Research On In-situ Detection Technology Of Deep Sea Cobalt-rich Crust

The deep-sea cobalt-rich crust is an important mineral resource in the ocean,which is rich in rare metal elements and is of great significance for the detection of cobalt-rich crusts.At present,the detection of cobalt-rich crusts mainly uses acoustic detection methods.However,limited by ocean exploration technology,the study of cobalt-rich crusts mainly focuses on detecting the growth distribution of cobalt-rich crusts,and there are few studies on the thickness and mineral amount of cobalt-rich crusts in the primary environment.Manned submersibles provide a technical support platform for in situ detection of cobalt-rich crusts,providing a new direction for their research.The research topic of this paper comes from the national key research and development plan of the National Deep Sea Base Management Center,“Deep Sea Key Technologies and Equipment”.This paper will rely on the “Dragon” manned submersibles of the National Deep Sea Base Management Center for research,aiming to realize the thickness detection and mineral estimation of cobalt-rich crusts by ultrasonic waves through the “Dragon” manned submersible platform.Experimental study on acoustic characteristics of cobalt-rich crusts and wave noise reduction studies on ultrasonic waves.The specific research mainly includes:(1)Analyze the research progress of cobalt-rich crust detection technology at home and abroad,clarify the research using acoustic detection technology,and formulate the research road map.The cobalt-rich crust was tested experimentally for the unknown problem of the acoustic properties of cobalt-rich crusts.The test system was designed and built,including signal excitation system and signal receiving system.The underwater ultrasonic transducer was used to support the virtual instrument signal acquisition equipment.The LabVIEW host computer acquisition software was designed and the acoustic characteristics of the cobalt-rich crust were tested.(2)The ultrasonic echo denoising algorithm was studied for the problem of severe noise interference in the ultrasonic echo signals of cobalt-rich crusts.The common signal denoising algorithm was studied and analyzed,and the wavelet threshold denoising algorithm was used to denoise the echo signal.The MATLAB algorithm was used to process the collected echo signals,and the signal-to-noise ratio of the noise-reducing signals of different parameters was studied to determine the optimal noise-reduction parameters.Software implementation of each core module of the noise reduction algorithm was performed using the C++ language.(3)For the calculation of the thickness of cobalt-rich crust,the echo signal detection algorithm of cobalt-rich crust was studied in the case that the two echo signals cannot be accurately located at the corresponding time.The algorithm of signal envelope extraction was studied,and the method of Hilbert transform was used to extract the signal envelope.The ultrasonic echo time detection algorithm was designed based on Hilbert transform,and the thickness was measured by this algorithm.The cobalt-rich crust thickness calculation software was designed.In order to make the software have a better interactive experience,the main interface and logic flow of the software were realized by C# language.At the same time,in order to improve the operating efficiency of the software,the C++ language were used to implement software for noise reduction,envelope extraction,echo peak recognition and other functions,and a dll module was generated for reference by C#,and the overall function of the thickness measurement software was realized.The data obtained by thickness measurement was accurate and effective.(4)In order to solve the problem of cobalt-rich crust minerals,the method of using the thickness value information to realize the cobalt-rich crust minerals was studied.Firstly,the thickness value information was combined with the position information in the manned submersible navigation and positioning system to realize the three-dimensional processing of the thickness value information,and the discrete value cloud data of the thickness value was generated.The algorithm of discrete point surface fitting was studied.The differential improved algorithm was used to improve the B-spline surface fitting,and the algorithm was verified by simulation.Finally,the method of estimating the cobalt-rich crusts was verified by experiments.The experimental results show that the ore estimation can be realized.