and theMPE of coast-down time is less than±3ms. The uncertainty of the measurementresult of coast-down time calibration is less than one-third of the MPE（maximumpermissible errors）of coast-down time that is prescribed in performance requirementsto chassis dynamometers. The uncertainty fully meets calibration requirements ofchassis dynamometers for automobile emissions testing.In order to better the traceability system of automobile emissions testing, theparameters that represent characterization are proposed for coast-down time tester. Atmeanwhile the calibration methods, standard set-ups and environmental conditions ofthe calibration are determined. By analysing the experimental data and uncertainty,the calibration methods proposed in this paper are proved to be correct and reasonable.It can satisfy calibration and traceability requirements.In order to solve traceability issues of safety inspection to the output of medicalultrasound equipment, a method using optical three-dimensional digital fringetechnology is proposed to research ultrasonic field. A measuring system is studiedand designed, which adopts iterative algorithm to calculate the phase distribution ofthe plane that ultrasonic pulse just passed the sound field through light intensitydistribution image obtained by CCD. When the ultrasonic transducer is rotated from0to180degrees along the axis that is perpendicular to the direction of propagationincidence pulse light waves, many phase distribution slices are gained. Thenthree-dimensional phase distribution map is reconstructed based on chromatographyalgorithm, and three-dimensional sound pressure distribution of pulsed ultrasound field can be gained according to the relationship between phase, refractive index andpressure distribution. Finally, the characterization security parameters of medicalultrasound equipment’s output can be obtained. The improved theory of GS iterativealgorithm and Radon filtered back projection reconstruction algorithm ofthree-dimensional phase images are researched. In addition, the methods of samplingfrequency and filter choosing in the process of three-dimensional reconstruction aredetermined. The relation between refractive index and sound pressure is derived andcalculated. Finally, an experiment device based on optical three-dimensional digitalstripe technology is set up to research ultrasonic sound field and to obtain preliminaryexperimental results. Comparing with the results by hydrophone scanning method,data analysis shows that the consistency of these results is satisfactory. It is provedthat3D stripes imaging technology method is feasible in both theory and practice. Thestudies in this paper provide a basis for further realization of optical safety inspectionto the output of medical ultrasound equipment.更多还原