In-piping actuator capable of free movement in a thin complex pipe

This paper proposes a magnetic actuator of a new type that exhibits a very high thrusting force and is capable of a reversible motion in a complex pipe. The magnetic actuator of the reversible type due to opening and closing of a compound material by using elongation and contraction of four shape-memory-alloy (SMA) coils was fabricated. The magnetic actuator moves by difference in frictional force between forward and backward supporting force of the compound material. Experimental result shows that the prototype actuator was able to climb at 38.7 mm/s in the straight pipe when pulling the load mass of 50 g. In addition, the measurement of an average speed carried out for two patterns of movement in a complex pipe with many curved parts and step parts. The prototype actuator was able to move in the complex pipe over the average speed of 35 mm/s. This actuator has many possible applications, including small pipe inspection.