scholarly journals A Phase Difference Measurement Method Based on the Extended Kalman Filter for Coriolis Mass Flowmeters

2019 ◽  
Vol 19 (2) ◽  
pp. 48-52
Author(s):  
Nan Chen ◽  
Shangchun Fan ◽  
Dezhi Zheng
Keyword(s):  
Kalman Filter ◽  
Extended Kalman Filter ◽  
Phase Difference ◽  
Measurement Method ◽  
Measurement Accuracy ◽  
Single Phase ◽  
Signal Frequency ◽  
Difference Measurement ◽  
Mallat Algorithm ◽  
Interference Signals

Abstract According to the characteristics of stable single-phase flow, a phase difference measurement method based on the extended Kalman filter is proposed in this paper for use with Coriolis mass flowmeters. Firstly, the Mallat algorithm is applied to filter out interference signals. Then, the frequency and phase difference of the two reconstructed signals are detected through the extended Kalman filter. Compared with the sliding Goertzel algorithm or discrete time Fourier transform, the proposed method does not need to predict the signal frequency and avoids quadratic error. Simulations and experiments show that the proposed method has stronger anti-interference, higher measurement accuracy and lower relative error than the existing method based on the Hilbert transformation.

scholarly journals Vibration Error Correction for the FOGs-Based Measurement in a Drilling System Using an Extended Kalman Filter

2021 ◽  
Vol 11 (14) ◽  
pp. 6514
Author(s):  
Lu Wang ◽  
Yuanbiao Hu ◽  
Tao Wang ◽  
Baolin Liu
Keyword(s):  
Kalman Filter ◽  
Extended Kalman Filter ◽  
Measurement Accuracy ◽  
Original Data ◽  
Calibration Method ◽  
Error Model ◽  
Nonlinear Error ◽  
Measurement While Drilling ◽  
Drilling System ◽  
Vibration Error

Fiber-optic gyroscopes (FOGs)-based Measurement While Drilling system (MWD) is a newly developed instrument to survey the borehole trajectory continuously and in real time. However, because of the strong vibration while drilling, the measurement accuracy of FOG-based MWD deteriorates. It is urgent to improve the measurement accuracy while drilling. Therefore, this paper proposes an innovative scheme for the vibration error of the FOG-based MWD. Firstly, the nonlinear error models for the FOGs and ACCs are established. Secondly, a 36-order Extended Kalman Filter (EKF) combined with a calibration method based on 24-position is designed to identify the coefficients in the error model. Moreover, in order to obtain a higher accurate error model, an iterative calibration method has been suggested to suppress calibration residuals. Finally, vibration experiments simulating the drilling vibration in the laboratory is implemented. Compared to the original data, compensated the linear error items, the error of 3D borehole trajectory can only be reduced by a ratio from 10% to 34%. While compensating for the nonlinear error items of the FOG-based MWD, the error of 3D borehole trajectory can be reduced by a ratio from 44.13% to 97.22%. In conclusion, compensation of the nonlinear error of FOG-based MWD could improve the trajectory survey accuracy under vibration.

Research on Algorithm of Phase Difference Analysis Based on an Improved Windowed FFT

2013 ◽  
Vol 765-767 ◽  
pp. 2399-2402
Author(s):  
Bu Xin You ◽  
He Zhi Liu ◽  
Peng Tian ◽  
Jia Xu ◽  
Jing Bu
Keyword(s):  
Phase Difference ◽  
Phase Measurement ◽  
Measurement Theory ◽  
Simple Algorithm ◽  
Correction Method ◽  
Signal Frequency ◽  
Small Scale ◽  
Difference Measurement ◽  
Frequency Independent ◽  
System Frequency

Based on the small scale power system frequency fluctuation frequency leakage problems due to the FFT phase measurement error problem, this paper presents a high accuracy algorithm for phase difference measurement based on windowed discrete Fourier transform, the signal truncated using 4 order Blackman-Harris window, and corrects the phase correction method for discrete spectrum thus to calculate the phase difference. The algorithm for phase difference measurement theory and signal frequency independent, so there is no need to sample the signals of the whole cycle. A simple algorithm, less calculation, high precision, has strong inhibition on the harmonic and noise, simulation results verify the feasibility and effectiveness of the algorithm.

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