A practical implementation of wireless power transfer systems for socially interactive robots

Socially Interactive Robots (SIR) have many applications in rehabilitation, including psychological development of children with autism, children with complex neuro-developmental motor impairments, adults with dementia, etc. The animal-shaped or toy-shaped SIR should help engaging such individuals in physical and communication interaction, while any human presence during such sessions is typically counterproductive. A particularly critical moment is recharging or replacing of robot batteries, since that is typically done by adults, but also because it includes removing the animal-like cover and revealing the real nature of the object. Thus, there is a strong need for a total autonomy of SIRs, and it is wireless power transfer (WPT) that can make charging of such robots autonomous without human intervention. In this research, a complete WPT charging system is designed for recharging of an m3Pi robot, which includes primary power conversion units; transmitter and receiver compensation circuits, coils and magnetic couplers; as well as a regulated charging converter at the robot side. The best engineering practice is employed to design this WPT as a fully controlled and autonomous wireless recharging system for robots. It includes: optimized couplers and resonant circuits to provide maximum efficiency and satisfy safety standards while transferring a specified amount of power; a four-loop regulated system capable of controlling the primary dc voltage and coil current, as well as implementing regulated constant-current constant voltage (CCCV) battery charging algorithm; wireless communication modules for synchronization and coordination of the primary and secondary converters. In this paper, the most important analytical, simulation and experimental results are presented.