共查询到19条相似文献,搜索用时 109 毫秒
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介绍了一种在中,小范围内,采用激光定位,超声测距的新型测量仪器,该仪器以单片微处理器为核心,对不同的测量距离,采用不同频率的超声波,结合信号处理方法,从而实现0.6~14m范围内高精度实时测量目标距离,其测量相对误差优于1%。 相似文献
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主要阐述超声波传感器的测距原理,以及利用超声波距离模块、传感器和单片机一起构成超声波测距系统,并介绍该超声波测距系统的软件流程及超声波测距系统在智能汽车系中的多种应用。因超声波具有的独特的特性,使得超声波传感器越来越在生产生活中对保障行车安全,提高汽车智能化水平有重要意义。 相似文献
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目的为了解决卷筒纸印刷机高速运转时带来的纸带横向振动问题,设计一种高精度卷筒纸印刷机振动测试系统。方法把纸带的横向振动转化为距离测量,采用超声波测距的方法对纸带横向振动量进行测量,利用MSP430单片机自带的AD进行模数转换,把超声波探头输出距离的模拟量转化成数据量输出,显示在液晶屏上,并在PC端设计上位机软件,通过串口通信把测量的数据进行实时显示。结果通过对测试系统的实验,得到了实时的振动数据,经测试,该系统对振动纸张进行检测的精度达到了0.1 mm。结论通过超声波测距方法设计出一套卷筒纸印刷机纸带横向振动测试系统,减小了测量误差,提高了测量精度。 相似文献
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利用超声波测量距离是一种有效的非接触式测距方法,本文结合超声波精确测距的需要,分析了超声波测距的工作原理和系统构成,给出了软件控制流程,并在数据处理中采用了温度补偿修正,来有效提高超声波测距系统的精度。 相似文献
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基于AT89C51单片机的超声波测距系统设计 总被引:14,自引:0,他引:14
本文介绍一种基于AT189C51单片机的超声波测距系统,阐述了超声测距系统的构成、工作原理,给出了硬件电路框图和软件编程的设计方法。该系统具有硬件结构简单、工作可靠、测量误差小等特点。 相似文献
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介绍并设计一种基于单片机的超声测距系统。该系统以超声波的传播速度为确定条件.利用发射超声波与反射回波时间差来测量待测距离。概述超声波检测的基本原理。并且在介绍超声测距系统功能的基础上,提出系统的总体构成。 相似文献
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Peng Q Zhang LQ 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2011,58(1):122-133
Resolution of displacement measurements based on ultrasound pulse-echo techniques is limited by the center frequency of the transmitted wave, echo sampling rate, quantization errors, and electronic noises in the measurement system. We developed a new method utilizing the clutter signal in coded excitations to determine the displacement of an object or a desired region of an object with much improved resolution. The method includes transmitting a pair of Golay complementary sequences, receiving echoes from the object or a region of the object, compressing the pulse, eliminating the main lobe, and determining the object displacement between the two transmissions from the residual clutter signal around the main lobe of the compressed pulse. Results of computer simulations showed that the new method improved the resolution by several orders of magnitude and was more robust to noise than traditional pulse-echo methods. The new method was also evaluated using an experimental ultrasound system (10 MHz center frequency, 100 MHz sampling rate, and 8-bit sampling precision). A high precision in the displacement measurement was achieved with a measurement error of ?5.76 nm ±36.27 nm (mean ± standard deviation). The method has the potential to be applied in biomedical and industrial measurements of distance, displacement, and thickness. 相似文献
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Nabavizadeh A Urban MW Kinnick RR Fatemi M 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2012,59(4):752-765
We describe the theoretical principles of a new Doppler method, which uses the acoustic response of a moving object to a highly localized dynamic radiation force of the ultrasound field to calculate the velocity of the moving object according to Doppler frequency shift. This method, named vibro-acoustic Doppler (VAD), employs two ultrasound beams separated by a slight frequency difference, Δf, transmitting in an X-focal configuration. Both ultrasound beams experience a frequency shift because of the moving objects and their interaction at the joint focal zone produces an acoustic frequency shift occurring around the low-frequency (Δf) acoustic emission signal. The acoustic emission field resulting from the vibration of the moving object is detected and used to calculate its velocity. We report the formula that describes the relation between Doppler frequency shift of the emitted acoustic field and the velocity of the moving object. To verify the theory, we used a string phantom. We also tested our method by measuring fluid velocity in a tube. The results show that the error calculated for both string and fluid velocities is less than 9.1%. Our theory shows that in the worst case, the error is 0.54% for a 25° angle variation for the VAD method compared with an error of -82.6% for a 25° angle variation for a conventional continuous wave Doppler method. An advantage of this method is that, unlike conventional Doppler, it is not sensitive to angles between the ultrasound beams and direction of motion. 相似文献
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连续超声波束遇到振动物体表面会产生多普勒效应,反射超声波信号是受振动信号调制的非线性调相信号。对反射波信号求导获得调幅调频信号,再采用能量算子对称差分法,求取该调幅调频信号的瞬时幅值及瞬时频率。鉴于超声波反射回波信号存在幅值衰减现象,而超声波频率不易受外界干扰,故通过调幅调频信号的瞬时频率提取被测物体的振动速度,并由振动速度求导得到振动加速度。同时,从幅值及频率两个方面探讨振动测量范围。仿真及实验结果表明:基于能量算子的超声波测振信号解调方法能有效地提取振动信号,与传统的相位解调方法相比,具有更大的测量范围。 相似文献
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声波飞渡时间的准确测量是声学法测温中影响温度场测温准确性的主要因素。采用互相关分析法计算单一频率声波信号及宽带频率声波信号的声波飞渡时间,仿真结果表明宽带频率信号由于具有较强的抗噪能力在计算声波飞渡时间时不受声波信号周期、信号延时时间等因素的限制,可用于工程实践。同时采用频率为40kHz的正弦波超声波探测器在均匀温场条件下对超声波信号的衰减程度进行试验研究,试验结果表明40kHz的正弦波超声信号在不经过放大处理条件下,其可测温场的距离仅为160mm。 相似文献
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Three-dimensional Displacement Analysis by Windowed Phase-shifting Digital Holographic Interferometry 总被引:1,自引:0,他引:1
Abstract: Phase-shifting digital holography is a new method for measuring the displacement distribution on the surface of an object. The authors previously proposed a windowed phase-shifting digital holographic interferometry (windowed PSDHI). This method provides accurate displacement distributions by decreasing the effect of speckle patterns. In this study, the method is extended to analyse three-dimensional displacement components in a microscope. Three object laser beams in the optical system are used. Four phase-shifted holograms are recorded for each object laser beam. The complex amplitude of each reconstructed light at the object is calculated by the Fresnel diffraction integral of the complex amplitude of the hologram. The reconstructed distance is obtained at the point with the maximum of the standard deviation of the intensities of the object reconstructed with changing the reconstruction distance. The three phase-difference values between before and after deformation provide the three-dimensional displacement components. Theoretical treatment and experimental results of three-dimensional displacement measurement using this method are shown. 相似文献
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Aspects of the application of the method of direct correlation processing of speckle fields for measurement of the movement
of diffuse objects in the case of “boiling” speckle fields are investigated. It is shown that this method may be used for
measurements of the magnitude and direction of motion of diffuse objects in a plane parallel to the observation plane. An
error in the determination of the movement of the object not greater than ±5 μm is obtained within a measurement region in
which the distance from the object to all reference points does not exceed the correlation radius. 相似文献
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There are two methods applied for three-dimensional digital image correlation method to measure three-dimensional displacement. One is to measure the spatial coordinates of measuring points by analyzing the images. Then, the displacement vectors of these points can be calculated using the spatial coordinates of these points obtained at different stages. The other is to calibrate the parameters for individual measuring points locally. Then, the local displacements of these points can be measured directly. This study proposes a simple local three-dimensional displacement measurement method. Without any complicated distortion correction processes, this method can be used to measure small displacement in the three-dimensional space through a simple calibration process. A laboratory experiment and field experiment are carried out to prove the accuracy of this proposed method. Laboratory test errors of one-dimensional experiment are similar to the accuracy of the XYZ table; the error in Z-direction is only 0.0025% of the object distance. The measurement error of laboratory test is about 0.0033% of the object distance for local three-dimensional displacement measurement test. Test and analysis results of field test display that in-plane displacement error is only 0.12 mm, and the out-of-plane error is 1.1 mm for 20 m × 30 m measuring range. The out-of-plane error is only about 10 PPM of the object distance. These test and analysis results show that this proposed method can achieve very high accuracy under small displacement for both of laboratory and field tests. 相似文献