Design And Analysis Of Drilling Guiding Mechanism For Drilling-sampling Soil

One of the main targets of China’s Phase Ⅲ Lunar Exploration Project is to acquire lunar soil sample more than two meters deep under lunar surface and bring it back to the earth. As an important part of drilling sampling device, design of drilling guiding mechanism is a key to ensure successful sampling. However, how to design a better performance guiding mechanism is still an unsolved problem. For high sampling reliability, it will be a promotion if a guiding mechanism is researched.After functional requirements and technical specifications are analyzed, design elements of the drilling guiding mechanism are extracted to design reasonable configuration.Multi-scheme guideways are proposed according to style of friction and contact. For the purpose of comprehensively evaluating the advantages and disadvantages of each scheme, analytic hierarchy process is used to establish an evaluation model. Qualitative and quantitative analytical methods are used to calculate weight for each scheme,thus providing a basis for the multi-scheme optimation of guide mechanism programs.For optimized configuration of guiding mechanism, key structural parameters are extracted. Mechanical boundary conditions and external load equivalents are analyzed to establish guiding precision, drill deflection and Hertz contact stress mathematical models. Relationship between performance indexes and structure parameters is obtained to determine the range of structural parameters. Theoretical basis for the structural design of drilling guiding mechanism is provided.Function of each component and mechanical environment in the drilling samling task are acquired. Structural design of key components is completed and the corresponding static analysis and environmental adaptability are analyzed. Finite element analysis is used to simulate drilling and sampling limit conditions to analyze stiffness and strength of guiding mechanism.Parameter settings for simulation are introduced, virtual 3D guiding mechanism is built in ADAMS to simulate lunar surface limit conditions. Disturbing force is applied to the tool in different directions, contact force at each support and displacement of the rig mass center are analyzed to verify the correctness of hydrostatic model and analyze anti-bias load capacity of each plane. Guiding precision is computed to evaluate performance-oriented and provide a theoretical reference for the design and analysis of drill core institutions and limiting structure.