High-accuracy ultrasonic temperature measurement based on MLS-modulated continuous wave

Ultrasonic temperature measurement has the potential to improve measurement accuracy by increasing the length of a received signal due to its excellent performance with noise resistance. However, when the distance between the transmitter and receiver is limited, the received signal can be polluted by strong multiple echoes, which can significantly degrade temperature accuracy. This paper proposes a method for high-resolution ultrasonic temperature measurement. With the use of a maximum length sequence (MLS)-modulated continuous wave, the obstructive effect of echoes is effectively suppressed. A hybrid method is employed for accurate time-of-flight (TOF) estimation by incorporating both cross-correlation and phase shift (PS), which is the basis of highly accurate temperature measurement. The experimental results in distilled water show that the proposed method estimates TOF with a standard deviation of less than 0.3 ns, and temperature errors consistently remain within ±0.04 °C.     

Measurement of the shape in the radioactive area by ultrasonic wave sensor

The HANARO (High-flux Advanced Neutron Application Reactor) has been operated since 1995. The Cold Neutron (CN) hole was implanted in the reflector tank from the design stage. Before a vacuum chamber and a moderator cell for the cold neutron source are installed into the CN hole, it is necessary to measure exactly the size of the inside diameter and thickness of the CN hole to prevent the interference problem. Due to inaccessibility and high radiation field in the CN hole, a mechanical measurement method is not permitted. The immersed ultrasonic technique is considered as the best way to measure the thickness and the diameter of the CN hole. The 4-Axis manipulator was designed and fabricated for locating the ultrasonic sensors. The transducer of an ultrasonic sensor having 10 MHz frequency leads to high resolution as much as 0.03mm. The inside diameter and thickness of 550 points of the CN hole were measured using 2 channel ultrasonic sensors. The results show that the thickness and inside diameter of the CN hole is in the range of 3.3 - 6.7mm and 0 156-165mm, respectively. This data will be a good reference for the design of the cold neutron source facility.     

Systematic experimental based modeling of a rotary piezoelectric ultrasonic motor

In this paper, a new method for equivalent circuit modeling of a traveling wave ultrasonic motor is presented. The free stator of the motor is modeled by an equivalent circuit containing complex circuit elements. A systematic approach for identifying the elements of the equivalent circuit is suggested. The Levenberg-Marquardt parameter estimation algorithm is used to model the alteration of the admittance after placing the rotor on the stator. Thereafter, theoretical assessments and experimental measurements are used to account for the speed reduction that is caused by placing the rotor on the stator and applying the load torque. Finally, the effects of temperature changes and the resultant response of the motor are computed. Results of the experiments and measurements are used to verify and validate the precision of the new modeling method.     

数字化超声波探头检测系统设计

运用计算机数字化技术建立了一套针对多种超声波探头性能指标的自动检测分析系统。详细阐述了构建该系统的关键技术,包括数字化超声波发射采集卡和运动控制卡的选用,软件系统的设计。该系统实现了超声波探头运动控制与数字化探头性能检测分析的集成,具有功能实用、操作简单、自动化程度高的特点,可为超声波探头生产厂家或探头使用者提供快速、准确、可靠的探头性能检测结果。     

Development of a high-precision and wide-range ultrasonic water meter

Ultrasonic water meters offer a number of advantages such as non-intrusiveness, low pressure loss, high accuracy, low power consumption and long service life, which make them a viable option for the next generation of smart water meters. However, the existing ultrasonic water meters have difficulties in balancing the range and accuracy. Therefore, in order to address this issue, this study proposes a novel ultrasonic water meter featured with high-precision and wide-range. First of all, the flow measurement principle of the ultrasonic time difference method is investigated, and a flow measurement model that includes the parameter of radial transit time ($T_D$) is developed. The ultrasonic water meter is designed based on comprehensive consideration of the three aspects of hardware, software and algorithms, and a series of experiments are conducted to verify the performance of the water meter. Eighteen verification test points with the flow range of 0.015–4.509 m³/h are carried out, the results of which suggest that the accuracy level of the ultrasonic water meter reaches 0.5, with the repeatability of 0.09%, and the range ratio of 300:1, indicating the achievement of the design goal of high-precision and wide-range.     

智能移动机器人超声波测距定位系统的研究

移动机器人技术是机器人研究领域的一个重要分支。为了赋予机器人智能控制和自主导航的能力,解决机器人开发过程存在着成本高、功耗大等问题,研究设计了一套基于超声波传感器的智能移动机器人测距定位系统,同时使机器人具有报警、避障及定位等功能。     

高温超声横波波速规律与影响因素研究

通过实验,得到了在-40℃-450℃范围变化内,超声波在16MnR钢内的横波传播速度值,按其趋势拟合了两种速度规律关系式,并对其进行了比较.讨论了由于热膨胀造成的试件半径的变化对速度测量误差的影响,给出了实际波速、量程修正和误差幅度关系式,修正了不同温度下波速实际值和缺陷的实际位置.分析了由于温度变化造成的弹性模量、泊松比和密度的变化对速度变化的影响,解决了目前在高温运行环境下压力容器与管道急需解决的问题.     

Neuro-fuzzy speed control of traveling-wave type ultrasonic motor drive using frequency and phase modulation

This paper presents a Fuzzy Neural Network (FNN) control system for a traveling-wave ultrasonic motor (TWUSM) driven by a dual mode modulation non-resonant driving circuit. First, the motor configuration and the proposed driving circuit of a TWUSM are introduced. To drive a TWUSM effectively, a novel driving circuit, that simultaneously employs both the driving frequency and phase modulation control scheme, is proposed to provide two-phase balance voltage for a TWUSM. Since the dynamic characteristics and motor parameters of the TWUSM are highly nonlinear and time-varying, a FNN control system is therefore investigated to achieve high-precision speed control. The proposed FNN control system incorporates neuro-fuzzy control and the driving frequency and phase modulation to solve the problem of nonlinearities and variations. The proposed control system is digitally implemented by a low-cost digital signal processor based microcontroller, hence reducing the system hardware size and cost. The effectiveness of the proposed driving circuit and control system is verified with hardware experiments under the occurrence of uncertainties. In addition, the advantages of the proposed control scheme are indicated in comparison with a conventional proportional-integral control system.     

带有温度自控装置的户用热量表流量计的设计

设计了一种在超声波热量表中用的测量管道。由于超声波测量管体、传感器安装孔、传感器穿线管和安装座在焊接为一体时,难以保证各部件的相互尺寸、位置精度要求,所以设计提出将以上结构一次铸造成型,并在实现一体化的基础上加装双金属测温器。由于采用一次铸造成型,所以精度高,便于大批量生产;由于加了双金属片测温器,及由其控制伸缩改变热水流量的方形板,可自动调控室内温度,可广泛用于取暖管的控制。     

Measurement of the contact area of a dovetail milling cutter using an ultrasonic method

Since there is no reliable mathematical model to analyze a multi-points contact simultaneously, the most effective way to know the contact area is to use experimental method directly. This study measures the contact area between a dovetail milling cutter and a steel plate by using ultrasound for regional scanning. This is a novel application for milling cutters and has not been applied before. The transducer emits an ultrasonic pulse to detect the contact surface. If contact occurs, the pulse is partially transmitted into the specimen. Therefore, the signal reflected back to the pulse receiver is reduced. The amount by which the signal amplitude is reduced is a measure of the degree of contact.     

Measurement of solid propellant burning rates by analysis of ultrasonic full waveforms

The measurement of solid propellant burning rates using ultrasound requires the simultaneous acquisition and analysis of ultrasonic signals and pressure data simultaneously in a wide range of pressure values during the process of propellant burning. Recently, this method has been proposed as an effective approach based on an analysis of full waveforms of ultrasonic signals together with a laboratory prototype system in which the proposed approach has been implemented. However, this prototype system had limitations in terms of data processing speed and signal processing procedures. To overcome such limitations, in the present study, we develop a dedicated, high speed system that can acquire ultrasonic full waveforms and pressure data up to 2,000 times per second. Our system can also estimate the burning rate as a function of pressure using a special software based on ultrasonic full waveform analysis. This paper describes the approach adopted in this high speed system, along with the burning rate measurement results obtained from three propellants with different burning characteristics. This paper was recommended for publication in revised form by Associate Editor Dae-Eun Kim Sung-Jin Song received a B.S. degree in Mechanical Engineering from Seoul National University, Seoul, Korea in 1981, a M.S. degree in Mechanical Engineering from Korea Advanced Institute of Science and Technology in 1983, and a Ph.D in Engineering Mechanics from Iowa State University, Ames, Iowa, USA in 1991. He has worked at Daewoo Heavy Industries, Ltd., Inchoen, Korea for 5 years from 1983, where he has been certified as ASNT Level III in RT, UT, MT and PT. He has worked at Chosun University, Gwangju, Korea as Assistant Professor for 5 years from 1993. Since 1998 he has been at Sungkyunkwan University, Suwon, Korea and is currently Professor of Mechanical Engineering.     

超声多普勒流速测量中存储容量的压缩方法

介绍了多普勒频率单片机测量时的数据处理方法，即线性地址变换法。在存储容量有效压缩的基础上，进一步分析了采样数据，用软件实现可控时标，保证了测量精度。     

Modeling,analysis and suppression of current harmonics of Langevin-type ultrasonic motors under high voltage

For achieving high speed and large thrust, Langevin-type ultrasonic motors (LTUM) are generally operated under high voltage. However, high voltage causes the current harmonics of piezoelectric material nonlinear phenomena, which will decrease the efficiency, the output force, and the accuracy of LTUMs. In this study, the nonlinearity of current harmonics of LTUM are described and analyzed by a novel nonlinear equivalent circuit model using Lagrange equations. Thereafter, based on a nonlinear tuning method, a specific driver circuit is suggested to suppress the current harmonics. Experimental results validate that the time response of the current is consistent with that of the model and furtherly demonstrate that the total harmonic current distortion decreases by 68% utilizing the proposed nonlinear tuning method under 500 Vpp.     

超声波无缝钢管探伤系统设计

超声波探伤是无损检测的一种常用方法,无缝钢管的应用十分广泛而大多数企业自动化程度不高,系统是针对圆形管件的自动化系统,具有自动化程度高,操作简便,实用性高等特点。详细阐释了其专用机床关键件的原理、PLC程序设计以及监控软件开发,对后续的非圆截面零件探伤也具备一定的借鉴意义。     

正弦波相位差的测量不确定度

本文介绍了用四参数正弦波最小二乘拟合法评价正弦波信号源相位差指标时的不确定度分析和评价过程。通过使用国军标GJB3756—1999“测量不确定度的表述及评定”中推荐的方法，讨论了影响评价结果不确定度的几个主要误差来源，包括采集速率的不确定度、通道间延迟时间差的不确定度、采集序列的谐波失真、采集序列的噪声及非谐波失真、采集序列中信号周期的抖动、软件拟合运算误差的影响等，给出了相位差测量结果的不确定度的分析与合成过程。结合一个实际评价例子，给出了相位差指标不确定度分析和评价结果，表明了该过程的正确性和切实可行性。该过程及结论可应用在对于计量标准进行正弦波相位差指标的不确定度分析上，也可用于估计正弦波相位差指标本身的不确定度。     

长环形驻波直线超声电机振子有限元分析

提出了一种长环形直线驻波超声电机振子,并对该超声电机振子进行了研究。利用有限元分析软件对振子的工作模态进行了分析,阐述了振子的工作原理。对支撑结构、影响振子振动模态固有频率的主要结构参数,进行了数值分析,确定了振子的结构形式。振子与支撑结构采用柔性铰链连接,利用第18阶正交的两个面内弯曲模态工作,实现了电机振子双接触面驱动、正反两个方向运动。证明了该类振子利用面内弯曲振动模态可以实现双面驱动、正反双向直线运动。为环型驻波直线超声电机的设计提供了理论参考。     

适用于精密复杂零件表面形状的干涉测量光学系统的光线追迹方法

在用激光干涉法测量精密复杂机械零件的表面形状误差时,需要用光学仿真的方法对干涉测量光学系统进行设计和误差分析.以研究中所用的光学系统为基本模型,提出均质媒质中的两个带有安装误差的任意界面曲面之间的光线追迹的一般方法,从任意一个3维界面曲面到平面、球面和圆柱面等若干个典型界面曲面之间的光线追迹方法,和由若干段均质媒质构成的光学系统中的光线追迹方法,并对测量对象面的成像形状的求解方法进行探讨,再以平面测量试验片和齿轮齿面为对象进行仿真计算和试验验证,仿真计算的结果和试验结果非常吻合,验证所提出的方法的正确性.     

非金属管道损伤的非线性超声导波延时检测定位方法

由于超声导波难以准确检测非金属管道的早期损伤,本文提出了一种非线性超声导波延时方法对非金属管道结构损伤进行测试和定位。基于非线性超声调制机理分析了非金属管道损伤状态,使用同侧非线性超声的混频信号激励方式并根据超声导波传播速度的差异产生激励信号延时,然后在管道损伤处实现混频信号的非线性调制。采用HHT(Hilbert-HuangTransformation)提取混频延时信号的瞬时特征量,并通过分析非线性分量延时分组进行损伤区域检测,实现了对非金属管道裂纹损伤的定位。PVC(Ployninylchloride)非金属管道实验显示,无损伤状态下延时信号分组的标准化基准值为0.518 8;单裂纹状态下延时信号分组标准值为0.593 7,损伤定位相对误差为3.277%;双裂纹损伤状态下的标准化瞬时平均幅值为0.580 1与0.607 3,损伤定位值绝对误差小于4mm。相对于利用小波包络分解的非线性延时定位检测法,实验得到的单裂纹损伤准确度提高了36.4%。结果表明该方法能够对非金属管道裂纹损伤准确定位,并能够检测早期多裂纹损伤。     

利用信号拼接提高调频连续波激光测距系统的分辨力

提出了一种对等频率间隔的采样信号进行拼接来提高调频连续波激光测距系统的测距分辨力的方法。研究了调频连续波激光测距的原理,设计搭建了基于一种双干涉系统的光纤调频连续波激光测距系统。利用辅助干涉系统产生的时钟信号对测量干涉系统的信号进行等光频间隔的采样,然后对采样信号进行拼接。使用LabVIEW设计了信号错误检测处理、采样和拼接的信号处理系统。利用该测距系统进行了实验验证,结果显示,将等光频间隔的采样信号进行拼接的方法可以突破激光器扫描范围的限制,减少光源非线性的影响,从而提高系统的测距分辨力。得到结果表明,在测量距离为8.7m时,该系统的测距分辨力可达70μm,30组测量结果的重复性标准差为35μm。     

利用数字全息干涉术测量电路板的连续弯曲形变

采用离轴菲涅耳数字全息干涉术实现了对电路板表面的连续弯曲形变测量。在电路板两端依次施加0.01mm至15mm位移载荷过程中,记录了1 501幅全息图。通过相邻两幅全息图数值重建的复振幅相位分布相减得到干涉相位差,根据相位差与离面位移的关系计算得到照明测量区域的离面位移,通过累加获得了施加1～15mm位移载荷时电路板表面的弯曲形变测量结果。由5块相同规格电路板上照明测量区域中同一电容中心点的离面位移,计算得到测量结果的A类不确定度不超过0.008mm,加载夹具引起的测量结果的B类不确定度为0.003 5mm,测量结果的合成不确定度不超过0.008 7mm。实验表明这种利用离轴菲涅耳数字全息干涉术测量物体大位移连续弯曲形变的方法具有良好的重复性和稳定性。