DISPLACEMENT SENSOR AND COMPENSATION OF MEASUREMENT ERRORS THEREOF

摘要

PURPOSE: A displacement sensor and a method for compensating measurement errors of the displacement sensor are provided to compensate the measurement errors on a real time basis, thereby obtaining an accurate measurement value in respect to the detection position of the displacement sensor. CONSTITUTION: A displacement sensor (S) includes a transceiving unit (10), a magnetostrictive ray unit (20), a position variable magnet unit (30), and a position-fixed magnet unit (40). The transceiving unit transmits current pulses and receives ultrasonic waves generated by the current pulses at the same time. A magnetic field is formed on the magnetostrictive ray unit in the circumferential direction by the current pulses, and an axial magnetic field is formed on the magnetostrictive ray unit by a permanent magnet so that the magnetostrictive ray unit induces a combined magnetic field. The combined magnetic field is transmitted via the ultrasonic waves. The position variable magnet unit varies the position according to the magnetostrictive ray unit and measures the distance to the transceiving unit by transmitting reflective waves in respect to the ultrasonic waves to the transceiving unit.