Movement of a Cableless In-Piping Magnetic Actuator With a New Propulsion Module

It is important to inspect pipes used in nuclear power plants and reactors. A number of studies have investigated various locomotion mechanisms of robots controlled by electric cables in pipes. A cableless actuator capable of movement in narrow pipes of less than 15 mm has not yet been developed. The present paper proposes a novel cableless magnetic actuator with a propulsion module that exhibits a high thrusting force. The effect of the magnetic forces generated by two different propulsion modules on the movement of the cableless actuator was investigated theoretically and experimentally. The proposed actuator includes an electrical inverter that directly transforms DC from button batteries into AC. Experimental results indicate that the proposed actuator can move vertically at a speed of 225 mm/s, using the power provided by 10 button batteries when pulling no load mass. This cableless magnetic actuator has several possible applications, including inspection of small pipes.