| The deep sea contains abundant mineral resources,which are important resource guarantees for the future development of human society.In recent years,countries around the world have conducted extensive explorations around the mining of deep-sea polymetallic nodules.This article combines the demand for precise assessment of deep-sea polymetallic nodule resources and summarizes and analyzes the current research progress in the field of polymetallic nodule sampling,deep-sea bottoming operation robots,polymetallic nodule hydraulic sampling technology,and deep-sea thin and soft substrate walking theory both domestically and internationally.A continuous sampling technology scheme for polymetallic nodules with a stable seabed operation platform is proposed.The following aspects of research work are mainly carried out for this technical solution.1.Key mechanical analysis.Based on related research results,a hydraulic sampling process mechanical model established in a discrete manner was elaborated,providing a reference for subsequent numerical analysis research.The key mechanical characteristics involved in the deepsea thin and soft bottom tracked walking mechanism,such as pressure settlement relationship,shear displacement relationship,and adhesion characteristics,have been sorted and analyzed,providing a basis for subsequent design.2.Research on the overall scheme,system design,and integration of a continuous sampling robot for polymetallic nodules.Based on the characteristics of the existing substrate environment and the distribution of polymetallic nodules,the overall scheme design is completed through functional requirement analysis method.The key components of the continuous sampling robot,including the walking mechanism,sampling mechanism,hydraulic system,and power transmission and distribution system,have been designed.And based on the designed individual components,the overall layout and integration of the entire machine were completed.The deep-sea polymetallic nodule continuous sampling robot is composed of a walking mechanism,sampling mechanism,motor pump group,valve group,oil tank,landing balance propeller,electronic compartment,buoyancy material,high-definition camera,pan head,etc.3.Key performance analysis of a continuous sampling robot for polymetallic nodules.Based on the technical parameters of the deep-sea polymetallic nodule continuous sampling robot,a three-dimensional model of the hydraulic sampling mechanism,walking mechanism,and robot machine was constructed.By constructing the internal flow field of a hydraulic sampling mechanism and virtual ore based on mining area abundance data,sampling and conveying flow field analysis were carried out with nozzles of different sizes and pump pressures.After analysis,it was found that the sampling performance was good under the conditions of pump water pressure of 90 k Pa,sampling nozzle diameters of 9mm(front)and 7mm(rear),and conveying gap of 3.5mm.A simulation analysis was conducted on the walking characteristics of the robot under sparse soft substrate and its stability under complex terrain using 3D multi body dynamics software.The maximum climbing angle of the robot was obtained to be 13 °.The trajectory correction of complex terrain was achieved by adjusting the track parameters,providing a reference for offshore operation control.Through analysis and research,it has been shown that continuous sampling robots can complete various tasks through speed control in terrains of 10 ° and below.4.Laboratory experiments and sea trials.Based on the requirements of offshore applications,laboratory tests were conducted on the sampling performance of continuous sampling operation robots and the overall sampling walking performance,verifying the sampling,walking and other functions and performance of continuous sampling robots,providing a foundation for subsequent offshore experimental applications.The continuous sampling robot is equipped with exploration voyages for polymetallic nodule mining areas in China,and has completed offshore verification tests in the eastern Pacific Ocean.In the sea trial,the water depth was 5246 m,and a total of 6 hours and 38 minutes of underwater operation were conducted.Functional and performance tests such as seabed sampling and stable seabed walking were completed,and 18.9kg of nodule samples were obtained.The settlement depth,lifting angle,and walking data of its track meet the design requirements.The feasibility of the overall technical scheme of the continuous sampling robot for polymetallic nodules has been verified through sea trials. |
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