Self-starting Characteristics of Magnetic Controlled Spiral Capsule Robots

The low power consumption and operability of magnetic controlled spiral capsule robots (MCSCRs) are important indexes that influence the interventional diagnosis and treatment of digestive tract.However, existing studies lack of analysis on the self-starting characteristics of MCSCRs.For simple and effective swimming of a MCSCR in a liquid environment, a self-starting characteristic model of MCSCR was proposed.A new portable electromagnetic propulsion device with dynamic rotating magnetic field and a MCSCR were also developed.A spatial magnetic field distribution model of a permanent magnet was constructed in accordance with the Biot-Savart law.This model was employed to determine the coupling characteristic relation between master and slave permanent magnets.A self-starting model of robots in a pipe filled with liquid was deduced, and the interaction laws of self-starting rotating speed, fluid viscosity, and axial thrust were determined.Results demonstrate that the self-starting rotating speed of robots increases with the increase in fluid viscosity, and the axial thrust is enhanced gradually as rotating speed increases.When the fluid viscosity is 0.1 Pa•s, the self-starting rotating speed reaches the minimum value (85 r/min).Self-starting control of robots with a low torque and a strong axial thrust can be realized by adjusting the self-starting distance and rotating speed between the master permanent magnet and robot.When the master permanent magnet is 29 mm away from the robot, the maximum coupling magnetic moment is the lowest (0.1 Pa•s).This study can provide theoretical supports to low-power rapid medical examination based on in vivo capsule robot.