| Drilling strategy is a key to accomplish the automated drilling and coringmission in lunar exploration. Based on the current drilling and coring mission inlunar exploration of China, this paper aims at the construction of drilling strategyfor the drilling and coring device through the online drillability of lunar regolithrecognition.Fristly, the interaction between lunar regolith and drilling tool is analyzedbased on passive earth pressure theory. By using the principle of least energyconsumption and the related constraints, the drilling parameters of granular regolithcan be established. The drilling parameters of massive lunar rocks can also beobtained by analyzing the interaction between lunar rocks and drilling tool.Secondly, the pattern recognition methods are adopted to identify thecharacteristics of drilling parameters. Identification model is constructed to identifythe drilling characteristics of the typical specimen. Experiments are conducted toanalyze the influence of drilling parameters and identification model parameters onrecognition results, which can be used to optimize the identification model.Referring to the drillability classification method of rock in geology on theearth, the concept of drillability of lunar regolith is proposed to classify the drillingcharacteristics on the moon. Typical specimens of lunar regolith are made to coverthe possible drilling characteristics of lunar regolith including loose lunar Regolithand hard lunar rock. Several typical lunar specimens are permutated randomly toestablish the lunar regolith simulant. The online monitoring signals are sampled toextract the drilling features and identify the drillability level at the current position.The optimal drilling strategy for typical lunar specimens and the identifieddrillability levels are correlated to adjust the current drilling strategy in the drillingprocess. Experiments are carried out to confirm the drilling strategy that can meetthe requirements in lunar exploration. |
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