Wireless Power Transfer-Based Microrobot with Magnetic Force Propulsion Considering Power Transfer Efficiency

Abstract

A microrobot that could continuously receive both electrical energy and propulsion force from a wireless power transfer system would offer tremendous benefits. However, wireless powering systems produce a time-varying magnetic field that can be harmful if the generated magnetic field needed for microrobot movement is large. To limit exposure, power transfer efficiency must be enhanced. This paper derived and analyzed the magnetic force applied to a microrobot from a wireless power transfer system. Unlike previously introduced Lorentz force-based microrobot propulsion, the proposed method is independent of a wireless power transfer system's frequency. Therefore, this frequency can be determined considering maximum power transfer efficiency. The theoretical analysis and simulation by numerical analysis were compared, and results were verified though actual fabrication and measurement. Analyses of the transmitting and receiving coils were conducted. The optimum force, with less than 9% discrepancy, was determined while achieving a 3.6% improvement in power transfer efficiency.