Patent ID: 7512468
Filing Date: 2009-03-31
Classification: B62D

Abstract:
1. An electric power steering apparatus comprising: a motor which generates a steering assist force; a steering angle determining part which determines measurement based steering angles based on concurrently measured values; a straight travel judging part which judges whether or not a vehicle is in a state of straight forward motion; a mean reference angle determining part which determines a mean reference steering angle by dividing total of said measurement based steering angles, which are determined when the vehicle is judged to be in a state of straight forward motion, by a number m of judgments that the vehicle is in a state of straight forward motion which is a number of said measurement based steering angles which are totaled; a corrected steering angle determining part which determines a corrected steering angle by subtracting a steering angle midpoint from a presently determined measurement based steering angle wherein said mean reference steering angle is used as said steering angle midpoint; a steering angle based correction part which corrects an output of said motor in accordance with a steering angle output correction value determined on a basis of the corrected steering angle; and a gain application part applying said steering angle output correction value to correct the output of said motor wherein an absolute amount of said steering angle output correction value applied for a given corrected steering angle is increased as the number m of said measurement based steering angles which are totaled to determine said mean reference steering angle increase.