| The 21st century is an era of ocean development,seabed exploration and energy development from shallow sea to deep sea,more and more ocean projects have been completed and put into use.The seabed surface is the important boundary of ocean exploration and the foundation of ocean engineering construction.Therefore,accurate acquisition of mechanical properties and environmental parameters of seabed sediments is of great significance to the development of Marine resources and the construction of Marine engineering.In this paper,by studying the new seabed cone penetration testing and sampling system,the multi-parameter insitu testing and low-disturbance sampling of 3000m deep-sea seabed sediments are realized,which accurately and efficiently reflect the property characteristics of seafloor sediments in the in-situ environment,and can be widely used in Marine engineering geological investigation.The main research contents are as follows:First of all,by analyzing the requirements of detecting the engineering properties of seabed sediments,the overall scheme of seabed cone penetration testing and sampling system is designed.The system mainly consists of three parts:seabed penetration platform,static probe rod and sampling tube,which correspond to the underwater carrier function,static probe parameter in-situ measurement function and sediment sampling function of the system respectively.The seabed penetrating platform is the underwater carrier and working base of the whole system.Therefore,centering on its main functional characteristics and from the aspects of structural form and driving mode,the research on multi-functional and highly integrated penetration platform is carried out to realize the efficient and stable operation of the whole system in the complex Marine environment.Secondly,the hydraulic system of seabed penetration platform is studied,which mainly includes clamping hydraulic circuit and penetration hydraulic circuit.The precise control of the position of the hydraulic cylinder is realized by adopting electro-hydraulic proportional position control in the penetration hydraulic circuit,which further ensures the uniform and stable penetration speed.Stable penetration velocity can improve the accuracy of static contact detection data and reduce the disturbance of sampling tube to undisturbed sediment during sampling.Then,considering the complexity of the deep-sea in-situ test environment,the control strategy of the hydraulic system is studied.By establishing the fuzzy PID control method,the on-line self-tuning of the control parameters is realized,thus effectively reducing the influence of variable load on the penetration velocity and improving the control accuracy of the hydraulic system.Meanwhile,the electro-hydraulic co-simulation of the hydraulic control system is carried out based on AMESim and Simulink software.The results show that compared with traditional PID controller,fuzzy PID controller has better dynamic performance,higher control precision and stronger robustness.Finally,the assembly,land test and offshore test of the whole system were completed,and further sea application test was carried out.In the Shenhu area of the South China Sea,an insitu test was carried out on board the research ship "Marine Geology No.9".Successfully obtained Nine in-situ parameters,including mechanical and chemical parameters,for sediments within a depth range of 2.66m on the seabed surface at a depth of 1820m.The experimental results show that the hydraulic penetration system has high speed control precision and good anti-jamming ability.It has been verified by sea test that this seabed cone penetration testing and sampling system can meet the requirements of in-situ detection of deep-sea sediments,and can be widely used in offshore engineering reconnaissance.The research content and results of this paper have an important guiding role and application value for the development of Marine static sounding technology in China. |
