Propulsion and Control of Microrobot Using a Multi-Selective Wireless Power Transfer Coil

Microrobots have been actively studied in recent years due to their mobility and usability. It is important to receive electrical energy from outside through wireless power transfer (WPT) system because active circuits, such as sensors and microrod controller unit, should be included and operating time should be sufficient to increase the usability of microrobot. In this research, we propose a multi-selective WPT coil and structure to maximize the usability of the microrobot that can receive electrical energy with wireless power transmission systems and can be propelled and rotated at the same time. The proposed multi-selective WPT coil system architecture is described with a theoretical explanation of the magnetic force acting on the microrobot. To verify the proposed model, it has been verified through simulation and experimental verification that the time-varying magnetic field generated from four transmitting coils is suitable for the propulsion, generating torque, and power transmission of microrobot. To validate the proposed system, a 3 mm-sized microrobot is used for experimentation. The experimental results show that the microrobot is able to freely move and rotated as intended by controlling the external incident magnetic field.