Dynamic Modeling and Analysis of the Drill Stem in the Lunar Soil Drilling Sampler

Mechanics researches related to the drill stem of the lunar soil drilling sampler mainly focus on the interaction characteristics between the drill stem and the soil at present, while the mechanical analysis of the drill stem itself is relatively less and can't reflect the actual working process. Aimed at this problem, it is presented in this paper that the flexible multibody dynamic model of the drill stem in the initial stage of drilling on lunar surface and the analysis results obtained by using the variable-length beam-shaft element. It turned out that to improve the drilling precision of the sampler, it is necessary to set up a special amplitude limiting mechanism between the rotating drive mechanism and the fixed support and lower the amplitude limiting mechanism in a suitable position to constitute an approximate clamped constraint with the fixed support to the drill stem. Works in this paper could provide theoretical basis for the design of amplitude limiting mechanism and raise the reliability of the lunar soil drilling sampler accordingly.