A Coupling Mechanism With Multidegree Freedom for Bidirectional Multistage WPT System

For the application of wireless power transfer (WPT) technology in robot arm, it is necessary to provide flexible power supply for each arm device across multiple arm joints. However, rotation of the joints and the variation of the loads will lead to the fluctuation of the output voltage at each stage. To guarantee stable output voltage, a bidirectional multistage WPT (BM-WPT) method is proposed to provide energy for multiple loads. A bowl-coupling structure and three-dimensional orthogonal ring coil arrangement are proposed to reduce coupling variation against joint rotation. With a special resonant topology design for each stage, energy can be injected or output freely on each stage regardless of energy transfer direction. This topology can also reduce the sensitivity of the output voltages with the variation of the loads. The simulation and experimental results have verified the effectiveness of the proposed method and the coupling mechanism.

Automated summary

A bidirectional multistage wireless power transfer (BM-WPT) method is proposed to provide flexible power supply for multiple arm devices, featuring a bowl-coupling structure and three-dimensional orthogonal ring coil arrangement to reduce coupling variation against joint rotation. Special resonant topology design for each stage allows energy to be injected or output freely regardless of energy transfer direction, ultimately reducing sensitivity of output voltages with load variation. Simulation and experimental results confirm the effectiveness of the proposed method.