Patent ID: 6738725
Filing Date: 2004-05-18
Classification: B62D,G01D,Y10T

Abstract:
A rotation angle detector comprising:a rotating member rotating in conjunction with a body of rotation to be measured, an angle sensor disposed in the vicinity of said rotating member to detect a periodical angle position thereof, a non-volatile data memory for storing the standard position of said angle sensor, an operation/control means that the performs operation/processing of the standard position and the detection data from the angle sensors to determine the periodicity of said rotating members, calculates an absolute rotation angle of said body of rotation to be measured to provide a detection output, and when a stop signal is received from outside, changes from a normal operation mode of continuously reading detection data from said angle sensors and performing the operation/processing thereof to stop mode of suspending said operation/processing, and a rotation detection means to detect that said rotating members have rotated to a prescribed angle position during said stop mode; wherein said operation/control means causes to store the values of angle position and periodicity of said rotating member at the time point when the stop mode is switched to, temporarily releases said stop mode by an output signal received from said rotation detection means, determines a value to correct the periodicity of said rotating member based on the change of angle position of said rotating member taking place during a period from the start of said stop mode to its release and uses this value for correction, and wherein during the normal operation mode the ignition switch is on and during the stop mode the ignition switch is off.