A Novel Cableless Magnetic Actuator Capable of Movement in a Pipe

This paper proposes a novel cableless magnetic actuator that exhibits a very high thrusting force and is capable of being adapted to propel a robot within a pipe. This actuator contains a mechanical inverter that directly transforms DC from button batteries into AC. The mechanical DC–AC inverter incorporates a one-degree-of-freedom-mass-spring system and a curved beam with a concentrated copper mass that switches under an electromagnetic force. The actuator is moved by the difference in frictional force between forward and backward supporting force of flexible materials like a rubber. It is able to move through a pipe of 8 mm inner diameter. Experimental results show that the actuator can move upwards at a speed of 35.3 mm/s without a load mass. Further, the results suggest possibility of reversible motion of the cableless magnetic actuator. This cableless magnetic actuator has many possible applications, including inspection and maintenance of the pipes.