Displacement sensors using longitudinal and torsional elastic waves in magnetostrictive wires are con tactless, absolute sensors that calculate displacement from the delay time of the waves. A sensor using torsional elastic waves has not yet been developed for displacements longer than 5 [m], because of elastic wave attenuation. Therefore, we performed an experiment on elastic wave propagation in two magnetostrictive wires to find a wire capable of carrying high-amplitude elastic waves. As a result, we found that Ni-span-C is very practical, and that a sensor with Ni-span-C can be used for displacement up to 15 [m]. A displacement sensor using magnetostrictive wire is suitable for use in the carrier system of a linear motor. But the gap between the mover and magnetostrictive wire fluctuates when the sensor is shaken. Therefore, we measured the variation in the output voltage of gap fluctuation and found that, even if the gap fluctuates up to 15 [mm], elastic waves can be detected.
