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Signal Processing Using a circular sensor array to Measure the Torsional Angle of a Bolted Joint

sensorS 2024年第9期24卷 2719页

作者： Schuethe, Thorben Riemschneider, Karl-Ragmar Meyer-Eschenbach, Andreas Hamburg Univ Appl Sci Fac Engn & Comp Sci D-20099 Hamburg Germany

This study presents a new approach to determining the preload force of bolted joints. The concept involves measuring the torsional angle without contact. For this purpose, we present a circular magnetic sensor array integrated into the torque wrench. The torsional angle in bolted joints depends on the dimensions of the screw and the materials used and is typically less than four degrees. For this reason, one requirement is a high angular resolution so that a continuous recording of the torsion angle is feasible during the assembly process. This can be achieved using the circular sensor array and adapted signal processing methods. Two signal processing approaches are utilized. First, the direct method uses the discrete Fourier transformation to calculate the rotation angle from the signal phase. This approach is robust to signal distortion and does not depend on signal amplitude. Second, the method with a learning phase employs Gaussian process regression to minimize the angle error. In an experiment, both approaches were applied within a test bench and showed promising results. The direct method demonstrated a very good angular resolution without training and calibration. For mobile and less-complex applications where a reference system is unavailable, the direct method is preferable. However, in complex measurement systems where reference systems can be utilized initially, significant enhancements to an excellent resolution can be achieved through prior training.

关键词： magnetic angle measurement magnetic resolver circular sensor array torsion measurement bolted joint torsional stress bolt preload monitoring Gaussian process regression

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Imaging of Multiple Cracks in Thin Plates using circular sensor array Based on Lamb Waves

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ACOUSTICAL PHYSICS 2023年第4期69卷 588-598页

作者： Wang, Zijian Gao, Zihang Shi, Binkai Chen, Binghong Southeast Univ Sch Civil Engn Minist Educ Key Lab C&PC Struct Nanjing 211102 Peoples R China Rocket Force Univ Engn Dept Basic Educ Xian 710025 Peoples R China Hohai Univ Coll Water Conservancy & Hydropower Engn Nanjing 210098 Peoples R China

Crack imaging is attractive in the community of nondestructive testing and structural health monitoring of plate-like structures. However, most existing research focuses on the imaging of single crack, while limited work has been reported for the imaging of multiple cracks. To this end, the application of the Lamb wave-based technique is presented in this paper to image the multiple cracks. The antisymmetric mode (A0) of Lamb wave propagation in the thin plate is simulated using the numerical finite element method, and a circular piezoelectric sensor array is considered to capture the Lamb wave signals. The damage index taking into account the attenuation of the reflected signal amplitude is proposed using the reflection signals from the cracks, and the Hilbert transform is used to extract the information of damage. The damage scanning map is constructed to show the damage location in the plate. The proposed damage identification algorithm based on Lamb wave propagation is also used to detect two cracks in the thin plates. The consideration of wave attenuation improves the identification of multiple cracks. The proposed damage identification algorithm using a phased piezoelectric sensor array shows its potential to locate the cracks in thin plates.

关键词： Lamb waves crack identification multi-cracks damage scanning map circular sensor array

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Localization of CO₂ Leakage from a circular Hole on a Flat-Surface Structure Using a circular Acoustic Emission sensor array

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sensorS 2016年第11期16卷 1951-1951页

作者： Cui, Xiwang Yan, Yong Guo, Miao Han, Xiaojuan Hu, Yonghui North China Elect Power Univ Sch Control & Comp Engn Beijing 102206 Peoples R China Univ Kent Sch Engn & Digital Arts Canterbury CT2 7NT Kent England

Leak localization is essential for the safety and maintenance of storage vessels. This study proposes a novel circular acoustic emission sensor array to realize the continuous CO2 leak localization from a circular hole on the surface of a large storage vessel in a carbon capture and storage system. Advantages of the proposed array are analyzed and compared with the common sparse arrays. Experiments were carried out on a laboratory-scale stainless steel plate and leak signals were obtained from a circular hole in the center of this flat-surface structure. In order to reduce the influence of the ambient noise and dispersion of the acoustic wave on the localization accuracy, ensemble empirical mode decomposition is deployed to extract the useful leak signal. The time differences between the signals from the adjacent sensors in the array are calculated through correlation signal processing before estimating the corresponding distance differences between the sensors. A hyperbolic positioning algorithm is used to identify the location of the circular leak hole. Results show that the circular sensor array has very good directivity toward the circular leak hole. Furthermore, an optimized method is proposed by changing the position of the circular sensor array on the flat-surface structure or adding another circular sensor array to identify the direction of the circular leak hole. Experiential results obtained on a 100 cm x 100 cm stainless steel plate demonstrate that the full-scale error in the leak localization is within 0.6%.

关键词： CO2 leakage leak localization acoustic emission circular sensor array

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Current Measurement With 3-D Coreless TMR sensor array for Inclined Conductor

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IEEE sensorS JOURNAL 2019年第16期19卷 6684-6690页

作者： Zhang, Huaiqing Li, Feifan Guo, Huan Yang, Zhiyuan Yu, Nian Chongqing Univ State Key Lab Transmiss Equipment & Syst Safety & Chongqing 400044 Peoples R China

Magnetic sensor arrays have been widely used in current measurement, due to their advantages of small size, low power consumption, high sensitivity, wide bandwidth, and large dynamic range. However, they all assume that the conductor is perpendicular to the plane of the sensor array and the error introduced by un-perpendicularity has not been eliminated until now. In this paper, a 3-D tunnel magnetoresistance (TMR) sensor array scheme with its correction algorithm for eccentric, inclined current-carrying conductor is proposed. The simulation comparison of the relative error caused by the inclined angle between 1-D, 2-D, and 3-D TMR sensor arrays is performed, where the maximum errors are 25%, 20.5%, and 139%. It is obvious that the correction algorithm of 3-D TMR sensor array can significantly improve the accuracy. Four 3-D TMR sensors are used in the experimental prototype to verify the accuracy and reliability of the correction algorithm.

关键词： Coreless current transducer TMR sensor un-perpendicularity circular sensor array correction algorithm

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Robust Superdirective Beamforming With Sidelobe Constraints for circular sensor arrays via Oversteering

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IEEE sensorS JOURNAL 2023年第18期23卷 21698-21708页

作者： Wang, Yong Li, Shouci Yang, Long Yang, Yixin Northwestern Polytech Univ Sch Marine Sci & Technol Xian 710072 Shaanxi Peoples R China

This article proposes a beamforming method via oversteering for circular sensor arrays, which can synthesize robust superdirective beampatterns with constrained sidelobes. Because the optimal beampattern can be expressed as the sum of finite eigenbeams with different directivities and robustness levels, adjusting the maximum order can achieve beampatterns with a desired robustness level. The sidelobes of these robust beampatterns in azimuth at low frequencies are found to decrease when the optimal weighting vector is oversteered in elevation;thus, robust superdirective beampatterns with constrained sidelobes and robustness can be synthesized by combining the order-adjusting and oversteering techniques;moreover, it is found that only the oversteering amount is required to synthesize desired superdirective beampatterns when robustness and sidelobe constraints are given beforehand. The relationship between the oversteering amount and the frequency can be approximately expressed using a simple neutral network, according to which desired broadband superdirective beampatterns can be readily achieved. Simulations and experimental results show that the performance of the proposed method is like that of the optimization-based method but using a simplified implementation approach rather than a complex numerical algorithm.

关键词： Beamforming circular sensor array sidelobe constraint superdirectivity

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Theoretical and Practical Solutions for High-Order Superdirectivity of circular sensor arrays

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IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS 2013年第1期60卷 203-209页

作者： Ma, Yuanliang Yang, Yixin He, Zhengyao Yang, Kunde Sun, Chao Wang, Yingmin Northwestern Polytech Univ Inst Acoust Engn Xian 710072 Peoples R China

An analytical and closed-form optimal solution expressed in elementary functions for superdirectivity of a circular sensor array is proposed in this paper. By utilizing the circulant property of the data covariance matrix for circular sensor arrays, such solutions are derived to accurately calculate the optimal beamforming vector, optimal beam pattern, corresponding directivity factor, and eigenbeams. Based on these solutions, it is proved that such array possesses several important properties which facilitate an eigenbeam decomposition and synthesis approach for practical implementations. Experiments conducted result in superdirective beams which contain zeroth- to fifth-and sixth-order eigenbeams. As a typical result, the superdirective beam which contains zeroth- to fifth-order eigenbeams has a 28 degrees beamwidth and a 12-dB directivity index with a small circular array radius of 0.267 wavelength.

关键词： circular sensor array high-order superdirectivity optimal beamforming sonar signal processing

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A Flexible Method for Designing Frequency-Invariant Beamformers With circular sensor arrays

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IEEE ACCESS 2018年 6卷 57073-57084页

作者： Wang, Yong Yang, Yixin Northwestern Polytech Univ Sch Marine Sci & Technol Xian 710072 Shaanxi Peoples R China

This paper proposes a flexible method for designing frequency-invariant (FI) beamformers, which is suitable for circular arrays mounted on acoustically transparent and infinite rigid cylinders. The closed-form weighting vectors at each frequency are accurately derived by approximating to a general complex-weighted desired beampattern from the minimum mean square error perspective. It is found that these obtained weighting vectors are all closed-form functions of the desired complex weighting vectors. A multiple-constraint optimization problem is formulated, and its solution gives the optimal desired weighting vector subject to different constraints. Then, the weighting vectors at other frequencies can be straightforwardly computed based on the previously derived analytical functions. The proposed method provides flexible schemes to design different FI beamformers for circular sensor arrays. The good performance of the proposed method is demonstrated using simulations and experimental results.

关键词： Frequency-invariant beamforming circular sensor array multi-constraint optimization

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Robust Superdirective Frequency-Invariant Beamforming for circular sensor arrays

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IEEE SIGNAL PROCESSING LETTERS 2017年第8期24卷 1193-1197页

作者： Wang, Yong Yang, Yixin He, Zhengyao Ma, Yuanliang Li, Bing Xi An Jiao Tong Univ Sch Mech Engn Xian 710049 Peoples R China Northwestern Polytech Univ Sch Marine Sci & Technol Xian 710072 Peoples R China

This letter proposes a robust superdirective frequency-invariant beamforming method for circular sensor arrays. First, the beampattern is accurately transformed into an equivalent form using the property of circular arrays, and the expressions of directivity factor and white noise gain are correspondingly modified. Second, a closed-form weighting vector is accurately derived based on the minimum mean square error approximation to a desired superdirective beampattern that is expressed in a general form. When the number of elements is sufficiently large, the weighting vector can be further simplified, and the white noise gain is also modified to a concise form that is found to be an increasing function of the number of elements in the low-frequency range. Simulations and experimental results show that this method can provide a robust superdirective frequencyinvariant beampattern over a wide frequency band given a suitable number of elements, and it can be readily applied to process broadband signals in practice using small circular sensor arrays.

关键词： circular sensor array frequency-invariance robustness superdirective beamforming

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Localization of Continuous Gas Leaks from a Flat-Surface Structure Using an Acoustic Emission sensor array

Localization of Continuous Gas Leaks from a Flat-Surface Str...

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IEEE International Instrumentation and Measurement Technology Conference (I2MTC)

作者： Cui, Xiwang Yan, Yong Guo, Miao Hu, Yonghui Han, Xiaojuan North China Elect Power Univ Sch Control & Comp Engn Beijing 102206 Peoples R China Univ Kent Sch Engn & Digital Arts Canterbury CT2 7NZ Kent England

ISBN: (纸本)9781467392204

Leak localization is of great importance for pressurized vessels for reasons of safety and maintenance. This paper presents an experimental study using an Acoustic Emission sensor array coupled with a hyperbolic positioning algorithm for continuous leak localization. The study aims to detect continuous CO2 leak from an isotropic flat-surface structure on a pressurized vessel in the Carbon Capture and Storage system. The proposed approach consists of four main stages. In the first stage, empirical mode decomposition is deployed to extract the useful signal from the noise. The second step is concerned with the estimation of the time differences of the sensor array in conjunction with correlation signal processing. The third stage estimates the distance difference between the sensing elements from the measured time differences and wave speed. Finally, a hyperbolic positioning algorithm is used to locate the leak source on the flat-surface structure. Results obtained from experiments on a 100 cm. 100 cm stainless plate demonstrate that the mean full-scale error in the leak localization is 4.9%.

关键词： continuous leak localization circular sensor array acoustic emission hyperbolic positioning cross correlation

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Surface Crack Size Estimation Based on Quantification and Decoupling of Magnetic Flux Leakage (MFL) Signals of circular array sensors

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IEEE sensorS JOURNAL 2024年第10期24卷 16752-16762页

作者： Gong, Wendong Akbar, Muhammad Firdaus Jawad, Ghassan Nihad Zhang, Fengqin Univ Sains Malaysia Sch Elect & Elect Engn Nibong Tebal 14300 Penang Malaysia Univ Baghdad Dept Elect & Commun Engn Baghdad 10071 Iraq Shandong Polytech Sch Urban Rail Jinan 250104 Peoples R China

It is of great importance to improve the detection accuracy of initial fatigue cracks on rail top surfaces to provide an early warning of rail damage. However, it is a challenge to accurately quantify such cracks due to their usual narrow width and various angular variations. This article proposes a quantification method for crack surface dimensions (i.e., angle, width, and length) by decoupling the magnetic flux leakage (MFL) resulting from circular sensor arrays. First, the correlation between the distribution characteristics of the MFL signals and the crack surface size is analyzed by finite element simulation to determine the quantification sequence of the surface crack dimensions. Next, the crack angle is quantified based on the temporal relationship of the MFL circular sensor array signals. Then, the gradient edge of the magnetic leakage flux density modulus is used to quantify the width of the surface crack. Finally, the crack length is quantified by utilizing the number of sensors that detect a valid MFL signal in the circular array. Experimental results show that the maximum quantification accuracy for the crack's angle, width, and length are about 95.0%, 91.2%, and 88.4%, respectively. This indicates that the proposed method can highly improve the quantification accuracy of crack surface dimensions.

关键词： Rails Surface cracks sensor arrays Magnetic sensors sensor phenomena and characterization Magnetic flux leakage Finite element analysis circular sensor array magnetic flux leakage (MFL) detection rail cracks signal features

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