Abstract: A dime-size inchworm-like robot, which adopts wireless power transmission for power supply, has a great potential for a minimally invasive intestinal exploration. The powering coil onboard the robot is usually composed of a ring-shaped ferrite core and a ring-shaped winding. This paper presents a fast design method for power coil. Firstly, the integrated environment model of the powering coil is established by modeling the geometry of the ring-shaped winding, measuring the permeability distribution of the ferrite core, and analyzing the influence of eddy-current effect of the metal parts on the powering coil. Then, by referring to electromagnetic theory, the equivalent series resistance and mutual inductance of the powering coil are calculated. Finally, axial location, number of layers, number of turns, and wire diameter of the winding are optimized, with an aim of maximizing the output power of the powering coil and with a consideration of temperature rise safety and limited space. And some guiding rules for selecting the design parameters are obtained. The optimized winding, having a compact size of (12.0—12.4)mm×9.9mm, can output an electric power of 1478.3mW.

Key words: wireless power transmission, inchworm-like robot, onboard powering coil, integration environment, rapid design and optimization