The approach to calibrate the coefficient of total harmonic distortion of power quality analyzers using reference standard non-harmonic waveform signals, instead of the traditionally used set of harmonic signals is co...
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ISBN:
(纸本)9781665445375
The approach to calibrate the coefficient of total harmonic distortion of power quality analyzers using reference standard non-harmonic waveform signals, instead of the traditionally used set of harmonic signals is considered in [1]. Using a reference calibrator, square, triangular, saw-shaped signals and a truncated sine wave signal are generated in series, which provide setting of appropriate reference values of the total harmonic distortions for which the analyzer is calibrated. In the present work, a computer-based automation system and algorithm for calibration of Power Quality Analyzer are proposed by THD. The algorithm performs the sequence of operations for control of the reference calibrator and the calibrated analyzer, setting reference values of THD of the voltage/current from the calibrator, performing multiple measurements at the calibration point, measured results are extracted from the analyzer and their processing and an estimate of the actual value of the measured THD values and an estimate of the extended uncertainty is obtained at the analyzer calibration point.
In projector-based applications, if the laser spot of a laser pointer can be quickly and accurately tracked, the laser pointer can act as an alternative to a computer mouse, and thus a user can more conveniently inter...
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In projector-based applications, if the laser spot of a laser pointer can be quickly and accurately tracked, the laser pointer can act as an alternative to a computer mouse, and thus a user can more conveniently interact with the computer from a distance. Presented is an efficient calibration algorithm, which is immune to both the geometry of projection surfaces and the distortion of optical lens, for laser pointer tracking. Experiments verify the effectiveness of the proposed algorithm.
This paper reports the development and experimental evaluation of an in-situ calibration algorithm of the misalignment mounting angle matrix between the Strapdown inertial navigation system (SINS) and Doppler sensor w...
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This paper reports the development and experimental evaluation of an in-situ calibration algorithm of the misalignment mounting angle matrix between the Strapdown inertial navigation system (SINS) and Doppler sensor which are practically used for accurate underwater navigation. Most previously reported methods required the SINS to be aligned first to output accurate attitude before the calibration. By separately treating the body frame and the navigation frame attitude update, the algorithm in this paper could be simultaneously carried out during the SINS attitude alignment stage. Simulation and experiment results show that the calibration could be done in 300 s and the position error during the navigation is less than 0.8% of the voyage distance.
An approach for calibrating of the AC voltage of True RMS voltmeters is proposed, using reference square waveform signals instead of the traditionally used harmonic (sinusoidal) signal. A computer-based automation sys...
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ISBN:
(纸本)9781665445375
An approach for calibrating of the AC voltage of True RMS voltmeters is proposed, using reference square waveform signals instead of the traditionally used harmonic (sinusoidal) signal. A computer-based automation system and an algorithm for calibration of True RMS voltmeters have been implemented. The algorithm performs the sequence of operations for control of the reference calibrator Metrix CX1651 and the calibrated True RMS voltmeter PICOTEST M3500A, setting reference voltage values from the calibrator, performing multiple measurements at the calibration point, extracting measured results and extracting the measured results to obtain an estimate of the actual value of the measured voltage values and an estimate of the extended uncertainty at the calibration point. Based on the results of calibrations, the two approaches were analyzed and compared, which proved their equivalence.
Air pollution poses a significant threat to human health, yet traditional monitoring platforms and reference-grade instruments are costly and offer limited spatial coverage. This study developed a custom-designed sens...
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Air pollution poses a significant threat to human health, yet traditional monitoring platforms and reference-grade instruments are costly and offer limited spatial coverage. This study developed a custom-designed sensor system that integrates electrochemical sensors with a microcontroller for data collection and processing. Various algorithms were tested for sensor data calibration, with the random forest algorithm delivering the highest accuracy and lowest error. Further analysis emphasized the importance of temperature and relative humidity in improving the predictive accuracy of the models, particularly for the calibration of CO and Ox sensors. Model performance was significantly enhanced by using larger training datasets, requiring 28 days of data for optimal calibration of CO and NO sensors. In contrast, the NO2 and Ox sensors performed well with smaller datasets (7 days or more). The sensor system was further employed to monitor variations in particulate matter concentrations and examine the relationships among different pollutants. Results show that reducing NOx and O3 concentrations to 50% of their original levels led to a 25% and 5% decrease in PM, respectively, but their simultaneous reduction resulted in only a 15% decrease, suggesting a nonlinear interaction between these pollutants and PM. The system was also used to monitor air quality inside and outside subway stations, providing real-world validation of the performance of the sensor system and demonstrating its versatility. Overall, this study demonstrates the feasibility and effectiveness of the custom-designed sensor system for air quality monitoring, emphasizing its potential for high-resolution sensor network deployment and its capability to generate valuable data to inform urban air quality policy decisions.
In this paper, the spectral characteristics, performance of spaceborne radiation source, in orbit infrared radiometric calibration method and radiance data generation process of the Medium Resolution Spectral Imager (...
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In order to improve the low output accuracy caused by the elastic deformations of the branch chains,a finite element-based dynamic accuracy analysis method for parallel mechanisms is proposed in this ***,taking a 5-pr...
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In order to improve the low output accuracy caused by the elastic deformations of the branch chains,a finite element-based dynamic accuracy analysis method for parallel mechanisms is proposed in this ***,taking a 5-prismatic-spherical-spherical(PSS)/universal-prismatic-universal(UPU)parallel mechanism as an example,the error model is established by a closed vector chain method,while its influence on the dynamic accuracy of the parallel mechanism is analyzed through numerical *** to the structural and error characteristics of the parallel mechanism,a vector calibration algorithm is proposed to reduce the position and pose errors along the whole motion ***,considering the elastic deformation of the rod,the rigid-flexible coupling dynamic equations of each component are established by combining the finite element method with the Lagrange *** elastodynamic model of the whole machine is obtained based on the constraint condition of each moving part,and the correctness of the model is verified by ***,the effect of component flexibility on the dimensionless root mean square error of the displacement,velocity and acceleration of the moving platform is investigated by using a Newmark method,and the mapping relationship of these dimensionless root mean square errors to dynamic accuracy is further *** research work provides a theoretical basis for the design of the parameter size of the prototype.
Aiming at the problem of large irregular workpiece positioning difficulty and large error, a new workpiece positioning method is presented. The research object of this paper is a large porous irregular workpiece with ...
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Aiming at the problem of large irregular workpiece positioning difficulty and large error, a new workpiece positioning method is presented. The research object of this paper is a large porous irregular workpiece with holes as the processing location of the workpiece. For this porous workpiece, a special calibration tool is designed and an appropriate calibration algorithm is selected to complete the calibration of the tool. And a relative calibration method is designed. This method uses a small number of holes on the workpiece as the calibration point, and combines the data of the 3D model of the workpiece to calculate the poses of all the holes of the workpiece. Using the robot teaching method, take the pose data of part of the hole on the workpiece, and calculate the calibration error by combining the hole pose obtained above. The experimental results show that the deviation meets the calibration requirements.
The presence of sensor array errors due to mutual coupling and channel mismatch among array sensors severely degrades the performance of direction-of-arrival (DOA) estimation algorithms. This paper proposes a novel se...
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ISBN:
(纸本)9781479958368
The presence of sensor array errors due to mutual coupling and channel mismatch among array sensors severely degrades the performance of direction-of-arrival (DOA) estimation algorithms. This paper proposes a novel sensor array errors calibration algorithm based on iterative least squares with projection (ILSP) algorithm, which suits for arbitrary array and only needs one auxiliary signal source. This algorithm firstly estimates the true steering vector by using ILSP, then estimates the sensor array errors by solving the equation between the nominal steering vector and the true steering vector. Comparative computer simulation results are presented to illustrate that the proposed algorithm still has lower computational complexity and higher calibration accuracy on the condition of less snapshots and minor DOA intervals of different sampling time.
The inevitable capacitor mismatch due to the process variation is one of the major bottlenecks in high-resolution ADC (Analogue to Digital Converter) design. In this work we propose a new compensation strategy which a...
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ISBN:
(纸本)9781665484855
The inevitable capacitor mismatch due to the process variation is one of the major bottlenecks in high-resolution ADC (Analogue to Digital Converter) design. In this work we propose a new compensation strategy which adopts the DEM (Dynamic Element Matching) technique to conventional cyclic ADCs with minimum hardware cost. Theoretical analysis has been done first, and to the best of authors' knowledge, it is the first time that the relation of the capacitor mismatch, output deviation and THD (Total Harmonic Distortion) has been mathematically established. Consequently, the statistical distribution of expected THD under certain mismatch can be derived. Based on that we further analyse the effect of DEM in frequency domain, which effectively performs a harmonic shaping function to the original output spectrum. Simulation results show that the DEM compensation strategy can effectively boost the worst SINAD (Signal to Noise and Distortion Ratio) figure from 68.8 dB to 89.5 dB (99.7% yield) under 0.1% capacitor mismatch and 32x oversampling ratio scenario.
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