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The integration of high-precision robotics and magnetic resonance imaging (MRI) exhibits the potential to enhance the accuracy and safety of MRI image-guided surgery. However, the potential hazards associated with conventional electromagnetic servomotors in strong magnetic fields have hindered the development of MRI-compatible robotics. To address this issue, this article proposes and implements a novel magnetic-free wireless drive system that creatively integrates capacitive power transfer with ultrasonic motors to realize the truly wireless self-direct drive without strong magnetic field interference. The proposed system overcomes the drawbacks of existing wireless motors requiring microcontrollers, power switches and communication modules at the motor side, facilitating high-degree integration and maintenance-free operation. In addition, a dual-mode wireless drive control scheme is proposed to achieve the full-speed range wireless direct drive. Promisingly, the proposed system is unaffected by coupling mechanism misalignment and load variation, ensuring precise manipulation with high robustness. Both theoretical analysis and experimental results are conducted to verify the effectiveness of the proposed wireless motor system.

This article proposes a dynamic wireless charging scheme for electric vehicles (EVs) using autonomous frequency control. The key is to make the receiver circuit of an EV always operate in the splitting region by adopting proper transmitter coils and displacement between adjacent transmitter coils. Then, by sensing the primary current, the autonomous frequency control can achieve constant charging power in the splitting region even the EV is moving. The operating frequency of the system is monitored online. When the operating frequency indicates that the EV is leaving the current transmitter coil and approaching the next transmitter coil, the current transmitter circuit stops working and the next transmitter circuit starts to work, thus achieving continuous charging on the road. Both theoretical calculations and experimental results are given to validate the feasibility of the proposed scheme.