A robot fish encapsulated by an electromagnetic wave-transmitting plastic film

This manuscript describes a robot fish, the surface of which is composed of a flexible thin plastic film. Its internal mechanism, including an actuator (e.g. a servomotor), is encapsulated in the plastic film by a vacuum packaging machine. This plastic film has electromagnetic wave-transmitting properties, allowing sensors, wireless charging modules, and communication devices to be arranged within the device. To simplify the waterproofing and pressure resistance properties of the robot, the inner portion of the robot fish is filled with insulating fluid, such as industrial oil. The transmission performances of these devices, which utilize electromagnetic waves, may worsen due to the tendency of water or insulating fluids to attenuate the electromagnetic waves. This study therefore experimentally investigated the transmission performance of these devices, while taking into account the effects of water or insulating fluid. These devices were subsequently applied to our fish robot; enabling us to verify its performance by using infrared sensors to assess its autonomous locomotion.