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1.
《中国测试》2020,(2):96-102
为对声源进行精确定位,该文设计一种基于广义互相关法时延估计的四元十字麦克风阵的声源定位算法。推导目标声源的方位角、俯仰角以及距离的计算公式,搭建实验和仿真平台,将该算法运用于平面声源定位中进行验证。采用LabVIEW软件进行算法的三维空间仿真实验,通过对各麦克风采集信号进行相关分析和处理,实现声源的定位,测试该系统在实际应用中的性能。二维平面定位实验结果声源距离的误差范围在0.01~0.02 m之间,距离偏差百分比误差范围在5.5%之内,仿真结果坐标与实际声源坐标的结果误差范围在10%~15%,该系统的坐标偏差误差在7%之内,距离偏差百分比误差范围在4%之内。搭建实验平台进行三维空间定位测试,实验结论表明,距离偏差百分比低于9%,表明该系统对声源定位速度较快,误差在合理范围内,精度理想,能够比较准确地对声源进行定位。 相似文献
2.
针对飞行器在飞行试验后回收效率低的问题,设计一种指示飞行器落点坐标的信标机。该型信标机由定位模块、短报文发送模块、电源模块、信息处理模块等组成。其可在下落过程中不断获取实时定位信息,通过数学方法计算预测落点的坐标;再利用北斗系统的短报文通信功能将预测的落点坐标发送回地面,落地后如果信标机能正常工作,则会按照一定频度持续发送实时落点信息。依照上述理论制作信标机并通过多次模拟实验进行验证。结果表明:获取到的预测坐标与实际落点坐标在经、纬度方向上的误差在±20 m以内,海拔高度方向上的误差在±5 m以内,搜索人员可以很快地找到目标设备,提高回收效率。 相似文献
3.
《纳米技术与精密工程》2017,(6)
为了快速准确定位气体泄漏,提出了一种基于超声导波的泄漏定位方法.使用超声传感器阵列采集泄漏产生的超声导波信号,通过改进的波束形成方法估计泄漏方向,再利用三角定位法通过多个传感器阵列确定泄漏位置.进行泄漏定位实验,通过实验确定了定位计算时窄带滤波的带宽为20 k Hz.实验表明,在长宽为1 m×1 m的实验平板上,该方法对1~2 mm孔径的漏孔的平均定位误差小于10 mm,实现了对气体泄漏声源的准确定位. 相似文献
4.
目的为了实现码垛机器人的实时快速控制,设计一种模块化示教的码垛机器人控制系统。方法以1802芯片为核心开发嵌入式模块示教系统,以QT为工具开发上位机模块示教系统,使用示教系统可以快速设定码垛机器人的路线和精度,通过wifi或串口模块把示教信号传输到码垛机器人控制系统中,控制系统利用高速脉冲驱动电路和闭环控制定位程序,使码垛机器人按照示教信息快速精准地搬运货物,点对点搬运实验表明,系统定位精度可以达到0.3 mm,旋转误差在0.1°内。结果机器人水平定位的最大相对误差为0.45%,旋转角度的最大误差为0.83%。结论实验证明,码垛机器人控制系统可以根据用户需求快速完成搬运。 相似文献
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针对经典波束形成算法不具备实时性、占用存储空间大、计算速度慢等缺点,提出了基于卡尔曼滤波器的算法。这种算法将信号处理领域中现有的卡尔曼滤波器理论与阵列信号处理过程相结合,在频域内对声学阵列所采集到的数据进行迭代处理,不仅能够及时发现风洞测量中存在的各种问题,而且可以实时消除由测量环境所引起的各种误差。仿真结果表明,这种算法比经典波束形成算法收敛速度更快,不仅成像效果很好,而且能够对低速运动声源进行定位。此算法具备实时性,为风洞声源的实时定位提供了重要的算法选择。 相似文献
7.
《中国测试》2020,(1):140-146
针对目前EBS桥模块性能检测领域的技术空白,依据QC/T35-2015《汽车与挂车气压控制装置台架试验方法》和企业测试要求,研发一套针对EBS桥模块的专用在线检测装置,能够完成EBS桥模块的常规静特性、常规响应特性、电控响应特性、阶梯升降压特性的在线检测。基于研华高精度数据采集卡设计数据采集模块,采集频率为1 000 Hz;采用电气比例阀、调压阀实现输入气压的精准控制,检测系统气压测量范围为0~1.6 MPa,气压测量精度为±0.1%;上位机部分采用LabVIEW编程,实现检测流程的自动化控制和测试数据管理功能。对测试系统进行大量重复性实验,进行不确定度分析,得出响应时间的最大不确定度为0.379 5 ms,检测气压的最大合成不确定度为1.608 9 kPa,该检测系统性能稳定,满足企业测试要求。 相似文献
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在室内噪声控制中,由于噪声源数量多且室内声场复杂,造成噪声源评价困难。提出一种室内噪声源评价方法:首先根据声源可能存在的位置进行区域划分,然后在各区域内利用波束形成方法进行声源定位,找到该区域A计权声压级最大的噪声源。再将各主要声源对噪声评价位置进行传递路径分析,计算各声源对该位置的贡献量。最后通过传递路径分析合成的噪声与该位置实际所测噪声的误差分析判断主要声源识别的有效性。仿真研究表明该方法能有效降低室内混响对声源定位的影响,减小传递路径方法的工作量,便于找到对评价位置影响最大的主噪声源。 相似文献
10.
苏州-南通气体绝缘金属封闭式输电线路(Gas-Insulated metal-enclosed transmission Line,GIL)综合管廊工程是目前世界上电压等级最高、输送容量最大、技术水平最高的超长距离GIL创新工程。通过分析管廊内部结构,建立了其物理模型,根据声学理论,结合管廊布置方式提出两种计算模型,采用有限元方法对苏通GIL综合管廊的声场分布进行计算,并能为管廊内的故障声波定位提供参考。研究结果表明:对于非均匀声源,管廊的平面波截止频率在15 Hz附近。若声源频率低于15 Hz,声波在传播过程中快速转化为一维平面波,可采用"到达时间差法"(Time Difference of Arrival,TDOA)进行定位;如果声源频率高于15 Hz,则需对声波信号做进一步的时域和频域分析以确定适合的定位算法。 相似文献
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S I Bondarenko A V Lukashenko A A Shablo E N Tilchenko Yu K Neimirok 《Bulletin of Materials Science》1991,14(4):1115-1118
The results of the study of dc interferometers and SQUIDS from the thick-film YBa1·5Ca0·5Cu3O7\t-\gd ceramics are presented here. It is shown that under the influence of high-density currents through the film constriction
the differential resistance of interferometers thus formed increases by 2–3 orders of magnitude and the voltage-field characteristics
become more regular. The frequency dependence of intrinsic noise in dc SQUIDs based on thick-film interferometers is investigated.
It is demonstrated that in the white noise frequency region (1–10 Hz) the energy sensitivity is withinδɛ
n
=10−28 to 10−29 J/Hz. 相似文献
13.
Sharma H. Kumari Kiran Singh L. S. Choudhary R. N. P. 《Bulletin of Materials Science》2002,25(2):133-136
The polycrystalline samples of Ca4Bi2Ti4Nb6O30 (herein designated CBTN) were synthesized by the conventional ceramic method. Preliminary X-ray structural study of the compound
showed the formation of a single phase solid solution having orthorhombic structure in the paraelectric phase. Measurements
of the dielectric constant (ε) and dielectric loss (tan δ) as a function of temperature (−180–200°C) at 1 kHz and 10 kHz and
also as a function of frequency (102 Hz to 104 Hz) at five different temperatures [−180°C, −40°C, − 10°C 26°C (room temperature) and 75°C] have shown a dielectric anomaly
and a phase transition at − 13 ±1°C in CBTN. 相似文献
14.
针对交流发电机气动噪声声源组成的复杂性和不同旋转方向对交流发电机气动噪声影响问题,基于Lighthill声学理论,采用LES(Large Eddy Simulation,大涡模拟)和FW-H(Ffowcs Williams-Hawking方程)声学模型对交流发电机气动噪声进行数值模拟。研究结果表明:LES在交流发电机噪声数值预测方面其主要阶次及幅值与试验对比有很好的一致性;前后扇叶为该型交流发电机的主要气动噪声声源;第6、8、10、12和18等阶次为交流发电机气动噪声主要影响阶次,且主要能量集中在1 120 Hz~5 600 Hz频率范围内;反方向运行工况的交流发电机总声压级较正方向运行时大9.17 d B,质量流量较正方向运行的小62.87 g/s。研究成果可为车用交流发电机气动噪声性能的提高提供切实可行的参考。 相似文献
15.
Flexible piezo- and pyroelectric composite was made in the thin film form by spin coating. Lead Zirconate Titanate (PZT) ceramic
powder was dispersed in a castor oil-based polyurethane (PU) matrix, providing a composite with 0–3 connectivity. The dielectric
data, measured over a wide range of frequency (10–5 Hz to 105 Hz), shows a loss peak around 100 Hz related with impurities in the polymer matrix. There is also an evidence of a peak in
the range 10–4 Hz, possibly originating from the glass transition temperature Tg of the polymer. The pyroelectric coefficient at 343 K is 7.0×10–5 C·m–2·K–1 which is higher than that of β-PVDF (1×10–5 C·m–2·K–1).
Electronic Publication 相似文献
16.
Small angle magnetization rotation of Metglas 2826MB, 2605SC and 2605CO and Vitrovac 4040 ribbons under both tensile and compressive
stress is investigated. It appears that there is no significant difference between the saturation magnetostriction of a ribbon
when measured in tension or compression. Values determined forλ
s are 2826MB: 12.5±0.7×10−6; 2605SC: 30±2×10−6; 2605CO: 37±2×10−6 and 4040: 10.4±0.7×10−6. 相似文献
17.
V. B. Efimov A. N. Ganshin P. V. E. McClintock G. V. Kolmakov L. P. Mezhov-Deglin 《Journal of Low Temperature Physics》2007,148(3-4):251-255
The preliminary results of an investigation of nonlinear second sound waves in a high quality resonator filled with superfluid
4He are presented and discussed. It is found that, for a sufficiently strong periodic driving force, a cascade of second sound
waves is formed at multiple harmonics of the driving frequency over the extremely wide frequency range 1–100 kHz. It can be
described by a power law A
ω
=const.×ω
−m
, where the scaling index m≈1. These observation can be attributed to the formation of a Kolmogorov-like turbulent cascade in the system of second sound
waves, accompanied by directed energy flux through the frequency scales. It manifests itself as a limiting of the amplitude
of a standing wave, a distortion of the shape of the initially harmonic waves, and a reduction of the effective quality factor
Q of the resonator. 相似文献
18.
The speed of sound in gaseous refrigerants R-134a and R-507a is measured by the method of ultrasonic interferometer in a temperature
interval from 293 to 373 K and pressure values from 0.01 to 0.5–2.9 MPa. The errors in measurement of the temperature, pressure,
and speed of sound are ±20 mK, ±4 kPa, and ±(0.1–0.2)%, respectively. On the basis of the data obtained, the temperature dependence
of the idealgas heat capacity is calculated. The results obtained are compared with calculation of speed of sound from the
fundamental state equation for Helmholtz free energy. 相似文献
19.
G. E. Snopatin V. G. Plotnichenko S. A. Volkov V. V. Dorofeev E. M. Dianov M. F. Churbanov 《Inorganic Materials》2010,46(8):914-917
The absorption spectra of (TeO2)0.78(WO3)0.22 glasses containing 0.01–1.0 wt % NiO have been measured at wavelengths from 450 to 2700 nm, and the spectral dependence of
the extinction coefficient of Ni2+ in the glasses has been obtained. In the absorption bands centered at 810 and 1320 nm, the extinction coefficient is 20.2
± 0.8 cm−1 (870 ± 35 dB/(km ppmw)). According to the spectral range of its absorption and its extinction coefficient, nickel is a strongly
absorbing impurity in tellurite glasses. The present results can be used to formulate sound nickel concentration limits in
tellurite glasses for fiber-optic applications. 相似文献