Influence of External Conductive Objects on the Performance of an Ironless Inductive Position Sensor

The ironless inductive position sensor (I2PS) is a novel device that measures high-precision linear position without being affected by radiation and external magnetic fields. Built on the basis of the linear variable differential transformer, the I2PS senses the variation of flux linkage between the supply and sense coils which is related to the linear position of the moving coil. This paper characterizes the magnetic performance of the I2PS through a detailed analysis of the impact of axisymmetrical external conductive objects on the sensor. This characterization is performed through a set of finite element simulations and through dedicated experiments. Axisymmetrical conductive objects result in offset voltages, but the differential measurement techniques combined with high-resolution calibration curves mitigate this effect.