High-frequency and High-powered Electromagnetic Actuation System Utilizing Two-stage Resonant Effects

This article presents a novel design and a control methodology for an electromagnetic actuation (EMA) system that can generate a high-frequency and high-powered electromagnetic field for enhanced electromagnetic torque and force. The proposed system consists of a two-stage resonance effect control circuit utilizing resonant effects and an automatic capacitance switching method matching the desired frequency. The first resonant effect control stage, which is called the series resonance, is comprised of various capacitors connected with the EMA system and is designed to compensate for rapid impedance change and phase delay. The second resonant effect control stage, which is called the current-amplified resonant circuit, is integrated to amplify coil currents for a high-frequency operation. In addition, the automatically controllable continuous capacitance switching method is proposed to enhance the magnetic field with respect to the desired operating frequency in a wide range. Finally, the resonance control system is applied to the conventional EMA system. In-vitro experiments were conducted on three-dimensional locomotion and a drilling motion control for a helical-shaped microrobot. Both simulation and experimental results showed a significant improvement in the microrobot locomotion ability, speed (235%), and driving force (900%) with respect to the conventional design. The developed EMA control circuit and algorithm can magnify the input current nearly twice the conventional EMA system and extend the operating frequency to a maximum of 370 Hz.