Design and comparative analysis of self-propelling drill bit applied to deep-sea stratum drilling robot

Abstract

目的 海底地层钻探机器人作为一种新型的海底地层地质调查手段具有广阔的应用前景。本文旨在分析并设计一种新型的自推进式螺旋钻头,以减小机器人在地层中运动时的前端阻力。 创新点 1. 通过理论建模分析,推导出新型自推进螺旋钻头的螺旋升角与土壤钻屑排出运动的关系;2. 建立仿真模型,成功模拟钻头在海底土壤中的钻进过程,并通过其贯入力和扭矩分析其自推进效果;3. 设计试验装置,成功模拟钻头在土壤中的钻进过程,并通过其贯入力和扭矩进一步验证其自推进效果。 方法 1. 通过理论推导,构建螺旋叶片升角与土壤钻屑排出运动之间的关系,得到具有设计优势的新型自推进钻头。2. 通过Abaqus有限元仿真软件,采用耦合欧拉-拉格朗日方法进行钻头钻进过程的仿真分析,可视化观察钻头钻进过程对周围土壤的扰动范围(图9);对比自推进钻头与传统锥形钻头在相同转速下轴向贯入力上的差别,确定其自推进效果的优势(图10)。3. 通过试验,进一步验证所设计的自推进钻头在配制的模拟海底土壤中的减阻钻进效果(图14)。 结论 1. 自推进钻头钻进过程对周围土壤的影响范围小于传统锥形钻头;2. 自推进钻头能够靠排出土屑提供推进力,因而有着更小的钻进阻力;3. 自推进钻头的轴向推进力随着转速的增加而不断增大,所以较高转速有着更好的钻进减阻优势;4. 自推进钻头的扭矩高于传统锥形钻头。 Robotic subsea stratum drilling robot is a method for new subsea stratigraphic geological investigation and resource exploration. Resistance at the front end is the main source of resistance to the robot’s motion in the strata. Since there is no continuous and strong downward drilling force as in conventional drilling rigs, robot movement relies heavily on the drill bit to reduce the drilling resistance. In this study we propose a self-propelling drill bit that can discharge soil debris to provide propulsive force and reduce the resistance. The key parameter of the drill bit design, the spiral blade lead angle, was determined by theoretical analysis of the drill bit’s soil discharging effect. To verify the structural advantages of the self-propelling drill bit in reducing resistance, a comparative analysis with a conventional conical drill bit was conducted. The drilling process of both bits was simulated using finite element simulation at various rotation speeds, the penetration force and torque data of both drill bits were obtained, and tests prepared accordingly in subsea soil were conducted. The simulations and tests verified that the penetration force of the self-propelling drill bit was lower than that of the conventional conical drill bit. The self-propelling drill bit can reduce the resistance effectively, and may play an important role in the stratum movement of drilling robots.