Mechanism analysis and structural design of a spiral drilling robot in loose media

ObjectiveAiming at the lack of research on drilling robots in loose media and insufficient analysis of soil-spiral drilling mechanisms, a new type of spiral drilling robot was designed to meet the practical needs of efficient drilling and flexible obstacle avoidance.MethodsFirstly, kinematics and dynamic models were established through the analysis of soil-spiral interaction to reveal the core mechanism of single spiral drilling deflection. Secondly, a left-right-left combined propulsion mechanism was designed to offset deflection, and a 3R1T hybrid mechanism was matched to realize spatial 3D steering. Thirdly, Matlab software was used to analyze the workspace of the hybrid mechanism to verify steering flexibility. Finally, a discrete element and multibody dynamics (DEM-MBD) coupled simulation model was established to comprehensively verify the mechanism performance.ResultsThe simulation results indicate that the multi-spiral combination controls the deflection error of a single spiral within 3%, and the hybrid mechanism has 3R1T degrees of freedom and sufficient workspace. The robot drills 150 mm axially within 9 s, with the vertical displacement controlled within 35 mm, which effectively solves the problem of single spiral deflection and realizes efficient drilling and flexible steering in loose media, providing a reference for the design of similar robots.