Toward the Use of Permanent Magnets Consisting of Several Cylindrical Segments in Magnetostrictive Transducers of Displacements on Ultrasonic Torsion Waves

The article is devoted to issue of possible replacement ring permanent magnets in magnetostrictive transducers linear or angular displacements, used also in robotics, by construction from non-magnetic material of same shape and parameters, containing several permanent magnets of cylindrical shape. The elements of basic design acoustic path magnetostrictive transducer linear displacements and known mathematical models of processes excitation, translation and reading of analog output signal are analyzed. The forms of permanent magnets used in magnetostrictive displacement transducers and mathematical models used for modeling and calculations magnetic fields formed by permanent magnets are considered in detail. Investigations of magnetic fields formed by several cylindrical shaped segments are performed. Computational experiments to investigate dependence of projection total magnetic field strength created by segments on 0Z axis on z coordinate, as well as computational experiments to investigate strength in center of structure made of non-magnetic material allowed us to draw conclusions about possibility of replacing the ring permanent magnet with structure including several permanent magnets of cylindrical shape. Also, results of computational experiments have shown necessity of taking into account the distance between segments, increase of which contributes to sharp decrease in the amplitude total value of magnetic field strength. It is noted that possible replacement of ring permanent magnets by several segments of cylindrical shape allows not only to obtain required for excitation of ultrasonic wave of total value magnetic field strength, but also in general to reduce the cost of magnetostrictive transducers of linear displacements, used including in robotics.