Angle Transducer Based on Matteucci Effect

Amorphous wires are a category of materials that exhibit features that make them suitable to be employed in sensors construction. In iron-rich magnetostrictive amorphous wires (MAW), several interesting effects occur, among which Villary, Wiedeman and Matteucci effects are most important. In particular, Matteucci effect consists in generation of sharp pulses between the ends of a straight MAW when it is concomitantly subject to an axial alternative magnetic field and to a torsion strain. The pulses amplitude is dependent on the intensity of the magnetic field and on the torsional degree, that is on the angle. In the paper, the construction, operation and features of a sensor devoted to measure rotational movements are presented, along with a method of signal conditioning designed to converting the peak amplitude of the sensor output pulses into frequency information. The experimental tests revealed good performances of the transducer, despite its low cost. An analysis of several external influence factors upon the transducer operation and characteristics is also performed.