Patent ID: 6768956
Filing Date: 2004-07-27
Classification: G01D

Abstract:
A position detecting apparatus for converting an output signal from a position sensor which outputs two signals which periodically vary in correspondence with measured displacement and which differ 90Â° in phase, into position information, comprising:an offset memory, an offset remover for removing an offset value stored by the offset memory from two output values of the position sensor, respectively, and an interpolation calculator for converting two output values of the offset remover into a position signal, a signal memory for storing the two output values of the position sensor, a distance calculator for calculating a square of a difference of the stored value of the signal memory with respect to each of the two output values, and for calculating a square root of a value derived by adding the two values after the squaring calculations, and a distance integrator for integrating the output value of the distance calculator; a signal multiplier for multiplying the two output values of the position sensor by the output value of the distance calculator, and a signal integrator for integrating the two output values of the signal multiplier; an instructor for issuing a storage instruction and an integration instruction to the signal memory and the signal integrator, respectively, when the output value of the distance calculator exceeds a fixed value; a divider for dividing two output values of the signal integrator with the output value of the distance integrator, and an offset value setting device for setting the two output values of the divider in the offset memory, after each period change of the position sensor output signal.