A new variable reluctance-Hall Effect based angle sensor

A simple but efficient angle sensor designed and developed by combining variable reluctance technique and Hall-Effect sensing principle is presented in this paper. This new sensor possesses the best features of both the schemes and overcomes the demerits of reluctance type sensors. It proposes the use of a spiral shaped element which rotates in unison with the target whose angular position is to be sensed. The rotating spiral varies the reluctance in the flux path of a Hall Effect sensor as sensing angle changes. The resulting variation in the Hall sensor output is shown to be linear using finite element analysis. The scheme does not require any complex signal conditioning circuitry. A simple electronic scheme for calibrating the proposed sensor output against changes in various electrical, magnetic and mechanical parameters is also presented. A prototype angle sensor assembly based on the proposed principle has been built and tested. The output obtained from the sensor was found to be linear, as expected, across a wide range with a worst-case error less than 1%. The new sensor will be useful for various scientific and industrial angle sensing applications.