Operational numerical simulation of a four-spiral in-pipe robot

Abstract

Based on an in-pipe robot with four spiral bodies in its tail, the dynamics equations of the fluid in the pipe are established when the robot runs. By using the computational fluid dynamics (CFD) method, the robot’s force, circumferential torque and pressure on the pipe are numerically analyzed when the spiral directions of four spiral bodies are alternately left-handed and right-handed or are all left-handed, and different spiral directions correspond to different rotational directions. When the robot is needed to change direction, the rotational directional combinations of the four spiral bodies are calculated and designed. The results show that when the spiral directions of four spiral bodies alternate and the rotational directions of spiral bodies with different spiral directions are different, the formed axial thrust forces are the same, and the formed radial forces are counterbalanced, so that the robot moves axially in a balanced state. When the spiral and rotational directions of four spiral bodies are the same, the uniform axial thrust forces and a certain circumferential torque are formed, so that the robot moves axially in a rotating state. Under the two conditions, the robots can achieve turning arbitrarily. The turning directions of the four-spiral robots only relate to the rotational directions of the robotic spiral bodies. By contrasting the numerical values and the experimental values of the thrust forces between the cylinder and the spiral ribbed plate in the reference, the correctness of the numerical calculation method used in this paper is verified. The above research shows that such multi-spiral in-pipe robots are suitable to achieve inspection, dredging and other functions.