Aiming at the problem of singularity and mutation points after wavelet denoising with improved layered threshold when denoising the downlink signal received in the downhole in rotary steering drilling, a bilayer filtering denoising method based on singular value decomposition is proposed. This method combines wavelet denoising and singular value decomposition denoising, and adopts the WT-SVD bilayer filtering denoising method to construct a matrix of the wavelet improved layered threshold denoising signal, and then performs singular value decomposition and recovery on the matrix signal. The number of selected singular values and the structure of the reconstruction matrix were determined through experiments, and the signal waveforms, signal-to-noise ratio, root mean square error and correlation coefficients of three different denoising methods including singular value decomposition, wavelet improved layered threshold and WT-SVD bilayer filtering are compared and studied. The final experimental results show that the WT-SVD bilayer filtering denoising method is effective.
The funct i on of the servo p latform i s to control the borehole's deviat i on and or i entation by us i ng an automatic control method to dr i ve the platform sus p end i ng at a special angle. However, i t i s not an easy job to control th i s cylindr i cal and rotat i ng platform at a part i cular angle under the complex downhole env i ronment. The key to solve th i s p roblem is to establish a su i table nonl i near model. Based on the structure analysis of the p latform, a general law of dynam i cs equation is obtained by analyzing friction, dr i ll i ng fluid shock, eccentric action, etc. A hydraulic driving torque test has been done, wh i ch i nd i cates that the dynam i cs analys i s i s reasonable. The model l i es the foundat i on for the research of p latform's control method and the improvement of mechan i cal des i gn.
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