High-performance actuators and advanced control technologies are increasingly needed in the field of medical, welfare, housework and entertainment robot. Especially, the next generation humanoid robots are expected to exceed human physical exercise． And various kinds of actuators which have suitable performance and size for their body parts will be needed. In this paper, we notice that Connected electro-circuit simulation with electromagnetic analysis will support the robot actuator development in the future. And also we clarify that the analysis by common motor model is useful for design tools.