- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Automatic signal quality check and equipment condition surveillance based on trivalent logic diagnosis theory
摘要： In the field of fault diagnosis, inadequate signals measured for equipment condition monitoring may cause incorrect diagnostic results and reduce the accuracy and reliability of the equipment diagnosis system. This paper proposes a method of signal quality check and equipment condition surveillance based on trivalent logic theory, signal histogram analysis and principal component analysis (PCA), in order to automatically evaluate the quality of measured signals to ensure that the signals are real and valid for the condition diagnosis of equipment, and automatically judge the equipment state for condition surveillance. The novelty of this paper are summarized as: (1) Trivalent logic has been expanded appropriately into the trivalent logic diagnosis theory, so that it can be applied to verify the signal quality in the acquisition process for fault diagnosis and equipment condition surveillance; (2) In order to directly and effectively extract features of a signal following any probability density distribution, the histograms of the signal measured for equipment condition diagnosis is used to substitute time domain symptom parameters which have been generally used in equipment diagnosis technology; (3) PCA is used to integrate the histograms to realize signal quality check and equipment condition surveillance on the basis of the trivalent logic diagnosis theory. By the method proposed in this paper, the moment when the signal for equipment condition diagnosis is relatively stable can be found, and the unfavorable signal can be avoided for ensuring the accuracy and reliability of the equipment condition diagnosis. Simulation signals and real signals measured in various conditions from a blower are respectively used to verify the effectiveness of the proposed method.
关键词： Condition monitoring,Fault diagnosis,Measurement errors,Histograms,Vibration measurement
更新于2025-09-23 15:23:52
-
[IEEE 2019 IEEE 1st International Conference on Energy, Systems and Information Processing (ICESIP) - Chennai, India (2019.7.4-2019.7.6)] 2019 IEEE 1st International Conference on Energy, Systems and Information Processing (ICESIP) - PV fed LLC-LC Multi-resonant Converter based LED Driver
摘要： In many circumstances, the conventional ultrasonic liquid-level detection presents the unreliable estimations due to the dynamically changed liquid level. In addition, there are circumstances where the level change involves not only the fluctuation but also the rise or fall of liquid level. To improve the measuring accuracy of liquid level using the ultrasonic method in dynamically changed level case, an attractive ultrasonic method, named the liquid-level detection based on the multiple-input multiple-output ultrasonic transducer array, is proposed in this paper. This method is different from the early ultrasonic liquid-level detections, including those that utilize transducer array. Based on the virtual element technology, the method employs the multitransducer array to achieve the reduction of system complexity and cost, and then applies the synthetic aperture technology to realize rapid samples of liquid level. Besides, one adaptive searching scheme of focused position in beamforming of synthetic aperture in each scanning direction is optimized to get the high precise samples of liquid level. The proposed method is verified by simulation and a real system, and compared with the conventional single-channel approach. We still proposed a simulation method of ultrasonic echo signal from liquid level based on the boundary-layer theory and the ultrasonic scattering theory. The simulated and actual measurement results demonstrate that the proposed method is obviously superior to the conventional approach. Meanwhile, the factors influencing on the proposed method are investigated by simulation also. The investigations reveal that the focus position in beamforming, the SNR of echo signal, and the wave size of liquid level have impact on the suggested method. However, it is indicated that the good performance of the proposed method remains, provided that the focus in beamforming is properly set in every scanning direction and the noise of echo signal is effectively controlled.
关键词： level measurement,multiple-input multiple-output (MIMO) systems,Acoustics,transducers,measurement errors,arrays
更新于2025-09-19 17:13:59
-
[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Study of optoelectronic properties of thin MoO <sub/>x</sub> films for application in silicon solar cells
摘要： In many circumstances, the conventional ultrasonic liquid-level detection presents the unreliable estimations due to the dynamically changed liquid level. In addition, there are circumstances where the level change involves not only the fluctuation but also the rise or fall of liquid level. To improve the measuring accuracy of liquid level using the ultrasonic method in dynamically changed level case, an attractive ultrasonic method, named the liquid-level detection based on the multiple-input multiple-output ultrasonic transducer array, is proposed in this paper. This method is different from the early ultrasonic liquid-level detections, including those that utilize transducer array. Based on the virtual element technology, the method employs the multitransducer array to achieve the reduction of system complexity and cost, and then applies the synthetic aperture technology to realize rapid samples of liquid level. Besides, one adaptive searching scheme of focused position in beamforming of synthetic aperture in each scanning direction is optimized to get the high precise samples of liquid level. The proposed method is verified by simulation and a real system, and compared with the conventional single-channel approach. We still proposed a simulation method of ultrasonic echo signal from liquid level based on the boundary-layer theory and the ultrasonic scattering theory. The simulated and actual measurement results demonstrate that the proposed method is obviously superior to the conventional approach. Meanwhile, the factors influencing on the proposed method are investigated by simulation also. The investigations reveal that the focus position in beamforming, the SNR of echo signal, and the wave size of liquid level have impact on the suggested method. However, it is indicated that the good performance of the proposed method remains, provided that the focus in beamforming is properly set in every scanning direction and the noise of echo signal is effectively controlled.
关键词： level measurement,measurement errors,arrays,multiple-input multiple-output (MIMO) systems,transducers,Acoustics
更新于2025-09-19 17:13:59
-
Comparative Evaluation of the Accuracy and Robustness of Various Information Processing Algorithms from Tripled Measuring Channels
摘要： Using the example of a three-channel system for measuring the level of filling of tanks of launch vehicles, we perform a comparative assessment of the accuracy and robustness of various algorithms for processing measurement information received from three measuring channels of the same type. We consider various processing algorithms of three equal-precision measurements: finding the arithmetic mean of three equal-precision measurements and a majority choice of three equal-precision measurements. For these algorithms, the probability density function of the measurement errors and confidence limits of the measurement error are found using the assumption of uniform or normal laws of the error distribution of three equally accurate measurements. A generalized algorithm for processing redundant information is proposed. The essence of the generalized algorithm is the addition of three equally accurate measurements taking into account individual weighting factors. Weight coefficients are selected based on the values of three equally accurate measurements: the minimum and maximum values are assigned the same weighting coefficient, and the median is assigned a coefficient which normalizes the sum of the three weighting factors to one. For a generalized algorithm by means of simulation modeling, the confidence limits of the measurement error are determined depending on the selected weighting factors. The robustness of the considered processing algorithms is evaluated for three equally accurate measurements performed on three measuring channels identical in design, with a random perturbation applied to one of the channels. Recommendations on the selection of weights for three equal measurements are given. For the fuel level measurement system under consideration, it is justified to use an algorithm for processing measurement information based on a majority choice of three equally accurate measurements.
关键词： algorithms for processing redundant measurement information,probability density distribution of measurement errors,robustness,weight coefficients,confidence limits of measurement error,Monte Carlo simulation
更新于2025-09-12 10:27:22
-
[IEEE 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Paris, France (2018.7.8-2018.7.13)] 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Evaluating the Uncertainty of Self-Calibrating VNA Procedures
摘要： Some important vector network analyzer (VNA) calibration procedures, such as thru-re?ect-line (TRL), are not amenable to uncertainty analysis by conventional methods, because the calibration equations do not refer to the standards used. Nevertheless, by relating small changes in standard S-parameter values to corresponding changes in VNA response, sensitivity coef?cients for the error coef?cients obtained by calibration can be evaluated indirectly. The approach is easily implemented with uncertain-number software.
关键词： scattering parameters,measurement uncertainty,Measurement errors
更新于2025-09-10 09:29:36
-
New W-band Scattering Measurement System: Proof of Concept and Results for 2D Objects
摘要： The paper deals with a detailed study of an original system dedicated to scattering measurements of millimeter waves in the W-band. The system’s main innovations lie in its high-precision swivel arm, semi-anechoic environment, flexibility for positioning the object on the measurement tower, as well as the post-processing developed to correct measurement errors. We use canonical objects, i.e. cylinders, for tests and evaluate measurement errors and system performance by comparisons with the theoretical scattered field, which has an analytical expression. For the sake of generality, we work with both VV and HH-polarizations. We propose a complete workflow that performs noise suppression and positioning error correction, relying on two quantities: 1) the cut-off frequency of a low pass filter and 2) the pre-determination of the position of the device under test (DUT). The originality of our approach is that both quantities are fully-defined by the measurement data without a priori knowledge of the DUT. Since the different steps of the workflow are generic, it can easily be transposed to any scattering measurement system. Finally, once corrected, measurements at 75, 95, and 110 GHz exhibit signal-to-noise ratios (SNR) of close to 15 dB for dielectric cylinders and up to 25 dB for metallic ones. To the best of our knowledge, this is the first time that such values have been exhibited in the W-band.
关键词： Millimeter wave measurements,Measurement errors,Electromagnetic diffraction
更新于2025-09-09 09:28:46