Improving the Accuracy of Magnetostrictive Linear Position Sensors

Magnetostrictive (MS) sensors are based on the transmission of ultrasonic signals in a waveguide and constitute an interesting alternative to optical encoders for long-range absolute high-precision measurement of linear position. Despite their inherent conceptual simplicity, many aspects of the sensor design must be considered to achieve an accuracy in the 10-mum range. This paper describes research in a new kind of MS linear position sensor, focusing on the enhancement of the processes of generation, transmission, and reception of the ultrasonic waves, with the aim of obtaining high measurement accuracy. Empirical results obtained with a sensor prototype indicate an improvement of six times over the precision of standard MS sensors.